Mixed aliphatic-aromatic polyesters

Abstract

A mixed aliphatic-aromatic polyester having suitable thermal properties and terminal acidity, characterized in that it has a dicarboxylic acid component comprising at least three saturated aliphatic C4-C24 dicarboxylic acids, their C1-C24 alkyl esters, their salts and mixtures thereof, always including azelaic acid and succinic acid.

Description

[Technical field]

[0001] Technical Field The present invention relates to mixed aliphatic-aromatic polyesters having suitable thermal properties and terminal acidity, characterized in that they contain at least three saturated aliphatic C4-C24 dicarboxylic acids, their C1-C24 alkyl esters, their salts and mixtures thereof, with azelaic acid and succinic acid being the dicarboxylic acid components always present. [Background technology]

[0002] Prior Art The use of biodegradable polymers to replace non-biodegradable polymers is known to be a promising and essential method to avoid intolerable environmental damage. Of course, biodegradable polymers must have good processability as well as good thermal and mechanical properties so that they can be effectively used in a variety of areas, such as the manufacture of films and / or containers. It is also known that biodegradable aliphatic-aromatic polyesters made from diacids and diols have flexible properties with low glass transition temperatures (Tg), and are particularly desirable for their amorphous properties, which provide improved chain flexibility compared to more crystalline products. See, for example, Pan et al., “Effect of Monomer Structure on Crystallisation and Glass Transition of Flexible Copolyesters,” J. Polym.Environ. (2017) 25:1051-1061.

[0003] Although the Tg behavior is known for various combinations of aliphatic-aromatic polyesters (see patent EP3240818B1), it is not easy to obtain polyesters with lower glass transition temperatures that have all the advantages pointed out above. Additionally, the presence of residual mixed cyclic oligomers in aliphatic-aromatic polyesters is known to be undesirable since it adversely affects the properties of the polyester, particularly the mechanical performance and transparency properties of the resulting film. Patent application WO2016 / 050963 discloses a combined process for the preparation of polyesters comprising an esterification or transesterification step followed by a polycondensation step, characterized in that said polycondensation step is carried out in the presence of a catalyst comprising a mixture of at least one titanium-containing compound and at least one zirconium-containing compound, in a weight ratio Ti / (Ti+Zr) between 0.01 and 0.70.

[0004] WO2016 / 050963 teaches that it is possible to obtain polyesters with reduced formation of residual cyclic oligomers. These residual cyclic oligomers are partially removed by distillation during the polycondensation step, but some of these residual cyclic oligomers remain trapped within the polyester that is formed. It has been found that by suitable selection of the process conditions described in patent application WO2016 / 050963, in particular by adding an appropriate amount of phosphorus-containing compound relative to the catalyst used, together with specific temperature and pressure conditions, it is possible to obtain mixed aliphatic-aromatic polyesters with a controlled residual amount of mixed cyclic oligomers, which successfully induces a desired reduction in the glass transition temperature.

[0005] In the present invention, the term "mixed aliphatic-aromatic polyester" refers to an aliphatic-aromatic polyester having at least three kinds of saturated aliphatic dicarboxylic acids. In the present invention, "residual mixed cyclic oligomers" means residual cyclic oligomers of less than 1000 molecular weight (MM) that remain in the polymer mass after the polycondensation process. Summary of the Invention [Means for solving the problem]

[0006] Summary of the Invention One aspect of the present invention is a method for producing a composition comprising the steps of: (a) a dicarboxylic acid component, (a1) 40 to 80 mol % of units derived from at least one aromatic dicarboxylic acid; (a2) 20 to 60 mol % of units derived from at least three saturated aliphatic C4-C24 dicarboxylic acids, including necessarily azelaic acid and succinic acid, their C1-C24 alkyl esters, their salts, and mixtures thereof; A dicarboxylic acid component comprising (b) Aliphatic diol component The mixed aliphatic-aromatic polyesters include

[0007] Another aspect of the present invention is a film obtained from the above mixed aliphatic-aromatic polyesters, preferably in admixture with other polymers, and optionally in admixture with other ingredients. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Detailed Description of the Invention In a preferred embodiment of the present invention, the mixed aliphatic-aromatic polyester comprises a residual mixed cyclic oligomer content between 1.0% and 4.0%, said residual mixed cyclic oligomer being characterized in that the ratio of cyclic oligomers comprising at least two aliphatic dicarboxylic acid units with a MM of 1000 or less to cyclic oligomers comprising only one aliphatic dicarboxylic acid unit with a MM of 1000 or less is between 0.30 and 1.40, more preferably between 0.40 and 1.20, even more preferably between 0.80 and 1.14, and further characterized in that the predominant saturated aliphatic dicarboxylic acid in component a2 is between 40 and 92 mol %, relative to the sum of all other saturated aliphatic dicarboxylic acids. The term "predominant saturated aliphatic dicarboxylic acid" in the present invention is meant to apply when the ratio of acids is not equimolar and thus refers to a saturated aliphatic dicarboxylic acid that is present in a molar percentage greater than the respective percentages of the other saturated aliphatic dicarboxylic acids.

[0009] Advantageously, the content of residual mixed cyclic oligomers is between 2% and 3.5%. The mixed aliphatic-aromatic polyesters produced by the process according to the invention comprise a diol component (component b) derived from at least one aliphatic diol selected from 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, 2-methyl-1,3-propanediol, dianhydrosorbitol, dianhydromannitol, dianhydroiditol, glycols with molecular weights of 100 to 4000, such as polyethylene glycol, polypropylene glycol, and mixtures thereof.

[0010] Preferably, the diol component comprises at least 50 mole % of one or more diols selected from 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol. More preferably, the diol component comprises or consists of 1,2-ethanediol, 1,4-butanediol, or a mixture thereof. Even more preferably, the diol component comprises or consists of 1,4-butanediol.

[0011] The dicarboxylic acid component of the polyester produced by the process according to the present invention comprises 40-80 mol %, preferably 40-75 mol %, more preferably 42-52 mol %, and even more preferably 45-49 mol % of units derived from at least one aromatic dicarboxylic acid (component a1) relative to the total dicarboxylic acid component, and 20-60 mol %, preferably 25-60 mol %, more preferably 48-58 mol %, and even more preferably 51-55 mol % of units derived from at least three saturated aliphatic dicarboxylic acids (component a2) relative to the total dicarboxylic acid component. The dicarboxylic acid component is further characterized in that the predominant saturated aliphatic dicarboxylic acid in component a2 is less than 92 mol % relative to the sum of all other saturated aliphatic dicarboxylic acids and more than 40 mol % relative to the sum of all saturated aliphatic dicarboxylic acids. The aromatic dicarboxylic acid is advantageously chosen from terephthalic acid, isophthalic acid, 2,5-furandicarboxylic acid, their esters, salts and mixtures. In a preferred embodiment, the aromatic dicarboxylic acid is - 1 to 99 mol %, preferably 5 to 95 mol %, more preferably 10 to 80 mol of terephthalic acid, its ester or its salt; 99 to 1 mol %, preferably 95 to 5 mol %, more preferably 90 to 20 mol % of 2,5-furandicarboxylic acid, its ester or salt Includes.

[0012] In a particularly preferred embodiment of the invention, the aromatic dicarboxylic acid is terephthalic acid, its esters and salts. With regard to component a2, the molar percentage of saturated aliphatic carboxylic acids of renewable origin, relative to the sum of saturated dicarboxylic acids, is preferably greater than 30%, more preferably greater than 40% and even more advantageously greater than 50%. The succinic acid in component a2 is further characterized in that it represents between 5 and 67 mol %, preferably between 10 and 50 mol %, more preferably between 20 and 35 mol %, of the sum of all other saturated aliphatic dicarboxylic acids. The azelaic acid in component a2 is preferably between 3 and 92 mol %, more preferably between 10 and 50 mol %, and even more preferably between 15 and 35 mol %, based on the sum of all other saturated aliphatic dicarboxylic acids.

[0013] The aliphatic dicarboxylic acids are advantageously chosen from saturated C4-C24, preferably C4-C13, more preferably C4-C11 aliphatic dicarboxylic acids, their C1-C24, preferably C1-C4 alkyl esters, their salts and mixtures thereof. In a preferred embodiment of the invention, the aliphatic dicarboxylic acid is selected from succinic acid, glutaric acid, 2-methylglutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid and their C1-C24 alkyl esters. In a preferred embodiment of the invention, the predominant saturated aliphatic dicarboxylic acid is at least 40 mol%, preferably 60 mol% or more, more preferably 65 mol% or more, even more preferably 85 mol% or more, based on the sum of all saturated aliphatic dicarboxylic acids. The predominant saturated aliphatic dicarboxylic acid is preferably selected from succinic acid, adipic acid, azelaic acid, sebacic acid, brassylic acid, their C1-C24, preferably C1-C4 esters, their salts and mixtures thereof, with succinic acid and azelaic acid always being present.

[0014] In a preferred embodiment of the process according to the invention, the mixed aliphatic-aromatic polyesters produced are advantageously chosen from: (A) A polyester (AAPE-A) comprising repeat units derived from a phthalic acid type aromatic dicarboxylic acid, preferably terephthalic acid, an aromatic dicarboxylic acid and an aliphatic diol, characterized by a content of aromatic units between 42 and 60 mol %, preferably between 45 and 49 mol %, relative to the total number of moles of the dicarboxylic acid component. The AAPE-A polyester is preferably selected from the following: poly(1,4-butylene azelate-co-1,4-butylene succinate-co-1,4-butylene adipate-co-1,4-butylene terephthalate), poly(1,4-butylene azelate-co-1,4-butylene succinate-co-1,4-butylene sebacate-co-1,4-butylene terephthalate), poly(1,4-butylene azelate-co-1,4-butylene succinate-co-1,4-butylene brassylate-co-1,4-butylene terephthalate), poly(1,4-butylene azelate-co-1,4-butylene succinate-co-1,4-butylene succinate-co-1,4-butylene sebacate-co-1,4-butylene terephthalate), poly(1,4-butylene azelate-co-1,4-butylene succinate-co-1,4-butylene brassylate-co-1,4-butylene terephthalate), poly(1,4-butylene azelate-co-1,4-butylene succinate-co-1,4-butylene succinate-co-1,4-butylene sebacate-co-1,4-butylene terephthalate), bacate-co-1,4-butylene terephthalate), poly(1,4-butylene azelate-co-1,4-butylene succinate-co-1,4-butylene adipate-co-1,4-butylene brassylate-co-1,4-butylene terephthalate), poly(1,4-butylene azelate-co-1,4-butylene succinate-co-1,4-butylene brassylate-co-1,4-butylene sebacate-co-1,4-butylene terephthalate), poly(1,4-butylene azelate-co-1,4-butylene succinate-co-1,4-butylene adipate-co-1,4-butylene sebacate-co-1,4-butylene brassylate-co-1,4-butylene terephthalate).

[0015] (B) A polyester (AAPE-B) comprising repeating units derived from an aromatic heterocyclic dicarboxylic acid compound, preferably 2,5-furandicarboxylic acid, an aromatic dicarboxylic acid and an aliphatic diol, characterized by a content of aromatic units between 40 mol % and 80 mol %, preferably between 40 mol % and 75 mol %, relative to the total number of moles of the dicarboxylic acid component. The AAPE-B polyester is preferably selected from the following: poly(1,4-butylene azelate-co-1,4-butylene succinate-co-1,4-butylene adipate-co-2,5-furandicarboxylate), poly(1,4-butylene azelate-co-1,4-butylene succinate-co-1,4-butylene sebacate-co-2,5-furandicarboxylate), poly(1,4-butylene azelate-co-1,4-butylene succinate-co-1,4-butylene brassylate-co-2,5-furandicarboxylate), poly(1,4-butylene azelate-co-1,4-butylene succinate-co-1,4-butylene adipate-co-1,4-butylene sebacate-co-2.5-furandicarboxylate). late), poly(1,4-butylene azelate-co-1,4-butylene succinate-co-1,4-butylene adipate-co-1,4-butylene brassylate-co-2,5-furandicarboxylate), poly(1,4-butylene azelate-co-1,4-butylene succinate-co-1,4-butylene brassylate-co-1, poly(1,4-butylene azelate-co-1,4-butylene succinate-co-1,4-butylene sebacate-co-2,5-furandicarboxylate), poly(1,4-butylene azelate-co-1,4-butylene succinate-co-1,4-butylene adipate-co-1,4-butylene sebacate-co-1,4-butylene brassylate-co-2,5-furandicarboxylate).

[0016] In a preferred embodiment of the invention, the polyesters produced by the process according to the invention are characterized by a content of residual mixed cyclic oligomers between 1.0% and 4.0%, wherein said oligomers are characterized in that the ratio of cyclic oligomers comprising at least two types of aliphatic dicarboxylic acid units with a MM less than 1000 to cyclic oligomers comprising only one type of aliphatic dicarboxylic acid unit with a MM less than 1000 is between 0.30 and 1.40, more preferably between 0.40 and 1.20, even more preferably between 0.81 and 1.14, and are further characterized in that the predominance of saturated aliphatic dicarboxylic acids in component a2 is less than 92 mol % relative to the sum of all other saturated aliphatic dicarboxylic acids and greater than 40 mol % relative to the sum of all other saturated aliphatic dicarboxylic acids.

[0017] In a preferred embodiment of the invention, the cyclic oligomers containing only one type of aliphatic dicarboxylic acid unit are (ADA-BDO)2, (AZA-BDO)2, (SEBA-BDO)2, (BRA-BDO)2, (SUC-BDO)2, (ADA-BDO)3, (AZA-BDO)3, (SEBA-BDO)3, (BRA-BDO)3, (SUC-BDO)3, (ADA-BDO)4, (AZA-BDO)4, (SUC-BDO)4. In a preferred embodiment of the present invention, the cyclic oligomer containing at least two kinds of aliphatic dicarboxylic units is (ADA-BDO-AZA-BDO), (ADA-BDO-SEBA-BDO), (ADA-BDO-BRA-BDO), (ADA-BDO-SUC-BDO), (AZA-BDO-SEBA-BDO), (AZA-BDO-BRA-BDO), (AZA-BDO-SUC-BDO), (SEBA-BDO-BRA-BDO), (SEBA-BDO-SUC-BDO), (SUC-BDO-BRA-BDO), (ADA-BDO)2-(AZA-BDO ), (ADA-BDO)-(AZA-BDO)2, (ADA-BDO)2-(SEBA-BDO), (ADA-BDO)-(SEBA-BDO)2, (ADA-BDO)2-(BRA-BDO), (ADA-BDO)-(BRA-BDO)2, (ADA-BDO)2-(SUC -BDO), (ADA-BDO)-(SUC-BDO)2, (AZA-BDO)2-(SUC-BDO), (AZA-BDO)-(SUC-BDO)2, (SEBA-BDO)2-(SUC-BDO), (SEBA-BDO)-(SUC-BDO)2, (BRA-BDO)2- (SUC-BDO), (BRA-BDO)-(SUC-BDO)2, (AZA-BDO)2-(SEBA-BDO), (AZA-BDO)-(SEBA-BDO)2, (AZA-BDO)2-(BRA-BDO), (AZA-BDO)-(BRA-BDO)2, (SEBA-B DO)2-(BRA-BDO), (SEBA-BDO)-(BRA-BDO)2, (ADA-BDO)-(PTA-BDO)-(AZA-BDO), (ADA-BDO)-(PTA-BDO)-(SEBA-BDO), (ADA-BDO)-(PTA-BDO)-(BRA-B DO), (SEBA-BDO)-(PTA-BDO)-(AZA-BDO), (BRA-BDO)-(PTA-BDO)-(AZA-BDO), (BRA-BDO)-(PTA-BDO)-(SEBA-BDO), (ADA-BDO)-(PTA-BDO)-(SUC-BDO ), (AZA-BDO)-(PTA-BDO)-(SUC-BDO), (SEBA-BDO)-(PTA-BDO)-(SUC-BDO), (BRA-BDO)-(PTA-BDO)-(SUC-BDO), (ADA-BDO)-(AZA-BDO)-(SEBA-BDO),(ADA-BDO)-(AZA-BDO)-(BRA-BDO), (ADA-BDO)-(BRA-BDO)-(SEBA-BDO), (BRA-BDO)-(AZA-BDO)-(SEBA-BDO), (ADA-BDO)-(AZA-BDO)-(SUC-B DO), (SEBA-BDO)-(AZA-BDO)-(SUC-BDO), (BRA-BDO)-(AZA-BDO)-(SUC-BDO), (SEBA-BDO)-(BRA-BDO)-(SUC-BDO), (SEBA-BDO)-(ADA-BDO)-( SUC-BDO), (ADA-BDO)2-(AZA-BDO)2, (ADA-BDO)2-(SEBA-BDO)2, (ADA-BDO)2-(BRA-BDO)2; where ADA is an ester of adipic acid with a diol component, AZA is an ester of azelaic acid with a diol component, SUC is an ester of succinic acid with a diol component, SEBA is an ester of sebacic acid with a diol component, BRA is an ester of brassylic acid with a diol component, and PTA is an ester of terephthalic acid with the diol component 1,4-butanediol.

[0018] As an example, the cyclic oligomer (SUC-BDO-AZA-BDO) consists of butylene succinate and butylene azelate units. In addition to the dicarboxylic acid and diol components, the mixed aliphatic-aromatic polyesters according to the present invention preferably contain repeat units derived from at least one hydroxy acid or corresponding lactone in an amount between 0 and 49 mol %, preferably between 0 and 30 mol %, based on the total number of moles of the dicarboxylic acid components. Examples of advantageous hydroxy acids are glycolic acid or glycolide, hydroxybutyric acid, hydroxycaproic acid, hydroxyvaleric acid, 7-hydroxyheptanoic acid, 8-hydroxyheptanoic acid, 9-hydroxynonanoic acid, lactic acid or lactide. The hydroxy acids may be incorporated into the chain as is or may be pre-reacted with a diacid or diol.

[0019] The mixed aliphatic-aromatic polyesters are prepared by the following process, which includes the steps of: 1. subjecting a mixture comprising an aliphatic diol, at least one aromatic dicarboxylic acid, and at least three saturated aliphatic dicarboxylic acids, esters, salts or derivatives thereof, to esterification and / or transesterification to produce oligomers; 2. Polycondensation of the oligomers obtained from step 1 in the presence of a catalyst, optionally a zirconium-containing catalyst or a mixture thereof, and a phosphorus-containing compound belonging to the family of organic phosphates or phosphites, at a temperature between 220° C. and 260° C. and a pressure between 0.5 mbar and 350 mbar.

[0020] Advantageously, the phosphorus-containing compound is chosen from compounds of general formula (1) or (2): [ka] (wherein R1, R2 and R3 may be selected from either H, C1-C20 alkyl or cycloalkyl, C6-C20 aryl, alkylaryl, or a polyalkylene oxide or polyalkylalkylene oxide chain.

[0021] The catalyst comprises a mixture of at least one titanium-containing compound, the titanium to phosphorus ratio being between 2 and 20, preferably between 3 and 15. In the process for preparing the mixed aliphatic-aromatic polyester according to the invention, the hydroxy acid is advantageously added in the esterification step. Longer molecules with two functional groups, including those with non-terminal functional groups, may also be present in an amount not to exceed 10 mole percent based on the total number of moles of dicarboxylic acid components. Examples are dimer acid, ricinoleic acid, and acids incorporating epoxy functional groups, as well as polyoxyethylenes having molecular weights between 200 and 10,000.

[0022] In the process for preparing the mixed aliphatic-aromatic polyesters according to the invention, these long molecules carrying two functional groups are advantageously added during the esterification step. Diamines, amino acids and amino alcohols may also be present in amounts up to 30 mole percent based on the total moles of the dicarboxylic acid component. In the process for preparing the mixed aliphatic-aromatic polyesters according to the invention, such diamines, amino acids and amino alcohols are advantageously added during the esterification step. During the esterification step of the process for making the mixed aliphatic-aromatic polyesters according to the present invention, one or more molecules characterized by having three or more reactive functional groups may be added in an amount between 0.02 and 3 mole % based on the total number of moles of dicarboxylic acid component (and any hydroxy acid) to obtain branched products.

[0023] Examples of these molecules are glycerol, pentaerythritol, trimethylolpropane, citric acid, dipentaerythritol, monoanhydrosorbitol, monoanhydromannitol, acid triglycerides or polyglycerols. The molecular weight Mn of the mixed aromatic-aliphatic polyester according to the present invention is preferably 20,000 or more, more preferably 30,000 or more, and further preferably 50,000 or more. The molecular weight polydispersity index Mw / Mn is preferably between 1.5 and 10, more preferably between 1.6 and 5, even more preferably between 1.8 and 2.5. The molecular weights Mn and Mw may be measured by gel permeation chromatography (GPC). Measurements may be performed in a chromatographic system maintained at 40°C using a set of two columns in series (mixed porosity of 5 μm and 3 μm particle sizes), a refractive index detector, chloroform as eluent (flow rate 0.5 ml / min) and polystyrene as the reference standard.

[0024] The thermal properties of the mixed aromatic-aliphatic polyesters according to the present invention were measured by differential scanning calorimetry (DSC) using a PerkinElmer Pyris Diamond calorimeter under the conditions given below: - 60 sec, isothermal at -80°C - First scan from -80°C to 200°C at 20°C / min - 60 seconds, 200°C isothermal - 2nd scan from 200°C to -80°C at 10°C / min - 60 sec, isothermal at -80°C - 3rd scan from -80°C to 200°C at 20°C / min

[0025] At the glass transition temperature, a change in specific heat (ΔCp) occurs, which can be detected as a jump and change in slope of the DSC curve. The glass transition temperature (Tg) was calculated from the second scan by drawing two lines that imaginarily extend the baseline before and after the transition and a tangent to the maximum slope of the curve, using PerkinElmer's PyrisTM software, which is specially designed for processing DSC diagrams. The glass transition temperature in this invention is defined as the point where half of the heat capacity increase is reached (midpoint temperature). In the process of patent WO2016 / 050963, the use of a catalyst comprising a mixture of at least one titanium-containing compound and at least one zirconium-containing compound, in which the weight ratio Ti / (Ti+Zr) in the polycondensation step is greater than 0.01 and less than 0.70, preferably greater than 0.02 and less than 0.60, allows the amount of residual cyclic oligomers obtained after extraction of the polycondensation distillate to be reduced. In particular, the content of these residual cyclic oligomers is determined gravimetrically after separation from the polycondensation distillate.

[0026] Instead, in the present invention, it is possible to control the amount of mixed cyclic oligomers remaining in the formed polyester by using a phosphorus-containing compound in a mixture with at least one titanium-containing compound having a titanium to phosphorus ratio between 2 and 20, preferably between 3 and 15, where the ratio of cyclic oligomers containing at least two dicarboxylic acid aliphatic units having a MM of less than 1000 to cyclic oligomers containing only one dicarboxylic acid aliphatic unit having a MM of less than 1000 is between 0.30 and 1.40. The residual mixed cyclic oligomers extracted are weighed. An accurately weighed polymer sample of about 30 g was extracted with 150 ml acetonitrile at 40° C. for 96 hours. The liquid phase was collected by filtration and the granules on the filter were washed with 25 ml acetonitrile. The two liquid aliquots were combined in a 250 ml volumetric flask and the solvent was evaporated to constant weight on a rotary evaporator at 45° C. The composition of the residual mixed cyclic oligomers was analyzed by dissolving the oligomers in 1 ml THF and diluting with acetonitrile to a concentration of about 1000 ppm. 100 μl of the acetonitrile / THF solution was diluted with 800 μl methanol and 100 μl of 0.1% N aqueous solution of ammonium acetate.

[0027] Analyses were performed by HPLC-MS using a Thermo Accela 1250 HPLC system coupled to a Thermo LCQ Fleet mass spectrometer in ESI+ mode. The species were separated using a Phenomenex Luna Omega C18 PS 100 x 2.1 mm 1.6 um column, eluting according to the profile in Table 1.

[0028] [Table 1]

[0029] Oligomers were recognized based on the molecular weight (MM) of the protonated and ammonia adducts. The percentage of residual mixed cyclic oligomers was determined by processing the chromatograms in base peak mode and integrating the species recognized as cyclic oligomers based on their molecular weight. The ratio of the total area of ​​the peaks assigned to oligomers containing at least two aliphatic acids with MM less than 1000 to the total area of ​​the peaks assigned to cyclic oligomers containing only one aliphatic dicarboxylic acid unit with MM less than 1000 represents the percentage of mixed cyclic oligomers. The terminal acid group content of the mixed aromatic-aliphatic polyester is preferably 100 meq / kg or less, preferably 60 meq / kg or less, more preferably 40 meq / kg or less.

[0030] The content of terminal acid groups can be measured as follows: 1.5-3 g of polyester is placed in a 100 ml flask with 60 ml of chloroform. After the polyester is completely dissolved, 25 ml of 2-propanol is added, followed by 1 ml of deionized water immediately prior to analysis. The resulting solution is titrated with a prestandardized solution of KOH in ethanol. The titration end point is determined using a suitable indicator (eg a glass electrode for acid-base titrations in non-aqueous media). The content of terminal acid groups is calculated from the consumption of KOH solution in ethanol according to the following formula:

number

[0031] For use in typical applications of plastics (e.g., bubble film formation, injection molding, foamed products, etc.), the melt mass flow rate (MFR) of the mixed aliphatic-aromatic polyester according to the invention is preferably between 500 and 1 g / 10 min, more preferably between 100 and 2 g / 10 min, and even more preferably between 80 and 3 g / 10 min. MFRs between 25 and 3.5 g / 10 min (measured at 190 ° C / 2.16 kg according to ISO 1133-1) can be advantageously used. Preferably, the mixed aliphatic-aromatic polyesters according to the present invention have an intrinsic viscosity (measured with an Ubbelohde viscometer for a solution in CHCl3 at a concentration of 0.2 g / dl at 25° C.) greater than 0.4 dl / g, preferably between 0.4 and 2 dl / g, more preferably between 0.7 and 1.5 dl / g. Preferably, the mixed aliphatic-aromatic polyesters according to the present invention are biodegradable. In the sense of the present invention, biodegradable polymer is understood to mean a biodegradable polymer which has a relative biodegradability to microcrystalline cellulose of 90% or more after 180 days according to ISO 14855-1 (2013).

[0032] In a preferred embodiment of the present invention, said mixed aliphatic-aromatic polyesters comprising between 45 and 49 mol % of units derived from at least one aromatic dicarboxylic acid (component a1), based on the total dicarboxylic acid component, and between 20 and 60 mol % of units derived from succinic acid, based on the total dicarboxylic acid component, are biodegradable in industrial composting according to standard EN13432. Preferably, the mixed aliphatic-aromatic polyesters according to the invention can be used in admixture with one or more polymers of synthetic or natural origin, whether biodegradable or not, and can also be obtained by reactive extrusion processes. In particular, the mixed aliphatic-aromatic polyesters according to the invention, when mixed with other polymers, preferably with an appropriate combination of other components, are particularly suitable for the manufacture of films, which advantageously exhibit excellent mechanical properties.

[0033] In a particularly preferred embodiment of the invention, the film made from the blend of mixed aromatic-aliphatic polyesters comprises: i) 30 to 95% by weight, based on the sum of components i.-v., of at least one mixed aliphatic-aromatic polyester; ii) 0.1 to 50% by weight, based on the sum of components i.-v., of at least one polymer of natural origin; iii) 0 to 40% by weight, based on the sum of components i.-v., of at least one polyhydroxyalkanoate; iv) 0 to 15% by weight, based on the sum of components i.-v., of at least one inorganic filler; v) 0 to 5% by weight, based on the sum of components i.-v., of at least one crosslinker and / or chain extender comprising at least one di- and / or polyfunctional compound, including isocyanates, peroxides, carbodiimides, isocyanurates, oxazolines, epoxides, anhydrides, divinyl ethers and mixtures thereof.

[0034] The naturally occurring polymer (component ii) is selected from the group comprising starch, cellulose, chitin, chitosan, alginate, proteins such as gluten, zein, casein, collagen, gelatin, natural rubber, rosin acid and its derivatives, lignin itself or purified, hydrolyzed, basified etc. lignin or its derivatives. The starches and celluloses may be modified, such as esters of starch or cellulose with a degree of substitution of 0.2 to 2.5, hydroxypropylated starches, starches modified with fatty chains, and cellophane. Component (ii) is preferably starch. Starch may be used in both unstructured and gelled forms or as a filler. By destructured starch is meant starches as described in patents EP 0 118 240 and EP 0 327 505, in particular starches which have been modified in such a way that they do not show the so-called "Maltese cross" under polarized optical microscopy and do not show the so-called "ghosts" under phase-contrast optical microscopy. The starch may be in the continuous or dispersed phase or may be in a co-continuous morphology.

[0035] In the case of dispersed starches, the particle size of the starch is measured cross-sectionally relative to the machine direction during extrusion, or in any case cross-sectionally relative to the direction of film production. Starch particle size is measured from the two-dimensional profile of the cross section. The average starch particle size is calculated as the arithmetic mean of the particle sizes. If the particle has a circular cross section, the particle size corresponds to the diameter of that circle. For particles having an elliptical cross section or other cross section similar to an ellipse, the particle size (d) is calculated by the following formula:

number

[0036] The starch particles are characterized by an arithmetic mean diameter, measured as above, of less than 1 micron, more preferably less than 0.5 microns. Component iii of the above film optionally contains at least one polyhydroxyalkanoate, preferably in an amount of 0 to 40%, more preferably 2 to 37%, and even more preferably 10 to 25%, based on the sum of components i to v. The polyhydroxyalkanoates are most preferably selected from the group comprising polyesters of lactic acid, poly-ε-caprolactone, polyhydroxybutyrate, polyhydroxybutyrate-valerate, polyhydroxybutyrate-propanoate, polyhydroxybutyrate-hexanoate, polyhydroxybutyrate-decanoate, polyhydroxybutyrate-dodecanoate, polyhydroxybutyrate-hexadecanoate, polyhydroxybutyrate-octadecanoate, poly 3-hydroxybutyrate-4-hydroxybutyrate. Preferably, the polyhydroxyalkanoates comprise at least 80% by weight of one or more polyesters of lactic acid.

[0037] In one preferred embodiment, the lactic acid polyester is selected from the group consisting of poly-L-lactic acid, poly-D-lactic acid, poly-DL-lactic acid stereocomplex, copolymers containing 50 mol% or more of the above lactic acid polyester, and mixtures thereof. Particularly preferred is a lactic acid polyester containing at least 95% by weight of repeating units derived from L-lactic acid or D-lactic acid or a mixture thereof, and having a molecular weight Mw of 50,000 or more and a shear viscosity of 50 to 500 Pa.s, preferably 100 to 300 Pa.s (measured according to ASTM standard D3835 at T=190°C, shear rate=1000s-1, D=1mm, L / D=10). In one particularly preferred embodiment, the lactic acid polyester contains at least 95% by weight of units derived from L-lactic acid, <5% of repeat units derived from D-lactic acid, and has a melting point between 135-180° C., a glass transition temperature (Tg) between 55-65° C., and a MFR (measured according to ISO 1133-1 at 190° C. and 2.16 kg) in the range of 1-50 g / 10 min. Commercially available examples of lactic acid polyesters with such properties include Ingeo TM Biopolymer products are 4043D, 3250D and 6202D. The inorganic filler of the film (component iv) is present in an amount of 0-15% by weight, preferably 0.1-8% by weight, more preferably 3-5% by weight, based on the sum of components i to v. The inorganic filler is preferably selected from kaolin, baryte, clay, talc, calcium and magnesium, calcium, iron and lead carbonates, aluminium hydroxide, diatomaceous earth, aluminium sulphate, barium sulphate, silica, mica, titanium dioxide and wollastonite.

[0038] In one preferred embodiment of the present invention, the inorganic filler comprises talc, mica, calcium carbonate or mixtures thereof present in the form of particles having an average arithmetic diameter measured relative to the major axis of the particle (measured according to ASTM 13320) of 10 microns or less, more preferably 2 microns or less. The crosslinker and / or chain extender (component v) of the film described above is present in an amount of 0 to 5% by weight, preferably 0 to 0.5% by weight, based on the sum of components i to v. The crosslinking agents and / or chain extenders are selected from di- and / or polyfunctional compounds having groups selected from isocyanates, peroxides, carbodiimides, isocyanurates, oxazolines, epoxies, anhydrides, divinyl ethers, and combinations thereof. Particularly preferred are mixtures of di- and / or polyfunctional compounds containing isocyanate groups and di- and / or polyfunctional compounds containing epoxide groups, and even more preferred are mixtures which contain at least 75% by weight of di- and / or polyfunctional compounds containing isocyanate groups.

[0039] The bifunctional and polyfunctional compounds containing isocyanate groups are preferably p-phenylene diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4-diphenylmethane diisocyanate, 1,3-phenylene-4-chlorodiisocyanate, 1,5-naphthalene diisocyanate, 4,4-diphenylene diisocyanate, 3,3'-dimethyl-4,4-diphenylmethane diisocyanate, 3-methyl-4,4'-diphenylmethane diisocyanate, diphenyl ester diisocyanate, 2,4 The isocyanate-containing compound is selected from the group consisting of 1,2-cyclohexane diisocyanate, 2,3-cyclohexane diisocyanate, 1-methyl 2,4-cyclohexyl diisocyanate, 1-methyl-2,6-cyclohexyl diisocyanate, bis(isocyanatocyclohexyl)methane, 2,4,6-toluene triisocyanate, 2,4,4-diphenylether triisocyanate, polymethylene-polyphenyl-polyisocyanate, methylene diphenyl diisocyanate, triphenylmethane triisocyanate, 3,3'-dithiolylene-4,4-diisocyanate, 4,4'-methylene bis(2-methylphenylisocyanate), hexamethylene 1,3-cyclohexylene diisocyanate, 1,2-cyclohexylene diisocyanate and mixtures thereof. In one preferred embodiment, the compound containing isocyanate groups is 4,4-diphenylmethane-diisocyanate.

[0040] As regards the di- and polyfunctional compounds carrying peroxide groups, these are preferably selected from benzoyl peroxide, lauroyl peroxide, isononanoyl peroxide, di(t-butylperoxyisopropyl)benzene, t-butyl peroxide, dicumyl peroxide, α,α'-di(t-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hex-3-yne, di(4-t-butylcyclohexyl)peroxydicarbonate, dicetyl peroxydicarbonate, dimyristyl peroxydicarbonate, 3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane, di(2-ethylhexyl)peroxydicarbonate and mixtures thereof.

[0041] Di- and polyfunctional compounds having carbodiimide groups, which are preferably used in the compositions according to the invention, are poly(cyclooctylenecarbodiimide), poly(1,4-dimethylenecyclohexylenecarbodiimide), poly(cyclohexylenecarbodiimide), poly(ethylenecarbodiimide), poly(butylenecarbodiimide), poly(isobutylenecarbodiimide), poly(nonylenecarbodiimide), poly(dodecylenecarbodiimide), poly(neopentylenecarbodiimide), poly(L / 1,4-dimethylenephenylenecarbodiimide), poly(2,2',6,6'-tetraisopropyldiphenylenecarbodiimide) (Stabaxol® D), poly(2,4,6-triisopropyl-1,3-phenylenecarbodiimide) (Stabaxol® P-100), poly(2,6-diisopropyl-1,3-phenylenecarbodiimide) (Stabaxol® P-200), poly(2,6-di ... poly(p-phenylenecarbodiimide), poly(m-phenylenecarbodiimide), poly(3,3'-dimethyl-4,4'-diphenylmethanecarbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylenecarbodiimide), poly(3,3'-dimethyl-4,4'-diphenylmethanecarbodiimide), poly( naphthylenecarbodiimide), poly(isophoronecarbodiimide), poly(cumenecarbodiimide), p-phenylenebis(ethylcarbodiimide), 1,6-hexamethylenebis(ethylcarbodiimide), 1,8-octamethylenebis(ethylcarbodiimide), 1,10-decamethylenebis(ethylcarbodiimide), 1,12-decamethylenebis(ethylcarbodiimide) and mixtures thereof.

[0042] Examples of di- and polyfunctional compounds carrying epoxide groups that may be advantageously used in the compositions according to the invention are polyepoxides from epoxidized oils and / or from styrene-glycidyl ether-methyl methacrylate or glycidyl ether-methyl methacrylate, all within the molecular weight range of 1000 to 10000 and with 1 to 30, preferably 5 to 25, epoxides per molecule, selected from the group comprising: diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polyglycerol polyglycidyl ether, 2-epoxybutane, polyglycerol polyglycidyl ether, isoprene diepoxide and cycloaliphatic diepoxide, 1,4-cyclohexanedimethanol diglycidyl ether, glycidyl 2-methylphenyl ether, glycerol propoxylato triglycidyl ether, glycerol propoxylato triglycidyl ether, tetraglycidyl ether of meta-xylylene diamine and diglycidyl ether of bisphenol A, and mixtures thereof. In conjunction with bifunctional and polyfunctional compounds having isocyanate, peroxide, carbodiimide, isocyanurate, oxazoline, epoxide, anhydride and divinyl ether groups (such as those mentioned above), a catalyst may also be used to enhance the reactivity of the reactive groups. In the case of polyepoxides, fatty acid salts may be preferably used, and more preferably calcium stearate and zinc stearate may be used.

[0043] In one particularly preferred embodiment of the invention, the crosslinker and / or chain extender comprises a compound having an isocyanate group, preferably 4,4-diphenylmethane-diisocyanate, and / or a compound having a carbodiimide group, and / or a compound having an epoxide group, preferably of the styrene-glycidyl ether methyl methacrylate type. In addition to film production, the mixed aliphatic-aromatic polyesters according to the invention are highly suitable for use alone or in mixtures with other polymers in many practical applications for the production of products such as, for example, fibers, nonwovens, foils, prints, thermoformed articles, blow molded articles, expansion molded articles, laminated articles (including those produced by extrusion coating techniques), and the like.

[0044] Examples of products comprising the mixed aliphatic-aromatic polyesters according to the invention are: -films (uniaxially and biaxially oriented films) and multilayer films with other polymeric materials; - Films for use as mulch films in agricultural fields; -Stretch films, including food film, agricultural packaging and waste packaging; -Bags and liners for organic matter collection, such as food waste and grass clippings; -Single and multi-layer thermoformed food packaging, such as containers for milk, yogurt, meat, beverages, etc.; - Coatings obtained using extrusion coating technology; - multi-layer laminates having layers of cardboard, plastic, aluminum and metallized film; - Foam or expandable beads for the production of special sintered forms; -Foamed and semi-foamed products, including foam blocks formed from pre-expanded particles; - Expanded foams, thermoformed foam sheets and containers made from them for food packaging; -General fruit and vegetable containers; - compositions containing gelatinized, destructured and / or complex starches, native starches, flours, other fillers of natural, vegetable or inorganic origin as fillers; - Fibres, microfibers, bicomponent fibres with a core made of a hard polymer such as PLA, PET, PTT and an outer shell of the material according to the invention, double-blend bicomponent fibres, fibres with various cross sections from round to multilobal fibres, flocked, woven, nonwoven or spunbonded or thermobonded fabrics for the health, hygiene, agriculture and clothing sectors. They can be used as a substitute for plasticized PVC.

[0045] The method for producing a mixed aliphatic-aromatic polyester according to the present invention comprises an esterification or transesterification step and a polycondensation step, characterized in that said polycondensation step is carried out in the presence of a catalyst comprising at least one compound containing titanium and optionally at least one compound containing zirconium. When the compound containing zirconium is present, the weight ratio Ti / (Ti+Zr) is 0.01 to 0.7, preferably 0.02 to 0.60. Furthermore, the catalyst is used in a mixture with phosphorus compounds belonging to the family of organic phosphates or phosphites.

[0046] Advantageously, the phosphorus-containing compound is chosen from compounds of general formula (1) or (2): [ka] (wherein R1, R2 and R3 may be selected from either H, C1-C20 alkyl or cycloalkyl, C6-C20 aryl, alkylaryl, or a polyalkylene oxide or polyalkylalkylene oxide chain.)

[0047] In a particularly preferred embodiment, the phosphorus-containing compound is trioctyl phosphate. In a preferred embodiment of the process, the catalyst comprises a mixture of at least one compound containing titanium, the weight ratio of titanium to phosphorus being between 2-20, preferably between 3-15. In the esterification / transesterification step, a molar ratio between the aliphatic diol and the dicarboxylic acid, esters and salts thereof is preferably provided between 1 and 2.5, preferably between 1.05 and 1.9. The dicarboxylic acids, their esters or salts, the aliphatic diols and other comonomers which make up the polyester may be fed separately to the process and mixed in the reactor or may be premixed, preferably at T<70° C., before being fed to the reactor. It is also possible to premix some of the components and then modify the composition, for example during the esterification / transesterification reaction.

[0048] In the case of polyesters in which the dicarboxylic acid component contains repeat units derived from multiple dicarboxylic acids, whether aliphatic or aromatic, it is also possible to premix some of these with the aliphatic diol, preferably at T<70° C., and add the remaining dicarboxylic acids, diols and other comonomers to the esterification / transesterification reactor. The esterification / transesterification step of this process is advantageously carried out at a temperature between 200 and 250° C. and a pressure between 0.7 and 1.5 bar, preferably in the presence of an esterification / transesterification catalyst. The esterification / transesterification catalyst, which can advantageously also be used as a component of the catalyst for the polycondensation step, may be fed directly to the esterification / transesterification reactor or may first be dissolved in one or more aliquots of the dicarboxylic acid, ester or salt thereof, and / or aliphatic diol to facilitate distribution and make it more uniform in the reaction mixture.

[0049] The esterification / transesterification catalyst is selected from organometallic tin compounds, such as stannic acid derivatives, titanium compounds, such as titanates, such as tetrabutyl orthotitanate or tetra(isopropyl) orthotitanate, zirconium compounds, such as zirconates, such as tetrabutyl ortho-zirconate or tetra(isopropyl) ortho-zirconate, antimony compounds, aluminum, such as Al-triisopropyl, and zinc compounds, and mixtures thereof. For organometallic esterification / transesterification catalysts of the type mentioned above, they are preferably present in a metal concentration of 12 to 120 ppm, based on the amount of polyester theoretically obtainable by converting all the dicarboxylic acid fed to the reactor in the esterification / transesterification step of the process. The catalyst for the esterification / transesterification step is a titanate, more preferably diisopropyltriethanolaminotitanate, preferably used at a metal concentration of 12 to 120 ppm relative to the amount of polyester theoretically obtainable by converting all of the dicarboxylic acid fed to the reactor. Preferably, the reaction time of the esterification / transesterification step in the process according to the invention is between 4 and 8 hours. At the end of the esterification / transesterification process, an oligomeric product is obtained with Mn<5000, intrinsic viscosity of 0.05-0.15 dl / g, and acid value<150 meq / kg. The catalyst may be fed to the polycondensation step along with the oligomeric products at the end of the esterification / transesterification step.

[0050] The polycondensation step is carried out in the presence of a catalyst comprising titanium, optionally zirconium or a mixture thereof, and a phosphorus-containing compound belonging to the family of organic phosphates or phosphites, the total amount of titanium being between 80 and 500 ppm relative to the amount of polyester theoretically obtainable by catalytic conversion of all the dicarboxylic acids fed to the reactor. The titanium to phosphorus ratio is between 2 and 20, preferably between 3 and 15. If present, the total amount of zirconium must be such that the Ti / (Ti+Zr) ratio is kept in the range of 0.01 to 0.70. In a preferred embodiment of the process for preparing mixed aliphatic-aromatic polyesters according to the invention, the titanium-containing polycondensation catalyst is a titanate advantageously chosen from compounds having the general formula Ti(OR)4, where R is a ligand group containing one or more atoms of carbon, oxygen, phosphorus and / or hydrogen. Different ligand groups R may be present on the same titanium atom, but preferably they are the same for ease of titanate preparation. Furthermore, two or more ligands R may be derived from a single compound and may be chemically bonded together in addition to being bound by titanium (so-called multidentate ligands such as triethanolamine, citric acid, glycolic acid, malic acid, succinic acid, ethanediamine, etc.). R is advantageously selected from the group comprising H, triethanolamine, citric acid, glycolic acid, malic acid, succinic acid, 3-oxobutanoic acid, ethanediamine and linear or branched C1-C12 alkyl residues, such as ethyl, propyl, n-butyl, pentyl, isopropyl, isobutyl, isopentyl, hexyl, ethylhexyl. In a preferred embodiment, R is selected from C1-C12 alkyl residues, preferably C1-C8, more preferably n-butyl.

[0051] The preparation of titanates is well known in the literature and is typically prepared by reacting titanium tetrachloride with a precursor alcohol of formula ROH in the presence of a base such as ammonia, or by transesterification of other titanates. Commercially available examples of titanates that can be used in the preferred embodiment of the process for producing the aromatic-aliphatic mixed polyester according to the present invention include Tyzor® TPT (tetraisopropyl titanate), Tyzor® TnBT (tetra n-butyl titanate) and Tyzor® TE (diisopropyl triethanolamino titanate).

[0052] When a zirconium-containing polycondensation catalyst is used in combination with a titanium-containing polycondensation catalyst, this is a zirconate advantageously chosen from compounds of general formula Zr(OR)4, where R is a ligand group consisting of one or more atoms of carbon, oxygen, phosphorus and / or hydrogen. As in the case of the titanates, different (but preferably the same) ligand groups R may be present on the same zirconate atom. In addition, two or more ligands R may be derived from a single compound or may be chemically bound together in addition to being bound to zirconium (so-called polydentate ligands such as triethanolamine, citric acid, glycolic acid, malic acid, succinic acid, ethanediamine, etc.). R is advantageously selected from the group comprising H, triethanolamine, citric acid, glycolic acid, malic acid, succinic acid, 3-oxobutanoic acid, ethanediamine, and linear or branched C1-C12 alkyl residues, such as ethyl, propyl, n-butyl, pentyl, isopropyl, isobutyl, isopentyl, hexyl or ethylhexyl. In a preferred embodiment, R is selected from C1-C12, preferably C1-C8, alkyl residues, more preferably n-butyl. Methods for the preparation of zirconates are known in the literature and are similar to those described above for the titanates.

[0053] Commercially available examples of zirconates that can be used in the preferred embodiment of the method for producing an aromatic-aliphatic mixed polyester according to the present invention include Tyzor (registered trademark) NBZ (tetra n-butyl zirconate), Tyzor NPZ (tetra n-propyl zirconate), IG-NBZ (tetra n-butyl zirconate), Tytan TNBZ (tetra n-butyl zirconate), Tytan TNPZ (tetra n-propyl zirconate), and the like. The polycondensation catalyst and phosphorus-containing compound are fed to the polycondensation step by feeding the various components separately to the reactor. It is also possible to premix some of the components and then adjust the composition of the catalyst, for example, when the catalyst is contacted with the oligomer product. When using a catalyst comprising a titanium and / or zirconium compound in the esterification / transesterification step of the process for producing the mixed aromatic-aliphatic polyesters according to the invention, in a preferred embodiment of the process according to the invention, this catalyst is not separated from the oligomer product but is fed together therewith to the polycondensation step, advantageously used as or as a component of the polycondensation catalyst, the molar ratio of titanium to zirconium being adjustable by adding appropriate amounts of titanium and zirconium compounds to said polycondensation step.

[0054] The catalyst for the polycondensation step may be the same as the catalyst for the esterification / transesterification step. The polycondensation step is advantageously carried out by feeding the oligomer product to a polycondensation reactor and reacting it in the presence of a catalyst at a temperature of 220-260° C. and a pressure of 0.5 mbar-350 mbar. Preferably, the reaction time of the polycondensation step is 4 to 8 hours. Depending on the specific molecular weight characteristics of the polyester and the desired viscosity, the process according to the invention can provide, after the polycondensation step, one or more steps of chain extension, reactive processing or reactive extrusion with other polymers by using peroxides, divinyl ethers, bisoxazolines, polyepoxides, di- and polyisocyanates, carbodiimides or dianhydrides. The invention will be described with the aid of several embodiments, which should be understood as illustrative and not limiting the scope of protection of the present patent application. EXAMPLES

[0055] Working Example Example 1 (Comparative) - Preparation of poly(1,4-butylene adipate-co-1,4-butylene sebacate-co-1,4-butylene succinate-co-1,4-butylene terephthalate) [PBTAdSebSuc 50 / 28 / 22] using 50 mol % adipic acid, 28 mol % sebacic acid, and 22 mol % succinic acid based on the total aliphatic carboxylic acids.

[0056] Esterification process A steel reactor of geometric volume 60 liters, equipped with a mechanical stirring system, nitrogen inlet, distillation column, high boiling distillate knockdown system, and connection to a high vacuum system, was charged with the following, in a diol to dicarboxylic acid molar ratio (MGR) of 1.50: 8004 g terephthalic acid, 3969 g adipic acid, 3075 g sebacic acid, 1411 g succinic acid, 113850 g 1,4-butanediol, 4.72 g glycerol, and 5.50 g of an 80 wt % ethanolic solution of diisopropyl triethanolamino titanate (Tyzor TE, equivalent to 21 ppm metals relative to the amount of PBTAdSebSuc theoretically obtained by converting all the adipic acid, all the sebacic acid, all the succinic acid and terephthalic acid fed to the reactor). The temperature of the mass was gradually increased to 230° C. over a period of 120 minutes.

[0057] Polycondensation Phase When at least 95% of the theoretical water had been distilled, 24.20 g of tetra n-butyl titanate (corresponding to 154 ppm of metal relative to the amount of PBTAdSebSuc theoretically obtained by converting all adipic acid, all sebacic acid, all succinic acid, and all terephthalic acid fed to the reactor) and 5.39 g of trioctyl phosphate (corresponding to 17.5 ppm of phosphorus relative to the amount of PBTAdSebSuc theoretically obtained by converting all adipic acid, all sebacic acid, all succinic acid, and all terephthalic acid fed to the reactor, thus corresponding to a Ti / P weight ratio of 10) were obtained. The reactor temperature was then increased to 242° C. and gradually reduced pressure to 1.2 mbar or less over 60 minutes. The reaction was allowed to proceed for approximately 4.30 hours, which was the time required to obtain PBTAdSebSuc with a MFR of 4.3 g / 10 min (190° C., 2.16 kg), after which the material was discharged in the form of strings into a water bath and granulated.

[0058] Example 2 - Preparation of poly(1,4-butylene adipate-co-1,4-butylene azelaic acid-co-1,4-butylene succinate-co-1,4-butylene terephthalate) [PBTAdAzSuc 50 / 28 / 22] using 50 mol % adipic acid, 28 mol % azelaic acid, and 22 mol % succinic acid based on the total aliphatic carboxylic acids. The operating conditions of Example 1 were repeated, except that 8082 g of terephthalic acid, 4008 g of adipic acid, 2890 g of azelaic acid, 1425 g of succinic acid, 13985 g of 1,4-butanediol, 4.77 g of glycerol, and 5.50 g of an 80 wt. % solution of diisopropyl triethanolamino titanate in ethanol (Tyzor TE, equivalent to 21 ppm metals relative to the amount of PBTAdAzSuc theoretically obtained by converting all the adipic acid, all the sebacic acid, all the succinic acid, and all the terephthalic acid fed to the reactor) were charged. PBTAdAzSuc was obtained with a MFR of 4.5 g / 10 min (190° C., 2.16 kg).

[0059] Example 3 - Preparation of poly(1,4-butylene adipate-co-1,4-butylene azelaic acid-co-1,4-butylene succinate-co-1,4-butylene terephthalate) [PBTAdSebAzSuc 50 / 14 / 14 / 22] using 50 mol% adipic acid, 14 mol% sebacic acid, 14 mol% azelaic acid, and 22 mol% succinic acid based on the total aliphatic carboxylic acids. The operating conditions of Example 1 were repeated, except that 8043 g of terephthalic acid, 3989 g of adipic acid, 1545 g of sebacic acid, 1438 g of azelaic acid, 1418 g of succinic acid, 13917 g of 1,4-butanediol, 4.74 g of glycerol and 5.50 g of an 80 wt % solution of diisopropyl triethanolamino titanate in ethanol (Tyzor TE, equivalent to 21 ppm metals relative to the amount of PBTAdSebAzSuc theoretically obtained by converting all the adipic acid, all the sebacic acid, all the azelaic acid, all the succinic acid and all the terephthalic acid fed to the reactor) were charged. This resulted in PBTAdSebAzSuc with a MFR of 4.6 g / 10 min (190° C., 2.16 kg).

[0060] Example 4 (Comparative) - Preparation of poly(1,4-butylene sebacate-co-1,4-butylene succinate-co-1,4-butylene terephthalate) [PBTSebSuc 50 / 50] using 50 mole % sebacic acid and 50 mole % succinic acid based on the total aliphatic carboxylic acids combined. The operating conditions of Example 1 were repeated, with the difference that in the esterification step, 7916 g of terephthalic acid, 5432 g of sebacic acid, 3173 g of succinic acid, 13698 g of 1,4-butanediol, 4.67 g of glycerol and 5.50 g of an 80 wt.% solution of diisopropyl triethanolamino titanate in ethanol (Tyzor TE, equivalent to 21 ppm metals relative to the amount of PBTSebSuc theoretically obtained by converting all the sebacic acid, all the succinic acid and all the terephthalic acid fed to the reactor) were charged. In the polycondensation step, no trioctyl phosphate was added. PBTSebSuc was obtained with an MFR of 5.5 g / 10 min (190° C., 2.16 kg).

[0061] Example 5 (Comparative) - Preparation of poly(1,4-butylene azelaic acid-co-1,4-butylene succinate-co-1,4-butylene terephthalate) [PBTAzSuc 50 / 50] using 50 mole % azelaic acid and 50 mole % succinic acid relative to the total aliphatic carboxylic acids combined. The operating conditions of Example 1 were repeated, with the difference that in the esterification step, 8054 g of terephthalic acid, 5143 g of azelaic acid, 3228 g of succinic acid, 13936 g of 1,4-butanediol, 4.75 g of glycerol and 5.50 g of an 80 wt.% ethanolic solution of diisopropyl triethanolamino titanate (Tyzor TE, corresponding to 21 ppm metals relative to the amount of PBTAzSuc theoretically obtained by converting all the azelaic acid, all the succinic acid and all the terephthalic acid fed to the reactor) were charged. In the polycondensation step, no trioctyl phosphate was added. PBTAzSuc was obtained with an MFR of 6.0 g / 10 min (190° C., 2.16 kg).

[0062] Example 6 - Preparation of poly(1,4-butylene adipate-co-1,4-butylene azelaic acid-co-1,4-butylene succinate-co-1,4-butylene terephthalate) [PBTAdAzSuc 50 / 18.5 / 31.5] using 50 mol % adipic acid, 18.5 mol % azelaic acid, and 31.5 mol % succinic acid based on the total aliphatic carboxylic acids.

[0063] Esterification process A steel reactor of geometric volume 60 liters, equipped with a mechanical stirring system, a nitrogen inlet, a distillation column, a high boiling distillate knockdown system, and a connection to a high vacuum system, was charged with the following, in a diol to dicarboxylic acid molar ratio (MGR) of 1.50: 8180 g terephthalic acid, 4133 g adipic acid, 2065 g azelaic acid, 1933 g succinic acid, 14153 g 1,4-butanediol, 4.82 g glycerol, and 5.50 g of an 80 wt % ethanolic solution of diisopropyl triethanolamino titanate (Tyzor TE, equivalent to 21 ppm metals relative to the amount of PBTAdSebSuc theoretically obtained by converting all the adipic acid, all the sebacic acid, all the succinic acid, and terephthalic acid fed to the reactor). The temperature of the mass was gradually increased to 230° C. over a period of 120 minutes.

[0064] Polycondensation Phase When at least 95% of the theoretical water has been distilled, 16.5 g of tetra n-butyl titanate (corresponding to 105 ppm of metal relative to the amount of PBTAdAzSuc theoretically obtained by converting all adipic acid, all azelaic acid, all succinic acid and all terephthalic acid fed to the reactor) and 6.47 g of trioctyl phosphate (corresponding to 21 ppm of phosphorus relative to the amount of PBTAdAzSuc theoretically obtained by converting all adipic acid, all azelaic acid, all succinic acid and all terephthalic acid fed to the reactor, thus corresponding to a Ti / P ratio of 5 by weight) are obtained. The reactor temperature is then increased to 257°C and gradually depressurized to below 1.2 mbar over 60 minutes. After about 4.30 hours of reaction, which is the time required to obtain PBTAdAzSuc with MFR 6.0 g / 10 min (190°C, 2.16 kg), it is discharged in a string into a water bath and granulated.

[0065] Example 7 (Comparative) - Preparation of poly(1,4-butylene sebacate-co-1,4-butylene azelate-co-1,4-butylene succinate-co-1,4-butylene terephthalate) [PBTSebAzSuc 33.3 / 33.3 / 33.3] using 40 mol % terephthalic acid based on total carboxylic acids, 33.3 mol % sebacic acid, 33.3 mol % azelaic acid, and 33.3 mol % succinic acid based on total carboxylic acids.

[0066] Esterification process A steel reactor of geometric volume 60 liters, equipped with a mechanical stirring system, nitrogen inlet, distillation column, high boiling distillate knockdown system, and connection to a high vacuum system, was charged with the following in a diol to dicarboxylic acid molar ratio (MGR) of 1: 44.82 g terephthalic acid, 27.27 g sebacic acid, 25.38 g azelaic acid, 15.93 g succinic acid, 121.50 g 1,4-butanediol, and 0.23 g tetrabutyl titanate (Tyzor TnBT, equivalent to 215 ppm metals relative to the amount of PBTSebAzSuc theoretically obtained by converting all sebacic acid, all azelaic acid, all succinic acid, and terephthalic acid fed to the reactor). The mass temperatures were maintained at 190°C, 200°C and 210°C for 1 hour, 2 hours and 1 hour respectively.

[0067] Polycondensation Phase The reactor temperature was then increased to 240° C. and gradually reduced pressure to 2 mbar over 45 min. The reaction was allowed to react for approximately 4 h, which was the time required to obtain PBTSebAzSuc with MFR of 5.7 g / 10 min (190° C., 2.16 kg), after which the material was discharged. [Table 2]

[0068] From the data in Table 1, comparing Example 2 with Comparative Example 1, it can be seen that when azelaic acid is in the presence of succinic acid and another saturated aliphatic dicarboxylic acid (adipic acid), the Tg of the mixed aliphatic-aromatic polyester is surprisingly lower than the Tg of the mixed aliphatic-aromatic polyester containing succinic acid and sebacic acid. This effect was also confirmed with four acids in the presence of azelaic acid and succinic acid (Example 3). This effect is even more surprising considering that it does not occur when only two saturated aliphatic dicarboxylic acids are present, in agreement with what has been described in the literature (Comparative Example 4 vs. Comparative Example 5). Comparative Example 7 (Prior Art, Pan et al.) confirms that the combination of azelaic acid, succinic acid and sebacic acid exhibits a ratio of cyclic oligomers containing at least two dicarboxylic aliphatic units having a MM of less than 1000 to cyclic oligomers containing only one dicarboxylic aliphatic unit having a MM of less than 1000 (ratio between mixed cyclic oligomers) of 1.62, which is outside the scope of the present invention.

Claims

1. a) a dicarboxylic acid component, i. a1) 40 to 80 mol % of units derived from at least one aromatic dicarboxylic acid; ii. a2) 20 to 60 mol % of units derived from at least three C4 to C24 saturated dicarboxylic acids, including azelaic acid and succinic acid, their C1 to C24 alkyl esters, their salts, and mixtures thereof Dicarboxylic acid component containing b) Diol Aliphatic Component a2. A mixed aliphatic-aromatic polyester comprising: a) a copolymer of a cyclic aliphatic copolymer and a dicarboxylic acid aliphatic unit; b) a copolymer of a cyclic aliphatic unit and a dicarboxylic acid aliphatic unit; c) a copolymer of a cyclic aliphatic unit and a dicarboxylic acid aliphatic unit; d) a copolymer of a cyclic aliphatic unit and a dicarboxylic acid aliphatic unit; e) a copolymer of a cyclic aliphatic unit and a dicarboxylic acid aliphatic unit; f) a copolymer of a cyclic aliphatic unit and a dicarboxylic acid aliphatic unit; g) a copolymer of a cyclic aliphatic unit and a dicarboxylic acid aliphatic unit;

2. 10. The mixed aliphatic-aromatic polyester of claim 1, wherein the residual cyclic mixed oligomer content is between 2.0% and 3.5%.

3. 2. The mixed aliphatic-aromatic polyester of claim 1, wherein the diol aliphatic component b) comprises at least 50 mole % of one or more diols selected from 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol.

4. 2. The mixed aliphatic-aromatic polyester according to claim 1, wherein the dicarboxylic acid component a) comprises 40 to 75 mol %, more preferably 42 to 52 mol %, even more preferably 45 to 49 mol %, based on the total dicarboxylic acid component, of units derived from at least an aromatic dicarboxylic acid (component a1) and 25 to 60 mol %, more preferably 45 to 58 mol %, even more preferably 51 mol % to 55 mol %, based on the total dicarboxylic acid component, of units derived from at least three saturated aliphatic dicarboxylic acids (component a2).

5. 2. The mixed aliphatic-aromatic polyester according to claim 1, wherein the mole percentage of saturated aliphatic dicarboxylic acids of renewable origin in component a2) is preferably 30% or more, more preferably 40% or more, even more preferably 50% or more, based on the sum of all saturated dicarboxylic acids.

6. 2. The mixed aliphatic-aromatic polyester according to claim 1, further characterized in that the succinic acid of component a2) is comprised between 5 mol% and 67 mol%, preferably between 10 mol% and 50 mol%, and even more preferably between 20 mol% and 35 mol%, relative to the sum of all saturated dicarboxylic acids.

7. 2. The mixed aliphatic-aromatic polyester according to claim 1, wherein the azelaic acid of component a2) is preferably contained in an amount of 3 mol% to 92 mol%, more preferably 10 mol% to 50 mol%, and even more preferably 15 mol% to 35 mol%, based on the sum of all saturated dicarboxylic acids.

8. 2. Mixed aliphatic-aromatic polyesters according to claim 1, wherein the saturated aliphatic dicarboxylic acids of component a2) are advantageously chosen from C4-C24, preferably C4-C13, more preferably C4-C11 saturated dicarboxylic acids, their C1-C24, preferably C1-C4 alkyl esters, their salts and mixtures thereof.

9. 9. The mixed aliphatic-aromatic polyester according to claim 8, wherein the saturated aliphatic dicarboxylic acids of component a2) are advantageously selected from succinic acid, glutaric acid, 2-methylglutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanoic acid, dodecanoic acid, brassylic acid, and their C1-C24 alkyl esters.

10. 2. Mixed aliphatic-aromatic polyester according to claim 1, characterized in that it comprises repeating units derived from an aromatic dicarboxylic acid of the phthalic acid type, preferably terephthalic acid, an aromatic dicarboxylic acid and an aliphatic diol (AAPE-A), the content of aromatic units being between 42 and 52 mol %, preferably between 45 and 49 mol %, relative to the total number of moles of the dicarboxylic acid components.

11. 2. The mixed aliphatic-aromatic polyester according to claim 1, comprising repeating units derived from 2,5-furandicarboxylic acid, an aromatic dicarboxylic acid and an aliphatic diol (AAPE-B), characterized in that the content of aromatic units is 40 to 80 mol %, preferably 40 to 75 mol %, relative to the total number of moles of the dicarboxylic acid components.

12. (ADA-BDO)2, (AZA-BDO)2, (SEBA-BDO)2, (BRA-BDO)2, (SUC-BDO)2, (ADA-BDO)3, (AZA-BDO)3, (SEBA-BDO)3, (BRA-BDO)3, (SUC-BDO)3, (ADA-BDO)4, (AZA-BDO)4, (SUC-BDO)4 (wherein ADA corresponds to an ester of adipic acid and a diol component, and AZA corresponds to an ester of azelaic acid and a diol component).

2. The mixed aliphatic-aromatic polyester of claim 1, comprising a cyclic oligomer containing only one type of aliphatic dicarboxylic acid unit selected from the group consisting of (a) esters of succinic acid and diol components, (b) esters of sebacic acid and diol components, (c) esters of terephthalic acid and diol components, (d) esters of sebacic acid and diol components, (e) esters of sebacic acid and diol components, (f) esters of terephthalic acid and diol components, (g) esters of terephthalic acid and diol components, (h) esters of terephthalic acid and diol components, (i) esters of terephthalic acid and diol components, (j ... and (k) esters of terephthalic acid and diol components, and (k) esters of terephthalic acid and diol components, and (k) esters of terephthalic acid and diol components, and (k) esters of terephthalic acid and diol components, and (k) esters of terephthalic acid and

13. (ADA-BDO-AZA-BDO)、(ADA-BDO-SEBA-BDO)、(ADA-BDO-BRA-BDO)、(ADA-BDO-SUC-BDO)、(AZA-BDO-SEBA-BDO)、(AZA-BDO-BRA-BDO)、(AZA-BDO-SU) C-BDO)、(SEBA-BDO-BRA-BDO)、(SEBA-BDO-SUC-BDO)、(SUC-BDO-BRA-BDO)、(ADA-BDO)2-(AZA-BDO)、(ADA-BDO)-(AZA-BDO)2、(ADA-BDO)2-(SEBA -BDO)、(ADA-BDO)-(SEBA-BDO)2、(ADA-BDO)2-(BRA-BDO)、(ADA-BDO)-(BRA-BDO)2、(ADA-BDO)2-(SUC-BDO)、(ADA-BDO)-(SUC-BDO)2、(AZA-BDO) 2-(SUC-BDO)、(AZA-BDO)-(SUC-BDO)2、(SEB-BDO)2-(SUC-BDO)、(SEB-BDO)-(SUC-BDO)2、(BRA-BDO)2-(SUC-BDO)、(BRA-BDO)-(SUC-BDO)2、(AZA- (BDO)2-(SEBA-BDO)、(AZA-BDO)-(SEBA-BDO)2、(AZA-BDO)2-(BRA-BDO)、(AZA-BDO)-(BRA-BDO)2、(SEBA-BDO)2-(BRA-BDO)、(SEBA-BDO)-(BRA-BDO)2、(ADA-BDO)-(PTA-BDO)-(AZ-BDO)、(ADA-BDO)-(PTA-BDO)-(SEBA-BDO)、(ADA-BDO)-(PTA-BDO)-(BRA-BDO)、(SEBA-BDO)-(PTA-BDO)-(AZ-BDO (BRA-BDO)-(PTA-BDO)-(AZ-BDO)-(BRA-BDO)-(PTA-BDO)-(SEBA-BDO)-(ADA-BDO)-(PTA-BDO)-(SUC-BDO)-(AZA-BDO)-(PTA-BDO)-(SUC-BDO)-(SEB-BDO)-(PTA-BDO)-(SUC-BDO)-(ADA-BDO)-(AZA-BDO)-(SEBA-BDO)-(ADA-BDO)-(AZA-BDO)-(BRA-BDO)(ADA-BDO)-(BRA-BDO)-(SEBA-BDO), (BRA-BDO)-(AZA-BDO)-(SEBA-BDO), (ADA-BDO)-(AZA-BDO)-(SUC-BDO), (SEBA-BDO)-(AZA-BDO)-(SUC-BDO), (BRA-BDO)-( AZA-BDO)-(SUC-BDO), (SEBA-BDO)-(BRA-BDO)-(SUC-BDO), (SEBA-BDO)-(ADA-BDO)-(SUC-BDO), (ADA-BDO)2-(AZA-BDO)2, (ADA-BDO)2-(SEBA-BDO)2, (ADA-BDO) 2-(BRA-BDO)2 (wherein ADA corresponds to an ester of adipic acid with a diol component, AZA corresponds to an ester of azelaic acid with a diol component, SUC corresponds to an ester of succinic acid with a diol component, SEBA corresponds to an ester of sebacic acid with a diol component, BRA corresponds to an ester of brassylic acid with a diol component, PTA corresponds to an ester of terephthalic acid with a diol component, and BDO corresponds to the diol component 1,4 butanediol), the mixed aliphatic-aromatic polyester according to claim 1, comprising a cyclic oligomer containing at least two aliphatic dicarboxylic acid units selected from the group consisting of 2-(BRA-BDO)2,

14. Mixtures of mixed aliphatic-aromatic polyesters according to any one of claims 1 to 13 with other biodegradable polymers of synthetic and natural origin and, optionally, polyhydroxyalkanoates, inorganic fillers, crosslinkers and / or chain extenders.

15. i) 30 to 95% by weight, based on the sum of components i to v, of at least one mixed aliphatic-aromatic polyester; ii) 0.1 to 50% by weight, based on the sum of components i.-v., of at least one polymer of natural origin; iii) 0 to 40% by weight, based on the sum of components i.-v., of at least one polyhydroxyalkanoate; iv) 0 to 15% by weight, based on the sum of components i.-v., of at least one inorganic filler; v) 0 to 5% by weight of at least one crosslinker and / or chain extender comprising at least one difunctional and / or polyfunctional compound having isocyanates, peroxides, carbodiimides, isocyanurates, oxazolines, epoxides, anhydrides, divinyl ethers and mixtures thereof 15. A film obtained using the blend of mixed aliphatic-aromatic polyesters according to claim 14, comprising:

16. 14. An article comprising the mixed aliphatic-aromatic polyester of claims 1 to 13, - single-layer and double-layer oriented films, as well as multilayer films with other polymeric materials; - Films used in the agricultural sector as mulching films; -Stretch films, including thin films for food, agricultural bales and waste packaging; - Bags and linings for organic matter collection, such as food waste and grass clipping collection; - Thermoformed food packaging, both single and multi-layer, such as containers for milk, yogurt, meat, beverages, etc.; - coating materials obtained by extrusion coating technology; - multilayer laminates having layers of cardboard, plastic material, aluminum, and metallized film; - Expanded or expandable beads for the production of parts formed by sintering; - expanded and semi-expanded products, including expanded blocks formed from pre-expanded particles; - intumescent sheets obtained for food packaging, thermoformed intumescent sheets and containers obtained therefrom; - containers for fruits and vegetables in general; - products chosen from compositions containing as fillers gelatinized, destructured and / or complex starches, native starches, wheat flour, other fillers of natural, vegetable or inorganic origin.