JPH1088090A - Waterresistant adhesive composition for corrugated card board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive compsn. which exhibits a good workability and a high water resistance without emitting a formalin odor in bonding base paper of a corrugated cardboard by incorporating starch and an ethylene-α,β- ethylenically unsatd. carboxylic acid copolymer resin into the same. SOLUTION: Water resistance is improved by a strong bonding formed by the reaction of carboxyl groups of the copolymer resin in the cement liq. with starch. Further addition of a water-soluble high-molecular compd. to the cement liq. thickens the compsn. and can give it a viscosity suitable for the use on a corrugator. Esp. a water-soluble polymer compd. having amido or epoxy groups (e.g. a cationic water-soluble polyamide resin) strengthens the bonding between starch and base paper. Since a water-base resin emulsion is excellent in wetting the surface of base paper and in permeating fibers, its joint use with above ingredients can improve a normal-state adhesive performance. The compounding ratio of starch: the copolymer resin emulsion: the water-soluble high molecular compd.: the water-base resin emulsion is 100:(10-400):(1-30):(10-400).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a starch, ethylene-
The present invention relates to a water-resistant adhesive composition for corrugated board mainly comprising an α, β ethylenically unsaturated carboxylic acid copolymer resin emulsion.

[0002]

2. Description of the Related Art Corrugated cardboard adhesives in Japan are mainly made of starch from the viewpoint of economy and workability. However, this starch-based adhesive has poor water resistance and is wet. It has the disadvantage that it swells and softens when wet and loses its adhesive strength. Conventionally, a method of adding a formalin-based thermosetting resin, such as a urea resin, a melamine resin, a phenol resin, a resorcinol resin, or a ketone resin, to a starch in order to impart water resistance to a starch-based cardboard adhesive. Have been done. As inventions relating to a method of adding these thermosetting resins, those relating to urea resins include, for example, JP-A-56-41278.
JP-A-51-117731 and JP-A-51-12 are related to melamine, phenol and resorcinol resins.
JP-A-56-34775 and the like are related to ketone resins such as No. 4132.

However, the method of adding these water-soluble resins to a starch-based adhesive, although slightly improving the water resistance, is not practically sufficient, and requires a high temperature and a long time for curing. The workability is poor, and there remains a fatal problem of generating formalin. On the other hand, as a synthetic adhesive, there is a normal adhesive having excellent water resistance, such as vinyl acetate resin, ethylene vinyl acetate resin, and acrylic resin adhesive, but is applied by a corrugator that requires quick setting properties. In this case, it cannot be adapted sufficiently, and there are many problems in terms of workability such as gum up to a roll.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an adhesive for corrugated cardboard which improves the above points at the time of laminating corrugated cardboard, has no formalin odor, has good workability, and has excellent water resistance. That is.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and have found that an adhesive containing starch, an ethylene-α, β-ethylenically unsaturated carboxylic acid copolymer resin emulsion. The composition, furthermore, a water-soluble polymer compound, an adhesive composition containing one or both of the aqueous resin emulsion, it is possible to significantly improve the water resistance of the cardboard while maintaining good workability. Heading, the present invention has been completed. That is, the present invention is a water-resistant adhesive composition for corrugated board, comprising starch and an ethylene-α, β-ethylenically unsaturated carboxylic acid copolymer resin emulsion.

Regarding the mechanism of the improvement of water resistance by the adhesive composition of the present invention, the carboxyl group of the ethylene-α, β-ethylenically unsaturated carboxylic acid copolymer resin in the size liquid reacts with starch at the time of adhesion, It is presumed that the water resistance of the starch adhesive layer is improved by forming a strong bond.
Further, the present invention provides a water-resistant adhesive composition for corrugated cardboard, which further comprises one or both of a starch and an ethylene-α, β-ethylenically unsaturated carboxylic acid copolymer resin emulsion, a water-soluble polymer compound and an aqueous resin emulsion. Things.

The water-soluble polymer compound is starch, ethylene-
When added to a size liquid composed of an α, β ethylenically unsaturated carboxylic acid copolymer resin emulsion, a viscosity suitable for use of a corrugator can be imparted by the thickening action of the polymer. Further, among the water-soluble polymer compounds, those having an amide group or an epoxy group in the molecule, such as a cationic water-soluble polyamide resin, reinforce the bond between starch and base paper when added to the size liquid. effective.

[0008] The aqueous resin emulsion, especially for corrugated cardboard base paper that has been subjected to a reinforced water-resistant treatment, has good wettability to the surface and good permeability between fibers. The normal state adhesion performance can be significantly improved without lowering the adhesion performance. Although the ratio of each component in the present invention is not particularly limited, the following ranges are desirable in practical use. That is, starch:
Ethylene-α, β ethylenically unsaturated carboxylic acid copolymer resin emulsion: water-soluble polymer compound: aqueous resin emulsion = 100: 10 to 400: 1 to 30:10 to 40
0.

When the proportion of the ethylene-α, β ethylenically unsaturated carboxylic acid copolymer resin emulsion in the present adhesive is more than 400 parts by weight per 100 parts by weight of starch,
If the initial adhesive strength suitable for the corrugator adhesion cannot be obtained, if it is less than 10 parts by weight, sufficient water resistance cannot be obtained. When the amount of the water-soluble polymer is less than 1 part by weight based on 100 parts by weight of starch, depending on the type of starch, sizing on a roll may be deteriorated, and the starch in the paste solution may settle. Lamination with a corrugator cannot be performed. On the other hand, when it is larger than 30 parts, it is not preferable because scattering of the size liquid and control of the size of the glue become difficult, resulting in inconvenient work. With respect to the aqueous resin emulsion, when the amount is more than 400 parts by weight, the initial adhesive strength suitable for lamination with a corrugator cannot be obtained, and when the amount is less than 10 parts by weight, a remarkable effect of improving the normal adhesion performance is exhibited. It becomes difficult.

The starch used in the present invention includes corn starch (dent, waxy, high amylose), tapioca starch, potato starch, sweet potato starch, wheat starch, sago starch and various derivatives of these starches, for example, etherified starch. There are starches, esterified starches, acid-treated starches, oxidized starches, etc., which have been treated by existing processing methods.
The production of the ethylene-α, β ethylenically unsaturated carboxylic acid copolymer resin emulsion in the present invention was based on the method described in JP-A-4-153239.

That is, ethylene and an α, β ethylenically unsaturated carboxylic acid (monocarboxylic acids include, for example, unsaturated carboxylic acids having usually 6 or less carbon atoms such as acrylic acid, methacrylic acid, crotonic acid and isocrotonic acid). To
Examples of the dicarboxylic acid include, for example, a random copolymer of maleic acid, fumaric acid, and itaconic acid) or a copolymer in which α, β ethylenically unsaturated carboxylic acid is grafted on polyethylene, and Is a method of emulsifying using a surfactant, emulsifying by mechanical dispersion, or emulsifying and dispersing by a basic substance using a terpolymer to which a third component is added as a raw material. Manufactured by.

As the basic substance, alkali metals such as sodium hydroxide, lithium hydroxide and potassium hydroxide, and amines such as ammonia and triethylamine are generally used. The water-soluble polymer compound in the present invention includes carboxymethyl cellulose, methyl cellulose, gum arabic, other thickening polysaccharides, polyvinyl alcohol, isobutylene-maleic acid copolymer, sodium polyacrylate, polyacrylamide, (cation, anion, Amphoteric) and cationic water-soluble polyamide resins.

These water-soluble polymer compounds can be used alone or in combination of two or more. this house,
In order to obtain a cationized polyacrylamide, there are a method of polymerizing a cationized monomer and a method of cationizing a polymerized acrylamide. The former method is generally used. In addition, among the water-soluble polymer compounds, as a method for producing a cationic water-soluble polyamide resin, for example, a polyamide urea obtained by dehydration condensation of a polyalkylene polyamine and a dibasic carboxylic acid or a derivative thereof,
There is a method of cationizing by adding epihalohydrin.

Examples of the polyalkylene polyamine include polyethylene polyamine, polypropylene polyamine, polybutylene polyamine, polyisobutylene polyamine, etc. Among them, polyethylene polyamine is preferable, and diethylene triamine, triethylene tetramine or tetraethylene pentamine is most preferable. .

Typical examples of the polyalkylene polyurea include a deammonification reaction product from the above-described polyalkylene polyamine and urea. These polyalkylene polyamines or polyalkylene polyureas may be used alone or in combination of two or more, and may be used in combination with each other. Also,
An aliphatic diamine such as ethylenediamine, propylenediamine or hexamethylenediamine is contained in an amount of 50 mol% or less of these polyalkylene polyamines and / or
Alternatively, it may be used in combination with a polyalkylene polyurea.

The dibasic carboxylic acid or a derivative thereof includes a compound having two carboxyl groups in a molecule, an ester thereof, and an acid anhydride thereof. Specifically, succinic acid, maleic acid, glutaric acid, adipic acid, sebacic acid, aliphatic dibasic carboxylic acids such as fumaric acid and esters thereof, and further,
There are acid anhydrides such as succinic anhydride, maleic anhydride and fumaric anhydride, and these may be used alone or in combination of two or more. As epihalohydrin, epichlorohydrin or epibromohydrin is used.

The aqueous resin emulsion used in the present invention includes a vinyl acetate resin emulsion, an ethylene / vinyl acetate copolymer resin emulsion, a (meth) acrylic acid resin emulsion, an acrylic / styrene polymer resin emulsion, and a styrene / butadiene / methacrylic acid emulsion. Polymerized resin emulsion, styrene / butadiene latex (SBR), chloroprene latex (CR), acrylonitrile / butadiene latex (NBR), polyacrylester latex, polyvinylidene chloride latex, etc. Two or more can be used in combination.

Among these, emulsions that do not use polyvinyl alcohol as a protective colloid do not gel even when a normal paste containing borax is mixed in a paste making operation in a cardboard factory. Therefore, when switching the glue, a washing step before the glue is not required, which is more preferable in terms of productivity. Since the adhesive composition according to the present invention contains no formalin-based resin at all, no formalin is generated from corrugated cardboard after production, and it is much more sanitary than conventional adhesives.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The production examples and examples of the present invention are shown below, but the present invention is not limited to these examples. (Production Example 1) Preparation of Ethylene-α, β Ethylenically Unsaturated Carboxylic Acid Copolymer Emulsion (Emulsion) Primacol 5990 (manufactured by Dow Chemical Company, ethylene-unsaturated carboxylic acid copolymer resin) ) To 1
00 g, 9 g of 28% aqueous ammonia and 290 g of water were added, and the mixture was emulsified at 150 ° C. for 30 minutes. The obtained aqueous dispersion had a nonvolatile content of 25.2% and a pH of 8.6.

(Production Example 2) Preparation of Ethylene-α, β Ethylenically Unsaturated Carboxylic Acid Copolymer Resin Emulsion (Emulsion) Primacol 5990 (manufactured by Dow Chemical Company, ethylene-unsaturated carboxylic acid) Copolymer resin)
00 g, 9 g of 0.1% NaOH aqueous solution, and 290 g of water
In addition, the mixture was emulsified at 150 ° C. for 30 minutes. The obtained aqueous dispersion had a nonvolatile content of 25.9% and a pH of 9.0.

(Production Example 3) Preparation of cationic water-soluble polyamide resin 113.4 g of diethylenetriamine was placed in a 500 ml four-necked flask equipped with a thermometer, a reflux condenser, and a stirring rod.
(1.1 mol), water 50 g, adipic acid 146.1 g
(1.0 mol), and the temperature was raised while draining water.
The reaction was performed at 0 to 185 ° C for 5 hours. After cooling to 60 ° C,
Water was added to obtain a 50% polyamide aqueous solution. 42.6 g (1 mol) of this polyamide aqueous solution and 110 g of water were charged into another flask, and 13.9 g of epichlorohydrin was added thereto.
(0.15 mol) was added dropwise at 50 ° C. over 30 minutes, then reacted at 60 ° C. for 2 hours, cooled to room temperature, and p-hydrochloric acid was added.
After adjusting H to 4.0, a cationic water-soluble polyamide resin having a solid content of 50% was obtained.

[0022]

【Example】

(Example 1) Regular corn starch [produced by Honen Corporation] 32 in 424.4 g of water at 40 ° C 32
0.5 g was suspended, 300 g of the emulsion was gradually added thereto, and stirring was continued for 10 minutes to obtain a paste liquid. (Example 2) Regular corn starch [manufactured by Honen Corporation] 32 in 424.4 g of water at 40 ° C 32
0.5 g was suspended, 300 g of the emulsion was gradually added thereto, and stirring was continued for 10 minutes to obtain a paste liquid.

Example 3 324.6 g of regular corn starch (produced by Honen Corporation) was suspended in 347.7 g of water at 40 ° C., and 300 g of an emulsion was gradually added thereto. 42 g of an aqueous solution of Metroose 65SH-4000 [manufactured by Shin-Etsu Chemical Co., Ltd.] was added, and after the addition, stirring was continued for 10 minutes to obtain a paste size solution.

Example 4 160.9 g of phosphoric acid-crosslinked tapioca starch (produced by Honen Corporation) was suspended in 129.4 g of water at 40 ° C., and 300 g of an emulsion was gradually added thereto. .5% Metros 6
5SH-4000 [manufactured by Shin-Etsu Chemical Co., Ltd.]
2.8 g was added, and after the addition, stirring was continued for 10 minutes to obtain a paste liquid.

Example 5 324.6 g of regular corn starch (produced by Honen Corporation) was suspended in 347.7 g of water at 40 ° C., and 297 g of an emulsion was gradually added thereto, and 0.5% of the emulsion was added. Carboxymethylcellulose [Daiichi Kogyo Seiyaku Co., Ltd.] aqueous solution
After adding 2 g and further adding 3 g of cationic water-soluble polyamide resin, stirring was continued for 10 minutes to obtain a paste liquid.

(Example 6) 333.3 g of regular corn starch (produced by HONEN CORPORATION) was suspended in 401.1 g of water at 40 ° C, and 300 g of an emulsion was gradually added thereto. 45 g of a cationized polyacrylamide aqueous solution was added, and stirring was continued for 10 minutes to obtain a paste liquid.

(Example 7) 333.4 g of regular corn starch (produced by HONEN CORPORATION) was suspended in 401.6 g of water at 40 ° C, and 300 g of an emulsion was gradually added thereto. After adding 45 g of a cationized polyacrylamide aqueous solution and further adding 0.3 g of a cationic polyamide resin, stirring was continued for 10 minutes to obtain a paste liquid.

(Example 8) Acid-treated potato starch [manufactured by Honen Corporation] in 347.7 g of water at 40 ° C.
324.6 g were suspended, and emulsion 300 was added thereto.
g, gradually adding 30% gum arabic KC
[Made by Minamikawa Kasei Co., Ltd.] 42 g of an aqueous solution was added, and after the addition,
Stirring was continued for 10 minutes to obtain a size liquid.

(Example 9) 160.9 g of regular course starch (produced by Honen Corporation) was suspended in 129.4 g of water at 40 ° C, and 300 g of an emulsion was gradually added thereto. 12.8 g of an aqueous solution of% Metroze 65SH-4000 (manufactured by Shin-Etsu Chemical Co., Ltd.) was added, and after the addition, stirring was continued for 10 minutes to obtain a finished paste solution.

Example 10 324.6 g of regular corn starch (produced by Honen Corporation) was suspended in 347.7 g of water at 40 ° C., and 297 g of an emulsion was gradually added thereto. After adding 42 g of an aqueous solution of Metroose 65SH (manufactured by Shin-Etsu Chemical Co., Ltd.) and further adding 3 g of a cationic polyamide resin, stirring was continued for 10 minutes to obtain a paste liquid.

(Example 11) 333.3 g of regular corn starch [produced by HONEN CORPORATION] was suspended in 401.1 g of water at 40 ° C, and 300 g of an emulsion was gradually added thereto. 45 g of a cationized polyacrylamide aqueous solution was added, and stirring was continued for 10 minutes to obtain a paste liquid.

Example 12 333.4 g of regular corn starch [produced by Honen Corporation] was suspended in 401.6 g of water at 40 ° C., and 300 g of an emulsion was gradually added thereto. 45 g of a cationized polyacrylamide aqueous solution was added, and
After adding 0.3 g of the cationic polyamide resin, stirring was continued for 10 minutes to obtain a paste liquid.

(Comparative Example 1) Stein-hole type adhesive for water-resistant corrugated cardboard Carrier starch for water-resistant corrugated cardboard adhesive in 550 g of hot water at 60 ° C [HR-1 manufactured by Honen Corporation.
60] was suspended in 120 g, and 13.8 sodium hydroxide was added thereto.
g was added for gelatinization, and stirring was continued at this temperature for 15 minutes to obtain a carrier part size liquid. On the other hand, 3
In a solution prepared by dissolving 9 g of borax in 1080 g of water at 5 ° C., 500 g of water-resistant cardboard adhesive main starch [HR-202, manufactured by Honen Corporation] and 500 g of formalin-based waterproofing agent [HR, manufactured by Honen Corporation,
-930] was added, and the mixture was thoroughly stirred and mixed to prepare a main part. The size liquid of the above-mentioned carrier part was gradually added to the main part, and after the addition, stirring was continued for 15 minutes to obtain a size liquid.

Comparative Example 2 Only the emulsion prepared based on Production Example 1 was used. (Comparative Example 3) Only emulsion prepared based on Production Example 2. Tables 1 and 2 show the results of evaluation (viscosity, adhesive strength, presence / absence of off-flavor) for the above Examples and Comparative Examples.

Adhesion Performance Test Method (Lamination) Using the paste liquid prepared in each of Comparative Example and Paste Making Examples 1 to 5, the temperature was maintained at 40 ° C., the paste liquid was circulated by a gear pump, and a liner [Honshu Paper Co., Ltd. ), Water-resistant liner, SK
-220) and a core [manufactured by Daishowa Paper Co., Ltd., water resistant core, S
CPT-180] is uniformly coated with a paste liquid amount of 0.12 g to 0.16 g on one 8.5 cm × 5 cm plate, and an 8.5 cm × 5 cm liner [Honshu Paper Co., Ltd., waterproof liner, SK-220] and thermocompression-bonded at 160 ° C. for 5 seconds.

Evaluation method (Adhesive force) The obtained test piece was subjected to normal adhesive strength and water resistant adhesive strength after 24 hours (adhesive strength after immersion in water at 20 ° C. for 60 minutes).
Was measured with a pin tester according to JIS-Z-0402. The initial adhesive strength was evaluated by performing a tensile test using a rheometer (manufactured by Leotech Co., Ltd.) equipped with a pin-shaped attachment immediately after lamination. (Viscosity) A case having the same viscosity (viscosity) as the current size liquid was determined as “suitable”, and the others were determined as “unsuitable”.

[0037]

[Table 1]

[0038]

[Table 2]

Example 13 140.4 g of an emulsion was gradually added to 285.6 g of water at 40 ° C., and 280.8 g of an acrylic-styrene copolymer resin emulsion [Movinyl DM60, manufactured by Hoechst Gosei Co., Ltd.] was added. , And gradually add 360.0 g of regular corn starch [manufactured by Honen Corporation], and further add 2.5% Metroze 65SH- for viscosity adjustment.
4000 [manufactured by Shin-Etsu Chemical Co., Ltd.] aqueous solution of 11.7
g was added, and after the addition, stirring was continued for 10 minutes to obtain a paste liquid.

Example 14 144.5 g of an emulsion was gradually added to 272.8 g of water at 40 ° C., and styrene-butadiene-methacrylic acid copolymer latex [KS207, manufactured by Sumitomo Chemical Co., Ltd.] 289 was added. 0.0g
, And gradually add 360.1 g of regular corn starch [manufactured by Honen Corporation], and further add 2.5% Metroze 65SH for viscosity adjustment.
-4000 [manufactured by Shin-Etsu Chemical Co., Ltd.] aqueous solution.
0 g was added, and after the addition, stirring was continued for 10 minutes to obtain a paste liquid.

Example 15 166.7 g of an emulsion was gradually added to 206.1 g of water at 40 ° C., and an ethylene-vinyl acetate copolymer resin emulsion [Movinyl 081, manufactured by Hoechst Synthesis Co., Ltd.] 333. 5 g was added, and 360.1 g of regular corn starch (manufactured by Honen Corporation) was gradually added thereto, and 2.5% Metroze 65SH- for viscosity adjustment was further added.
4000 [manufactured by Shin-Etsu Chemical Co., Ltd.]
g was added, and after the addition, stirring was continued for 10 minutes to obtain a paste liquid.

Example 16 157.8 g of an emulsion was gradually added to 232.9 g of water at 40 ° C., and 315.6 g of an acrylic resin emulsion [Movinyl 747, manufactured by Hoechst Gosei Co., Ltd.] was added. 360.1 g of regular corn starch [manufactured by Honen Corporation] is gradually added thereto, and 12.0 g of 2.5% Metroze 65SH-4000 [manufactured by Shin-Etsu Chemical Co., Ltd.] aqueous solution for adjusting viscosity is further added. Add, after addition, 1
Stirring was continued for 0 minutes to obtain a size liquid. Example 1
Evaluation of 3 to 16 (viscosity, adhesive strength, presence or absence of off-flavor)
Table 3 shows the results obtained.

[0043]

[Table 3]

[0044]

The adhesive composition for cardboard according to the present invention has no formalin odor, maintains very good workability, and significantly improves the water resistance of cardboard.

Claims (4)

[Claims] 1. A water-resistant adhesive composition for cardboard, comprising starch and an ethylene-α, β-ethylenically unsaturated carboxylic acid copolymer resin emulsion. 2. A water-resistant adhesive composition for cardboard, comprising starch, an ethylene-α, β-ethylenically unsaturated carboxylic acid copolymer resin emulsion, and a water-soluble polymer compound. 3. A water-resistant adhesive composition for cardboard, comprising starch, an ethylene-α, β-ethylenically unsaturated carboxylic acid copolymer resin emulsion and an aqueous resin emulsion. 4. A water-resistant adhesive composition for corrugated cardboard, comprising starch, an ethylene-α, β-ethylenically unsaturated carboxylic acid copolymer resin emulsion, a water-soluble polymer compound, and an aqueous resin emulsion.