JPS5920688B2 - Houkozoku polyamide no seizou hohou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an aromatic polyamide, and its purpose is to produce an aromatic polyamide from an aromatic diamine and an aromatic dicarboxylic acid dichloride.
The object of the present invention is to provide a manufacturing method that can reduce variations in the degree of polymerization from batch to batch.

Aromatic polyamides have useful applications in films, fibers, and paper due to their excellent heat resistance and mechanical properties. However, even if an aromatic polyamide is obtained by reacting an aromatic diamine with an aromatic dicarboxylic acid, the reactivity is low, so it is difficult to obtain a polymer with a high degree of polymerization that can be molded into films, fibers, or paper, and it is difficult to obtain a polymer film with a high degree of polymerization that can be molded into films, fibers, or paper. Even if a polymer that can be used as a molded article is obtained, it is not possible to obtain a polymer with a degree of polymerization high enough to obtain sufficient mechanical properties as a molded article. Therefore, aromatic dicarboxylic acid dihalides with higher activity, especially aromatic dicarboxylic acid chlorides, are generally used, but since the reaction between aromatic diamines and aromatic dicarboxylic acid chlorides occurs rapidly, local reactions may occur. The progress and accompanying heat generation promote side reactions between the aromatic dicarboxylic acid chloride and the amide solvent, causing large variations in the degree of polymerization between batches. Therefore, it is almost impossible to make the polymerization degree uniform for each batch. However, it is well known that the physical properties of aromatic polyamide molded articles are significantly affected by the degree of polymerization of the polymer. For these reasons, it has been difficult to produce aromatic polyamide molded articles of constant quality with a good yield. In order to solve this problem, lowering the entire reaction system to an extremely low temperature lowers the solubility of the aromatic diamine and the produced polymer, and increases the viscosity of the reaction system, making uniform stirring difficult.

Further, lowering the concentration of the reaction components in order to suppress heat generation is undesirable from an economic point of view because the solvent concentration increases and the degree of side reactions between the solvent and the reaction components increases. As a result of extensive research to solve the above problems, the present inventors discovered that after dissolving a specific viscosity stabilizer together with an aromatic diamine in an N-substituted amide polar solvent, aromatic dicarboxylic acid dichloride was dissolved in a certain range. By adding the aromatic dicarboxylic acid chloride at a rate of The inventors have discovered that by adding aromatic dicarboxylic acid dichloride, it is possible to further reduce variation in the degree of polymerization between batches, and have arrived at the present invention.

That is, the present invention provides (1) when producing an aromatic polyamide by adding aromatic dicarboxylic acid dichloride to a solution of an aromatic diamine dissolved in an N-substituted amide polar solvent, the aromatic diamine is 0.2
~1.0 mol% of primary or secondary aliphatic amine and/or aromatic amine is dissolved, and then A weight % of the total amount of aromatic dicarboxylic acid dichloride to be added to the reaction system [however] , A is a value expressed by the following formulas (1), (2) and (3)] The following amount is added, and then the remaining aromatic dicarboxylic acid dichloride is added over a period of 5 minutes or more. (2) When producing an aromatic polyamide by adding aromatic dicarboxylic acid dichloride to a solution in which an aromatic diamine is dissolved in an N-substituted amide polar solvent (hereinafter abbreviated as amide solvent), Dissolving 0.2 to 1.0 mol% of primary or secondary aliphatic amine and/or aromatic amine to the aromatic diamine (hereinafter abbreviated as diamine) together with the aromatic diamine, Thereafter, the following amount of A weight % of the total amount of aromatic dicarboxylic acid dichloride to be added into the reaction system [where A is a value expressed by the following formulas (1), (2) and (3)] was added, then the remaining aromatic dicarboxylic acid dichloride was added over a period of 5 minutes or more, and further aromatic dicarboxylic acid dichloride (hereinafter abbreviated as acid chloride) was added until a substantial increase in the viscosity of the reaction system was no longer observed. This is a method for producing an aromatic polyamide, which is characterized in that the aromatic polyamide is added as follows.

The amide solvent used in the present invention includes N-N-dimethylacetamide, N-N-diethylacetamide, N-
N-dimethylpropionamide, N-N-diethylpropionamide, tetramethylurea, tetraethylurea, N-methyl-2-pyrrolidone, N-methyl-2-piperidone, hexamethylphosphoramide, hexaethylphosphoramide, etc. These can be used alone or in combination.

The diamine used in the present invention refers to a compound represented by the following formula (3) or (4), and the acid chloride refers to a compound represented by the following formula (5) or (6).

H2N-R1-NH2 (3) In the above formula, R,, R2, R3, and R4 represent aromatic rings, and may be the same group or different groups.

Such aromatic rings include phenylene, naphthalene, biphenyl, etc., and one or more hydrogen atoms in the aromatic ring may be replaced by a non-reactive substituent such as rogene or lower alkyl. . X1 and X2 are groups that connect two aromatic rings and are bonds that do not inhibit polymerization, such as ether, thio-ether, carbonyl, sulfone,
sulfoxide, etc., and may be the same or different. These diamines and acid chlorides may be used alone or in combination. Examples of primary or secondary aliphatic amines or aromatic amines used in the present invention include ethylamine, diethylamine, propylamine, aniline, diphenylamine, α- or β-
Examples include naphthylamine and cyclohexylamine.

To produce aromatic polyamide by the method of the present invention,
First, a diamine and a primary or secondary aliphatic amine and/or aromatic amine (hereinafter abbreviated as amine) are dissolved in an amide solvent.

In this case, it is necessary to adjust the diamine concentration to 0.3 mol/l or more and 1.5 mol/l or less. When the diamine concentration is less than 0.3 mol/l, there is a high possibility that side reactions will occur, which becomes a major factor in varying the degree of polymerization of the polymer. On the other hand, if the concentration of diamine exceeds 1.5 mol/l, uniform stirring becomes difficult and impractical. The amount of amine used is 0.2 to 1.0 relative to diamine.
It is necessary that the amount be within the range of mol%. If the amount is less than this range, the viscosity stabilizing effect will be small and the degree of polymerization will vary greatly between batches. On the other hand, if the amount exceeds this range, the variation in the degree of polymerization between batches will be reduced, but only a polymer with a low degree of polymerization will be obtained. Polymerization is carried out by adding acid chloride to the diamine solution obtained as described above, consisting of the diamine, amine, and amide solvent.

The temperature of the reaction system at the start of polymerization needs to be less than 50°C because if it is 50°C or higher, side reactions will occur and the degree of polymerization will be difficult to increase. The acid chloride can be added to the reaction system at once in an amount of not more than A% by weight of the total amount of acid chloride to be added during polymerization, that is, the equimolar amount of acid chloride to the diamine used. Here, A is a value obtained from the above formulas (1), (2), and (3) depending on the temperature of the reaction system at the start of the polymerization reaction and the concentration of aromatic diamine, and the value of A is 100 or more. In the case of , it means that the entire amount of acid chloride to be added during polymerization, that is, 100% by weight, can be added to the reaction system at once. Adding more than A weight % of acid chloride to the reaction system at once is not suitable because the reaction occurs rapidly and it becomes difficult to control the degree of polymerization. This point will be explained with reference to FIG.
Figure 1 shows the ratio of acid chloride added at once to the reaction system out of the total amount of acid chloride to be added during polymerization, that is, the initial addition ratio (wt%) of acid chloride, and the initial addition ratio (wt%) of acid chloride at the start of polymerization. The figure shows the value of (50-t)/TrL determined from the temperature (t) of the reaction system and the concentration (m) of the diamine at the time. The circle in the figure indicates that when polymerization was carried out under these conditions (corresponding to Examples 1, 2, and 4 to 8 described later), there was little variation in the degree of polymerization from batch to batch.
The X mark indicates the case where polymerization was carried out under the conditions (Comparative Example 3 described below).
It corresponds to ~7. ) indicates that the degree of polymerization varies greatly from batch to batch. From Figure 1, in order to reduce the variation in the degree of polymerization from batch to batch, the initial addition ratio of acid chloride (wt%
) is the value (A) expressed in 0.89 (50-t)/m depending on the temperature of the reaction system at the start of polymerization (t) and the concentration of diamine.
It is clear that it must be less than or equal to:

After adding the amount of A weight % or less, the remaining acid chloride must be added over a period of 5 minutes or more. It is difficult to control the degree of polymerization when adding in a shorter time than this.
This is not suitable because the degree of polymerization varies greatly between batches.
An aromatic polyamide can be obtained by separating the polymer from the reaction solution after completion of polymerization by a conventional method, washing with water, and drying.

The desired aromatic polyamide can be produced in the above manner, but after adding the remaining acid chloride over a period of 5 minutes or more, the viscosity of the reaction solution is continuously detected by the stirring torque, and the torque is substantially increased. By adding additional acid chloride until no significant increase is observed, variations in the degree of polymerization between batches can be further reduced.

In this case as well, it is preferable to add the acid chloride little by little over time. The acid chloride used in the present invention may be in bulk, powder, or molten form, or may be obtained by dissolving the acid chloride in an inert solvent such as benzene, toluene, or tetrahydrofuran. ~ According to the method of the present invention, it is possible to reduce variations in the degree of polymerization from batch to batch when producing aromatic polyamide from diamine and acid chloride.

Since the aromatic polyamide produced by the method of the present invention has little variation in the degree of polymerization from batch to batch, there is no problem in molding, and it can be used as molded products such as films, fibers, and paper with uniform quality. It can fully demonstrate its excellent properties. Hereinafter, the present invention will be explained in more detail with reference to Examples.

In the examples, the logarithmic viscosity (ηInh) was used as a guideline for the degree of polymerization. It was measured by a conventional method using an Ostwald viscometer at ℃, and obtained according to the following formula.Example 1 Metaphenylenediamine 12.9y1β-naphthylamine 0.086V (0 .50 mol % to diamine) was dissolved and cooled to 2°C.

(Diamine concentration: 1.19 mol/l) In this case, the value of A in formula (1) was 35.9. Powdered isophthalic acid chloride 7.007 (corresponding to 28.9% by weight of the amount to be added) was added to this diamine solution over 10 seconds, and then the remaining 14.257 isophthalic acid chloride was added over 8 minutes. and added. After addition of isophthalic acid chloride, stirring was continued for 1 hour, and the resulting reaction solution was poured into water to precipitate a polymer. Subsequently, the solvent was thoroughly extracted with hot water, and the mixture was dried under reduced pressure to obtain a polymer. Polymerization was repeated 5 times in the same manner, and the logarithmic viscosity of the obtained polymer was measured and found to be in the range of 1.44 to 1.56, with a standard deviation of 0.03. Example 2 N-methylpyrrolidone 21 and paraphenylenediamine 5
3.21, metaphenylenediamine 161.47 and aniline 0.93V were dissolved and cooled to 5°C.

(Diamine concentration: 0.99 mol/l) In this case, the value of A in formula (1) was 40.1. Powdered isophthalic acid chloride 121.47 (corresponding to 30% by weight of the amount to be added) was added to the obtained diamine solution over 10 seconds, and the remaining 283.17 isophthalic acid chloride was added over 10 minutes. Added. After the addition of isophthalic acid chloride, stirring was continued for an additional hour, and a polymer was obtained in the same manner as in Example 1. Polymerization was repeated 5 times in the same manner. When the logarithmic viscosity of the polymer thus obtained was measured, it was in the range of 2.21 to 2.32, with a standard deviation of 0.02.
It was hot. Example 3 Metaphenylenediamine 12.9 ft 1 aniline 0.054 r (0.0
．． 49 mol% of diamine) and 100 WLI of dimethylacetamide which had been thoroughly dehydrated and dried were charged to dissolve the diamine, and then cooled to 2°C.

(Diamine concentration: 1.19 mol/l) In this case, the value of A in formula (1) was 35.9. Powdered isophthalic acid chloride 4.2y (corresponding to 17.3% by weight of the amount to be added) was added to this diamine solution over 10 seconds, and further 20.0f7 was added over 10 minutes. During this time, the value on the torque meter was rising, and isophthalic acid chloride was added little by little until the value on the torque meter stopped rising. After continued stirring for 1 hour, a polymer was obtained in the same manner as in Example 1. Polymerization was repeated 5 times in the same manner. The total amount of isophthalic acid chloride used ranged from 24.38 to 24.637, corresponding to an excess of 0.5 to 1.6% over the amount to be added. When the logarithmic viscosity of the polymer thus obtained was measured, it was in the range of 1.52 to 1.58, with a standard deviation of 0.01. Example 4 Metaphenylenediamine 900V1 paraphenylenediamine 80y and β-naphthylamine 5.77% (0.44 mol % to diamine) were dissolved in 151 N-methylpyrrolidone and cooled to 5°C.

(Diamine concentration 1.60 mol/.e) In this case (1)
The value of A in the formula was 59.3. To this diamine solution, 10007 (corresponding to 54.3% by weight of the amount to be added) of a molten mixture of terephthalic acid chloride and isophthalic acid chloride (1:1 molar ratio) was added over 30 seconds, and then 8407 was added. The mixture was added over a period of 10 minutes, and then the mixed acid chloride was added while keeping the reaction solution at 40° C. until no increase in the viscosity of the reaction solution was observed. Polymerization was repeated 5 times in the same manner. The total amount of acid chloride used ranged from 1849 to 18667, corresponding to a 0.4 to 1.2% excess of the amount to be added. Then, the logarithmic viscosity of the obtained polymer was measured.
．． The range was 17 to 2.26, and the standard deviation was 0.01. Comparative Example 1 Polymerization was repeated five times in the same manner as in Example 1, except that the entire amount of isophthalic acid chloride to be added was added in 3 minutes.

The obtained polymer had a low logarithmic viscosity of 1.05 to 1.32, and a large standard deviation of 0.08.

〉*Comparative Example 2 Polymerization was repeated five times in the same manner as in Example 1 except that β-naphthylamine was not used and the amount of diamine was changed to 13.07.

The obtained polymer had a logarithmic viscosity of 1.87 to 2.83, and a standard deviation of 0.28.

Examples 5 to 8 250 m equipped with high-speed rotating stirring blades and capable of nitrogen replacement
Metaphenylenediamine and N-methyl-2-pyrrolidone were charged in the amounts shown in Table 1 into flask No. 1 (however, flask No. 301 was used only in Example 8), and after dissolving them, β in the amount shown in Table 1 was charged. - Naphthylamine was added, reacted and then cooled to the initial temperature shown in Table 1.

Approximately 5 meshes of granular isophthalic acid dichloride were added to this diamine solution 5 in an amount shown as the initial addition amount in Table 1,
Further, the remaining amount to be added was added over the time shown in Table 1, and a polymer was obtained in the same manner as in Example 1. Polymerization was repeated five times in the same manner. The logarithmic viscosity and standard deviation of the obtained polymer O - were as shown in Table 1.
In Table 1, the initial addition ratio is the ratio of the intended addition amount to the amount of isophthalic acid dichloride to be added. Comparative Example 3 - Initial addition ratio of physophthalic acid dichloride to A of formula (1)
Polymers were obtained in the same manner as in Examples 5 to 8, except that the amount exceeded the value of .

The logarithmic viscosity and standard deviation of the obtained polymer are shown in Table 2 together with the polymerization conditions. As is clear from Table 2, the logarithmic viscosity of the polymer was lower than in Examples 5 to 8, and the variation in the five polymerizations was large.

[Brief explanation of the drawing]

FIG. 1 illustrates the initial addition ratio (wt%) of acid chloride in Examples and Comparative Examples relative to (50-t)/m.

Claims (1)

[Claims] 1. When producing aromatic polyamide by adding aromatic dicarboxylic acid dichloride to a solution of aromatic diamine dissolved in N-substituted amide polar solvent, 0.0. 2 to 1.0 mol% of primary or secondary aliphatic amine and/or aromatic amine is dissolved, and then A weight % of the total amount of aromatic dicarboxylic acid dichloride to be added into the reaction system [ however,
A is a value expressed by the following components (1), (2), and (3)] The following amount is added, and then the remaining aromatic dicarboxylic acid dichloride is added over a period of 5 minutes or more. A method for producing an aromatic polyamide. A=0.89(50-t)/m(1) 0.3≦m≦1.5(2) t<50(3) However, t: Temperature of the reaction system at the start of the reaction (°C) m: Concentration of aromatic diamine at the start of reaction (mol/l) 2 When producing aromatic polyamide by adding aromatic dicarboxylic acid dichloride to a solution of aromatic diamine dissolved in N-substituted amide polar solvent, Aromatic dicarboxylic acid dichloride to be dissolved in 0.2 to 1.0 mol% of primary or secondary aliphatic amine and/or aromatic amine based on aromatic diamine, and then added to the reaction system. A weight% of the total amount [however,
A is a value expressed by the following formulas (1), (2), and (3)] The following amounts were added, and then the remaining aromatic dicarboxylic acid dichloride was added over a period of 5 minutes or more, and the reaction was continued. A method for producing an aromatic polyamide, which comprises additionally adding aromatic dicarboxylic acid dichloride until substantially no increase in the viscosity of the system is observed. A=0.89(50-t)/m(1) 0.3≦m≦1.5(2) t<50(3) However, t: Temperature of the reaction system at the start of the reaction (°C) m: Concentration of aromatic diamine at the start of reaction (mol/l)