BE851965A - PROCESS FOR OBTAINING POLY-P-PHENYLENETERAPHTALAMIDE OR ITS COPOLYMERS - Google Patents

Description

       

   <EMI ID = 1.1>

  
Methods of obtaining the

  
 <EMI ID = 2.1>

  
namely aromatic polyamides used for the preparation of thermostable fibers, very resistant and having high characteristics.

  
Particular characteristics of the polyamides indicated are their high thermostability, their high melting temperatures, their resistance to the action of the majority of organic solvents.

  
 <EMI ID = 3.1>

  
de and its copolymers have a mechanical strength of
140 to 225 gf / tex at an elongation of 5 to 2,, an elongation modulus of 6000 to 14000 kgf / mm2 and a density of 1.43 to 1.46 g / cm3.

  
These fibers are hardly combustible, chemically stable and have good fatigue resistance and long lasting mechanical strength; They can be used as tire cord as well as in the manufacture of reinforced plastics for various purposes.

  
There are a number of processes for obtaining poly-p-phenyleneterephthalamide and its copolymers, among which the most preferred, from the point of view of obtaining a high molecular weight polymer, are the processes based on the polycondensation reaction. p-phenylenediamine with terephthalic acid dichloranhydride being carried out in solution at a temperature below 100 [deg.] C. After obtaining the copolymers, a portion (5 to 50 mol.) Of p-phenylenediamine and / or terephthalic acid dichloroanhydride is replaced by another aromatic monomer (respectively by diamine or dichloroanhydride).

  
A common feature of all these processes is the fact that in these processes p-phenylenediamine is used as one of the monomers which, in the form of a solution in any organic solvent, reacts with terephthalic acid dichloroanhydride. solid or molten.

  
 <EMI ID = 4.1>

  
derives from the fact that it has, as the starting monomer for obtaining poly-p-phenyleneterephthalanide, the ability to oxidize easily, both during its production.

  
 <EMI ID = 5.1>

  
from p-phenylenediamine requires, on the one hand, the production of the meticulously purified p-phenylenediamine or its purification directly before the synthesis of the polymer and on the other hand, to carry out the synthesis under conditions excluding the oxidation of the polymer. diamine, particularly at the stage of preparation or use of its solutions.

  
The known processes for obtaining poly-p-phenyleneterephthalamide differ from each other essentially in the type of organic solvent used. In these processes it is proposed to use as solvents the following:

  
hexamethylphosphoramide; mixtures of hexamethylphosphoramide and other amide solvents; solutions of alkali and alkaline earth metal salts (LiCl, LINO 3 LiSCN, KSCN, CaCl2, MgClp, etc.) in various linear or cyclic N-alkyl-substituted amides of acids (dinethylacetamide, tetramethylurea, N-methylpyrrolidone, etc. :) , so-called amido-saline solvents.

  
When hexamethylphosphoramide was used as the solvent, poly-p-phenylene- first obtained.

  
 <EMI ID = 6.1>

  
was unsuitable for the preparation of very resistant fibers and it was only after the improvement of the process (meticulous mixing of the massa) that we succeeded in obtaining a

  
 <EMI ID = 7.1>

  
imposed on -The production of very resistant fibers.

  
Poly-p-phenyleneterephthalamide and its high molecular weight copolymers are successfully prepared in mixtures of hexamethylphosphoramide with other amide solvents. In fact, a mixture of hexamethylphosphoramide + N-methylpyrrolidone (2/1 according to

  
 <EMI ID = 8.1>

  
3.80 dl / g.

  
The synthesis of high molecular weight poly-p-phenyleneterephthalamide and its copolymers is carried out with less success in a solution of amidosaline solvents representing a large group of easily accessible solvents and widely used in the synthesis of aromatic polyamides of different structure.

  
In this way, the known processes for obtaining poly-p-phenyleneterephthalamide and its copolymers result in obtaining the high molecular weight product only in the case where hexamethylphosphoramide or its mixtures are used as solvent. with other amide solvents. However, these solvents have the following drawbacks:

  
 <EMI ID = 9.1>

  
targeted;

  
2. hexamethylphosphoramide is one of the solvents with the highest boiling point among amide solvents (Eb = 230 to 232 [deg.] C) which makes it more difficult and

  
 <EMI ID = 10.1>

  
synthesis (distillation for the purpose of drying) and for the subsequent regeneration after the isolation of the targeted products (separation of the targeted products and the precipitant) in comparison with amide solvents with a lower boiling point.

  
The present invention aims to eliminate the indicated drawbacks of the known methods.

  
It has been proposed to modify the conditions of the polycondensation of aromatic diamines with the di-

  
 <EMI ID = 11.1>

  
high molecular weight suitable for manufacturing high strength fibers, as well as simplify technology

  
of the entire process. The solution consists in providing a process for obtaining poly-p-phenyleneterephthalamide or its copolymers by dissolving p-phenylene-

  
 <EMI ID = 12.1> of the diphenyl series in amido-saline solvents consisting of linear or cyclic N-alkyl-substituted amides of acids, and of alkali or alkaline-earth metal salts soluble in the amides indicated in an amount of 1 to 3 moles per mole of diamines to be dissolved, with subsequent introduction into the solutions obtained at a temperature of 0 to 20 [deg.] C of terephthalic acid dichloroanhydride or of a mixture of terephthalic acid dichloranhydride and Aromatic dichloroanhydride of the diphenyl series in amounts equimolar to the diamines, subsequently obtaining a reaction mixture, maintaining the reaction mixture under stirring for 3 to
70 minutes and isolating the targeted product from the mass obtained.

   In accordance with the invention, the tertiary amines are introduced into the reaction mixture before it is maintained in an amount of 2 to 6 moles per mole of starting diamines.

  
The introduction of a tertiary amine in an amido-saline solvent results in the increase of the rate of the polycondensation of the aromatic diamines mentioned.

  
year

  
 <EMI ID = 13.1>

  
In fact, in solvents having an insufficiently high dissolving power with respect to the polymers to be synthesized, such as amido-saline solvents (for example dimethylacetamide + LiCl) with respect to poly-p-phenyleneterephthalamide and to its copolymers, one obtains polymer products with a higher molecular weight than without the introduction of a tertiary amine. In view of the increased rate of the polycondensation reaction and subsequent introduction of a tertiary amine, the requirements on the purity of the starting solvent, in particular on its moisture, are reduced. To obtain the polymer products' with high molecular weight, according to the proposed process, it is admissible to use the solvent having a moisture content

  
 <EMI ID = 14.1>

  
Given that tertiary amines are compounds chemically active vis-à-vis the aforementioned aromatic dichloranhydrides, the order of the introduction of the constituents into the reaction system is a very important condition for obtaining poly-p-phenyleneterephthalamide and of its high molecular weight copolymers. High molecular weight polymer products are obtained when the tertiary amine is introduced into the system directly after loading the dichloroanhydrides. The introduction of the tertiary amine before the loading of the dichloranhydrides does not result in a significant increase in the molecular weight of the polymers

  
to synthesize.

  
For the synthesis of poly-p-phenyleneterephthalamide and its undyed high molecular weight copolymers,

  
 <EMI ID = 15.1>

  
diamine or the solution of p-phenylenediamine and an aromatic diamine of the diphenyl series to employ hydrochloric pphenylenediamine and to dissolve the latter in the presence of tertiary amines in an amount of 2 to 4 moles per mole of hydrochloric p-phenylenediamine.

  
The tertiary amine introduced at the stage of dissolving hydrochloric p-phenylenediamine reacts with the hydrogen chloride forming part of the hydrochloric pphenylenediamine. Thanks to this fact, it is rapidly dissolved with the formation of a free diamine. AT

  
 <EMI ID = 16.1>

  
lution of hydrochloric p-phenylenediamine does not exceed <EMI ID = 17.1>

  
drric is more stable to oxidation than p-phenylenediamine, the latter resulting from the reaction between the indicated salt and the tertiary friend, is sufficiently pure

  
and thanks to rapid dissolution at a non-elevated temperature does not undergo substantial oxidation.

  
After subsequent introduction into the prepared solutions containing the initial aromatic diamines, terephthalic acid dichloroanhydride or terephthalic acid dichloroanhydride and an aromatic dichloride of the diphenyl series as well as from 2 to 6 moles of a tertiary amine per mole of initial diamines, it

  
rapid formation of polymer products takes place

  
high molecular weight similar to those obtained from

  
highly purified p-phenylenediamine under conditions precluding its oxidation (for example, in the case of continuous blowing of the reactor with an inert gas).

  
It is recommended to use as amines

  
 <EMI ID = 18.1>

  
amine, dimethylaniline, quinoline, pyridine, triethylamine, N-methylmorpholine.

  
In order to simplify the technological procedure for isolating the targeted product from the mass obtained, it is advantageous to subject it to granulation, washing with water and drying.

  
In Table I below are given comparative results of the synthesis of poly-p-phenylenetetraphthalamide in amido-saline solvents by the proposed process and by a known process.

  
TABLE 1

  

 <EMI ID = 19.1>


  
The low viscosity of the polymer obtained from hydrochloric p-phenylenediamine without the use of tertiary amines is conditioned by the fact that hydrochloric p-phenylenediamine has a very low solubility in the araido-saline solvents used and therefore the polycondensation reaction takes place. takes place under heterogeneous conditions at a low speed.

  
The comparative results shown show that

  
 <EMI ID = 20.1>

  
phthalamide with a molecular weight appreciably higher than that prepared by the known process.

  
As initial reagents for preparation of

  
 <EMI ID = 21.1>

  
terephthalic acid dichloranhydride and / or, pphenylenediamine is replaced respectively by the di- <EMI ID = 22.1>

  
liqua or diphenyloxide-4,4-dicarboxylic acid) and by aromatic diamines of the diphenyl series (for example, by benzidine, 4,4 -diaminodiphenyloxide, 4,41-

  
 <EMI ID = 23.1>

  
tho-tolidine, orthc-dianisidine).

  
According to the invention, as tertiary amines can be used tertiary amines of different structure, such as tertiary amines alipha-

  
 <EMI ID = 24.1>

  
aromatic res (eg dimethyl or diethylan), fatty aromatic tertiary amines (such as

  
 <EMI ID = 25.1>

  
As amido-saline solvents for the preparation of high molecular weight poly-p-phenyleneterephthalamide and its copolymers, according to the invention, it is possible to use solutions of LiCl, LINO 32 LiBr, LiSCN,

  
 <EMI ID = 26.1>

  
alkali or alkaline earth metals in linear or cyclic N-alkyl substituted amides, for example,

  
 <EMI ID = 27.1>

  
ethylacetamide, tetramethylurea. The concentration of the salt in the solvent should be 1 to 3 moles per mole of aromatic diamines (or aromatic dichloranhydrides).

  
The process in question is preferably carried out as follows.

  
 <EMI ID = 28.1>

  
or alkaline earth or hydrochloric p-phenylenediamine, the indicated salt and a tertiary amine are dissolved with stirring in the amide at a temperature of 20 to 60 [deg.] C for 10 to 60 minutes. The concentration of the diamine solution is 0.1 to 0.4 mole / 1, the amount of alkali or alkaline earth metal salt is 1 to 3 moles per mole of diamine, that of tertiary amine is 2 to 4 moles of hydrochloric diamine. In order to obtain the copolymers

  
 <EMI ID = 29.1>

  
or its hydrochloric acid salt is substituted by an aromatic diamine of the diphenyl series.

  
The resulting solution is cooled down to 0 to
20 [deg.] C and with stirring is added the dichloranhydride

  
 <EMI ID = 30.1>

  
aromatic from the diphenyl series. After loading the dichloranhydrides is introduced into the reaction mixture.

  
 <EMI ID = 31.1>

  
on the diamines) and stirring of the mixture is continued for a further 3 to 70 minutes while raising the temperature within the limits between 0 and 60 [deg.] C (the rise in temperature is conditioned by the release of heat. resulting from the polycondensation reaction and the mixing of the mixture). An increased viscosity of the reaction mixture is then observed even until it is transformed into a non-fluid mass. The mass content of the product

  
 <EMI ID = 32.1>

  
targeted product can be isolated in the mass in the form of a powder or porous granules.

  
To obtain the targeted product in powder form, <EMI ID = 33.1>

  
The polymer is synthesized and after its evacuation it is washed with water in order to remove the constituents of the solvent and it is dried at a temperature of 70 to 90 [deg.] C.

  
The powder obtained has an apparent weight of 0.3-0.4 g / ca.

  
To obtain the intended product in the form of granules, the mass mentioned is subjected to granulation (for example in a screw granulator). After washing with water and drying at a temperature of 70 to 90 [deg.] C, granules of 2 to 3 mm in diameter, 3 to 6 are obtained.

  
mm in length and an apparent density of 0.5 to 0.6 g / cm3.

  
Obtaining the targeted product in the form of granules makes it possible to simplify the washing operation and reduce

  
its duration. The granulated product is very convenient for preparing spinning solutions from it

  
in the manufacture of fibers.

  
 <EMI ID = 34.1>

  
according to the method in question, by the method of wet formation in the solution of concentrated sulfuric acid, fibers having a breaking strength of

  
 <EMI ID = 35.1>

  
meets the characteristics of known high mechanical strength fibers.

  
D &#65533; other characteristics and advantages of the invention will be better understood on reading and the following description of several concrete embodiments.

  
 <EMI ID = 36.1> 0.5 g / dl polymer solution, at a temperature of
25 [deg.] C according to the following formula:

  

 <EMI ID = 37.1>

Example I

  
In a 10 liter capacity stainless steel reactor equipped with a stirrer (about 100 rpm and a jacket to admit the coolant, 162 g (1.5

  
 <EMI ID = 38.1>

  
the solution obtained is cooled to 10-12 [deg.] C and with stirring 304.5 g (1.5 mol) of terephthalic acid dichlorohydride are added thereto. After loading the dichloroanhydride is introduced into the reaction mixture
294 ml (about 3.0 moles) of α-picolone, and its mixing is continued for 55 to 60 minutes. The mass obtained undergoes granulation, washing with water and drying at a temperature.

  
 <EMI ID = 39.1>

Example 2

  
In a 10 liter capacity reactor at a temperature of 23 to 25 [deg.] C for 10 minutes, 271.5 g (1.5 mol) of hydrochloric p-phenylenediamine and 79 g are dissolved.
(1.87 moles) of LiCl in 6 liters of dimethylacetamide containing 440 ml (4.5 moles) of α-picoline. The solution obtained is cooled for 4 minutes to a temperature.

  
 <EMI ID = 40.1>

  
(1.5 moles) of terephthalic acid dichloroanhydride.

  
After charging the dichloroanhydride, into the reaction mixture a further 294 ml (about 3.0 moles) of α-picoline is introduced. The reaction mixture is stirred for
55 to 60 minutes. The resulting mass is subjected to granulation, washing with water and drying at a temperature of
70 to 90 [deg.] C. The finished product looks like yellow granules

  
 <EMI ID = 41.1>

Example 3

  
The synthesis of pdly-p-phenyleneterephthalamide is carried out as in Example 2, except that the reaction mixture is stirred for 70 minutes after

  
 <EMI ID = 42.1>

  
The mass obtained has the appearance of powder. Once the powder has been removed from the reactor, it is washed with water until the components of the solvent have been removed and it is dried at a temperature of 70 to 90 [deg.] C. The powder obtained has an apparent density

  
 <EMI ID = 43.1>

Example 4

  
Into a 35 liter capacity stainless steel reactor fitted with a stirrer (about 110 rpm) and a jacket, 1267 g (7.0 mol) of hydrochloric p-phenylenediamine, 28.0 moles are charged. liters of dimethylacetamide,
370 g (about 8.73 moles) of LiCl and 2050 ml (21 moles) of α-picoline. Hydrochloric p-phenylenediamine is dissolved at a temperature of 20 to 25 [deg.] C with stirring for 15 minutes and the solution obtained is cooled to
15 [deg.] C. 1421 g (7 moles) of terephthalic acid dichloroanhydride are charged into the cooled solution with stirring for approximately 2 minutes, then introduced
1370 ml (14 moles) of a-picoline. The reaction mixture is stirred for? minutes. The mass obtained undergoes granulation, washing and drying as described in

  
 <EMI ID = 44.1>

  
5.18 dl / g.

Example 5

  
0.540 g (0.005 mol) of p-phenylenediamine are dissolved in a glass flask fitted with a stirrer in

  
 <EMI ID = 45.1>

  
heating in the water bath (the bath temperature is 50 to 60 [deg.] C) for 10 minutes. The solution obtained is discharged to 0 ° C. and with stirring, 1.015 g (0.005 mole) of terephthalic acid dichlorohydride is rapidly added thereto. After loading the dichloranhydride,

  
 <EMI ID = 46.1>

  
 <EMI ID = 47.1>

  
60 minutes. The resulting mass is discharged from the flask and mixed with water, precipitating the polymer. The polymer

  
 <EMI ID = 48.1>

  
The production of poly-p-phenyleneterephthalamide from p-phenylenediamine in Examples 6 to 11 is carried out under conditions similar to those described.

  
 <EMI ID = 49.1>

  
2.

  
TABLE 2

  

 <EMI ID = 50.1>

Example 12

  
In a 35 liter capacity reactor, we

  
 <EMI ID = 51.1>

  
of LiCl and 980 ml (10 moles) of α-picoline. Hydrochloric p-phenylenediamine is dissolved at a temperature of 20 to 25 [deg.] C with stirring for 15 minutes and the solution obtained is cooled to 15 [deg.] C. A mixture consisting of 355 g (1.75 mole) of terephthalic acid dichlorohydride and 488 g (1.75 mole) of 4-diphenyl acid dichlorohydride is placed in the solution cooled with stirring for 3 minutes, 4 -dicarboxylic. Then 980 ml (10 moles) of α-picoline are introduced into the reaction mixture, and the mixture is then stirred for a further 30 minutes.

  
 <EMI ID = 52.1>

Example 13

  
0.513 g (0.00475 mole) of p-phenylenediamine and 0.046 g (0.00025 mole) of benzidine are dissolved in a glass flask fitted with a stirrer in 20 ml of dimethylacetamide containing 0.5 g of LiCl, with heating on the water bath (the bath temperature being 50 to 60 [deg.] C) for 10 minutes. The solution obtained is cooled to 8 to 10 [deg.] C and with stirring is added quickly

  
 <EMI ID = 53.1>

  
ne and stirring is continued for 55 to 60 minutes. The product isolated as in Example 5 has a viscosity = 3.40 dl / g.

  
In Examples 14 to 23, the copolymers are obtained under conditions similar to those described in Example 13, using the aromatic diamines,

  
 <EMI ID = 54.1>

  
copolymers obtained.

  

 <EMI ID = 55.1>


  

 <EMI ID = 56.1>
 

  

 <EMI ID = 57.1>
 

  

 <EMI ID = 58.1>
 

  

 <EMI ID = 59.1>
 

Example 24

  
In a glass flask fitted with a stirrer, 0.2704 g (0.0025 mol) of p-phenylenediamine is dissolved in

  
 <EMI ID = 60.1>

  
of terephthalic acid dichloranhydride and 0.98 ml
(0.01 mol) of α-picoline and mixing of the reaction mass is continued for 60 minutes. The isolated polymer

  
 <EMI ID = 61.1>

  
in Examples 25 to 29 is carried out under conditions analogous to those described in Example 24 using

  
 <EMI ID = 62.1>

  
lymer obtained are shown in Table 4.

  
TABLE 4

  

 <EMI ID = 63.1>
 

Example 30

  
13.5796 g (0.075 mol) of hydrochloric p-phenylenediamine, 300 ml of dimethyl- are placed in a 0.5 liter capacity stainless steel reactor fitted with a stirrer and a jacket for the intake of the coolant.

  
 <EMI ID = 64.1>

  
coline. Hydrochloric p-phenylenediamine is dissolved at a temperature of 20 to 22 [deg.] C with stirring for 10 minutes and the resulting solution is cooled to 15 [deg.] C. In the cooled solution, while stirring, is introduced 15.225 g (0.075 mole) of acid dichloranhydride

  
 <EMI ID = 65.1>

  
The reaction mixture is stirred for 30 minutes. The mass obtained undergoes granulation, washed and dried as described in Example 1, obtaining the

  
 <EMI ID = 66.1>

  
In a reactor of 0.5 liter capacity are dissolved at 20-22 [deg.] C for 10 minutes 1 &#65533;, 5796 g (0.075 mol) of hydrochloric p-phenylenadiamine and 5.7 g of LiCl in 300

  
 <EMI ID = 67.1>

  
picoline. The resulting solution is cooled to 15 [deg.] C

  
and with stirring, 15.225 g (0.075 mole) of terephthalic acid dichlorohydride are added and then 14.8 ml
(0.15 mol) of α-picoline. The reaction mixture is stirred for 30 minutes. The mass obtained undergoes granulation, washed and dried as in Example 1. The product

  
 <EMI ID = 68.1>

Example 32

  
0.905 g (0.005 mol) of hydrochloric p-phenylenediamine are dissolved at a temperature of 20 to 22 [deg.] C in a glass flask fitted with a stirrer, in 20 ml of dimethylacetamide containing 0.3 g of LiCl and 1 , 2 ml (0.01 mol) of N-methylmorpholine for X) minutes. The resulting solution is cooled to 8-10 [deg.] C and while stirring 1.015 g (0.005 mol) of terephthalic acid dichlorohydride is added thereto. After loading the dichloran-

  
 <EMI ID = 69.1>

  
(0.01 mol) of N-methylmorpholine and stirring of the reaction mixture is continued for another 60 minutes. The product

  
 <EMI ID = 70.1>

  
hydrochloric diamine at a temperature of 20 to 22 &#65533; 'C in

  
 <EMI ID = 71.1>

  
methylacetamide containing 0.3 g of LiCl and 1.5 ml (0.01 mole) of dimethylbenzylamine for 10 minutes. The resulting solution is cooled to 8-10 [deg.] C and with stirring 1.015 g (0.005 mol) of terephthalic acid dichlorohydride is added thereto. After loading the dichloroanhydride, 1.5 ml (0.01 mol) are added to the reaction mixture.

  
of dimethylbenzylamine and stirring the reaction mixture for a further 60 minutes. The polymer isolated from

  
 <EMI ID = 72.1>

  
2.70 dl / g.

CLAIMS

  
<1> .- Process for obtaining poly-p-phenyleneterephthalamide or its copolymers by dissolving p-

  
 <EMI ID = 73.1>

  
aromatic diamine of the diphenyl series in amido-saline solvents consisting of linear or cyclic N-alkyl-substituted amides of acids and of alkali or alkaline-earth metal salts soluble in the amides indicated in an amount of from 1 to 3 moles per mole of diamines to be dissolved, with subsequent introduction into the solutions obtained, at a temperature of 0 to 20 [deg.] C, of the dichloroanhydride of terephbalic acid or of a mixture of the dichloranhydride of terephthalic acid and of di-

  
 <EMI ID = 74.1>

  
quantities equimolar to the diamines by obtaining a reaction mixture, with maintaining the reaction mixture under stirring for 3 to 70 minutes and isolation of the targeted product in the mass obtained, -characterized in that the amines are introduced into the reaction mixture before it is maintained tertiary at a rate of 2 to 6 moles per mole of initial diamines.


    

Claims (1)

2.- Method according to claim 1, characterized in that, to obtain the solution of p-phenylenediamine or the solution of p-phenylenediamine and diamine.aroma- <EMI ID = 75.1> hydrochloric diamine and the dissolution of the latter is carried out in the presence of tertiary amines at a rate of 2 to 4 moles per mole of hydrochloric p-phenylenediamine. 3.- Method according to claims 1 and 2, <EMI ID = 76.1> dimethylaniline, quinoline, pyridine, triethylamine, N-methylmorpholine. 4. A method according to claims 1 to 3, characterized in that for the isolation of the targeted product in the mass obtained, the latter undergoes granulation, washing with water and drying.