JPS5913532B2 - Houkozoku Polyamide No. Seizou Hohou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing aromatic polyamide, and its purpose is to control the polymerization process for each batch when producing aromatic polyamide from aromatic diamine and aromatic dicarboxylic acid dichloride. It is an object of the present invention to provide a manufacturing method that can reduce fluctuations in temperature.

Aromatic polyamides have useful applications in films, fibers, and paper due to their excellent heat resistance and mechanical properties. However, even when attempting to obtain aromatic polyamides by reacting aromatic diamines and aromatic 5-group dicarboxylic acids, it is difficult to obtain polymers with a high degree of polymerization that can be molded into films, fibers, and paper due to low reactivity. 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 have sufficient mechanical properties as a molded article. Therefore, aromatic dicarboxylic acid dihalides, especially aromatic dicarboxylic acid chlorides, which have higher activity are generally used, but since the reaction between aromatic diamines and aromatic dicarboxylic acid chlorides occurs rapidly, local reactions may occur. The progress of the process and the accompanying heat generation promotes the side reaction between the aromatic dicarboxylic acid chloride and the amide solvent.
This causes 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 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 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 reacting an aromatic diamine with a specific viscosity stabilizer in an N-substituted amide polar solvent, aromatic dicarboxylic acid dichloride was Variations in the degree of polymerization between batches can be reduced by adding at a certain rate and polymerizing, and after adding a predetermined amount of aromatic dicarboxylic acid dichloride, until no increase in the viscosity of the reaction system is observed. It was discovered that by successively adding aromatic dicarboxylic acid chloride, the variation in the degree of polymerization between batches could be further reduced, and the present invention was achieved.

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 isocyanate and/or aromatic isocyanate is A weight % of the total amount of aromatic dicarboxylic acid dichloride to be added to the group diamine and reacted with the aromatic diamine, and then added to the reaction system [However, A is The following amounts are expressed by the following formulas (1), (2), and (3)], and then the remaining aromatic dicarboxylic acid dichloride is added for 5 minutes or more. Method for producing group polyamide and (2) aromatic diamine in an N-substituted amide polar solvent (hereinafter abbreviated as amide solvent).

) When producing an aromatic polyamide by adding an aromatic dicarboxylic acid dichloride to a solution dissolved in a diamine, an aliphatic isocyanate and/or an aromatic isocyanate is added in an amount of 0.2 to 1.0 mol% based on the aromatic diamine. A% by weight of the total amount of aromatic dicarboxylic acid dichloride to be reacted with the aromatic diamine (hereinafter abbreviated as diamine) and then added to the reaction system [However, A is the following (1)
and the value expressed by formula (2)] is added in the following amount, and then the remaining aromatic dicarboxylic acid dichloride is added over a period of 5 minutes or more, until substantially no increase in the viscosity of the reaction system is observed. This is a method for producing aromatic polyamide, which is characterized in that aromatic dicarboxylic acid dichloride (hereinafter abbreviated as acid chloride) is additionally added until Tatashi,
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 1) The amide solvent used in the present invention is N,N dimethylacetamide, N,N-diethylacetamide, N,N
-dimethylpropionamide, N,N-diethylpropionamide, tetramethylurea, tetraethylurea, N-methyl-2SS pyrrolidone, N-methyl-2-piperidone, SS hexamethylphosphoramide, hexaethylphosphoramide, etc. Used alone or in combination.

Examples of the aliphatic isocyanate or aromatic isocyanate used in the present invention include ethyl isocyanate, phenyl isocyanate, and n-tolyl isocyanate.

These isocyanates react with, for example, diamines as shown in the following formula to become stable compounds in amide solvents.
H2N-R1-NH2+R5-NCO→ H2N-R1-NHCONH-R5 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). Alternatively, it refers to a compound represented by formula (6).

CLCO-R4-X2-R4-COCL (6) in the above formula,
Rl, R2, R3 and R4 represent aromatic rings and may be the same group or different groups.

Such aromatic rings include phenylene, naphthalene, bifninyl, etc., and one or more hydrogen atoms in the aromatic ring may be replaced with 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. To produce an aromatic polyamide by the method of the present invention, first a diamine is dissolved in an amide solvent.

In this case, the diamine concentration is 0.3 mol/l or more, 1.5
It is necessary to adjust the amount to be less than mol/l. 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 cause of variation in the degree of polymerization of the polymer. On the other hand, if the diamine concentration exceeds 1.5 mol/2, it becomes difficult to achieve uniform stirring, which is not practical. Then, an aliphatic isocyanate and/or an aromatic isocyanate (hereinafter abbreviated as isocyanate) is added to the amide solvent in which the diamine is dissolved. Isocyanates act as viscosity stabilizers by reacting with diamines in amide solvents to form stable compounds. The amount of isocyanate used must be in the range of 0.2 to 1.0 mol % based on the diamine. 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. Polymerization is carried out by adding acid chloride to the diamine solution containing the diamine, isocyanate, and amide solvent obtained as described above.

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 aromatic diamine concentration, but if the value of A is 100 or more In the case of , the total amount of acid tallolide to be added during polymerization, that is, 100% by weight? This means that it can be added to the reaction system all 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)/m determined from the temperature (t) of the reaction system and the concentration (m) of the diamine at the time. In the figure, the ○ marks indicate that when polymerization is carried out under those conditions (corresponding to Examples 1 to 8 described below), there is little variation in the degree of polymerization from batch to batch, whereas the × marks indicate that polymerization is carried out under those conditions. The case (corresponding to Comparative Examples 3 to 7 described later) 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 (wt%) of acid chloride should be adjusted to 0 depending on the temperature (t) of the reaction system at the start of polymerization and the concentration of diamine.
．． It is clear that it must be less than or equal to the value A expressed as 89(50-t)/m.

After adding the amount of A weight % or less, the remaining acid chloride must be added over a period of 5 minutes or more.

Adding in a shorter period of time is also not suitable because it is difficult to control the degree of polymerization and 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, 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 addition, in the example, the logarithmic viscosity (η1nh) was used as a guideline for the degree of polymerization, but this is 96% by weight? A solution of a polymer dissolved in sulfuric acid at a concentration of C = 0.5 (0.59 polymer/100 rne of sulfuric acid) was measured at 25°C using an Ostwald viscometer in the usual manner, and was obtained using the following formula. be.

(ηRel: relative viscosity) Example 1 250 m equipped with high-speed rotating stirring blades and capable of nitrogen replacement
6.5 f1 of paraphenylene diamine and 100 g of a thoroughly dried mixed solvent of hexamethylphosphoramide/N-methyl-2-pyrrolidone (1/1 volume ratio) were placed in flask e.
me was prepared and diamine was dissolved (diamine concentration 0.6
0 mol/l).

Then, phenyl isocyanate 0.0439 (0.6
0 mol % of diamine) was added, reacted, and then cooled to 5°C. In this case, the AO) value shown in equation (1) is 66.
It was 8. To this diamine solution, 3.0f1 of terephthalic acid chloride (corresponding to 24.6% by weight of the amount to be added) was added at once, and then the remaining 9.29ml was added over 5 minutes. Terephthalic acid chloride is used in bulk form,
Stirring was continued for an additional 30 minutes after the addition was complete. After the addition of terephthalyl chloride, the reaction solution changed from a viscous solution to a powdery gel. Grind this in water, thoroughly extract the solvent with hot water,
After washing, the polymer was dried under reduced pressure to obtain a polymer. Polymerization was repeated five times in the same manner, and the logarithmic viscosity of the obtained polymer was measured to be 4.48 to 4.55, with a standard deviation of 0.023.

Comparative Example 1 Polymerization was repeated 5 times in the same manner as in Example 1 except that phenyl isocyanate was not used, and the logarithmic viscosity of the obtained polymer was measured to be 7.98 to 12.81, with a standard deviation of 1 It was large at .78.

Comparative Example 2 Polymerization was carried out five times in the same manner as in Example 1, except that the entire amount of terephthalic acid chloride was added at once.

The logarithmic viscosity of the obtained polymer was measured and found to be 2.37.
~4.18, and the standard deviation was as large as 0.34.
Example 2 Metaphenylenediamine 1 in dimethylacetamide 11
08.19 and 4,4'-diaminodiphenyl ether 40.09. (Concentration of diamine 1.20 mol/2) Phenyl isocyanate 0.51 f1 is added to this solution.
(0.36 mol% to diamine) was added and reacted, and 10
Cooled to ℃.

In this case, the value of A in equation (1) was 29.7. To this diamine solution was added 70.09 g of molten isophthalic acid dichloride (corresponding to 28.7% by weight of the amount to be added) under high speed stirring in about 30 seconds, and then the remaining 173 g.
．． 69 was added over 7 minutes. Thereafter, a polymer was obtained in the same manner as in Example 1. Polymerization was repeated five times, and the logarithmic viscosity of the obtained polymer was measured to be 1.49 to 1.57, with a standard deviation of 0.031. Example 3 Metaphenylenediamine 6.59 and sufficient 250 ml of metaphenylenediamine were added to a 250-me flask equipped with a stirring blade that rotated at high speed and whose viscosity could be detected using a torque meter. N that was water-dried
- 100 me of methylpyrrolidone was charged to dissolve the diamine (concentration of diamine: 0.60 mol/l).

Then phenyl isocyanate 0.0409 (0.56
mol % of diamine) was added and then cooled to 5°C.
In this case, the value of A in equation (1) was 66.8.
Add terephthalic acid chloride 3.009 (
This corresponds to 24.5% by weight of the amount to be added. ) was added for 10 seconds, then 89 was added over 5 minutes,
Subsequently, while maintaining the temperature of the reaction solution at 40° C., terephthalic 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 5 times in the same manner. The total amount of terephthalic acid chloride used ranged from 12.31 to 12.849, which was an amount in excess of 0.7 to 5.1% over the amount to be added. When the logarithmic viscosity of the polymer thus obtained was measured, it was in the range of 1.76 to 1.82.
The standard deviation was 0.01. Example 4 Dimethylacetamide 1! Metaphenylenediamine 1
40.69 (concentration of diamine 1.30 mol/
l) Ethyl isocyanate 0.37f! (0.40 mol % to diamine) was added and reacted, and then cooled to 10°C.

In this case, the value of A in equation (1) was 27.4.
Isophthalic acid chloride 60.0f1 is added to this diamine solution.
(corresponding to 22.7% by weight of the amount to be added) was added over 8 seconds, followed by 2009 over 15 minutes.
Further, while maintaining the temperature of the reaction solution at 40° C., isophthalic acid chloride was added little by little until no increase in the viscosity of the reaction solution was observed. Thereafter, a polymer was obtained in the same manner as in Example 1. Polymerization was carried out in 5 batches, and the total amount of isophthalic acid chloride added was 264.9 to 268.3.
9, which corresponded to a 0.3 to 1.6% excess of the amount to be added. Moreover, the logarithmic viscosity of the obtained polymer is in the range of 1.56 to 1.62, and the standard deviation is 0.
It was 01. Examples 5 to 8 A 250me flask equipped with a stirring blade that rotates at high speed and capable of nitrogen substitution (however,
Only Example 8 used 31 flasks), metaphenylenediamine and N-methyl-2-pyrrolidone were added in Table 1.
After charging and dissolving the amount shown in Table 1, the amount of funinyl isocyanate shown in Table 1 was added, reacted, and then cooled to the initial temperature shown in Table 1.

About 5 meshes of granular isophthalic acid 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. Polymerization was repeated 5 times in the same manner. The logarithmic viscosity and standard deviation of the obtained polymer were as shown in Table 1. Furthermore, Table 1
The initial addition ratio is the ratio of the initial addition amount to the amount of isophthalic acid dichloride to be added. Comparative Example 3 - Initial addition ratio of fisophthalic acid dichloride was changed to A in 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 that of Examples 5 to 8, and the 5 times V-1. −? The variation in polymerization was large.

[Brief explanation of drawings]

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

Claims (1)

[Scope of 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 isocyanate and/or aromatic isocyanate are converted into aromatic 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 value expressed by the following formulas (1), (2) and (3)] and then the remaining aromatic dicarboxylic acid dichloride is added over a period of 5 minutes or more. A method for producing 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, aliphatic isocyanate and /or 0.2 to 1.0 mol% of aromatic isocyanate is added to the aromatic diamine and reacted with the aromatic diamine, and then A of the total amount of aromatic dicarboxylic acid dichloride to be added into the reaction system. Weight% [However, A
are the values expressed by the following formulas (1), (2), and (3)], then the remaining aromatic dicarboxylic acid dichloride was added over a period of 5 minutes or more, and the reaction system 1. A method for producing an aromatic polyamide, which comprises further adding aromatic dicarboxylic acid dichloride until substantially no increase in viscosity is observed. A=0.89(50-t)/m(1)0.3≦m≦1.
5(2) t<50(3) Where, 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)