Abstract: A copolymer consisting essentially of a repeating sequence represented by the formula ##STR1## where Ar.sub.1, Ar.sub.2, and Ar.sub.3, are each independently chosen from the group consisting of ##STR2## which are either unsubstituted or are substituted with one or more substituents chosen from the group consisting of alkyl groups having 1-6 carbon atoms, halogen (F, Cl or Br), and phenyl; Z, Y.sub.1 and Y.sub.2 are each independently O, NH, or S; n and m are positive integers; and X is a covalent bond, O, S, SO.sub.2, CO, C(C.sub.6 H.sub.5).sub.2, C(C.sub.6 H.sub.5)H, C(C.sub.6 H.sub.5)(CH.sub.3), C(CH.sub.3).sub.2, C(CH.sub.3)H, CH.sub.2, C(CF.sub.3).sub.2, or 3,3,5-trimethyl cyclohexyl. The polymers of this invention are derived from a minimum of three different monomers.

Abstract: Crosslinkable, polyaromatic, polyether or polyester oligomers can have glass transition temperatures above 900.degree. F. while exhibiting desirable toughness for aerospace applications and ease of processing. A plurality (i.e. three or more) of generally linear aryl arms extend outwardly like spokes from a central aromatic hub through ether or ester linkages. Each spoke usually includes electronegative linkages, and is capped with one or two crosslinking functionalities (i.e. unsaturated hydrocarbon sites) which may be thermally or chemically activated to complete the advanced composite during curing. Among other methods, linear and multidimensional polyether oligomers are synthesized using nitrophthalic anhydride or halophthalic anhydride, dialcohols, or polyols, diamines, and suitable end caps.

Abstract: A catalyst composition for use in the preparation of poly(butylene terephthalate) from dimethyl terephthalate, comprising: (a) a titanium compound primary catalyst, from about 0.0005 PHR to about 5 PHR; (b) a first co-catalyst containing at least one of Zn, Co, Mn, Mg, Ca, or Pb series compounds, between about 0.0001 PHR and 5 PHR; and (c) a second co-catalyst containing an alkali metal phosphate, an alkali metal phosphite, an alkali hypophosphite, or an alkali metal polyphosphate between about 0.0001 PHR and 5 PHR; wherein PHR represents parts of the primary catalyst or the co-catalyst per one hundred parts, by weight, of dimethyl terephthalate. Preferred titanium compounds include tetrabutyl titanate or tetra(isopropyl)titanate. Preferred metal compounds for use as first co-catalyst are metal acetates. The alkali metal phosphate can be a phosphate salt containing one, two, or three metal groups; and the alkali metal phosphite can be a phosphite salt containing one or two metal groups.

Abstract: A catalyst composition for use in the preparation of poly(butylene terephthalate) from dimethyl terephthalate, comprising: (a) a titanium compound primary catalyst, from about 0.01 PHR to about 1 PHR; and (b) an alkali metal phosphate or alkali metal phosphite co-catalyst, from about 0.001 PHR to about 1 PHR; wherein PHR represents parts of the primary catalyst or the co-catalyst per one hundred parts, by weight, of dimethyl terephthalate. Preferred titanium compounds include tetrabutyl titanate or tetra(isopropyl) titanate; the alkali metal phosphate can be a phosphate salt containing one, two, or three metal groups; and the alkali metal phosphite can be a phosphite salt containing one or two metal groups. With this catalyst composition, the transesterification rate was increased by 10 percent or more. Furthermore, the reaction product poly(butylene terephthalate) shows an increased intrinsic viscosity over those without the co-catalyst, indicating a greater degree of polymerization.

Abstract: A composition comprising a copolyestercarbonate derived from a dihydric phenol, a carbonate precursor, and an aliphatic alpha omega dicarboxylic acid or ester precursor wherein the dicarboxylic acid or ester precursor has from 10 to about 20 carbon atoms, inclusive, and is present in the copolyestercarbonate in quantities of from about 2 to 30 mole percent of the dihydric phenol.

Abstract: A composition comprising a copolyestercarbonate derived from a dihydric phenol, a carbonate precursor, and an aliphatic alpha omega dicarboxylic acid or ester precursor wherein the dicarboxylic acid or ester precursor has from 10 to about 20 carbon atoms, inclusive, and is present in the copolyestercarbonate in quantities of from about 2 to 30 mole percent of the dihydric phenol.

Abstract: A polyester polymer comprising repeating units (I), or repeating units (I) and (II), and having a reduced viscosity (.eta..sub.sp /c) of 0.2 to 10.0 dl/g, measured at 20.degree. C. as a 0.5 g/dl solution dissolved in methylene chloride is prepared by allowing a dihydric phenol (III), or dihydric phenols (III) and (IV), to react with a carbonate precursor or a dibasic acid. An electrophotographic photoreceptor which comprises an electroconductive substrate and a photosensitive layer disposed on the electroconductive substrate and containing the polyester polymer as a charge transporting material or a binder resin. ##STR1## wherein, W is --O-- or single bond, X is a divalent group which is derived from a dihydric phenol containing a hydrazine structure, each of R.sup.25 and R.sup.26 is a halogen atom, an alkyl group, a cycloalkyl group or an aryl group, each of m and n is an integer of 0 to 4, Y is single bond, --O--, --S--, --SO--, --SO.sub.2 --, --CR.sup.27 R.sup.28 --, a 1,1-cycloalkylene group or an .alpha.

Abstract: Granules collected from a solution of a polycarbonate, an integrated structure of independent fine particles constituting the granules being formed at least on the surfaces of the granules; and a process for preparing the granules of the polycarbonate which comprises the steps of adding a poor solvent to the polycarbonate solution, and then agitation-granulating fine particles of the polycarbonate into the granules, while stirring involving a shear force-imparting function is carried out under heating. According to the present invention, the polycarbonate or the like can be collected from its organic solvent solution as the granules having good drying properties.

Abstract: Thermotropic melt processable liquid crystalline aromatic polyesters comprising units derived from a dicarboxylic acid and from a mixture of aromatic diols in which from 50% to 80% is (1-phenylethyl)hydroquinone and from 20% to 50% is hydroquinone.

Abstract: A process for preparing a polyestercarbonate copolymer which is nearly devoid of diaryl-carbonates and that exhibits a glass transition temperature lower than bisphenol-A carbonate homopolymer, and that shows improved processability is herein described. The desired lower Tg and improved flow can be achieved by the polycondensation of a dihydric phenol and aliphatic dicarboxylic acid. The condensate is polymerized with a carbonate forming reagent.

Abstract: The description relates to novel liquid-crystalline polyesters containing the following repeating units: A having the formula: ##STR1## and B having the formula ##STR2## The novel polyesters are of use e.g. as starting materials for production of fibres with improved mechanical properties. They can either be converted as such into fibres or can be added to conventional fibre-forming matrix polymers.

Abstract: Novel thermotropic liquid crystalline polyesters derived from t-butylhydroquinone, terephthalic acid, 2,6-naphthalene dicarboxylic acid and 4-hydroxybenzoic acid are described. These polymers are useful as molding resins.

Abstract: A reduced glass transition temperature copolyester-carbonate which displays non-Newtonian melt behavior was synthesized by using bisphenol-A, a dicarboxylic acid and a trisphenol. The branched copolymer was obtained by interfacial phosgenation. One of the compositions described displays a Tg of about 127.degree. C. and twice the melt flow index of a branched polycarbonate of corresponding molecular weight or intrinsic viscosity.

Abstract: Disclosed is a process for blow molding articles from liquid crystal polymers containing ionic moieties in the backbone. The ionic moieties increase the melt viscosity of the polymers sufficiently high to blow mold articles therefrom. An illustrative liquid crystal polymer is made from 4-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid and sodium 5-sulfoisophthalate.

Abstract: Hydroxy-substituted-bis-phenyl cyclopropanes of formula (I): ##STR1## wherein R.sub.1 and R.sub.2 are selected from H or OH, at least one of R.sub.1 and R.sub.2 being o, m or p-OH, are useful as monomers to provide cross-linkable polymers useful in fiber reinforced plastics, thermosetting molding compounds, elastomers, advanced composites and other applications; the compounds (I) may be produced by the base catalyzed decomposition of a pyrazoline of formula (II): ##STR2## wherein R.sub.1 and R.sub.2 are as defined hereinbefore.

Abstract: Aqueous filler composition comprising a polyester resin, which is built up of the educts (a), (b), (c), (d) and (e) or their ester-forming derivatives, the sum of the reactants corresponding to 100 mol-% and the ratio of the sum of the hydroxyl equivalents (eg OH) to the sum of the carboxyl equivalents in the reactants being between 0.5 and 2.0, where(a) is at least one dicarboxylic acid which is not a sulfo or phosphorus monomer,(b) is 0 to 15 mol-% of at least one difunctional sulfo or phosphono monomer, the functional groups of which are carboxyl and/or hydroxyl groups, having at least one sulfonate or phosphonate group,(c) is at least one difunctional compound which is derived from a glycol containing two --C(R).sub.

Abstract: The present invention provides a novel liquid crystalline polyester comprising structural units represented by the following general formulae A, B, C and D: ##STR1## where X and Y are each independently H, Cl, Br or an alkyl group having 1 to 4 carbon atoms, the molar ratio of A/B is in the range from 49/1 to 20/30 and that of C/D is in the range from 10/40 to 45/5.

Abstract: Thermally depolymerizable polyoxalate and polymalonate polymers which contain hydrocarbon groups having from 6 to 30 carbon atoms and a tertiary carbon atom attached to at least one of the bridging oxygen atoms in the structure are usable as binders for powdered glass ceramic or metallic materials, and as rheological control agents in paste formulations.

Abstract: A liquid-crystal display device having a liquid-crystal layer held between a pair of substrates each having a transparent electrode and an alignment film formed successively on the inner surface, characterized in that the material of the alignment film on at least one of the opposing faces between the substrates is a polymer having recurring units (I, II and III), the recurring unit (I) being represented by formula (A), ##STR1## recurring unit II being a dioxyaryl portion represented by the formula --O--Ar--O-- (where Ar is a divalent group having at least one aromatic ring which may contain at least one substituent selected from a C.sub.1-4 alkyl group, a C.sub.1-4 alkoxy group, a halogen, a phenyl and a substituted phenyl), and recurring unit (III) being a dicarboxyaryl portion represented by formula (B) ##STR2## (where Ar' may be the same as or different from Ar and has the same meaning as Ar).

Abstract: A polyester resin comprising units of a dicarboxylic acid component composed mainly of an aromatic dicarboxylic acid or its ester forming derivative and a diol component composed mainly of ethylene glycol and an ethylene oxide adduct of a bisphenol compound or its derivative.The resin may advantageously be used as a molding material for various moldings such as extrusion molding, blow molding, vacuum molding and injection molding.

Abstract: An aromatic polyester superior in heat resistance and mechanical properties and satisfactory in lightness and color tone is provided. The aromatic polyester has resorcinol structure, has the formula (1), ##STR1## wherein R is halogen, C.sub.1 -C.sub.5 alkyl, or phenyl; m is an integer of 0 to 2, and when m is 2, the two substituents represented by R may be different from each other; and gives a powder fraction having a lightness (L value) of 70 or more and a red degree (a value) of 5 or less, which powder fraction is obtained by pulverizing the heat-resistant aromatic polyester, sieving the pulverized polyester by Tyler standard sieves and being allowed to pass through 60-mesh sieve but not 325-mesh sieve.

Abstract: The heat resistance of polyester liquid crystalline polymers containing repeat units in selected ratios derived from hydroquinone, 4,4'-biphenol, terephthalic acid, 4-hydroxybenzoic acid, and one or both of 4,4'-bibenzoic acid and 2,6-naphthalene dicarboxylic acid is improved by the addition thereto of 15 to 3000 ppm of an alkali metal or 50 to 3000 ppm magnesium or calcium.

Abstract: Thermosetting esterimide oligomers of formulas (IA) and (IB) are disclosed: ##STR1## where A.sub.1, A.sub.2 and A.sub.4 are divalent organic groups, A.sub.3 is a monovalent organic group and A.sub.1, A.sub.2, A.sub.3 and A.sub.4 may be the same or different, with m being an integer of 1-30. The above compounds provide hard substances having excellent workability, heat resistance and mechanical properties.

Abstract: It is intended to provide a liquid crystalline polyester whose orientation in the state of liquid crystal can be easily immobilized as glass phase and which is suitable for application to optical elements.A liquid crystalline polyester comprising repeating units a, b, c and d represented by the following general formulae: ##STR1## where X and Y are each independently a hydrogen atom, Cl, Br or an alkyl group having 1 to 4 carbon atoms, the repeating units a, b, c and d being in mole ratios such that (a+b)/(c+d) is approximately 1, a/b is in the range from 98/2 to 50/50 and c/d is in the range from 70/30 to 10/90.

Abstract: A novel wholly aromatic polyester capable of forming an anisotropic melt phase is provided. Such polyester has been demonstrated to be capable of forming quality molded articles having a combination of excellent heat resistance and mechanical properties. The resulting polyester further is capable of readily being melt processed while using conventional equipment. Four essential recurring units are present in the polyester of the present invention wherein (I) is derived from 2,6-napthalenedicarboxylic acid and/or 4,4'-biphenyldicarboxylicacid; (II) is derived from another dicarboxylic acid (as defined) such as terephthalic acid; and (III) is derived from aromatic diols (as defined) such as 1,4-dihydroxybenzene and 4,4'-dihydroxybiphenyl; and (IV) is derived from another aromatic diol (as defined), such as 4,4'-dihydroxydiphenyl ether. In a preferred embodiment, an inorganic filler is dispersed therein.

Abstract: Polybenzoxazole or polybenzothiazole polymer dopes are spun through a spinneret having an orifice density of more than 0.25 per cm.sup.2 to form filaments. The filaments formed then pass through an air gap which has a gas flowing into it at a temperature of between about 5.degree. C. to about 100.degree. C. and at a flow rate between about 0.1 meters/second and about 2.0 meters/second. The filaments cool in the air gap and are then coagulated. During or after coagulation the filaments are combined into one or more fibers. By this method of controlling the temperature in the air gap it is possible to stably spin polybenzoxazole or polybenzothiazole fibers at relatively high final line speeds.

Abstract: Thermoplastic polyester-imides having improved mechanical properties, characterized in that they consist of recurring units of the formula I ##STR1## in which R denotes an 2,4-tolylene, 2,6-tolylene, 2,5-bis(4-phenylenethio) thiadiazole,or a 1,4-bis(phenylenethio)diphenyl sulfone radical, a process for their preparation and their use for the production of industrial components of plastic.

Abstract: The invention relates to amorphous polyesterimides which comprises 50 to 100 mole-% of units of formula II ##STR1## and from 0 to 50 mole-% of units of formula ##STR2## in which units R.sub.1 and R.sub.2, independentlyof one another, are H, branched or unbranched alkyl radicals having 1 to 6 carbon atoms, branched or unbranched alkoxy radicals having 1 to 6 carbon atoms, or F, Cl or Br.The polyesterimides according to the invention are suitable for the production of molding compositions, moldings, fibers and films.

Abstract: A curable formaldehyde-free phenolic resin having formula (I): ##STR1## wherein a and b each represent an integer equal to or greater than 1, a+b multiplied by n is an integer of about 3 to 100; ##STR2## m is 0 or 1; and R is hydrogen, halogen, alkyl having about 1 to 12 carbon atoms, aryl having about 6 to 12 carbon atoms, allyl having 3 or 4 carbon atoms, aralkyl having about 7 to 13 carbon atoms, alkaryl having about 7 to 13 carbon atoms, alkoxy having about 1 to 4 carbon atoms, aryloxy having about 6 to 12 carbon atoms, or ##STR3## and methods for preparing such resin are described.

Abstract: A method for producing a liquid crystalline polyester, which comprises reacting compounds of the following formulas: ##STR1## and a dicarboxylic acid of the following formula ##STR2## wherein R.sup.1 is a bivalent aromatic hydrocarbon group having from 6 to 18 C atoms as starting material, for polycondensation in a molten state.

Abstract: Novel cyclic imino ether compositions containing one or more mesogenic moieties, when polymerized, result in products having improved properties.

Abstract: A thermotropic copolyester, which displays a liquid-crystal phase of nematic type, within a desired temperature range, contains units deriving from:(a) a saturated, aliphatic dicarboxy acid;(b) 4,4'-dihydroxy-biphenyl and/or mono- or di-alkyl- or -alkenyl-derivatives thereof;(c) 4-hydroxy-benzoic acid and/or alkyl- or alkenyl-derivatives thereof.Such a copolyester improves the processability of unsaturation-containing elastomers and enhances the mechanical properties of subsequently vulcanized products.

Abstract: Provided are novel thermotropic liquid crystal polyesters consisting essentially of the following structural units (1), (2) and (3) or those (2), (3), (4) and (5) and shaped articles comprising these polyesters. Also provided are packaging materials and containers comprising the above thermotropic liquid crystal polyesters or a polyester consisting essentially of the following structural units (2), (3), (5) and (6).

Abstract: A composition comprising a copolyestercarbonate derived from a dihydric phenol, a carbonate precursor, and an aliphatic alpha omega dicarboxylic acid or ester precursor wherein the dicarboxylic acid or ester precursor has from 10 to about 20 carbon atoms, inclusive, and is present in the copolyestercarbonate in quantities of from about 2 to 30 mole percent of the dihydric phenol.

Abstract: Translucent, pore-free sintered aromatic polyesters made from diphenols such as 1,1-bis(4-hydroxyphenyl)fluorene and phthalic-acid halides evince one or more glass transition points in the range of 220.degree. to 400.degree. C. and a tensile strength larger than 40 N/mm.sup.2 but advantageously larger than 60 N/mm.sup.2. They also evince higher resistance to some solvents such as carbon tetrachloride when in the form of poured films as regards the same material. To manufacture the sintered article, the polyester powder is subjected in a closed mold to a pressure larger than 3,000 N/cm.sup.2, the mold meantime being slowly heated and then kept for an appreciable time above the glass transition point and thereupon being slowly cooled. As a rule the sintered articles are used as semi-finished products or as pre-formed component-blanks from which the desired end products are made by mechanical cutting.

Abstract: A copolymer of an aromatic anhydride and an aliphatic ester suitable for use in surgical devices and a process for making said copolymer.

Abstract: Thermotropic liquid crystalline poly(ester-amide) compositions are disclosed which comprise a bis(4-carbonyl phenylene) terephthalate unit and a unit derived from an N-substituted hydrocarbylenediamine (e.g., one derived from an N,N-dialkylalkylene).

Abstract: A liquid crystalline polyester comprising dicarboxylic acid units of the following formula (1): ##STR1## wherein R.sup.1 is a bivalent aromatic hydrocarbon group having from 6 to 18 carbon atoms, diol units of the following formula (2):--OCH.sub.2 CH.sub.

Abstract: Pseudo network polymer is characterized by a network of linear segments which is composed of recurring units of a multivalent branching moiety, a chain-defining moiety, and a coupling moiety. The polymer may be formed into film, fiber and molded articles which exhibit improved mechanical properties in the transverse direction.

Abstract: An aromatic polyester:(1) consisting essentially of a polymer unit A of the formula (1), ##STR1## a polymer unit B of the formula (2), ##STR2## and a polymer unit C of the formula (3), ##STR3## the above polymer units being bonded together forming ester linkages in a polymer chain,(2) the polymer unit C being contained in an amount of 10 to 35 mol % based of the total amount of the polymer units B and C,(3) the polyester being semicrystalline,(4) the polyester having an inherent viscosity, measured in a phenol/1,1,2,2-tetrachloroethane mixed solvent (weight ratio=60/40) at 35.degree. C., of at least 0.3; a process for its production; and a resin composition containing it.

Abstract: A thermotropic liquid crystalline polyester is produced by carrying out polycondensation of ester monomer [I-2], an aromatic dicarboxylic acid [II] and an aromatic carboxylic acid [III-2]. The amounts of the compounds [I-2] and [II] are substantially equivalent and the amount of the compound [III-2] is not more than 20 times that of [I-2] by mole. A thermotropic liquid crystalline polyester having good heat resistance, fluidity and uniformity can be produced.

Abstract: Aromatic polyesters containing monomer units derived from terephthalic acid, one or more aromatic diols, such as bisphenol A, and one or more aromatic hydroxyacids, such as 4-hydroxybenzoic acid or 6-hydroxy-2-naphthoic acid, are described. The aromatic hydroxyacid is incorporated in a quantity sufficient to yield a polymer which is non-crystalline and which has a low enough softening temperature that it can be readily synthesized in the melt with a useful molecular weight without the need for subsequent solid state polymerization. These aromatic polyesters are useful for making transparent articles with high temperature properties.

Abstract: This invention pertains to novel copolyesters consisting essentially of units (I), (II), (III), and (IV). ##STR1## and blends of these polymers and articles made from both. Units (I), (II), (III), and (IV) are present in specified proportions as defined in the "Description of the Invention."The instant copolyesters display orientation in the molten state, good fiber ratings and high strength; they have melting points in the range of from about 340.degree. to about 400.degree. C. and are melt-processible. Advantageously, these compositions filled with about 30 weight percent of glass fibers display heat distortion temperatures of over 240.degree. C. up to about 280.degree. C. and higher, when measured under a load of 264 psi. When blended, certain properties are improved, particularly they are easier to melt fabricate, have a decreased tendency to blister and increased strength.

Abstract: There are described aromatic copolyamides which are soluble in organic polyamide solvents and which consist essentially of recurring structural units of the formulae Ia, Ib and Ic on the one hand and Ia, Ib and Ie on the other[--OC--R.sup.1 --CO--NH--R.sup.2 --NH--] (Ia), [--OC--R.sup.1 --CO--NH--R.sup.3 --NH--] (Ib),[--OC--R.sup.1 --CO--NH--R.sup.4 --NH--] (Ic), [--OC--R.sup.1 --CO--NH--R.sup.7 --NH--] (Ie),where R.sup.1 and R.sup.7 are divalent aromatic radicals whose valence bonds are in the para or a comparable coaxial or parallel position relative to one another, R.sup.2 is a radical of the formula III ##STR1## and R.sup.3 and R.sup.4 are radicals of the formula IV ##STR2## where Z is --O--, --S--, --CO--, --SO.sub.2 --, C.sub.1 -C.sub.10 -alkylene or --O--R.sup.1 --O-- and R.sup.6 is in each case hydrogen or an inert substituent.The mole fractions of the individual structural features in the copolyamides are defined within selected limits.

Abstract: Isotropic polyesters containing a repeat unit derived from 4,4'-bis(3-hydroxyphenoxy)biphenyl, and especially poly(imide-esters) containing that diol, trimellitic anhydride and at least one diamine and/or aminocarboxylic acid. Such polyesters have a good combination of physical and melt properties, making them easy to shape and them useful for mechanical parts and fibers.

Abstract: A process for producing a branched polycarbonate comprising reacting a dihydric phenol, such as 2,2-bis(4-hydroxyphenyl) propane, a polyfunctional organic compound, such as 1,1,1-tris-(4-hydroxyphenyl)ethane, and phosgene to produce a polycarbonate oligomer, and then polycondensing with stirring the polycarbonate oligomer with a dihydric phenol, such as 2,2-bis(4-hydroxyphenyl) propane, and a monohydric phenol, such as p-tert butylphenol, whereby the interfacial area of the resultant emulsion is not less than 40 m.sup.2 /L.

Abstract: The present invention relates to polyesters capable to give moldings having excellent flow characteristics, heat resistance and mechanical properties.These polyesters are prepared by copolymerizing specified amounts of specific dioxycompounds such as t-butylhydroquinone, phenylhydroquinone and so on with polyesters comprising specified amounts of p-hydroxybenzoic acid, 4,4'-dihydroxybiphenyl, hydroquinone and terephthalic acid or terephthalic acid and isophthalic acid.

Abstract: A polyester resin for a toner capable of being stably prepared without an occurrence of an abrupt crosslinking reaction is provided. This polyester resin has a crosslinked structure and is derived from (a) at least one member selected from the group consisting of tribasic and tetrabasic carboxylic acid components and trihydric and tetrahydric alcohol components, (b) an aromatic or alicyclic diol component, at least one of the hydroxyl groups of which is a secondary hydroxyl group, (c) optionally other diol component, and (d) a dicarboxylic acid component, wherein the contents of the units of the component (a) and the units of the component (b) satisfy the requirement represented by the following formula (1):(8m+20n)a-(80m+80n).ltoreq.b.ltoreq.

Abstract: A polyarylate is formed by reacting a mixture of esters of a dihydric phenol and trisphenol, at least one aromatic dicarboxylic acid, an alkali metal catalyst, an inert diluent having a boiling point of from about 200.degree. C. to about 300.degree. C. Polyarylates of improved shear sensitivity and higher molecular weight can be formed.

Abstract: In a continuous process for the manufacture of aromatic polyesters by polycondensation of mono- or multi-nuclear substituted or unsubstituted diphenols, with halides of aromatic dicarboxylic acids according to the two-phase interface polycondensation process, the first step is to produce continuously a fine pre-emulsion with an organic solvent and from the aqueous phase, consisting of a solution obtained from the diphenols, of an alkaline hydroxide in order to form the diphenates and possibly of a phase transfer catalyst in water or in a mixture of water and of an organic solubilizer. This pre-emulsion is fed in quantities to a dispersion unit jointly with the organo-liquid phase forming the acid chloride solution.