DE4202165A1 - Aramid copolymer with high tensile strength, modulus and elongation - useful for moulding, coating, film e.g. for membrane or fibre, e.g. for reinforcing elastomer - Google Patents

Abstract

Aromatic copolymers (I) with an intrinsic viscosity of at least 4.5 dl/g (0.25 wt. % soln. in NMP at 25 deg. C) which is soluble in organic polyamide solvents, contg. units of the formula (-OC-R1-CO-NR-R2-NH) (Ia), (Ib) (Ic) and opt. (-OC-R1-CO-NH-R3-H-) (Id) (Phe = 1,4-phenylene; Phe' = 1,3-phenylene) derived from mainly aromatic dicarboxylic acids and from aromatic diamines, 3,4'-diaminodiphenyl ether and 1,4-bis(4-aminophenoxy)benzene, are new. In formula, R1 = unsubstd. divalent aromatic gps. in which at least 80 mole-% of the valency bonds are in the para- or comparable coaxial or parallel positions and up to 20 mole % in the meta- or comparable angled positions; R2 = an unsubtd. divalent aromatic gp. with valency bonds in the parap- or comparable coaxial or parallel positions; R3 not R4 = R2 and = halo1,4-phenylene, -Phe-CO-NH-Phe or -Phe'-; and (I) contains 40-65 mol. % (Ia), 5-55 mole-% (b) 5-35 mole-% (Ic) and 0-30 mole-% (Id) units. (I) is prepd. by reacting a dicarbonyl dichloride of the formula C1OC-R1-COC1 (V) with a mixt. of the diamines H2N-R2-NH2 (VI), H2N-Phe(-O-Phe-NH2) (VII) H2N-Phe-O-Phe--NH2 (VIII) and opt. H2N-R3-NH2 (IX) in the required molar ratio. USE/ADVANTAGE - (I) is used for mouldings, pref. fibres, films or coatings esp. fibres with a tensile strength of over 150, esp. over 180 cN/tex and initial 100% (elastic) modulus of over 40 N/tex or a tensile strength of 90-150 cN/tex initial 100% modulus of 25-35 cN/tex and elongation at break of 4-6%; the fibre are used for reinforcing plastics, esp. elastomers, and the films making membranes (claimed). The fibres are useful e.g. for reinforcing fabrics for car tyres, etc. thermal insulation, filters and light insulation; and the films as heat-resistant electrical insulation and esp. as carrier for sepg. membranes. (I) has surprisingly good mechanical properties, is readily soluble and has good spinning property.

Description

The invention relates to new, aromatic copolyamides of Dicarboxylic acid diamine type, from their solutions in organic solvents can be spun as well as shaped structures made therefrom, such as Fibers, films and coatings with a very high initial modulus (Modulus of elasticity), and processes for their production.

Aromatic polyamides (polyaramides) are known to be raw materials of high thermal and chemical stability as well as low flammability. So show for example, fibers and films made from such raw materials have very good mechanical properties Properties such as high strength and high initial modulus (modulus of elasticity) and are well suited for technical applications - for example for Reinforcement of plastics or as filter materials.

It is known that threads or fibers made of polyaramides with high strength and high initial module can be produced if the amide bonds to the aromatic cores are oriented coaxially or almost parallel to one another, which creates rigid, rod-shaped polymer molecules.

A typical polyamide of this type is, for example Poly (p-phenylene terephthalamide). Threads made of this material are, for example, in the German patent 22 19 703.

This polyamide has a number of advantages, its production and its However, processing is very difficult. Because of the insolubility in polar organic solvents - even in the presence of inorganic Salts, such as calcium chloride or lithium chloride, as solubilizers - this falls  Polymer emerges from the reaction medium shortly after its formation. It must isolated, washed, dried and then redissolved in a spinning solvent will. Preferred solvent for the preparation of the spinning solutions is concentrated sulfuric acid, which poses special handling problems (Occupational safety, corrosion) and waste disposal.

Attempts have been made to circumvent these difficulties by: Copolyamides have been developed which have good solubility in the known Have amide solvents that are easy to spin and their Filaments after stretching due to high strength values and initial moduli award.

For example, in German Patent 25 56 883 and in German Offenlegungsschrift 30 07 063 copolyamides from terephthalic acid, p-Phenylenediamine and 3,4'-diaminodiphenyl ether described in Amide solvents provide isotropic solutions that are easy to spin. The Filaments achieve high strength and high tensile strength Moduli. The increased solubility is due to the meta-orientation and the Causes oxygen atom. However, there is still a need Aramids, which are made from known amide solvents to fibers with high Have strengths and moduli processed.

It has now been found that selected aromatic copolyamides are high Molecular weight can be processed into shaped structures that can be surprisingly good mechanical properties, such as high tear strengths, high Initial moduli and low elongations at break.

The present invention is therefore based on the object of further aromatic Provide copolyamides, which are characterized by a good solubility in Polyamide solvents and are characterized by good spinnability and the processed into shaped structures with good mechanical properties can.  

The copolyamides according to the invention are characterized by the presence selected aromatic diamine components in selected proportions.

The present invention relates to solvents soluble in organic polyamide solvents aromatic copolyamides with an inherent viscosity of at least 4.5 dl / g, measured at 25 ° C on solutions of 0.25% by weight of copolymer in N- Methylpyrrolidone, containing the recurring structural units of the formulas Ia, Ib, Ic and optionally Id

wherein at least 80 mol% of all residues R¹, based on the amount of these residues in the copolymer, mean an unsubstituted divalent aromatic residue whose valence bonds are in para- or in a comparable coaxial or parallel position to one another, and up to 20 mol% of all residues R¹ , based on the amount of these residues in the copolymer, mean an unsubstituted divalent aromatic residue, the valence bonds of which are in a meta or comparable angular position to one another,
R ^{2 is} an unsubstituted divalent aromatic radical, the valence bonds of which are in a para- or comparable coaxial or parallel position to one another,
R ^{3 represents} a radical of formula II or formula III or formula IV which deviates from R ²

where Hal is a halogen atom, and the proportion of the repeating structural units Ia, Ib, Ic and Id, based on the sum of these structural units in the copolymer, is within the following limits:
recurring structural unit of the formula Ia: 40 to 65 mol%, preferably 45 to 55 mol%;
recurring structural unit of the formula Ib: 5 to 55 mol%, preferably 35 to 45 mol%;
recurring structural unit of the formula Ic: 5 to 35 mol%, preferably 5 to 25 mol%; and
recurring structural unit of the formula Id: 0 to 30 mol%, preferably 0 or 10 to 15 mol%.

Contains a copolymer meta-residues, such as meta-residues R¹ or Remains of formula IV, so the amount of recurring moves Structural units of the formula Ib, preferably in the lower range of the specified Amount, for example 5 to 30 mol%.  

Any residues mean divalent aromatic residues whose Valence bonds are in para- or comparable coaxial or parallel Position to each other, so it is single or multi-core aromatic hydrocarbon radicals or heterocyclic aromatic radicals which can be single or multi-core. In the case of heterocyclic aromatic Residues have in particular one or two oxygen, nitrogen or Sulfur atoms in the aromatic nucleus.

Polynuclear aromatic radicals can be condensed with one another or via C-C bonds or linearly connected to one another via a -CO-NH group.

The valence bonds that are in coaxial or parallel to each other Stand, are directed in opposite directions. An example of coaxial, oppositely directed bonds are the biphenyl-4,4′-ene bonds. A Examples of parallel, oppositely directed bonds are e.g. B. the Naphthalene 1,5 or 2,6 bonds, while the naphthalene 1,8 bonds are rectified in parallel.

Examples of preferred divalent aromatic radicals, their valence bonds in a para- or comparable coaxial or parallel position to each other are mononuclear aromatic radicals with free para to each other Valences, especially 1,4-phenylene or dinuclear fused aromatic Residues with parallel, oppositely directed bonds, in particular 1,4-, 1,5- and 2,6-naphthylene, or dinuclear linked via a C-C bond aromatic residues with coaxial, oppositely directed bonds especially 4,4'-biphenylene.

Particularly preferred radicals R 1 and R ² are 1,4-phenylene.

Any residues mean divalent aromatic residues whose Valence bonds are in meta or comparable angled positions to each other, it is single or multi-core  aromatic hydrocarbon radicals or heterocyclic aromatic radicals which can be single or multi-core. In the case of heterocyclic aromatic Residues have in particular one or two oxygen, nitrogen or Sulfur atoms in the aromatic nucleus.

Polynuclear aromatic radicals can be condensed with one another or via CC bonds or via bridging groups such as B. -O-, -CH ₂ -, -CO-NH-, -S-, -CO- or -SO ₂ - linked together.

Examples of multinuclear aromatic radicals whose valence bonds are in meta position comparable angled position are 1,6-naphthylene, 2,7-naphthylene or 3,4'-biphenylene.

A preferred example of a mononuclear aromatic residue of this type is 1,3-phenylene.

Examples of HaI substituents in radicals of the formula II are bromine and in particular Chlorine.

To produce the copoylamides containing the recurring structural units Ia, Ib, Ic and optionally Id are expediently used as a dicarboxylic acid di chloride of the formula V with a mixture of the diamines of the formulas VI, VII, VIII and IX, if applicable

wherein the radicals R¹ to R ^{3 have} the meaning defined above.

The dicarboxylic acid dichloride of formula V and the individual types of diamonds can can also be used in the form of mixtures.

The proportions of diamines VI, VII and VIII and optionally IX are to be chosen so that polyamides with those defined above Quantities of structural units of the formulas Ia, Ib, Ic and optionally Id arise.

It is obvious to a person skilled in the art that the sum of all of aromatic Acid-derived structural units and the sum of all of aromatic Amine derived structural units are essentially the same, i. that is differ by a maximum of approximately 1%, preferably a maximum of 0.2%, especially within the scope of practical measurement and dosing options are the same.

The molecular weight of the resulting polyamides can be determined, inter alia the selection of the proportions of aromatic acids to aromatic Control amines. These selection criteria are known to those skilled in the art Polycondensation known.

Examples of suitable aromatic dicarboxylic acids, of which the Dicarboxylic acid dichlorides of the formula V are naphthalene-1,4-dicarboxylic acid, Naphthalene-1,5-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, Biphenyl-4,4'-dicarboxylic acid, 2-chloroterephthalic acid, 2-bromoterephthalic acid, 2-methyl terephthalic acid and especially terephthalic acid.

Up to 10 mol% of the dicarboxylic acid dichlorides can also differ from divalent ones derive aromatic meta residues. Examples of acids, of which there are Dicarboxylic acid dichlorides are naphthalene-1,6-dicarboxylic acid, Naphthalene-1,7-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, Biphenyl-3,4'-dicarboxylic acid and especially isophthalic acid.  

Examples of suitable diamines of the formula VI are naphthalene-1,4-diamine, Naphthalene-1,5-diamine, naphthalene-2,6-diamine, benzidine and in particular p-phenylenediamine.

The diamines of the formula VII (3,4′-diaminodiphenyl ether) and of the formula VIII (1,4- Bis- (4-aminophenoxy) benzene) are known per se.

Examples of suitable diamines of the formula IX are 2-chloro-1,4-phenylenediamine, 4,4'-diaminobenzanilide and m-phenylenediamine.

The copolymerization of the monomeric compounds described above is described in generally carried out as solution polymerization.

For this purpose, the aromatic monomers to be reacted with one another Compounds usually dissolved in an organic solvent. The Organic solvents preferably contain at least one solvent of the amide type, e.g. B. N-methyl-2-pyrrolidone, N, N-dimethylacetamide, Tetramethyl urea, N-methyl-2-piperidone, N, N'-dimethylethylene urea, N, N, N ′, N′-tetramethyl maleic acid amide, N-methylcaprolactam, N-acetylpyrrolidine, N, N-diethylacetamide, N-ethyl-2-pyrrolidone, N, N'-dimethylpropionic acid amide, N, N-dimethylisobutylamide, N-methylformamide, N, N'-dimethylpropyleneurea. For the process according to the invention are the preferred organic solvents N-methyl-2-pyrrolidone, N, N-dimethylacetamide and a mixture of these Connections of importance.

In a preferred form of carrying out the solution polymerization the aromatic monomeric diamines dissolved in an amide solvent. The so obtained solution is then with the at least one aromatic monomer Compound in the form of an aromatic dicarboxylic acid dihalide with violent Stir mixed to initiate copolymerization.  

The amide solvent is not only used as a solvent for the aromatic monomeric compounds and the aromatic copolyamide obtained therefrom but also used as an acid acceptor for a hydrogen halide, e.g. B. for Hydrogen chloride, which is a by-product of the copolymerization of aromatic monomeric compounds. In some cases it may be beneficial to have one to use the solubility-promoting additive, for example a Metal halide of one of the metals of group I or II of the periodic system, which of the copolymerization mixture before, during or after the Copolymerization is added.

Examples of such additives are alkali metal halides, such as lithium chloride or alkaline earth metal halides, such as calcium chloride.

The polycondensation temperatures are in solution polymerization usually between -20 ° C and + 120 ° C, preferably between + 10 ° C and + 100 ° C. Particularly good results are obtained at reaction temperatures between + 10 ° C and + 80 ° C achieved.

The sum of the concentrations of the aromatic monomeric compounds in The polymerization mixture solution can be made considering the desired Degree of polymerization, the desired viscosity of the polymerization mixture, the type of aromatic monomeric compounds used, the type of used solvent and the desired polymerization temperature can be set. The cheapest sum of the concentrations can determined on the basis of a series of preliminary tests for the course of the polymerization will.

Polycondensation reactions are preferably carried out so that after Completion of the reaction 2 to 15, preferably 5 to 12 wt .-% of polycondensate are present in the solution. Particularly good results are obtained at concentrations achieved from 5.0 to 8 wt .-%.  

In the course of the polycondensation, the molecular weight of the polymer and thus also the viscosity of the reaction mixture.

A sufficient molecular chain length is achieved when the viscosity of the Polycondensation obtained polymer solution of an inherent viscosity of the Polymers of more than 4.5, preferably more than 5.0 dl / g, in particular 5.5 to Corresponds to 8.0 dl / g.

Inherent viscosity is the expression

Roger that.

η _rel means the relative viscosity, c the concentration used in g / 100 ml.

It is determined for the purposes of the present invention on solutions of each 0.25% polymer in N-methylpyrrolidone at 25 ° C.

The sketched, known process for the production of aromatic Polyamides is as far as it is used to manufacture those described above serves aromatic polyamides according to the invention, also the subject of Invention.

When the polymer solution reaches the viscosity required for further processing has, the polycondensation in the usual way by adding monofunctional compounds, such as. B. Acetyl chloride can be stopped. The resulting salt-like solution can then be added to the amide solvent bound hydrogen chloride neutralized by adding basic substances will.  

For example, lithium hydroxide, calcium hydroxide, but especially calcium oxide.

The aromatic obtained when carrying out the process according to the invention Copolyamide can be separated from the copolymerization mixture by a separation process are deposited, for example by precipitation. To make one The solution for shaping the copolyamide is the aromatic thus obtained Copolyamide then dissolved in a suitable organic solvent, whereby this process as a dissolving process for producing the molding solution referred to as.

In cases where the aromatic copolyamide is produced according to the Invention using the method of solution polymerization is the Copolyamide because it is excellent in the solvent for the polymerization is soluble, but completely dissolved in it. Therefore it is for industrial use of the method according to the invention advantageous that obtained in the polymerization Mixture to be used immediately as a molding solution for the aromatic copolyamide.

The aromatic copolyamide according to the invention is in an organic Solvents, for example in organic solvents of the amide type excellently soluble and has excellent heat resistance and superior chemical resistance. The aromatic according to the invention Copolyamide is particularly useful for the manufacture of various shaped Articles, such as fibers, films and coatings, are also available The subject of the invention are.

The term "fibers" is in its broadest meaning within the scope of this description to understand; this includes, for example, filaments or staple fibers any titer.

The term "films" is also the broadest in the context of this description Understand meaning; this includes, for example, embodiments  of different thickness, such as foils or membranes.

The shaped structures not only have excellent heat resistance and chemical resistance, but also exhibit superior mechanical Properties, for example in terms of tensile strength, abrasion resistance and the modulus of elasticity. The solution of the aromatic copolyamide can can also be used in different ways, for example for Production of fibers, foils, sheet-like elements, fibrous materials and others shaped articles.

In the process for producing the aromatic molding solution As the solvent, copolyamide is preferably an amide type solvent used, especially the amide-type solvents mentioned above, or a mixture of two or more of the compounds mentioned.

For the preparation of the molding solution, it is advantageous if the concentration the aromatic copolyamide in a range between 4 and 15% by weight, in particular between 5 and 12 wt .-% is kept. If it is necessary, the molding solution can contain an additive to promote solubility, wherein at least one metal halide of a metal of groups I and II of Periodic table can be used, for example lithium chloride, Calcium chloride or magnesium bromide, in a concentration between 0.2 and 10%, preferably between 0.5 and 5%, based on the Total weight of the molding solution. The additive to promote solubility promotes the stability of the molding solution at elevated temperature.

The molding solution can be shaped into a shaped article after each suitable dry process, wet process or dry-wet process. In cases where a wet process is used, the molding solution for example, to form filaments, the forming solution or - in in this case - the spinning solution through a nozzle, for example a spinneret, in extrudes a coagulating liquid. It is usually advantageous if  the coagulation liquid from water or from an aqueous, a polar solution containing organic solvent. The polar organic solvents selected from the same amide solvents are usually used for dissolving the aromatic copolyamide will.

As a polar organic solvent is in the coagulation liquid preferably the same solvent used as in the molding solution is included. The coagulation liquid is preferably at a temperature between 0 ° C and the boiling point of the coagulation liquid Atmospheric pressure used.

The polar organic solvent is in the coagulation liquid preferably in a concentration of less than 70% by weight, in particular less than 50% by weight.

The molding process explained above is particularly for the production of Suitable for films or fibers from a molding solution.

In the production of fibers from the aromatic copolyamide, the Forming or spinning solution through a spinning head with several spinning openings extruded, the filamentary streams of the spinning solution in one of the above specified coagulation liquids are solidified (wet process) or in an atmosphere that promotes evaporation (dry process). One too a suitable variant is the so-called "dry nozzle wet spinning process" as it is e.g. B. is described in US-A-34 14 645. For spinning can be a common one Horizontal or vertical wet spinning machine, one Dry jet wet spinning machine, or a spinning machine used in which the material flow takes place under tension downwards.

When wet spinning an aromatic copolyamide according to the invention, the Coagulation preferably using a coagulation liquid  Additive to promote coagulation, with another coagulation Coagulation step follows, in the course of which the coagulating filaments of the aromatic copolyamide can be introduced into a water bath, which on a Temperature is kept between 0 and 100 ° C.

The additional coagulation step serves to complete the Coagulation by removing the solvent. It also uses additives to promote coagulation, if such substances are used, from the coagulated filaments washed out.

From the above description it is clear that the invention aromatic copolyamide using conventional spinning processes and -Devices can be easily processed into filaments without a dangerous or harmful solvent, such as B. concentrated sulfuric acid, should be used.

This reduces the dangers for the operating personnel. Furthermore the filaments produced from the copolyamide according to the invention have a dense internal structure.

The shaping solution can also be made using conventional fanning out or Extrusion process to be processed into a film.

Fibers or films made according to the molding process given above are usually subjected to stretching by not only the mechanical properties, such as. B. the tensile strength and Modulus of elasticity, but also the thermal properties, such as B. the thermal stability of the filaments or foils thus produced.

Filaments from the aromatic copolyamides according to the invention are in the Usually stretched to high mechanical strength and high To achieve modulus of elasticity. The draw ratio is  usually about 1: 6 to 1: 20. The drawing temperature is usually in this case between 250 and 500 ° C, preferably between 300 and 480 ° C.

The stretching can be done in a single step, in two steps or in several Steps are carried out, for heating a hot plate or a cylindrical heater can be used. In addition, the stretched filaments or foils of a further heat treatment with the same or higher temperature to be subjected to their crystalline structure promote. In this context it should be noted that the aromatic Copolyamide according to the invention not only in terms of its solubility in conventional organic solvents is surprisingly advantageous, but after Production of the fibers or films easily under "mild" Working conditions can be stretched.

The fibers obtainable from the copolymers according to the invention stand out due to high tensile strength and initial moduli and due to low elongation at break out.

A preferred subject of the present invention are fibers from the copolymers according to the invention which have a tensile strength of more than 150 cN / tex, in particular more than 180 cN / tex, and an initial module, based on 100% Elongation greater than 40 N / tex; Have fibers of this type in particular an elongation at break of up to 4%.

Another preferred object of the present invention are fibers made of the copolymers according to the invention which have a tear strength of about 90 to 150 cN / tex, an initial module, based on 100% elongation, of about 25 to 35 N / tex and an elongation at break of about 4 to 6%.

The aromatic copolyamide fibers according to the invention which possess excellent mechanical and thermal properties characterized by a high stretchability, can be used in a wide variety of ways  Be used industrially, for example to reinforce Plastics, in particular as reinforcing materials for the fabric inlays from Car tires and other rubber articles, as heat-resistant insulation materials, for the production of filter fabrics and as light insulation materials. Films from one Aromatic copolyamide according to the invention can be considered heat resistant electrical insulation materials are used, especially for production of membranes, for example as a carrier material for separation membranes.

Further properties and advantages of the invention are described below with reference to Examples explained in more detail.

It is understood, however, that the invention is not limited to the exemplary embodiments is limited. Rather, the specialist, starting from the Exemplary embodiments, numerous possibilities for changes and / or Additions to commandments without changing the basic idea of the invention would have to leave.

example 1 Aromatic copolyamide from 100 mol% terephthalic acid dichloride, 50 mol% p-phenylenediamine, 25 mol% 1,4-bis (4-aminophenoxy) benzene and 25 mol% 3,4'-diaminodiphenyl ether

162.2 g (1.5 mol) of p-phenylenediamine, 150.2 g (0.75 mol) of 3,4′-diaminodiphenyl ether and 219.3 g (0.75 mol) of 1,4-bis- (4- aminophenoxy) -benzene are dissolved in 14042 g of N-methylpyrrolidone under nitrogen and 607.3 g (3 mol) of terephthalic acid dichloride are added between 35 ° C. and 55 ° C. within 20 minutes. When the desired viscosity (η _inh = 5.5 dl / g) is reached, the polycondensation is stopped by adding 4.7 g of acetyl chloride and then neutralized with 328.2 g of calcium oxide (55% suspension in NMP). The solution is stirred at 120 ° C. The solution is filtered, degassed and wet spun. For this purpose, it is spun out of a nozzle with 100 openings, each 0.1 mm in diameter, into a coagulation bath consisting of an 80 ° C. solution of 35% N-methylpyrrolidone in water at a speed of 16 m / min. The threads obtained are stretched 11 times by two water baths, a washing machine, a dry galette and finally an iron at temperatures from 400 to 440 ° C.

The single filament titer is 1.91 dtex with a fineness-related strength of 190 cN / tex, an elongation of 4% and an initial modulus of 41 N / tex, based on 100% stretch.

Examples 2 to 25

According to the procedure described in Example 1, further aromatic Copolyamides manufactured, spun and tested. In the table below the diamines used, their proportions, the Solution viscosities of the polymers obtained, the spinning conditions and Properties of the fibers obtained are listed. In Table I are for the Monomers used the following abbreviations:

TPC = terephthalic acid dichloride,
IPC = isophthalic acid dichloride,
NDC = naphthalenedicarboxylic acid dichloride,
PPD = p-phenylenediamine,
3,4′-DADPE = 3,4′-diaminodiphenyl ether,
BAPOB = 1,4-bis (4-aminophenoxy) benzene,
4,4'-DABA = 4,4'-diaminobenzanilide,
CI-PPD = chloro-para-phenylenediamine.

Claims (11)

1. Aromatic copolyamide soluble in organic polyamide solvents with an inherent viscosity of at least 4.5 dl / g, measured at 25 ° C. in solutions of 0.25% by weight of copolymer in N-methylpyrrolidone, containing the recurring structural units of the formulas Ia , Ib, Ic and possibly Id wherein at least 80 mol% of all residues R¹, based on the amount of these residues in the copolymer, mean an unsubstituted divalent aromatic residue whose valence bonds are in para- or in a comparable coaxial or parallel position to one another, and up to 20 mol% of all residues R¹ , based on the amount of these residues in the copolymer, mean an unsubstituted divalent aromatic residue, the valence bonds of which are in a meta or comparable angular position to one another,
R ^{2 is} an unsubstituted divalent aromatic radical, the valence bonds of which are in a para- or comparable coaxial or parallel position to one another,
R ^{3 represents} a radical of formula II or formula III or formula IV which deviates from R ² wherein Hal is a halogen atom, and the proportion of the repeating structural units Ia, Ib, Ic and Id, based on the sum of these structural units in the copolymer, is within the following limits, repeating structural unit of the formula Ia: 40 to 65 mol%;
recurring structural unit of the formula Ib: 5 to 55 mol%;
recurring structural unit of the formula Ic: 5 to 35 mol%; and
recurring structural unit of the formula Id: 0 to 30 mol%. 2. Aromatic copolyamides according to claim 1, characterized in that at least 90 mol% of all radicals R¹, preferably 100 mol% of the radicals R¹, based on the amount of these residues, are 1,4-phenylene, and up to 10 mol% of all residues R¹, represent 1,3-phenylene based on the amount of these radicals. 3. Aromatic copolyamides according to claim 1, characterized in that R ^{2 is} 1,4-phenylene. 4. Aromatic copolyamides according to claim 1, characterized in that at least 90 mol% of all radicals R¹, preferably 100 mol% of the radicals R¹, based on the amount of these radicals, are 1,4-phenylene, and the proportion of the repeating structural units Ia, Ib, Ic and Id, based on the sum of these structural units, lies within the following limits:
recurring structural unit of the formula Ia: 45 to 55 mol%;
recurring structural unit of the formula Ib: 35 to 45 mol%;
recurring structural unit of the formula Ic: 5 to 25 mol%; and
recurring structural unit of the formula Id: 0 or 10 to 15 mol%. 5. A process for the preparation of copolyamides according to claim 1, characterized in that reacting a dicarboxylic acid dichloride of the formula V with a mixture of the diamines of the formulas VI, VII, VIII and optionally IX in which the radicals R¹ to R ^{3 have} the meaning defined in claim 1 and in which the molar proportions of the diamines of the formulas VI to IX, based on the sum of the proportions of these diamines, are chosen within such limits that a copolyamide with the defined in claim 1 Quantities of the recurring structural units of the formulas Ia, Ib, Ic and Id arise. 6. Shaped structures made from aromatic copolyamides according to claim 1. 7. Shaped structure according to claim 6, characterized in that it is Fibers, films or coatings. 8. Shaped structure according to claim 6, characterized in that it is Fibers that have a tensile strength of more than 150 cN / tex, in particular more than 180 cN / tex and an initial modulus, based on 100% elongation, of have more than 40 N / tex.   9. Shaped structure according to claim 6, characterized in that it is Fibers that have a tensile strength of about 90 to 150 cN / tex, a Initial modulus, based on 100% elongation, from about 25 to 35 cN / tex and one Have an elongation at break of 4 to 6%. 10. Use of fibers from aromatic copolyamides according to claim 1 for reinforcing plastics, in particular for reinforcing elastomers. 11. Use of films from aromatic copolyamides according to claim 1 for the production of membranes.