JP2015196910A - Manufacturing method for corrugated board base paper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for corrugated board base papers with excellent strength and laminating property even in using recycled pulp as raw material pulp.SOLUTION: It is a manufacturing method that a paper stock containing raw material pulp including recycled pulp and polyacrylamide is used to make paper by using a shaking device in a wire part.

Description

  The present invention relates to a method for producing a corrugated cardboard.

  Corrugated cardboard is used as a packaging material in a wide range of industries because it can be mass-produced, is lightweight, can be folded, and can be recycled.

  Corrugated cardboards constituting the corrugated cardboard are classified into exterior liners / interior liners (exterior liners / interior liners are collectively referred to as liners; hereinafter the same applies in this specification) and core base papers. Corrugated cardboard is manufactured by forming a core base paper into a corrugated shape, applying an adhesive to the top of the core base paper, and bonding a liner thereto.

For the purpose of reducing raw material costs, waste paper pulp has been used for corrugated cardboard as one of the raw material pulps. In recent years, the ratio of waste paper pulp has increased significantly due to improvements in waste paper processing technology and sophistication of paper making equipment at cardboard base paper manufacturers.
Corrugated base paper is required to have strength from its application, but the strength decreases as the blending ratio of waste paper pulp increases. In particular, the waste paper distributed in the market in recent years has often undergone repeated recycling treatment, and when such waste paper is reused as waste paper pulp, it tends to be a pulp having a fiber length shorter than that of conventional waste paper pulp, Accelerating the decline.

As a countermeasure against the problem of such a decrease in strength accompanying an increase in the ratio of waste paper pulp, a means for blending a paper strength enhancer, particularly polyacrylamide, into the base paper may be employed.
Addition of polyacrylamide to the stock is believed to increase the number of hydrogen bonds between cellulose fibers and increase the strength of the paperboard corrugated paper.
Polyacrylamide is preferably used because it has a greater paper strength enhancing effect than other paper strength enhancers and there is no risk of thermal decomposition by a dryer of a paper machine.

  By blending polyacrylamide into the corrugated base paper, the strength of the base paper is improved, but there is a problem that the bonding property at the time of corrugated board production is lowered. This problem is considered to be caused by the low affinity between the polyacrylamide and the adhesive that bonds the core base paper and the liner. If corrugated base paper with poor bonding properties is fed to the corrugated board manufacturing process, partial or full bonding failure will occur, increasing the amount of adhesive used for bonding or reducing the bonding speed. It is necessary to take measures such as this, resulting in an increase in manufacturing cost and a decrease in manufacturing efficiency.

  With the increase in the ratio of used paper pulp, the addition rate of polyacrylamide, which is a paper strength enhancer, is also increasing, and the problem of a decrease in bonding properties is increasing as compared with the past.

  As described above, it is one of the problems to be solved for a corrugated baseboard manufacturer to produce a corrugated baseboard that is excellent in strength and bonding properties while using waste paper pulp as a raw material pulp.

As a method for solving such a problem, for example, Patent Document 1 discloses a method in which oxidized starch having a specific oxidation degree and a network-like water-soluble polymer are coated on the surface of a core base paper. .
Patent Document 2 discloses an invention in which a coating liquid mainly composed of a modified starch having a specific molecular weight range is applied to the surface of a liner that has been made to have a specific basis weight and a specific density. ing.

JP2012-219424A JP 2009-191212 A

However, when the inventor confirmed about the method disclosed in Patent Document 1, in the light-weight core base paper having a basis weight of less than 100 g / m ² , an improvement in strength and bonding property was recognized. In the case of 120 g / m ² or more, which is the main basis weight range of the base paper, no significant strength improvement effect was observed due to insufficient penetration of the surface coating liquid into the base paper.
In addition, with respect to the method disclosed in Patent Document 2, if the liner has a main basis weight range of 160 g / m ² or more, the surface coating solution may not be sufficiently penetrated into the base paper, or may be further improved in strength. Was not recognized.

  In view of the above circumstances, an object of the present invention is to provide a method for producing a corrugated base paper that is excellent in strength and bonding properties while using waste paper pulp as a raw material pulp.

The present invention solves the problem by the following means.
[1] A method for producing a corrugated cardboard, characterized in that a paper stock containing raw pulp containing waste paper pulp and polyacrylamide is made by using a shaking device in a wire part. Method.
[2] The method for producing a corrugated cardboard according to [1], wherein 80% by mass or more of waste paper pulp is contained in the raw material pulp based on the total dry mass of the raw material pulp.
[3] The method for producing a corrugated cardboard according to [1] or [2], wherein the basis weight of the corrugated cardboard is 100 g / m ² or more.
[4] The method for producing a corrugated cardboard according to any one of [1] to [3], wherein the shaking device is used in the range of shaking numbers 3,000 to 6,500.
[5] A method for producing a corrugated cardboard made by a pasting former, wherein the layer having the largest basis weight among the layers constituting the corrugated cardboard is described in any one of [1] to [4] A method for producing a corrugated cardboard, characterized in that it is produced by the above method.
[6] The method for producing a corrugated board according to any one of [1] to [5], wherein the corrugated board is a core base paper.

  According to the method for producing a corrugated cardboard of the present invention, it is possible to produce a corrugated cardboard excellent in strength and bonding properties while using waste paper pulp as a raw material pulp. In particular, in the production of corrugated base paper having a high content ratio of waste paper pulp, corrugated base paper having a desired strength can be produced without adding a large amount of paper strength enhancer to the stock.

Hereinafter, the manufacturing method of the corrugated cardboard of the present invention will be described in detail.
In the present specification, the term “corrugated cardboard” is used as a term including both the liner and the core core paper. As a matter of course, various terms and types of liner and core raw paper such as reinforced liner, coating liner, reinforced core base paper, and lightweight core base paper are also included in the term “corrugated base paper”.
In the present specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

<Preparation of paper stock>
Corrugated base paper is obtained by papermaking. The paper stock is prepared by adding a paper strength enhancer and, if necessary, other additives (filler, sizing agent, dye, etc.) to the raw pulp slurry.

(Raw pulp)
In the method for producing corrugated base paper of the present invention, waste paper pulp is used as the raw material pulp. As a blending example of the raw material pulp, it may be composed of substantially only waste paper pulp, or may be composed of waste paper pulp and pulp other than waste paper pulp.

  Although the amount of waste paper pulp in the raw material pulp is not particularly specified, it is preferable to include the used paper pulp in the raw material pulp in an amount of 80% by mass or more based on the total dry mass of the raw material pulp because the effect of the present invention is easily enjoyed. More preferably, the content is substantially 100% by mass. In general, the strength of a corrugated base paper having a high content ratio of waste paper pulp is likely to decrease. However, according to the production method of the present invention, the waste pulp contains 80% by weight or more in the raw pulp based on the total dry weight of the raw pulp. Although it is a corrugated cardboard, it is possible to suppress a decrease in strength. As a matter of course, even the waste paper pulp obtained from the waste paper that has been subjected to the recycling process a plurality of times can enjoy the effects of the present invention.

  The waste paper pulp is also called waste paper pulp obtained by dissociating corrugated paper, magazine waste paper, leaflet waste paper, newspaper waste paper, office waste paper, information paper waste paper, paper waste paper, etc., or waste paper pulp after these waste papers are deinked (DIP). ) Etc. can be used.

  Pulp other than waste paper pulp is virgin kraft pulp obtained by chemically treating wood and other fiber raw materials such as hardwood bleached kraft pulp, softwood bleached kraft pulp, hardwood unbleached kraft pulp, and softwood unbleached kraft pulp Alternatively, virgin mechanical pulp obtained by mechanically treating wood or chips, or virgin semichemical pulp obtained by combining mechanical treatment and chemical treatment can be used.

(Paper strength enhancer)
In the method for producing a corrugated base paper of the present invention, a paper strength enhancer is added to the raw pulp slurry. As the paper strength enhancer, polyacrylamide is used because it has a large paper strength enhancing effect.

Polyacrylamide is used for the purpose of improving the strength of corrugated base paper, particularly corrugated base paper containing waste paper pulp as raw pulp, and the purpose of use is the same in the present invention.
However, according to the method for producing a corrugated base paper of the present invention, it is possible to enjoy the strength improvement effect exhibited by polyacrylamide while overcoming the problem of reduction in bonding properties due to the use of polyacrylamide.
That is, the strength of the corrugated base paper is improved by the action of the shaking device described later, thereby making it possible to reduce the amount of polyacrylamide added to achieve the desired strength, resulting in a result. The bonding property of the corrugated cardboard is improved.

  The polyacrylamide may be an anionic polyacrylamide, a cationic polyacrylamide, or an amphoteric polyacrylamide.

As an anionic polyacrylamide, what introduce | transduced the carboxyl group as an anion group is mentioned as an example.
Examples of the cationic polyacrylamide include those in which an amine is introduced as a cationic group.
Examples of the amphoteric polyacrylamide include those obtained by introducing a carboxyl group into cationic polyacrylamide and those obtained by copolymerizing acrylamide, a cationic polymer, and an anionic polymer.

  The method of adding polyacrylamide to the raw pulp slurry may be a method of adding the raw pulp slurry before sending it to the head box (for example, a method of adding polyacrylamide to the inlet side of the fan pump). A method of adding the raw pulp slurry after feeding it to the head box (for example, a method of spraying polyacrylamide on the raw pulp slurry on the wire with a spray device) may be used.

  The amount of polyacrylamide added to the raw pulp slurry is not particularly specified in the method for producing a corrugated base paper of the present invention, but the amount added is reduced by 10% or more compared to the conventional method for producing a corrugated base paper. It is.

  In the limit which does not inhibit the effect of the present invention, paper strength enhancers other than polyacrylamide, such as starch, oxidized starch, carboxymethylated starch, cationized starch, vegetable gum, polyvinyl alcohol, carboxymethylcellulose, etc. The agent can also be used in combination with polyacrylamide.

(Other additives)
In the method for producing corrugated cardboard of the present invention, in addition to the paper strength enhancer described above, light calcium carbonate, heavy calcium carbonate, kaolin, talc, zeolite, aluminum silicate, magnesium silicate, magnesium carbonate, aluminum hydroxide, calcium sulfate. , Calcium sulfite, titanium dioxide, barium carbonate, silicon oxide, amorphous silica, urea-formalin resin, polystyrene resin, phenol resin, filler such as fine hollow particles, sizing agent such as alkenyl succinic anhydride, alkyl ketene dimer, dye Well-known chemicals such as antifoaming agents, preservatives, yield improvers, bulking agents, viscosity modifiers and the like can be added as appropriate to the slurry of raw material pulp alone or in combination.

<Paper making>
The prepared stock is supplied on the wire of the wire part by the head box. The supplied sample forms a paper layer on the wire. The formed paper layer is sent to the subsequent press part and dryer part and dried.

In the method for producing corrugated cardboard according to the present invention, the head box to be used is not particularly defined, and various head boxes can be used.
Specifically, a master jet (manufactured by IHI- Voith Paper Technology), a master jet with a module jet (manufactured by IHI- Voith Paper Technology), a BTF head box system (manufactured by Kawanoe Engineering Co., Ltd.), a shim flow head box ( A known head box such as Metso) or OptiFlow head box (Metso) can be used.

  The paper stock concentration in the head box is not specified in particular, but the lower the paper stock concentration is, the better the dispersibility of the pulp fibers. The material concentration is preferably 0.7 to 1.4% by mass.

In the method for producing a corrugated cardboard of the present invention, the form of the wire part to be used (former form) is not particularly defined, and various formers can be used.
Moreover, a single layer forming former may be used, and a combining former may be used.
Specifically, Duo Former D (made by IHI-Voit Paper Technology), Duo Former K (made by IHI-Voit Paper Technology), Duo Former KD (made by IHI-Voit Paper Technology), Duo Former Series Known formers such as Multiford Linear (IHI-Voit Perpay Technology Co., Ltd.), Ultra Former Series (Kobayashi Seisakusho), and Sim Former MB (Metso Co., Ltd.) can be used.

(Shaking device)
In the method for producing a corrugated cardboard according to the present invention, a shaking device (also referred to as a wire shake device) is introduced into a wire part, and paper is made using this.

The shaking device is a device that slides the breast roll of the wire part in a direction perpendicular to the flow direction of the stock (also referred to as a machine width direction).
The breast roll slides by applying a centrifugal force generated by rotating a weight body having an eccentric weight to the breast roll via the connecting rod.
As the breast roll slides, the wire also slides, but the stock on the wire receives a shearing force due to the sliding.

By using the shaking device, it is possible to reduce the amount of polyacrylamide added to obtain the desired strength of the corrugated board, and as a result, the bonding property of the corrugated board is improved.
This effect is presumed to be due to the fact that the use of a shaking device reduces the basis weight unevenness that tends to be a stress concentration point (destruction start point) and improves the burst strength of the corrugated cardboard. Further, it is presumed that the use of the shaking device causes the fibers to be oriented in the width direction (machine width direction), and the compressive strength in the lateral direction of the corrugated cardboard is improved.

In the method for producing a corrugated base paper of the present invention, the shaking device to be used is not particularly defined, and various kinds of shaking devices can be used.
Specifically, a known shaking apparatus such as Duo Shake (IHI-Voit Paper Technology) or Foam Master (Metso) can be used.

(Shaking number)
In general, a shaking number calculated by the following formula (1) is used as an index indicating the sliding energy of the shaking device.

I = f ² × s / V (1)

here,
I: Shaking number f: Frequency [cm ⁻¹ ]
s: amplitude [mm]
V: Paper making speed (wire speed) [m / min]

  A preferable range of the shaking number is 3,000 to 6,500, and more preferably 4,000 to 6,500. If the shaking number is equal to or greater than the lower limit, the effect of improving the burst strength and the compressive strength in the lateral direction is favorably exhibited. If the shaking number is less than or equal to the upper limit value, this effect can be enjoyed without applying an excessive load to the drive system of the shaking device.

(Shaking number setting)
As is clear from Equation (1), the shaking number can be set to the above-described preferable numerical range by changing at least one of the paper making speed (wire speed), the frequency of the shaking device, and the amplitude. it can. Usually, it is performed by changing the frequency or amplitude of the shaking device, not the paper making speed (wire speed).

  Based on the knowledge found by the inventor, when setting the shaking number outside the above-mentioned preferable numerical range to within the above-mentioned preferable numerical range, it is preferable to set the shaking number rather than changing the frequency of the shaking device. It is preferable to change and set the amplitude of the king device because the improvement in bursting strength and lateral compression strength is great even when the same shaking number is set.

  Furthermore, when changing the amplitude of the shaking device and setting the shaking number, it was found that the burst strength and lateral compressive strength are greatly improved when the amplitude is in the range of 20 to 30 mm. The reason is not clear, but if the amplitude is equal to or greater than the lower limit, it is considered that the effect of improving the basis weight unevenness and the fiber orientation in the lateral direction increase. If the amplitude is equal to or less than the upper limit value, this effect can be enjoyed without applying an excessive load to the drive system of the shaking device.

(Base paper layer for paper making using a shaking device)
When the corrugated base paper is made by a making former, it is preferable that the layer having the largest basis weight among the layers constituting the base paper is made using a shaking device. Of course, if it is allowed in view of installation space and introduction cost, it is preferable to make a plurality of base paper layers using a shaking device.

  After the paper layer is formed in the wire part, water is pressed and dried in the subsequent press part and dryer part.

In the method for producing a corrugated cardboard according to the present invention, the form of the press part to be used is not particularly specified, but the press part having a shoe press device is provided because it is excellent in water squeezing ability and can suppress a decrease in the bulk of the base paper. It is preferable to use it.
As the shoe press device, specifically, a known device such as Nipco Flex Press (IHI-Voit Paper Technology) or Shim Belt S Press (Metso) can be used.

In the method for producing corrugated cardboard of the present invention, the type of the dryer part to be used is not particularly specified, and a double deck dryer or a single deck dryer can be used alone or in combination.
If high-speed papermaking is realized, it is preferable to actively use a single deck dryer for each group of dryers.

<Coating>
In the method for producing corrugated cardboard of the present invention, the base paper dried through the dryer part is subjected to clear coating or pigment coating (also referred to as pigment coating) on the surface depending on the desired quality depending on the use of the base paper. Is given.

  The base paper surface to be coated is not particularly defined, and may be double-sided coating or single-sided coating. Moreover, it may be front / back differential coating in which different coating liquids are applied on each surface.

  Regardless of whether it is clear coating or pigment coating, the coating apparatus to be used is not particularly defined. Blade coater, 2-roll coater (also called an incline coater), gate roll coater, rod metering size press coater, blade A known coating apparatus such as a metering size press coater, a curtain coater, a bill blade coater, or a velbapa coater can be used.

  Using such a coating apparatus, coating may be performed on-machine or off-machine, but if manufacturing efficiency is important, it is preferable to perform coating on-machine.

When performing clear coating, the coating liquid which does not contain a pigment can be applied.
As the starch, various starches such as oxidized starch, enzyme-modified starch, and phosphate esterified starch can be used.
As the water-soluble polymer, water-soluble polymers such as polyacrylamide and polyvinyl alcohol can be used, but it is preferable not to use polyacrylamide because of the possibility of reducing the bonding property.
In addition to starch or water-soluble polymer, the clear coating liquid may contain a known chemical such as a dye, a water-resistant agent, a water-repellent agent alone or in combination as an auxiliary agent.

Although the coating amount in the case of performing clear coating is not particularly limited, it is preferable to apply 0.5 to 5.0 g / m ² per side.

When the corrugated base paper is a coating liner or the like and pigment coating is performed, a coating liquid containing a pigment and an adhesive can be applied.
Examples of pigments include heavy or light calcium carbonate, kaolin, talc, silica, satin white, white carbon, aluminum hydroxide, aluminum silicate, magnesium silicate, magnesium carbonate, titanium dioxide, and plastic pigments. Pigments can be used.
Adhesives include starches such as oxidized starch, enzyme-modified starch and phosphate esterified starch, protein such as casein, soy protein and synthetic protein, cellulose such as carboxymethylcellulose and hydroxyethylcellulose, and synthetic products such as polyvinyl alcohol. Synthetic rubbers such as styrene / butadiene copolymers and methyl methacrylate / butadiene copolymers, vinyl polymer adhesives such as vinyl acetate copolymers and acrylic copolymers can be used.
In addition to pigments and adhesives, the pigment coating solution contains known chemicals such as dispersants, antifoaming agents, preservatives, viscosity improvers, colorants, lubricants, water resistance agents, and pH adjusters. It can be appropriately contained alone or in combination as an auxiliary agent.

Although the coating amount in the case of performing pigment coating is not specifically limited, it is preferable to apply 2.0-20 g / m < ² > per side.

  The corrugated base paper that has been rewetted by applying clear coating or pigment coating is dried by a drying process subsequent to the coating process.

  The drying apparatus used in the drying step is not particularly defined, and known drying apparatuses such as an infrared drying apparatus, a hot air drying apparatus, a steam cylinder drying apparatus, and an electric heater drying apparatus can be used alone or in combination.

<Finishing process>
In the method for producing corrugated base paper of the present invention, a flattening process (also referred to as a calendar process) can be performed on a base paper that has been subjected to clear coating or pigment coating, or a base paper that has not been subjected to such coating.

  In the method for producing a corrugated base paper according to the present invention, there is no particular limitation on a flattening apparatus (also called a calendar), and known flattening apparatuses such as a machine calendar, a soft calendar, a super calendar, a multi-nip calender, a gloss calendar, and the like. Can be used alone or in combination.

  Various conditions such as the number of nips, the nip line pressure, and the surface temperature of the heating roll of the flattening apparatus are not particularly defined, and can be appropriately adjusted according to desired quality.

The corrugated cardboard thus obtained is once wound up as a large roll by a reel device.
Then, it is rewound to a predetermined width and length while removing a defective portion with a winder device to form a small roll.
Small rolls are packaged in a specified packaging, enter a product warehouse, and are shipped to a cardboard manufacturer.

In the method for producing a corrugated base paper according to the present invention, the basis weight of the corrugated base paper is not particularly defined, and the effect of the present invention can be enjoyed at any basis weight, but the effect is remarkably easy to enjoy, The basis weight is preferably 100 g / m ² or more, and more preferably 160 g / m ² or more. In general, when making a cardboard base paper having a high basis weight, the basis weight unevenness that becomes the stress concentration point (starting point of fracture) is more likely to occur. However, the basis weight unevenness can be suppressed.
The basis weight is a value measured in accordance with JIS-P8124 (2007). In the case of corrugated cardboard obtained by performing clear coating or pigment coating on the surface of the base paper, the coating amount is included. Basis weight.

  Further, in the method for producing a corrugated base paper according to the present invention, the type of corrugated base paper is not particularly specified, and the effects of the present invention can be enjoyed regardless of whether it is a liner or a core base paper. Since the emphasis is on, the effect can be remarkably enjoyed when the core base paper is manufactured.

<Manufacture of cardboard>
The corrugated board manufacturing process using the corrugated base paper obtained by the manufacturing method of the present invention is roughly divided into a bonding process for producing a corrugated board sheet and a box making process for producing a corrugated cardboard box.

  In the bonding step, the core base paper and the liner are bonded by a machine called a corrugator to produce a corrugated cardboard sheet cut to a predetermined size.

  Corrugated cardboard sheets are classified into single-sided corrugated cardboard sheets, double-sided corrugated cardboard sheets, double-sided corrugated cardboard sheets, and double-sided corrugated cardboard sheets depending on the structure, but the corrugated cardboard obtained by the production method of the present invention is any of the corrugated cardboard sheets. Can also be suitably used.

  The corrugated shape of the core base paper (also called flute) is classified into A flute, B flute, C flute, and E flute according to the height of the step and the number of steps per 30 cm, but according to the manufacturing method of the present invention. The obtained core raw paper can be suitably used for any corrugated shape.

  In the box making process, the corrugated cardboard sheet is printed, joined, punched, etc. to produce a corrugated cardboard box according to the application.

  Various known methods can be employed for the specific manufacturing process of corrugated cardboard (see, for example, “Paper Sales Engineering Series 4 Corrugated Cardboard, Paper Industry Times (issued in 1996)”).

Examples of the present invention are shown below, but the present invention is not limited to these examples.
In addition, these examples show the production examples of the core base paper among the corrugated base paper, but are not intended to exclude the liner from the corrugated base paper obtained by the present invention.

[Example 1]
<Manufacture of core base paper>
(Preparation of paper stock)
Polyacrylamide (Polystron 117, manufactured by Arakawa Chemical Industry Co., Ltd.) as a paper strength enhancer is added to the raw pulp slurry consisting of 100% by mass of used paper pulp at a rate of 0.9% by mass with respect to the total dry mass of the raw pulp. Was added as follows.
Further, the paper stock was prepared by adjusting the density so that the stock density in the head box was 1.0% by mass.

(Paper making)
The obtained stock was fed onto the wire part wire by a head box.
The wire part is a single-layer on-form former, and the bottom wire breast roll is slidable by a shaking device (Duoshake, manufactured by IHI- Voith Paper Technology).
With such a paper machine, paper was made under the conditions of a paper making speed (wire speed) of 375 m / min, a shaking device at a frequency of 270 cm ⁻¹ and an amplitude of 15 mm to form a paper layer.
Subsequently, water was pressed and dried by a press part and a dryer part, flattened by a machine calendar, and then wound by a reel to obtain a core base paper having a basis weight of 200 g / m ² .

[Example 2]
After obtaining the core raw paper in Example 1, the addition rate of polyacrylamide (Polystron 117, manufactured by Arakawa Chemical Industries, Ltd.) was reduced from 0.9% by mass to 0.8% by mass. The frequency was changed from 270 cm ⁻¹ to 300 cm ⁻¹ . Other manufacturing conditions remained the same as in Example 1. After confirming the convergence of the quality fluctuation with a basis weight / moisture meter (hereinafter referred to as BM meter), a core base paper having a basis weight of 200 g / m ² was obtained.

[Example 3]
After obtaining the corrugating medium in Example 2 was changed frequency of the shaking device from 300 cm ^-1 to 390cm ^-1. Other manufacturing conditions remained the same as in Example 2. After confirming the convergence of the quality fluctuation with a BM meter, a core base paper having a basis weight of 200 g / m ² was obtained.

[Example 4]
After obtaining the core raw paper in Example 3, the production conditions of Example 2 were once restored. Thereafter, the amplitude of the shaking device was changed from 15 mm to 25 mm. Other manufacturing conditions remained the same as in Example 2. After confirming the convergence of the quality fluctuation with a BM meter, a core base paper having a basis weight of 200 g / m ² was obtained.

[Comparative Example 1]
After obtaining the core raw paper in Example 4, the shaking device was stopped. Thereafter, the addition rate of polyacrylamide (Polystron 117, manufactured by Arakawa Chemical Industries) was increased from 0.8% by mass to 1.0% by mass. Other manufacturing conditions were the same as in Example 1. After confirming the convergence of the quality fluctuation with a BM meter, a core base paper having a basis weight of 200 g / m ² was obtained.

The core base paper obtained in each production example was evaluated by the following method, and the results are shown in Table 1.
The specific burst strength and the specific compressive strength were measured in accordance with JIS-P8111 (2007) under environmental conditions of a temperature of 23 ± 2 ° C. and a humidity of 50 ± 2%.

[Shaking number]
The shaking number was calculated by the above formula (1).

[Specific burst strength]
The specific burst strength (unit: kPa · m ² / g) was measured based on JIS-P8131 (2007).

[Specific compression strength]
Based on JIS-P8126 (2007), the specific compressive strength in the transverse direction (unit: N · m ² / g) was measured using a test piece parallel to the paper making direction.

[Adhesiveness]
The core base paper obtained in Examples and Comparative Examples was bonded to a liner with a corrugator. The pasting property with a corrugator was evaluated in three stages as follows. This evaluation was performed by a corrugator operator (21 years of experience).
○: The bonding state was good over the entire surface of the cardboard sheet.
Δ: There was a case where bonding failure was observed in a part of the cardboard sheet,
By temporarily adjusting the amount of adhesive applied and the bonding speed,
A good bonding state was obtained.
X: A bonding failure may be observed in a part of the cardboard sheet,
It was necessary to frequently adjust the amount of adhesive applied and the bonding speed.

As is clear from Table 1, it can be seen that the core base paper having both strength and bonding properties can be obtained by the method for producing a corrugated base paper of the present invention.
Moreover, it turns out that the preferable range of a shaking number exists in the range of 3,000-6,500.
Furthermore, the shake of the shaker is changed from the condition of the second embodiment by changing the frequency of the shaker to approximately 6,000, and the shake of the shaker is changed from the condition of the second embodiment. Comparing with Example 4 in which the number is set to 6,000, it can be seen that the latter has a greater improvement in strength.

Claims (6)

  A method for producing a corrugated cardboard, wherein a paper material comprising raw pulp containing used paper pulp and polyacrylamide is made using a shaking device in a wire part.   The method for producing a corrugated base paper according to claim 1, wherein the raw pulp contains 80% by mass or more of the waste paper pulp based on the total dry mass of the raw pulp. The basis weight of the corrugated cardboard is 100 g / m ² or more, The method for producing corrugated cardboard according to claim 1 or 2.   The method for producing a corrugated cardboard according to any one of claims 1 to 3, wherein the shaking device is used in the range of shaking numbers 3,000 to 6,500.   It is a manufacturing method of the corrugated board base paper made by the combining former, Comprising: The layer with the largest basis weight is manufactured by the method of any one of Claims 1-4 among the layers which comprise a corrugated board base paper. A method for producing a corrugated cardboard.   6. The method for producing a corrugated base paper according to claim 1, wherein the corrugated base paper is a core base paper.