JPS591296B2 - 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 one tries to obtain aromatic polyamide by reacting aromatic diamine and 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, and paper. Even if such a polymer could be obtained, it would not be 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 halides, especially aromatic dicarboxylic acid chlorides, which have higher activity are generally used, but the reaction between aromatic diamines and aromatic dicarboxylic acid chlorides occurs rapidly, resulting in a localized reaction. 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 of each batch the same. 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 a very low temperature lowers the solubility of the aromatic diamine and the resulting polymer, and also 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 not desirable from an economical point of view since 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 reacting an aromatic diamine with a specific viscosity stabilizer in an N-substituted amide polar solvent, aromatic dicarboxylic acid dichloride was It is possible to reduce variation in the degree of polymerization between batches by adding at a certain rate and polymerizing, and after adding a predetermined amount of aromatic dicarboxylic acid chloride, until no increase in the viscosity of the reaction system is observed. It was discovered that the variation in the degree of polymerization between batches could be further reduced by successively adding aromatic dicarboxylic acid dichloride, and the present invention was achieved based on this finding.

That is, the present invention provides (1) when producing aromatic polyamide by adding aromatic dicarboxylic acid dichloride to a solution of aromatic diamine dissolved in N-substituted amide polar solvent, aliphatic monocarboxylic acid halide and/or aromatic Monocarboxylic acid halide to aromatic diamine from 0.2 to
A weight % of the total amount of aromatic dicarboxylic acid dichloride to be added at 1.0 mol % and reacted with the aromatic diamine, and then added into the reaction system [However, A is the following (1)
, (2) and (3)] is added in the following amounts, and then the remaining aromatic dicarboxylic acid dichloride is added over a period of 5 minutes or more. and (2) aromatic diamine with N
Substituted amide polar solvent (hereinafter abbreviated as amide solvent).

) When producing an aromatic polyamide by adding aromatic dicarboxylic acid dichloride to a solution dissolved in acetate, the ratio of aliphatic monocarboxylic acid halide and/or aromatic monocarboxylic acid halide to aromatic diamine is 0.2 to 1. .0 mol% of the aromatic diamine (hereinafter abbreviated as diamine)
A% by weight of the total amount of aromatic dicarboxylic acid dichloride to be reacted with and then added to the reaction system [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 chloride was added over a period of 5 minutes or more, and the reaction system aromatic dicarboxylic acid dichloride (hereinafter abbreviated as acid chloride) until substantially no increase in viscosity is observed.
This is a method for producing an aromatic polyamide characterized by additionally adding. However, t: temperature of the reaction system at the start of the reaction (°C) m: concentration of aromatic diamine at the start of the reaction (mol/l) As the amide solvent used in the present invention, 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 may 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).

In the above formula, R1, 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 the aromatic ring has one or more hydrogen atoms,
j To produce an aromatic polyamide by the method of the present invention, a diamine is first 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. Diamine concentration is 0.3
If it is less than 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, the diamine concentration is 1.5 mol/I? If it exceeds this, it becomes difficult to achieve uniform stirring and is not practical.
Next, an aliphatic monocarboxylic acid halide and/or an aromatic monocarboxylic acid halide (hereinafter abbreviated as acid halide C) is added to the amide solvent in which the diamine is dissolved.

Acid halides act as viscosity stabilizers by reacting with diamines in amide solvents to form stable compounds. The amount of acid halide used is 0.2 to 1.0 mol% based on the diamine.
It is necessary to be within the range of . 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, variation in the degree of polymerization between batches will be reduced, but only a polymer with a low degree of polymerization will be obtained. Diamine obtained as above,
In the diamine solution consisting of an acid halide and an amide solvent, the acid chloride may be replaced by a non-reactive substituent such as halogen 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 the aliphatic monocarboxylic 9-acid halide or aromatic monocarboxylic acid halide used in the present invention include acetyl chloride, trifluoroacetyl chloride, trimethylacetyl chloride, benzoyl chloride, α- or β-naphthoic acid chloride, and the like.

These monocarboxylic acid halides react with, for example, diamines as shown in the following formula to become stable compounds in amide solvents. Polymerization is carried out by adding loride.

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. If the amount of acid chloride is A weight % or less of the total amount of acid chloride to be added during polymerization, that is, the equimolar amount of acid chloride to the diamine used,
It can be added to the reaction system all at once. Here, A means
These values are obtained from equations (1), (2), and (3) above depending on the temperature of the reaction system and the aromatic diamine concentration at the start of the polymerization reaction, but if the value of A is 100 or more, the polymerization The total amount of acid chloride to be added, i.e. 100% by weight
This means that it can be added to the reaction system all at once. A weight%
When adding acid chloride to the reaction system all at once,
It 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 amount of acid chloride added at once to the reaction system. The temperature of the reaction system at the start (t
) and the value of (50-t)/m obtained from the diamine concentration ω. In the figure, the ○ marks indicate that when polymerization was carried out under the conditions (corresponding to Examples 1 to 4 and 6 to 9 described later), there was little variation in the degree of polymerization from batch to batch, whereas the × marks indicate that the degree of polymerization varied from batch to batch. The case where the polymerization was carried out (corresponding to Comparative Examples 3 to 7 described later) indicates that the degree of polymerization varied greatly from batch to batch. From FIG. 1, in order to reduce variation in the degree of polymerization from batch to batch, the initial addition ratio (wt%) of acid chloride should be set to 0.00000% depending on the temperature (t) of the reaction system at the start of polymerization and the concentration of diamine. The value expressed as 89(50-t)/m (
4) It is clear that the following must be true.

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 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, variations in the degree of polymerization from batch to batch can be reduced when producing aromatic polyamide from diamine and acid chloride.

The aromatic polyamide produced by the method of the present invention is
Since there is little variation in the degree of polymerization from batch to batch, there are no problems in molding, and the excellent properties can be fully demonstrated as molded products such as films, fibers, and papers of uniform quality. EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples.

In the example, the logarithmic viscosity (ηInh) was used as a guideline for the degree of polymerization, but this is a solution of a polymer dissolved in 96% sulfuric acid at a concentration of C = 0.5 (0.57 polymer/100 m of sulfuric acid). was measured at 25° C. using an Ostwald viscometer in a conventional manner, and was obtained using the following formula: (ηRel: relative viscosity) Example 1 A 250-meter tank equipped with a high-speed rotating stirring blade and capable of nitrogen purging.
13.0 y of metaphenylene diamine and 100 ml of thoroughly dried dimethylacetamide were placed in a flask No. 1 and dissolved therein (diamine concentration 1.20 mol/l).

Then, 0.0687 of benzoyl chloride (0.40 mol % to diamine) was added and reacted, and then cooled to 2°C. In this case, the value of A in equation (1) was 35.6. Isophthalic acid dichloride 8 is added to this diamine solution.
．． 447 (corresponding to 34.4% by weight of the amount to be added).
) was added all at once, and then 16.0y was added over 5 minutes. Isophthalic acid chloride was used in the form of approximately 5 mesh granules. Stirring was continued for an additional hour after the addition of isophthalic acid chloride. The obtained reaction solution was poured into water, the polymer was precipitated and pulverized, the solvent was sufficiently extracted with hot water, the mixture was washed, and then dried under reduced pressure to obtain a polymer. Repeat polymerization 5 times,
The logarithmic viscosity of the obtained polymer was measured and found to be 1.56.
~1.62, and the standard deviation was 0.019. Comparative Example 1 Polymerization was repeated 10 times in the same manner as in Example 1, except that the entire amount of isophthalic acid chloride was added in 3 minutes.

The logarithmic viscosity of the obtained polymer was measured and found to be 1.08.
It was low at ~1.40 and the standard deviation was large at 0.104. Comparative Example 2 Polymerization was carried out five times in the same manner as in Example 1, except that benzoyl chloride was not used.

The logarithmic viscosity of the obtained polymer was measured and found to be 1.75.
~2.85, and the standard deviation was very large at 0.308. Example 2 Paraphenylenediamine 2.277 was dissolved in 30TIII mixed solvent of hexamethylphosphoramide/N-methyl-2-pyrrolidone (1/1 volume ratio) (diamine concentration 0.70 mol/e) Later, acetyl chloride 0,0
357 (0.21 mole % to diamine) was added, allowed to react, and cooled to 10'C.

In this case, the value of A in equation (1) was 50.9.
Add terephnoyl dichloride 2.007 (
This corresponds to 47% by weight of the amount to be added. ) was added all at once, and the remaining 2.26y was added over 5 minutes. Terephthalyl chloride was used in powder form, and stirring was continued for an additional 30 minutes after addition. The resulting reaction solution turned into a powdery gel approximately 5 minutes after the addition of terephthalic acid chloride. After the reaction is complete,
A polymer was obtained in the same manner as in Example 1. Polymerization was repeated 5 times in the same manner, and the logarithmic viscosity of the obtained polymer was measured to be 5.47 to 5.55, with a standard deviation of 0.02.
It was 1. Example 3 N-methyl-2-pyrrolidone 41, metaphenylenediamine 346.0y and paraphenylenediamine 86.0y.
57 was dissolved (diamine concentration 1.00 mol/I?)
.

Then, 2.81 g of benzoyl chloride was added to this diamine solution.
After adding and reacting V (0.50 mol % to diamine), the mixture was cooled to -5°C. In this case, A in equation (1)
The value was 49.0. Molten isophthalic acid chloride 3207 (the amount to be added of 39
．． This corresponds to 4% by weight. ) was added all at once, and the remaining 49
2.17 was added in about 20 minutes.

After the addition of isophthalic acid chloride, stirring was continued for an additional hour, and then a polymer was obtained in the same manner as in Example 1. Polymerization was repeated 5 times, and the logarithmic viscosity of the obtained polymer was measured to be 1.53 to 1.62, with a standard deviation of 0.026.
It was hot. Example 4 In a 250 ml flask equipped with a stirring blade that rotates at high speed and whose viscosity can be detected by a torque meter, 13.0 y of metaphenylenediamine and 100 ml of dimethylacetamide that had been thoroughly dehydrated and dried were charged and dissolved ( After the diamine concentration was 1.20 mol/f?.), 0.0657 mol of benzoyl chloride (0.38 mol % vs. diamine) was added and reacted, and then the mixture was cooled to 5°C.

In this case, the value of A in equation (1) was 33.4.
Add 7.00y of inphthalic acid chloride to this diamine solution (
This corresponds to 28.6% by weight of the amount to be added. ) was added over 8 seconds, followed by 17.07 g of isophthalic chloride over 10 minutes.

Further, while maintaining the temperature of the reaction solution at 40° C., isophthalic acid chloride was added little by little until the value on the torque meter no longer increased. After continued stirring for 1 hour, a polymer was obtained in the same manner as in Example 1. Polymerization was repeated five times in the same manner.

The total amount of isophthalic acid chloride used was 24.68 ~
The range is 25.43y, which is 0.43y of the amount to be added.
The amount corresponded to an excess of 98 to 4.1%. The logarithmic viscosity of the obtained polymer was measured and was 1.48 to 1.54.
The standard deviation was 0.01. Example
5 31.27 m of metaphenylene diamine, 7.87 m of paraphenylene diamine, and 300 m of N-methylpyrrolidone were placed in 11 reaction vessels equipped with a wattmeter capable of measuring the power consumption of the motor that drives the stirring blades.
1 and dissolved the diamine (diamine concentration 1.
20 mol/l), then acetyl chloride 0.127(0
．． 42 mol % of diamine) was added and reacted, and the mixture was cooled to 3°C.

In this case, the value of A in equation (1) was 34.9.
Isofunolic acid chloride 70.0f dissolved in this solution
was added over 10 minutes, and isophthalic acid chloride was added little by little until the wattmeter value no longer increased. Polymerization was repeated five times in the same manner. The total amount of isophthalic acid chloride used was 73.41 to 74.127
This ranges from 0.3 to 1.2% of the amount to be added.
The amount was equivalent to excess. When the logarithmic viscosity of the obtained polymer was measured, it was in the range of 1.88 to 1.92,
The standard deviation was 0.01. Examples 6 to 9 250 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. 31 was used only in Example 9), and dissolved, and then benzoyl chloride in the amount shown in Table 1 was charged. was added, reacted, and then cooled to the initial temperature shown in Table 1.

Approximately 5 meshes of granular isofusioyl dichloride were added to this diamine solution in the amount shown as the initial addition amount in Table 1, and the remaining amount to be added was added over the time shown in Table 1. A polymer was obtained in the same manner as in 1. Polymerization was repeated five times in the same manner. The logarithmic viscosity and standard deviation of the obtained polymer were as shown in Table 1. In addition, 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 fisofumeric acid dichloride was changed to A in formula (1)
Polymers were obtained in the same manner as in Examples 6 to 9, 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 6 to 9, 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-TYm).

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, aliphatic monocarboxylic acid halide and/or aromatic monocarboxylic acid dichloride 0.2 to 1.0 mol % of carboxylic acid halide is added to the aromatic diamine, reacted with the aromatic diamine, and then A weight % of the total amount of aromatic dicarboxylic acid dichloride to be added into the reaction system. [However, A is the following (1), (2) and (3)
A method for producing an aromatic polyamide, which comprises adding the following amount of aromatic dicarboxylic acid dichloride, and then adding the remaining aromatic dicarboxylic acid dichloride over a period of 5 minutes or more. 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 (mol/l) at the start of the reaction. 2. When producing aromatic polyamide by adding aromatic dicarboxylic acid dichloride to a solution of aromatic diamine dissolved in N-substituted amide polar solvent, aliphatic monocarboxylic acid halide and/or aromatic monocarboxylic acid halide are added to aromatic dicarboxylic acid dichloride. A weight % of the total amount of aromatic dicarboxylic acid dichloride to be added to the diamine in an amount of 0.2 to 1.0 mol %, reacted with the aromatic diamine, and then added into the reaction system [However, A is the following (1), (2) and (3) of
[value expressed by the formula]], then the remaining aromatic dicarboxylic acid dichloride was added over 5 minutes or more, and the aromatic dicarboxylic acid dichloride was further added until no increase in the viscosity of the reaction system was substantially observed. A method for producing aromatic polyamide, which comprises additionally adding dicarboxylic acid dichloride. 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 (mol/l) at the start of the reaction.