Abstract: The use of phenols having a branched structure as terminal groups in polycarbonates, polyester carbonates and polyesters is disclosed. Also disclosed are polycarbonates, polyester carbonates and polyesters having such branched terminal groups, the process for their production and molded parts made therefrom.

Abstract: The present invention provides a method for producing a liquid crystalline polyester which is produced from an aromatic carboxylic acid, an aromatic hydroxycarboxylic acid, an aromatic diol and/or an aromatic hydroxylamine, including a polymerization step (1) for producing a prepolymer of the liquid crystalline polyester and a solid-state polymerization step (2) for elevating the polymerization degree of the resultant prepolymer, the number of aromatic ring terminal groups of the prepolymer satisfying the following equation (i): [(the number of aromatic ring terminal groups)/[(the number of carboxylic terminal groups)+(the number of aromatic ring terminal groups)]]×100≧7(%) (i). According to the invention, all-aromatic type liquid crystalline polyesters can be produced within a short time and at low cost.

Abstract: A two step method for solid state polymerization of dry crystalline thermoplastic polymers to form polymers with superior mechanical properties, first by mechanically fluidizing dry crystalline thermoplastic polymer particles in the absence of oxygen by means of blades moving through the fluidized polymer particles at velocities sufficient to heat the particles to an incipient melt temperature and maintain the temperature until solid state polymerization provides the desired molecular weight and before chemical degradation of the polymer occurs; and second by immediately quenching by application of liquefied cryogenic gases directly to the surfaces of the polymer particles in amounts sufficient to cool the particles to temperatures lower than the glass transition temperature of the polymer before crystals in the polymer aggregate into large spherulites.

Abstract: A method for decreasing acetaldehyde content of melt processed polyester comprising combining with polyester an organic additive compound that scavenges acetaldehyde from polyester. The organic additive compound comprises at least two component molecular fragments, each component molecular fragment comprising at least two hydrogen substituted heteroatoms bonded to carbons of the respective component molecular fragment. Each component molecular fragment is reactive with acetaldehyde in the polyester to form water and a resulting organic compound comprising an unbridged five or six member ring including the at least two heteroatoms. The reduced acetaldehyde content polyester is particularly useful for making containers such as for packaging beverages.

Abstract: The present invention provide a liquid crystalline polyester that can be used in production of a molded article having sufficient mechanical strengths in which the melted liquid crystalline polyester has sufficient fluidity in thin-walled portions when the thin-walled molded article is manufactured, and to provide a method for producing the liquid crystalline polyester. A liquid crystalline polyester obtained by copolymerizing 4-acyloxybenzoic acids (I) and 2-acyloxy-6-naphthoic acids (II) in the presence of an imidazole (V) can be used in production of a molded article in which the melted liquid crystalline polyester has sufficient fluidity in thin-walled portions when the thin-walled molded article is manufactured, and which has sufficient mechanical strengths as well, thereby completing the present invention.

Abstract: The present invention provides compositions comprising (a) a thermally stable polymer comprising resorcinol arylate polyester chain members substantially free of anhydride linkages linking at least two mers of the polymer chain, and (b) at least one auxiliary stabilizer additive selected from the group consisting of 2,2′-(1,4-phenylene)bis(4H-3,1-benzoxazin-4-one) and 1,3-bis[(2-cyano-3,3-diphenylacryloyl)oxy]-2,2-bis[[(2-cyano-3,3-diphenylacryloyl)oxy]methyl]propane. Both multilayer and unitary articles comprising the composition are also provided.

Abstract: Thermally stable polymers comprising chain members derived from at least one 1,3-dihydroxybenzene moiety and at least one aromatic dicarboxylic acid moiety, said polymer being substantially free of anhydride linkages linking at least two mers of the polymer chain, are prepared using an interfacial method comprising the steps of: (a) combining at least one 1,3-dihydroxybenzene moiety and at least one catalyst in a mixture of water and at least one organic solvent substantially immiscible with water; (b) adding to the mixture from (a) a controlled stoichiometric ratio of at least one acid chloride and at least one base while maintaining the pH between about 4 and about 8.5, and (c) adjusting the pH of the reaction mixture to a value in the range of about 7 and about 9 following complete addition of acid chloride, and stirring the reaction mixture for a time sufficient to destroy any anhydride linkages in the polymer chain.

Abstract: The present invention is a process for making a low color copolymer of ethylene glycol, isosorbide and terephthalic acid or dimethyl terephthalate. This copolymer, poly(ethylene-co-isosorbide) terephthalate, is useful for making bottles, hot-fill containers, films, sheet, fiber, strand and optical article applications. It can also be used to make polymer blends and alloys.

Abstract: A batch type apparatus for producing a liquid crystalline polymer includes a reactor, a first gas-pressurizing unit, a die-head, a shut-off valve, and a die-plate. The reactor produces a liquid crystalline polymer capable of forming an anisotropic melt phase. The reactor has a discharge port at a lower portion thereof. The first gas-pressurizing unit is attached to the reactor for discharging under pressure the liquid crystalline polymer by use of an inert gas. The die-head includes, at one end portion thereof, a discharge valve which opens and closes the discharge port; at a middle portion thereof, an internal chamber which communicates with the discharge port and is heated and regulated from the peripheral surface thereof; and at the other end portion thereof, an opening which forms an end portion of the internal chamber. The shut-off valve is connected to the other end portion of the die-head and capable of opening and closing the opening. The die-plate is disposed at the opening of the shut-off valve.

Abstract: Articles made from a thermoplastic resin composition comprising a high modulus fiber and a resorcinol polyester or resorcinol polyester carbonate resin showing high strength and stiffness along with surprisingly good retention of gloss and color when exposed to weathering.

Abstract: Biodegradable resin products consisting essentially of a polymeric resin of starch, polyesters such as polylactic acid, or other suitable polyesters. In admixture with the resin is a particulate vapor phase corrosion inhibitor selected from amine salts, triazole derivatives, alkali dibasic acid salts, and mixtures thereof, and is present in an amount ranging from between about 1% and 3% by weight of the polymeric resin and which is shaped into formed articles.

Abstract: A process for preparing polyester pellets which involves blending polyethylene terephthalate and polyethylene isophthalate copolymer before solid state polymerization, the polyethylene isophthalate copolymer being composed of dicarboxylic acid constituent units derived from dicarboxylic acids containing terephthalic acid and isophthalic acid and diol constituent units derived from diols containing ethylene glycol and 1,3-bis(2-hydroxyethoxy)benzene, palletizing the blend and crystallizing the pellets.

Abstract: A polyester having less than 50 hydrogen-carbon bonds per 1000 molecular weight units exhibits very low optical loss in the range of wavelengths commonly used for optical communication, and exhibits other physical properties suitable for use as a waveguide core material and/or a waveguide cladding material in optical fibers and/or planar optical devices.

Abstract: A polyether ester elastomer comprising about 90-about 60 weight % polytrimethylene ether ester soft segment and about 10-about 40 weight % trimethylene ester hard segment, and use thereof in fibers and other shaped articles. The fibers have excellent physical properties, including superior strength and stretch recovery.

Abstract: Thermally stable polymers comprising resorcinol arylate chain members are prepared using an interfacial method comprising the steps of: interfacial method for preparing polymers comprising resorcinol arylate polyester chain members substantially free of anhydride linkages linking at least two mers of the polymer chain, comprising the steps of: (a) preparing an aqueous solution comprising at least one resorcinol moiety, said solution having a pH less than or equal to about 5; (b) after step (a), preparing a mixture comprising the resorcinol moiety, at least one catalyst and at least one organic solvent substantially immiscible with water; and (c) adding to the mixture from (b) at least one dicarboxylic acid dichloride while maintaining the pH between 3 and 8.5 through the presence of an acid acceptor, wherein the total molar amount of acid chloride groups is stoichiometrically deficient relative to the total molar amount of phenolic groups.

Abstract: A process for producing a wholly aromatic polyester which is excellent in heat resistance, mechanical properties and yet color and has a high degree of polymerization by melt polymerizing a dicarboxylic acid and a diol directly on an industrial scale at a low cost in a short period of time without esterifying the dicarboxylic acid or diol in advance. To produce the wholly aromatic polyester by reacting and molding an aromatic dicarboxylic acid such as terephthalic acid, an aromatic diol such as 2,2-bis(4-hydroxyphenyl)propane and a diaryl carbonate by heating, a combination of a specific pyridine compound and an alkali metal (bi)carbonate, a combination of a specific pyridine compound and an organic tin compound or a specific titanium compound is existent as a catalyst. Thereby, the wholly aromatic polyester having the above properties is obtained.

Abstract: Thermoplastics may be melt spun at high production rates, and without physical property degradation, by spinning a blend of the thermoplastic and a minor amount of a specified liquid crystalline polymer.

Abstract: Highly stretchable, anisotropic melt-forming polymers consisting essentially of recurring units derived from p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, isophthalic acid, terephthalic acid and hydroquinone are disclosed.

Abstract: It is an object of the present invention to provide a fiber-treatment capable of providing improved flame retardancy towards synthetic fiber comprising polyester.

Abstract: The invention provides a method for producing a thermotropic liquid crystalline polymer of high quality at high yield and in short polymerization time, which method includes polymerizing staring monomers I, II, III, and IV, i.e., (I) an aromatic hydroxycarboxylic acid, etc.; (II) an aromatic dicarboxylic acid and an alicyclic dicarboxylic acid; (III) an aromatic diol, an alicyclic diol, an aliphatic diol, etc.; and (IV) an aromatic hydroxylamine, an aromatic diamine, etc. in the presence of an acylating agent, wherein the starting materials are charged so as to satisfy the following equations (1) to (4): 0.0015≦((A)−(B))/((A)+(B))≦0.006  (1); 1.01≦(D)/(C)≦1.08  (2); 0≦(E)≦40  (3); and (D)/(C)≧−0.002 ×(E)+1.

Abstract: A molded structure comprises a decorative film or substrate, and an adjacent injection molded polymeric base comprising a substantially transparent cycloaliphatic polyester resin which may have an opening for exposing the transparent polymeric base resin to the exterior of the molded article, and a process for making the molded structure is described.

Abstract: A stretch blow bottle made from a polyester resin composition which comprises: (A) 60 to 99% by weight of a polyethylene terephthalate resin and (B) 1 to 40% by weight of a polyethylene isophthalate resin, wherein 300 square microns of a section exposed by cutting the neck of the bottle contains less than one particle of the polyethylene isophthalate resin (B) having a diameter of 0.1 micron or above in the polyethylene terephthalate resin (A) as the matrix.

Abstract: An unsaturated carboxyl group-terminated polyester resin having suitable properties for use in a powder coating for wood and other temperature-sensitive substances is disclosed.

Abstract: A topsheet for a touch screen includes a support layer having a touch surface and a second surface opposite the touch surface; a polarizer layer having a first surface and a second surface with the first surface of the polarizer in contact with the second surface of said support layer; and a first conductive layer in contact with the second surface of said polarizer.

Abstract: An adhesive polyester film which comprises a biaxially oriented polyester film base layer and an adhesive layer and which is particularly useful as a base layer for a sublimation-type thermosensitive image transfer recording material. This base layer has no point at which the gradient of its temperature-dimensional change curve changes from a positive value to a negative value when temperature is elevated from the glass transition temperature of the polyester to 240° C. and does not show a dimensional change of more than 5%. The adhesive layer is made from (i) a water-soluble or water-dispersible resin of a polyester modified by a vinyl resin or (ii) a crosslinked resin of a mixture of a water-soluble or water-dispersible acrylic resin, a water-soluble or water-dispersible polyester resin and an epoxy resin crosslinking agent.

Abstract: Provided is a liquid crystalline polymer which is obtained by copolymerizing at least one polyfunctional aromatic monomer selected from the group consisting of the compounds represented by the formulae (I), (II) and (III) below with at least one polymerizable monomer. The liquid crystalline polymer of the present invention is excellent in heat resistance, molding properties, flow properties and mechanical properties, especially it provide molded article with improved weld strength.

Abstract: Provided are a aromatic liquid crystalline polyester resin having improved low temperature processability, a film having excellent gas barrier property. The aromatic liquid crystalline polyester resin is obtained from an aromatic hydroxycarboxylic acid, an aromatic dicarboxylic acid and an aromatic diol, by optimizing formulation ratio of the above-described three components. The aromatic liquid crystalline polyester resin comprises an aromatic hydroxycarboxylic acid unit, an aromatic dicarboxylic acid unit and an aromatic diol unit, as repeating units, wherein the repeating unit (A) as an aromatic hydroxycarboxylic acid unit, is contained in an amount of 30 mol % or more based on the total amount of repeating units, and the polyester has a logarithmic viscosity of 1.5 dl/g or more, a flow temperature of 300° C. or less, and a melt tension measured at a temperature higher than the flow temperature by 25° C. or more of 1.

Abstract: A wholly aromatic copolyester having repeating units of the formula: wherein Ar1 is wherein Q is selected from the group consisting of —H, —CH3, —CF3, —Cl, —Br, and —C6H5; wherein Ar2 is selected from the group consisting of wherein X is selected from the group consisting of —Br, —Cl, —CH3 and —C6H5; wherein Ar3 is wherein Ar4 is selected from the group consisting of wherein m has a value of 0.05 to 0.95 and n has a value of 100-m, is characterized by accessible nematic-isotropic transition temperatures providing outstanding orientational order and mechanical properties.

Abstract: Disclosed is a select class of liquid crystalline polyesters and molding compositions comprising the polyesters and glass fiber. The liquid crystalline polyesters consist essentially of (1) diacid residues consisting essentially of (i) cyclohexanedicarboxylic acid residues and (ii) other diacid residues selected from terephthalic acid residues, 2,6-naphthalene-dicarboxylic acid residues, or a mixture thereof; (2) diol residues consisting essentially of hydroquinone residues, 4,4′-biphenol residues or a mixture thereof; and, optionally, (3) p-hydroxybenzoic acid residues. In the above definition, the moles of diol residues are equal to the moles of diacid residues and the total of the (1), (2) and (3) mole percentages is equal to 100. The liquid crystalline polyesters have melting points determined by differential scanning calorimetry equal to or less than 360° C.

Abstract: The invention provides a method for producing a thermotropic liquid crystalline polymer of high quality at high yield and in short polymerization time, which method includes polymerizing staring monomers I, II, III, and IV, i.e., (I) an aromatic hydroxycarboxylic acid, etc.; (II) an aromatic dicarboxylic acid and an alicyclic dicarboxylic acid; (III) an aromatic diol, an alicyclic diol, an aliphatic diol, etc.; and (IV) an aromatic hydroxylamine, an aromatic diamine, etc.

Abstract: Disclosed are novel compositions containing an LCP and one or more aromatic phosphonites. Also disclosed is a novel process for preparing LCPs in the presence of one or more aromatic phosphonites. The process enables the preparation of LCPs in a more controlled manner so that the LCPs have excellent thermal/oxidative stability. The LCPs are useful where the combination of good mechanical properties, excellent thermal resistance properties, and excellent thermal stability are desired, such as in electrical/electronic applications and electrical connectors.

Abstract: A gas barrier polymer composition with active hydrogen functionality is provided. The polymer may be prepared by reacting a solution of organic diacid containing at least one active hydrogen group and diglycidyl ether in the presence of an optional catalyst. The pressure, temperature, and time parameters of the reaction are preferably regulated to prevent degradation and subsequent incorporation of degradation products of organic diacid containing at least one active hydrogen group into the gas barrier polymer composition. A formulation of the gas barrier polymer composition and a carrier may be used to coat plastic materials, containers, and preforms. The gas barrier polymer composition may also be employed in a method of making multilayer packaging materials or container preforms. The multilayer packaging materials or preforms can be used to make containers useful in packaging gas sensitive substances.

Abstract: A process for preparing a polyester carbonate is provided. The process comprises the steps of: (I) reacting a diacid with a carbonic acid diester and a catalyst in the presence of a polycarbonate oligomer via melt condensation polymerization to form a pre-polymer; and (II) reacting the pre-polymer via solid state polymerization to form a polyester carbonate.

Abstract: An aromatic polyester having the following structural units, (1), (2), (3), (4) and (5), wherein the amount of the structural unit (1) is 30 to 50% based on the total of the all structural units, (2)/(3) is more than 2.78 and smaller than 4, (4)/(5) is more than 1.0 and smaller than 1.5, and {(2)+(3)}/{(4)+(5)} is from 0.9 to 1.1: wherein Ra, Rb, Rc, Rd, Re and Rf each independently represents a lower alkyl group, lower alkoxy group, phenoxy group, phenyl group or halogen atom, and l, m, n, o, p and q each independently represents an integer from 0 to 3, is provided; and the aromatic polyester has excellent molding property and a molded article made from this polyester has excellent soldering temperature resistance and rigidity.

Abstract: The invention relates to optical elements comprised of an optical isotropic completely aromatic polyester with a glass transition temperature Tg≧180° C.

Abstract: Disclosed are polyester pellets made of a polyester which comprises dicarboxylic acid constituent units derived from dicarboxylic acids containing terephthalic acid and isophthalic acid and diol constituent units derived from diols containing ethylene glycol and 1,3-bis(2-hydroxyethoxy)benzene, and which has the properties: constituent units derived from terephthalic acid are 15 to 99.5% by mol and constituent units derived from isophthalic acid are 0.5 to 85% by mol, both based on the total amount of dicarboxylic acid isophthalic acid constituent units (i); constituent units derived from ethylene glycol are 25 to 99.5% by mol and constituent units derived from 1,3-bis(2-hydroxyethoxy)benzene are 0.5 to 75% by mol, both based on the total amount of the diol constituent units (ii); the intrinsic viscosity is in the range of 0.5 to 1.5 dl/g; and the melting point (Tm (°C.)), as measured by a differential scanning calorimeter, satisfies the formula [1/527−0.

Abstract: Disclosed is a select class of liquid crystalline polyesters and molding compositions comprising the polyesters and glass fiber. The liquid crystalline polyesters consist essentially of (1) diacid residues consisting essentially of (i) cyclohexanedicarboxylic acid residues and (ii) other diacid residues selected from terephthalic acid residues, 2,6-naphthalenedicarboxylic acid residues, or a mixture thereof; (2) diol residues consisting essentially of hydroquinone residues, 4,4′-biphenol residues or a mixture thereof; and, optionally, (3) p-hydroxybenzoic acid residues. In the above definition, the moles of diol residues are equal to the moles of diacid residues and the total of the (1), (2) and (3) mole percentages is equal to 100. The liquid crystalline polyesters have melting points determined by differential scanning calorimetry equal to or less than 360° C.

Abstract: A method of producing a thermotropic liquid crystalline copolyester having an extremely small amount of out-gases comprising the steps of: (1) charging in a reactor 5-100 mol % of aromatic hydroxycarboxylic acid, 0-47.5 mol % of aromatic dicarboxylic acid and 0-47.5 mol % of aromatic diol, so that the sum of mol % of each material is 100 mol % and the molt of aromatic dicarboxylic acid and that of aromatic diol are substantially equal; (2) adding acetic anhydride of an amount which satisfies the formula, (B-C)/A≧1.04, “A” representing the total molar number of the hydroxy group in a reaction system, “B” representing the molar number of acetic anhydride to be added, and “C” representing the molar number of water present in the reaction system prior to addition of acetic anhydride; (3) acetylation; (4) melt polymerization; and (5) solid-phase polymerization.

Abstract: Provided are a aromatic liquid crystalline polyester resin having improved low temperature processability, a film having excellent gas barrier property. The aromatic liquid crystalline polyester resin is obtained from an aromatic hydroxycarboxylic acid, an aromatic dicarboxylic acid and an aromatic diol, by optimizing formulation ratio of the above-described three components. The aromatic liquid crystalline polyester resin comprises an aromatic hydroxycarboxylic acid unit, an aromatic dicarboxylic acid unit and an aromatic diol unit, as repeating units, wherein the repeating unit (A) as an aromatic hydroxycarboxylic acid unit, is contained in an amount of 30 mol % or more based on the total amount of repeating units, and the polyester has a logarithmic viscosity of 1.5 dl/g or more, a flow temperature of 300° C. or less, and a melt tension measured at a temperature higher than the flow temperature by 25° C. or more of 1.

Abstract: A branched polyester resin of the Formula wherein n and m represent randomly repeating segments, and the number of n and m segments in the polymer backbone are each of from about 10 to about 10,000; X is an alkylene group, an olefinic group, or an arylene; Y is an organic dioxy group or radical of I, II, or mixtures thereof; Z is an organic trioxy radical of III, IV, or mixtures thereof; and wherein R and R1 is a hydrogen atom or an alkyl group; G is an alkylene or arylene group, and a is 0 or 1.

Abstract: Disclosed are polyester pellets made of a polyester which comprises dicarboxylic acid constituent units derived from dicarboxylic acids containing terephthalic acid and isophthalic acid and diol constituent units derived from diols containing ethylene glycol and 1,3-bis(2-hydroxyethoxy)benzene, and which has the properties: constituent units derived from terephthalic acid are 15 to 99.5 % by mol and constituent units derived from isophthalic acid are 0.5 to 85 % by mol, both based on the total amount of dicarboxylic acid isophthalic acid constituent units (i); constituent units derived from ethylene glycol are 25 to 99.5 % by mol and constituent units derived from 1,3-bis(2-hydroxyethoxy)benzene are 0.5 to 75 % by mol, both based on the total amount of the diol constituent units (ii); the intrinsic viscosity is in the range of 0.5 to 1.5 dl/g; and the melting point (Tm (° C.)), as measured by a differential scanning calorimeter, satisfies the formula [1/527-0.

Abstract: A method of producing a thermotropic liquid crystalline copolyester having an extremely small amount of out-gases comprising the steps of: (1) charging in a reactor 5-100 mol % of aromatic hydroxycarboxylic acid, 0-47.5 mol % of aromatic dicarboxylic acid and 0-47.5 mol % of aromatic diol, so that the sum of mol % of each material is 100 mol % and the mol % of aromatic dicarboxylic acid and that of aromatic diol are substantially equal; (2) adding acetic anhydride of an amount which satisfies the formula, (B−C)/A≧1.04, “A” representing the total molar number of the hydroxy group in a reaction system, “B” representing the molar number of acetic anhydride to be added, and “C” representing the molar number of water present in the reaction system prior to addition of acetic anhydride; (3) acetylation; (4) melt polymerization; and (5) solid-phase polymerization.

Abstract: Thermally stable polymers comprising resorcinol arylate chain members are prepared using an interfacial method comprising the steps of: (a) combining at least one resorcinol moiety and at least one catalyst in a mixture of water and at least one organic solvent substantially immiscible with water; and (b) adding to the mixture from (a) at least one dicarboxylic acid dichloride while maintaining the pH between 3 and 8.5 through the presence of an acid acceptor, wherein the total molar amount of acid chloride groups is stoichiometrically deficient relative to the total molar amount of phenolic groups.

Abstract: A method for producing a copolymerized polyester resin, which comprises subjecting a dicarboxylic acid component containing terephthalic acid or its ester derivative as the main component and a phenylene dioxydiacetic acid as a copolymerizable component, and a diol component containing ethylene glycol as the main component, to polycondensation through an esterification reaction or a transesterification reaction, wherein the phenylene dioxydiacetic acid is added to the reaction system in the form of a solution dissolved in the diol component.

Abstract: Resinous compositions, especially synthetic resins and most especially arylate polymers, contain 2,3-dicyano-1,4-diaminoanthraquinone as a blue dye. Said compositions are characterized by improved weatherability in comparison with compositions containing other blue dyes.

Abstract: A 1,3-propanediol-based aromatic polyester such as polytrimethylene terephthalate is modified by reaction with a hindered phenolic acid or ester to provide an endcapped polyester which has improved resistance to generation of acrolein when heated in air.

Abstract: A method for producing a copolymerized polyester resin, which comprises subjecting a dicarboxylic acid component containing terephthalic acid or its ester derivative as the main component and a phenylene dioxydiacetic acid as a copolymerizable component, and a diol component containing ethylene glycol as the main component, to polycondensation through an esterification reaction or a transesterification reaction, wherein the phenylene dioxydiacetic acid is added to the reaction system in the form of a solution dissolved in the diol component.

Abstract: Process for producing highly stretchable, amorphous anisotropic melt-forming polymers having recurring units derived from p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, at least one aromatic diacid and at least one aromatic diol and/or hydroxyamine component, at least a portion of which is 4,4′-biphenol, which process comprises incorporating into such polymers recurring units derived from one or more aromatic monomers that provide the polymers with selected meta-linkages wherein each of said recurring units is present in the polymer in specific amounts.

Abstract: Process for producing highly stretchable, amorphous anisotropic melt-forming polymers consisting essentially of recurring units derived from p-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, an aromatic diacid, at least a portion of which comprises 2,6-naphthalene dicarboxylic acid, and an aromatic diol and/or hydroxyamine component, at least a portion of which is 4,4′-biphenol; which comprises incorporating into such polymers recurring units derived from resorcinol, wherein each of said recurring units is present in the polymer in specified amounts.

Abstract: A method of producing an aromatic polyester by distilling a low-boiling fraction from a polycondensation vessel containing a reaction product obtained by acetylating raw monomers of the aromatic polyester with acetic anhydride, wherein the polycondensation vessel is provided with a partial condenser, and controlling a temperature of the low-boiling fraction distilled from the partial condenser within a range from 80 to 150° C. while the amount of the low-boiling fraction distilled from the partial condenser is within a range from 50% to 90% based on a theoretical recovery amount is provided; and according to this method, adhesion of low-molecular compounds to a partial condenser in the production can be prevented and an improvement in yield of the aromatic polyester and stabilization of product quality can be accomplished.