Abstract: Described are graphic art films comprising a polyester compositions comprising at least one polyester, comprising dicarboxylic acid component comprising 70 to 100 mole % of terephthalic acid residues and a glycol component comprising: 20 to 30 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues and 70 to 80 mole % of 1,4-cyclohexanedimethanol residues, wherein the total mole % of the dicarboxylic acid component is 100 mole %, the total mole % of the glycol component is 100 mole %, and polyester has following properties: the inherent viscosity of the polyester is from 0.60 to 0.75 dL/g; Tg of from 100 to 130° C.; notched Izod impact strength of at least 7.5 ft-b/inch at 23° C. according to ASTM D256; the melt viscosity of the polyester is less than 10,000 poise as measured at 1 radian/second on a rotary melt rheometer at 290° C.; and the polyester composition contains no polycarbonate.

Abstract: Described are glass laminates comprising polyester compositions comprising polyesters which comprise (a) a dicarboxylic acid component having terephthalic acid residues; optionally, aromatic dicarboxylic acid residues or aliphatic dicarboxylic acid residues or ester residues thereof; 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and 1,4-cyclohexanedimethanol residues.

Abstract: Described are baby bottle(s) comprising polyesters comprising (a) a dicarboxylic acid component having terephthalic acid or an ester thereof; optionally, an aromatic dicarboxylic acid or aliphatic dicarboxylic acid or esters thereof; 2,2,4,4-tetramethyl-1,3-cyclobutanediol; and 1,4-cyclohexanedimethanol.

Abstract: Sulfonated aliphatic-aromatic polyester compositions having improved thermal properties and biodegradability, and articles such as films, coatings and laminates, produced from the sulfonated aliphatic-aromatic polyester compositions, are provided.

Abstract: Described are skylights comprising polyester compositions comprising polyesters which comprise (a) a dicarboxylic acid component having terephthalic acid residues; optionally, aromatic dicarboxylic acid residues or aliphatic dicarboxylic acid residues or ester residues thereof; 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and 1,4-cyclohexanedimethanol residues.

Abstract: Described are film(s) and/or sheet(s) comprising polyesters comprising (a) a dicarboxylic acid component having terephthalic acid residues; optionally, aromatic dicarboxylic acid residues or aliphatic dicarboxylic residues; 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and 1,4-cyclohexanedimethanol residues.

Abstract: A bioderived plasticizer for biopolymers includes a compatibilizing unit and a polyester plasticizing unit. The plasticizer improves the flexibility of biopolymers while not adversely affecting their modulus. The compatibilizing unit renders the plasticizer more miscible with the desired base biopolymer and includes a lower alkyl (C3 to C7) organic acid. The polyester plasticizing unit is formed from monomers comprising a multifunctional alcohol and an aliphatic anhydride or its equivalent dicarboxylic acid and ester derivatives. The polyester plasticizing unit may optionally include one or more difunctional alcohols in combination with the multifunctional alcohol. The resulting the bioderived plasticizer has a low glass transition temperature (Tg), preferably between ?20° C. to 30° C. The plasticizer is preferably amorphous.

Abstract: Described are appliance parts comprising polyester compositions comprising polyesters which comprise (a) a dicarboxylic acid component having terephthalic acid residues; optionally, aromatic dicarboxylic acid residues or aliphatic dicarboxylic acid residues or ester residues thereof; 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and 1,4-cyclohexanedimethanol residues.

Abstract: Described are thermoformed films or sheets comprising polyester compositions comprising polyesters which comprise (a) a dicarboxylicacidcomponent having terephthalic acid or an ester thereof; optionally, an aromatic dicarboxylic acid or aliphatic dicarboxylic acid or esters thereof; 2,2,4,4-tetramethyl-1,3-cyclobutanediol; and 1,4-cyclohexanedimethanol.

Abstract: Described are restaurant smallware comprising polyester compositions comprising polyesters which comprise (a) a dicarboxylic acid component having terephthalic acid residues; optionally, aromatic dicarboxylic acid residues or aliphatic dicarboxylic acid residues or ester residues thereof; 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and 1,4-cyclohexanedimethanol residues.

Abstract: Described are outdoor signs comprising polyester compositions comprising polyesters which comprise (a) a dicarboxylic acid component having terephthalic acid residues; optionally, aromatic dicarboxylic acid residues or aliphatic dicarboxylic acid residues or ester residues thereof; 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and 1,4-cyclohexanedimethanol residues.

Abstract: Described are LCD films or sheets comprising polyester compositions comprising polyesters which comprise (a) a dicarboxylic acid component having terephthalic acid residues; optionally, aromatic dicarboxylic acid residues or aliphatic dicarboxylic acid residues or ester residues thereof; 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and 1,4-cyclohexanedimethanol residues.

Abstract: Described are point of purchase displays comprising polyester compositions comprising polyesters which comprise (a) a dicarboxylic acid component having terephthalic acid residues; optionally, aromatic dicarboxylic acid residues or aliphatic dicarboxylic acid residues or ester residues thereof; 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and 1,4-cyclohexanedimethanol residues.

Abstract: Described are vending machine display panels comprising polyester compositions comprising polyesters which comprise (a) a dicarboxylic acid component having terephthalic acid residues; optionally, aromatic dicarboxylic acid residues or aliphatic dicarboxylic acid residues or ester residues thereof; 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and 1,4-cyclohexanedimethanol residues.

Abstract: Described are intravenous components comprising polyester compositions comprising polyesters which comprise (a) a dicarboxylic acid component having terephthalic acid residues; optionally, aromatic dicarboxylic acid residues or aliphatic dicarboxylic acid residues or ester residues thereof; 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and 1,4-cyclohexanedimethanol residues.

Abstract: Described are blood therapy containers comprising polyester compositions comprising polyesters which comprise (a) a dicarboxylic acid component having terephthalic acid residues; optionally, aromatic dicarboxylic acid residues or aliphatic dicarboxylic acid residues or ester residues thereof; 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and 1,4-cyclohexanedimethanol residues.

Abstract: Described are bottles comprising polyester compositions comprising polyesters which comprise (a) a dicarboxylic acid component having terephthalic acid residues; optionally, aromatic dicarboxylic acid residues or aliphatic dicarboxylic acid residues or ester residues thereof; 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and 1,4-cyclohexanedimethanol residues.

Abstract: Described are polyesters comprising (a) a dicarboxylic acid component comprising terephthalic acid residues; optionally, aromatic dicarboxylic acid residues or aliphatic dicarboxylic acid residues; 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues; and 1,4-cyclohexanedimethanol residues. The polyesters may be manufactured into articles such as fibers, films, bottles or sheets.

Abstract: Disclosed is an oxygen-absorbing resin which exhibits excellent oxygen absorption performance even in the absence of a transition metal catalyst. Specifically disclosed is an oxygen-absorbing resin which is composed of a copolyester obtained by copolymerizing at least the following monomers (A)-(C).

Abstract: Oxygen-scavenging polyester compositions are disclosed that include residues of one or more unsaturated diols having from 4 to 8 carbon atoms, in an amount from about 0.01 mole percent to about 10 mole percent, and residues of terephthalic acid in an amount of at least 50 mole percent, in each case based on the total amount of residues of dicarboxylic acids in the polyester composition comprising 100 mole percent. The polyester compositions typically have an intrinsic viscosity that is at least 0.65 dL/g.

Abstract: A heat-shrinkable polyester film comprising a polyester base film and a coat layer formed on one or both sides of the polyester base film, said coat layer comprising a copolymerised polyester having carboxyl group terminals and Tg in the range of 70 to 80;É, exhibits superior properties suitable for labeling or shrink-wrapping containers.

Abstract: An aqueous dispersion based on an amorphous unsaturated polyester resin obtained by polycondensing a mixture of Dicidol isomers and one or more saturated and/or unsaturated dicarboxylic acids.

Abstract: The strength of wood composites, including hybrid composites comprising wood members bonded to reinforced polyester members, is improved by modifying the polyester components with a polyisocyanate. Wood composites adhesively bonded with polyester resins modified according to this invention are particularly desirable for use in applications where exterior exposure is contemplated.

Abstract: A crystalline polyester obtained by polycondensing monomers comprising 0.1 to 10% by mol of a divalent aromatic compound, wherein the crystalline polyester has a softening point of 85° to 150° C. The crystalline polyester can be suitably used for a resin binder for toner for electrophotography and the like used for developing electrostatic latent images formed in electrophotography, electrostatic recording method, electrostatic printing, and the like; a polyester resin composition comprising the crystalline polyester.

Abstract: A high performance UPR (unsaturated polyester resin) is disclosed. The UPR comprises recurring units of phthalic anhydride, 2-methyl-1,3-propanediol, and maleic anhydride. It has a fumarate/maleate ratio 85/15 or greater. It has a bi- or multi-modal molecular weight distribution. A high molecular weight portion of the UPR has a peak molecular weight (Mp) 50,000 or greater. It has a weight average molecular weight (Mw) 15,000 or greater. An ortho UPR of the invention performs as well as or better than traditional iso UPR.

Abstract: A low tack, low VOC gel coat is disclosed comprising a unsaturated polyester resin derived from maleic anhydride and up to about 30% of an organic solvent. The resin is characterized by: a viscosity of less than or equal to about 1750 cp at 70% NVM in styrene; a glass transition temperature greater than or equal to about 11° C.; and a weight average molecular weight less than or equal to about 6,050. A process for making such a gel coat is also disclosed.

Abstract: The present invention improves the effectiveness of the oxygen scavenging composition and maintains an excellent balance in the color properties of the polymer. The present invention relates to an improved oxygen scavenging PET based copolymer comprising from about 10 to about 120 ppm cobalt based on the PET polymer, and from about 15 to about 150 ppm zinc based on the PET polymer. The present invention also comprises a process for preparing a PET based oxygen scavenging copolymer, comprising the steps of: a) polymerizing a PET based polymer; b) adding Zn, Co, and an oxygen scavenging compound during said polymerizing step; c) copolymerizing said oxygen scavenging compound with said PET based polymer to form a copolymer; and d) extruding said copolymer.

Abstract: A practical polymerizable unsaturated polyester resin composition is provided, wherein a polyester skeleton derived from collected PET is introduced, for effective utilization of waste PET such as a PET bottle which has recently been considered a large obstacle to environmental protection. The polymerizable unsaturated polyester resin composition comprises a straight-chain polyester (A) having a (meth)acryloyl group at both ends of molecules and an ethylenically unsaturated monomer (B), said straight-chain polyester (A) having a (meth)acryloyl group at both ends of molecules being obtained by reacting: (a) a terephthalate oligomer having a hydroxyl group at both ends of molecules resulted from the alcoholysis reaction of collected waste polyethylene terephthalate by an aliphatic glycol having an ether bond, (b) a dibasic acid containing an aromatic dibasic acid as a principal component, and (c) a glycidyl meth)acrylate.

Abstract: Aromatic poly(1,3,4-heterodiazoles) include from 100 to 1,000 repeating units selected from the group consisting of in which R1, R2, R3 and R4 may be identical or different and are each an alkyl, alkoxy, phenyl, phenoxy or thiophenol group and X is S, O or N-phenyl, for use in optical devices, especially electroluminescent components.

Abstract: To provide a novel polyhydroxyalkanoate and a mnaufacturing method by a microorganism capable of substantially reducing unintended inonomer units and obtaining the polyhydroxaykanoate in a high yield. A microorganism capable of synthesizing a novel polyhydroxyalkanoate having 3-hydroxy-substituted benzoylalkanoic acid as a monomer unit using a substituted benzoylalkanoic acid as a material is cultured in tha medium containing a substituted benzoylalkanoic acid, then the polyhydroxyalkanoate produced in the cultured bacteria is extracted and recovered.

Abstract: The invention relates to a powder paint composition comprising a polymer that contains endomethylene tetrahydrophthalic acid units and a crosslinker. The polymer is obtained by preparing an unsaturated polymer in a first step, which then reacts with cyclopentadiene at a temperature between 160 ° C and 220 ° C in a second step. The polymer preferably contains more than 10 wt.% endomethylene tetrahydrophthalic acid units and is preferably an unsaturated polymer.

Abstract: Biodegradable polyesters P1 obtainable by reaction of a mixture consisting essentially of(a1) a mixture consisting essentially offrom 35 to 95 mol % of adipic acid or ester-forming derivatives thereof or mixtures thereof,from 5 to 65 mol % of terephthalic acid or ester-forming derivatives thereof or mixtures thereof, andfrom 0 to 5 mol % of a sulfonate compound, the sum of the individual mole percentages being 100 mol %, and(a2) a dihydroxy compound selected from the group consisting of C.sub.2 -C.sub.6 -alkanediols and C.sub.5 -C.sub.10 -cycloalkanediols,the molar ratio of (a1) to (a2) being chosen within the range from 0.4:1 to 1.5:1,with the proviso that the polyesters P1 have a molecular weight (M.sub.n) within the range from 5000 to 50,000 g/mol, a viscosity number within the range from 30 to 350 g/ml (measured in 50:50 w/w o-dichlorobenzene/phenol at a concentration of 0.5% by weight of polyester P1 at 25.degree. C.) and a melting point within the range from 50 to 170.degree. C.

Abstract: The current invention relates to an alkyd resin particularly useful in high-solids coating compositions. The alkyd resin comprises the reaction product of an unsaturated fatty acid, a polyol, and the adduct of an .alpha.,.beta.-unsaturated dicarboxylic acid to an unsaturated fatty acid wherein the resin containsa) about 5 to about 40 weight % of the adduct of an .alpha.,.beta.-unsaturated dicarboxylic acid to an unsaturated fatty acid,b) about 50 to about 90 weight % of an unsaturated fatty acid which is not part of an adduct,c) about 8 to about 18 weight % of a polyol free from carboxylic groups,d) about 1 to about 30 weight % of an at least two hydroxyl groups-containing monocarboxylic acid,e) optionally, up to about 10 weight % of a dicarboxylic and/or a tricarboxylic acid, andf) optionally, up to 15 weight % of one or more monomers other than the monomers (a) through (e).Also disclosed is their use in coating compositions, particularly high-solids coating compositions having a VOC of less than 170.

Abstract: A cement retarder which comprises a saturated or unsaturated polyester obtained by a reaction of a polycarboxylic acid component comprising a polycarboxylic acid having 2 to 6 carbon atoms in the main chain or its derivative, and a polyol component containing a polyhydric alcohol having 2 to 4 carbon atoms or its condensate, wherein:(a) the saturated polyester has a weight average molecular weight of about 300 to about 50,000; or(b) the unsaturated polyester has a weight average molecular weight of about 500 to about 25,000; or(c) the polyhydric alcohol used to obtain the saturated or unsaturated polyester is a condensate of a C.sub.2-4 alkylene glycol; or(d) the saturated polyester is a polyester obtained by the use of a condensate of a C.sub.2-4 alkylene glycol and has a weight average molecular weight of about 300 to about 50,000; or(e) the unsaturated polyester is a polyester obtained by the use of a condensate of a C.sub.

Abstract: Linear, tertiary carboxyl functional polyester resins obtainable by reaction ofa) at least one compound A.sub.1, comprising the reaction product of(i) a glycidylester of a mixture of certain highly branched saturated monocarboxylic acids isomers, and(ii) a mixture of said highly branched saturated monocarboxylic acids;b) at least one aromatic or cycloaliphatic dicarboxylic acid compound B;c) optionally at least one dihydroxymonocarboxylic acid compound C; andd) optionally at least one diol compound D; in a certain molar ratio of compounds A.sub.1 :B:C:D, at a temperature of from 100.degree. to 225.degree. C., until essentially all the non-tertiary carboxyl groups as initially present in the reaction mixture have been reacted.

Abstract: New compounds including bis-.beta.-hydroxy ethyl bibenzoate containing less than 2.5%, and preferably less than 1%, diethylene glycol and a process for the production of the bis-.beta.-hydroxy ethyl bibenzoate by the condensation of 4,4'-biphenyl dicarboxylic acid and ethylene glycol at low temperature and pressure in the presence of a catalyst are disclosed. Use of the compounds to produce polyesters is also disclosed.

Abstract: New copolymers of recycled polyesters having improved properties are disclosed. The copolyesters are produced by a reaction of recycled polyalkylene terephthalate and a dicarboxylate moiety.

Abstract: Provided is a biaxially oriented, unidirectionally long polyethylene-2,6-naphthalenedicarboxylate film having the following characteristic properties;(A) both the Young's modulus in the longitudinal direction and the Young's modulus in the transverse direction are at least 600 kg/mm.sup.2, and the Young's modulus in the longitudinal direction is greater than the Young's modulus in the transverse direction,(B) the heat shrinkage factor in the transverse direction when the film has been treated under no load at 105.degree. C. for 30 minutes is at least 1%, and(C) the surface roughness Ra of one surface of the film is up to 5 nm, anda magnetic recording tape obtained by forming a thin magnetic metal film on the above film undergoes no curling, has high coercive force, has excellent electromagnetic conversion characteristic and permits high-density recording for a long period of time.

Abstract: New polyesteramides having glass transition temperatures (Tg's) of up to 130.degree. C. and heat deflection temperatures that are in the 100.degree. C. to 110.degree. C. range are disclosed. The new polyesteramides of this invention are made by sequential addition of selected diamines to the diacid/glycol melt. The polyesteramides comprise:--?--A--G--!.sub.x --?--A--NH--R--NH--!.sub.y --wherein A is an organic dicarboxylic acid; G is a glycol selected from linear aliphatic diols and cycloaliphatic diols having 5 to 20 carbon atoms; R is selected from alkyl, cycloalkyl, arylkyl, or aryl; and x and y are whole numbers having an x/y ratio between about 9 to about 0.5 and sum of X and Y is from about 2 to about 500.

Abstract: Provided is a biaxially oriented, unidirectionally long polyethylene-2,6-naphthalenedicarboxylate film having the following characteristic properties;(A) both the Young's modulus in the longitudinal direction and the Young's modulus in the transverse direction are at least 600 kg/mm.sup.2, and the Young's modulus in the longitudinal direction is greater than the Young's modulus in the transverse direction,(B) the heat shrinkage factor in the transverse direction when the film has been treated under no load at 105.degree. C. for 30 minutes is at least 1%, and(C) the surface roughness Ra of one surface of the film is up to 5 nm, anda magnetic recording tape obtained by forming a thin magnetic metal film on the above film undergoes no curling, has high coercive force, has excellent electromagnetic conversion characteristic and permits high-density recording for a long period of time.

Abstract: Carboxyl-terminated polyesters comprising the reaction products of(a) an aliphatic hydroxyl-terminated polyester prepared from 1,4-cyclohexanedicarboxylic acid and an alcohol component comprising(1) from 10 to 100 equivalent % of a cycloaliphatic diol and(2) from 90 to 0 equivalent % of a straight or branched chain aliphatic polyol having 2 to 12 carbon atoms, with(b) an aliphatic and/or aromatic dicarboxylic acid or the corresponding anhydride,process for preparing the same and the thermosetting powder compositions based on these polyesters and polyepoxy compounds used for the production of powder varnishes and paints. These polyesters provide coatings having an excellent weatherability combined with outstanding mechanical properties, even if curing takes place at low temperature.

Abstract: The present invention provides a powder coating composition which is suitable for precoated steel plates. The powder coating composition has excellent storage stability (e.g. blocking resistance) and provides a cured film having good weather resistance and a good balance of hardness and processability. The powder coating composition comprises;(I) 95 to 70% by weight of a polyester resin having a glass transition temperature of 40.degree. to 70.degree. C., prepared from (i) and acid component containing at least 80 mole % of an aromatic dicarboxylic acid with (ii) a polyol component which comprises(a) at least 50 mole % of neopentyl glycol, and(b) 1 to 10% by weight of a diol selected from the group consisting of a linear chain C.sub.8 -C.sub.16 alkylene diol, 2-methyl-1,8-octane diol and a mixture thereof, and(II) 5 to 30% by weight of a curing agent.

Abstract: Copolyester compositions are provided which comprise the reaction product of at least one straight chain, branched, or cycloaliphatic C.sub.2 -C.sub.10 alkane diol or a chemical equivalent thereof, a mixture of at least two cycloaliphatic diacids or chemical equivalents thereof, the mixture comprising predominantly a trans-enantiomer, and at least one aromatic diacid or a chemical equivalent thereof. These copolyesters have superior ductility to the homopolymers of the diol component and either of the diacid components.

Abstract: Carboxyl group-terminated polyesteramides comprising the reaction products of at least one diamine and a carboxyl group-terminated polyester selected from(a) a polyester prepared from at least one aliphatic and/or cycloaliphatic dicarboxylic acid and at least one polyol:(b) a polyester which is the reaction product of(i) at least one aliphatic and/or cycloaliphatic dicarboxylic acid and/or isophthalic acid, with(ii) a hydroxyl group-terminated polyester, and(c) a polyester which is the reaction product of(i) at least one aliphatic and/or cycloaliphatic dicarboxylic acid, with(ii) a polyester containing both terminal hydroxyl and terminal carboxyl groups, prepared by esterification of(iii) isophthalic acid with(iv) a hydroxyl group-terminated polyester,processes for preparing the same, and the powdered thermosetting compositions based on these polyesteramides and polyepoxy compounds for the production of powdered varnishes and paints which can be applied with a triboelectric spray gun.

Abstract: A crosslinked poly(ethylene or propylene)glycol-containing polymer which has a unique spatial structure and can be designed especially for application as a chromatographic resin or as a solid support for the synthesis of peptides, oligonucleotides or oligosaccharides or as a substrate for the immobilization of proteins. The polymer is formed by radical copolymerization of derivatized poly(ethylene or propylene) glycol bis-end substituted with a moiety selected from the group consisting of acryloylalkyl, acryloylaryl, acrylamidoalkyl and acrylamidoaryl with an acrylic amide, nitrile or ester. When it is to be used as a solid support or immobilization substrate, the polymer will incorporate a spacer comprising functional groups for the attachment of peptides, proteins, nucleotides or saccharides such as those selected from the group consisting of amino, alkylamino, hydroxy, carboxyl, mercapto, sulfeno, sulfino, sulfo and derivatives thereof.

Abstract: A new melt viscosity depressant for a polyester resin having a structure of an aromatic carbonyl compound is disclosed.Addition of the melt viscosity depressant to a polyester resin reduces the melt viscosity of the resin remarkably, thereby facilitating mold processing and melt-spinning of the polyester resin composition, from which high strength polyester molding products and polyester fibers can be obtained.

Abstract: Carboxyl group-terminated polyesteramides comprising the reaction products of at least one diamine and a carboxyl group-terminated polyester selected from(a) a polyester prepared from at least one aliphatic and/or cycloaliphatic dicarboxylic acid and at least one polyol;(b) a polyester which is the reaction product of(i) at least one aliphatic and/or cycloaliphatic dicarboxylic acid and/or isophthalic acid, with(ii) a hydroxyl group-terminated polyester, and(c) a polyester which is the reaction product of(i) at least one aliphatic and/or cycloaliphatic dicarboxylic acid, with(ii) a polyester containing both terminal hydroxyl and terminal carboxyl groups, prepared by esterification of(iii) isophthalic acid with(iv) a hydroxyl group-terminated polyester,processes for preparing the same, and the powdered thermosetting compositions based on these polyesteramides and polyepoxy compounds for the production of powdered varnishes and paints which can be applied with a triboelectric spray gun.

Abstract: Hard resinous polyol esters having a high degree of hydroxyl functionality and a ball and ring softening temperature of at least about 50.degree. C.

Abstract: The invention is concerned with novel water-dispersible copolymers which contain at least one UVA light-absorbing monomer, one UVB light-absorbing monomer, one hydrophilic monomer, and optionally one hydrophobic monomer component. The UVA light-absorbing monomer absorbs at .lambda.max ultraviolet light in the 320-400 nm range. The UVB light-absorbing monomer absorbs at max ultraviolet light in the 290-320 nm range. Because of the R.sub.3 group used in the invention, the copolymers of the invention permit higher loading of UV monomers than previously obtainable.

Abstract: A biaxially oriented polyester film simultaneously satisfying the following formulas (I) to (III):.vertline.S.sub.180 -S.sub.120 .vertline..ltoreq.54 (I)T.sub.S.sup.MD .gtoreq.100 (II)Q.sub.120 .ltoreq.0.7 (III)wherein S.sub.180 is shrinking stress (g/mm.sup.2) of the film in the machine direction at 180.degree. C., S.sub.120 is shrinking stress (g/mm.sup.2) of the film in the machine direction at 120.degree. C., T.sub.S.sup.MD is shrinkage initiation temperature (.degree.C.) of the film in the machine direction, and Q.sub.120 is shrinkage (%) of the film in the machine direction after 5 hours' treatment at 120.degree. C., is described. The film has a good dimensional stability due to its low shrinkage, particularly in the machine direction, and substantially free from defect such as wave and wrinkle.It is prepared by biaxially stretching, heat-setting and relaxing an extruded polyester film under particular conditions so as to obtain a biaxially oriented polyester film having these characteristics.