KR101331233B1 - Papermaking method and papermaking machine - Google Patents

Abstract

The papermaking method of the present invention is carried out using a paper machine comprising a pump 1, a screen 2 downstream of the pump 1, and a head box 3 provided downstream of the screen 2. Downstream from the pump 1, an aqueous solution of a pressure-sensitive adhesive for papermaking, in which the concentration is 0.1 to 3.0% by weight, is added to the raw material pulp slurry before the contaminants are removed from the screen 2.

Paper Machine, Pump, Head Box, Screen, Pulp Slurry

Description

PAPERMAKING METHOD AND PAPERMAKING MACHINE}

The present invention relates to a papermaking method and a papermaking machine for reducing the amount of water required for the pressure-sensitive adhesive.

In general, the manufacture of paper is a pulp process in which a raw material pulp slurry is produced by a process such as cooking, washing, selection, and bleaching after forming chips from solid wood, and the raw material pulp slurry is wired from a head box. It is performed by supplying it above and dehydrating it, and going through the papermaking process which produces | generates paper by the process of subsequent press, drying, etc.

As a paper machine used for manufacture of paper, various types, such as a long paper machine, a long paper machine, and a short paper machine, are known. When producing low basis weight papers, such as a tissue and toilet paper using these paper machines, generally, the adhesive for papermaking for providing pulp dispersibility is used. At the time of use of the pressure-sensitive adhesive for papermaking, for example, in the case of polyethylene oxide, the viscosity is high even at low concentrations, and because of its sharpness, it is difficult to mix with the raw material pulp slurry, is dissolved in water, and the concentration is 0.01. As an aqueous solution which is about weight% or less, the thing adjusted to have a moderate viscosity is added to a raw material pulp slurry. In addition, the pulp dispersion effect is exhibited in the papermaking process by use of the adhesive for papermaking, and in the paper obtained as a finished product, the pulp fibers are uniformly dispersed, and the texture is excellent. Do. However, in the case of the polyethylene oxide pressure sensitive adhesive, when the shear strength of the strength is applied to the aqueous solution, the aqueous solution viscosity decreases and the dispersion effect by the papermaking adhesive is reduced, so that it is added between the screen and the head box so that a large shear force is not applied.

On the other hand, the quality of polyethylene oxide adhesives has improved in recent years. That is, high molecular weight of a polyethylene oxide adhesive is aimed at. The pulp dispersion effect of the polyethylene oxide-based adhesive for papermaking depends on its molecular weight. The higher the molecular weight, the higher the dispersing effect, but the higher the aqueous solution viscosity is, thus making it difficult to mix with the raw material pulp slurry. In fact, when used industrially, viscosity adjustment is performed by using a lot of water for dissolving or diluting more than conventionally. Polyethylene oxide-based papermaking adhesives are used in many papermaking companies, but there is a drawback that requires a lot of water, and in some cases, about one third of the whole water is used for the papermaking adhesive. In view of the recent environmental load reduction, there is a demand for a paper-based adhesive or a method of using the same that can suppress the amount of water used as much as possible. In addition, the present situation uses the technology of 40 years ago about the usage method.

Patent Document 1 discloses an adhesive for papermaking instead of polyethylene oxide, but is intended to improve papermaking performance such as dispersibility of paper fibers and texture or feel of paper obtained, and is not intended to reduce water usage. not.

Patent Document 1: Japanese Unexamined Patent Publication No. 2000-290892

DISCLOSURE OF INVENTION

This invention is made | formed in view of the said background art, and the adhesive effect falls even when a high molecular weight polyethylene oxide type adhesive is used by optimizing the density | concentration and addition place of the adhesive solution for papermaking added to a raw material pulp slurry. An object of the present invention is to provide a papermaking method and a papermaking machine capable of reducing the amount of water used more than ever while having a good texture.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining in order to solve the said subject, when the viscosity change by the shear of the polyethylene oxide aqueous solution was evaluated in various ways, it confirmed that it had little influence of the viscosity fall with respect to a shear at the predetermined concentration or more. By applying the result to papermaking, it was found that the amount of water used can be reduced even when using a high molecular weight polyethylene oxide pressure-sensitive adhesive, thereby completing the present invention.

That is, according to the first aspect of the present invention, there is provided a slurry supply means for supplying a raw material pulp slurry, a screen for removing contaminants from the raw material pulp slurry supplied by the supply means, and a head box provided downstream of the screen. A papermaking method using a papermaking machine, wherein an aqueous solution of a pressure-sensitive adhesive for papermaking is added at a concentration of 0.1 to 3.0% by weight with respect to the raw material pulp slurry before the impurities are removed from the screen, downstream from the slurry supply means. A papermaking method is provided.

According to the above papermaking method, even in the case of using a high molecular weighted polyethylene oxide pressure-sensitive adhesive, the solution concentration can be improved more than ever, and since the dilution of the paper-making adhesive stock solution is not required as before, the amount of water used is greatly increased. It can be reduced (in the past, since it was necessary to dilute to about 0.01 weight%, 10 times or more of water was needed for adhesive dilution than this invention). Therefore, a polyethylene oxide-based pressure-sensitive adhesive which has been polymerized more than conventionally can be used in the papermaking method, and the pressure of the adhesive can be reduced and the quality of the finished paper can be improved. In addition, since dispersion of the pressure-sensitive adhesive into the paper machine uses a high shear of the screen, its dispersibility is uniform as compared with the prior art, and the paper obtained as a finished product is uniformly dispersed in the pulp fibers and has an excellent texture. As described above, according to the present papermaking method, the performance of the adhesive for papermaking can be easily exhibited, and the load of wastewater treatment and regeneration related to the papermaking water can be reduced, and the paper quality can be improved.

In addition, in the papermaking method of the present invention, problems such as field-derived adhesives and viscosity unevenness of the solution due to the high shear of the screen and the ability to remove contaminants (foreign matters) are also simultaneously solved, so that defects such as paper breaking are greatly reduced. By reducing, the paper production state can be stabilized. Therefore, according to the papermaking method of this invention, the yield in paper manufacture is improved and production efficiency can be improved.

On the other hand, since the solution concentration of the adhesive for papermaking can be reduced more than ever, and the dilution equipment used for dilution of the adhesive stock solution for papermaking is not necessary, the equipment for the adhesive for papermaking can be reduced in size. Can be utilized.

In addition, the polyethylene oxide-based pressure-sensitive adhesive has a high dispersing effect, but in high-speed paper machine such as crescent former paper machine and twin wire paper machine in which high shear is generated, the aqueous solution of polyethylene oxide pressure-sensitive adhesive is sheared in the conventional addition method. Because of this, the viscosity is lowered, so the advantage is less and the use thereof is light. However, according to the papermaking method of the present invention, even if high shear is applied, the pressure-sensitive adhesive can be added by a very simple facility without impairing the dispersing effect of the pressure-sensitive adhesive, and the quality of the finished paper can be improved and the productivity can be improved.

Preferably, the pressure sensitive adhesive for papermaking is a polyethylene oxide pressure sensitive adhesive, and the viscosity of the 0.5 weight% aqueous solution of the pressure sensitive adhesive for papermaking is 400 to 1100 mPa · s.

According to a preferred embodiment of the present invention, the aqueous solution of the adhesive for papermaking is added to the raw material pulp slurry flowing through the pipe connecting the slurry supplying means and the screen.

According to another preferable embodiment of this invention, the aqueous solution of the said adhesive for papermaking is added with respect to the raw material pulp slurry before screen drum permeation in the said screen.

On the other hand, according to the second aspect of the present invention, there is provided a slurry supply means for supplying a raw material pulp slurry, a screen for removing contaminants from the raw material pulp slurry supplied by the supplying means, and a head box provided downstream of the screen. A papermaking machine comprising: a pressure-sensitive adhesive addition means for adding an aqueous solution of a pressure-sensitive adhesive for papermaking with a concentration of 0.1 to 3.0% by weight with respect to the raw material pulp slurry before the contaminants are removed in the screen. A paper machine is provided.

Preferably, said slurry supply means comprises a pump connected to an upstream side of said screen via piping.

Preferably, the pressure-sensitive adhesive addition means includes additional piping connected to a pipe connecting the screen and the pump.

Preferably, the screen has a housing having a slurry supply port and a slurry discharge port, a drum housed in the housing and having a plurality of slits and a plurality of blades rotating around the drum. A blade assembly, wherein the slurry supply port is in communication with the space between the housing and the drum, and the slurry outlet port is in communication with the space inside the drum.

Preferably, the housing further comprises a foreign material outlet communicating with the space between the housing and the drum.

Other objects, features and advantages of the present invention will become apparent from the description of the embodiments made based on the accompanying drawings.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Examples of the paper machine with a screen used in the present invention include a best former paper machine, a suction breasted paper machine, a crescent former paper, a twin wire paper machine and the like.

1 shows a schematic configuration of an apparatus X1 that can be used in the papermaking method according to the present invention. The apparatus (X1) has a pump (1), a screen (2), a head box (3) and a pipe (5) connecting them, and configured to produce paper from the raw pulp slurry by carrying out the papermaking method of the present invention. It is.

The pump 1 as a slurry supply means sends the raw material pulp slurry containing the pulp fiber produced | generated in the pulp process to the screen 2 through the piping 5 at the predetermined pressure.

The screen 2 removes contaminants contained in the raw material pulp slurry and makes uniform the dispersion of the raw material pulp slurry. In FIG. 1, the screen 2 is only schematically shown. A more detailed configuration of the screen 2 is shown in FIGS. 2 and 3.

That is, as shown in FIGS. 2 and 3, the screen 2 mainly comprises a housing 21, a lid 22, a screen drum 23, a blade assembly 24 and a drive motor 25. . The housing 21 is provided with the slurry supply port 21a, the slurry discharge port 21b, and the foreign material discharge port 21c. The inside of the housing 21 is partitioned by the lower partition plate 21d and the upper partition plate 21e. The lid 22 is swingably connected (opened and closed) via a hinge 26 with respect to the upper end of the housing 21.

The screen drum 23 has an inner cylinder portion 23a fixed to the lower partition plate 21d, an outer cylinder portion 23b fixed to the upper partition plate 21d so as to surround the inner cylinder portion 23a, and these inner cylinder portions. The top wall 23c which connects 23a and the outer cylinder part 23b is provided. The lower end opening of the outer cylinder part 23b communicates with the slurry discharge port 21b via the center opening part of the upper partition plate 21e. In addition, the outer cylinder part 23b is formed with a plurality of slits 23d extending in the axial direction at intervals in the circumferential direction, and the inner and outer spaces of the outer cylinder part 23b communicate with each other via these slits 23d. The direction in which the slit 23d extends may be the circumferential direction of the outer cylinder part 23b. The length of each slit can be selected suitably. In addition, in FIG.2 and FIG.3, although the width | variety of the slit is exaggerated for the convenience of illustration of drawing, it is actually finer than what was shown.

The blade assembly 24 is lowered from the support plate 24a around the support plate 24a positioned above the upper wall 23c of the screen drum 23 and the outer cylinder portion 23b of the screen drum 23. The blade 24b includes a plurality of blades (four in the illustrated embodiment) which are vertically lowered. As shown in FIG. 3, each blade 24b has a shape similar to a wing of an airplane, and is located in the vicinity of an outer cylinder portion 23b of the screen drum 23.

The drive motor 25 is fixed to the lower partition plate 21d, for example, and has an output shaft 25a extending through the inner cylinder portion 23a of the screen drum 23. The upper end of the output shaft 25a is connected to the center of the support plate 24a of the blade assembly 24. When the drive motor 25 is operated, the blade 24b rotates, for example, in the direction of the arrow A in FIG. 3.

When the raw material pulp slurry to which the adhesive for papermaking is added (it is mentioned later) via the slurry supply port 21a of the screen 2 is supplied, the raw material pulp slurry will rotate at the high speed of the blade 24b. By passing through the very narrow slit 23d of the screen drum 23 while receiving the contact pressure by the leading edge of, relatively high shear force acts on the pulp fibers contained in the raw pulp slurry. As a result, the pulp fibers are discharged through the slurry supply port 21a in a state in which the pulp fibers are uniformly dispersed in the slurry. On the other hand, contaminants (solids other than pulp fibers) contained in the slurry cannot pass through the slit 23d, and one end adheres to the outer surface of the outer cylinder portion 23b of the screen drum 23. However, since the negative pressure acts on the trailing edge side of the blade 24b, the adhered foreign matter is peeled off by the negative pressure action, falls off due to its own weight, and is discharged from the foreign matter discharge port 21c.

The head box 3 constitutes a part of the paper machine, and sprays a slurry (shown in the form of spots in the figure) on the endless running wire 4 as shown in FIG.

1, the piping 5a for adding the adhesive aqueous solution for papermaking is connected to the piping 5 which connects the pump 1 and the screen 2 to it. As the adhesive solution for papermaking to be added, an aqueous solution of polyethylene oxide is mentioned.

In the operation of the paper machine having the above configuration, the raw material pulp slurry is supplied by the operation of the pump 1. The raw material which passed the pump 1 is introduce | transduced into the piping 5. Here, about the raw material pulp slurry, the polyethylene oxide aqueous solution as an adhesive for papermaking is added via the piping 5a. This aqueous solution is prepared so that the density | concentration may become predetermined value in the range of 0.1-3.0 weight%. Although the preparation method of aqueous polyethylene oxide solution is not specifically limited, For example, what is necessary is just to melt | dissolve the powder of polyethylene oxide as an adhesive for papermaking in water, using the stainless dissolution tank provided with the stirring apparatus, stirring the inside of this dissolution tank. . In the piping 5, the raw material pulp slurry and the adhesive solution for papermaking are mixed, and this mixture (henceforth this mixture is called a "mixed slurry") is sent to the screen 2.

Although already explained, the mixed slurry is introduced into the screen 2 via the slurry supply port 21a shown in FIG. A relatively large shear acts on the mixed slurry firmly pressed to the outer cylinder portion 23b of the screen drum 23 by the high speed agitation of the blade 24b. This shearing removes contaminants contained in the mixed slurry and disperses the fibers. At the same time, in the aqueous adhesive solution for papermaking contained in the mixed slurry, the bonding of a part of the adhesive for papermaking is cut off, which leads to a slight decrease in viscosity, or sufficiently maintains the viscosity at which the pulp dispersion effect can be properly exhibited.

The mixed slurry, which is discharged from the screen 2 via the slurry outlet 21b, and the adhesive for papermaking is appropriately dispersed, is rectified by the head box 3 (FIG. 4) to continuously run the wire 4. Evenly sprayed on the stomach. The pulp fibers contained in the mixed slurry are uniformly dispersed by the pulp dispersion effect of the adhesive for papermaking on the wire 4. Thereafter, the mixed slurry is dewatered to produce paper as a finished product through various processes such as pressing and drying.

In the papermaking method according to the present invention, even a high molecular weighted polyethylene oxide-based adhesive for papermaking can be effectively used without impairing the original dispersion effect. That is, the amount of water required for dissolving and diluting the adhesive for papermaking which has been a defect in the past can be drastically reduced while using a polyethylene oxide adhesive. MEANS TO SOLVE THE PROBLEM The present inventors searched for the papermaking method in order to solve both the effective use method of the high molecular weight polyethylene oxide type papermaking adhesive which has a high papermaking effect, and the reduction of papermaking water which is a problem in a papermaking company. As a result, the high shear in the screen 2 is a high molecular weight polyethylene oxide-based papermaking adhesive, if the concentration (0.1 to 3.0% by weight) significantly higher than the papermaking adhesive concentration (0.01% by weight or less) generally added. It has been found that the adhesive for papermaking is efficiently dispersed in the raw material pulp slurry without impairing the dispersing effect even if caught.

In this papermaking method, the concentration of the aqueous adhesive solution for papermaking added to the raw material pulp slurry is 0.1 to 3.0% by weight. Preferably, it is 0.1 to 1.0 weight%, More preferably, it is 0.1 to 0.5 weight%.

When the concentration of the aqueous adhesive solution for papermaking to be added is less than 0.1% by weight, the effect of improving the pulp dispersion of the adhesive for papermaking decreases due to a decrease in viscosity due to shearing in the screen 2, so that the effect of improving the texture of the paper is sufficient. You won't do it. On the other hand, when the density | concentration of the adhesive liquid solution for papermaking added exceeds 3.0 weight%, since the viscosity of the adhesive liquid solution for papermaking is high, since it will not be fully mixed in the head box 3, the wire 4 In the above, the site | part which the adhesive aqueous solution for papermaking aggregates in a string form or a lump form is formed, and the dispersion of pulp fiber is inhibited. For this reason, there exists a possibility that defects, such as a paper break, generate | occur | produce, and paper manufacture cannot be performed stably. In addition, the resulting paper may have defects such as stains and perforations, which may cause deterioration of quality.

If the place where the adhesive for papermaking is added is lower than the screen 2, sufficient shearing force cannot be applied to the adhesive for papermaking, so that the adhesive for papermaking is not uniformly mixed with the raw material pulp slurry, and the papermaking adhesive as described above. It is necessary to form the site | part which the aqueous solution aggregates in a line shape or a lump shape, the dispersion of pulp fiber is inhibited, or the adhesive stock solution for papermaking is diluted, and it is necessary to adjust a viscosity. On the other hand, when the adhesive for papermaking is added upstream of the pump 1, when it passes through the pump 1, a larger shear is additionally given to the adhesive for papermaking, and a part of the bonds in the adhesive molecule are broken, thereby greatly widening. Since it leads to a decrease in viscosity, it is necessary to use a lot of adhesive for papermaking to obtain a production place of excellent texture. However, since the high shear force of the screen 2 can be used for uniform dispersion of the pulp fibers, downstream of the pump 1 and before the contaminants are removed from the screen 2, for example, the screen 2 The lid 2 of) may be opened, and the aqueous solution of the adhesive for papermaking may be directly injected into the housing 21.

As mentioned above, when the addition position of the adhesive for papermaking is selected suitably, and when the density | concentration of the aqueous adhesive solution for papermaking to add is 0.1-3.0 weight%, the high shear force in the screen 2 is used effectively, While the pulp dispersion effect is properly exhibited, not only the generation of defects such as stains and perforations can be prevented, but the amount of water used can be greatly reduced. Therefore, according to the papermaking method of the present invention, a paper having excellent texture can be obtained with a small amount of water consumption (i.e., low cost), and quality can be improved.

In addition, in the papermaking method of the present invention, by appropriate use of the adhesive for papermaking, defects such as paper breakage due to poor dispersion of pulp fibers can be reduced, and paper production can be stably performed. Therefore, according to this papermaking method, the yield in paper manufacture improves, and also it helps for the improvement of a production efficiency.

The adhesive for papermaking (polyethylene oxide) used in the papermaking method of the present invention has a 0.5 wt% aqueous solution viscosity of 400 to 1100 mPa · s, preferably 600 to 900 mPa · from the viewpoint of pulp dispersibility and handling. s is effective. The amount of the pressure-sensitive adhesive for paper making varies depending on the type of paper and is not particularly limited. However, 0.001 to 1.0%, preferably 0.01 to 0.5% is effective with respect to the dry weight of the paper produced.

Moreover, the papermaking method of this invention is used for manufacture of thin papers, such as tissues (typically about 5-15 g / m <2> basis weight) and toilet paper (typically about 5-30 g / m <2> basis weight) about 10-60 g / m <2> basis weight. It is preferable to apply, but it is not limited to this.

1 is a schematic structural diagram showing an example of an apparatus that can be used in the papermaking method according to the present invention;

2 is a longitudinal side view schematically showing the main portion of the screen;

3 is a transverse side view along line III-III of FIG. 2;

4 is a longitudinal side view schematically showing the main part of the head box;

Next, the Example of this invention is demonstrated, comparing with a comparative example.

Example 1

[Measuring Method]

Using the apparatus according to the above embodiment, paper was produced from the raw pulp slurry. In this embodiment, the best former paper machine was used as a paper machine, and it operated on the conditions which produce the tissue of 13 g / m <2> of basis weights at the initial speed of 1300 m / min (reel speed 1100 m / min). The papermaking raw material was made into a pulp slurry of 0.15% by weight using NBKP (softwood pulp) / LBKP (softwood pulp) = 40/60 (weight ratio) of 640 mlcsf (Canadian Standard Yeosu Island) at a high degree of beating. . As a pressure-sensitive adhesive for papermaking, polyethylene oxide (trade name: PEO-18Z, aqueous solution viscosity 430 mPa · s (0.5%), product of Sumitomo Seika Co., Ltd.) was used. 0.5 wt% aqueous polyethylene oxide solution was prepared. This polyethylene oxide aqueous solution was added to the piping 5 between the pump 1 and the screen 2, and papermaking was carried out. The usage-amount of the adhesive for papermaking was 0.14% as a weight ratio with respect to the dry weight of the produced paper.

[Evaluation of the Texture of Paper]

About the paper obtained by the said papermaking method, the improvement effect of a texture was evaluated. The evaluation was carried out by visual determination, and pulp fibers were uniformly dispersed, and there was no puncture, agglomeration parts of the pulp fibers, and the like, and the texture improvement effect was large. It is assumed that pulp fibers are uniformly dispersed, hardly punched or aggregated parts of pulp fibers, and have a large texture improving effect. ? Which hardly shows a texture improvement effect; Perforations, aggregates of pulp fibers, and the like were conspicuous, resulting in deterioration of texture, or papermaking defects such as paper breaking. Table 1 shows the results of confirming the texture and the amount of water used for the paper obtained by the present example.

[Measurement of Viscosity Aqueous Solution for Papermaking]

The aqueous solution viscosity of the polyethylene oxide type | system | group paper adhesive used for this invention was measured as follows. A commercially available 1 L glass beaker was filled with 500 g of pure water, and the pure water was stirred at a rotational speed of 240 rpm with a stirrer having a flat blade of 25 mm in length and 80 mm in width. 2.5 g of polyethylene oxide type | system | group paper adhesives were mixed carefully so that no field may arise here, and it stirred for 3 hours and melt | dissolved after that. Viscosity measurement was carried out using a B-type rotational viscometer manufactured by Tokimec Co., Ltd., to read the value after measurement for 3 minutes at a rotational speed of 12 rpm to determine the aqueous solution viscosity. In addition, the polyethylene oxide type aqueous solution used for the measurement used the thing made into the constant temperature of 25 degreeC previously.

Example 2

In this example, a polyethylene oxide (trade name: PEO-27, manufactured by Sumitomo Seika Co., Ltd.) having a viscosity of 720 mPa · s of 0.5 wt% aqueous solution was used as the adhesive for papermaking. Papermaking was carried out under the same conditions as in Example 1 except for the type of adhesive for papermaking. The usage-amount of the adhesive for papermaking was 0.11% as a weight ratio with respect to the dry weight of the produced paper. Table 1 shows the results of confirming the texture and the amount of water used for the paper obtained by the present example.

Example 3

In the present Example, papermaking was carried out under the same conditions as in Example 2 except that 0.1 wt% was used as the adhesive for papermaking. The usage-amount of the adhesive for papermaking was 0.13% as a weight ratio with respect to the dry weight of the produced paper. Table 1 shows the results of confirming the texture and the amount of water used for the paper obtained by the present example.

Comparative Example 1

In this comparative example, papermaking was carried out under the same conditions as in Example 1 except that 0.05 wt% was used as the adhesive for papermaking. The usage-amount of the adhesive for papermaking was 0.20% as a weight ratio with respect to the dry weight of the produced paper. Table 1 shows the results of confirming the texture and water usage of the paper obtained by this comparative example.

Comparative Example 2

In this comparative example, the addition place of the adhesive for papermaking was made between the screen 2 and the head box 3, and the addition density | concentration of the adhesive for papermaking was performed at 70 ppm. It paper-made on the conditions similar to Example 1 except the addition place and addition concentration of the adhesive for papermaking. The usage-amount of the adhesive for papermaking was 0.14% as a weight ratio with respect to the dry weight of the produced paper. Table 1 shows the results of confirming the texture and water usage of the paper obtained by this comparative example.

Comparative Example 3

In this comparative example, the addition place of the adhesive for papermaking was performed between the screen 2 and the head box 3. It paper-made on the conditions similar to Example 1 except the addition place of the adhesive for papermaking. The usage-amount of the adhesive for papermaking was 0.14% as a weight ratio with respect to the dry weight of the produced paper. Table 1 shows the results of confirming the texture and water usage of the paper obtained by this comparative example.

Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Adhesive addition place Between pump (1) and screen (2) Between the screen (2) and the head box (3) Pressure-sensitive adhesive concentration [%] 0.5 0.5 0.1 0.05 0.007 0.5 Use adhesive 0.5% aqueous solution viscosity [m [· s] 430 720 720 720 430 430 Amount of adhesive added (ratio [%] to dry weight of finished paper 0.14 0.11 0.13 0.2 0.14 0.14 Texture ◎ ◎ ◎ ○ ○ × Water content of pressure-sensitive adhesive [㎥ / D] 20.1 15.8 93.6 288 1441 20.1

In Examples 1 to 3, by improving the molecular weight, the aqueous solution concentration, and the place of addition of the pressure-sensitive adhesive for papermaking to be added within a predetermined range, the improvement effect on the amount of water used was large compared to Comparative Example 2, which is generally known in the art. . Moreover, in the method of this invention, since the dispersibility of an adhesive has improved more than ever by the front end of the screen 2, the texture of the obtained finished paper was improved compared with the conventional method.

When the addition concentration of polyethylene oxide was low like the comparative example 1, since the viscosity of the adhesive aqueous solution was low, the adhesive aqueous solution caused the viscosity fall by the shearing in the screen 2, and the adhesive usage increased notably.

As in Comparative Example 3, when the pressure-sensitive adhesive addition place adds a high concentration of aqueous adhesive solution for papermaking between the screen 2 and the head box 3, at the front end in the head box 3 that is relatively weaker than the front end of the screen 2. As the pressure-sensitive adhesive could not be uniformly dispersed in the raw material pulp slurry, a noticeable drop in texture was confirmed.

Claims (10)

A papermaking method using a papermaking machine comprising a slurry supply means for supplying a raw material pulp slurry, a screen for removing contaminants from the raw material pulp slurry supplied by the supply means, and a head box provided downstream of the screen. The papermaking method further downstream of the said slurry supply means is added with the aqueous solution of the polyethylene oxide type adhesive for papermaking whose density | concentration is 0.1-3.0 weight% with respect to the raw material pulp slurry before a contaminant is removed from the said screen. The papermaking method according to claim 1, wherein the 0.5 wt% aqueous solution viscosity of the adhesive for papermaking is 400 to 1100 mPa · s. The papermaking method of Claim 1 which adds the aqueous solution of the said polyethylene oxide type adhesive for papermaking with respect to the raw material pulp slurry which flows through the piping which connects the said slurry supply means and the said screen. The papermaking method of Claim 1 which adds the aqueous solution of the said polyethylene oxide type adhesive for papermaking with respect to the raw material pulp slurry before screen drum permeation in the said screen. In a paper machine comprising a slurry supply means for supplying a raw material pulp slurry, a screen for removing contaminants from the raw material pulp slurry supplied by the supply means, and a head box provided downstream of the screen, And a pressure-sensitive adhesive addition means for adding an aqueous solution of polyethylene oxide-based pressure-sensitive adhesive for papermaking with a concentration of 0.1 to 3.0% by weight relative to the raw material pulp slurry before the contaminants are removed in the screen. 6. The paper machine according to claim 5, wherein said slurry supply means includes a pump connected to an upstream side of said screen via a pipe. 6. The paper machine as claimed in claim 5, wherein said pressure sensitive adhesive adding means comprises additional piping connected to the piping from said slurry supply means to said screen. 7. The paper machine according to claim 6, wherein said pressure-sensitive adhesive adding means includes an additional pipe connected to a pipe connecting the screen and the pump. 6. The blade assembly of claim 5, wherein the screen comprises a housing having a slurry inlet and a slurry outlet, a drum housed in the housing, the drum having a plurality of slits, and a plurality of blades rotating around the drum. Wherein the slurry supply port is in communication with the space between the housing and the drum, and the slurry outlet port is in communication with the space inside the drum. The paper machine according to claim 8, wherein the housing further comprises a foreign material outlet communicating with a space between the housing and the drum.

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