JP3223378B2 - Water resistant adhesive composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starch-based water-resistant cardboard adhesive composition comprising a starch and a specific amount of a one-part water-resistant agent (cationic water-soluble resin).

[0002]

2. Description of the Related Art Most of cardboard adhesives in Japan are mainly made of starch from the viewpoints of economy and workability. However, starch-based adhesives have poor water resistance and may be wet or wet. When swelling and softening, the adhesive strength is lost.

Conventionally, as a method for making a starch-based cardboard adhesive water resistant, 1) a non-cationic formalin-based thermosetting resin such as urea resin, melamine resin, resorcinol resin, and ketone resin is added to starch. And 2) addition of an epoxy resin, or 3) addition of the thermosetting resin and the epoxy resin to starch in combination (Japanese Patent Laid-Open No. 50281/1991).

[0004]

However, the method (1) does not have sufficient water resistance, and the method (2) greatly increases the viscosity of the size liquid and is not suitable for continuous on-site use. In the method, the composition is troublesome because of the two-pack type, and the water-based thermosetting
Poor compatibility between the resin and hydrophobic epoxy resin,
As a result, there has been a defect that the expression of adhesive strength is slow, the bonding speed is reduced, and the productivity is reduced.

[0005] An object of the present invention is to improve the above-mentioned drawbacks in laminating water-resistant corrugated cardboard and to maintain high-speed laminating property.
Another object of the present invention is to provide an adhesive composition having excellent water resistance.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned object, and as a result, by adding a one-part cationic water-soluble resin to a starch-based adhesive, It has been found that the viscosity of the paste liquid is suppressed, and the water resistance of the cardboard can be significantly improved while maintaining the pasting speed at the conventional level.

[0007] The mechanism of the performance improvement by adding a resin to a starch-based adhesive is not clear, but is presumed as follows. That is, acetone resin can be diluted infinitely in water.
And permeate evenly between the starch granules in the adhesive composition
And coat the starch granules to promote fixation on the cardboard base paper,
With an initial adhesive force that can follow high-speed lamination during cardboard manufacturing
It seems to give. On the other hand, cationized polyamide
Amido group is a methylol group of acetone resin
By cross-linking with acetone resin of low molecular weight acetone resin
At the same time as reinforcing water resistance,
Use of crosslinked lamide resin-acetone resin on cardboard base paper
It is thought to promote the establishment.

[0008] As a result, the productized cardboard becomes rainy,
It can maintain its adhesive strength even when wet due to weather such as snow, exposed to water from the package contents, or exposed to high humidity, and therefore can be used for fish, vegetables and fruits. It can be applied to applications requiring high water resistance, such as cardboard boxes.

As described above, in order to express high-speed laminating property and high water resistance, the cationized resin is cationized with the ketone resin as described above .
It is essential to use a polyamide resin in combination, but at the same time, when performing a glue-making operation at a cardboard production plant, the water-proofing agent is a one-pack type water-proofing agent because the work is complicated in a two-pack type. Become indispensable.

The one-pack type water-proofing agent according to the present invention comprises a mixture of a ketone resin and a cationized polyamide resin, each of which is a water-soluble resin which can be infinitely diluted in water, and wherein the polyamide resin is a cationic resin. Has been
Even if coexisted with a ketone resin, it is stable for a long time and one-pack is possible, and in addition to high-speed laminating property and high water resistance, all the requirements for a water-resistant agent such as improved workability at the corrugated board production site It can be satisfied.

That is, the present invention is a water-resistant adhesive composition comprising 0.1 to 15 parts by weight of a one-part water-resistant agent comprising a ketone resin and a cationized polyamide resin with respect to 100 parts by weight of starch.

The ketone resin used in the present invention may be an ordinary non-cationic ketone resin, but it is preferable to use a cationized ketone resin.
As a method for producing the cationized ketone resin, 1.5 to 10 moles, preferably 2.0 to 6.0 moles, and 0.01 to 0.
A method in which 5 mol, preferably 0.05 to 0.2 mol, is condensed in an alkaline aqueous solution may be used. Formaldehyde is 1.5
If the amount is less than 10 mol, heat generation occurs rapidly and it is difficult to suppress the reaction. If the amount is 10 mol or more, the reaction rate is extremely slow, which is not practical. If the nitrogen-containing compound is less than 0.01 mol, cationization becomes insufficient, and if it is more than 0.5 mol, the water resistance does not increase so much, the cost increases, and industrial use becomes difficult. After the reaction, urea, melamine or the like may be mixed with the condensation product.

As the nitrogen-containing compound, guanidine hydrochloride,
Guanidine nitrate, guanidine phosphate, guanidine carbonate,
Guanidine sulfamate, aminoguanidine hydrochloride, aminoguanidine bicarbonate, guanidine salts such as aminoguanidine sulfate, amines such as triethylenetetramine, tetraethylenepentamine, dimethylamine, triethanolamine, guanylurea phosphate, guanylurea sulfate, Guanyl urea salts such as guanyl urea nitrate can be mentioned, and these can be used alone or in combination of two or more.

As a method for producing the cationized polyamide resin, a polyamide polyamine obtained by dehydration condensation of a polyalkylene polyamine and a dibasic carboxylic acid or a derivative thereof, or a polyalkylene polyurea and a dibasic carboxylic acid or a derivative thereof are used. A method may be used in which epihalohydrin is added to the dehydrated and condensed polyamide urea to cationize it. Formaldehyde may be co-condensed during the synthesis of the polyamide resin.

As the polyalkylene polyamine, there are polyethylene polyamine, polypropylene polyamine, polybutylene polyamine and the like. Among them, polyethylene polyamine is preferable, and among them, diethylene triamine, triethylene tetramine or tetraethylene pentamine is most preferable. A typical example of the polyalkylene polyurea is a deammonification reaction product of the above-described polyalkylene polyamine and urea.

These polyalkylene polyamines or polyalkylene polyureas may be used alone or in combination of two or more, or may be used in combination with each other. An aliphatic diamine such as ethylenediamine, propylenediamine or hexamethylenediamine may be used in combination with the polyalkylene polyamine and / or polyalkylene polyurea in a range of 50 mol% or less.

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, aliphatic dibasic carboxylic acids such as succinic acid, glutaric acid, adipic acid, sebacic acid, maleic acid, and fumaric acid and their esters, or aromatic acids such as phthalic acid, isophthalic acid, and terephthalic acid There are dibasic carboxylic acids and their esters, and acid anhydrides such as succinic anhydride, maleic anhydride and fumaric anhydride. These may be used alone or in combination of two or more.

As epihalohydrin, epichlorohydrin or epibromohydrin is used.

In the present invention, the mixing ratio of the ketone resin and the cationized polyamide resin falls within the range of ketone resin / cationized polyamide resin = 1/99 to 99/1. In the present invention, the compounding amount of the one-pack type water-proofing agent with respect to starch can be compounded in any ratio within a range where water resistance can be obtained without any particular limitation.However, due to a balance between the compounding effect and economy, Solid content for 100 parts by weight of starch
0.1% 50% one-component water-resistant agent (cationic water-soluble resin)
It is desirable that the compounding amount be 15 to 15 parts by weight, preferably 1 to 10 parts by weight. That is, the effect of imparting water resistance is weak at 0.1 parts by weight or less, and even at 15 parts by weight or more, no remarkable improvement in water resistance is seen, conversely, the cost rises, the disadvantage of increasing the viscosity of the size liquid appears, However, it is not realistic.

The one-pack type water-proofing agent of the present invention exhibits effects such as improvement of water resistance and initial adhesive strength by being added to not only an adhesive consisting of starch alone but also an adhesive containing starch as a main component. Therefore, the water-resistant adhesive composition of the present invention is also effective as a starch-based adhesive for wallpaper, interleaf paper, etc. in addition to corrugated cardboard applications.

[0021]

Embodiments of the present invention will be described below, but the gist of the invention is not limited thereto.

Example (1) 113.4 g (1.1 mol) of diethylenetriamine, 50 g of water and 146.1 g (1.0 mol) of adipic acid were charged into a 500 mL four-necked flask equipped with a thermometer, a reflux condenser, and a stirring rod. The temperature was raised while pulling, and the reaction was carried out at 180 to 185 ° C for 5 hours. After cooling to 60 ° C., water was added to obtain a 50% polyamide aqueous solution. 42.6 g (0.1 mol) of this polyamide aqueous solution and 110 g of water were charged into another flask, and 13.9 g (0.15 mol) of epichlorohydrin was added dropwise at 50 ° C. over 30 minutes, and then reacted at 60 ° C. for 2 hours. Then, the pH was adjusted to 4.0 with hydrochloric acid to obtain a cationic water-soluble polyamide resin.

In a 500 mL four-necked flask similar to the above, 40%
Formalin (225 g, 3.0 mol), acetone (58 g, 1.0 mol) and 25% caustic soda (5 mL) were charged and reacted at 50 ° C. for 3 hours. Then 9.5 g of tetraethylenepentamine (0.05
Mol) and the reaction was further continued for 1 hour, cooled to room temperature, and adjusted to pH 7.5 with 20% formic acid to obtain a cationic water-soluble acetone resin. Equivalent amounts of the cationized acetone resin and the cationized polyamide resin thus obtained were mixed to prepare a solid content of 50%, thereby obtaining a waterproofing agent A.

(2) The following commercially available waterproofing agents were used for comparing the performance of the waterproofing agent according to the present invention. Ketone resin: Dick Hercules Co., Ltd. Epinox P-468L (adjusted solid content to 50%) with water-proofing agent B
And Water-soluble epoxy compound: SR- manufactured by Sakamoto Pharmaceutical Co., Ltd.
8EG was adjusted to have a solid content of 50% to obtain a waterproofing agent C. Ketone resin: EPICNOX P-468L manufactured by Dick Hercules Co., Ltd. and water-soluble epoxy resin (non-cationic): TK-3000 manufactured by HONEN CORPORATION are mixed in equal amounts, and the solid content is adjusted to 50% to make it water resistant. Agent D.

(3) 120 kg of Carrier starch [HR-160, manufactured by Honen Corporation] is suspended in 550 L (liter) of hot water at 60 ° C., and 13.8 kg of caustic soda is added thereto. The mixture was gelatinized and further stirred at this temperature for 15 minutes to obtain a carrier size liquid. On the other hand, 500 kg of a water-resistant cardboard adhesive main starch [HR-202, manufactured by Honen Corporation] was previously dissolved in a solution of 9 kg of borax in 1080 L of water at 35 ° C. and 31 kg of the above-mentioned water-resistant agent (test number 5 was 0.31 kg, Test number 6
124Kg) was added and mixed well with stirring to prepare a main part. The above-mentioned carrier size liquid was gradually added to the main portion, and after the addition, stirring was continued for 15 minutes to obtain a finished size liquid.

In order to clarify the effect of the present invention,
Using a water-resistant corrugated cardboard adhesive solution prepared by blending a cationic water-soluble resin synthesized by the above-described method and a commercially available water-resistant resin as a control, a corrugator manufactured by Mitsubishi Langston Co., Ltd. : 200m / min, bonding width: 220
0mm), the liner (Daisyo Showa Paper, water-resistant liner, KT-280) and the core (Daishowa Paper, water-resistant core,
(SCPT-180) was pasted, and the pasting speed was observed. The obtained corrugated cardboard sheet was cut into a size of 8 cm × 5 cm to obtain a test piece, and the adhesive strength in a normal state and the adhesive strength in a wet state of each test piece after immersion in water at 20 ° C. for 3 minutes and 60 minutes were measured. It was measured with a pin tester according to JIS-Z-0402. Further, the viscosity was measured by the Ford cup method immediately after the above-mentioned adhesive paste liquid was formed and after standing at 40 ° C. for 24 hours. The results are shown in the table below.

[0027]

[0028]

As is apparent from the above results, the use of the water-resistant adhesive composition using the one-pack type water-proofing agent of the present invention makes the operation simple and does not reduce the bonding speed. A corrugated product having excellent water resistance can be obtained.

Although the one-pack type water-proofing agent of the present invention has been mainly described as an adhesive composition for corrugated cardboard because it is most suitable for making the starch-based adhesive composition water-resistant, it is not limited to the adhesive. It can be used as a waterproofing agent for the composition.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C09J 1/00-201/10 C08L 1/00-101/16

Claims (3)

(57) [Claims] 1. A water-resistant adhesive composition comprising 0.1 to 15 parts by weight of a one-part water-resistant agent comprising a ketone resin and a cationized polyamide resin with respect to 100 parts by weight of starch. 2. The water-resistant adhesive composition according to claim 1, which is an adhesive for cardboard. 3. A one-pack type waterproofing agent for starch-based adhesives, comprising a ketone resin and a cationized polyamide resin.