JPH11106505A - Preparation of aqueous cationic thermosetting resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for preparing an aqueous cationic thermosetting resin solution which can contain a reduced amount of low-molecular organohalogen compounds and can produce an aqueous polyamidepolyamine-epihalohydrin resin solution in a relatively short period of time. SOLUTION: The aqueous cationic thermosetting resin solution is prepared by reacting a polyamidepolyamine with an epihalohydrin in an aqueous solution containing the polyamidepolyamine obtained by reacting an aliphatic dibasic acid and/or a derivative thereof with a polyalkylenepolyamine. In this case, the epihalohydrin is added to the aqueous solution of the polyamidepolyamine so that the equivalent ratio of the epoxy group of the epihalohydrin to the secondary amino group of the polyamidepolyamine (epoxy group/secondary amino group) may fall within the range of 0.8-1.3 thereby to set the concentration of the aqueous solution at 30-70 wt.% in the reaction system, and after initiation of the reaction at 5-30 deg.C, the reaction system is increased gradually in temperature to 50-80 deg.C over 4-8 hours. Then, in the course of or after increasing the temperature, the reaction system is adjusted to have a concentration of the aqueous solution of 20-40 wt.% with or without addition of water into the reaction system and maintained at the same temperature for 0-5 hr.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing an aqueous solution of a cationic thermosetting resin. The resulting cationic thermosetting resin is useful as a wet paper strength enhancer and the like.

[0002]

2. Description of the Related Art Conventionally, a polyamide polyamine-epihalohydrin resin known as a cationic thermosetting resin is produced, for example, by reacting an aqueous solution containing a polyamide polyamine with epichlorohydrin. In the aqueous solution of the polyamide polyamine-epichlorohydrin resin thus obtained, low-molecular-weight organic halogen compounds such as 1,3-dichloro-2-propanol and 3-chloro-1,2-propanediol derived from epichlorohydrin in the production process are present. doing. Such low-molecular-weight organic halogen compounds are desired to be reduced while environmental consciousness is increasing.

[0003] As a method for reducing the amount of low-molecular organic halogen compounds in an aqueous solution of a polyamide polyamine-epihalohydrin resin, for example, a specific ratio of a polyamide polyamine and an epihalohydrin is used, and the reaction temperature of the polyamide polyamine and the epihalohydrin is determined by adding the epihalohydrin to the polyamide polyamine. There is a method in which the temperature is adjusted in two stages of a temperature for adding (primary heat retention) and a temperature for raising the temperature by heating (secondary heat retention) (Japanese Patent Laid-Open No. 2-1708).
No. 25). However, such a method is disadvantageous in manufacturing because the primary heat retention time is very long. The above publication also discloses a method in which the reaction temperature between the polyamide polyamine and the epihalohydrin is kept in the secondary temperature range from the beginning. However, this method does not sufficiently reduce the amount of low-molecular-weight organic halogen compounds.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to produce a cationic thermosetting resin aqueous solution which can reduce low molecular weight organic halogen compounds and produce a polyamide polyamine-epihalohydrin resin aqueous solution in a relatively short time. The aim is to provide a method.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have limited the amount of epihalohydrin used for polyamide polyamine, and furthermore, the reaction system in the step of adding epihalohydrin to polyamide polyamine. The temperature of the polyamide polyamine-
The present inventors have found that the object can be achieved by continuously raising the temperature to a predetermined temperature range for increasing the viscosity of the epihalohydrin resin over an appropriate period of time, and have completed the present invention.

That is, the present invention relates to a method of reacting a polyamide polyamine with an epihalohydrin in an aqueous solution containing a polyamide polyamine obtained by reacting an aliphatic dibasic acid and / or a derivative thereof with a polyalkylene polyamine. In the method for producing an aqueous resin solution, the equivalent ratio of the secondary amino group of the polyamide polyamine to the epoxy group of the epihalohydrin (epoxy group / secondary amino group) is set to 0.8 to
After adding epihalohydrin in a range of 1.3 to adjust the aqueous solution concentration of the reaction system to 30 to 70% by weight, starting the reaction at 5 to 30 ° C, gradually raising the temperature of the reaction system over 4 to 8 hours. While the temperature of the reaction system is raised to 50 to 80 ° C., and after or after the temperature of the reaction system is increased, water is added to the reaction system or the aqueous solution concentration is adjusted to 20 to 40% by weight without adding water.
The present invention relates to a method for producing an aqueous solution of a cationic thermosetting resin, which is maintained at the same temperature for 0 to 5 hours.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The polyamide polyamine used in the present invention is obtained by reacting an aliphatic dibasic acid and / or a derivative thereof with a polyalkylene polyamine. Aliphatic dibasic acids include malonic acid, succinic acid, glutaric acid,
Adipic acid, pimelic acid, suberic acid, azelaic acid,
Sebacic acid and the like, and examples of the aliphatic dibasic acid derivatives include anhydrides of the aliphatic dibasic acids and ester compounds with lower alcohols such as methanol. Also,
Examples of the polyalkylene polyamine include diethylenetriamine, triethylenetetramine, tetraethylenepentamine, iminobispropylamine, and the like.

[0008] The polyamide polyamine comprises 25
The viscosity of a 50% by weight aqueous solution at 200C is 200 to 1000
Cps is preferred. If the aqueous solution viscosity of the polyamide polyamine is lower than 200 cps, the wet paper strength effect of the final product polyamide polyamine-epihalohydrin resin is not sufficient, and if it is higher than 1000 cps, the storage stability of the final product polyamide polyamine-epihalohydrin resin. Tend not to be enough.

The reaction of an aliphatic dibasic acid and / or a derivative thereof with a polyalkylene polyamine is usually carried out by
The reaction temperature is 110 to 2 in the presence or absence of a catalyst such as sulfuric acid, benzenesulfonic acid, and paratoluenesulfonic acid.
This is performed at about 50 ° C. for about 2 to 8 hours. Further, in order to adjust the aqueous viscosity of the obtained polyamide polyamine to the above range, the molar ratio of the aliphatic dibasic acid and / or its derivative to the polyalkylene polyamine is adjusted so that the former: the latter is 1: 2.
It is preferable to use it in the range of about 0.9 to 1.2.

The obtained polyamide polyamine is converted into an aqueous solution and then reacted with epihalohydrin to produce an aqueous solution of polyamide polyamine-epihalohydrin resin. Examples of epihalohydrin include epichlorohydrin, epibromohydrin and the like. The ratio of the epihalohydrin to the polyamide polyamine is not particularly limited. However, since the production amount of the low molecular weight organic halogen compound, which is regarded as environmentally problematic, is small, the epihalohydrin is usually used as a secondary amino group of the polyamide polyamine and epihalohydrin. It is preferable to use such that the equivalent ratio of epoxy group (epoxy group / secondary amino group) falls within the range of 0.8 to 1.3. In order to reduce the amount of the low molecular organic halogen compound generated, the equivalent ratio is preferably 1.2 or less, and the storage stability of the polyamide polyamine-epihalohydrin resin aqueous solution and the wet paper strength effect are taken into consideration. The equivalent ratio is preferably 0.9 or more.

In the reaction between the polyamide polyamine and the epihalohydrin, first, water is added to the obtained polyamide polyamine to adjust the concentration of the aqueous solution in the reaction system to 30 to 70% by weight, and epichlorohydrin is added at 5 to 30 ° C. In addition, start the reaction. Then, the temperature of the reaction system is gradually raised to 50 to 80 ° C. over 4 to 8 hours. As described above, the reaction temperature in the step of adding epihalohydrin to the polyamide polyamine is gradually increased, and the temperature is increased to a predetermined temperature range in which the polyamide polyamine-epihalohydrin resin is thickened. The production of the low-molecular organic halogen compound can be suppressed while performing in a short time. The time for gradually raising the temperature of the reaction system is determined in consideration of the balance between the production time and the effect of suppressing the production of the low-molecular-weight organic halogen compound. The reaction time is preferably 5 hours or more from the viewpoint of the effect of suppressing the production of low-molecular organic halogen compounds. In the above reaction, water is added to the reaction system during or after the temperature of the reaction system is gradually increased to bring the aqueous solution concentration to 20 to 40% by weight. Since the crosslinking reaction is easy to control, it is preferable to adjust the concentration by adding water to the reaction system while gradually raising the temperature of the reaction system.

After the temperature of the reaction system is gradually raised to 50 to 80 ° C., if the aqueous solution does not have the desired viscosity, the temperature is kept at the same temperature. Crosslinking progresses due to heat retention in such a temperature range,
The aqueous solution thickens. The heat retention time at this temperature is from 0 to 5
Time.

When terminating the reaction of the resulting aqueous solution of polyamide polyamine-epihalohydrin resin,
Allow to cool with or without adding water. Since the crosslinking reaction is easily controlled, it is preferable to add water to the reaction system and adjust the concentration of the aqueous solution in the reaction system to about 15 to 30% by weight. In addition, it is preferable that the temperature of the aqueous solution is lower than the above-mentioned heat retention temperature, and the temperature is once kept at about 20 to 60 ° C. By such heat retention, the thickening of the aqueous solution due to crosslinking becomes gentle, and it becomes easy to adjust the product viscosity. The heat retention time in such heat retention is not particularly limited, but usually,
About 0.5 to 4 hours are preferable. In addition, at the time of the above-mentioned heat retention (when the temperature is lowered after the temperature is raised), an inorganic acid such as sulfuric acid, nitric acid, phosphoric acid and the like, and an organic acid such as formic acid and acetic acid are added to the aqueous solution of the polyamide polyamine-epihalohydrin resin. The pH can be adjusted to control the speed of the thickening step.

The reaction between the polyamide polyamine and the epihalohydrin is carried out by subjecting the finally obtained aqueous solution of the polyamide polyamine-epihalohydrin resin to 15 ° C. at 25 ° C.
It is preferable to carry out so that the viscosity of the aqueous solution by weight is in the range of about 10 to 300 cps. From the viewpoint of the performance of the final product as a wet strength agent, the viscosity of the aqueous solution is 50 cps.
The above is more preferable, and from the viewpoint of the storage stability of the final product, it is more preferably 200 cps or less.

The aqueous solution of the polyamide-polyamine-epichlorohydrin resin of the present invention thus obtained is adjusted to an aqueous solution concentration of about 10 to 30% by weight, if necessary, with further addition of an inorganic acid such as sulfuric acid, nitric acid or phosphoric acid. Formic acid,
The pH of the aqueous solution is adjusted to about 2 to 4 by adding an organic acid such as acetic acid to obtain a final product.

[0016]

According to the production method of the present invention, it is possible to reduce the amount of low-molecular organic halogen compounds and to produce an aqueous solution of a polyamide polyamine-epihalohydrin resin in a relatively short time. A manufacturing method can be provided. In addition, the cationic thermosetting resin obtained in the present invention has the same wet paper strength effect as conventionally known, and its aqueous solution has excellent storage stability.

[0017]

EXAMPLES The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to these examples. In each example, “%” is based on weight.

Production Example 1 (Production of Polyamide Polyamine) A flask equipped with a thermometer, a cooler, a stirrer and a nitrogen inlet tube was charged with 730 g (5 mol) of adipic acid and 516 g (5 mol) of diethylenetriamine, and water produced was prepared. After the reaction was carried out at 140 to 190 ° C. for 4 hours, 1100 g of water was gradually added to obtain an aqueous solution of polyamide polyamine having a solid content of 50% and a viscosity of 400 cps (25 ° C.).

Example 1 A flask equipped with a thermometer, a cooler and a stirrer was charged with 400 g of the aqueous solution of the polyamide polyamine obtained in Production Example 1 and 217 g of water, and 83 g of epichlorohydrin (equivalent ratio (epoxy group / secondary amino acid)). Base) = 1.0) at 10 ° C
From 3 to 3 hours while increasing the temperature.
Temperature. Further, the temperature was gradually raised, and the temperature of the reaction system was brought to 65 ° C. over 3 hours. At the time of 45 ° C. and 55 ° C. on the way of gradually raising the temperature of the reaction system to 65 ° C., 216 g of water was added each to make the concentration of the reaction system 25%. Next, it was kept at 65 ° C. for 1 hour. Then water 2
After adding 83 g, the mixture was cooled to 40 ° C and kept warm for 1 hour. Then, 460 g of water, 25 g of 62.5% sulfuric acid, 76
% Formic acid 5 g and cooled, solid content 15%, viscosity 1
An aqueous solution of a polyamide polyamine-epihalohydrin resin at 30 cps (25 ° C.) and pH 2.9 was obtained.

Example 2 A flask equipped with a thermometer, a cooler and a stirrer was charged with 400 g of the aqueous solution of the polyamide polyamine obtained in Production Example 1 and 217 g of water, and 83 g of epichlorohydrin (equivalent ratio (epoxy group / secondary amino acid)). Base) = 1.0) at 10 ° C
From 3 to 3 hours while increasing the temperature.
Temperature. Further, the temperature was gradually raised, and the temperature of the reaction system was brought to 75 ° C. over 3 hours. Further, at the time of 45 ° C. and 55 ° C. in the course of gradually raising the temperature of the reaction system to 75 ° C., 216 g of water was added each to make the concentration of the reaction system 25%. Then, it was kept at 75 ° C. for 30 minutes. Next, after adding 283 g of water, the mixture was cooled to 40 ° C. and kept warm for 30 minutes. Then, 460 g of water, 25 g of 62.5% sulfuric acid, 7
After adding 5 g of 6% formic acid and cooling, an aqueous solution of a polyamide polyamine-epihalohydrin resin having a solid content of 15%, a viscosity of 125 cps (25 ° C.) and a pH of 3.0 was obtained.

Example 3 A flask equipped with a thermometer, a condenser, and a stirrer was charged with 400 g of the aqueous solution of the polyamide polyamine obtained in Production Example 1 and 217 g of water, and 83 g of epichlorohydrin (equivalent ratio (epoxy group / secondary amino acid)). Base) = 1.0) at 10 ° C
From 3 to 3 hours while increasing the temperature.
Temperature. Further, the temperature was gradually raised, and the temperature of the reaction system was raised to 55 ° C. over 3 hours. Further, at the time of 40 ° C. and 50 ° C. in the course of gradually raising the temperature of the reaction system to 55 ° C., 216 g of water was added each to make the concentration of the reaction system 25%. Next, it was kept at 55 ° C. for 2 hours. Then water 2
After adding 83 g, the mixture was kept at 40 ° C. for 1 hour. Then
460 g of water, 25 g of 62.5% sulfuric acid and 5 g of 76% formic acid were added and cooled, and the solid content concentration was 15% and the viscosity was 135 cps.
(25 ° C.), an aqueous solution of a polyamide polyamine-epihalohydrin resin having a pH of 2.8 was obtained.

Comparative Example 1 400 g of the aqueous solution of the polyamide polyamine obtained in Production Example 1 and 217 g of water were charged into a flask equipped with a thermometer, a condenser and a stirrer, and 83 g of epichlorohydrin (equivalent ratio (epoxy group / secondary amino acid) was used. Base) = 1.0) at 10 ° C
From 3 to 3 hours while increasing the temperature.
Temperature. Immediately, 432 g of water was added to adjust the concentration of the reaction system to 25%, the temperature was raised to 65 ° C over 30 minutes, and then the temperature was maintained at 65 ° C for 3 hours. Next, after adding 283 g of water, the mixture was cooled to 40 ° C and kept warm for 1 hour. Then, 460 g of water, 25 g of 62.5% sulfuric acid, 5% of 76% formic acid
g and cooled, solid content concentration 15%, viscosity 120 cp
Thus, an aqueous solution of a polyamide polyamine-epihalohydrin resin having a pH of 2.9 (25 ° C.) was obtained.

Comparative Example 2 400 g of the aqueous solution of the polyamide polyamine obtained in Production Example 1 and 217 g of water were charged into a flask equipped with a thermometer, a condenser and a stirrer, and 83 g of epichlorohydrin (equivalent ratio (epoxy group / secondary amino acid) was used. Base) = 1.0) at 10 ° C
From 3 to 3 hours while increasing the temperature.
Temperature. After keeping the temperature at 30 ° C. for 3 hours, 432 g of water was added to adjust the concentration of the reaction system to 25%, the temperature was raised to 65 ° C. over 30 minutes, and then the temperature was kept at 65 ° C. for 3 hours. Next, after adding 283 g of water, the mixture was cooled to 40 ° C and kept warm for 3 hours. Then, 460 g of water, 62.5
% Sulfuric acid 25 g and 76% formic acid 5 g were added and cooled.
To obtain an aqueous solution of a polyamide polyamine-epihalohydrin resin.

The following evaluation was performed on the aqueous solution of the polyamide-polyamine-epihalohydrin resin obtained in the examples or comparative examples. Table 1 shows the results.

(1) Content of low-molecular-weight organic halogen compound The content was determined by gas chromatography. "%" In Table 1 is "%" of the aqueous solution.

(2) Storage stability The obtained aqueous solution was judged by the properties after standing at 40 ° C. for 2 months. ：: Not gelled. ×: Gelled.

(3) Wet paper strength Pulp (N-BKP / L-BKP = 1/1) is beaten,
Canadian Standard Freeness (CS
F) To the pulp slurry adjusted to 600 ml, the aqueous resin solution obtained in Examples or Comparative Examples (solid content ratio to pulp: 0.3%) was added. The pulp slurry thus obtained was paper-made using a tappi standard sheet machine (square) so as to have a basis weight of 70 g / m ^2, and dewatered with a roll press at 0.5 kg / cm ² . Then, it is dried at 110 ° C. for 4 minutes in a rotary dryer,
65% R. H. Under the above conditions for 24 hours to prepare a hand-made sheet. The wet paper strength of the obtained handmade sheet was measured according to JIS P8135.

[0028]

[Table 1]

Claims (3)

[Claims] 1. A cationic thermosetting resin aqueous solution is produced by reacting a polyamide polyamine with epihalohydrin in an aqueous solution containing a polyamide polyamine obtained by reacting an aliphatic dibasic acid and / or a derivative thereof with a polyalkylene polyamine. In an aqueous solution of a polyamide polyamine, an epihalohydrin in a range where the equivalent ratio of the secondary amino group of the polyamide polyamine to the epoxy group of the epihalohydrin (epoxy group / secondary amino group) is 0.8 to 1.3 is used. In addition, the aqueous solution concentration of the reaction system is 30
After starting the reaction at 5 to 30 ° C, 4%
The temperature of the reaction system was gradually increased to 50 to 80 ° C. over 8 hours while the temperature of the reaction system was raised during or after the temperature of the reaction system was increased or without adding water to the reaction system. A method for producing an aqueous solution of a cationic thermosetting resin, which is kept at 40% by weight and kept at the same temperature for 0 to 5 hours. 2. The method according to claim 1, wherein the viscosity of a 50% by weight aqueous solution of the polyamide polyamine at 25 ° C. is 200 to 1000 cps. 3. The temperature of the reaction system is raised to 50 to 80 ° C., and the temperature is maintained at the same temperature. Then, with or without addition of water, the aqueous solution concentration of the reaction system is 10 to 30% by weight. The method according to claim 1 or 2, wherein the temperature is kept low at 20 to 60 ° C.