JPH01284527A - Production of poly(p-phenyleneterephthalamide) - Google Patents

Abstract

PURPOSE:To make it possible to improve the stability of a reaction, the degree of polymerization of a poly(p-phenyleneterephthalamide), etc., by reacting p- phenylenediamine with terephthaloyl chloride in the presence of anhydrous LiCl in N-methyl-2-pyrrolidone under specified conditions. CONSTITUTION:The reaction of p-phenylenediamine (a) with terephtnaloyl chloride (b) in an amount substantially equimolar to that of component (a) is started in the presence of anhydrous LiCl (c) in N-methyl-2-pyrrolidone (d) of a purity >=99.9% and a water content <=100ppm under conditions satisfying formulas I-IV (wherein MC is the molar concentration of component (b) with respect to component (d), LC is the molar concentration of component (c), and T is the initial polymerization temperature), and the reaction is continued at 10-100 deg.C to obtain poly(p-phenyleneterephthalamide) of an inherent viscosity >=6.0.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing polyparaphenylene terephthalamide. More specifically, the present invention relates to a production method capable of stably and easily supplying polyparaphenylene terephthalamide with a high degree of polymerization.

[Conventional technology]

Polyparaphenylene terephthalamide has excellent heat resistance, chemical resistance, and mechanical properties, and is useful for fibers, films,
It is extremely useful as a fibrid and is one of the polymers that has received particular attention in recent years.

Polyparaphenylene terephthalamide is made mainly from aromatic diamine and aromatic dicarboxylic acid halide.
It is manufactured by low-temperature solution polymerization in a solvent containing an inorganic salt.

For example, according to Japanese Patent Publication No. 60-48537, NM
According to Japanese Patent Publication No. 60-55538, NMP is subjected to a polymerization reaction in a solvent containing 5% by weight or more of calcium chloride based on the solvent. A method of carrying out a polymerization reaction in a solvent containing at least 5% by weight of calcium chloride has been disclosed.

Generally, as a method for improving the dissolving power of an organic solvent for polyparaphenylene terephthalamide, a method is known in which a metal halide salt of Group 1 and/or Group Ⅰ of the periodic table is added to the solvent. ing.

[Problem that the invention seeks to solve]

In the method using calcium chloride, it is essential to increase the concentration of the inorganic salt calcium chloride in order to obtain polyparaphenylene terephthalamide with a high degree of polymerization. However, when calcium chloride, which is poorly soluble, is concentrated at a high concentration, calcium chloride may remain undissolved or take a long time to dissolve, resulting in clogging in the polymerization equipment and unevenness in the degree of polymerization. may occur. Furthermore, when the concentration of calcium chloride is reduced, the dissolving power of the solvent system decreases, making it impossible to produce high-polymerization degree polyvalent phenylene terephthalamide F at a high yield. Furthermore, as mentioned above, although polymerization methods using other halogenated compounds have been disclosed, by taking advantage of the inherent properties of polyparaphenylene terephthalamide, a sufficient degree of polymerization has been achieved that allows it to be practically used as a molded product. No examples are known yet.

c. Means for Solving Problems] The present inventors focused on anhydrous LiCβ as a metal salt used with an organic solvent, and as a result of intensive studies on its characteristic behavior, , monomer (PDA and TPC) concentration, anhydrous Li
Cj! ? The present invention was achieved by discovering that polyparaphenylene terephthalamide with a high degree of polymerization can be stably produced in a very specific manner when the degree of polymerization and the polymerization reaction initiation temperature are all controlled under specific conditions. be.

That is, the present invention provides N-methyl-2-pyrrolidone (hereinafter referred to as LiCff) containing anhydrous lithium chloride (hereinafter referred to as LiCff).
In producing polyparaphenylene terephthalamide by the reaction of substantially equimolar amounts of paraphenylene diamine (hereinafter referred to as PDA) and terephthalic acid dichloride (hereinafter referred to as TPO) in NMP), P i) The molar concentrations of A and TPC relative to NMP are MC, anhydrous LiCj! When the molar concentration of LC1 and the polymerization reaction initiation temperature are T, they are MC≦0.5 mo 12 / e M'C≦LC≦MCx 1.3 and LC≦0.52
mo It/j! This is a method for producing polyparaphenylene terephthalamide having an logarithmic viscosity of 5.0 or more by carrying out the polymerization reaction under conditions satisfying -10°C≦T≦5°C.

The purity of NMP used in the present invention needs to be 99.9% or higher. Preferably, it is 99.9'9% or more. If the amount of impurity in NMP increases, it becomes a cause of interfering with the polymerization reaction, making it impossible to obtain a polymer with a high degree of gravity. Further, the water content of NMP needs to be 100 pp'm or less. This is because, as mentioned above, this may hinder the polymerization reaction or cause unevenness in the degree of polymerization of the resulting polymer.

LiCI used to increase the dissolving power of the NMP
The purity of T must be 99.0% or higher. Preferably it is 99.5% or more.

If the purity of LiCIt is less than 99.0%, the solvent NMP may have insufficient dissolving power, or impurities in LiCIt may interfere with the polymerization reaction. A polymer with a certain degree of polymerization cannot be obtained. In addition, LiC1 has good solubility in NMP compared to calcium chloride, so there is no particular problem even if it is in relatively large particles, but in order to shorten the dissolution time, it is necessary to pass through a 5 sieve sieve. The size of is preferable.

When producing polyparaphenylene terephthalamide by the method of the present invention, it is necessary to prepare a solution in which LiCβ that satisfies the above conditions is dissolved in NMP that also satisfies the conditions. The amount of LiC1 added is 1.0 times or more and 1.3 times or less than MC, and 0.52 mo (1/ (!
It is as follows. I-i Addition amount of C12 is 1 to MC
．． If it is less than 0 times, polymerization of the resulting polymer may be insufficient or precipitation of the polymer may occur during the polymerization reaction.

Moreover, the same thing occurs even if the ratio exceeds 1.3 times. Furthermore, although the cause is unknown, 0.52 mo j! / 1 or more, regardless of MC, a polymer with a high degree of polymerization cannot be obtained because the polymer precipitates after the start of the polymerization reaction, so 0.52 moj! It is necessary to make the addition amount less than /β.

In the polymerization reaction of the present invention, mixing of 1,000 yen can be carried out as follows. That is, in the solvent NMP, L
A solution was prepared by adding PDA to the solution containing iC(l, and after adjusting the starting temperature, T"
The polymerization reaction may be carried out by adding and mixing PC.

MC in the present invention is 0.5 moI with respect to NMP!
, //must be less than or equal to 2. When L i C1 is used, it is very characteristic that if it exceeds 0.5 mop/A, polymer precipitation will be extremely rapid after the start of the polymerization reaction, making it impossible to obtain a polymer with a high degree of polymerization.

The polymerization initiation temperature (T) needs to be set at -10°C to 5°C. If T is less than 10°C, the polymerization reaction of the resulting polymer will not proceed sufficiently, and if I exceeds 5°C, polymer precipitation will occur during the polymerization reaction, and in either case, the polymer with a high degree of polymerization will can't get it. The temperature of the cooling bath for adjusting the polymerization initiation temperature (T) is -5
The refrigerant used is brine, methanol, ethanol, ice water, calcium chloride, etc., but any refrigerant may be used as long as it satisfies the above temperature.

The temperature after the start of the reaction is preferably selected to be 10 to 100°C, more preferably 30 to 80°C. If the temperature after the start of the reaction exceeds 80°C, decomposition of the polymer often occurs during the polymerization reaction, which is not suitable for obtaining a polymer with a high degree of polymerization.

After the polymerization starts, the polymerization reaction system gradually increases in viscosity, changes from a paste-like state to a gel-like state, and becomes powder-like or granular-like by further kneading. Examples of polymerization reaction equipment that can add sufficient stirring and mixing to such a polymerization reaction system include an eye-screw or twin-screw extruder,
Examples include a continuous Nigoo mixer, a reciprocating rotary reactor, and a vertical stirring tank. In the laboratory, a small test kneader or a small vertical stirring tank is conveniently used. In such a device, the polymerization reaction product is processed into powder form or
A polymer with a high degree of polymerization can be obtained by kneading until it becomes granular.

The degree of polymerization of the polymer in the present invention is at least 5.0.
As mentioned above, it is necessary to preferably have a logarithmic viscosity of 6.0 or more. If the logarithmic viscosity is less than 5.0, desired mechanical strength cannot be obtained when molded into fibers, films, etc.

After the polymerization reaction is completed, the powdered or granular polymerization reaction product is washed as it is with water, aqueous alkaline solution, acetone, methanol, chloroform, etc., and then dried and isolated as a polymer. The obtained polymer can be molded into fibers, films, fibrin V, etc. using a dope prepared by redissolving it in sulfuric acid by a wet molding method or a so-called dry diesotho-wet molding method.

These molded products are widely used for both industrial materials and clothing, such as rubber reinforcing materials for tires, healds, air punctures, etc., resin reinforcing materials, heat-resistant clothing, and heat-resistant films. It is used as heat-resistant paper, hollow fiber, etc., and its characteristics such as high cohesion, high Young's modulus, heat resistance, and flame retardance are fully exhibited.

〔Example〕

Examples of the present invention are shown below, and the logarithmic viscosity (η1nh) shown in the examples as a guideline for the degree of polymerization is as follows: A solution prepared by melting the above was measured at 35°C using a conventional method.

Examples 1 to 5 NMP purified by distillation was added to a dried stainless steel separable flask with an internal volume of about 2000 ml at 1400 ml.
Powdered LiCj!ml, and further prepare powdered LiCj to the concentration -I O-- as shown in Table 1. and PDA were charged and dissolved at room temperature. Next, the temperature of the solution in the stainless steel separable flask was adjusted to -20°C to 0°C.
After adjusting with dry ice methanol at ℃, the amount of TPO powder shown in Table 1 was added and vigorously stirred. TPC was rapidly dissolved, and the polymerization reaction system gradually increased in viscosity and became gel-like, but it was continued to be vigorously stirred and kneaded until the polymerization reaction product became powder-like. The powdered polymerization reaction product is taken out, washed with water, and dried to isolate the polymer.
Logarithmic viscosity (η1nh) was measured. The results are shown in Table 1.

Comparative Examples 1 to 5 In the same manner as in Examples 1 to 5, polymerization was carried out when calcium chloride was charged alone and when the molar concentration of LiCβ added to MC (LC) was outside the range of the present invention. went. The results are shown in Table 1.

〔Effect of the invention〕

According to the method of the present invention, in a solution of NMP containing LiCβ, and at a lower concentration of LiCl1 than in the prior art,
Polyparaphenylene terephthalamide with a high degree of polymerization can be produced. Furthermore, since LiCj+ is extremely easily dissolved in NMP, it is easy to handle industrially and the degree of polymerization is stable because there is no residual LiCl1 solution. A polymer with

Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] N containing anhydrous lithium chloride (hereinafter referred to as LiCl)
- In methyl-2-pyrrolidone (hereinafter referred to as NMP), substantially equimolar amounts of para-phenylenediamine (hereinafter referred to as PDA) and terephthalic acid dichloride (hereinafter referred to as TP)
In producing polyparaphenylene terephthalamide by reaction with NM of PDA and TPC
When the molar concentration of P is MC, the molar concentration of anhydrous LiCl is LC, and the polymerization reaction initiation concentration is T, they are MC≦
0.5 mol/l MC≦LC≦MC×1.3 and LC≦0.52 mol
/l-10°C≦T≦5°C, the polymerization reaction is carried out under conditions satisfying Production method