JPH07238263A - Adhesion rate-increasing agent for corrugated boards and production process for corrugated boards using the same - Google Patents

Abstract

PURPOSE:To provide an adhesion rate-increasing agent which can effect high- speed lamination of the center core and the liners with no problem on handling safety and has the effect to prevent the corrugated sheet from being delaminated, and to provide the production process for corrugated boards using said agent. CONSTITUTION:The adhesion rate-increasing agent is prepared by dissolving borax in an aqueous alcohol comprising 5 to 150 pts.wt. of a polyhydric alcohol and 100 pts.wt. of water. In the production of corrugated boards, the above agent is coated on at least one of core's and liner's surfaces to be bonded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding speed improver used for manufacturing a corrugated board sheet and a method for manufacturing a corrugated board sheet using the bonding speed improver.

[0002]

2. Description of the Related Art Corrugated cardboard sheets are made of starch paste or PV on both sides of a corrugated core (corrugated).
It is manufactured by laminating a liner using an A-based adhesive.

In the production of this corrugated board sheet, the initial adhesive strength on the double facer side often affects the production rate, and the initial adhesive strength at the time of bonding differs depending on the type of liner or core.

In the manufacturing process of a corrugated cardboard sheet having a low initial adhesive strength, for example, when a shock is applied to a cutter portion or the like, there is a problem that peeling occurs from a bonding portion which is not yet sufficiently solidified. When using a base paper with poor laminating properties, the laminating speed must be reduced.

These problems are likely to occur during the production of, for example, water-resistant corrugated cardboard sheets, water-repellent corrugated cardboard sheets, thick ball sheets having low thermal conductivity, double-sided corrugated cardboard sheets, etc. Due to the difference
It often occurs due to lot variation.

Further, as a factor that influences the bonding speed of the core and the liner, there is a phenomenon called step cracking, which tends to occur when the bonding speed of the core and the liner is increased.

This step cracking is dealt with by increasing the strength of the core in the longitudinal direction, imparting slipperiness to the core, and the like. However, when the bonding speed between the core and the liner is increased. ,
The effect is not always sufficient.

From the above, at the production site of corrugated cardboard sheets, it is complicated to change the bonding conditions of the core and the liner during the operation. In addition, under the present circumstances, it is necessary to adopt operating conditions based on the laminating speed corresponding to the base paper that is likely to cause step cracks, and the disadvantage is that the production efficiency of corrugated board sheets is low.

In the production of corrugated cardboard sheets, in order to increase the bonding speed between the core and the liner, the bonding equipment and the glue used as a bonding agent have been improved, and by improving the base paper, Some efforts have been made to increase the initial adhesive strength and to obtain a corrugated cardboard sheet without step cracks.

The present inventors have proposed a method of applying borax to the bonding surface of a corrugated fiberboard base paper as a method for improving the initial adhesiveness in the production of a corrugated fiberboard sheet using an adhesive composed of starch or PVA. .

However, borax has a low solubility in water, and in order to coat the bonding surface of the corrugated cardboard base paper with a certain amount or more of borax, the borax solution must be coated in a large amount. The energy required for drying the coating liquid becomes large, which has the drawback of deteriorating productivity.

In order to solve this problem, paying attention to the high solubility of borax in an aqueous solution of caustic soda, a high-concentration borax solution containing an aqueous solution of caustic soda in which borax is dissolved is applied to form a coating of the borax solution. Although it has become possible to reduce the amount of working solution, caustic soda used as a dissolution aid for borax is a deleterious substance, so there is a problem in handling in terms of safety.

[0013]

In view of the above situation, the present inventors have found that polyhydric alcohols such as glycerin are extremely effective as borax dissolution aids in place of caustic soda, and completed the present invention. Came to do.

Further, the presence of polyhydric alcohol has the effect of increasing the solubility of borax and is also effective in preventing step cracks when applied to the core to be laminated on the liner. did.

Therefore, the object of the present invention is to improve the initial adhesive strength when the core and the liner are bonded together, so that the core and the liner can be bonded at a high speed and is safe. (EN) It is intended to provide a corrugated board sheet bonding speed improver having no problem in terms of properties and also having an effect of preventing step cracks, and a method of manufacturing a corrugated board sheet using the corrugated board sheet bonding speed improver.

[0016]

According to the present invention, borax is dissolved in a polyhydric alcohol aqueous solution containing 5 to 150 parts by weight of a polyhydric alcohol with respect to 100 parts by weight of water. It consists of a compound speed improver.

The present invention also comprises a corrugated board sheet bonding speed improver using glycerin and / or ethylene glycol as the polyhydric alcohol.

Further, according to the present invention, in the step of laminating the liner and the core, at least one of the joint surfaces of the liner and the core is coated with 5 to 150 parts by weight of polyhydric alcohol relative to 100 parts by weight of water. A method for producing a corrugated board sheet, which comprises coating a corrugated board sheet bonding speed improving agent in which borax is dissolved in an aqueous polyhydric alcohol solution.

Furthermore, the present invention comprises a method for producing a corrugated board sheet, which comprises using a corrugated board sheet bonding speed improver using glycerin and / or ethylene glycol as the polyhydric alcohol.

In the corrugated board sheet bonding speed improver of the present invention having the above-mentioned constitution, and in the method for producing a corrugated board sheet using the corrugated board sheet bonding speed improver, the polyhydric alcohol used as a borax dissolution aid is Examples thereof include ethylene glycol, glycerin, polyglycerin such as diglycerin and triglycerin, and the like. Among them, ethylene glycol and glycerin are used for the handling property such as the solubility of borax and the viscosity of the corrugated board sheet bonding speed improver Most preferred in terms.

The amount of polyhydric alcohol mixed with water is
Depending on the type of polyhydric alcohol, water 100
The amount of polyhydric alcohol is 5 to 150 parts by weight, preferably 5 to 70 parts by weight, and more preferably 5 to 45 parts by weight with respect to parts by weight.

This is because when the amount of polyhydric alcohol mixed with 100 parts by weight of water is less than 5 parts by weight, the solubility of borax is not improved so much, and when the amount of polyhydric alcohol mixed with 100 parts by weight of water exceeds 150 parts by weight. In addition, the viscosity of the solution becomes high, the workability of dissolving borax and the workability at the time of applying the bonding speed improver to the cardboard base paper are deteriorated, and the polyhydric alcohol that has penetrated into the cardboard base paper becomes This is because the equilibrium water content of the base paper is increased, which adversely affects the paper quality.

Since the polyhydric alcohol is more expensive than the above-mentioned caustic soda as the borax dissolution aid, it is preferable to keep the cost as low as possible.

As the corrugated board sheet bonding speed improving agent of the present invention, generally, borax is dissolved in an amount of about 5 to 50% by weight.

In the method for producing a corrugated board sheet according to the present invention, the corrugated board sheet bonding speed improver is applied to at least one of the joint surfaces of the liner and the core in an amount of borax of 0.05. It is preferable that the coating is performed so as to be about 5.0 g / m ² .

Furthermore, in the method for producing a corrugated board sheet according to the present invention, the polyhydric alcohol 5 consisting of glycerin and / or ethylene glycol is added to 100 parts by weight of water.
In a polyhydric alcohol aqueous solution containing 150 parts by weight, a corrugated board sheet bonding speed improver in which borax is dissolved in an amount of about 5 to 50% by weight is provided on at least one of the joining surfaces of the liner and the core. Depending on the amount of borax applied,
Most preferably, the coating is performed so as to be about 5.0 g / m ² .

The corrugated board sheet bonding speed improver of the present invention may be applied to the corrugated board base paper by any method such as coating, impregnation or spraying.

The corrugated board sheet bonding speed improver may be coated to some extent. This is because in the initial adhesion between the liner and the corrugated top of the corrugated fiberboard sheet, a constant adhesive strength is not required for each corrugated corrugated top, and the corrugated board sheet as a whole has a predetermined initial bonding strength. It is sufficient if the liner and the corrugated top of the core are bonded to each other as long as the cardboard sheet can withstand the impact of the slitter.

The application of the corrugated board sheet bonding speed improver is as follows.
The liner and / or the core may be applied in the papermaking step, or may be applied by a corrugator in the step of laminating the liner and the core.

In the production of a corrugated board using a corrugated board base paper coated with the corrugated board sheet bonding speed improving agent of the present invention, and in the method of producing a corrugated board of the present invention,
Starch and PV conventionally used to obtain corrugated board sheets
The adhesive such as A can be used as it is, and as the starch, it is preferable to use the stain hole adhesive used in most of the corrugated cardboard sheets.

[0031]

According to the corrugated cardboard sheet bonding speed improver of the present invention, the adhesive applied to the top of the corrugated cardboard reacts with the bonding speed improver previously coated on the corrugated cardboard base paper during the production of the corrugated cardboard sheet. By thus increasing the viscosity, the effect of improving the initial adhesive strength of the corrugated board sheet is extremely effectively achieved.

Therefore, in the method for producing a corrugated board sheet using the corrugated board sheet bonding speed improver of the present invention, the initial bond strength between the liner and the core is extremely improved.

In particular, when the double-sided corrugated board sheet or the double-sided double-sided corrugated board sheet is manufactured, the heat conduction from the hot plate is insufficient, as in the case of bonding between the inner liner and the step top of the center core. Therefore, the low initial adhesive strength at the time of bonding is extremely effective in the part that is the biggest neck in increasing the bonding speed of the liner and the core, and as a result, the corrugated board sheet is highly efficient. Can be produced in.

Further, since the corrugated board sheet bonding speed improver of the present invention comprises a solution having a high borax solubility, that is, a high borax concentration, the application capacity of the corrugated board sheet bonding speed improver can be reduced. For this reason, the amount of evaporated water in the drying step after application of the bonding speed improver is small, and the amount of solute deposited is small.

From these facts, the corrugated board sheet is not warped or wrinkled, and a large amount of energy is not required to evaporate the water content after the solution is applied. It is possible to maintain the same productivity as the productivity when not performing.

Furthermore, when the corrugated board sheet bonding speed improver of the present invention is applied to the core, the polyhydric alcohol in the bonding speed improver retains water and absorbs water, thereby providing a so-called step crack preventing effect.

[0037]

EXAMPLES The concrete constitution of the corrugated board sheet bonding speed improver of the present invention and the method for producing a corrugated board sheet using the corrugated board sheet bonding speed improver will be described based on Examples.

Example 1 Implementation of the corrugated board sheet bonding speed improver of the present invention by using a glycerin aqueous solution prepared by mixing 43 parts by weight of glycerin with 100 parts by weight of water to prepare a 20% by weight solution of borax. I got an example.

Examples 2 to 4 20% by weight solution of borax was prepared in the same manner as in Example 1 except that the amount of glycerin mixed with 100 parts by weight of water was changed as described in the predetermined column of [Table 1]. An example product of the corrugated board sheet bonding speed improving agent of the present invention was obtained.

Example 5 A glycerin aqueous solution prepared by mixing 43 parts by weight of ethylene glycol with 100 parts by weight of water was used to prepare a 20% by weight solution of borax to prepare a corrugated board sheet bonding speed improving agent of the present invention. Example products were obtained.

Comparative Example 1 A corrugated board sheet bonding speed improving agent for comparison was prepared by using a glycerin aqueous solution prepared by mixing 203 parts by weight of glycerin with 100 parts by weight of water to prepare a 20% by weight solution of borax. Obtained.

The corrugated cardboard sheet bonding speed improver for this comparison has a high liquid viscosity (200 cps: 20 ° C., B type viscometer), and the coating amount becomes too large in the coating operation on the corrugated cardboard base paper. Therefore, it cannot be used as a corrugated board sheet bonding speed improver.

Comparative Example 2 By using an aqueous glycerin solution prepared by mixing 2.2 parts by weight of glycerin with 100 parts by weight of water, a 5% by weight solution of borax was prepared to improve the bonding speed of corrugated board sheets for comparison. I got an agent.

Comparative Example 3 A corrugated board sheet bonding speed improving agent for comparison was prepared by using a caustic soda aqueous solution prepared by mixing 14.3 parts by weight of caustic soda with 100 parts by weight of water and adjusting a 20% by weight solution of borax. Got

Comparative Example 4 A corrugated board sheet laminating speed improving agent for comparison made of a 2% by weight aqueous solution of borax was obtained. The solubility of borax in water is 3.57 g / 100 g at 20 ° C.

The compositions other than borax in the corrugated board sheet bonding speed improvers of Examples 1 to 5 and Comparative Examples 1 to 3 are shown in [Table 1].

[0047]

[Table 1]

Example 6 2 g (we of the corrugated board sheet bonding speed improver of Example 1 was added to a water resistant liner "Honshu Paper Co., Ltd .: SRK280".
t) / m ² (0.4 g / m ² as borax) and after drying, the coated surface of the bonding speed improver of the water resistant liner and water resistant core “Hokuyo Paper Co., Ltd .: MMS200” And were subjected to a bonding test with a corrugator using a starch adhesive by the stain hole method.

In the laminating test, after laminating first at a normal standard laminating speed and confirming that there is no problem in initial adhesiveness,
The speed was increased until peeling occurred at the cutter portion, and the limit speed due to the initial adhesiveness was determined.

The adhesive (pin) strength of the laminated product was measured, and the liner coated with the laminating speed improver was sampled to measure the equilibrium water content and ring crush, which are important properties as a corrugated board base paper.

Example 7 Using the corrugated board sheet laminating speed improver of Example 2, a corrugated board sheet laminating test was conducted by the same steps as in Example 6 below.

Example 8 Using the corrugated board sheet bonding speed improver of Example 3, a corrugated board sheet bonding test was performed in the same process as in Example 6 below.

Example 9 Using the corrugated board sheet bonding speed improver of Example 4, a corrugated board sheet bonding test was performed in the same process as in Example 6 below.

Example 10 Using the corrugated board sheet bonding speed improver of Example 5, a corrugated board sheet bonding test was performed in the same process as in Example 6 below.

Example 11 2 g (wet) / m of the corrugated board sheet bonding speed improving agent of Example 1 was added to the core "Honshu Paper Co., Ltd .: SAMZ120".
After coating at a ratio of ² and drying, the coated surface of the bonding speed improver for the core and the liner "Honshu Paper Co., Ltd .: NRK220"
The bonding test with was carried out in the same manner as in Example 6.

The adhesive (pin) strength of the laminated product was measured, and the core coated with the laminating speed improver was sampled to measure the equilibrium water content and ring crush, which are important properties as a corrugated board base paper. .

In this example, excellent results were obtained in the effect of preventing step cracks.

Comparative Example 5 8 g (we) of the corrugated board sheet bonding speed improving agent of Comparative Example 2 was applied to a water resistant liner "Honshu Paper Co., Ltd .: SRK280".
t) / m ² (0.4 g / m ² as borax) was applied and dried, and then a corrugated board test was performed in the same process as in Example 6 below.

Since the corrugated board sheet bonding speed improver used in this comparative example has a low borax concentration due to the solubility of borax, a large amount of corrugated board sheet bonding speed improver must be applied. In addition, during the coating process of the corrugated board sheet bonding speed improver, it was necessary to reduce the speed for adjusting the moisture content of the base paper.

Comparative Example 6 Using the corrugated board sheet bonding speed improver of Comparative Example 3, a corrugated board sheet bonding test was performed in the same manner as in Example 6 below.

Since the corrugated board sheet bonding speed improver used in this comparative example uses caustic soda as a dissolution aid for borax, it must be handled with extreme caution. Comparative Example 7 20 g (w of the corrugated board sheet bonding speed improving agent of Comparative Example 4)
Et) / m ² (0.4 g / m ² as borax), except for applying the same procedure as in Example 6 below.
A bonding test of corrugated board sheets was performed.

Since the corrugated paperboard bonding speed improver used in this comparative example has a low borax concentration due to the solubility of borax, a large amount of corrugated paperboard bonding speed improver must be applied. In addition, it had to be slowed down to adjust the water content of the base paper during the coating process of the corrugated board sheet bonding speed improver.

Comparative Example 8 20 g (w) of the corrugated board sheet bonding speed improving agent of Comparative Example 4 was used.
Example 11 below, except that the coating was performed at a ratio of et) / m ^2.
A bonding test of a corrugated board sheet was performed by the same process as above.

Since the corrugated board sheet bonding speed improver used in this comparative example has a low borax concentration due to the solubility of borax, a large amount of corrugated board sheet bonding speed improver must be applied. In addition, during the coating process of the corrugated board sheet bonding speed improver, it was necessary to reduce the speed for adjusting the moisture content of the base paper.

Comparative Example 9 A corrugated board sheet bonding test was carried out by removing the corrugated board sheet bonding speed improving agent coating step from the process of Example 6.

[Table 2] shows the results of the bonding test of the corrugated board sheets of Examples 6 to 11 and Comparative Examples 5 to 9 described above.

The limit speed due to the initial adhesiveness was shown as a relative speed, while the limit speed due to the initial adhesiveness when the corrugated board sheet bonding speed improver of Comparative Example 9 was not used was 100.

[0068]

[Table 2]

Further, the speed of coating and drying steps of the bonding speed improver in the bonding test of the corrugated board sheets of Examples 6 to 11 and Comparative Examples 5 to 8 was improved by the bonding speed of Example 6. The relative speed is shown in [Table 3], even though the speed in the coating step of the agent is 100.

[0070]

[Table 3]

[0071]

By using the corrugated board sheet bonding speed improver of the present invention, an adhesive such as starch or PVA is applied to the step top of the core to bond it to the liner and borax. Since the increase in the viscosity of the adhesive due to the reaction is extremely high,
The initial adhesive strength between the liner and the core can be effectively improved.

Therefore, according to the method for manufacturing a corrugated board sheet using the corrugated board sheet bonding speed improving agent of the present invention, particularly the exit portion of the single facer, the cutter portion after exiting the hot plate (corrugated board sheet width (The part to be cut in the direction), the slitter part (the part to cut the corrugated board in the length direction), etc. of the conventional corrugated board that had to slow down the machine because the liner and the core were separated. Compared with the manufacturing method, the practical advantage of being able to increase the production speed is great.

Further, since the corrugated board sheet bonding speed improver of the present invention uses polyhydric alcohol as a borax dissolution aid, it is a powerful drug such as a corrugated board bonding speed improver using caustic soda as a dissolution aid. Since it does not use, it has an extremely excellent effect in handling.

Furthermore, in the method for producing a corrugated board sheet bonding speed improver of the present invention, when the corrugated board sheet bonding speed improver is applied to the core, the polyhydric alcohol in the bonding speed improver is used. The effect of preventing step cracks is obtained by the water retention and water absorption effects of.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Kohei Hamasaki 2-3-2 Higashishinozaki, Edogawa-ku, Tokyo 2-3-2 Honshu Paper Manufacturing Co., Ltd. (72) Inventor Katsuhiko Morimoto 2-3-3 Higashishinozaki, Edogawa-ku, Tokyo 2 Honshu Paper Co., Ltd.

Claims (4)

[Claims] 1. A corrugated board sheet bonding speed improving agent, characterized in that borax is dissolved in a polyhydric alcohol aqueous solution containing 5 to 150 parts by weight of a polyhydric alcohol with respect to 100 parts by weight of water. 2. The corrugated board sheet bonding speed improver according to claim 1, wherein the polyhydric alcohol in the corrugated board sheet bonding speed improver is glycerin and / or ethylene glycol. Combine speed improver. 3. In the step of bonding the liner and the core, at least one of the joint surfaces of the liner and the core has a polyhydric alcohol of 5 to 150 relative to 100 parts by weight of water.
A method for producing a corrugated board sheet, which comprises applying a corrugated board sheet bonding speed improving agent in which borax is dissolved in a polyhydric alcohol aqueous solution containing parts by weight. 4. The method for producing a corrugated board sheet according to claim 3, wherein the polyhydric alcohol in the corrugated board sheet bonding speed improver is glycerin and / or ethylene glycol. A method of manufacturing a corrugated cardboard sheet, characterized by: