JP2000080599A - Bulk paper manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing bulky paper having a large thickness, high absorption, excellent softness, and moderate toughness. SOLUTION: This method for producing bulky paper 3 having a pattern formed thereon comprises transporting a fiber sheet 2 with a prescribed moisture content to a pattern-imparting step installed before a drying step and having a sucking part and a prescribed open hole pattern net 31 surrounding the sucking part, sucking the fiber sheet in a state put on the open hole pattern net to impart a pattern corresponding to the pattern of the open hole pattern net 31 to the sucked fiber sheet, and drying the pattern-imparted fiber sheet in a drying process to provide the objective bulky sheet having the pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing bulky paper used for absorbent papers such as cooking papers, paper towels, tissues, cleaning paper products and sanitary materials.

[0002]

2. Description of the Related Art Conventionally, attempts have been made to produce bulky paper having improved thickness, water absorption capacity and softness in view of the production process. For example, in a method for producing bulky paper, a wet fiber sheet before drying is subjected to patterning by suction, then passed through hot air without being compressed, intermediately dried, and finally dried by a Yankee dryer. Hole area is 0.007
A method using an aperture pattern conveying belt having a diameter of ² mm ^{2 to} 2.1 mm ² and having 100 to 3600 apertures per 6.45 cm ² (Japanese Patent Laid-Open No. 52-21405).
Or a method using an aperture pattern transport belt in which an aperture pattern resin having a predetermined aperture shape portion using a photosensitive resin and a paper transport belt conventionally used as reinforcement are combined. JP-A-5-506277 and JP-A-5-506893) are known.

However, the method described in Japanese Patent Application Laid-Open No. 52-21405 cannot deflect a softwood pulp composed of relatively long fibers into an opening to form a low-density projection.

[0004] In the methods described in JP-A-5-506277 and JP-A-5-506893, if the area of the opening is smaller than 3 mm ² , the volume of the low-density projection formed by suction is reduced. Because of its small size, it cannot exhibit sufficient thickness, water absorption capacity, and softness. Also, because the resin part of the hole pattern conveyor belt rubs against the surface of many reversing rolls and Yankee dryers under strong pressure,
There is a problem with the life of the belt. Also, it takes a lot of time to remove or replace the paper, and it has been impossible to alternately produce normal paper and bulky paper, or simply change the pattern shape of the bulky paper.

[0005] Accordingly, an object of the present invention is to increase the thickness,
An object of the present invention is to provide a method for producing bulky paper having high absorbency, excellent softness, and moderate strength. It is another object of the present invention to provide a method for producing bulky paper which can cope with long-term continuous operation and which can easily be switched to normal papermaking and the pattern shape can be easily changed.

[0006]

Means for Solving the Problems The present inventors have achieved the above object by performing patterning by a patterning step having a specific opening pattern net at a specific stage in a bulky paper manufacturing process. I knew that I could get it.

According to the present invention, a water content of 50 to 99 is applied to a pattern applying step which is provided before a drying step and includes a suction portion and an opening pattern net which circulates along the suction portion.
% Of the fiber sheet is transferred, and the fiber sheet is sucked while being held on the opening pattern net, and the fiber sheet is patterned corresponding to the opening pattern net. A method for producing a bulky paper obtained by drying to obtain a patterned bulky paper, wherein the opening pattern net has one opening area of 3 to 8 mm ² and an opening area ratio of 15 to 65%. The minimum width of the component forming the pattern in the planar direction is 0.2 to 5 m.
m, the thickness is 0.5 to 3.0 mm, and the tensile strength in the longitudinal direction is 20 kg / cm or more.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the method for producing bulky paper of the present invention will be described below in detail with reference to the drawings.
The apparatus (papermaking machine) 1 shown in FIG. 1 includes a pattern forming step including a suction drum 34 and an opening pattern net 31 circulating along a part of the peripheral surface of the suction drum 34, a paper layer forming step and a drying This is a bulky paper manufacturing apparatus installed between the steps, and the apparatus 1 includes a raw material supply unit 10, a paper layer forming unit 20, a pattern applying unit 30, a drying unit 40, and a winding unit 50.

The raw material supply section 10 includes a papermaking raw material supply head 11, and a fiber suspension adjusted to a predetermined concentration is supplied from the papermaking raw material supply head 11 to the paper layer forming section 20. The paper layer forming unit 20 includes the paper layer forming belt 2.
1 and a suction box 22 for dehydration provided adjacent to the paper layer forming belt 21. The paper layer forming belt 21 is composed of a wire mesh belt used in a normal paper machine. On the other hand, the suction box 22
Is a fiber sheet 2 formed on the paper layer forming belt 21.
And the moisture content of the fiber sheet 2 conveyed to the pattern applying section 30 in the downstream process is adjusted. In addition, the transport pickup belt 23 runs from the paper layer forming section 20 to the pattern applying section 30 and the drying section 40 described below, thereby enabling stable transport of the fiber sheet 2. The suction box 24 is provided with the paper layer forming belt 2.
1 transfers the fiber sheet 2 to the transport pickup belt 23. The pattern providing unit 30
Is provided with a suction drum 34 and an aperture pattern net 31 that circulates along a part of the peripheral surface thereof. As shown in FIGS. 2A and 2B, the opening pattern net 31
It is composed of a wire mesh belt. As shown in FIG. 1, the suction box 37 is disposed inside a portion where the opening pattern net 31 runs along the peripheral surface of the suction drum 34, whereby the suction box 37 is disposed through the opening pattern net 31. Air is sucked from the outside toward the inside. The pattern imparting section 30 is provided with an air nozzle 38 and a weak suction box 39, by which the fiber sheet 2 stuck to the aperture pattern net 31 is re-transferred to the transport pickup belt 23. It is easy to do. The drying unit 40 includes a drum-shaped through-air dryer (hereinafter, referred to as a drum-shaped through-air dryer)
(Referred to as a dryer) 41 so that hot air passes from the outside to the inside of the peripheral surface of the drum. A mesh net 42 is provided on the peripheral surface of the dryer 41. As the net 42, a net having an opening that does not hinder the passage of hot air is used. Further, a suction box 43 is provided near the lower end inside the dryer 41 to facilitate the transfer of the fiber sheet 2 transferred from the pattern applying section 30 onto the mesh net 42. . The winding unit 50 includes a winder 51 for winding the bulky paper 3 thus manufactured.

The apparatus 1 will be described in more detail. In the pattern applying section 30, the opening pattern net 31 circulating along a part of the peripheral surface of the suction drum 34 is described.
As shown in FIGS. 2A and 2B, is a net formed by weaving a resin linear body (in the present embodiment, a plain woven net), and has a square opening over the entire surface. Part 3
5 are formed to form a mesh-like pattern.

In order to pattern the wet fibrous sheet 2 by suction, the above-described apertured pattern net 3 is used.
It is important to use a patterning process with a 1 and a suction box 34. The pattern applying step may be installed at any position between the paper layer forming step and the drying step in the apparatus 1.

The opening 35 of the opening pattern net 31 shown in FIGS. 2A and 2B has an area of 3 to 8 m.
m ² , preferably 4 to 7 mm ² . If the area is less than 3 mm ² , the fibers are not sufficiently deflected into the apertures 35, and good low-density projections (corresponding to a low-fiber density region described later) are formed in the obtained bulky paper. Does not reach. Also, if it exceeds 8 mm ² , the fibers will fall off due to suction, and holes will easily be formed in the obtained bulky paper,
Further, the area of a mesh-like high-density region (corresponding to a high-fiber-density region described later) formed in the bulky paper becomes small, and a bulky paper having sufficient strength cannot be obtained.

The area of the opening 35 is related to the area ratio of the opening in the opening pattern net 31. In the present invention, each area of the opening 35 is in the above-mentioned range. In addition, the opening area ratio is set to 15 to 65%. If the opening area ratio is less than 15%, the area of the entire region in which the low-density projections are formed becomes small, so that it is not possible to obtain a bulky paper having a high absorption capacity and excellent texture. If the opening area ratio exceeds 65%, the area of the entire area forming the high-density area becomes small, and bulky paper having sufficient strength cannot be obtained. The opening area ratio is preferably 35 to 60%. In this specification, the area ratio of the opening is defined as the opening pattern net 31 described above.
Means the value measured for the area where the opening 35 is formed, for example, the left and right sides of the opening pattern net 31 where the opening 35 is not formed are excluded from the measurement target area. You.

The area of the opening 35 is also related to the width of a net component 36 (see FIGS. 2A and 2B) forming (surrounding) the opening 35 in the opening pattern net 31. are doing. In the present invention, the individual area of the opening 35 is set in the above-mentioned range, and the minimum width of the component 36 in the plane direction (that is, when the opening pattern net 31 is viewed in plan) is set to 0. It is 2 to 5 mm. If the width is less than 0.2 mm, the line width of the mesh-like high-density region formed in the obtained bulky paper becomes too thin, and a bulky paper having sufficient strength cannot be obtained. 5
If it exceeds mm, the line width of the mesh-like high-density region formed in the obtained bulky paper becomes too large, resulting in a paper having a hard texture. The minimum width of the component 36 in the planar direction is:
0.4 to 3 mm, preferably 0.5 to 2 mm
Is more preferable. In addition, the minimum width of the constituent material referred to in the present specification refers to the width of the narrowest part when the constituent material is viewed in a plan view when the width of the constituent material is not constant. When the width of the component is constant, it refers to the width.

The thickness T of the opening pattern net 31 (see FIG. 2B), in other words, the depth of the opening 35 is 0.5 to 3.0 mm, and 0.7 to 2 mm. .5mm,
In particular, it is preferably 1.0 to 2.0 mm. If the thickness T is less than 0.5 mm, the fibers are not sufficiently deflected into the apertures 35, so that good low-density projections cannot be formed in the obtained bulky paper. If it exceeds 3.0 mm, the state of deflection of the fibers into the apertures 35 will be constant, and holes will easily be formed in the bulky paper obtained during high suction.

The aperture pattern net 31 is preferably water-repellent from the viewpoint of papermaking stability (easiness of peeling of the fiber sheet 2 adhered to the aperture pattern net 31). More preferably, the opening pattern net 31 is used.
Preferably has a water repellency having a contact angle with water of 60 ° or more, particularly 75 ° or more. By using such an apertured pattern net, the releasability from the apertured pattern net can be further improved when the fiber sheet adhered to the apertured pattern net by the patterning by suction is transferred to another conveyor belt. It becomes more suitable for high speed papermaking. In order to express the above water repellency,
When the material of the aperture pattern structure 32 is hydrophilic, it is preferable to perform a water-repellent coating treatment, specifically, a surface treatment with a Teflon resin or a urethane resin. The release properties can also be improved by spray-adding a release agent such as a polyolefin-based release agent, a higher fatty acid-based release agent, or a mineral oil-based release agent to the hole pattern structure. The contact angle was measured using a CONTACT ANGLEMETER CA-D manufactured by Kyowa Interface Science Co., Ltd. at a temperature of 25 ° C., by dropping 10 microliters of water onto a small sample plate (76 mm × 26 mm) of the aperture pattern structure with a syringe. Later, it is measured quickly.

Since the opening pattern net 31 is basically used so as to go around independently, it is necessary that the opening pattern net 31 has sufficient strength to withstand the turning. For this purpose, the tensile strength of the opening pattern net 31 in the longitudinal direction (circumferential direction) is set to 20 kg / cm or more, preferably 40 kg / cm or more, and more preferably 6 kg / cm or more.
0 kg / cm or more. The tensile strength is 20kg
If it is less than / cm, stable running of the hole pattern net in a paper machine or a processing machine becomes impossible. The tensile strength is determined by measuring the breaking strength using a tensile strength tester, and the conditions are as follows: the width of the specimen is 10 mm, and the distance between the chucks is 100 m.
m, the tensile speed is 60 mm / min.

The opening pattern net 31 has the opening area, the opening area ratio, the thickness and the tensile strength in the above ranges, and the minimum width of the component in the planar direction is in the above range. As long as it is used, the same plastic net made of a linear woven fabric used as a usual conveyor belt for papermaking and processing can be used. Further, a net made of glass fiber, Kevlar fiber, metal thread, or the like can be used.

The method for producing bulky paper using the apparatus 1 shown in FIG. 1 will be further described. First, a fiber suspension is supplied from the papermaking raw material supply head 11 onto the paper layer forming belt 21, By depositing the fibers on the forming belt 21,
A fiber sheet (paper layer) 2 in a wet state is formed. still,
The concentration of the fiber suspension is not particularly limited and can be appropriately selected from a range in which the paper layer forming step can be stably performed.

Next, the moisture in the fiber sheet 2 is dehydrated in the suction box 22, and the moisture content of the fiber sheet 2 before patterning is set to a predetermined value. The moisture content is to allow the fiber sheet 2 to be sufficiently patterned.
50 of the weight of the fiber sheet 2 (that is, the weight in a wet state)
To 99% by weight, preferably 65 to 90% by weight, more preferably 70 to 85% by weight. If the water content is less than 50% by weight, the degree of freedom of each fiber in the wet fiber sheet 2 is low, so that it is difficult to reconstruct the fiber structure by suction. The structure of the sheet 2 cannot be maintained, and it becomes difficult to convey the sheet 2.

The fiber sheet 2 adjusted to a predetermined moisture content is separated from the paper layer forming belt 21 and transferred onto the opening pattern net 31. In the suction drum 34 installed on the inner circumference of the orbiting pattern net 31, air is sucked from the outside to the inside by the suction box 37 through the opening pattern net 31. Therefore, the fiber sheet 2
Of these, a region located on the hole 35 in the hole pattern net 31 (this region is referred to as “region A”)
Is drawn into the opening 35 by the suction and becomes a convex shape whose thickness increases toward the inside of the suction box 37. The area A is a low fiber density area in which the fiber density of the constituent fibers is lower than before the suction.

On the other hand, the portion of the fiber sheet 2 located on the component 36 of the apertured pattern net 31 and the vicinity thereof (this region is referred to as “region B”) Since it is pressed against 36 and compressed, its thickness becomes slightly smaller and its fiber density becomes slightly larger than before suction. That is, the area B is
It becomes a high fiber density area relatively to the area A. Such a high fiber density region has the effect of suppressing the tendency of the tensile strength of the resulting bulky paper to decrease due to the low fiber density region. In particular, as described above, since the aperture pattern net 31 is formed from a continuous mesh pattern, the high fiber density region also becomes a continuous mesh pattern, and the tensile strength of the obtained bulky paper is further improved.

As described above, while the opening pattern net 31 travels along a part of the peripheral surface of the suction drum 34, the mesh pattern of the opening pattern net 31 is applied to the fiber sheet 2. Is performed.

The suction force of the suction box 37 in the pattern applying step depends on the basis weight, the water content, and the like of the fiber sheet 2, but a general range is -10 to -1.
00 kPa, preferably -25 to -70 kP
a is more preferable.

The fiber sheet 2 on which a predetermined pattern is formed in the pattern applying step is then introduced into the dryer 41 as a drying step, and is dried by passing through hot air. At this time, a consolidation step generally performed in a normal papermaking process is not performed. The reason for this is to prevent the bulkiness of the resulting bulky paper from being impaired.

The fiber sheet is dried while the dryer 41 makes one full rotation to obtain a bulky paper 3 as a final product. The obtained bulky paper 3 is wound by the winder 51 in the winding section 50.

The bulky paper 3 is manufactured by the above-described steps. In the present invention, the pattern applying step including the suction drum 34 and the aperture pattern net 31 is provided before the drying step. There are the following advantages (1) to (5), which cannot be obtained by the method for producing bulky paper. (1) Since the fiber sheet can be patterned without guiding the opening pattern net 31 into the drying step,
An aperture pattern structure made of a non-heat-resistant material having a softening point of 250 ° C. or less can be used. (2) Since the opening pattern net 31 only circulates along a part of the peripheral surface of the suction drum 34, it is not necessary to manufacture a net that is so long. (3) The pattern shape applied to the fiber sheet 2 can be easily changed by a simple operation of merely replacing the opening pattern net 31. (4) Since the opening pattern net 31 is not guided into the drying step, it is hardly deteriorated even if it is used continuously for a long time, and its service life is extended. (5) By moving the entire pattern imparting section 30 downward to remove the aperture pattern net 31 from the travel path of the fiber sheet 2, normal papermaking can be easily produced,
Switching to normal papermaking is easy.

FIG. 3 schematically shows the structure of the cross section of the bulky paper thus obtained. As shown in FIG. 3, the bulky paper 3 obtained by the above-described method has a low fiber density region 4 and a high fiber density region 5. The low fiber density region 4 is
It is formed corresponding to the opening 35 in the opening pattern net 31 and has a relatively large thickness. On the other hand, the high fiber density region 5 is formed corresponding to the component material 36 surrounding the opening 35 in the opening pattern net 31, and has a relatively small thickness. As a result, the bulky paper 3 has an uneven structure, is extremely bulky, and has a large thickness. Therefore,
It has high absorbency and excellent softness. In addition, since the high fiber density region 5 having a high strength has a continuous mesh pattern, the bulky paper 3 has an appropriate strength.

As the fibers constituting the bulky paper 3, short fibers having a fiber length of 10 mm or less, particularly 0.5 to 5 mm are preferably used. Examples of such short fibers include wood pulp such as softwood or hardwood chemical pulp, semi-chemical pulp and mechanical pulp, mercerized pulp and crosslinked pulp obtained by chemically processing these wood pulp, non-wood fiber such as hemp and cotton, and rayon. Cellulose fibers such as regenerated fibers such as fibers; and synthetic fibers such as polyethylene fibers, polypropylene fibers, polyester fibers, and polyamide fibers. Among these fibers, cellulosic fibers such as wood pulp, non-wood pulp, and rayon fiber are preferable from the viewpoint of product cost, strength, suitability for papermaking, and the like. Above all,
From the viewpoint of product cost, wood pulp is more preferred. These staple fibers are preferably used in an amount of 50 to 100% by weight based on the entire fibers constituting the bulky paper 3.
More preferably, it is used in an amount of 0 to 100% by weight.

When the bulky paper 3 is used as a cleaning sheet that is impregnated with an absorbent substrate such as cooking paper, paper towel, tissue, etc., or a cleaning agent, the cellulosic fiber is used in an amount of 50 to 50% based on the entire fiber. It is preferable to contain 100% by weight. In addition to this,
It is also preferable to add a wet paper strength enhancer such as a polyamidoamine / epichlorohydrin resin in order to develop wet strength. Generally, it is preferable that the wet paper strength enhancer is added in an amount of 0.2 to 2.0% by weight based on the total amount of the bulky paper. It is also preferable to use a wet paper strength enhancer in which an appropriate amount of an anionic polymer such as carboxymethyl cellulose or an amphoteric polymer such as amphoteric polyacrylamide is mixed with the above-mentioned polyamidoamine / epichlorohydrin resin in order to develop higher wet strength.

FIG. 2 shows the opening pattern net.
In addition to those having the square openings shown in (a) and (b), those having openings having rectangular or other shapes, or any combination of these shapes can also be used. . Further, the aperture pattern net may be used in combination with another mesh belt or the like. Also,
In the apparatus shown in FIG. 1, the drying section 40 and the winding section 5
In addition to installing a Yankee dryer between 0 and 0, a creping doctor may be juxtaposed at the outlet of the Yankee dryer to further improve the texture of the resulting bulky paper. In this case, it is preferable to reduce the degree of drying of the fiber sheet in the dryer 41. Further, in the above-described embodiment, the case where patterning is performed on the wet fiber sheet formed in the line of the paper machine (in-line patterning) has been described as an example, but instead of this, normal papermaking is performed once. The paper obtained by the ordinary papermaking is rewet to form a fiber sheet having the above-mentioned moisture regain, and then, the fiber sheet is formed on the fiber sheet by using an apparatus in which the opening pattern net circulates along a suction portion. Patterning (offline patterning) may be performed. In addition, as for the point that the method for producing the bulky paper is not particularly described in detail, the description on the conventionally known paper making method is appropriately applied.

According to the present invention, the following is also provided. An apertured pattern net having a number of apertures for patterning the fiber sheet by suction while holding a fiber sheet having a moisture content of 50 to 99% by weight, wherein the apertured pattern net is Has a hole area of 3 to 8 mm ² and a hole area ratio of 15 to 65.
%, The minimum width in the plane direction of the component forming the pattern is 0.2 to 5 mm, the thickness is 0.5 to 3.0 mm, and the tensile strength in the longitudinal direction is 20 kg / cm or more. Hole pattern net. A bulky paper manufacturing apparatus that is provided before a drying step and includes a suction unit and a pattern applying unit including an opening pattern net that circulates along the suction unit, wherein the opening pattern net is one The opening area is 3 to 8 mm ² , the opening area ratio is 15 to 65%, and the minimum width in the plane direction of the component forming the pattern is 0.2 to 5
A bulky paper manufacturing apparatus characterized by having a thickness of 0.5 to 3.0 mm and a tensile strength in the longitudinal direction of 20 kg / cm or more.

[0033]

The following examples illustrate the effectiveness of the present invention. However, the scope of the present invention is not limited to such an embodiment.

Example 1 Softwood bleached kraft pulp (N
A mixed pulp raw material comprising 60% by weight of BKP, weight-average fiber length: 2.35 mm) and 40% by weight of bleached hardwood kraft pulp (LBKP, weight-average fiber length: 0.74 mm) was subjected to Canadian Standard Freeness (CSF) in a refiner. ) Beat to 640 ml. 0.6% by weight (based on pulp) of polyamideamine / epichlorohydrin resin WS-570 (manufactured by Nippon PMC) as a wet paper strength enhancer was added to a slurry obtained by dispersing the pulp raw material at 2% by weight. Carboxymethylcellulose (WS-A, Daiichi Kogyo Pharmaceutical Co., Ltd.) was added as an enhancer and a yield improver for the polyamidoamine / epichlorohydrin resin in an amount of 0.25% by weight (based on pulp) to obtain papermaking raw materials. Using the prepared papermaking raw materials, bulky paper was manufactured using the papermaking machine shown in FIG. The paper layer forming belt 21 in FIG. 1 is made of polyester 1,4 having a length of 90 mesh / inch × width of 85 mesh / inch.
-A satin woven belt was used.

Papermaking material supply head 1 of the papermaking machine shown in FIG.
1, the papermaking raw material was diluted to 0.1% by weight, supplied to a paper layer forming belt 21, and suction-dehydrated in a suction box 22 to form a fiber sheet 2 having a water content of 75% by weight. Next, the fiber sheet 2 is transferred to a perforated pattern net 31 that circulates along a part of the peripheral surface of the suction drum 34, and −33 kP is applied by a suction box 37 provided in the suction drum 34.
A predetermined pattern was given by suctioning with a. The aperture pattern net 31 has a square aperture shape as shown in FIGS. 2A and 2B and has one aperture area of 3.
7 mm ² , opening area ratio: 46.2%, width: 0.9 mm, thickness: 1.8 mm, tensile strength: 85 kg / cm in the longitudinal direction of the material forming the opening, and plain weave of polyester resin wire The obtained mesh belt was used.
The contact angle of the mesh belt with water is 77 °, so that the fiber sheet 2 can be easily separated from the mesh belt. The papermaking speed for producing bulky paper was 150 m / min.

The patterned fiber sheet 2 is transferred to the transport pickup belt 23 by the weak suction of the weak suction box 39 and introduced into the dryer 41. The fiber sheet 2 was dried by passing hot air at 250 ° C. in the dryer 41 to obtain bulky paper 3 having a basis weight of 22 g / m ² .

[Examples 2 and 3] Opening pattern net 3
A bulky paper having a basis weight of 22 g / m ² was produced in the same manner as in Example 1 except that the one shown in Table 1 was used as 1.

Comparative Example 1 A paper having a basis weight of 22 g / m ² was produced in the same manner as in Example 1, except that the suction box 37 was not used.

Comparative Example ² A paper having a basis weight of 22 g / m ² was produced in the same manner as in Example 1 except that the opening pattern net 31 shown in Table 1 was used.

Table 1 shows the production conditions of the above Examples and Comparative Examples.
Are shown together. Further, for the bulky paper of the above Examples and Comparative Examples, in order to examine the thickness, strength and absorbency,
Average dry thickness (under 3 g / cm ² load, under 23 g / cm ² load), average wet thickness (under 3 g / cm ² load, 23 g / cm ²
cm ² load), dry tensile strength (MD, CD), wet tensile strength (MD, CD), and saturated water absorption per unit area were measured by the following methods. Table 2 shows the results.

<Average Dry Thickness> Using a thickness gauge (R5-C) manufactured by Ozaki Seisakusho, 75 g of an acrylic plate having a bottom surface of 5 cm × 5 cm was placed on a piece of bulky paper and 3 g was placed.
The dry average thickness under a load of / cm ² was measured. In addition, put another 500g weight on the acrylic plate and 23g
The average dry thickness under a load of / cm ² was measured.

<Average wet thickness> 7 cm × 7 cm of bulky paper
After immersion in a large amount of water for 5 seconds, the water was drained for 10 seconds, and the average wet thickness was measured in the same manner as in the case of the average dry thickness.

<Dry Tensile Strength> After cutting bulky paper into strips having a width of 25 mm and a length of 100 mm, a tensile speed of 300 mm / mm was immediately measured using a universal compression tensile tester (RTM-25, manufactured by Orientic). The strength at break was measured under the conditions of a min. In Table 2, MD indicates the strength in the machine direction of the paper machine, and CD indicates the strength in the direction perpendicular thereto.

<Wet Tensile Strength> A bulky paper is cut into a strip having a width of 25 mm and a length of 100 mm, immersed in a large amount of water for 5 seconds, drained for 10 seconds, and then dried in the same manner as the dry tensile strength. The strength at break was measured.

<Saturated Water Absorption> The bulky paper is cut into 7 cm × 7 cm, immersed in a large amount of water for 20 seconds, drained for 30 seconds, and then weighed (g / 49 cm) of water absorbed by the bulky paper.
² ) was measured with a balance.

[0046]

[Table 1]

[0047]

[Table 2]

As is clear from the results shown in Tables 1 and 2, the bulky papers (Examples 1 to 3) obtained by the specific method using the specific opening pattern nets were different from the comparative examples. It can be seen that the thickness is large, the absorption is high, and the strength is moderate.

[0049]

As described in detail above, according to the method for producing a bulky paper of the present invention, a bulky paper having a large thickness, high absorbency, excellent softness, and appropriate strength can be obtained. Further, in the method for producing bulky paper of the present invention, since the fibrous sheet can be patterned without guiding the aperture pattern net into the drying step, an aperture pattern structure made of a non-heat-resistant material is used. it can. In addition, since the opening pattern net only circulates along the suction portion, it is not necessary to manufacture a net that is so long. Further, in the method for producing bulky paper according to the present invention, the pattern shape can be easily changed by a simple operation of simply replacing the above-mentioned perforated pattern net. In addition, the opening pattern net 3
Since No. 1 is not introduced into the drying process, it is hardly deteriorated even if it is used continuously for a long time, and its service life is extended. Furthermore, by simply moving the pattern applying step out of the running path of the fiber sheet, the production of ordinary paper can be facilitated, and switching to production of ordinary paper is easy.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an apparatus preferably used in the method for producing bulky paper of the present invention.

FIG. 2A is an enlarged plan view showing a main part of an aperture pattern net, and FIG. 2B is a plan view of FIG.
FIG. 2 is a sectional view taken along line II in FIG.

FIG. 3 is a schematic diagram showing a cross-sectional structure of a bulky paper obtained by the method for manufacturing a bulky paper of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 bulky paper manufacturing apparatus 2 fiber sheet 3 bulky paper 4 low fiber density area 5 high fiber density area 10 raw material supply section 20 paper layer forming section 30 pattern applying section 31 aperture pattern net 34 suction drum 35 aperture section 36 component 37 Suction box 40 Drying part 41 Drum-shaped through-air dryer 50 Winding part

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Toshiyuki Suga 2606 Kabane-cho, Akaga-cho, Haga-gun, Tochigi Prefecture In-house researcher (72) Inventor Hiroyuki Akai 2606 Kaiga-cho, Akabane-shi, Haga-gun, Tochigi Prefecture Kao Corporation Research Institute

Claims (4)

[Claims] 1. A fiber sheet having a water content of 50 to 99% by weight is transferred to a pattern applying step which is provided before a drying step and includes a suction part and an opening pattern net which circulates along the suction part. The fiber sheet is suctioned while being held on the aperture pattern net, and the fiber sheet is patterned by corresponding to the aperture pattern net, and then dried in the drying step to be patterned. A method for producing a bulky paper, wherein the opening pattern net has an area of one opening portion of 3 to 8;
mm ² , the opening area ratio is 15 to 65%, the minimum width in the plane direction of the component forming the pattern is 0.2 to 5 mm, the thickness is 0.5 to 3.0 mm, and the tensile strength in the longitudinal direction is 20kg
/ Cm or more. 2. The method according to claim 1, wherein the pattern applying step is provided between a paper layer forming step and a drying step of the paper machine.
A method for producing the bulky paper according to the above. 3. The method according to claim 1, wherein the patterned fiber sheet is
The method for producing bulky paper according to claim 1 or 2, wherein the paper is dried without passing through hot air to be consolidated. 4. The open pattern net has a water repellency having a contact angle with water of 60 ° or more.
3. The method for producing bulky paper according to any one of 3.