Abstract: A cationic dye-dyeable polyester resin composition comprising a cationic dye-dyeable polyester resin and a melt viscosity depressant.Addition of the melt viscosity depressant to the cationic dye-dyeable polyester resin reduces the melt viscosity of the resin without decreasing the intrinsic viscosity thereby making the resin melt-spinnable. A cationic dye-dyeable polyester fiber with high strength can be obtained from the polyester resin composition.

Abstract: An aromatic polyestersulfone having improved heat resistance, film-forming property, hydrolysis resistance and mechanical strength which comprises 1 to 100% by mole of recurring units of the general formula: ##STR1## and 99 to 0% by mole of recurring units of the general formula: ##STR2## wherein R and R' are the same or different and each is an alkyl or alkoxyl group having 1 to 4 carbon atoms, Ar is a bivalent aromatic group, and x and y are 0 or an integer of 1 to 4 provided that the sum of x and y is from 1 to 8.

Abstract: Tough, high strength fibers of copolyesters from hydroquinone, isophthalic acid and 4,4'-oxydibenzoic acid in defined proportions.

Abstract: The invention relates to thermotropic liquid crystalline polymer compositions of the general formula:--(CO--C.sub.6 H.sub.4 O).sub.m --(CO--C.sub.6 H.sub.4 --CO).sub.n--(O--C.sub.6 H.sub.4 --X).sub.p --(O--C.sub.6 H.sub.4 --C(CH.sub.3).sub.2 --C.sub.6 H.sub.4 --O).sub.q --(O--C.sub.6 H.sub.4 --S--C.sub.6 H.sub.4 --O).sub.t --where substantially all aromatic substituents are para to one another, where--X-- can be either --O-- or --NH--, andm, n, p, q and t are mole fractions totaling 1.0,wherem is 0 to 0.75,m plus 2p is 0.5 to 0.75,n is 0.125 to 0.5,p is 0 to 0.375,q is 0.125 to 0.25,n equals p plus q plus t, andt is greater than 0.0125, but equal to no greater than 90% of q plus t.Preferably X is --O--, m is from 0.5 to 0.75 and p is less than 0.05. Alternatively, m is less than 0.1 and p is from 0.25 to 0.375.

Abstract: The present invention discloses a wholly aromatic, melt processable polyester which is comprised of recurring moieties derived from the following compounds: 2,6-naphthalenedicarboxylic acid, 4-hydroxybenzoic acid, an aromatic dihydroxy compound, and 6-hydroxy-2-naphthoic acid. The resulting wholly aromatic polyester is capable of forming a thermotropic melt phase at temperatures below approximately 350.degree. C. and most preferably at temperatures below approximately 290.degree. C.

Abstract: Polyesters are prepared from dihydroxyl-containing compounds and di-carboxylic acids or anhydrides or lower alkyl esters thereof in the presence of a combination of tin catalysts comprising (1) at least one organotin salt of a carboxylic acid, and (2) either (a) at least one organotin oxide, or (b) at least one organostannoic acid, or (c) a combination of (a) and (b). The polyesters prepared by this process are useful in coating, adhesive, fiber and molding applications.

Abstract: Flame-resistant thermoplastic branched polycarbonates of high molecular weight are prepared from:(1) a carbonate precursor;(2) at least one dihydroxyaromatic compound of formula: ##STR1## where: R is a single bond, or a substituted or non-substituted linear or branched C.sub.1 -C.sub.5 alkylene radical, or a group chosen from O, S, SO.sub.2 and CO;X and Y, which may be the same or different, are H or CH.sub.3 ;m and n, which may be the same or different, are whole numbers from 1 to 4;(3) at least one halogenated pyrimidine compound of formula: ##STR2## where: R.sub.2, R.sub.3, R.sub.4, which may be the same or different, are chlorine or bromine or hydrogen, on condition that at least one is chlorine or bromine;R.sub.1 is chlorine or bromine, or a radical of formula: ##STR3## where Z is NH or S or O; (4) at least one polyfunctional organic compound as branching agent, characterized by possessing at least three equal or different groups chosen from the groups OH, COOH, COCl and SO.sub.2 Cl.

Abstract: A process for preparing polyarylates having low color wherein isophthalic acid, terephthalic acid, and bisphenol A are melt polymerized to form a prepolymer, the prepolymer is crystallized, and then further polymerized in the solid state by heating under an inert gas flow, e.g. nitrogen. Crystallization is accomplished by adding the amorphous prepolymer in powder or pellet form to a organic crystallizing medium such as 2-ethoxyethyl acetate or hexyl acetate. This process produces a polymer having low color content. The crystallized polymer may be made amorphous by melting. This amorphous polymer is useful in applications requiring a transparent, colorless plastic.

Abstract: New aromatic polyesters and polyester-carbonates are prepared by the reaction of bisphenols of the formula ##STR1## wherein R.sup.3 and R.sup.4 independently of each other represent C.sub.1 -C.sub.4 alkyl group or a halogen atom, i and k denote zero or an integer 1 to 4, and X.sub.1 and X.sub.2 represent fluorine by the two-phase boundary process in an aqueous-alkaline phase with iso- or tere-phthaloyl dichloride. The polyesters and polyester carbonates according to the invention can be processed to form shaped articles by extrusion molding or in an extruder, applied in the form of solutions, or spun to fibers from melt or solution.

Abstract: Bisphenol-based polyesters and a process for their preparation having a first step of diacetylizing the bisphenol then polymerizing the diacetate with an aromatic diacid and an aliphatic diacid are disclosed. The bisphenol-based polyesters can be used as binder components in a charge transport or charge generation layers of an organic photoreceptor.

Abstract: Novel thermotropic semialiphatic copolyesteramides having relatively low melt temperatures contain the following recurring structural units: ##STR1## in which Ar.sub.1 is a divalent aromatic and/or cycloaliphatic radical, Ar.sub.2 is a divalent aromatic radical, X is --NH-- or --CO--, and A includes a divalent aliphatic hydrocarbyl radical.

Abstract: Liquid-crystalline, completely aromatic copolyesters are disclosed, which are endowed with a heat stability not lower than 350.degree. C., and are constituted by a succession of repetitive units containing: ##STR1## wherein A and B, which can be either equal to, or different, from, each other, can be either --O-- or --CO-- and one of the following moieties: ##STR2## in which Ar can be 1,4-phenylene, 2-monosubstituted-1,4-phenylene or 4,4'-diphenylene.Also copolyesters also containing amidic bonding groups are disclosed.

Abstract: A polyester resin comprised of (a) units derived from a terephthalic acid component and/or a isophthalic acid component, (b) 0 to 80 mole %, based on the total carboxylic acid component, of units derived from a diol component represented by the formula: ##STR1## wherein R represents an alkyl group having 2 or 3 carbon atoms, and x and y are integers satisfying the requirement of 2.ltoreq.x+y.ltoreq.6,and (c) 20 to 200 mole %, based on the total carboxylic acid component, of units derived from an aliphatic diol component. The polyester has a weight average molecular weight M.sub.w of 3,000 to 20,000, a number average molecular weight M.sub.n of 1,000 to 10,000, a glass transition temperature T.sub.g of 40.degree. to 70.degree. C., and a softening temperature of 70.degree. to 130.degree. C. The polyester is valuable for a toner.

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.

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. Advantageously, the polymers of the present invention display a significant improvement in viscosity and moldability of the neat polymer. The polymers have excellent mechanical and surface properties including blister resistance, strength, toughness, and ability to vapor phase solder, and form strong fibers while still maintaining a high heat distortion temperature. They have melting points in the range of from about 250.degree. to about 360.degree. C. and are melt-processible. Advantageously, these compositions filled with about 30 weight percent of glass fibers display heat distortion temperatures of up to 240.degree.

Abstract: A copolyesterimide composed of bis-trimellitimide units, 2,6-naphthalenedicarboxylic acid units, hydroquinone units and p-hydroxybenzic acid units. This copolyesterimide is melt-processable, and excels in heat resistance and mechanical properties.

Abstract: An aromatic polyester comprising the repeating units (A), (B), (C) and (D) represented by the following formulae in amounts of 0 to 80 mole %, 10 to 50 mole %, 5 to 50 mole % and 0 to 30 mole %, respectively, having a logarithmic viscosity of 1.0 dl/g or more and capable of being melt-molded at a temperature of 350.degree. C. or less: ##STR1## where R represents a C.sub.2 -C.sub.6 alkylene, and--O--AR--O-- (D)where Ar represents a divalent aromatic residue, and a process for producing the same. The aromatic polyesters according to the present invention combine moldability and heat resistance in a good state and have mechanical properties of sufficient practical value. An aromatic polyester according to the present invention shows optical anisotropy at a molten state.

Abstract: Novel thermotropic polyesters and polyester-amides containing fluorine bearing linking groups are disclosed and claimed. Preferred embodiments include thermotropic polymers prepared from 4-Hydroxybenzoic acid, 6-hydroxy-2 naphthoic acid, 2,2-bis(4-carboxyphenyl)hexafluoropropane, hydroquinone, and terephthalic acid.

Abstract: Thermosettable polyol resins for coating compositions are prepared by reacting a polyglycidyl ester of an aliphatic polycarboxylic acid and a di- to hexa-hydric aliphatic alcohol with an adduct of a di- to hexa-hydric aliphatic alcohol and a glycidyl ester of a branched aliphatic monocarboxylic acid with 5 to 15 C-atoms, said adduct having an epoxy group content of less than 0.2 meq/g.

Abstract: A thermoplastic, liquid-crystalline, wholly aromatic polyimide ester comprising(a) at least one structural unit derived from an aromatic dicarboxylic acid,(b) at least one structural unit derived from a substituted hydroquinone having an aralkyl substitutent group in its benzene nucleus, andat least one structural unit selected from (c) structural units derived from carboxy-N-(carboxyphenyl)phthalimides and (d) structural units derived from carboxy-N-(hydroxyphenyl)phthalimidesis able to be molded by injection molding, has excellent dimensional stability and dimensional accuracy in both flow direction and a direction making a right angle with the flow direction, and is also excels in strength, elastic modulus, and heat resistance.

Abstract: A thermotropic aromatic polyester comprising (a) an aromatic dicarbonyl ingredient comprising recurring aromatic units of the formulae (I) and/or (II): ##STR1## and, optionally, other recurring aromatic dicarbonyl units, (b) an aromatic dioxy ingredient comprising recurring aromatic units of the formula (III) ##STR2## wherein R.dbd.--H, C.sub.

Abstract: A monofunctional alcohol or acid is used to chain stop a condensation reaction for preparing a low molecular weight unsaturated polyester resin. The monofunctional acid removes terminal hydroxy groups and replaces them with hydrocarbon groups. The monofunctional alcohol removes terminal carboxy groups and replaces them with hydrocarbon groups. The resulting polyester resins having improved hydrolytic stability. These chain stopped unsaturated polyester resins can be further modified with hydroxy acrylates, other hydroxy terminated polyesters, and diisocyanates to produce resins with excellent water resistance and physical properties for various applications, such as marble/onyx resins, sheet molding compounds, bulk molding compounds and resin transfer molding resins, gel coats, and bowling ball resins.

Abstract: This invention relates to thermotropic liquid crystalline polyester compositions containing recurring units derived from 2-methylhydroquinone, terephthalic acid, 2,6-napthalenecarboxylic acid, and hydroquinone, characterized as having a heat distortion temperature of greater than 200.degree. C. and improved elongation. The inclusion of a reinforcing/filling agent selected from the group consisting of glass reinforcing agents, glass fillers, carbon metasilicate, calcium carbonate, talc, titanium dioxide, and calcined aluminum silicate in said compositions, and also in those same compositions lacking recurring units of hydroquinone, results in an improvement in the elongation of said compositions. The inclusion of carbon fiber into these compositions results in no significant decrease in the elongation of said compositions. The compositions are useful as films, fibers, and shaped articles.

Abstract: Polyester and polyester carbonates corresponding to the following formula ##STR1## in which R.sup.1 to R.sup.4, o to r, n, a and b and also X.sup.1 and Y.sup.1 are as defined in the specification,may be obtained by interfacial condensation from bisphenols corresponding to the following formula. ##STR2## aromatic dicarboxylic acid chlorides corresponding to the following formula ##STR3## and phosgene. The new polyesters and polyester carbonates combine outstanding heat resistance and light stability. They may be used both as thermoplastic materials as such or as constituents of polymer blends or even as UV (light) stabilizers or as UV (light)-stabilizing coatings. Accordingly, they have degrees of polycondensation n in the range from 2 to 100.

Abstract: This invention provides thermoplastic polymeric materials comprising polycarbonate and polyestercarbonte resins and oriented polymeric compositions thereof which exhibit nonlinear optical properties.

Abstract: Sintered bodies made of aromatic polyesters prepared from diphenols, such as 1,1-bis(4-hydroxyphenyl-1-phenylethane or 9,9-bis(4-hydroxyphenyl)fluorene, and halides of phthalic acid which have one or more glass transition temperatures in the range of 220.degree.-400.degree. C. and tensile strengths higher than 40 N/mm.sup.2, and advantageously higher than 60 N/mm.sup.2 are disclosed. To make the sintered bodies, polyester powder is exposed to high pressure within a closed mold and the temperature of the polyester powder is slowly increased by heating until a temperature higher than the glass transition temperature is reached, whereafter the polyester is slowly cooled. During the sintering process the polyester is crosslinked which results in an increased resistance against solvents. The sintered bodies of the invention are used in general as semi-finished products or preformed parts, which will be transformed to bodies with required shapes through subsequent machining.

Abstract: A high modulus, high strength melt processable copolyester consisting essentially of recurring units (I), (II), (III) and (IV): ##STR1## wherein said copolyester has a melting point in the range of from about 340.degree. C. to 400.degree. C., a crystallization temperature of from about 300.degree. C.-340.degree. C., and a crystallization rate of at least 1,000 counts/minute.

Abstract: A transparent polyester-ester amide having a permanently antistatic property is obtained by copolymerizing (a) an aminocarboxylic acid, a lactam, or a salt derived from a diamine and a dicarboxylic acid; (b) a diol of the formula: ##STR1## wherein R.sup.1 and R.sup.2 are an ethylene oxide or propylene oxide group, Y is covalent bond, alkylene, alkylidene, cycloalkylidene, arylalkylidene, O, SO, SO.sub.2, CO, S, CF.sub.2, C(CF.sub.3).sub.2 or NH, X is H, alkyl, halogen, sulfonic acid or salt thereof, l is 0 or an integer of 1-4, and m and n an integer of 1-15; (c) a poly(alkylene oxide)glycol or a diol of the formula:HO--R.sup.3 --OH (IV)wherein R.sup.3 is alkylene, alkylidene, cycloalkylidene or arylalkylidene; and (d) a dicarboxylic acid; wherein the content of the polyether-ester units is 10 to 90 wt. %.

Abstract: Described herein are novel polyarylates derived from mixtures of terephthalic and isophthalic acids, hydroquinone and 4,4'-dihydroxydiphenyl sulfone. The instant polyarylates exhibit excellent stress-crack resistance in a wide variety of solvents. Moreover, the materials display very good mechanical and thermal properties.

Abstract: In a two-phase interface polycondensation process for preparing aromatic polyesters from diphenols comprising at least in most part a central carbon atom, with groups bound to this carbon atom being hampered in their free rotation, in particular for instance 9,9-bis(4-hydroxyphenyl)fluorene, with dicarboxylic-acid chlorides such as iso-terephthaloyl chloride, the aqueous phase with the diphenolate contains acetone or methylethylketone as the solubilizer, whereas the dicarboxylic-acid chlorides dissolved in a chlorinated hydrocarbon form the organic liquid phase. Compared to known procedures with other solubilizers, for instance isopropanol, in this case polyesters are produced with higher molecular weights. The acetone or methylethylketone also may simultaneously serve as precipitant after the end of polycondensation for the polymer dissolved in the organic liquid phase.

Abstract: A cholesteric liquid crystal polyester high molecular weight polymer has, as structural units, (1) --O--Ar--CO--, (2) camphoric acid, (3) --O--R.sub.1 --O-- and (4) --CO--R.sub.2 --CO--, wherein Ar is a bivalent aromatic ring having 6-12 carbon atoms, and R.sub.1 and R.sub.2 are bivalent aromatic rings having 6-18 carbon atoms, a bivalent aliphatic chain having 2-16 carbon atoms, or a bivalent alicyclic ring having 6-18 carbon atoms. The liquid crystal polyester exhibits high physical properties, including strength and elasticity modulus, with reduced mechanical anisotropy, while exhibiting selective visible light reflection under certain conditions.

Abstract: Aromatic polyesters based on isophthalic acid, terephthalic acid, p-hydroxybenzoic acid, hydroquinone and an arylene diol are described. The five monomers ae used in well-specified proportions and yield polymers that display an excellent overall combination of mechanical and thermal properties. The subject copolyesters have melting points of at least about 260.degree. C.; their heat distortion temperatures are at least about 200.degree. C. they have fiber ratings of up to 3. The novel polymers can be melt-fabricated using standard injection molding, extrusion and melt-spinning techniques.

Abstract: The present invention relates to aromatic compounds corresponding to formula (I) ##STR1## to their production and to their use as modifiers for thermoplastic aromatic polycarbonates and/or thermoplastic aromatic polyester carbonates and/or thermoplastic aromatic polyesters.

Abstract: The present invention relates to aromatic compounds corresponding to formula (I) ##STR1## to their production and to their use as modifiers for thermoplastic aromatic polycarbonates and/or thermoplastic aromatic polyester carbonates and/or thermoplastic aromatic polyesters.

Abstract: The thermotropic, fully aromatic polycondensates according to the invention, which contain compounds capable of complex formation, are distinguished by improved resistance to hydrolysis and may be used for the production of moulded articles, fibres, filaments, sheet products and films.

Abstract: A toner composition comprised of a crosslinked thermotropic liquid crystalline polymer, a branched liquid crystalline polymer, or mixtures thereof.

Abstract: The invention relates to a class of copolymers capable of forming an optically anisotropic melt comprising recurring structural units (a) independently each occurrence selected from the group consisting of Formula I; recurring structural units (b) independently each occurrence selected from the group consisting of Formulas II and III; recurring structural units (c) independently each occurrence selected from the group consisting of Formula IV and optionally recurring structural units (d) independently each occurrence selected from the group consisting of Formula V: ##STR1## wherein R independently each occurrence is a chemically inert substituent.

Abstract: Disclosed is a process for preparation of a polyarylate having a degree of polymerization of at least 50 by polymerizing an admixture comprised of 4-dialkylaminopyridine, an acid anhydride, bisphenol-A and a mixture of isophthalic acid and terephthalic acid by the steps of(1) subjecting the admixture to a pressure in the range of 500 to 1400 mm of Hg and a temperature in the range of 20.degree. to 150.degree. C. while maintaining a degree of polymerization of substantially 1.0,(2) subjecting the admixture to a pressure in the range of 500 to 1400 mm of Hg and a temperature in the range of 285.degree. to 350.degree. C. to achieve a degree of polymerization in the range of 2 to 7,(3) subjecting the admixture to a pressure in the range of 100 to 400 mm of Hg and a temperature in the range of 285.degree. to 350.degree. C. to achieve a degree of polymerization in the range of 7 to 15,(4) subjecting the admixture to a pressure in the range of 100 to 400 mm of Hg and a temperature in the range of 330.degree. to 400.

Abstract: Disclosed is a process for the preparation of poly(ester-carbonates) wherein (1) an aromatic diol, (2) methyl phenyl carbonate and (3) an alkyl carboxylate ester component selected from an aromatic dicarboxylate ester, a hydroxy aromatic carboxylate ester or a mixture thereof are contacted in the presence of a transesterification/polycondensation catalyst under transesterification/polycondensation conditions of pressure and temperature.

Abstract: Wholly aromatic polyesters based on isophthalic acid, terephthalic acid, p-hydroxybenzoic acid, hydroquinone and an arylene diol, e.g. 4,4'-biphenol are described. The materials displayed are excellent overall combination of mechanical and thermal properties. Their melting points and heat distortion temperatures (264 psi) are at least about 260.degree. C. and 260.degree. C., respectively. These novel polymers can be melt-fabricated using standard injection molding, extrusion, and melt spinning techniques and yield fabricated articles with good surface characteristics.

Abstract: A process comprising(A) preparing a solid polyarylate prepolymer having an inherent viscosity of at least about 0.1 by heating at a temperature in the range of 140.degree. C. to 300.degree. C. in the melt phase an acid anhydride derived from a carboxylic acid containing 2 to 6 carbon atoms, a dihydric phenol and an aromatic dicarboxylic acid in the presence of a hypernucleophilic base which comprises a heterocyclic aromatic compound containing nitrogen and having an aprotic electron releasing group directly bonded to a carbon atom in the aromatic compound, and(B) increasing the molecular weight of the solid polyarylate prepolymer to an inherent viscosity of at least 0.4.

Abstract: An aromatic polyester superior in heat resistance and melt-moldability is obtained by carrying out the polycondensation reaction withComponent A consisting of at least one compound having the formula, ##STR1## wherein R.sub.1 is hydrogen, formyl, acetyl, propionyl or benzoyl, and R.sub.2 is hydrogen, a C.sub.1 -C.sub.6 alkyl or a C.sub.6 -C.sub.18 aryl, or a mixture containing not less than 50% by mole of said compound,Component B consisting of at least one compound having any one of the formulas, ##STR2## wherein R.sub.3 is hydroxyl, a C.sub.1 -C.sub.6 alkyloxy, a C.sub.6 -C.sub.18 aryloxy or halogen, or a mixture containing not less than 50% by mole of said compound, andComponent C consisting of at least one compound having the formula,R.sub.4 O--A.sub.1 --OR.sub.4wherein A.sub.1 is a divalent aromatic residue, and R.sub.4 is hydrogen, acetyl, propionyl or benzoylin a reaction vessel at a temperature of 270.degree. C. to 380.degree. C.

Abstract: A wholly aromatic polyester is composed of naphthalene dicarboxylic acid units comprising 5 to 95 mole % of the unit having the formula (1) and 95 to 5 mole % of the unit having the formula (2) and aromatic diol units having the formula (3). It is improved in heat resistance and may be blended with a filler.

Abstract: Provided herein are an aromatic polyester having superior physical properties which is composed of the following units ##STR1## an aromatic polyester amide formed by introducing a prescribed amount of amide linkage into said aromatic polyester; filament thereof; and a composition formed by adding an inorganic filler or magnetic powder to said polymers.

Abstract: A process for extruding a smooth and uniform film or sheet of an ordered poly(ether ketone ketone) having a thickness of about 2.5 to 250 micrometers, wherein the molten extrudate is quenched on a drum maintained at a temperature of about 100.degree.-170.degree. C.

Abstract: A melt-processable copolyester consisting essentially of:a structural unit (I) of formula (1-1) ##STR1## and formula (1-2) ##STR2## wherein the amount of the species of formula (1-2) is 5 to 95 mole % of the structural unit (I),a structural unit (II) of formula (2)--O--X--O-- (2)wherein X is at least one selected from the group consisting of ##STR3## and a structural unit (III) of formula (3)--O--Y--CO-- (3)wherein Y is at least one selected from the group consisting of ##STR4## the proportion of the structural unit (III) being 10 to 80 mole % of the structural units (I)+(II)+(III) in total, the structural unit (I) being substantially equimolar to the structural unit (II) and inherent viscosity (ln .eta..sub.rel)/C, measured in a concentration of 0.16 g/dl in pentafluorophenol at 60.degree. C., being not less than 0.5 dl/g.

Abstract: Aromatic copolyesters comprise 10 to 90 mol % of the repeating unit (I) and 90 to 10 mol % of the repeating unit (II): ##STR1## wherein Y.sup.1 and Y.sup.2 may be the same or different and are, for example, a lower alkylene group, a lower alkylidene group or a carbonyl group, Ar is, for example, a phenylene group or a naphthylene group, and m or n is zero or one, and the copolyesters have high glass transition temperature, heat resistance, modulus, moulding processability and mechanical strength and are useful for shaped articles in mechanical, electrical or medical applications.

Abstract: This invention relates to copolyestercarbonate polymers which are prepared with diaryl dicarboxylic acid compounds, particularly biphenyldicarboxylic acid compounds. Such copolyestercarbonate polymers show good physical properties including high glass transition temperatures and low ultraviolet radiation sensitivity. The thermoplastic copolymestercarbonates can be used to prepare films or molded articles or blended with other thermoplastic resins to give thermoplastic polymer blends for molding purposes.

Abstract: Polyesters and polyester-carbonates based on dihydroxydiphenylcycloalkanes corresponding to the following general formula: ##STR1## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 independently represent hydrogen, a C.sub.1 -C.sub.12 hydrocarbon radical or halogen; m represents an integer of from 4 to 7,R.sup.5, and R.sup.6, may be selected individually for each X and independently represent hydrogen or C.sub.1 -C.sub.6 alkyl; andX represents carbon;with the proviso that, on at least one atom X, R.sup.5 and R.sup.6 simultaneously represent alkyl.

Abstract: A copolyester having an intrinsic viscosity, measured in o-chlorophenol at 25.degree. C., of 0.3 to 1.5 dl/g and being derived from dicarboxylic acid units composed of 95 to 60 mole % of isophthalic acid units and 5 to 40 mole % of 2,6-naphthalenedicarboxylic acid units and dihydroxy compound units composed of 95 to 70 mole % of ethylene glycol units and 5 to 30 mole % of 1,3-bis(2-hydroxyethoxy)benzene units; a gas barrier imparting agent composed of the copolyester; a polyester composition composed of (A) a polyethylene terephthlate and (B) the copolyester; and a film, a preform and a container composed of the polyester composition. Also provided are a polyester laminated structure, a stretched laminated structure, a preform and a laminated blow-molded article each composed of (C) a polyalkylene terephthalate layer and (D) a copolyester layer composed of the copolyester or the polyester composition.