Abstract: Flexible, liquid fillable bottles of polyester resin are provided which have a capacity in liters relative to the weight thereof in grams excluding the neck of from 0.15 to 0.5 and from 0.2 to 1.5 for larger capacities. The bottles are obtained by blowing parisons freely or in a rigid container, the shape of which the bottles assume, said parisons being of polyester resin with suitable rheological properties.

Abstract: Compositions suitable for preparing transparent articles comprising an aromatic polyester resin selected from a copolyalkylene terephthalate containing from 3 to 15% by moles of units derived from isophtalic acid and/or a naphthalene dicarboxylic acid and a polyxylylene amide, preferably poly (m.xylylene adipamide), in which the polyamide is dispersed in the polyester resin as domains with average numeral size of 30 to 200 nm. The compositions are obtained by premelt-mixing the polyester with a dianhydride of a tetracarboxylic acid prior mixing the polyxylylene amide using melt viscosity ratio between the polyester resin and the polyxylylene amide higher than 1.5:1, preferably from 3:1 to 8:1.

Abstract: Compositions suitable for preparing transparent articles comprising an aromatic polyester resin selected from a copolyalkylene terephthalate containing from 3 to 15% by moles of units derived from isophtalic acid and/or a naphtalene dicarboxylic acid and a polyxylylene amide, preferably poly (m.xylylene adipamide), in which the polymide is dispersed in the polyester resin as domains with average numeral size of 30 to 200 nm. The compositions are obtained by premelt-mixing the polyester with a dianhydride of a tetracarboxylic acid prior mixing the polyxylylene amide using melt viscosity ration between the polyester resin and the polyxylylene amide higher that 1.5:1, preferably from 3:1 to 8:1.

Abstract: Compositions suitable for preparing transparent articles comprising an aromatic polyester resin selected from a copolyalkylene terephthalate containing from 3 to 15% by moles of units derived from isophtalic acid and/or a naphtalene dicarboxylic acid and a polyxylylene amide, preferably poly (m.xylylene adipamide), in which the polymide is dispersed in the polyester resin as domains with average numeral size of 30 to 200 nm. The compositions are obtained by premelt-mixing the polyester with a dianhydride of a tetracarboxylic acid prior mixing the polyxylylene amide using melt viscosity ration between the polyester resin and the polyxylylene amide higher that 1.5:1, preferably from 3:1 to 8:1.

Abstract: Flexible, liquid-fillable bottles of polyester resin are provided, which have a capacity in litres relative to the weight thereof in grams excluding the neck of from 0.15 to 0.5 for capacities up to 5 l and from 0.2 to 1.5 for larger capacities.

Abstract: Mono- or biaxially-stretched polyester resin foamed sheets and films wherein the polyester resin has a melt strength of more than 1 centinewton at 280° C., a melt viscosity of at least 1500 Pa.s at 280° C. for a shear ratio which tends to zero and a crystallization rate such that for a 10-minute heating at 120° C. the crystallinity can reach values as high as 30-35%.

Abstract: Use of masterbatches of polyarylene amides in polyester resins containing from 10 to 40% by weight of polyamide resin in the preparation of mixtures of aromatic polyester rensins added with the polyamide resin at a concentration of less than 15% by weight.

Abstract: Polyester resin foamed sheet, mono e biaxially stretched usable for the production of containers for beverages and foods, having a density lower than 700 kg/m3 and a crystallization rate such that, when the sheet is heated at 120° C. for 5 minutes, the crystallinity does not exceeds 15%. The aromatic polyester resin used for preparing the foamed sheet can be mixed with an aliphatic polyester resin to impart biodegradability and/or compostability to the sheet or with 1-10% by weight of a polyamide.

Abstract: Polyester resins particularly suitable for extrusion and injection blow-molding contain from 20 to 1000 ppm of a dianhydride of an aromatic tetracarboxylic acid and show values of die swell less than 45%. The resins are obtained by solid state polycondensation of resin having intrinsic viscosity less than 0.7 dl/g, added with a dianhydride of an aromatic tetracarboxylic acid in amount between 0.02 and less than 0.05% by weight.

Abstract: Articles from a polyester resin obtained by melt-shaping of the resin added with a polyfunctional compound, capable of increasing the molecular weight of the resin by addition reaction in the solid state with the end groups of the resin and by upgrading treatment of the article, so as to increase by at least 0.1 dl/g the intrinsic viscosity of the starting resin.

Abstract: Compositions comprising a polyester resin and a polyamide derived from a dicarboxylic acid with 6-22 carbon atoms and from m-xylylene diamine having high-level gas barrier properties, obtained by mixing in the melted state the polyester resin premixed with a dianhydride of a tetracarboxylic acid and the polyamide, operating under conditions such as to render the polymeric components theologically compatible each other. The compositions are suitable for preparing containers and biaxially-orientated films.

Abstract: Use of masterbatches of polyarylene amides in polyester resins containing from 10 to 40% by weight of polyamide resin in the preparation of mixtures of aromatic polyester rensins added with the polyamide resin at a concentration of less than 15% by weight.

Abstract: Aromatic polyester resins, having improved mechanical and hydrolysis resistant properties, by mixing said aromatic polyester resin with a phenoxy resin, a dianhydride of a tetracarboxylic acid and liquid crystals.

Abstract: A foamed cellular material which can be obtained from foamed aromatic polyester resins with a bulk density of 50 to 700 kg/m3 by heating in vacuum to temperatures which are higher than the Tg of the material and lower than its melting point. The foamed material, generally in the form of a sheet or panel, has high-level characteristics in terms of flexibility and dimensional thermostability depending on the degree of crystallinity after the vacuum treatment.

Abstract: Film obtained by blowing, using the bubble method from aromatic polyester resins containing a dianhydride of an aromatic tetracarboxylic acid, having thickness inferior to 10 .mu.m.

Abstract: Polyester resins containing up to 5% by weight of a polymeric liquid crystal and an upgrading agent capable of increasing the I.V. of the resin by polyaddition reaction in the solid state with the end groups of the resin. Fibers, films and biaxially oriented articles obtained from the resins.

Abstract: Articles from a polyester resin reinforced with glass fiber obtained by melt-shaping of the resin mixed with the glass fiber and a polyfunctional compound capable of increasing the intrinsic viscosity of the resin by addition reactions with the end groups of the rein using melt residence times during the shaping phase lower than 120 sec. and temperatures lower than 300.degree. C.

Abstract: Concentrates of dianhydrides of tetracarboxylic acids in polycarbonate resins containing up to about 50% by weight of dianhydride. The concentrates can be added to aromatic polyester resins in the melt in quantities equivalent to contents of dianhydride from 0.05 to 2% by weight of the resin.

Abstract: Polyamide resins characterized in melt state by high sensitivity to shear forces and high visco-elasticity, obtained by polycondensation/polyaddition in the solid state in presence of polyfunctional compounds capable of reacting with resin terminal groups and/or in presence of polyester resins employed in quantity up to about 40% by weight of the resin mixtures.

Abstract: Compositions comprising a polyester resin and a polyamide derived from a dicarboxylic acid with 6-22 carbon atoms and from m-xylylene diamine having high-level gas barrier properties, obtained by mixing in the melted state the polyester resin premixed with a dianhydride of a tetracarboxylic acid and the polyamide, operating under conditions such as to render the polymeric components theologically rheologically compatible with each other. The compositions are suitable for preparing containers and biaxially-orientated films.