GB1595855A - Halogen-containing 1,3,5-triazine-dicarboxylic acid derivatives and their use as flameproofing agents in synthetic plastics - Google Patents

Description

(54) HALOGEN-CONTAINING 1 ,3,5-TRIAZINE-DICARBOXYLIC ACID DERIVATIVES AND THEIR USE AS FLAMEPROOFING AGENTS IN SYNTHETIC PLASTICS (71) We, CIBA-GEIGY AG, a Swiss Body Corporate, of Basle, Switzerland, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The present invention relates to halogen-containing heterocyclic dicarboxylic acids, to their acid halides, acid esters, acid amides and acid salts; to the use thereof as flameproofing agents in synthetic plastics; and to thermoplastic polyesters and polyamides containing, partially or completely, these dicarboxylic acids.

Thermoplastic polyesters, particularly polyalkylene terephthalates, have achieved commerical importance as valuable moulding compounds. For some applications, however, the properties of these polyesters do not satisfy the requirements they are expected to meet. In order to compensate for this disadvantage, additives are added to the polyester, or copolyesters with suitable comonomers are provided.

In order to impart to polyester a noninflammable finish, it is customary to add to the polyester a flameproofing agent. There have already also been suggested, however, halogen-containing monomeric dicarboxylic acids and diols, which are concomitantly incorporated into the polyester in order not to cause impairment of the mechanical properties, compared with that caused by the finish being imparted by addition of the said agents, see German Offenlegungsschrift No. 2,453,450; or in order to partially improve these properties when the noninflammable finish is imparted, e.g. the dimensional stability under heat. It is also known that this improvement in properties can be achieved with dicarboxylic acids containing an striazine ring, see German Offenlegungsschriften Nos. 2,533,675 and 2,533,715.

Also the monomers suggested hitherto are not without disadvantages. Thus the halogen-containing diols based on benzimidazolones are not very reactive, which necessitates uneconomical reaction times in the production of polyesters. Other diols have only a low thermal stability and decompose at the temperatures necessary for producing polyesters, e.g. brominated bisphenol. The known halogenated aromatic dicarboxylic acid tetrabromophthalic acid can be incorporated by condensation into the polyester chains only with difficulty, probably on account of the possible anhydride formation.

There is thus need for a flameproofing agent which can be used both as an additive and as an agent that can be incorporated into the polymer chains of a thermoplastic polyester or polyamide. At the same time, there must be no reduction or only a slight reduction in the thermal stability of the flameproofed polymers; there must be no discoloration or at most only a slight discoloration caused; and the polymers to which a noninflammable finish has been imparted must have good electrical properties. In some cases it should also be possible to obtain an improvement in the dimensional stability under heat (equal to a raising of the second order transition temperature).

It is the object of the invention to provide a flameproofing agent of this nature, and also the polymers flameproofed therewith, particularly polyesters and polyamides.

The present invention relates therefore to halogen-containing heterocyclic dicarboxylic acids of the general formula I

wherein R1 represents alkylene or cycloalkylene having I to 17 C atoms, phenylene, benzylene, halogenated phenylene and benzylene of the formulae

respectively, in which X represents chlorine or bromine atoms, and n represents an integer from 1 to 4, R2, R3 and R4 are identical or different and represent a hydrogen atom, alkyl or cycloalkyl each having 1 to 18 C atoms, phenyl, benzyl, or a halogenated phenyl or benzyl radical of the formulae

respectively, in which m represents an integer from 1 to 5, and X has the aforesaid meaning, with at least one of the radicals R' to R4 representing one of the halogencontaining groups: and to the acid halides, acid esters; acid amides and salts thereof.

In the formula I, n preferably represents 2, particularly 1, and m preferably represents 1--3, particularly 1 or 2. The symbol X preferably represents a bromine atom. As alkylene, R' preferably contains 1--12, especially 3-10, C atoms, and as cycloalkylene preferably 5-7, especially 6, ring carbon atoms. If R1 is phenylene.

it is preferably paraphenylene. If R' is benzylene, its methylene group is preferably bonded to the N atom, and it is preferably the p-benzylene group.

As alkyl and cycloalkyl, R2 preferably contains 1 to 12, particularly 1 to 4, C atoms and 5-7, preferably 6, ring carbon atoms, respectively, and represents in particular phenyl, halogenated phenyl and, more especially, a hydrogen atom.

R3 and R4 can be different but are preferably identical, and are preferably a hydrogen atom, alkyl having 1--12, particularly 1H, C atoms, phenyl or ialogenated phenyl.

Preferably, R1 and/or R3 and R4 represent the halogen-containing groups. The position of the chlorine or bromine atoms in the mono- or divalent halogenophenyl and halogenobenzyl radicals depends here essentially on the halogenation sequence and on the production method. In the production process, there can also be formed mixtures of differing degrees of halogenation, which likewise fall within the scope of the present invention. Examples of R' to R4 as halogenated groups are: p-bromo- or p-chlorohenyl and p-bromo- or p-chlorobenzyl, 2,4-dibromo- or 2,4 dichlorophenyl and,4-dib romo- or 2,4-dichlorobenzyl, 2,4,6-tribromo- or 2,4,6- trichlorophenyl and 2,4,6-tribromo- or 2,4,6-trichlorobenzyl, 2-bromo- or 2chlorophenylene and 2-bromo- or 2-chlorobenzylene, 2,6-dichloro- or 2,6dibromophenylene and 2,6-dichloro- or 2,6-dibromobenzylene, or tetrachloro- or tetrabromophenylene and tetrachloro- or tetrabromobenzylene.

Further examples of R' and R4 are methyl, ethyl, propyl, i-propyl, n-, i- or tbutyl, pentyl, hexyl, octyl, nonyl, decyl, undecyl, dodecyl, tetradecyl, heptadecyl, cyclopentyl, cyclohexyl, cycloheptyl, phenyl or benzyl, and their divalent representatives of the alkylene, cycloalkylene, alkylidene or cycloalkylidene series, as well as phenylene and benzylene.

Preferred compounds are 2 - [bis - (4 - bromophenyl) - amino] - 4,6 - bis (4 - carboxyanilino) - s - triazine and 2 - [bis - (4 - bromophenyl) - amino] 4,6 - bis - (2 - bromo - 4 - carboxylanilino) - 5 triazine.

The invention relates also to acid derivatives, by which are meant the compounds of the formula I which are modified on one carboxyl group or preferably on both carboxyl groups. These can be the acid halides, preferably the bromides and chlorides, and also the esters, amides and salts.

The esters can be formed from alcohols which can contain, for example, I to 24 or 1 to 18 C atoms, and which are derived from alkanols, cycloalkanois, or optionally alkyl-substituted phenols or benzyl alcohols.

The acid amides can be formed from ammonia or from primary or secondary amines, which contain, for example, 1 to 24 or 1--18 C atoms. The substituents can be alkyl, cycloalkyl or optionally alkyl-substituted phenyl or benzyl.

In the case of the salts, these can be ammonium salts or metal salts. The ammonium salts can be derived from ammonia and from primary, secondary as well as tertiary amines. The metal salts can be derived from the metal elements of the main groups, subgroups and transition groups of the periodic system. A preferred group of metals are those which further improve noninflammability, for example alkali metals and alkaline-earth metals.

The dicarboxylic acid, or derivatives thereof, according to the invention can be produced by processes known per se. Besides the direct chlorination and/or bromination, there are also suitable the processes described in the German Offenlegungsschrift No. 2,121,184. The dicarboxylic acids according to the invention are produced by a process wherein a) a compound of the formula II

wherein R' to R4 represent the halogen-free radicals of the dicarboxylic acids of the formula 1, with at least one of the radicals R' to R4 representing phenyl, benzyl or phenylene or benzylene, or partially brominated and/or chlorinated radicals derived therefrom, and R5 being halogen, hydroxyl, an alcohol radical or amino radical, or the group MO- wherein M represents a cation, is brominated and/or chlorinated: or b) 1 mol of dichloro-s-triazine aminosubstituted with the R3R4N group is reacted with 2 mols of amino acid or amino acid ester of the formula

or 1 mol of monochloro-s-triazine disubstituted with the

group is reacted with 1 mol of amine of the formula R3,R4NH, wherein the radicals R1 to R5 have the aforementioned meanings, and at least one of the radicals R' to R4 represents a halogen-containing group.

By partially brominated and/or chlorinated radicals in the reaction a) are meant those phenyl, benzyl, phenylene or benzylene radicals which contain hydrogen atoms replaceable by bromine or chlorine.

The reaction a) can be performed by a process wherein a triazinedicarboxylic acid of the formula II, or derivatives thereof (produced e.g. by the processes of the German Offenlegungsschrift No. 2,121,184), is dissolved or suspended in a suitable inert organic solvent, e.g. glacial acetic acid, and, advantageously with the addition of a catalyst and of a hydrogen-halide-binding agent, reacted with chlorine and/or bromine. The reaction temperatures are preferably between 0 C and 1200C. The desired halogen-containing dicarboxylic acids crystallise generally from the reaction mixture, or they can be precipitated and recrystallised for purification.

The general process b) for producing the dicarboxylic acids or derivatives thereof, according to the invention is suitably carried out by reacting cyanuric acid chloride, or an amino-substituted dichloro-s-triazine, with an amino acid or amino ester in the presence of a base and water in the temperature range preferably of 0 to 100 C.

Stated more precisely, the compounds according to the invention can be produced essentially according to two process variants which are given in the following: Process 1 The amino-blocking group is firstly introduced into the triazine nucleus by reacting cyanuric acid chloride with a suitable amino compound at a temperature of about 0 to 100C in the presence of a base. This is a general process which is described by Thurston et al., J. Am. Chem. Soc., 73, 2992(1951). The second stage comprises reacting the amino-substituted dichloro-s-triazine, formed as intermediate, with an amino acid or with one of the derivatives thereof, e.g. an amino ester, with the two chlorine atoms being replaced by the amino acid groups or, e.g., amino ester groups. The last-mentioned reaction is performed in boiling water in the presence of a base.

Process 2 In this process, the two amino acid groups or, e.g., amino ester groups are firstly introduced into the triazine nucleus, and then the blocking group is introduced into the nucleus. This is effected by reacting cyanuric acid chloride with a suitable amino acid, or e.g. with a suitable amino acid ester, at a temperature of 30 to 600 C, preferably at 40 to 600 C. The product from the first reaction is then reacted with the amino compound containing the desired blocking groups. This reaction is performed at reflux temperature, in the presence of a base, in an aqueous medium. In the above reactions in which a base is necessary, bases such as sodium hydroxide or potassium hydroxide or sodium carbonate are advantageously used.

It is often expedient to produce the amino acid salt, which can be used in the manner described above, in situ by means of basic hydrolysis of the corresponding lactam, for example of -caprolactam.

Although the triazine-amino acid derivatives can be produced either in water or in organic solvents, the aqueous medium is preferred. Since the salts of the triazine-amino acids are soluble in water, the course of the reaction can be followed by observing the disappearance of the insoluble cyanuric acid chloride, or of the dichlorotriazine compound which is amino-substituted, which are used as starting materials, from the aqueous solution. The separation and purification stage is likewise more successful because the insoluble unreacted triazine compound used as starting material can be filtered off from the solution after completion of the reaction. A product precipitates on acidification of the filtered solution. The unreacted amino acids and salts, which have been formed furing the reaction, remain in the aqueous phase.

In the production of the triazine-amino esters, organic solvents are preferred as the reaction medium. Organic solvents suitable for this purpose include ethers such as tetrahydrofuran or dioxane, or aliphatic and aromatic hydrocarbons such as heptane, methylcyclohexane, benzene or toluene: It is also to be mentioned that obviously there is also the possibility for the production of the dicarboxylic acid derivatives by starting with the dicarboxylic acids, or for the production of the dicarboxylic acids by, e.g., hydrolysing the dicarboxylic acid esters according to the invention.

The dicarboxylic acids, or the acid derivatives thereof, according to the invention are in general colourless to yellowish, crystalline compounds which are readily soluble in many organic solvents. They have surprisingly high thermal stability, i.e. in comparison with that of the corresponding non-halogenated dicarboxylic acids, their stability is reduced to only a slight or negligible degree.

The dicarboxylic acids of the formula I and the acids derivatives thereof according to the invention are therefore excellently suitable as flameproofing agents for thermoplastic polymers since no decomposition has to be feared on incorporation of the agents by customary methods. In general, amounts of 0.1 to 15, preferably I to 10, per cent by weight, relative to the total mixture, are incorporated.

The present invention therefore relates also to noninflammable thermoplastic moulding compounds containing a thermoplastic polymer and a dicarboxylic acid of the formula I or an acid derivative thereof.

Examples of suitable thermoplastic polymers are the following thermoplasts.

1. Polymers which are derived from hydrocarbons with single or double unsaturation, such as polyolefines, for example polyethylene which can optionally be crosslink-ed, polypropylene, polyisobutylene, polymethylbutene- 1, polymethylpentene-l, polybutene-l, polyisoprene, polybutadiene, polystyrene, polyisobutylene, copolymers of the monomers on which the homopolymers mentioned are based, such as ethylene-propylene copolymers propyleneisobutylene copolymers, styrene-butadiene copolymers, and also terpolymers of ethylene and propylene with diene, such as hexadiene, dicyclopentadiene or ethylidenenorbornenes; mixtures of the abovementioned homopolymers, such as mixtures of polypropylene and polyethylene, polypropylene and polybutene-l, or polypropylene and polyisobutylene.

2. Polyamides and copolyamides which are derived from diamines and dicarboxylic acids and/or from aminocarboxylic acids or the corresponding lactams, such as polyamide 6, polyamide 6/6, polyamide 6/10, polyamide 11 and polyamide 12.

3. Polyesters which are derived from dicarboxylic acids and dialcohols and/or from hydroxycarboxylic acids or from the corresponding lactones, such as polyethylene terephthalate poly- 1 ,4-dimethylol-cyclohexane terephthalate, polypivalolactone and poly-1,4-butylene terephthalate.

4. Polyacrylonitrile and also copolymers thereof with other vinyl compounds, such as acrylonitrile/butadiene/styrene, acrylonitrile/styrene and acrylonitrile/styrene/acrylic ester copolymers.

5. Polyurethanes and polyureas.

6. Polyacetals, such as polyoxymethylene and polyoxyethylene, and also those polyoxymethylenes containing ethylene oxide as the comonomer.

Beforehand, afterwards or together with the dicarboxylic acids of the formula I used according to-the invention, there can be added to the plastics the customary additives used for processing and for improving the properties of these polymers, for example plasticisers, thermostabilisers, antioxidants, dyes, fillers, especially reinforcing fillers such as sized glass fibres, lubricants, light stabilisers and flameproofing agents.

Incorporation of the dicarboxylic acids to be used according to the invention can be effected after polymerisation, for example by mixing the substances, and optionally further additives, into the melt by methods customary in the art, before or during shaping. The dicarboxylic acids or derivatives thereof can also be incorporated in the form of a master batch, which contains these compounds for example at a concentration of 2.5 to 25 / by weight, into the thermoplastic polymers.

A further field of application of the dicarboxylic acids of the formula I and derivatives thereof is their application as biocidal active substances.

The dicarboxylic acids according to the invention and some of the derivatives thereof are excellently suitable as internal flameproofing agents for polyesters and polyamides; for this application the dicarboxylic acids of the formula 1, or the polyester-forming or polyamide-forming derivatives thereof, are incorporated into the polymer chains of the polyesters or polyamides during manufacture of these polyesters or polyamides. The dicarboxylic acids of the formula I and the derivatives thereof have such a surprisingly high thermal stability that they undergo virtually no decomposition under the conditions of manufacture, and the resulting polymers are so stable under heat that they can be processed by the usual methods into moulded articles of all kinds.

The present invention therefore relates also to halogen-containing thermoplastic polyesters and polyamides of which the dicarboxylic acid proportion (exact proportion of the dicarboxylic radicals) consists partially or completely of dicarboxylic acids of the formula I.

The polyesters and polyamides can be formed from aliphatic, cycloaliphatic and/or aromatic dicarboxylic acids, hydroxy- or aminocarboxylic acids and diols or diamines, with the respective composition being governed by considerations with regard to economy and to application techniques.

The aliphatic dicarboxylic acids can contain 2 to 40, preferably 2-36, particularly 6-36 C atoms; the cycloaliphatic dicarboxylic acids 6 to 10 C atoms: the aromatic dicarboxylic acids 8 to 14 C atoms; the aliphatic hydroxycarboxylic acids 2 to 12 C atoms; and the aromatic, such as cycloaliphatic, hydroxycarboxylic acids 7 to 14 C atoms.

The aliphatic diols can contain 2 to 12 C atoms, particularly 2--6 C atoms, the cycloaliphatic diols 5 to 8 C atoms and the aromatic diols 6 to 16 C atoms. Diols designated as aromatic diols are those in which two hydroxyl groups are bonded to hydrocarbon radicals of aromatic character.

Tt is also possible for the polyesters to be branched with a small amount, e.g.

0.1 to 3 mol-%, of monomers that are more than bifunctional (e.g. pentaerythritol or trimellitic acid).

Suitable dicarboxylic acids are linear and branched, saturated aliphatic dicarboxylic acids, aromatic dicarboxylic acids and cycloaliphatic dicarboxylic acids.

Suitable aliphatic dicarboxylic acids are those having 2--40 C atoms, e.g.

oxalic acid, malonic acid, dimethylmalonic acid, succinic acid, octadecylsuccinic acid, pimelic acid, adipic acid, trimethyladipic acid, sebacic acid, azelaic acid and dimeric acids (dimerisation products of unsaturated aliphatic carboxylic acids such as oleic acid) or alkylated malonic and succinic acids such as octadecylsuccinic acid.

Suitable cycloaliphatic dicarboxylic acids are: 1,3-cyclobutanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,3- and l,4-cyclohexanedicarboxylic acid or 1,3- and 1,4- dicarboxylmethylcyclohexane-4,4'-dicyclohexyldicarboxylic acid.

Suitable aromatic dicarboxylic acids are: in particular terephthalic acid, isophthalic acid, o-phthalic acid, as well as 1,3-, 1,4-, 2,6- or 2,7naphthalenedicarboxylic acid, 4,4'-diphenyldicarboxylic acid, 4,4'diphenylsulphonedicarboxylic acid, 1,1,3 - trimethyl - 5 - carboxyl - 3 - (p carboxylphenyl) - indane, 4,4' - diphenyl - ether - dicarboxylic acid or bis - p (carboxylphenyl) - methane.

The aromatic dicarboxylic acids are preferred, and among them in particular terephthalic acid, isophthalic acid and orthophthalic acid, also 1,4cyclohexanedicarboxylic acid, and aliphatic dicarboxylic acids having 2 to 36 C atoms, preferably 6-36 C atoms.

Further suitable dicarboxylic acids are those containing -CO-NH- groups; they are described in the German Offenlegungsschrift No. 2,414,349. Also suitable are dicarboxylic acids containing N-heterocyclic rings, e.g. those which are derived from carboxyl-alkylated, carboxyl-phenylated or carboxyl-benzylated monoaminos-triazinedicarboxylic acids (see German Offenlegungsschriften Nos. 2,121,184 and 2,533,675), mono- or methylenebishydantoins, optionally halogenated benz imidazolones, or parabanic acid. The carboxyalkyl group in these cases can contain 3 to 20 C atoms.

Suitable aliphatic diols are the linear and branched aliphatic glycols, especially those having 2 to 12 C atoms, particularly 2-6 C atoms, in the molecule; e.g.: ethylene glycol, 1,2- or 1,3-propylene glycol, 1,2-, 1,3-, 2,3- or 1,4-butanediol, pentyl glycol, neopentyl glycol, 1,6-hexanediol or 1,12-dodecanediol. A suitable cycloaliphatic diol is, e.g., 1,4-dihydroxycyclohexane. Further suitable aliphatic diols are, e.g., l,4-dihydroxymethylcyclohexane, aromatic-aliphatic diols such as pxylylene glycol or 2,5-dichloro-p-xylylene glycol, and also polyoxaalkylene glycol such as diethylene glycol, triethylene glycol or polyethylene glycol. The alkylenediols are preferably linear and contain in particular 2 to 4 carbon atoms.

Preferred diols are the alkylenediols, 1,4-dihydroxycyclohexane and 1,4dihydroxymethylcyclohexane and N,N-heterocyclic diols. Ethylene glycol and 1,4butane diol are especially preferred.

Further suitable diols are A-hydroxyalkylated, particularly p-hydroxyethylated, bisphenols, such as 2,2-bis-[4'-(p-hydroethoxy)-phenyl]-propane. Further bisphenols are mentioned later.

A further group of aliphatic diols are those N,N-heterocyclic diols of the general formula

wherein R8 represents methyl and, preferably, a hydrogen atom, and X represents a radical of the formula

wherein R7, R8 and R9 independently of one another represent alkyl having 1 to 4 C atoms, or together they represent tetra- or pentamethylene, and the R'Os independently of one another represent a hydrogen, chlorine or bromine atom.

These diols are known and are described, e.g., in the German Offenlegungsschriften Nos. 1,812,003, 2,342,432, 2,342,372 and 2,453,326.

Examples are: N,N' - bis ( - hydroxyethl)- 5,5- dimethyl) - hydantoin, N,N' - bis - ( - hydroxypropyl - 5,5 - dimethyl) - hydantoin, methylene - bis [N,N' - ( - hydroxyethyl) - 5 - methyl - 5 - ethylhydantoin], methylene - bis - [N - ( - hydroxyethyl) - 5,5 - dimethylhydantoin], N,N' - bis - (P - hydroxyethyl) - benzimidazolone, N,N' - bis - (tetrachloro) - benzimidazolone or N,N' - bis - (tetrabromo) - benzimidazolone.

Preferably, the R6s are each a hydrogen atom, R', R8 and R9 are each methyl, and all the R10s are each a hydrogen, chlorine or bromine atom.

Suitable aromatic diols are mononuclear diphenols, and particularly binuclear diphenols which carry on each aromatic nucleus a hydroxyl group. By aromatic are meant hydrocarbonaromatic radicals, such as phenylene or naphthylene. In addition t6 for example hydroquinone, there are also to be mentioned in particular the bisphenols which can be represented by the following formula

The hydroxyl groups can be in the m-positon, particularly however in the pposition. In this formula, R' and R" can each represent alkyl having 1 to 6 C atoms, halogen such as chlorine or bromine, and especially a hydrogen atom. A can represent a direct bond, or O, S, SO2, optionally substituted alkylidene, cycloalkylidene or alkylene.

Examples of optionally substituted alkylidene are: ethylidene, 1,1- or 2,2propylidene, 2,2-butylidene, 1,1 -isobutylidene, pentylidene, hexylidene, heptylidene, octylidene, dichloroethylidene or trichloroethylidene. Examples of optionally substituted alkylene are: methylene, ethylene, phenylmethylene, diphenylmethylene or methylphenylmethylene. And examples of cycloalkylidene are: cyclopentylidene, cyclohexylidene, cycloheptylidene and cyclooctylidene.

Examples of bisphenols are: bis - (p - hydroxyphenyl) - ethy or -thioether, bis - (p - hydroxyphenyl) - sulphone, bis - (p - hydroxyphenyl) - methane, 1,2 bis - (p - hydroxyphenyl) - ethane, 1 - phenyl - bis- (p- hydroxyphenyl)- methane, diphenyi bis- (p- hydroxyphenyl)- methane, 2,2 - bis - (4' hydroxy - 3' - methylphenyl) - propane, 1,1 - or 2,2 - bis - (p - hydroxyphenyl) butane, 1,1 - dichloro- or 1,1,1 - trichloro - 2,2 - bis - (p - hydroxyphenyl) ethane, 1,1 - bis - (p - hydroxyphenyl) - cyclopentane and particularly 2,2 - bis (p - hydroxyphenyl) - propane (bisphenol - A) and 1,1 - bis - (p hydroxyphenyl) - cyclohexane (bisphenol - C).

Suitable hydroxycarboxylic acids or lactones are, e.g., caprolactone, pivalolactone, 4-hydroxycyclohexanecarboxylic acid or 4-hydroxybenzoic acid.

The content of dicarboxylic acids of the formula I in polyesters according to the invention is in general 0.5-50 mol %, relative to the polyester. If the range of properties of the polyester is to be determined by the dicarboxylic acid of the formula I, this will be predominantly present in the polyester, e.g. to the extent of 30-50 mol %, preferably 40-50 mol %. If a noninflammable finish is to be imparted to known polyesters, a content of 1--15 mol %, preferably 2-8 mol ",,, is in general sufficent. A preferred subgroup of these polyesters is that comprising those having a glass transition temperature (Tg) of at least 1000C. A further subgroup is formed by those polyesters having a content of 0.5 to 8 mol q;,, preferably 1 to 5 mol %, of dicarboxylic acids of the formula I, at least 30 mol ,', of terephthalic acid and/or isophthalic acid and, as diols, linear alkylenediols having 2 to 4 C atoms, I-cyclohexanediol or 1,4-dihydroxymethylcyclohexane. These polyesters are particularly suitable for producing fibres.

The polyamides according to the invention are preferably formed from terephthalic acid; aliphatic dicarboxylic acids preferably having 6-12 C atoms: and either alkylenediamines having 2 to 12 C atoms, particularly 6 to 12 C atoms, and optionally aminocarboxylic acids preferably having 6 to 12 C atoms, or these aminocarboxylic acids alone.

The relative minimum viscosity of the polyesters is 1.3, but preferably the relative viscosity is 1.3 to 4.0, especially 1.3 to 3.0.

The polyesters and polyamides according to the invention are obtained by known processes wherein partially or completely a dicarboxylic acid of the formula I or polyester-forming or polyamide-forming derivatives thereof, as the dicarboxylic acid constituent, is concomitantly incorporated by condensation, and polycondensed to the desired viscosity. The process is in general performed at a temperature of 50 to 3200C under normal pressure, or in vacuo and/or in a stream of inert g temperatures below the melting point of the granulate being applied. Higher viscosities can be obtained in this manner.

During processing of the polyester or polyamide melt, or even before the polycondensation reaction, there can be added to the reaction mixture inert additives of all kinds, for example fillers or reinforcing fillers, such as talcum, kaolin, metal powders, wollastonite, glass balls and particularly glass fibres, inorganic or organic pigments, optical brighteners, delustering agents, internal lubricants, agents promoting crystallisation, and further flameproofing agents, e.g.

synergistically acting compounds, such as antimony trioxide. If the polycondensation reaction is performed discontinuously, the inert additives can be added during the final condensation stages, e.g. during solid-phase condensation or at the end of the melt condensation stage.

The polyesters and polyamides according to the invention can be partial) crystalline or amorphous, depending on which diols or diamines and which dicarboxylic acids are used as starting components, and in which quantity ratios these are employed. They are colourless to yellow in shade, and constitute thermoplastic, difficultly combustible materials (engineering plastics) from which can be produced by the customary moulding processes, such as casting, injection moulding and extruding, moulded articles having valuable properties. Examples of such moulded articles are technical apparatus parts, apparatus housings, domestic equipment, sports equipment, electric insulation, automobile components, switch gear, sheets, films, and semi-products which can be shaped by machining. Also possible is the application for coating articles by known powder-coating processes or from solutions, and also the application for the production of fibres. A particular field of application is that for shaped articles for the electrical industry, since the polyesters have surprisingly good electrical properties.

The flameproofed polyesters and polyamides according to the invention can be easily produced since the dicarboxylic acids of the formula I and the polymerforming derivatives react well. The internal flameproofing effect can be so controlled that it is reproducible. The polyesters are surprisingly only slightly discoloured, even after processing into shaped articles, a factor which can be attributed essentially to the surprisingly high thermal stability of the polyesters. The mechanical properties too are excellent.

The polyesters produced according to the following Examples are more precisely characterised by the following characteristic values. The polyesters are characterised by those morphological changes which are measured by means of differential thermoanalysis on a specimen tempered for 3 minutes at 300C above the melting point or softening point and then rapidly quenched. The quenched specimen is heated at a heating rate of 16"C/minute by means of the differential scanning calorimeter "DSC-IB", Perkin-Elmer. The thermogram of the specimen shows the glass transition temperature (Tg) [also called second order transition temperature], the crystallisation temperature (Tc), the crystallite melt temperature (Tm) and the decomposition temperature (Td).

The point of inflection where there occurs a sudden increase in the specific heat in the thermogram is given as the glass transition temperature; the tip of the exothermal peak as the crystallisation temperature; the tip of the endothermic peak as the melting temperature; and the point at which the sudden exo- and endothermic fluctuations of the specific heat commence is given as the decomposition temperature (Td). The relative viscosity of the polycondensates of the Examples is determined on solutions of 1 g of polyester in 100 ml of a mixture consisting of equal parts of phenol and symmetrical tetrachloroethane, at 30"C.

The softening temperature (T9) is determined on a hot-stage microscope according to Kofler with a heating-up rate of 150C/minute, by which system a cross is formed from 2 filaments, and the softening temperature is defined as being that temperature at which the sharp angles of the cross disappear.

The following Examples serve to further illustrate the invention.

Example I 2-[Bis-(4-bromophenyl)-amino]-4,6-bis-(4-carbethoxyanilino)-s-triazine (I) In a glass apparatus provided with stirrer, reflux condenser, dropping funnel and thermometer, 28.7 g (0.05 mol) of 2-diphenylamino-4,6-bis-(4carbethoxyanilino)-s-triazine and 8.2 g (0.1 mol) of sodium acetate are heated together with 0.5 g of iodine as catalyst, in 300 ml of glacial acetic acid to 600 C; and subsequently 16 g (0.1 mol) of bromine, dissolved in 50 ml of glacial acetic acid, is added dropwise within one hour. After completion of the addition, the reaction mixture is held at 600C for a further 6 hours. After cooling to room temperature, the product which has crystallised out is washed with glacial acetic acid and water, and then dried at 1000C in in vacuo to yield 28 g (78% of theory) of colourless crystalline crude product. For analysis, the product is recrystallised from glacial acetic acid: m.p. 252--258"C.

Elementary analysis: calculated (for C33H28N6O4) found 54.11% C 53.9(C 3.85% H 4.0 /O H 11.47% N 11.3% N 21.82% Br 20.7%Br The 'H-NMR spectrum indicates the following structure:

Example 2 2-[Bis-(4'-bromophenyl)-amino]-4,6-bis-(2"-bromo-4"-carbethoxyanilino)-s- triazine (II) In the glass apparatus according to Example 1, 114.9 g (0.2 mol) of 2 diphenylamino-4,6-bis-(4-carbethoxyanilino)-s-triazine and 73.8 g (0.9 mol) of sodium acetate are heated, together with 2 g of iodine, in 1500 ml of glacial acetic acid to 1000C; and there is then added dropwise, in about 4 hours, 134.4 g (0.84 mol) of bromine. After completion of the addition, the temperature is maintained at 100 C for a further 4 hours. Further processing is carried out as in Example 1 to obtain 159 g (89.9% of theory) of colourless crystalline crude product having a melting point of 246-248 C. For analysis, the product is recrystallised from dioxane: m.p. 251--254"C.

Elementary analysis calculated (for C33H26N6O4Br4) found 44.52% C 43.9% C 2.94% H 3.0% H 9.44% N 9.4% N 35.90% Br 34.8% Br The 'H spectrum and '3C-NMR spectrum indicate the following structure:

Example 3 2-(2',4',6'-Tribromoanilino)-4,6-bis-(4"-carbethoxyanilino)s-triazine (III) 33.5 g (0.07 mol) of 2-(2'-4',6'-tribromoanilino)-4,6-dichlorotriazine in 100 ml of chlorobenzene is refluxed together with 23.1 g (0.14 mol) of ethyl paminobenzoate- for 8 hours. After the addition of 15 g of sodium carbonate in 20 ml of water, the reaction mixture is refluxed for a further hour. After cooling, the reaction product which has crystallised out is filtered off with suction, washed with water and dried. There is thus obtained 49 g (95% of theory) of compound III as colourless crystalline powder; m.p. 168--171"C.

Elementary analysis: calculated (for C27H23Br3N6O4) found 44.1% C 44.2% C 3.15%H 3.2%H 11.43% N 11.2% N 32.6% Br 32.3% Br Example 4 2-[Bis-(4'-bromophenyl)amino]-4,6-bis-(carboxymethylamino)-s-triazine (IV) 19.7 g (0.05 mol) of 2-diphenylamino-4,6-bis-(carboxymethylamino)-s-triazine and 9 g (0.11 mol) of sodium acetate in 150 ml of glacial acetic acid are heated to 800C, and there is then slowly added a solution of 16.8 g (0.105 mol) of bromine in 50 ml of glacial acetic acid. After 4 hours at 800 C, an addition of 200 ml of H2O is made to the reaction mixture, and the mixture is subsequently cooled. The product which has precipitated out is filtered off with suction, washed with water and dried.

Recrystallisation from dioxane/water yields 15 g (55 /O of theory) of compound IV as a white crystalline powder; m.p. 279--285"C.

Elementary analysis: calculated (for C19H16Br3NeO4) found 28.94% Br 28.4% Br Example 5 2-[B is-(4'-bromophenyl)-amino]-4,6-bis-5"-carboxy-n-pentylamino)-s-triazine (V) 101.3 g (0.2 mol) of 2-diphenylamino-4,6-bis-(5"-carboxy-n-pentylamino)-striazine is brominated analogously to Example 4. Recrystallisation from dioxane/water yields 68 g (51% of theory) of compound V as colourless crystalline powder; m.p. 218--221"C.

Elementary analysis: calculated (for C27H32Br2N6O4) found Br 24.05% Br Example 6 2-[Bis-(4'-bromophenyl)-amino]-4,6-bis-( 11 "-carboxy-n- undecylamino)-s-triazine (VI) 16.3 g (0.025 mol) of 2-diphenylamino-4,6-bis-(11"-carboxy-n-undecylamino)- s-triazine is brominated analogously to Example 3. Recrystallisation from isopropano1/H2O yields 13 g (65% of theory) of compound VI as yellowish crystalline powder; m.p. 135--1400C.

Elementary analysis: calculated (for C39H56Br2NO4) found 19.9% Br 18.9% Br Example 7 2-Diphenylamino-4,6-bis-(2'-chloro-4'-carbethoxyanilino)-s-triazine (VII) Into a solution of 57.4 g (0.1 mol) of 2-diphenylamino-4,6-bis-(4'- carbethoxyanilino)-s-triazine in 500 ml of glacial acetic acid at 300C is introduced 14.2 g (0.2 mol) of chlorine. Water is added to the reaction mixture after 4 hours; the product which has precipitated out is filtered off with suction, and recrystallised from dioxane/water to yield compound VII as colourless crystalline powder; m.p. 196-2000C.

Elementary analysis: calculated (for C33H2BCl2N6O4) found 61.5% C 60.7% C 4.39% H 4.4% H 13.06% N 13.1% N 11.02% Cl 11.5% Cl Example 8 2-Diethylamino-4,6-bis-(2'-bromo-4'-carbethoxyanilino)-s-triazine (VIII) 4.8 g (0.01 mol) of 2-diethylamino-4,6-bis-(4' -carbethoxyanilino)-s-triazine is reacted, analogously to Example 1, with 3.5 g (0.022 mol) of bromine.

Recrystallisation from glacial acetic acid/water yields 4.5 g (70% of theory) of compound VII in the form of colourless crystalline powder; m.p. 196-2000C.

Elementary analysis: calculated (for C25H28Br2N6O4) found 47.18% C 47.2% C 4.43% H 4.4% H 13.21% N 13.3% N 25.12% Br 25.0% Br Example 9 2-[Bis-(4-bromophenyl)-amino] -4,6-bis-(2'-bromo-4'-carboxyanilino)-s- triazine (IX), as well as the K salt (X) and the Ca salt (XI) 44.5 g (0.05 mol) of I is refluxed with 6.4 g (0.1 mol) of 85% KOH in n-butanol for 12 hours. The product which has crystallised out is filtered off with suction, washed with ether and dried to yield 44 g (96% of theory) of compound X in the form of colourless crystalline powder; m.p. > 3300C.

Elementary analysis: calculated (for C29H16Br4K2N6O4) found 8.5%K 8.0%K 20 g (0.0217 mol) of X is dissolved in 500 ml of water and, at elevated temperature, hydrochloric acid (pH 3) is added. The product which has precipitated out is filtered off with suction and dried. There is thus obtained 17.9 g (98% of theory) of compound IX in the form of colourless crystalline powder; m.p.

330"C, acid number calculated=acid number found: 133 mg of KOH/g (for C29H,8Br4N604).

79 g (0.076 mol) of X is dissolved in 1500 ml of water and, at elevated temperature, 16.6 g (0.076 mol) of CaCl2 .6 H2O in 100 ml of H2O is added. The product which has precipitated is filtered off with suction and dried. There is thus obtained 57.6 g (88% of theory) of compound XI in the form of colourless crystalline powder; m.p. 330"C.

Elementary analysis: calculated (for C29H16B r4CaN,O4) found 4.59% Ca 4.47 %Ca Example 10 Polyester from 2-[bis-(4'-bromophenyl)-amino]-4,6-bis- (4"-carbethoxy-2"-bromanilino)-s-triazine (II) and butanediol- 1,4 In a 200 ml glass reactor provided with stirrer, nitrogen inlet and condenser.

8.9 g of compound II, 3.6 g of butanediol-l ,4 and 0.1% of titanium tetraisopropylate (relative to II) are mixed together and melted. In the course of one hour, the reaction mixture is heated under nitrogen in an oil bath, to 2300C and is held at this temperature for a further half hour, in the course of which there is distilled off 98% of the theoretical amount of ethanol. The temperature of the oil bath is then adjusted to 2500 C, and simultaneously a vacuum of 0.2 Torr is carefully applied.

After establishment of this vacuum, condensation is performed for 10 minutes with stirring; nitrogen is then introduced and thepolyester is removed from the reactor.

The relative viscosity of this copolyester is 1.34 and the second order transition temperature is 189"C. The thermogravimetrically determined commencement of decomposition is at 3200 C. The pulverised melt condensate is spread out in a thin layer on the bottom of a Teflon dish ("Teflon" is a registered Trade Mark), and further condensed for 30 hours at 2100C in vacuo (0.5 Torr). The relative viscosity is then 2.53.

Example 11 Polyester fro m 2- from 2-[bis-(4'-bromophenyl)-aminol-4,6-bis-(4"-carbethoxy 2"-bromanilino)-s-triazine (II) and ethylene glycol In a 200 ml glass reactor provided with stirrer, nitrogen inlet and condenser, 8.9 g of compound II, 2.5 g of ethylene glycol and 0.01% of titanium tetraisopropylate (relative to II) are mixed together and melted. In the course of one hour, the reaction mixture is heated under nitrogen, in an oil bath, to 2400C, and maintained for a further one hour at this temperature, in which time there is distilled off 96% of the theoretical amount of ethanol. The temperature of the oil bath is then adjusted to 2800C, and simultaneously a vacuum of 0.2 Torr is carefully applied. After attainment of this vacuum, condensing is performed for 10 minutes with stirring; nitrogen is subsequently introduced, and the polyester is removed from the reactor. The relative viscosity of this copolyester is 1.05. The pulverised melt condensate is spread out in a thin layer on the bottom of a Teflon dish, and is further condensed for 30 hours at 210C in vacuo (0.5 Torr). The relative viscosity is then 1.40, and the second order transition temperature is 215"C.

Example 12 Polyester from 2-[bis-(4'-bromophenyl)amino]-4,6-bis-(4"- carbethoxy-2"-bromanilino)-s-triazine (II), butanediol-l ,4 and dimethylterephthalate (DMT) In a 200 ml glass reactor fitted with stirrer, nitrogen inlet and condenser, 2.67 g of compound If (6 mol %), 9 g of butanediol-1,4, 9.12 g of DMT and 0.01% of titanium tetraisopropylate (relative to II+DMT) are mixed together and melted.

Within one hour, the reaction mixture is heated under nitrogen, in an oil bath, to 2300 C, and held for a further half hour at this temperature, in the course of which there is distilled off 90% of the theoretical amount of methanol and ethanol. The temperature of the oil bath is now adjusted to 250"C, and at the same time a vacuum of 0.3 Torr is carefully applied. After this vacuum has been established, condensing is performed for 10 minutes with stirring; nitrogen is then introduced and the polyester is removed from the reactor. The relative viscosity of this copolyester is 2.05.

Example 13 In a manner analogous to that in Example 12, there is produced a polyester from 6.8 g of DMT, 13.34 g of compound it (30 mol %), 9 g of butanediol-1,4 and 0.01% of titanium tetraisopropylate. The relative viscosity is 1.91, and the second order transition temperature is 1070 C.

Example 14 Polyester from 2-[bis-(4'-bromophenyl)-amino]-4,6-bis-(4"-carbethoxy 2"-bromanilino)-s-triazine (II), 2-diphenylamino-4,6-bis-(p-carbethoxyanilino)-s triazine (A), dimeric acid and butanediol-1,4 In a 200 ml glass reactor provided with stirrer, nitrogen inlet and condenser, 2.22 g of II, 12.64 g of A, 0.3 g of dimeric acid (Empol 1010, Uniliver-Emery "Empol" is a registered Trade Mark), 6.77 g of butanediol-l,4- and 0.01 , of titanium tetraisopropylate (relative to II) are mixed and melted down. In the course of 1 1/2 hours, the reaction mixture is heated under nitrogen, in an oil bath, to 230 C, and held for a further half hour at this temperature, in which time there is distilled off 98% of the theoretical amount of ethanol. The temperature of the oil bath is now adjusted to 2500C, and simultaneously a vacuum of 0.2 Torr is carefully applied. After establishment of this vacuum, the mixture is condensed with stirring for 15 minutes; nitrogen is then introduced and the polyester is removed from the reactor. The relative viscosity of this copolyester is 1.42. and the second order transition temperature is 174 C.

Example 15 Polyester from 2-[bis-(4'-bromophenyl)-aminol-4,6-bis-(4"- carbethoxy-2"-bromanilino)-s-triazine (II) and hexanediol- 1,6 In a 200 ml glass reactor provided with stirrer, nitrogen inlet and condenser, 8.9 g of II, 3.6 g of hexanediol-1,6 and 0.01% of titanium tetraisopropylate (relative to II) are mixed together and melted down. Within one hour, the reaction mixture is heated under nitrogen, in an oil bath, to 240"C, and held at this temperature for a further half hour, in the course of which 90% of the theoretical amount of ethanol distils off. The temperature of the oil bath is then adjusted to 2800 C, and at the same time a vacuum of 0.1 Torr is carefully applied. After establishment of this vacuum, the mixture is condensed for 15 minutes with stirring; nitrogen is subsequently introduced and the polyester is removed from the reactor. The relative viscosity of this copolyester is 1.47, and the second order transition temperature is 1700C. The thermogravimetrically determined commencement of decomposition is at 33O0C. For comparison, the commencement of decomposition of an analogous polyester containing 2-diphenylamino-4,6-bis-(pcarbethoxyanilino)-s-triazine instead of II is at 3380C.

Example 16 Into a 1.5 1 reactor provided with stirrer, nitrogen inlet, condenser and temperature-measuring device are placed 62.6 g of DMT, 58.1 g of butanediol-1,4 and 0.04 g of titanium tetraisopropylate. While the mixture is being stirred and nitrogen introduced, the methanol formed is distilled off for 1 hour at temperatures between 200 and 220"C. There are then added 17.7 g of X, wherein X is as defined in the heading of Example 9, and 6.2 g of Sb2O3 suspended in 30 ml of butanediol i,4; the excess of butanediol-1,4 is distilled off and the temperature of the oil bath is raised to 2500C. A vacuum of 0.15 Torr is established in the course of 45 minutes, and after a further 45 minutes the polyester is removed. The relative viscosity is 2.85. The polyester was injection moulded into the form of standard small bars, and the following properties were determined: relative viscosity: 1.97, combustibility: 30.1% (ASTMD 2863) Example 17 (Polyamide) 6.64 g of V and 2.04 g of dodecamethylenediamine are melted at 2000 C, with stirring and the introduction of nitrogen in a 100 ml glass reactor, and the temperature is then raised step by step in the course of 100 minutes to 2800C. There has then formed a polyamide having a relative viscosity of 1.90. The second order transition temperature is 85"C, and the softening temperature is 155"C.

Example 18 By a procedure analogous to that of Example 14, a polyester from compound II and butanediol- 1,4, in which 2 mol % of the compound II is replaced by dimeric acid, is produced (llrei=1 .78), and is injection moulded into the form of standard small bars, on which the following properties are measured: flexural strength (kp/cm2) (DIN 53 452) 1202 modulus of elasticity from bending test (kp/cm2) 19600 impact strength (cmkp/cm2) without fracture impact strength (notched) (cmkp/cm2) DIN 53 453) 4.46 dimensional stability under heat ("C) (ISO/R 75 RSA) 145 lilrel 1.50 Threads are drawn by hand from a portion of the copolyester. Self-extinction occurred after the threads had been ignited by means of a gas burner.

Examples 19 to 31 By procedures analogous to those of Examples 10-1 5, copolyesters are produced, with the condensation times under vacuum being between 5 and 100 minutes. The respective compositions and the analytical data are given in the Table which follows. The abbreviations used therein are given below: Hy-diae= hydroquinone diacetate BPA-diac= bisphenol-A diacetate t-CHDC= trans-cyclohexanedicarboxylic acid DMAZ= azelaic acid dimethyl ester B 14= butanediol-1,4 1,4 CHDM= cyclohexanedimethanol 1,4 DEG= diethylene glycol EG= ethylene glycol D 22= 2,2-bis-[4'-( -hydroxyethyl)-phenyl]-propane NPG= neopentyl glycol

Example No. Composition Molar ratio libel TG( C) T5( C) 19 V+Hy-diac 0,5,:0,5 1,09 - 135 20 V+BPA-diac 0,5:0,5 1,11 - 135 21 V+t-CHDC+B 14 0,25:0,25:0,5 1,85 42 115 22 V+DMAZ+B 14 0,45:0,05:0,5 1,70 49 120 23 V+succinic acid+B 14 0,45:0,05:0,5 1,63 44 120 24 V+1,4 CHDM 0,5:0,5 1,74 68 145 25 V+EG+D 22 0,5:0,25:0,25 1,53 66 120 26 II+t-CHDC+B 14 0,35:0,15:0,5 1,44 162 205 27 II+DMAZ+B 14 0,45:0,05:0,5 1,36 165 215 28 II+B 14+DEG 0,5:0,35:0.15 1,30 186 155 29 II+B 14:NPG 0,5:0,25:0,25 1,27 192 215 30 III+B 14 0,5:0,5 1,16 - 300* 31 DMT+III+B 14 0,45:0,05:0,5 1,70 56 206* *crystalline melting point (DTA) T=glaSS transition temperature Ts=softening temperature WHAT WE CLAIM IS: 1. A halogen-containing heterocyclic dicarboxylic acid of the general formula

wherein R' represents alkylene or cycloalkylene having 1 to 17 C atoms, phenylene.

benzylene, or a halogenated phenylene or benzylene radical of the formulae

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (46)

**WARNING** start of CLMS field may overlap end of DESC **. Threads are drawn by hand from a portion of the copolyester. Self-extinction occurred after the threads had been ignited by means of a gas burner. Examples 19 to 31 By procedures analogous to those of Examples 10-1 5, copolyesters are produced, with the condensation times under vacuum being between 5 and 100 minutes. The respective compositions and the analytical data are given in the Table which follows. The abbreviations used therein are given below: Hy-diae= hydroquinone diacetate BPA-diac= bisphenol-A diacetate t-CHDC= trans-cyclohexanedicarboxylic acid DMAZ= azelaic acid dimethyl ester B 14= butanediol-1,4 1,4 CHDM= cyclohexanedimethanol 1,4 DEG= diethylene glycol EG= ethylene glycol D 22= 2,2-bis-[4'-(ss-hydroxyethyl)-phenyl]-propane NPG= neopentyl glycol Example No. Composition Molar ratio libel TG( C) T5( C) 19 V+Hy-diac 0,5,:0,5 1,09 - 135 20 V+BPA-diac 0,5:0,5 1,11 - 135 21 V+t-CHDC+B 14 0,25:0,25:0,5 1,85 42 115 22 V+DMAZ+B 14 0,45:0,05:0,5 1,70 49 120 23 V+succinic acid+B 14 0,45:0,05:0,5 1,63 44 120 24 V+1,4 CHDM 0,5:0,5 1,74 68 145 25 V+EG+D 22 0,5:0,25:0,25 1,53 66 120 26 II+t-CHDC+B 14 0,35:0,15:0,5 1,44 162 205 27 II+DMAZ+B 14 0,45:0,05:0,5 1,36 165 215 28 II+B 14+DEG 0,5:0,35:0.15 1,30 186 155 29 II+B 14:NPG 0,5:0,25:0,25 1,27 192 215 30 III+B 14 0,5:0,5 1,16 - 300* 31 DMT+III+B 14 0,45:0,05:0,5 1,70 56 206* *crystalline melting point (DTA) T=glaSS transition temperature Ts=softening temperature WHAT WE CLAIM IS:

1. A halogen-containing heterocyclic dicarboxylic acid of the general formula

wherein R' represents alkylene or cycloalkylene having 1 to 17 C atoms, phenylene.

benzylene, or a halogenated phenylene or benzylene radical of the formulae

respectively, in which X represents chlorine or bromine atoms, and n represents an integer from 1 to 4, R2, R3 and R4 are identical or different and represent a hydrogen atom, alkyl or cycloalkyl each having 1 to 18 C atoms, phenyl, benzyl, halogenated phenyl and benzyl of the formulae

respectively, in which m represents integers from I to 5, and X has the aforesaid meaning, with at least one of the radicals R1 to R4 representing one of the halogencontaining groups; and the acid halides, acid esters, acid amides and salts thereof.

2. A dicarboxylic acid according to Claim 1, wherein n represents 2 and represents 1--3.

3. A dicarboxylic acid according to claim 1 wherein n represents 1 and m is I or 2.

4. A dicarboxylic acid according to any of the preceding claims, wherein X represents a bromine atom.

5. A dicarboxylic acid according to any of the preceding claims, wherein R' as alkylene contains 1-12 C atoms, and as cycloalkylene it contains the ring carbon atoms, and the -CH2- group in the benzylene group is bonded in the pposition with respect to the carboxyl group.

6. A dicarboxylic acid according to claim 5 wherein R' as alkylene contains 3-10 C atoms and as cycloalkylene contains 6 ring carbon atoms.

7. A dicarboxylic acid according to any of the preceding claims, wherein R2 represents phenyl, halogenated phenyl or a hydrogen atom.

8. A dicarboxylic acid according to any of the preceding claims, wherein R3 and R4 are identical or different and each represents a hydrogen atom, alkyl having 1 to 12 C atoms, phenyl or halogenated phenyl.

9. A dicarboxylic acid according to claim 8 wherein R3 and R4 each represent alkyl having 1 to 4 carbon atoms.

10. A dicarboxylic acid according to any of the preceding claims, wherein R', R3 and R4 represent halogen-containing groups.

11. 2 - [Bis - (4 - bromophenyl) - amino] - 4,5 - bis - (4 - carboxyanilino) s - triazine or 2 - [bis - (4 - bromophenyl) - amino] - 4,6 - bis - (2 - bromo - 4 carboxyanilino) - s - triazine.

12. A dicarboxylic acid according to any of claims 1 to 10, which as acid halide contains bromine or chlorine atoms as halogen; as acid ester or acid amide contains alkyl, cycloalkyl, benzyl or phenyl in the ester group or amide group; and as salt it is a metal salt or ammonium salt.

13. A dicarboxylic acid of formula I as claimed in claim 1 substantially as described with reference to any of Examples I to 9.

14. A process for producing a halogen-containing heterocyclic dicarboxylic acid of the general formula I according to claim 1, in which process a) a compound of the formula II

wherein R' to R4 represent the halogen-free radicals of the dicarboxylic acids of the formula I, with at least one of the radicals R' to R4 representing phenyl, benzyl or phenylene or benzylene, or partially brominated and/or chlorinated radicals derived therefrom, and R5 being halogen, hydroxyl, an alcohol radical or amino radical, or the group MO- wherein M represents a cation, is brominated and/or chlorinated; or b) 1 mol of dichloro-s-triazine amino-substituted with the R3R4N group is reacted with 2 mols of amino acid or amino acid ester of the formula

or 1 mol of monochloro-s-triazine disubstituted with the

group is reacted with 1 mol of amine of the formula R3R4NH, wherein the radicals R' to R5 are as defined in claim 1, and at least one of the radicals R' to R4 represents a halogen-containing group.

15. A process for producing a dicarboxylic acid according to claim 14 substantially as described with reference to

16. A dicarboxylic acid of formula I when produced by a process claimed in claim 14 or 15.

17. A method of flameproofing a thermoplastic polymer by incorporating into the polymer, as flameProofing agent, a dicarboxylic acid of formula I, or a derivative thereof, as claimed in any of claims 1 to 13 and 16.

18. A method of internally flameproofing a polyester or polyamide by incorporating into the polymer chain during manufacture, as internal flameproofing agent, a dicarboxylic acid of formula I, or a derivative thereof, as claimed in any of claims 1 to 13 and 16.

19. A method as claimed in claim 17 or 18 substantially as described with reference to any of Examples 10 to 31.

20. A halogen-containing thermoplastic polyester or polyamide of which the dicarboxylic acid constituent consists, partly or completely, of a dicarboxylic acid of formula I as claimed in any of claims I to 13 and 16.

21. A polyester according to claim 20 which is formed from aliphatic cycloaliphatic and/or aromatic dicarboxylic acids, hydroxycarboxylic acids and dlols.

22. A polyamide according to claim 20 which is formed from aliphatic, cycloaliphatic and/or aromatic dicarboxylic acids, aminocarboxylic acids and diamines.

23. A polyamide according to claim 22 wherein the diamines contain 6 to 14 C atoms.

24. A polyamide according to claim 23 wherein the diamines contain 6 to 14 C atoms.

25. A polyester according to claim 20 or 21 which contains, in addition to the dicarboxylic acid of formula I, terephthalic acid, isophthalic acid, 1,4-cyclohexane- dicarboxylic acid and/or an aliphatic dicarboxylic acid having 2 to 36 C atoms.

26. A polyester according to claim 25 wherein the aliphatic dicarboxylic acid has 6 to 36 C atoms.

27. A polyester according to claim 21 which contains, as diol, a linear alkylenediol having 2 to 12 C atoms, 1,4-cyclohexanediol, 1,4-dihydroxy cyclohexane and/or N,N-heterocyclic diols.

28. A polyester according to claim 27 wherein the linear alkylenediol has 2 to 6 C atoms.

29. A polyester according to any of claims 20,21 and 25 to 28, having a relative viscosity of 1.3 to 4.0, measured as a solution of Ig of polyester in 100 ml. of a solvent consisting of equal parts of phenol and symmetrical tetrachloroethane, at 30 C.

30. A polyester according to any of claims 20, 21 and 25 to 29, wherein the content of dicarboxylic acid of formula I is 0.5 to 50 mol.%, relative to the polyester.

31. A polyester according to claim 30 wherein the content of dicarboxylic acid of formula I Is 30 to 50 mol %, relative to the polyester.

32. A polyester according to claim 31 wherein the content of dicarboxylic acid of formula lis 40 to 50 mol %, relative to the polyester.

33. A polyester according to any of claims 20, 21 and 25 to 32 wherein the content of the dicarboxylic acid of formula I is I to 15 mol %, relative to the polyester.

34. A polyester according to claim 33 wherein the content of the dicarboxylic acid of formula I is 2 to 8 mol. %, relative to the polyester.

35. A polyester according to any of claims 20, 21 and 25 to 34 having a glass transition temperature (Tg) of at least 1000C.

36. A polyester according to claim 30 which has a content of dicarboxylic acid of formula I of 0.5 to 8 mo. % and which also contains at least 30 mol. % of terephthalic acid and/or isophthalic acid and, as diol, linear alkylenediols having 2 to 4 C atoms, 1,4-cyclohexanediol or 1 ,4-dihydroxymethylene cyclohexane.

37. A polyester according to claim 36 wherein the content of dicarboxylic acid of formlula I is 1 to 5 mol %.

38. A halogen-containing thermoplastic polyester or polyamide as claimed in claim 20 substantially as described with reference to any of Examples 10 to 31.

39. A process of producing a halogen containing thermoplastic polyester or polyamide as claimed in claim 20, wherein the dicarboxylic acid, concomitantly incorporated by condensation, is partly or completely a dicarboxylic acid of formula I, or a polyester-forming or polyamide-forming derivative thereof, as claimed in claim 1.

40. A process as claimed in claim 39 substantially as described with reference to any of Examples 10 to 31.

41. A halogen-containing thermoplastic polyester or polyamide when produced by a process claimed in claim 39 or 40.

42. A method of producing a shaped article comprising injection-moulding or extruding a polyester as claimed in any of claims 20, 21, 25 to 38 and 41.

43. A method as clainied in claim 42 wherein the shaped articles are fibres.

44. A method of producing a shaped article as claimed in claim 42 or 43 substantially as described with reference to Example 16 or 18.

45. A polyester shaped article when produced by a method claimed in any of claims 42 to 44.

46. Polyester fibres when produced by a method claimed in any of claims 42 to 44.