Polyester and compositions containing it

Abstract

This invention relates to a new polyester which is particularly suitable for use in the manufacture of mass-produced articles characterised by excellent mechanical properties, in particular high tensile strength and tensile modulus, associated with a high barrier property against oxygen and carbon dioxide.

Claims

1. A polyester comprising: a) a dicarboxylic component comprising with respect to the total dicarboxylic component: a1) 99-85% in moles of units deriving from 2,5-furandicarboxylic acid or an ester thereof; a2) 1-15% in moles of units deriving from at least one saturated dicarboxylic acid selected from the group comprising adipic acid, azelaic acid, sebacic acid, brassylic acid or an ester or derivative thereof; b) a diol component comprising with respect to the total diol component: b1) 95-100% in moles of units deriving from 1,2-ethanediol; b2) 0-5% in moles of units deriving from at least one saturated aliphatic diol which is not 1,2-ethanediol; b3) 0-5% in moles of units deriving from at least one unsaturated aliphatic diol, wherein the polyester has been subjected to a SSP process and has an inherent viscosity of more than 0.3 dl/g (measured using an Ubbelohde viscosity meter in 1:1 v/v dichloromethane-trifluoroacetic acid solution at a concentration of 0.5 g/dl at 25° C.); and a permeability of oxygen lower than $3\left[\frac{{\mathrm{cm}}^3\times \mathrm{mm}}{m^2\times 24h\times \mathrm{bar}}\right]$ measured at 23° C., 50% relative humidity according to ASTM F2622-08 and a permeability of carbon dioxide lower than $12\left[\frac{{\mathrm{cm}}^3\times \mathrm{mm}}{m^2\times 24h\times \mathrm{bar}}\right]$ according to ASTM F2476-05, said permeability of oxygen and said permeability of carbon dioxide being determined on cast films of thickness from 60-90 μm.

2. The polyester according to claim 1, wherein said dicarboxylic component a) comprises also: a3) 0-10% by moles of units deriving from at least one aliphatic saturated dicarboxylic acid which is not the saturated dicarboxylic acid in component a2).

3. The polyester according to claim 2, in which the said saturated aliphatic dicarboxylic acid (component a3) is selected from saturated C.sub.2-C.sub.24 dicarboxylic acids, their C.sub.1-C.sub.24 alkyl esters, their salts and their mixtures.

4. The polyester according to claim 3, in which the said saturated dicarboxylic acid in component a2 is azelaic acid.

5. The polyester according to claim 3, in which the said saturated aliphatic diol which is not 1,2-ethanediol (component b2) is selected from the group consisting of 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-cyclohexandimethanol, neopentylglycol, 2-methyl-1,3-propanediol, dianhydrosorbitol, dianhydromannitol, dianhydroiditol, cyclohexanediol, cyclohexanemethanediol, dialkylene glycols and polyalkylene glycols having a molecular weight of 100-4000 measured by gel permeation chromatography, polypropylene glycol and mixtures thereof.

6. The polyester according to claim 2, in which the said dicarboxylic acid in component a3 is selected from the group consisting of succinic acid, 2-ethylsuccinic acid, glutaric acid, 2-methylglutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, undecandioic acid, dodecandioic acid, brassylic acid and their C.sub.1-C.sub.24 alkyl esters.

7. The polyester according to claim 6, in which the said saturated aliphatic diol which is not 1,2-ethanediol (component b2) is selected from the group consisting of 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-cyclohexandimethanol, neopentylglycol, 2-methyl-1,3-propanediol, dianhydrosorbitol, dianhydromannitol, dianhydroiditol, cyclohexanediol, cyclohexanemethanediol, dialkylene glycols and polyalkylene glycols having a molecular weight of 100-4000 measured by gel permeation chromatography, polypropylene glycol and mixtures thereof.

8. The polyester according to claim 7, in which the said saturated dicarboxylic acid in component a2 is azelaic acid.

9. The polyester according to claim 2, in which the said saturated aliphatic diol which is not 1,2-ethanediol (component b2) is selected from the group consisting of 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-cyclohexandimethanol, neopentylglycol, 2-methyl-1,3-propanediol, dianhydrosorbitol, dianhydromannitol, dianhydroiditol, cyclohexanediol, cyclohexanemethanediol, dialkylene glycols and polyalkylene glycols having a molecular weight of 100-4000 measured by gel permeation chromatography, polypropylene glycol and mixtures thereof.

10. The polyester according to claim 2, in which the said saturated dicarboxylic acid in component a2 is azelaic acid.

11. The polyester according to claim 1, wherein said dicarboxylic component a) comprises also: a4) 0-5% by moles of units deriving from at least one unsaturated aliphatic dicarboxylic acid or an ester thereof.

12. The polyester according to claim 11, in which the said saturated aliphatic diol which is not 1,2-ethanediol (component b2) is selected from the group consisting of 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-cyclohexandimethanol, neopentylglycol, 2-methyl-1,3-propanediol, dianhydrosorbitol, dianhydromannitol, dianhydroiditol, cyclohexanediol, cyclohexanemethanediol, dialkylene glycols and polyalkylene glycols having a molecular weight of 100-4000 measured by gel permeation chromatography, polypropylene glycol and mixtures thereof.

13. The polyester according to claim 11, in which the said saturated dicarboxylic acid in component a2 is azelaic acid.

14. The polyester according to claim 1, in which the said saturated dicarboxylic acid in component a2 is azelaic acid.

15. The polyester according to claim 14, in which the said saturated aliphatic diol which is not 1,2-ethanediol (component b2) is selected from the group consisting of 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-cyclohexandimethanol, neopentylglycol, 2-methyl-1,3-propanediol, dianhydrosorbitol, dianhydromannitol, dianhydroiditol, cyclohexanediol, cyclohexanemethanediol, dialkylene glycols and polyalkylene glycols having a molecular weight of 100-4000 measured by gel permeation chromatography, polypropylene glycol and mixtures thereof.

16. The polyester according to claim 1, in which the said saturated aliphatic diol which is not 1,2-ethanediol (component b2) is selected from the group consisting of 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-cyclohexandimethanol, neopentylglycol, 2-methyl-1,3-propanediol, dianhydrosorbitol, dianhydromannitol, dianhydroiditol, cyclohexanediol, cyclohexanemethanediol, dialkylene glycols and polyalkylene glycols having a molecular weight of 100-4000 measured by gel permeation chromatography, polypropylene glycol and mixtures thereof.

17. A film, nonwoven fabric, sheet, moulded, thermoformed, blow moulded expanded or laminated article comprising the polyester according to claim 1.

18. A composition comprising the polyester according to claim 1.

19. The composition according to claim 18, comprising with respect to the sum of components i.-v.: i) 1-99% by weight of at least one of said polyester; ii) 99-1% by weight of at least one polymer of synthetic or natural origin, which may or may not be biodegradable and which is other than said polyester; iii) 0-5% by weight of at least one cross-linking agent and/or chain extender comprising at least one compound having two and/or multiple functional groups including isocyanate, peroxide, carbodiimide, isocyanurate, oxazoline, epoxide, anhydride or divinyl ether groups and mixtures thereof; iv) 0-50% by weight of at least one filler; v) 0-30% by weight of plant fibres.

20. A film, nonwoven fabric, sheet, moulded, thermoformed, blow moulded expanded or laminated article comprising the composition according to claim 19.

21. The polyester according to claim 1, which has a ΔH.sub.m value of 20-60 J/g.

22. The polyester according to claim 1, wherein the SSP is performed by crystallizing the polyester in an oven at 10-60° C. below its melting point under vacuum of p<2 mbar for 2-150 hours or under nitrogen flow; and after crystallization stage the temperature is raised to 10-30° C. below melting point under vacuum, until the desired viscosity is reached.

Description

EXAMPLES

(1) Synthesis of Polyesters

(2) The reagents 2,5-furandicarboxylic acid, azelaic acid or sebacic acid and 1,2-ethanediol and the esterification catalyst (Tyzor TE®) were loaded into a 25 geometrical litre steel reactor provided with oil heating, a distillation column, a vacuum line with a distillates knock-down system and mechanical stirring, in the proportions shown in Table 1.

(3) The reactor was sealed and 3 vacuum/nitrogen cycles were carried out to remove the oxygen present. Subsequently the stirrer was switched on and the temperature was gradually raised to 220° C. over a time of 1 hour during which the water deriving from the esterification process began to distil off. The temperature was then raised to 238° C. for approximately a further hour.

(4) Distillation was allowed to proceed for 1 hour at 238° C., at the end of which the apparent conversion was 100% or more.

(5) Vacuum was gradually applied from atmospheric pressure to 100 mbar over approximately 30 minutes to complete the esterification.

(6) At the end of the esterification stage the reactor was returned to atmospheric pressure with nitrogen and then the polymerisation catalyst (1000 ppm of tetraorthobutyl zirconate, ToBZ) was added, the temperature of the melt was held at 238° C. and the pressure was gradually reduced to below 2 mbar over a time of approximately 30 minutes.

(7) The reaction was continued for 4 hours holding the temperature of the melt at 238° C. until the desired inherent viscosity was achieved.

(8) The material was then discharged as filaments through a spinner, cooled in a water bath and granulated into pellets.

(9) The pellets were then subjected to SSP: first they were crystallized in an oven at 10-60° C. below its melting point under vacuum (p<2 mbar) for 72-144 hours. After crystallization stage the temperature was raised to 10-30° C. below melting point and the vacuum was kept at 2 mbar until the desired viscosity was reached.

(10) TABLE-US-00001 TABLE 1 Synthesis of polyesters Inherent Inherent 2,5-furandicarboxylate Azelaic acid 1,2-ethanediol Tyzor viscosity viscosity g g g TE ToBZ before SSP*** after SSP*** T.sub.g Example (mol %*) (mol %*) (mol %**) ppm**** ppm**** dl/g dl/g ° C. 1 4682 297 3917 400 1000 0.70 0.87 71 (95%)  (5%) (100%) 2 4398 588 3884 400 1000 0.74 0.95 63 (90%) (10%) (100%) 3 4972 — 3952 400 1000 0.70 0.9 81 comparative (100%)  (100%) *mol % with respect to the sum of dicarboxylic components **mol % with respect to the sum of diol components ***measured using an Ubbelohde viscosity meter in 1:1 v/v dichloromethane-trifluoro acetic acid solution at a concentration of 0.5 g/dl at 25° C. ****quantity calculated with respect to the quantity of polyester which can be theoretically obtained by converting all the dicarboxylic acid fed to the synthesis process.

Example 4 (Comparative)

PET Cleartuf Turbo II

(11) Determination of the Barrier Properties Against Oxygen and Carbon Dioxide

(12) The barrier properties have been determined on casting films made with of 60-90 μm the polyesters prepared according to Examples 1-4.

(13) Films were prepared using polymer solution casting techniques. Polyesters prepared according to Examples 1-4 were dissolved in a mixture of hexafluoroisopropanol/dichloromethane, coated onto a substrate, then subjected to annealing at temperatures between 60 and 120° C. and with residence times of between 1 and 30 hours, in order to remove any residual trace of solvent,

(14) The barrier properties have been determined by permeability measurements carried out in a Extrasolution Multiperm permeabilimeter at 23° C.-50% relative humidity, according to standard ASTM F2622-08 for oxygen and standard ASTM F2476-05 for carbon dioxide.

(15) TABLE-US-00002 TABLE 2 Determination of barrier properties P (O.sub.2) P (CO.sub.2) Example $\left[\frac{{\mathrm{cm}}^3\times \mathrm{mm}}{m^2\times 24h\times \mathrm{bar}}\right]$ $\left[\frac{{\mathrm{cm}}^3\times \mathrm{mm}}{m^2\times 24h\times \mathrm{bar}}\right]$ 1 0.4 1.8 2 0.5 2.1 3 comparative 11.4 37 4 comparative 3.8 13.7
Mechanical Properties

(16) Mechanical properties were measured according to standard ASTM D790-03—Method B-V.sub.0=13 mm/min on standard test specimens of the “bar” type (length 127 mm, width 12.7 mm, thickness 3.2 mm) using an Instron 4301 model dynamometer. The following were determined: Maximum flexural strength (in MPa), strain at maximum strength (in %) and Flexural Modulus (in MPa).

(17) TABLE-US-00003 TABLE 3 Mechanical characterization according to ASTM-D790 Strain at Maximum flexural maximum strength strength Flexural Modulus Example (MPa) (%) (MPa) 1 132 5 3709 2 127 5.2 3420 3 comparative 141 5.2 3849 4 comparative 83 4.6 2473