FR2470780A1 - Thio phenylene di:carboxy oligomers - can be co:polycondensed with polyester(s) to improve rigidity and solvent resistance - Google Patents

Abstract

Novel oligomers are of formula (I) (where Z is hydrocarbyloxy or w-hydroxyalkylamino and n is 0-20). Also claimed are the intermediate prods. for prepg. (I) and in which Z is replaced by H. (I) can be incorporated in the molecules of polycondensates to improve their rigidity and solvent resistance. Pref. in (I) Z is 1-6C alkoxy, 6-10C aryloxy or HO-(CR2R3)q-NH- where q is 2 or 3, R2 and R3 are H or 1-3C alkoxyl and n is 2,4 or 6.

Description

 Phenylene polysulfide is a polymer characterized by high insolubility in various solvents and good chemical inertness which imparts good high temperature resistance in an aggressive environment. Furthermore, it is prepared from inexpensive starting materials (p-dichlorobenzene and sodium sulphide) by simple methods (French Patent Application No. 2,312,523, 2,312,524 and 2,312,525).

 however, these methods do not lead to high molecular weight, and therefore the conditions of use, which involve crosslinking, are not suitable for all applications.

 The object of the present invention is to describe novel thio-p-phenylene-dicarboxy-telechelic oligo-mers which can be incorporated into conventional polycondensates and to improve properties by virtue of the rigidity of the polysulfide linkages.

 In the field of polycondensates, we are witnessing an evolution of techniques with the development of polymers containing rigid segments that orient in solution when the concentration reaches a limit value.

 The orientation phenomenon in solution has a certain number of advantages, in particular for the use of polymers by spinning.

 The orientation of polycondensates in solution with the formation of anisotropic solutions has been observed in the case of totally aromatic polyamides and in the case of butanediol polyesters and paraterphensyl diacid.

It has been found within the scope of the invention that parathiophenylene oligomers can be functionalized at a-4 and e-4 and that it is possible to incorporate these rigid segments into polycondensates, and in particular into polyesters. as well as preparing honopolyesters from these oligomers. The compounds which are the subject of the invention correspond to the following general formula

In this formula I, Z is in general a # -hydroxyalkylamino or hydrocarbyloxy group; the latter contain, for example, from 1 to 12 carbon atoms. The group Z is chosen from the following: 1) an alkoxy group, R 10 in which R 1 is an alkyl group of 3 6
carbon atoms, linear or branched, but preferably the substituent
methyl or ethyl; These products will be designated later by Ia.

2) an aryloxy group, ArO, in which Ar represents an aryl group
having from 6 to 10 carbon atoms and preferably the phenyl group;
these products will be designated subsequently by Ib 3) A # -hydroxy-alkyl-amino group HO- (CR 2 R 3) q-NH- in which q is a
an integer equal to 2 or 3, preferably 2, R2 and R3 are
hydrogen atoms or alkyl groups having 1 to 3 carbon atoms
carbon; preferably, R2 and R3 are hydrogen atoms;
the products will be designated later by Ic.

 In the formula I, n is an integer of 0 to 20, preferably 2, 4 or 6. It is not excluded that, in the case of preparation methods leading to a mixture of compounds I, n can take a statistical value different from an integer; it can then take all values between 0 and 20.

The preparation of the compounds of the formula I is generally carried out by the synthesis of dihalo-telechelic compounds of the general formula II or dimercapto-telechelics of the general formula III.

 In formula II, X may be a halogen, preferably a chlorine or bromine atom, and ml is a number which may take the same values as those referred to for formula I, or the n value. -2.

 In formula III, M is an alkali metal and m2 may take zero or any positive value equal to n - 2.

The compounds of formula II or m1b 2 may be obtained by condensation of a dihalogeno-diphenylsulphide II (m1 = 0) with an alkali metal sulphide, for example sodium sulphide, according to the following equation

 Depending on the ratio y / x, it is possible to obtain various types of compounds II for which m1 takes the values described above.

It is also possible, to obtain the compounds II, to use the reaction of dihalo-diphenylsulphide IIm1 = O dimercapto-4,4'-diphenylsulfide in the presence of an acid acceptor, for example sodium carbonate or sodium carbonate. potassium, sodium hydride, etc. The acid acceptor is preferably used in stoichiometric proportions or in slight excess.

 Depending on the ratio y / x, it is possible to obtain various types of compounds II for which m1 can take the values described above.

 From the compounds of type II, it is possible, without departing from the scope of the invention, to introduce the carboxylic groups according to two processes.

ou Y = COOM ou CN. Là aussi, on peut partir des acides correspondants, en présence d'accepteur basique du type de ceux utilisés pour la préparation des composés II. In the first case, the compounds II are condensed on an alkali metal salt of p-mercapto-benzoic acid or p-mercapto-benzonitrile according to eq. 3 next

or Y = COOM or CN. Here too, it is possible to start from the corresponding acids in the presence of a basic acceptor of the type used for the preparation of compounds II.

 This process allows the introduction of two additional phenuylenes and then compounds IV are obtained in which Y is either an alkaline carboxylate group (IVa) or a nitrile group (IVb), and n can take all the values described for compound I, (n = ml + 2).

In the second case, the condensation of cuprous cyanide known in the prior art is used to convert compounds II into IVb compounds for which Y is then a nitrile group. This process leads to compounds
IVb having a number of phenylenic groups identical to that of II, (n = ml),
Compounds IVb can also be obtained by the reaction of a p-halogenobenzonitrile on dimercapto-telechelic compounds III, according to

<tb> the following <SEP> equation <SEP>:
<tb> 2 <SEP> CN <SEP> e <SEP> X <SEP> + <SEP> MSOSOSSMCNOSOSCN
<tb><SEP> III <SEP> IVb <SEP> eq. <SEP> 4
<Tb>
In this equation, X is a halogen, preferably a chlorine or bromine atom, and n takes the values described in the case of I, (n = m2 + 2).

 Transformation of intermediates IVa and IVb into compounds I is carried out by all the known methods for converting the carboxylic acid or nitrile group to the ester group: esterification when Z is a hydrocarbyloxy group and starting from IVa or the acid corresponding, condensation of an alcohol in acidic medium when Z is an alkoxy group and that is used IVb, condensation of an e, s-amino-alcohol when Z is an s-hydroxy-alkyl-amino group and that starting from IVb, or any other method described in the prior art for this type of conversion. Intermediate can be passed by other compounds, derived in a manner known per se from the above, and having an equivalent behavior, for example an acid halide or an anhydride of the acid of formula IVa (with Y = COOH). All intermediate compounds, in particular those of formula IVa with Y = COOR are also part of the invention.

 The preparation methods indicated in this patent are preferred examples of usable techniques, but it is clear that any known method for the preparation of aromatic compounds having terminal groups identical to those of formula I can be used.

 The dicarboxy-telechelic oligomers of the invention can be used to obtain rigid polycondensates.

In the case of the polyesters, the compounds Ia and Ib can be polycondensed with one or more diols under the conventional polycondensation conditions, advantageously using an excess of the diol (s), providing an exchanging step with removal of light alcohol. , in the case where Z is an alkoxy or phenol group in the case where Z is a phenoxy group, followed by a polycondensation step.

 In these formulas, R4 is a radical or a mixture of bivalent radicals comprising from 2 to 10 carbon atoms, linear or branched, and / or a divalent radical of the family of polyethyleneglycol with a number-average molecular mass, preferably between 100 and 300; n has the values described for compound I and m all known values for polyesters.

 The above polycondensation reaction can also be carried out with, as the starting diester, a mixture of at least one compound Ia with at least one dicarboxylic acid diester conventionally used in polycondensation, for example methyl terephthalate. or methyl isophthalate.

 The above polycondensation reaction may also be carried out with as starting diester at least one aromatic dicarboxylic acid diester conventionally used in polycondensation, for example methyl terephthalate or methyl isophthalate, and as diol a mixture an aliphatic diol HOR40II and a compound of type Ic.

avec formation d'un copolyester segmenté de formule VIa. It is also possible, without departing from the scope of the invention, to react the compounds Ia on a high mass polyester at high temperature.

with formation of a segmented copolyester of formula VIa.

In these formulas, R4 and m can take the values described for the products of lteq. 5, and o and p are the typical values of segment polycondensates. If the compounds Ic are used, the formation of amide copolyester of the general formula VIb has been observed.

 In these formulas R4 and m take the values described for the products of the eq. 5; R2R3, q, n the values described for the products Ic and o and p the classical values of the segmented copolycondensates.

 The segmented polycondensates of the present invention have properties which depend on the amount of thioparaphenylene rigid segments introduced into the copolyester and the length of these segments.

 In general, however, when the average value of n in formula I is at least 9, a second brewing temperature, higher than that of the unmodified homopolyester, appears.

 In addition, the solvent resistance is improved over the polyesters and copolyesters of the prior art.

 The following examples illustrate the invention without, however, limiting its scope.

Examples 1 to 14.

Preparation of thioparaphenylene oligomers

The oligomers will be denoted by the numbers corresponding to the general formula assigned an index equal to the number of phenyl nuclei of the molecule.

The yields and characteristics are reported in Table II.

Example I: Preparation of compound 114
In a 500 ml reactor, 48 g (0.2 mol) of sodium sulphide and 200 ml of N-methyl-2-pyrrolidone are charged with nitrogen sweeping. The mixture is dehydrated by heating at 140 ° C. and then refluxing the solvent. 172 g (0.5 mole) of bis- (p-bromophenyl) sulfide and 200 ml of N-methyl-2-pyrrolidone are then added. The mixture is heated for 3 hours at 120 ° C.

The product is washed with water, alcohol, chloroform and recrystallized from toluene.

Example 2 Preparation of Compound 116
In a 500 ml reactor, 12.5 g (0.05 mol) of bis (mercaptophenyl) sulphide and 200 ml of N-methyl-2-pyrrolidone are added. The equipment is degassed and swept with nitrogen. 13.8 g (0.1 mol) of potassium carbonate and 68.8 g (0.2 mol) of bis- (p-bromophenyl) sulphide dissolved in 100 μl of N-methyl-2-pyrrolidone are then added. .

The mixture is heated for 3 hours at 150 ° C.

The product is then washed with water, with alcohol and then with chloroform and recrystallized in xylene.

Example 3 Preparation of Compound II with an Average Number of Phenyl Nuclei
between 9 and 14.

In a 500 ml reactor, 48 g (0.2 mol) of sodium sulphide and 200 ml of N-methyl-2-pyrrolidone are charged with nitrogen sweeping. The mixture is dehydrated by heating to 140 ° C. and then refluxing the solvent. 68.8 g and 75.8 g (0.2 to 0.22 moles) of bis- (p-bromophenyl) sulphide dissolved in 200 ml of N-methyl-2-pyrrolidone are then added.

It is heated for 3 hours at 20 ° C. The product is washed 4 times with water, once with alcohol, dried and then extracted with hot xylene. Depending on the proportion of the reactants, a product is obtained comprising on average between 9 and 14 phenyl rings.

Example 4 Preparation of Compound Ia4 from Compound II2
In a 500 ml reactor, 12.3 g (0.04 mol) of p-mercapto-benzoic acid and 200 ml of N-methyl-2-pyrrolidone are added. The equipment is degassed and swept with nitrogen. 11.04 g (0.08 mol) of potassium carbonate are added and the mixture is heated to 800 ° C. 6.76 g (0.02 mol) of bis (p-bromophenyl) sulphide dissolved in 100 ml of N-methyl-2-pyrrolidone are then added.

The reaction mixture is heated for 3 hours at 150 ° C. The reactor is allowed to cool and when the temperature does not exceed 800 ° C., 10 ml (0.16 mol) of methyl iodide are added, the duration of addition being 2 hours. to heat for another 3 hours at 800C.

The solvent is then evaporated under vacuum, the product is washed 3 times with water, once with alcohol and recrystallized in chloroform.

EXAMPLE 5 Preparation of Ian compounds (n = 4.6 and 11) from the compounds
II4, II6 and IIn (n # 9).

The p-mercaptobenzoic acid is reacted with the compound II having the necessary number of phenyl in the molar proportions and in the same manner as in Example 4. For the compounds having 8 or more phenyl rings, S is used instead of methyl iodide methyl tosylate (TsOCH3) and the temperature of the second stage is raised to 150 C.

The conditions are summarized in Table I.

<SEP> Compound <SEP><SEP><SEP><SEP> SEP <SEP> Agent <SEP> Ester <SEP> Agent Purification
<tb><SEP> Recrystallization
<tb><SEP> II4 <SEP> 150 C <SEP> then <SEP> 80 C <SEP> CH3I <SEP> in <SEP> the <SEP> chloro
<tb><SEP> form
<tb><SEP> Recrystallization
<tb><SEP> II6 <SEP> 180 C <SEP> then <SEP> 80 C <SEP> CH3I
<tb> in <SEP> the <SEP> xylene
<tb><SEP> Extraction <SEP> at
<tb><SEP> II8 <SEP> 200 C <SEP> then <SEP> 150 C <SEP> TsOCH3
<tb> toluene <SEP> hot
<tb>"
<tb><SEP> IIn <SEP> n <SEP>#<SEP> 11 <SEP><SEP> 200 C <SEP> Then <SEP> 150 C <SEP> TsOCH3
<Tb>

Example 6 Preparation of IVan Compounds (n = 4, 6, 8, or # 11)
The procedure and treatment are the same as those described in Examples 4 and 5, omitting the esterification step.

Example 1: Preparation of compounds Ibn (n = 4, 6, 8 or # 11) from
compounds IVa.

Compounds IVa are esterified using phenyl phosphite in pyridine as described in the prior art.

Example 8: Preparation of compound IVb4 from compound II4

In a 250 ml reactor, 28 g (0.05 mole) of compound II4, 17.9 g (0.2 mole) of cuprous cyanide and 150 ml of N-methyl-2-pyrrolidone are added. It is heated for 3 hours at 200 ° C. The cooled reaction mixture is poured into a solution composed of 350 ml of ferric chloride solution (d = 1.26) and 100 ml of concentrated hydrochloric acid. It is left to react for 30 minutes S 60 C.

The product is filtered, washed with water, dissolved in chloroform; the organic phase is washed with water, dried and the solvent evaporated. The product is recrystallized from acetic acid.

Example 9: Preparation of IVbn compounds (n = 6 or 9) from compounds II.

250 g of a compound containing the desired number of phenyls, 20 g of N, N-dimethylbenzanide and 10 g (0.11 mol) of cuprous cyanide are placed in a 250 ml reactor. It is heated for 3 h at 2300C. The cooled reaction mixture is poured into a solution of 350 ml of ferric chloride solution (d = 1.26) and 100 ml of concentrated hydrochloric acid. Allowed to react for 1 hour at 600C.

The product is filtered, washed with water until the yellow color disappears, washed with methanol and then extracted continuously with hot methanol.

Example 10: Another preparation of compound IVb4
In a 500 ml reactor, 25 g (0.1 mol) of bis (p-mercaptophenyl) sulfide and 200 ml of N, N-dimethylformamide are added. The equipment is degassed and swept with nitrogen. 27.6 g (0.2 mol) of potassium carbonate are added, the mixture is heated to 60 ° C. and then 36.4 g (0.2 mol) of p-bromobenzonitrile dissolved in 100 ml of N, N-dimethylformamide are added. .

It is heated for 3 hours at 100.degree.

The solvent is evaporated under vacuum, the product is dissolved in chloroform, the organic solution is washed, dried and the solvent evaporated; the product is recrystallized from acetic acid.

Example 11: Another preparation of compound IVb6
The preparation is identical to that described in Example 10 but the p-bromobenzonitrile is replaced by 58 g (0.2 mole) of (p-cyano-p-bromophenyl) sulfide.

Example 12 Preparation of Icn compounds (n - 2, 4, 6 or # 9) from
IVb compounds
250 g of compound IVb, 200 ml of ethanolamine and 200 mg of crystallized cadmium acetate are placed in a 250 ml reactor. The mixture is heated for 3 hours 16500. The cooled reaction mixture is poured into 1 liter of water, the product is filtered, washed twice with water, twice with alcohol and dried under vacuum.

Example 13 Preparation of Compounds Ia from Ic Compounds

In a 50 ml reactor, 5 g of compound Ic, 40 ml of methanol and 1 g of phosphoric acid are added. Heating at 1800C for 24 hours, the pressure rises to 40 bar. The reactor is cooled and decompressed. The product is washed with methanol or recrystallized if it comprises from 2 to 6 phenyl rings.

Example 14 Preparation of compounds Ia from compounds IVb.

In a 500 ml reactor, 20 g of compound IVbn and 300 ml of an alcohol (methanol for n = 2, methoxy-2-ethanol for n = 4, 6) are placed. The solution is saturated with gaseous hydrochloric acid and then gradually heated up to the vicinity of the reflux until complete disappearance of the nitrile bands by infrared spectrometry.

The solvent is evaporated under vacuum and the product recrystallized.

Characteristics of the products and yields of the reactions described in Examples 1 to 14.

Groups
<tb> Example <SEP> Product <SEP> Nb <SEP> of <SEP> phenyl <SEP> Yield <SEP><SEP> Point of <SEP> merge
<tb><SEP> terminals
<tb><SEP> 1 <SEP> II4 <SEP> Br <SEP> 4 <SEP> 40 <SEP>% <SEP> 172
<tb> 2 <SEP> II6 <SEP> Br <SEP> 6 <SEP> 75 <SEP>% <SEP> 210
<tb><SEP> 3 <SEP> IIn <SEP> Br <SEP> stat. <SEP>#<SEP> 9 <SEP> 80 <SEP>% <SEP> 260-275
<tb> 4 <SEP> Ia4 <SEP> CO2CH3 <SEP> 4 <SEP> 5-10 <SEP>% <SEP> 200
<tb><SEP> 5 <SEP> Ia6 <SEP> C 2CH3 <SEP> 6 <SEP> 30 <SEP>% <SEP> 230
<tb><SEP> - <SEP> Ia8 <SEP> C02CH3 <SEP> 8 <SEP> 50 <SEP> Z <SEP> 250
<tb><SEP> - <SEP> Ian <SEP> CO2CH3 <SEP> stat <SEP>#<SEP> 11 <SEP> 90 <SEP>% <SEP> 260-270
<tb><SEP> 6 <SEP> IVan <SEP> CO2CH3 <SEP> stat. <SEP>#<SEP> 11 <SEP> 90 <SEP>% <SEP> 260-270
<tb><SEP> 7 <SEP> Ibn <SEP> C02C6H5 <SEP> stat. <SEP>#<SEP> 11 <SEP> 95 <SEP>% <SEP> 260-270
<tb> 8 <SEP> IVb4 <SEP> CN <SEP> 4 <SEP> 90 <SEP><SEP> Z <SEP> 205
<tb><SEP> 9 <SEP> IVbn <SEP> CN <SEP> stat. <SEP>#<SEP> 9 <SEP> 95 <SEP>% <SEP> 250-270
<tb><SEP> 10 <SEP> IVb4 <SEP> CN <SEP> 4 <SEP> 80 <SEP>% <SEP> 17 #
<tb><SEP> 11 <SEP> IVb6 <SEP> CN <SEP> 6 <SEP> 85 <SE> Z <SEP> 208
<tb><SEP> 12 <SEP> Ic2 <SEP> CONHCH2CH2OH <SEP> 2 <SEP> 95 <SEP>% <SEP> 219
<tb><SEP> - <SEP> Ic4 <SEP>"<SEP> 4 <SEP> 95 <SEP>% <SEP> 264
###
<tb> - <SEP> Ic8 <SEP>"<SEP> 8 <SEP> 95 <SEP>% <SEP> 265-275
<tb><SEP> - <SEP> I ~~ <SEP>"<SEP> stat. <SEP> a <SEP> 9 <SEP> 95 <SEP>% <SEP> 265-275
<tb><SEP> 13 <SEP> Ian <SEP> CO2CH3 <SEP> stat. <SEP> a <SEP> 9 <SEP> 95 <SEP>% <SEP> 260-270
<tb><SEP> 14 <SEP> Ia2 <SEP> CO2CH3 <SEP> 2 <SEP> 95 <SEP>% <SEP> 124.5
<tb><SEP> - <SEP> Ia4 <SEP> CO2CH2CH2OCH3 <SEP> 4 <SEP> 95 <SEP>%
<tb><SEP> - <SEP> Ia6 <SEP>"<SEP> 6 <SEP> 95 <SEP>%
<Tb>
Example 15 Copolycondensation of an oligothiophenylene dicarbomethoxy-parchment
1a4 with methyl isophthalate and butanediol.

In a polycondensation reactor, 2.75 g (0.005 mole) of compound Ia4, 7.75 g (0.04 mole) of methyl isophthalate, 8 ml (0.08 mole) of butanediol-1,4 are added. and 30 mg of butyl titanate. Transesterification and polycondensation are conducted under the usual conditions.

11 g of product having a viscosity of 1.05 dl / g (in o-chlorophenol at 30 ° C.) and 2 melting points in differential thermal analysis are obtained.

Example 16 Copolycondensation of Oligothiophenylenebis (Hydroxyethylamide)
telechelic, Ic4 with methyl terephthalate and butanediol.

1.2 g (0.0025 mol) of compound I 4.9 g (0.05 mol) of methyl terephthalate, 9 ml (0.09 mol) of butanediol-1 are placed in a polycondensation reactor. 4 and 25 mg of butyl titanate. Transesterification and polycondensation are conducted under the usual conditions.

12 g of product having a viscosity of 0.7 dl / g (in o-chlorophenol at 30 ° C.) and 2 melting points in differential thermal analysis are obtained.

Example 17 Modification of Polyisophthalate of Butanediol by an Oligothio
phenylene-bis (hydroxyethylamide) -telechelic Ic13.4
In a polycondensation reactor are placed 1.1 g of compound Ic13.4, 10 g of polybutanediol-1,4-isophthalate separately prepared and 20 mg of butyl titanate.

The mixture is heated to 270 ° C. and the pressure is gradually lowered to 0.1 torr. These conditions are maintained for 1 hour. 11 g of product are obtained, not soluble in o-chlorophenol and having 2 melting points in differential thermal analysis.

Example 18 Preparation of a homopolyester from 4,4'-dicarbomethoxy
diphenyl sulfide Ia2 and butanediol.

In a polycondensation reactor, 9.06 g (0.03 mol) of bis (p-carbomethoxyphenyl) sulphide (compound Ia2), 5.4 g (0.06 mol) of butanediol-1,4 and 20 mg are added. butyl titanate. Transesterification and polycondensation are conducted under the usual conditions.

9.7 g of product having a viscosity of 0.8 dl / g (in 1-chlorophenol at 300 ° C.) are obtained.

Example 19 Preparation of a homopolyester of oligothiophenylene dicarbo
methoxy-telechelic Ia4 and tetraethylene glycol.

In a polycondensation reactor are placed 10.36 g (0.02 mole) of compound Ia4, 3.88 g (0.02 mole) of tetraethylene glycol, 1.24 g (0.02 mole) of ethylene glycol and 20 mg of butyl titanate. Transesterification and polycondensation are conducted under the usual conditions.

12.6 g of product having a viscosity of 0.7 dl / g (in ochlorophenol at 30 ° C.) are obtained.

Claims (11)

claims 1. New oligomers of general formula

 n is a number from 0 to 20.  wherein Z is hydrocarbyloxy or w-hydroxyalkylamino and 2. New oligomers according to the general formula of rev. 1, in which  Z is an alkoxy group having 1 to 6 carbon atoms, an aryloxy group  having from 6 to 10 carbon atoms or a w-hydroxyalkylamino group  HO (-CR2R3) q -NH- # where q is 2 or 3, R2 and R3 are hydrogen atoms  or alkyl groups of 1 to 3 carbon atoms and n is 2,4 or 6. 3. Process for the preparation of an oligomer corresponding to the general formula of  claim 1 wherein Z is a hydrocarbyloxy or w-hydro group  xyalkylamino, characterized in that an alcohol is reacted a phenol or  an e, w-amino alcohol on an intermediate compound of formula

 wherein Y is a -COOR group, or an equivalent reactive group. 4. Process according to the rev. 3, in which the equivalent group is a group  ester. 5. Process according to the rev. 3 or 4, wherein, to prepare an inter compound  intermediate of formula IV where Y = COOH or CN, the acid .p-mercapto is reacted  henzoic acid or p-mercaptobenzonitrile on a compound. Formula

 where ml is an integer from I to 20-or is zero and X is halogen. 6. Process according to the rev. 3 or 4, wherein to prepare an intermediate compound  diary of formula IV where Y = CN, a p-halobenzonitrile is reacted with  a compound of formula

 where m2 is zero or any positive value equal to n - 2. 7. As an intermediate in the preparation of oligomers according to  one of claims 1 and 2, an oligomer corresponding to the formula

 wherein Y represents a -COOH group and n is a number from 0 to 20. 8. Use of an oligomer according to claim 1 for the manufacture  of a polycondensate, which comprises reacting this oligomer with  Z is a hydrocarbyloxy group with an alkanediol or a polyalkyl  glycol.  The use of an oligomer according to claim 1, wherein Z is a  w-hydroxya Icoylamino group, for the preparation of a polycondensate by  reacting this oligomer, alone or with at least one alkanediol,  with an aromatic dicarboxylic compound. 10. Use according to claim 8, in which one operates in the presence  addition of an aromatic dicarboxylic compound, so as to form  a copolycondensate. 11. Use of an oligomer according to claim 1 for the manufacture  of a copolycondensate, which comprises reacting this oligomer  with a polyester already formed between an aromatic dicarboxylic compound  and an alkanediol or a polyalkylene glycol.