JP3456288B2 - Method for producing aqueous solution of cationic thermosetting resin - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an aqueous cationic thermosetting resin solution used as a wet strength improver for paper.

[0002]

2. Description of the Related Art The usefulness of polyamide polyamine-epihalohydrin resins as agents for improving the strength of paper, particularly the wet strength, is disclosed in, for example, Japanese Examined Patent Publication No. 58-53653.
(= USP 4,287,110) and the like, and is publicly known. Such a polyamide polyamine-epihalohydrin resin is generally produced by reacting an aliphatic dicarboxylic acid with a polyalkylene polyamine and further reacting an epihalohydrin, but in many cases, a product contains a large amount of a low molecular weight organohalogen compound. For example, when epichlorohydrin was used, it contained a large amount of 1,3-dichlorohydrin and monochlorohydrin. The wet strength improver is added to the aqueous suspension of pulp when making paper from the aqueous suspension of pulp, but the low molecular weight organohalogen compound as described above is not adsorbed to the pulp and is directly contained in the waste water. In recent years, it has been desired to reduce the amount of such low molecular weight organohalogen compounds because they flow out.

JP-A-2-170825 (= USP 5,017,642)
Describes a method for producing an aqueous solution of a polyamide polyamine-epihalohydrin resin by controlling the amount of epihalohydrin used, the solid content concentration in the reaction system and the reaction temperature. By this method, the amount of the low molecular weight organic halogen compound contained in the aqueous resin solution can be reduced, but further reduction is desired.

[0004]

DISCLOSURE OF THE INVENTION The object of the present invention is a cationic heat which is useful as a wet strength improver for paper, has good storage stability even at a high concentration, and has a low content of low molecular weight organohalogen compounds. The purpose is to produce an aqueous curable resin solution. The inventors of the present invention have solved the problem by a means different from Japanese Patent Laid-Open No. 2-170825, and further reduce the content of low molecular weight organohalogen compounds even in the resin aqueous solution produced by the method described in the publication. The present invention has been completed as a result of intensive research to find a method capable of achieving the above.

[0005]

Means for Solving the Problems That is, the present invention is to heat-condense an aliphatic dicarboxylic acid compound and a polyalkylene polyamine to form a polyamide polyamine, and to react the polyamide polyamine with epihalohydrin in an aqueous solution. -Providing a method for producing an aqueous solution of a cationic thermosetting resin, which comprises the steps of forming an epihalohydrin resin and evaporating a part of water in the system during or after the reaction with epihalohydrin. is there.

The reaction itself for obtaining the polyamide polyamine-epihalohydrin resin to be treated in the present invention is known from JP-B-58-53653 and JP-A-2-170825, and the method described therein is applied. This resin can be manufactured.

The term "aliphatic dicarboxylic acid compound as a raw material" is meant to include not only free acid but also its ester, acid anhydride and the like. Examples of free aliphatic dicarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid and the like, and examples of esters include lower alkyl esters such as diethyl malonate and dimethyl adipate. Examples of the acid anhydride include succinic anhydride and glutaric anhydride.
Industrially, adipic acid is preferably used.

The polyalkylene polyamine means two primary amino groups and at least one secondary amino group in the molecule.
It is a compound having a single amino group and a primary amino group and a secondary amino group, and when there are two or more secondary amino groups, a compound having an alkylene bond between them. Specifically, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, iminobispropylamine, 3-azahexane-1,6-diamine, 4,7-diazadecane-
1,10-diamine etc. are mentioned.

A polyamide polyamine is obtained by reacting an aliphatic dicarboxylic acid compound with a polyalkylene polyamine. At this time, 1 mol of polyalkylene polyamine was added to 1 mol of the aliphatic dicarboxylic acid compound.
It is preferably used in the range of from about 1.2 mol.

Further, within the range that does not impair the performance of the present invention,
Aminocarboxylic acid compounds can also be used in combination. The term "aminocarboxylic acid compound" as used herein is meant to include compounds having both an amino group and a carboxyl group in the molecule, as well as those in which the carboxyl group is esterified, those having an intramolecular amide bond, and the like. . Examples of aminocarboxylic acid compounds include free acids such as glycine, alanine and aminocaproic acid, lower alkyl esters thereof, and lactams such as caprolactam.

In the polycondensation of the aliphatic dicarboxylic acid compound and the polyalkylene polyamine, a catalyst such as mineral acid or sulfonic acid can be used. Examples of the mineral acid include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and the like, and examples of the sulfonic acid include benzenesulfonic acid, paratoluenesulfonic acid, and the like. Of these, sulfuric acid or sulfonic acid is preferably used. When a catalyst is used, the amount thereof is usually in the range of 0.05 to 0.1 mol, preferably 0.01 to 0.05, based on 1 mol of the polyalkylene polyamine.
It is in the molar range.

The polyamidation reaction (polycondensation) is 100 to
It is suitable to carry out at a temperature in the range of 250 ° C., preferably in the range of 130 to 200 ° C., and usually it is carried out while removing the water or alcohol generated. And 50% by weight
It is preferable to continue the reaction until the viscosity of the aqueous solution at 25 ° C becomes 400 to 1000 cP.

The polyamide polyamine thus obtained is then subjected to reaction with epihalohydrin in aqueous solution. Examples of the epihalohydrin used here include epichlorohydrin and epibromohydrin,
Epichlorohydrin is industrially preferable. The reaction between polyamide polyamine and epihalohydrin is carried out in an aqueous solution having a solid content concentration of 10 to 70% by weight, preferably 25 to 60% by weight. It is suitable to use epihalohydrin in the range of 0.85 to 2 mol, preferably 1 to 1.8 mol, based on 1 mol of the secondary amino group in the polyamide polyamine. The reaction temperature is preferably in the range of 10 to 80 ° C.

The reaction is also carried out primarily at a relatively low temperature, then secondarily at a relatively high temperature, and so on.
It is also preferable to perform it in stages. In this case, the temperature of the primary reaction is 10 to 55 ° C, preferably 10 to 40 ° C, and the temperature of the secondary reaction is 30 to 80 ° C, preferably 40 to 70 ° C. . In the secondary reaction, it is preferable that the solid content concentration is the same as that in the primary reaction or the concentration is adjusted to be lower than that.

By this reaction, polyamide polyamine-
The epihalohydrin resin is obtained in the form of an aqueous solution.
The reaction end point is preferably reached when the viscosity at 25 ° C. when the solid content concentration of the product is 15% by weight becomes 10 to 150 cP. When the aqueous resin solution in the reaction reaches such a desired viscosity, it is diluted with water if necessary, and then an acid such as hydrochloric acid, sulfuric acid, phosphoric acid, formic acid, acetic acid is added to adjust the pH to 3 to 5, and the polyamide polyamine is added. Obtaining an aqueous solution of epihalohydrin resin.

In the present invention, part of the water in the system is evaporated during or after the reaction of epihalohydrin is in progress. The concentration operation for evaporating water can be performed under normal pressure or reduced pressure,
It is preferably carried out under reduced pressure of mmHg. At this time, it is possible to employ a method in which the solid content concentration in the reaction solution is relatively low, that is, the reaction is carried out in the presence of a relatively large amount of water, and a part of the water is evaporated during or after the reaction. However, it is preferable to employ a method in which water is added during or after the reaction and water is evaporated in parallel with or after that.

When water is added, the water may of course be liquid or steam. The water may be added all at once, but it is also preferable to add it continuously. The amount of water added here is based on the total amount of the water and the reaction solution, and the amount of solid content (the total of unreacted components and resin when added during the reaction, the resin when added after the reaction) is 1 The solid content is preferably in the range of 5 to 20% by weight, and more preferably in the range of 5 to 20% by weight. The solid content at this time is 30
If it exceeds 1% by weight, the effect of reducing the content of the low molecular weight organic halogen compound is not so great, and if it is less than 1% by weight, a large amount of water must be evaporated in proportion to it, which is industrially disadvantageous. . If you add water,
It is preferable to evaporate approximately the same amount of water as the added water or more.

When water is added to the undiluted resin solution obtained by the reaction and then water is evaporated, the evaporation (concentration) operation can be carried out either under normal pressure or under reduced pressure, but preferably under reduced pressure of 10 to 400 mmHg. Below, it is carried out at a temperature of 20 to 70 ° C. Further, it is also preferable to carry out a concentration operation in which water in the resin stock solution is evaporated while continuously adding liquid water or water vapor to the resin stock solution obtained by the reaction. In this case, the amount of water added is preferably 10 to 1000 parts by weight, and more preferably 50 to 500 parts by weight, based on 100 parts by weight of the original resin stock solution. In the case of concentrating while adding water as described above, this operation can be carried out under normal pressure or under reduced pressure, but it is preferably carried out under reduced pressure of 10 to 400 mmHg and at a temperature of 20 to 70 ° C as in the above.

When water is added during the reaction, it can be carried out according to the above description. When the concentration operation is performed during the reaction, this concentration operation is performed while maintaining the preferable reaction temperature described above. Therefore, it is generally preferable to perform the concentration operation while proceeding the reaction under reduced pressure. Of course, it is also possible to add water during the reaction and perform a concentration operation after the reaction is completed.

Thus, by performing an operation of evaporating a part of water in the system during or after the reaction with epihalohydrin, the content of the low molecular weight organohalogen compound in the aqueous resin solution is remarkably reduced. It The aqueous solution of the cationic thermosetting resin thus obtained imparts an excellent effect of enhancing the wet strength to paper and is excellent in stability over time, like the one produced by the known method.

The aqueous resin solution obtained by the method of the present invention is used not only as an agent for improving the wet strength of paper, but also for improving the retention rate of the filler added during the papermaking process and the papermaking speed. It can also be used as a drainage improver or a precipitation coagulant for removing fine particles in wastewater such as industrial wastewater.

[0022]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto. Unless otherwise specified,% in the examples means% by weight. As the low molecular weight organohalogen compound contained in the polyamide polyamine-epihalohydrin resin, dihalohydrin is usually the most abundant, so in the following examples, dichlorohydrin was used as a representative example, and its quantification was performed using gas chromatography. . Further, both pH and viscosity are values measured at 25 ° C.

Synthesis Example 1 206 g of diethylenetriamine (2.0 g) was placed in a 1 liter four-necked flask equipped with a thermometer, a reflux condenser and a stir bar.
Mol) and 292 g (2.0 mol) of adipic acid, and the reaction was carried out at 155 to 165 ° C. for 20 hours while removing water. Then, add water to adjust the concentration to 50% and increase the viscosity to 5
A 90 cP polyamide polyamine aqueous solution was obtained. In a separate flask, add this 50% polyamide polyamine aqueous solution 128
g (0.3 mol as diethylenetriamine) and water 1
37 g was charged and 44 g (0.48 mol) of epichlorohydrin was added. Insulates at 60-65 ℃ and has a viscosity of 450
When it reached cP, the pH was adjusted to 3.5 with sulfuric acid, and water was added to dilute it to a concentration of 15%. The viscosity was 43 cP.
A resin aqueous solution of was obtained. The dichlorohydrin contained in this was 8.2% with respect to the resin content.

Synthesis Example 2 Diethylenetriamine 2 was placed in the same reaction vessel as in Synthesis Example 1.
06 g (2.0 mol), adipic acid 278 g (1.9 mol), water 10 g and 98% sulfuric acid 4 g (0.04 mol)
Was charged and reacted at 150 to 160 ° C. for 15 hours while draining water. Then, water was added to adjust the concentration to 50% to obtain a polyamide polyamine aqueous solution having a viscosity of 680 cP. In a separate flask, add this 50% polyamide polyamine aqueous solution 1
29 g (0.3 mol of diethylenetriamine) and 118 g of water were charged, and 44 g of epichlorohydrin (0.4
8 mol) was added. Keep it warm at 60-65 ° C and have a viscosity of 4
When it reached 50 cP, adjust the pH to 3.6 with sulfuric acid,
When water was further added to dilute it to a concentration of 15%, the viscosity became 4
An aqueous resin solution of 4 cP was obtained. The dichlorohydrin contained in this was 8.1% with respect to the resin content.

Synthesis Example 3 A flask was charged with 129 g of a 50% polyamide polyamine aqueous solution (0.3 mol as diethylenetriamine) and 118 g of water synthesized in the previous stage of Synthesis Example 2 and the internal temperature was 40.
While keeping the temperature below ℃, epichlorohydrin 44g (0.4
8 mol) was added and the mixture was kept warm at 35 to 40 ° C. for 3 hours. After that, the temperature was raised and kept at 60 to 65 ° C, and when the viscosity reached 450 cP, the pH was adjusted to 3.3 with sulfuric acid, and water was further added to dilute it to a concentration of 30%. was gotten. The dichlorohydrin contained in this was 7.9% with respect to the resin content.

Synthesis Example 4 Diethylenetriamine 2 was placed in the same reaction vessel as in Synthesis Example 1.
06 g (2.0 mol), adipic acid 278 g (1.9 mol)
Then, 7 g (0.04 mol) of paratoluenesulfonic acid was charged, and the mixture was reacted at 150 to 160 ° C. for 15 hours while removing water. After that, add water to adjust the concentration to 50% and increase the viscosity to 6
A 40 cP polyamide polyamine aqueous solution was obtained. In a separate flask, add this 50% polyamide polyamine aqueous solution 129
g (0.3 mol as diethylenetriamine) and water 1
18 g was charged and 44 g (0.48 mol) of epichlorohydrin was added. Insulates at 60-65 ℃ and has a viscosity of 450
When it reached cP, the pH was adjusted to 3.5 with sulfuric acid, and water was added to dilute it to a concentration of 25%.
An aqueous resin solution of cP was obtained. The dichlorohydrin contained in this was 8.3% with respect to the resin content.

Synthesis Example 5 A flask was charged with 129 g of a 50% polyamide polyamine aqueous solution (0.3 mol as diethylenetriamine) and 117 g of water synthesized in the previous step of Synthesis Example 4, and the internal temperature was 30.
33g of epichlorohydrin (0.3
6 mol) was added and the mixture was kept warm at 30 to 35 ° C. for 3 hours. After that, the temperature was raised and kept at 60 to 65 ° C., when the viscosity reached 400 cP, the pH was adjusted to 3.4 with sulfuric acid, and water was further added to dilute it to a concentration of 15%. was gotten. The dichlorohydrin contained in this was 5.2% with respect to the resin content.

Synthesis Example 6 In the same reaction vessel as in Synthesis Example 1, 262 g (2.0 mol) of iminobispropylamine and 278 g (1.9 g of adipic acid) were added.
Mol) and 98% sulfuric acid 4 g (0.04 mol),
The reaction was performed at 150 to 160 ° C. for 15 hours while removing water. After that, add water to adjust the concentration to 50% and increase the viscosity to 710.
An aqueous polyamide polyamine solution of cP was obtained. In another flask, 147 g of this 50% polyamide polyamine aqueous solution
(0.3 mol as iminobispropylamine) and 145 g of water were charged, and 44 g of epichlorohydrin (0.48)
Mol) was added. Keep it warm at 60-65 ℃
When it reached 0 cP, the pH was adjusted to 3.6 with sulfuric acid, and water was added to dilute it to a concentration of 15%.
An aqueous resin solution of cP was obtained. The dichlorohydrin contained in this was 8.2% with respect to the resin content.

Synthesis Example 7 Diethylenetriamine 1 was placed in the same reaction vessel as in Synthesis Example 1.
Then, 03 g (1.0 mol), 139 g (0.95 mol) of adipic acid and 57 g (0.5 mol) of caprolactam were charged and reacted at 150 to 160 ° C. for 15 hours while removing water. After that, add water to adjust the concentration to 50% and increase the viscosity to 53
A 0 cP polyamide polyamine aqueous solution was obtained. In a separate flask, add 158 g of this 50% polyamide polyamine aqueous solution.
(0.3 mol as diethylenetriamine) and water 19
2 g was charged and 50 g (0.54 mol) of epichlorohydrin was added. Insulated at 60-65 ℃, viscosity is 80cP
When the pH reached, the pH was adjusted to 3.5 with hydrochloric acid, and the concentration was further adjusted to 30% to obtain a resin aqueous solution having a viscosity of 81 cP. The dichlorohydrin contained in this was 7.8% with respect to the resin content.

Example 1 A resin stock solution 100 obtained in Synthesis Example 1 was placed in a flask equipped with a distillation device connected to a vacuum pump, a thermometer and a stir bar.
g, charged with 100 g of water, and added at 55 to 60 ° C.
/ 100-150 mmHg and concentrated under reduced pressure until about 100 g of water was distilled out. Then, when the concentration was adjusted to 15%, an aqueous resin solution having a viscosity of 44 cP was obtained, and the dichlorohydrin contained in the aqueous solution was 2.1% based on the resin content.

Example 2 A flask similar to that of Example 1 was charged with 100 g of the resin stock solution obtained in Synthesis Example 1, and 200 g of water was continuously added to the flask at 55 to 60 ° C./100 to 150 mmHg for the addition rate and distillation. The concentration was carried out under reduced pressure by adjusting the output rates to be almost equal. After that, when the concentration was adjusted to 15%, the viscosity was 45 cP
A resin aqueous solution of was obtained, and the dichlorohydrin contained therein was 0.2% based on the resin content.

Example 3 A flask similar to that used in Example 1 was charged with 100 g of the resin stock solution obtained in Synthesis Example 2, and 200 g of water was added to the flask.
Concentration under reduced pressure was carried out at -45 ° C / 50-100 mmHg until about 200 g of water was distilled. Then, when the concentration was adjusted to 15%, an aqueous resin solution having a viscosity of 44 cP was obtained, and the dichlorohydrin contained therein was 1.8% with respect to the resin content.

Example 4 100 g of the resin stock solution obtained in Synthesis Example 2 was charged in the same flask as in Example 1, and 100 g of steam was added to the flask.
Concentration under reduced pressure was carried out at 55-60 ° C./100-150 mmHg until about 100 g of water was distilled. After that, when the concentration was adjusted to 15%, an aqueous resin solution having a viscosity of 46 cP was obtained, and dichlorohydrin contained in the aqueous solution was 0.6% with respect to the resin content.
%Met.

Example 5 A flask similar to that of Example 1 was charged with 100 g of the resin stock solution obtained in Synthesis Example 3, and 100 g of water was further added to the flask.
Concentration under reduced pressure was carried out at -60 ° C / 100-150 mmHg until about 100 g of water was distilled. After that, when the concentration was adjusted to 30%, a resin aqueous solution having a viscosity of 315 cP was obtained, and dichlorohydrin contained therein was 2.0% with respect to the resin content.
Met.

Example 6 A flask similar to that of Example 1 was charged with 100 g of the resin stock solution obtained in Synthesis Example 3, and 100 g of water was continuously added to the flask at 55-60 ° C./100-150 mmHg at an addition rate and distillation. The concentration was carried out under reduced pressure by adjusting the output rates to be almost equal. After that, when the concentration was adjusted to 30%, the viscosity was 312 cP
As a result, an aqueous resin solution was obtained, and the dichlorohydrin contained therein was 1.1% based on the resin content.

Examples 7 to 10 Using 100 g of each resin stock solution obtained in Synthesis Examples 4 to 7, 100 g of water was added in the same manner as in Example 1, and 5
The mixture was concentrated under reduced pressure at 5 to 60 ° C./100 to 150 mmHg until about 100 g of water was distilled out, and the concentration was adjusted to a predetermined value. The results are summarized in Table 1.

Example 11 5 obtained in the previous stage of Synthesis Example 1 was placed in the same flask as in Example 1.
128 g of a 0% polyamide polyamine aqueous solution (0.3 mol as diethylenetriamine) and 118 g of water were charged, and 44 g (0.48 mol) of epichlorohydrin was added. After incubating at 40-45 ℃ for 3 hours, 60-65 ℃
The temperature is raised to 200 ° C., water is continuously added at this temperature, and 200 to 30
The addition rate and the distillation rate were adjusted to be substantially equal at 0 mmHg, and the reaction was performed while concentrating under reduced pressure. Viscosity is 480cP
At this point, the pH was adjusted to 3.5 with sulfuric acid, and water was added to adjust the concentration to 15%. As a result, an aqueous resin solution having a viscosity of 48 cP was obtained. The dichlorohydrin contained in this was 0.7% based on the resin content.

Example 12 In a flask similar to that of Example 1, 5 obtained in the previous stage of Synthesis Example 2 was used.
129 g of 0% polyamide polyamine aqueous solution (0.3 mol as diethylenetriamine) and 118 g of water were charged, and 44 g (0.48 mol) of epichlorohydrin was added. After incubating at 40-45 ℃ for 3 hours, 60-65 ℃
Temperature is raised to 200 ° C., and steam is continuously added at this temperature,
The amount of liquid in the reaction system was adjusted to be substantially constant at 300 mmHg, and the reaction was performed while concentrating under reduced pressure. Viscosity is 430cP
At this point, the pH was adjusted to 3.5 with sulfuric acid, and water was added to adjust the concentration to 30%. As a result, an aqueous resin solution having a viscosity of 331 cP was obtained. The dichlorohydrin contained in this was 0.8% with respect to the resin content.

Reference Example Using the respective resin aqueous solutions obtained in Examples 1 to 12 and the respective resin aqueous solutions obtained in Synthesis Examples 1 to 7 for comparison, a papermaking test by the TAPPI standard papermaking method was carried out as follows. I went under the conditions. The wet breaking length of the obtained paper was measured according to JIS P 8135, and the results are shown in Table 1.

Papermaking conditions Pulp used: N-BKP / L-BKP = 1/1 Beating degree: 420cc Resin addition amount: 0.4% (solid content, dry pulp) Drying condition: 110 ° C, 4 minutes Average of papermaking Rice basis weight: 60 g / m ²

[0041]

[Table 1]

[0042]

According to the present invention, the amount of low molecular weight organohalogen compound such as dihalohydrin contained in the aqueous resin solution can be remarkably reduced by carrying out the operation of evaporating water during or after the reaction, and moreover, it can be obtained. The aqueous solution of the cationic thermosetting resin imparts to the paper the same excellent wet strength enhancing effect as the polyamide polyamine-epihalohydrin resin produced by a known method, and is also excellent in stability over time.

Claims (7)

(57) [Claims] 1. An aliphatic dicarboxylic acid compound and a polyalkylene polyamine are heated and condensed to form a polyamide polyamine, and the polyamide polyamine is reacted with epihalohydrin in an aqueous solution to form a polyamide polyamine-epihalohydrin resin, and epihalohydrin. A method for producing an aqueous cationic thermosetting resin solution, which comprises evaporating a part of water in the system during or after the reaction with. 2. The method of claim 1, further comprising adding water during or after the reaction with epihalohydrin. 3. The method according to claim 2, wherein the water is evaporated after the water is added. 4. A method of evaporating water while adding water.
The method described. 5. The method according to claim 4, wherein the added water is liquid water or steam. 6. The method according to claim 2, wherein water is added so that the amount of solid content is 1 to 30% by weight based on the total amount of water to be added and the reaction solution. 7. The method according to claim 1, wherein the water is evaporated under reduced pressure.