JP2003201454A - Aqueous adhesive, method for producing the same, and corrugated board and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous adhesive in which the amount of a boron compound used is reduced or the boron compound is not used and to provide a corrugated board not containing borax by using the aqueous adhesive. <P>SOLUTION: The aqueous adhesive comprises water, a starch and thickening polymer compound(s). The starch is contained in total amount of 15-30 wt.% expressed in terms of solid content, based on total amount of the aqueous adhesive and the starch swollen by a swelling agent is contained in an amount of 5-25 wt.% based on total amount of the starch. The thickening polymer compound or compounds are selected from a water-soluble polymer compound and a synthetic resin emulsion which develop thickening property in water. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive used in the production of paper products such as corrugated board, and more particularly, to an aqueous adhesive suitable for a paste for corrugated board, a method for producing the same, and the aqueous adhesive. The present invention relates to a corrugated board to be manufactured and a manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, water, starch, borax (sodium tetraborate decahydrate), and boron compounds such as boric acid have been used as adhesives for manufacturing paper products such as paper containers and corrugated board. It is known that the above-mentioned starch contains an aqueous adhesive containing starch which has been swollen by a swelling agent and starch which has not been swollen, and this aqueous adhesive is widely used in the field of corrugated board production.

The above-mentioned boron compound is an excellent additive that exerts sufficient adhesive force in the above-mentioned water-based adhesive, but on the other hand, the "PRTR method (to the environment of specified chemical substances) enforced from April 2001. The Act on Understanding the Emissions and Promoting Improvements in Management) ”is certified as a chemical substance that may be harmful to human health and the ecosystem, and the operator releases the above-mentioned boron compounds into the environment. It became obligatory to report the amount and transfer amount in waste to the administrative agency.

The legal purpose of the PRTR law is to reduce the risk to the environment, and it is expected that the use will be prohibited in the future. Further, in recent years, interest in environmental protection has been increasing, and it is desired not to use the above-mentioned chemical substances having an environmental risk or to reduce the usage amount.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned matters, and a novel aqueous adhesive which further reduces the amount of the boron compound used or does not use the boron compound and borax containing the same. The challenge is to provide cardboard that does not contain such substances.

[0006]

Means for Solving the Problems As a result of studying a substitute for the boron compound in the water-based adhesive, the present inventors have found that
It was found that an aqueous adhesive having the same performance as that of the above-mentioned boron compound can be obtained when a thickening polymer compound is used, and the present invention has been completed.

That is, the present invention is an aqueous adhesive containing water, starch, and a thickening polymer compound, and a method for producing the same. The starch can be used in the same manner as a conventional water-based adhesive using a boron compound. The viscosity increasing polymer compound is one or more selected from water-soluble polymer compounds and synthetic resin emulsions that exhibit viscosity increasing in water. The present invention also relates to a corrugated board using the water-based adhesive and a method for manufacturing the same.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The water-based adhesive of the present invention is an aqueous adhesive containing water, starch and a thickening polymer compound, and the thickening polymer compound exhibits thickening properties in water. One or two or more selected from water-soluble polymer compounds and synthetic resin emulsions.

The starch used in the present invention contains a part of swollen starch, similar to the conventional aqueous adhesive using a boron compound. In the present invention, any commonly used starch can be used without particular limitation, so-called ordinary starch such as corn starch may be used, or a starch of a chemical product in which physical properties such as viscosity and water retention are adjusted. May be used. A swelling agent is usually used for swelling starch.

The swelling agent used in the present invention is not particularly limited as long as it swells starch in water. Examples of such a swelling agent include those that break the hydrogen bond, such as dimethyl sulfoxide, liquid ammonia, an alkaline solution, and a sodium rhodanate solution. In particular, using an alkali such as sodium hydroxide, potassium hydroxide, or calcium hydroxide as a swelling agent increases the alkalinity of the water-based adhesive, and when the water-based adhesive is applied to the surface of the paper, the water content of the paper is reduced. It is preferable because it is easy to transfer and the adhesive force is rapidly developed after application.

The swollen starch has a viscosity,
Prevents the separation and settling of other starch (hereinafter also referred to as "non-swollen starch") in the adhesive and contributes to improve the water retention of the adhesive by bonding the adhesive surface and the non-swollen starch during bonding. To do. The non-swelling starch instantaneously absorbs the water contained in the adhesive and the water contained in the swollen starch, and contributes to maintain the bonded state.

From such a point of view, in the present invention, the total amount of starch is 15 based on the total amount of the aqueous adhesive in terms of solid amount.
~ 30 wt% is used. Of these, the swollen starch is
It is contained in an amount of 5 to 25% by weight based on the total amount of starch. If the total amount of starch and the content of swollen starch are smaller than the above range, the above-mentioned action may not be sufficiently exhibited, and if it is larger than the above range, the viscosity becomes too large and it becomes difficult to handle, and sufficient adhesive force is exhibited. In some cases, the fluidity of the adhesive may be reduced, making it difficult to handle.

The thickening polymer compound is a polymer compound that exhibits thickening properties in water, and contributes to further developing and enhancing the above-mentioned water retention, colloidal property, thickening property, and thixotropic property. Boron compounds such as borax that have been conventionally used are considered to exhibit the above-mentioned physical properties such as water retention by binding to swollen starch in an aqueous adhesive by a crosslinking reaction. On the other hand, the viscosity-increasing polymer compound used in the present invention is not known so far as to the causal relationship with the microscopic state and action in the aqueous adhesive, but mainly in the aqueous adhesive. It is presumed that it is present around starch due to its affinity with starch, and it is speculated that it exhibits the same physical properties as the above-mentioned boron compound.

In the present invention, as such a thickening polymer compound, one or more kinds of a water-soluble polymer compound exhibiting a thickening property in water and a synthetic resin emulsion exhibiting a thickening property in water are used. . The thickening polymer compound used in the present invention may be a commercially available product, a synthetic product, or an extract from a natural product.

Examples of the water-soluble polymer compound include carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, carrageenan, guar gum,
Specific examples include pectin, sodium alginate, carboxylated starch, polyvinyl alcohol, and sodium polyacrylate.

Specific examples of the synthetic resin emulsion include alkali-soluble acrylic emulsion.

Among them, the thickening polymer compound is preferably a natural polymer from the viewpoint of environmental protection because it is easily decomposed by microorganisms. The thickening polymer compound is
It is preferable that it can be used for foods from the viewpoint of application to paper containers for foods. Examples of such a preferred thickening polymer compound include carboxymethyl cellulose,
Examples thereof include methyl cellulose, hydroxyethyl cellulose, carrageenan, guar gum, pectin, sodium alginate, and carboxylated starch. Further, the thickening polymer compound is preferably a polysaccharide or a derivative thereof, and further a cellulose derivative from the viewpoint of good affinity for the liner and the core in the production of corrugated board.

The viscosity-increasing polymer compound used in the present invention is different in type and physical properties, viscosity increase in water, degree of polymerization, affinity with starch, type and amount of swelling agent, gelling agent and crosslinking agent described later. The blending amount varies depending on various conditions such as the combined use of, and it is preferable to determine the blending amount of the thickening polymer compound according to these conditions. If the compounding amount of the thickening polymer compound is too small, it may not function sufficiently as an adhesive due to insufficient physical properties such as water retention as described above.
If the compounding amount of the thickening polymer compound is too large, it may gel and may not function as an adhesive.

An example of blending when the thickening polymer compound is used alone is as follows. When carboxymethylcellulose is used as the thickening polymer compound, the blending amount of carboxymethylcellulose varies slightly depending on the physical properties of carboxymethylcellulose. It is preferably about 0.1 to 0.7% by weight based on the total amount of the water-based adhesive. In addition, the substitution degree of the carboxymethyl group (hereinafter referred to as “D
Abbreviated as "S") is preferably 0.5 to 2.0, more preferably 0.5 to 1.5. Furthermore, the viscosity of a 1% aqueous solution of carboxymethyl cellulose is 100 to 1000.
0 mPa · s is preferable, and more preferably 100 to 50.
It is 00 mPa · s.

The water-based adhesive of the present invention may further contain additives such as a gelling agent and a cross-linking agent in order to further improve the function of the adhesive. As the gelling agent or crosslinking agent,
There is no particular limitation as long as it reacts with at least one of starch and a thickening polymer compound to form a crosslinked structure. For example, a polyvalent metal salt conventionally known (particularly preferably PRTR among polyvalent metal salts is preferable. Substances that do not conflict with the law) etc.

The above-mentioned additives mainly functionally supplement the above-mentioned thickening polymer compound, and the compounding amount thereof is such that the kind and physical properties of the additive to be used, the kind of thickening polymer compound to be used, and the type of the manufactured product. Depending on the application of the water-based adhesive and the required performance, the total amount of water-based adhesive is 0.
It is preferably about 001 to 1% by weight. If the compounding amount of the additive is too small than the above range, the effect of the additive may not be sufficiently expressed, and if it is more than the above range, it inhibits the action of the thickening polymer compound and adversely affects the dosage form and the like. May be affected.

In the present invention, other additives may be added in addition to the above-mentioned additives. As such other additives,
As conventionally known, urea resin, ketone resin,
Examples thereof include waterproofing agents such as anionic acrylic resins, antifoaming agents such as silicone oil, and preservatives such as isothiazolone chloride, isothiazolone, and bromonitroalcohol.

The water-based adhesive of the present invention uses the stain hole method known as a conventional method for producing a water-based adhesive containing a boron compound such as borax described above, and the boron compound is used in the stain hole method. It can be manufactured by using a thickening polymer compound instead.

That is, the method for producing the water-based adhesive in the present invention comprises the steps of swelling starch in water, dispersing starch in water containing swollen starch, initial addition water, water containing swollen starch, And a step of uniformly dispersing the thickening polymer compound in water containing unswollen starch and at least one of water containing swollen starch and unswollen starch.

The step of swelling the starch in water may be, for example, the step of swelling the starch using the swelling agent, or the step of swelling the starch by heating the water containing the starch. However, both steps may be adopted.

The step of dispersing the starch in the water containing the swollen starch may be a step of directly adding the starch, for example, or a step of dispersing the starch in water and then adding the same. May be

Generally, the high-viscosity polymer compound is more likely to be aggregated in water to form a lump as compared with a boron compound such as borax.
When lumps are generated, the lumps gradually dissolve, so the viscosity of the water-based adhesive may gradually increase, which may cause clogging of the liquid-feeding pipe of the water-based adhesive during corrugated board production, for example. May occur. Therefore, in the present invention, it is preferable to uniformly disperse the thickening polymer compound to increase the viscosity, from the viewpoint of stabilizing the viscosity of the aqueous adhesive.

The step of uniformly dispersing the thickening polymer compound is not particularly limited as long as it does not generate lumps of the thickening polymer compound in water. For example, a step of adding an aqueous solution of the thickening polymer compound. Alternatively, it may be a step of adding a mixed powder in which the thickening polymer compound and starch are mixed, and the thickening polymer compound is dispersed in a powder form by using a dispersion feeding means. It may be a step of charging, or two or more steps among them may be adopted.
Examples of the dispersion charging means include a flow jet mixer (manufactured by Koken Powtex Co., Ltd.) and the like.

The thickening polymer compound may be uniformly dispersed in water at any time when the water-based adhesive is produced. For example, initial addition water, that is, water charged before other materials are added. , Evenly dispersed in water containing swollen starch, or even dispersed in water containing unswollen starch, or both starches You may disperse | distribute in the water containing. For example, when using a thickening polymer compound having a property of being easily dissolved in water under alkaline conditions such as hydroxyethyl cellulose, when the thickening polymer compound is uniformly dispersed in water containing swollen starch, It is preferable from the viewpoint of stabilizing the viscosity of the water-based adhesive at an early stage.

As a specific example of the method for producing the water-based adhesive in the present invention, for example, starch and a swelling agent are added to water to produce a swelling liquid containing swollen starch, and the unswelled starch and the swelling liquid are added. A production method in which a viscous polymer compound is added may be mentioned. The starch and the high-viscosity polymer compound may be added all at once or may be added separately.

The corrugated board of the present invention is manufactured by using the water-based adhesive of the present invention, and the corrugated core is bonded to one or both sides of the core by the water-based adhesive. It has a liner, and is characterized in that the above-mentioned water-based adhesive of the present invention is used for bonding the core and the liner. Since the corrugated board of the present invention is manufactured using the above-described water-based adhesive of the present invention, it is possible to provide a corrugated board not containing a boron compound such as borax (corrugated board not containing borax) according to the present invention. Becomes Further, according to the present invention, when a very small amount of borax is used in the water-based adhesive of the present invention, it is possible to provide a corrugated board in which the amount of a boron compound such as borax is used is smaller than that of currently used corrugated board. It will be possible.

The water-based adhesive of the present invention can be suitably used for producing paper products such as paper containers in addition to corrugated board. The water-based adhesive of the present invention can also be used for bonding corrugated board products manufactured using corrugated board.

The corrugated board of the present invention can be manufactured by using a corrugator usually used in manufacturing corrugated board. That is, the corrugated board manufacturing method of the present invention uses a corrugator that has at least a glue roll and a means for attaching an aqueous adhesive to the glue roll, and brings the top edge of the corrugated core into contact with the glue roll. In the method for producing a corrugated board, which comprises a step of applying an aqueous adhesive to the top edge, and a step of attaching a liner to the surface side of the core, on which the aqueous adhesive is applied, the above-mentioned aqueous adhesive of the present invention is used. It is characterized by using.

In the corrugated board manufacturing method of the present invention, the water-based adhesive of the present invention is more likely to cause roughening of the adhesive surface on the adhesive roll surface, as compared with conventional aqueous adhesives containing a boron compound such as borax. As the glue roll, it is preferable to use a gravure roll having an uneven surface engraved, from the viewpoint of stabilizing the adhesive strength of the corrugated board to be produced.

[0035]

EXAMPLE An example of the present invention will be shown below to more specifically describe the present invention. In this example, a glue making device (made by Kakita Kogyo Co., Ltd.) was used as a device for producing an aqueous adhesive. All percentages in this example are weight%.

<Production of Water-based Adhesive 1> 360 L of water (3
7.0%) to 38 ° C. and add 33 kg of starch to it.
(3.4%) was added, the mixture was stirred for 3 minutes, 5 kg (0.5%) of sodium hydroxide was added, the mixture was stirred for 15 minutes, 380 L (39.0%) of water was added, and then 36 ° C.
And heated to obtain a swelling liquid containing starch swollen with sodium hydroxide.

192 kg (19.7) of starch were added to this swelling solution.
%) And after stirring for 3 minutes, carboxymethyl cellulose (CMC Daicel 1270, manufactured by Daicel Chemical Industries, DS is 0.9, 1% aqueous solution viscosity is 190 mPa.
s) 2.7 kg (0.3%) was added and the mixture was stirred for 60 minutes to obtain a paste for corrugated board (aqueous adhesive 1).

<Production of Water-based Adhesive 2> Water 360 L (3
7.0%) to 38 ° C. and add 33 kg of starch to it.
(3.4%) was added, the mixture was stirred for 3 minutes, 5 kg (0.5%) of sodium hydroxide was added, the mixture was stirred for 15 minutes, 380 L (39.1%) of water was added, and then 36 ° C.
And heated to obtain a swelling liquid containing starch swollen with sodium hydroxide.

192 kg (19.7) of starch was added to this swelling solution.
%) And after stirring for 3 minutes, carboxymethyl cellulose (CMC Daicel 1350, manufactured by Daicel Chemical Industries, DS is 1.3, 1% aqueous solution viscosity is 250 mPa ·
s) 2.4 kg (0.2%) was added and the mixture was stirred for 60 minutes to obtain a paste for corrugated board (aqueous adhesive 2).

<Production of Water-based Adhesive 3> Water 360 L (3
6.9%) to 38 ° C. and add 33 kg of starch to it.
(3.4%) was added, the mixture was stirred for 3 minutes, 5 kg (0.5%) of sodium hydroxide was added, the mixture was stirred for 15 minutes, 380 L (39.0%) of water was added, and then 36 ° C.
And heated to obtain a swelling liquid containing starch swollen with sodium hydroxide.

192 kg (19.7) of starch were added to this swelling solution.
%) And after stirring for 3 minutes, carboxymethyl cellulose (CMC Daicel 1130, manufactured by Daicel Chemical Industries, DS is 0.6, 1% aqueous solution viscosity is 70 mPa.
s) 4.1 kg (0.4%) was added and stirred for 60 minutes to obtain a paste for corrugated board (aqueous adhesive 3).

<Production of Water-based Adhesive 4> 360 L of water (3
7.0%) to 38 ° C. and add 33 kg of starch to it.
(3.4%) was added, the mixture was stirred for 3 minutes, 5 kg (0.5%) of sodium hydroxide was added, the mixture was stirred for 15 minutes, 380 L (39.1%) of water was added, and then 36 ° C.
And heated to obtain a swelling liquid containing starch swollen with sodium hydroxide.

192 kg (19.7) of starch was added to this swelling liquid.
%) And after stirring for 3 minutes, carboxymethyl cellulose (CMC Daicel 1130, manufactured by Daicel Chemical Industries, DS is 0.6, 1% aqueous solution viscosity is 70 mPa.
s) 0.5 kg (0.1%) and hydroxyethyl cellulose (HEC Daicel EP850, manufactured by Daicel Chemical Industries, Ltd., 1% aqueous solution viscosity is 2000 mPa.s) 0.9 k
g (0.1%) was added, and the mixture was stirred for 60 minutes to obtain a paste for corrugated board (aqueous adhesive 4).

<Production of Water-based Adhesive 5> 360 L of water (3
6.9%) to 38 ° C. and add 33 kg of starch to it.
(3.4%) was added, the mixture was stirred for 3 minutes, 5 kg (0.5%) of sodium hydroxide was added, the mixture was stirred for 15 minutes, 380 L (39.0%) of water was added, and then 36 ° C.
And heated to obtain a swelling liquid containing starch swollen with sodium hydroxide.

192 kg (19.7) of starch were added to this swelling liquid.
%) And after stirring for 3 minutes, carboxymethyl cellulose (CMC Daicel 1130, manufactured by Daicel Chemical Industries, DS is 0.6, 1% aqueous solution viscosity is 70 mPa.
s) 0.5 kg (0.1%) and guar gum (Somar GU / F, manufactured by Somar Company, 1% aqueous solution has a viscosity of 3000 m
Pa. s) 0.8 kg (0.1%) was added and the mixture was stirred for 60 minutes to obtain a bonding paste for cardboard (aqueous adhesive 5).

<Production of Water-based Adhesive 6> 360 L of water (3
6.9%) to 38 ° C. and add 33 kg of starch to it.
(3.4%) was added, the mixture was stirred for 3 minutes, 5 kg (0.5%) of sodium hydroxide was added, the mixture was stirred for 15 minutes, 380 L (39.0%) of water was added, and then 36 ° C.
And heated to obtain a swelling liquid containing starch swollen with sodium hydroxide.

192 kg (19.7) of starch was added to this swelling solution.
%) And after stirring for 3 minutes, sodium alginate (Kimitsu algin B-3, manufactured by Kimitsu Chemical Industry Co., Ltd., 1% aqueous solution viscosity is 350 mPa · s) 2.0 kg (0.2%)
And polyvinyl alcohol (PVA235, manufactured by Kuraray Co., saponification degree 88%, polymerization degree 3500, 2% aqueous solution viscosity 40 mPa.s) 3.0 kg (0.3%),
The mixture was stirred for 60 minutes to obtain a paste for cardboard (water-based adhesive 6).

<Production of Water-based Adhesive 7> 360 L of water (3
6.9%) to 38 ° C. and add 33 kg of starch to it.
(3.4%) was added, the mixture was stirred for 3 minutes, 5 kg (0.5%) of sodium hydroxide was added, the mixture was stirred for 15 minutes, 380 L (39.0%) of water was added, and then 36 ° C.
And heated to obtain a swelling liquid containing starch swollen with sodium hydroxide.

192 kg (19.7) of starch was added to the swelling liquid.
%), And after stirring for 3 minutes, 4.0 kg (0.4%) of sodium polyacrylate (Rheogic 830L, manufactured by Nippon Pure Chemical Co., Ltd., 1% aqueous solution viscosity is 80 mPa · s) is charged and stirred for 60 minutes. Then, a paste for corrugated board (water-based adhesive 7) was obtained.

<Production of Borax-Containing Aqueous Adhesive> On the other hand, a conventional paste for corrugated board containing borax was produced for comparison. Up to the swelling liquid, it is the same as the CMC-filled paste. Starch 192 kg (19.7%) was added to this swelling liquid, and the mixture was stirred for 3 minutes and then borax 3.2 kg (0.3%) was added.
The mixture was stirred for 5 minutes to obtain a paste for corrugated board (borax-containing water-based adhesive).

<Lamination> Using the above water-based adhesive, a front liner, a center core and a back liner were laminated to produce a corrugated board. For the production of corrugated board, a corrugator having a laminating apparatus shown in FIG. 1 was used to adhere the base papers according to the Stainhole method generally used in this field to produce corrugated board.

The production of corrugated cardboard using the above-mentioned laminating apparatus will be briefly described. The core raw paper is formed into a corrugated plate shape by a roll having a gear-shaped cross section and is conveyed. The adhesive glue is applied to the top edge of the sheet by means of a glue roll, and the core ridges of the core raw paper coated with the aqueous adhesive are sequentially brought into contact with the back liner, and the abutting portion is heated to bond the glue. Instantly solidify and paste the base paper,
A single-sided corrugated board was manufactured. Further, a double-sided corrugated board was manufactured by applying the water-based adhesive to the edge of the center corrugated crest on the side not coated with the core raw paper in the same manner, aligning the front liner and heating the same.

The laminating device has a glue roll. As shown in FIG. 1, the glue roll is arranged at a position where the water-based adhesive contained in the container is attached and at a position where the glue roll comes into contact with the top edge of the core. In this example, a corrugated board was manufactured using a gravure roll as the glue roll and using the water-based adhesives 1 to 7 as the bonding paste for corrugated board. Regarding the water-based adhesives 1, 2 and 5, corrugated board was manufactured using a plain roll as a glue roll. As the gravure roll, a roll having a mesh-shaped concavo-convex formed on the surface (the mesh is concave and the periphery thereof is convex) was used. Further, as the plain roll, a roll having a non-directional fine unevenness formed on the surface by uniformly roughening the surface was used.

<Evaluation> The above-mentioned water-based adhesives 1 to 7 and the above-mentioned borax-containing water-based adhesive were subjected to physical property tests of the manufactured water-based adhesives and various tests from manufacture of the water-based adhesives to pasting, and evaluated. did. The test items and test contents are shown below. Table 1 shows the results of the physical property test of the water-based adhesive and the bonding test of the water-based adhesive when the water-based adhesive 1 was used.
Table 2 shows the results of the above-mentioned physical property test and laminating test when each of the water-based adhesives 2 to 7 was used. The evaluation results of the above borax-containing water-based adhesives were all good (“◯”).

(1) Confirmation of Decrease in Viscosity About 60 hours after the production of the water-based adhesive, a certain amount of each of the water-based adhesives was put in a container called Zahn cup having a hole at the bottom, and the water-based adhesive was The time required for the agent to completely flow out from the container was measured. The Zahn cup is generally the simplest tester used for measuring the viscosity of inks and the like. In this example, "Zahn Cup No. 4" manufactured by Sogo Co., Ltd. was used.

(2) Sheet pasting state The pasting portion of the corrugated board obtained by the above pasting was visually observed and evaluated.

(3) Production of water-based adhesive In the production of the above-mentioned water-based adhesive, an operator monitored and evaluated a series of production processes.

(4) Paste viscosity A certain amount of the water-based adhesive was placed in a container called Zahn cup having a hole at the bottom, and the time until the water-based adhesive flowed out from the container was measured.

(5) Bonding status In the manufacture of the above corrugated board, the operator monitored and evaluated a series of bonding processes for bonding the base paper.

(6) Adhesive Roll Surface Condition The adhesive state of the water-based adhesive on the adhesive roll surface was visually observed and evaluated.

(7) Bonding Strength Test (Pin Test) Regarding the corrugated board obtained by the above bonding, a pin tester and a load cell type compression tester were used to carry out JIS Z test.
A test based on 0402 "Corrugated Cardboard Adhesion Test Method" was conducted and evaluated.

(8) Product pressure strength test Regarding the corrugated board obtained by the above-mentioned bonding, JIS Z is used by arbitrarily setting the dimensions using a corrugated board container compression tester.
The case pressure product strength of 0201 type according to 1507 “model of corrugated cardboard box” was measured and evaluated.

(9) Iodine reaction test Regarding the corrugated board obtained by the above-mentioned bonding, by immersing the bonded corrugated board in water, the front liner, the core and the back liner were peeled off, and iodine diluted with water was applied to these. By spraying, the starch of the water-based adhesive transferred to the cardboard base paper was reacted with iodine, and the uniformity of the water-based adhesive applied in the laminating process was evaluated by the result of the color reaction.

(10) Confirmation of sheet warp The laminated sheet was visually confirmed and evaluated.

[0065]

[Table 1]

[0066]

[Table 2]

From Tables 1 and 2, the water-based adhesives 1 to 7 are
It was found that it has almost the same performance as a borax-containing water-based adhesive conventionally used as a bonding paste for corrugated board. This has revealed that it is possible to manufacture corrugated board containing no borax.

[0068]

The water-based adhesive of the present invention comprises water, starch, and
Since it contains a water-soluble polymer compound that exhibits thickening in water and one or more thickening polymer compounds selected from synthetic resin emulsions, the amount of the boron compound used is further reduced, or the boron compound is used. It is possible to provide a water-based adhesive that does not use the above, to further reduce the amount of the boron compound used, or to provide a paper product such as corrugated board which does not contain the boron compound and does not contain the boron compound such as borax.

In the present invention, the thickening polymer compound is carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, carrageenan, guar gum, pectin, sodium alginate, carboxylated starch,
One or more selected from polyvinyl alcohol and sodium polyacrylate is even more effective in providing an aqueous adhesive excellent in environmental protection and stability.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a bonding apparatus (single facer) used in an example of the present invention.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09J 101/00 C09J 101/00 201/00 201/00 F term (reference) 3E078 BB02 CC12 CC23 CC26 CC38 CC42 4D075 AC25 CA13 CA47 DA03 DA06 DA31 DB18 DC36 EA06 EA35 EB07 4F100 AJ06B AJ06C AJ07B AJ07C AK01B AK01C AT00A BA02 BA03 BA06 BA07 BA10A BA10B BA10C EC18B EC18C GB16BA16BA16 BA16BA16BA16BA16BA02BA01BA02BA01

Claims (10)

[Claims] 1. A water-based adhesive containing water, starch, and a thickening polymer compound, wherein the thickening polymer compound is a water-soluble polymer compound and a synthetic resin that exhibit thickening properties in water. A water-based adhesive that is one or more selected from emulsions. 2. An aqueous adhesive containing water, starch, and a thickening polymer compound, wherein the starch contains 15 to 30% by weight in total of the total amount of the aqueous adhesive in terms of solid amount. And containing 5 to 25% by weight of starch swollen by a swelling agent with respect to the total amount of the starch, and the thickening polymer compound is one selected from water-soluble polymer compounds and synthetic resin emulsions that exhibit thickening properties in water. Or the water-based adhesive which is 2 or more types. 3. The water-based adhesive according to claim 1, wherein at least one kind of the thickening polymer compound is one kind or two or more kinds selected from a polysaccharide and a derivative thereof. 4. The water-based adhesive according to claim 1, wherein at least one kind of the thickening polymer compound is one kind or two or more kinds selected from a cellulose derivative. 5. At least one kind of the thickening polymer compound is carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, carrageenan,
The water-based adhesive according to claim 1 or 2, which is one or more selected from guar gum, pectin, sodium alginate, carboxylated starch, polyvinyl alcohol and sodium polyacrylate. 6. A method for producing the aqueous adhesive according to claim 1, wherein the step of swelling starch in water and the step of dispersing the starch in water containing the swollen starch. A thickening polymer compound is added to at least one of the step, initial addition water, water containing swollen starch, water containing unswollen starch, and water containing swollen starch and unswollen starch. A method for producing an aqueous adhesive, which comprises a step of uniformly dispersing. 7. The step of uniformly dispersing the thickening polymer compound comprises the steps of adding an aqueous solution of the thickening polymer compound, and adding a mixed powder of the thickening polymer compound and starch. 7. The method for producing an aqueous adhesive according to claim 6, wherein the method comprises at least one of a step of dispersing the thickening polymer compound in a powder form using a dispersion charging means and charging the powder into water. . 8. The method according to claim 1, further comprising a corrugated core and a liner bonded to one or both sides of the core with an aqueous adhesive, wherein the core and the liner are bonded together. From 5
A corrugated board using the water-based adhesive according to any one of 1. 9. A corrugator having at least a glue roll and a means for adhering an aqueous adhesive to the glue roll is used, and the top edge of a corrugated core is brought into contact with the glue roll to bring it to the top edge. The process of applying a water-based adhesive and the core
A method of manufacturing a corrugated board comprising a step of attaching a liner to a surface coated with the water-based adhesive, wherein the water-based adhesive according to any one of claims 1 to 5 is used for the water-based adhesive. Characteristic cardboard manufacturing method. 10. The method of manufacturing a corrugated board according to claim 9, wherein the glue roll is a gravure roll whose surface is engraved with unevenness.