JP2000034690A - Production of bulky paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing fairly thick bulky paper with high absorbency, excellent softness and moderate robustness. SOLUTION: This patterned bulky paper is obtained according to the following process: a fibrous sheet 2 with a specified water content is transferred onto a patterning stage provided with a pattern net with open holes under revolution along a suction part, and sucked under the condition of being held on the net, and simultaneously with, or before or after the suction, provided with thermal energy at >=5 kcal/kg through a relevant device to effect patterning the fibrous sheet 2 correspondingly to the patterning net followed by drying the fibrous sheet 2 in a drying stage.

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 which is preferably used for absorbent papers such as cooking paper, paper towels, tissues, cleaning paper products and sanitary materials.

[0002]

2. Description of the Related Art In a conventional papermaking process, a flat paper layer forming belt or a conveyor belt having fine openings is used for forming a fiber sheet, and the fiber sheet is pressed uniformly. There is a method of performing dehydration processing, or a method of using a through-air drier for drying the fiber sheet by passing it through hot air without performing press dehydration processing. However, these methods have not yet reached the level of significantly increasing the thickness and water absorption capacity of paper.

JP-A-5-506277 and JP-A-5-506893 disclose an aperture pattern resin,
Using an open-hole pattern conveyor belt that combines the paper conveyor belt as a reinforcement, the wet fibrous sheet before drying is patterned by suction, and then passed through hot air without compression for intermediate drying. A method for producing bulky paper that is finally dried by a Yankee dryer is disclosed.

However, the technology described in the above publication is
Since the fiber sheet is transported to the drying process, the aperture pattern transport belt is also considerably long, requiring a great deal of labor and time for removal and replacement, and changing the pattern shape of bulky paper. Productivity was poor, for example, it was difficult.

[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. Another object of the present invention is to provide a method for producing bulky paper with high productivity.

[0006]

Means for Solving the Problems The present inventors perform patterning by a patterning step having an apertured pattern net by applying a specific amount of heat at a specific stage in a bulky paper manufacturing process. It has been found that the above object can be achieved.

According to the present invention, a water content of 5% is applied to a pattern providing step provided with an opening pattern net circling along a suction portion.
A fiber sheet of 0 to 85% by weight is transferred, and the fiber sheet is sucked while being held on the opening pattern net, and simultaneously with the suction or before and after the suction, the calorie application unit applies 5 kcal to the fiber sheet. / Kg or more by applying a heat amount to the fibrous sheet to form a pattern corresponding to the perforated pattern net, and then drying in a drying step to obtain a patterned bulky paper. The above object has been attained by providing a production method of the above.

[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 (paper machine) 1 shown in FIG.
A bulky paper manufacturing apparatus in which a pattern applying step including a steam blowing nozzle N and an opening pattern net 31 circulating along a part of the peripheral surface of the suction drum 34 is provided between a paper layer forming step and a drying step. 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 pattern applying section 30 includes a suction drum 3
4. An aperture pattern net 31 circulating along a part of the peripheral surface of the suction drum 34 and the steam spray nozzle N. A suction box 37 is provided in the suction drum 34.
Is provided. As shown in FIG.
7 is arranged inside a portion where the opening pattern net 31 runs along the peripheral surface of the suction drum 34, whereby the air flows from the outside toward the inside through the opening pattern net 31. Is made possible. A steam spray nozzle N is disposed outside the orbiting surface of the opening pattern net 31 so as to face the suction box 37 so that steam is blown over the entire width of the fiber sheet 2. It has been done. Further, the pattern applying 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. Is easy.

In the pattern applying section 30, the steam spray nozzle N is configured to spray steam at a predetermined temperature and a predetermined flow rate onto the fiber sheet 2. As described above, since the steam spray nozzle N is disposed so as to face the suction box 37,
In the present embodiment, the application of heat by spraying water vapor onto the fiber sheet 2 and the suction of the fiber sheet 2 are simultaneously performed.

In order to pattern the wet fibrous sheet 2 by suction, the above-described apertured pattern net 3 is used.
1. It is important to use a patterning process including the suction box 34 and the steam spray nozzle N. 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 aperture pattern net 31 is composed of an aperture pattern structure 32 and a reinforcing belt 33 for conveyance. The aperture pattern structure 32 is a plastic net produced by a melt extrusion molding method of a thermoplastic resin, and has a large number of circular apertures formed over the entire surface thereof, forming a mesh pattern. I have. The opening pattern structure 32 is integrated with the reinforcing belt for conveyance 33 by sewing.

The opening 35 in the opening pattern structure 32 shown in FIGS. 2A and 2B preferably has one area of 3 to 25 mm ² . If the area is 3 mm ² or more, the fiber is sufficiently deflected into the opening 35, and a good low-density projection (corresponding to a low-fiber-density region described later) is formed in the obtained bulky paper. be able to. Also,
When the thickness is 25 mm ² or less, it is possible to effectively prevent the fibers from dropping due to suction, prevent holes from being formed in the bulky paper, and further form a mesh-like high-density region (high fiber (Corresponding to the density region) can be sufficiently secured, and bulky paper having sufficient strength can be efficiently obtained.

The area of the opening 35 is related to the area ratio of the opening in the opening pattern structure 32, and the area of each of the openings 35 is preferably set in the above-mentioned range. The area ratio of the opening portion of the opening portion 35 is preferably 18 to 96% from the viewpoint of improving the absorption capacity, texture and strength of the bulky paper. The area ratio of the opening portion in the present specification refers to the area ratio of the opening portion 3 in the opening pattern structure 32.
The value measured for the area where 5 is formed,
For example, both left and right sides of the aperture pattern structure 32 where the aperture 35 is not formed are excluded from the measurement target area of the aperture area ratio.

The area of the opening 35 is the same as the width of the net component 36 (see FIGS. 2A and 2B) forming (surrounding) the opening 35 in the opening pattern structure 32. The individual areas of the apertures 35 are preferably set in the above ranges, and the minimum width of the component 36 in the planar direction (that is, when the aperture pattern structure 32 is viewed in a plan view) is reduced. It is preferably 0.1 to 5 mm from the viewpoint of improving the strength or texture of the bulky paper. In addition, the minimum width of the above-mentioned constituent material 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.

The thickness T (see FIG. 2B) of the opening pattern structure 32 is preferably 0.3 to 1.5 mm, more preferably 0.4 to 1.0 mm. preferable. When the thickness is 0.3 mm or more, the fiber can be sufficiently deflected into the opening 35, and it becomes easy to form good low-density projections in the obtained bulky paper. Further, if the thickness is 1.5 mm or less, it is possible to effectively prevent holes from being formed in the bulky paper.

The aperture pattern structure 32 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 structure 32
Preferably has a water repellency having a contact angle with water of 60 ° or more, particularly 75 ° or more. The contact angle was measured using a CONTACT ANGLEMETER CA-D manufactured by Kyowa Interface Science Co., Ltd. at a temperature of 25 ° C., after dropping 10 μl of water onto a small sample plate (76 mm × 26 mm) of an aperture pattern structure with a syringe, It was obtained by quick measurement.

The transport reinforcing belt 33 used integrally with the aperture pattern structure 32 has a large number of apertures 3.
3 ′ is formed, and the opening pattern net 31 is formed.
It is used to increase the strength of the steel. For this purpose, the tensile strength in the longitudinal direction (circumferential direction) of the reinforcing belt for conveyance 33 is preferably 20 kg / cm in terms of stable running of the opening pattern net in a paper machine or a processing machine.
Or more, more preferably 40 kg / cm or more. The tensile strength is determined from the measurement of the breaking strength using a tensile strength tester, and the conditions are as follows:
The distance between the chucks is 100 mm, and the tensile speed is 60 mm / min. In addition, the conveying reinforcement belt 33 has an area of one opening 33 ′ such that the passing air volume and the conveying air amount are sufficient to cause the fiber to deflect into the opening 35 of the opening pattern structure 32. In securing enough strength as a belt for
Preferably, it is 0.01 to ¹ mm ² . Further, the opening area ratio of the reinforcing belt for conveyance 33 is such that an air flow rate sufficient to cause deflection of the fiber into the opening 35 of the opening pattern structure 32 is obtained, and From the viewpoint of obtaining a sufficient strength as a transport belt, it is preferably 10 to 70%, more preferably 15 to 50%. Further, the above-mentioned reinforcing belt for conveyance 33 is made of
3 "has a minimum width in the plane direction of 0.05 to 1 mm, particularly 0.1 mm.
It is preferably 10 to 0.30 mm. As the transport reinforcing belt 33, a belt similar to a mesh belt made of a linear woven fabric and used as a normal transport belt for papermaking and processing is used.

In the present embodiment, the opening pattern structure 32 and the transport reinforcing belt 33 are integrated by sewing as described above. In addition, heat sealing and photosensitive resin are used. The integration is also performed by a method of forming the aperture pattern structure 32 using the same.

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.

Next, the moisture contained in the fiber sheet 2 is dehydrated by the suction box 22, and the moisture content of the fiber sheet 2 before being transferred to the patterning step, which is a downstream step, is reduced to a predetermined value. Value. The moisture content is set to 50 to 85% by weight of the weight of the fiber sheet 2 (that is, the weight in a wet state) in order to enable sufficient patterning of the fiber sheet 2 in the pattern applying step, and is preferably 65 to 75% by weight. By setting the moisture content in this range, the fiber orientation by suction is effectively performed, and the effect of increasing the temperature of moisture by applying heat is sufficient.

The fiber sheet 2 adjusted to a predetermined moisture content is separated from the paper layer forming belt 21 and the opening pattern structure 3 in the opening pattern net 31 is formed.
2 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. Accordingly, in the fiber sheet 2, a region located on the opening 35 in the hole pattern structure 32 (this region is referred to as “region A”) is, as shown in FIG. As a result, the suction box 37 has a convex shape with a thickness that increases into the inside of the opening 35 and increases toward the inside of the suction box 37. The region A is a region having a low fiber density where the fiber density of the constituent fibers is lower than before the suction. In this case, the reinforcing belt 3 for conveyance, which is finer than the opening pattern structure 32, is provided below the opening pattern structure 32.
3, the sharp increase in thickness (sudden decrease in density) in the area A is restricted by the reinforcing belt 33 for conveyance, and a large hole is formed in the area A or the fiber sheet 2 is removed. It will not break.

On the other hand, the portion of the fiber sheet 2 located on the component 36 of the aperture pattern structure 32 and its vicinity (this region is referred to as “region B”) is formed by the suction. Since it is pressed against the material 36 and compressed, its thickness becomes slightly smaller and its fiber density becomes slightly larger than before suction. That is, the area B is
The region has a relatively high fiber density with respect to the region A. Such a high fiber density region has an effect of suppressing the tendency of the tensile strength to decrease due to the low fiber density region in the obtained bulky paper. In particular, as described above, since the aperture pattern structure 32 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. I do.

Water vapor is sprayed on the fiber sheet 2 by the water vapor spray nozzle N together with the suction.
The fiber sheet 2 is given a calorie of 5 kcal / kg or more. As a result, the temperature of the water in the fiber sheet 2 rises, and the time until drying is shortened, so that the shape retention of the areas A and B is improved, and the areas A and B are sprayed by the steam pressure. Are easily formed, and the patterning on the fiber sheet 2 becomes clearer.
The amount of heat applied to the fiber sheet 2 is 5 kcal / kg
When the temperature is less than the above, the temperature of the water contained in the fiber sheet 2 does not rise sufficiently, and the fiber sheet 2 is not sufficiently patterned. A preferred range of the amount of heat applied to the fiber sheet 2 is 10 to 70 kcal / kg. In the present specification, the above-mentioned heat amount indicates the heat amount applied to 1 kg of the water-containing fiber sheet immediately before the heat amount is applied. The calorific value was calculated by calculating the specific heat of the pulp to 0.4 cal.
/ G, the specific heat of water is set to 1.0 cal / g, and is calculated based on the temperature difference of the fiber sheet 2 before and after passing through the calorific value imparting unit and the moisture content before passing through the calorific value imparting unit. That is, assuming that the moisture content of the fiber sheet 2 before passing through the heat application unit is x (% by weight) and the temperature difference before and after passing through the heat application unit is t (° C.), the heat amount Q applied to the fiber sheet 2 ( kcal / kg)
It is represented by the following equation. Q = {0.4 (1-x / 100) + x / 100} × t

The temperature and the flow rate of the steam blown to the fiber sheet 2 are not particularly limited as long as the amount of heat applied to the fiber sheet 2 is not less than the above-mentioned value. The temperature of the steam immediately after is preferably 100 ° C. or higher, and the flow rate is 2
It is preferably at least m / sec, particularly preferably at least 5 m / sec. In the present embodiment, the fiber sheet 2 is used.
Although steam spraying is used as a means for applying heat to the air, other means, such as hot air spraying, can be used. In this case, the temperature of the hot air should be 50 to 300 ° C, particularly 100 to 250 ° C. Preferably, the flow rate is 2 m
/ Sec or more, particularly preferably 5 m / sec or more. Further, the shorter the distance between the steam nozzle or the hot air nozzle jet port and the fiber sheet 2, the greater the amount of heat given to the passage flow velocity increases, but preferably 20 to 200 mm.

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 structure 32 is added to the fiber sheet 2. Patterning corresponding to the pattern is performed.

The suction force of the suction box 37 in the pattern applying step depends on the basis weight, moisture content, etc. of the fiber sheet 2;
-100 kPa, preferably -25 to -70
More preferably, it is kPa.

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

The fiber sheet is dried while the dryer 41 makes one rotation, and the bulky paper 3 as the final product is obtained.

As described above, according to the present invention, the pattern applying step including the suction section, the calorie applying section and the aperture pattern net is installed before the drying step, and the heat is applied near the suction section to form the pattern. A bulky paper which is more excellent in moldability and rich in bulkiness and absorbability can be obtained. The apparatus shown in FIG. 1 and the manufacturing method using the apparatus also have the advantages (1) to (4). (1) The opening pattern net 31 is provided with a suction drum 34
Because it only wraps around a part of the peripheral surface, there is no need to manufacture a long net. (2) 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. (3) Since the opening pattern net 31 is not guided into the drying process, it is hardly deteriorated even if it is used continuously for a long time, and its service life is extended. (4) The pattern providing section 30
By moving the entirety and removing the aperture pattern net 31 from the travel path of the fiber sheet 2, the production of normal paper can be facilitated, and switching to the production of normal paper is easy.

FIG. 4 schematically shows the cross-sectional structure of the bulky paper thus obtained. As shown in FIG. 4, the bulky paper 3 obtained by the above-described method has a region A having a low fiber density and a region B having a high fiber density. The region A is formed corresponding to the opening 35 in the opening pattern structure 32, and has a relatively large thickness. On the other hand, the region B is formed so as to correspond to the component 36 surrounding the opening 35 in the opening pattern structure 32, 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, high absorbency,
It becomes excellent in softness. Further, since the high-strength region B has a continuous mesh pattern, the bulky paper 3 also 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. Such short fibers include, for example, chemical pulp of softwood and hardwood, wood pulp such as semi-chemical pulp and mechanical pulp, mercerized pulp and crosslinked pulp obtained by chemically treating these wood pulp, non-wood fiber such as hemp and cotton, and the like. Cellulose fibers such as regenerated fibers such as rayon fibers; and synthetic fibers such as polyethylene fibers, polypropylene fibers, polyester fibers, and polyamide fibers. Among these fibers, it is preferable to use cellulosic fibers such as wood pulp, non-wood pulp and rayon fiber from the viewpoints of product cost, strength, suitability for papermaking and the like. In particular, wood pulp is more preferable from the viewpoint of product cost. These short fibers are preferably used in an amount of 50 to 100% by weight, more preferably 70 to 100% by weight, based on the whole fibers constituting the bulky paper 3.

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 added to the entire fiber in an amount of 50 to 50%. 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.

In the present invention, the water vapor spray nozzle N in the above-described embodiment is installed upstream or downstream of the suction box 37 with respect to the transport direction of the fiber sheet 2, and the suction by the suction box 37 is performed. Before or after the heat treatment, heat may be applied to the fiber sheet 2. Further, in place of the aperture pattern net in which the aperture pattern structure and the reinforcing belt for conveyance used in the above-described embodiment are integrated, an aperture pattern net including only one wire mesh belt is used. Is also good. 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 (patterning in inline) has been described as an example.
The paper obtained by the normal papermaking is once subjected to normal papermaking, and the paper is re-wetted to form a fiber sheet having the above-mentioned moisture regain. Then, a calorie providing unit is provided, and the aperture pattern net is circulated along the suction unit. The fibrous sheet may be patterned (off-line patterning) using an appropriate device. 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 apparatus for producing bulky paper, comprising: a suction unit, a calorie application unit, and a pattern application unit provided with an aperture pattern net that circulates along the suction unit before the drying step.

[0036]

The following examples illustrate the effectiveness of the present invention.

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 the opening pattern net 31 that circulates along a part of the peripheral surface of the suction drum 34, and is −46.5 by the suction box 37 provided in the suction drum 34.
Water vapor was sprayed from a water vapor spray nozzle N arranged on the outer periphery of the opening pattern net 31 so as to face the suction box 37 while being suctioned at kPa, and a predetermined pattern was applied to the fiber sheet. At this time, the amount of heat applied to the fiber sheet was 14.45 kcal / kg. FIG. 2A shows an example of the opening pattern net 31.
And (b) have a circular opening shape, one opening area is 7.1 mm ² , the opening area ratio is 65.3%, and the width of the component forming the opening is 0. 7mm, thickness 0.71m
m, a polypropylene resin net 32 produced by a melt extrusion molding method, and one opening area of 0.1 mm.
023 mm ² , opening area ratio 18.8%, reinforcement belt for conveyance (OS-80, manufactured by Nippon Filcon Co., Ltd.) 33 having a tensile strength of 67.7 kg / cm in the longitudinal direction integrated with a sewing process. Was. The contact angle of the polypropylene resin with water is 92 °, so that the fiber sheet 2 can be easily separated from the resin net 32. 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 .

Example ² A bulky paper having a basis weight of 22 g / m ² was manufactured in the same manner as in Example 1 except that the calorific value of 8.50 kcal / kg was applied to the fiber sheet by adjusting the flow rate of steam. .

Example 3 The amount of heat of 29.75 kcal / kg was imparted to the fiber sheet by adjusting the flow rate of water vapor, and the opening pattern net 31 was formed as shown in FIGS. 5 (a) and 5 (b).
A hole pattern structure 32 having a square hole shape as shown in FIG. 1 and made of a photosensitive resin (PVA and tetrazonium salt) coated with urethane resin is placed on a reinforcing belt for transportation (manufactured by Nippon Philcon Corp., OS -80) 33
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 above-formed one was used.

Example 4 The amount of heat of 32.30 kcal / kg was applied to the fiber sheet by adjusting the flow rate of water vapor, and only one wire mesh belt was used as the opening pattern net 31 using the suction box 37. -33k
Except for suctioning with Pa, the same operation as in Example 1 was carried out to obtain a basis weight of 22.
g / m ² bulky paper was produced. The wire mesh belt is a net formed by weaving a resin-made linear body (a plain-woven net in this embodiment), and has a large number of square openings 35 formed over the entire surface thereof. A pattern is formed. That is, one sheet fulfills the functions of the aperture pattern structure 32 and the transport reinforcing belt 33 in the first embodiment.

Example 5 The same steam blowing nozzle N sprayed hot air at 200 ° C.
A bulky paper having a basis weight of 22 g / m ² was produced in the same manner as in Example 4 except that a heat amount of 1.05 kcal / kg was applied.

[Comparative Examples 1 to 3] In Examples 1, 3 and 4, the same operation as in Examples 1, 3 and 4 was carried out, except that heat was not applied by steam, respectively, and the basis weight was 22 g / m 2.
^Two papers were each manufactured.

The production conditions of the above Examples and Comparative Examples are summarized in Table 1. Further, for the bulky paper of the above example and the paper of the comparative example, 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 on the plate.
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> Bulk paper is 7 cm × 7 cm.
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> The bulky paper was cut into strips 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.

[0051]

[Table 1]

[0052]

[Table 2]

As is evident from the results shown in Tables 1 and 2, the bulky papers (Examples 1 to 5) obtained by applying a specific amount of heat to the fiber sheet and sucking it were compared with the papers of Comparative Examples. It can be seen that the thickness is larger, the absorptivity is higher, and the strength is moderate as compared with.

[0054]

As described in detail above, according to the method for producing bulky paper of the present invention, by applying heat in the vicinity of the suction portion, the pattern formability is improved, and the bulky paper having rich bulkiness and absorptivity is obtained. Is obtained. In addition, the thickness is large, the absorbency is high,
A bulky paper having excellent softness and moderate strength can be obtained. 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, since the opening pattern net 31 is not guided into the drying process, it is hardly deteriorated even when 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 used in a first embodiment of a bulky paper manufacturing method 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 an enlarged view of a main part showing a state of suction of a fiber sheet by a suction drum.

FIG. 4 is a schematic view showing a cross-sectional structure of a bulky paper obtained by the method for manufacturing a bulky paper of the present invention.

FIG. 5A is a plan view showing another example of the aperture pattern net used in the first embodiment [FIG.
5 (b) is a cross-sectional view taken along line II of FIG. 5 (a) (equivalent to FIG. 2 (b)).

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 bulky paper manufacturing device 2 fiber sheet 3 bulky paper 10 raw material supply unit 20 paper layer forming unit 30 pattern imparting unit 31 aperture pattern net 32 aperture pattern structure 33 transport reinforcement belt 34 suction drum 35 aperture unit 36 component material 37 Suction box 40 Drying part 41 Drum through air dryer 50 Winding part A Low fiber density area B High fiber density area N Steam spray nozzle

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Yanagida 2606 Kabane-cho, Akaga-cho, Haga-gun, Tochigi Pref. In the Kao Corporation Research Institute Terms (Reference) 4L055 AJ05 BD04 BD20 CD01 CE62 CE90 EA13 FA16 GA26 GA29

Claims (4)

[Claims] 1. A method according to claim 1, wherein the pattern providing step includes an opening pattern net orbiting along the suction part.
% Of the fiber sheet is transferred, and the fiber sheet is sucked while being held on the opening pattern net.
Simultaneously with the suction or before and after the suction, the calorie application unit applies a caloric value of 5 kcal / kg or more to the fiber sheet to form a pattern corresponding to the aperture pattern net on the fiber sheet. A method for producing bulky paper, characterized by obtaining a bulky paper patterned by drying. 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 method according to claim 1, wherein the heat quantity is applied to the fiber sheet.
2. The method is performed by spraying steam or hot air.
4. The method for producing a bulky paper according to any one of claims 3 to 3.