POLYMER COMPOSITION FOR THE MANUFACTURE OF THERMOFORMED ARTICLES

Abstract

This invention relates to a polymer composition that is particularly suitable for use in the manufacture of thermoformed articles, which can be biodegraded in industrial composting. This invention also relates to a process for the production of the said composition and articles obtained thereby.

Claims

1. A polymer composition for the production of thermoformed articles comprising, with respect to the sum of components i.-iv.: i) 20-60% by weight of at least one polyester i., comprising: a) a dicarboxylic component comprising with respect to the total dicarboxylic component: a1) 0-20% in moles of units deriving from at least one aromatic dicarboxylic acid, a2) 80-100% in moles of units deriving from at least one saturated aliphatic dicarboxylic acid, a3) 0-5% in moles of units deriving from at least one unsaturated aliphatic dicarboxylic acid; b) a diol component comprising, with respect to the total diol component: b1) 95-100% in moles of units deriving from at least one saturated aliphatic diol; b2) 0-5% in moles of units deriving from at least one unsaturated aliphatic diol; ii) 5-35% by weight of at least one polyhydroxyalkanoate; iii) 0.01-5% by weight of at least one cross-linking agent and/or a chain extender comprising at least one compound having di- and/or multiple functional groups selected from isocyanate, peroxide, carbodiimide, isocyanurate, oxazoline, epoxy, anhydride, divinyl ether groups and mixtures thereof; iv) 5-50% by weight of at least one mineral filler agent present in the form of particles having a median diameter of less than 1.5 microns, measured by Sedigraph according to IS013317-3; further comprising at least one polyester of diacid diol other than polyester i), comprising: a) a dicarboxylic component comprising, with respect to the total dicarboxylic component: a1) 20-100% in moles of units deriving from at least one aromatic dicarboxylic acid, a2) 0-80% in moles of units deriving from at least one saturated aliphatic dicarboxylic acid, a3) 0-5% in moles of units deriving from at least one unsaturated aliphatic dicarboxylic acid; b) a diol component comprising, with respect to the total diol component: b1) 95-100% in moles of units deriving from at least one saturated aliphatic diol; b2) 0-5% in moles of units deriving from at least one unsaturated aliphatic diol.

2. The polymer composition according to claim 1, wherein said at least one polyester i) comprises an aliphatic polyester (AP), comprising a dicarboxylic component consisting of, with respect to the total moles of the dicarboxylic component, 95-100% in moles of units deriving from at least one saturated aliphatic dicarboxylic acid and 0-5% in moles of units deriving from at least one unsaturated aliphatic dicarboxylic acid and a diol component comprising, with respect to the total moles of the diol component, 95-100% in moles of units deriving from at least one saturated aliphatic diol and 0-5% in moles of units deriving from at least one unsaturated aliphatic diol.

3. The polymer composition according to claim 2, wherein said aliphatic polyester (AP) is selected from the group consisting of poly(1,4-butylene succinate), poly(1,4-butylene adipate), poly(1,4-butylene azelate), poly(1,4-butylene sebacate), poly(1,4-butylene adipate-co-1,4-butylene succinate), poly(1,4-butylene azelate-co-1,4-butylene succinate), poly(1,4-butylene sebacate-co-1,4-butylene succinate), poly(1,4-butylene succinate-co-1,4-butylene adipate-co-1,4-butylene azelate).

4. The polymer composition according to claim 3, wherein said aliphatic polyester (AP) is poly(1,4-butylene succinate).

5. The polymer composition according to claim 1, wherein the aromatic dicarboxylic acids of said polyesters of diacid diol other than polyester i) are selected from aromatic dicarboxylic acids of the phthalic acid type and heterocyclic dicarboxylic acids, their esters, their salts and their mixtures.

6. The polymer composition according to claim 1 wherein the saturated aliphatic dicarboxylic acids of said polyesters of diacid diol other than polyester i), are selected from C.sub.2-C.sub.24 saturated dicarboxylic acids, their C.sub.1-C.sub.24 alkyl esters, their salts and their mixtures.

7. The polymer composition according to claim 6, wherein the saturated aliphatic dicarboxylic acids of said polyesters of diacid diol other than polyester i) are selected from: succinic acid, 2-ethylsuccinic acid, glutaric acid, 2-methylglutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecandioic acid, dodecandioic acid, brassylic acid and their C.sub.1-C.sub.24 alkyl esters.

8. The polymer composition according to claim 7, wherein the saturated aliphatic dicarboxylic acids of said polyesters of diacid diol other than polyester i), comprise mixtures comprising at least 50% in moles of succinic acid, adipic acid, azelaic acid, sebacic acid, brassylic acid, their C.sub.1-C.sub.24 esters and their mixtures.

9. The polymer composition according to claim 1, wherein said at least one polyhydroxyalkanoate ii. is selected from the group consisting of polyesters of lactic acid, poly-s-caprolactone, polyhydroxybutyrate, polyhydroxybutyrate-valerate, pol yhydroxybutyrate propanoate, polyhydroxybutyrate-hexanoate, polyh ydroxybutyrate-decanoate, polyhydroxybutyrate-dodecanoate, polyhydroxybutyrate-esadecanoate, polyhydroxybutyrate-ottadecanoate, poly-3-hydroxybutyrate 4-hydroxybutyrate.

10. The polymer composition according to claim 1, wherein said at least one mineral filler agent iv) is talc.

11. The polymer composition according to claim 10, wherein said mineral filler agent is present in the form of particles having a median diameter of less than 1.2 microns.

12. A thermoformed article comprising the polymer composition according to claim 1.

13. The thermoformed articles according to claim 12, selected from the group consisting of plates, cups, rigid containers, capsules for the dispensing of beverages, lids, covers, or containers for food which can be heated in conventional or microwave ovens.

14. The polymer composition according to claim 2, wherein the aromatic dicarboxylic acids of said polyesters of diacid diol other than polyester i) are selected from aromatic dicarboxylic acids of the phthalic acid type and heterocyclic dicarboxylic acids, their esters, their salts and their mixtures.

15. The polymer composition according to claim 3, wherein the aromatic dicarboxylic acids of said polyesters of diacid diol other than polyester i) are selected from aromatic dicarboxylic acids of the phthalic acid type and heterocyclic dicarboxylic acids, their esters, their salts and their mixtures.

16. The polymer composition according to claim 4, wherein the aromatic dicarboxylic acids of said polyesters of diacid diol other than polyester i) are selected from aromatic dicarboxylic acids of the phthalic acid type and heterocyclic dicarboxylic acids, their esters, their salts and their mixtures.

17. The polymer composition according to claim 2 wherein the saturated aliphatic dicarboxylic acids of said polyesters of diacid diol other than polyester i), are selected from C.sub.2-C.sub.24 saturated dicarboxylic acids, their C.sub.1-C.sub.24 alkyl esters, their salts and their mixtures.

18. The polymer composition according to claim 3 wherein the saturated aliphatic dicarboxylic acids of said polyesters of diacid diol other than polyester i), are selected from C.sub.2-C.sub.24 saturated dicarboxylic acids, their C.sub.1-C.sub.24 alkyl esters, their salts and their mixtures.

19. The polymer composition according to claim 4 wherein the saturated aliphatic dicarboxylic acids of said polyesters of diacid diol other than polyester i), are selected from C.sub.2-C.sub.24 saturated dicarboxylic acids, their C.sub.1-C.sub.24 alkyl esters, their salts and their mixtures.

20. The polymer composition according to claim 5 wherein the saturated aliphatic dicarboxylic acids of said polyesters of diacid diol other than polyester i), are selected from C.sub.2-C.sub.24 saturated dicarboxylic acids, their C.sub.1-C.sub.24 alkyl esters, their salts and their mixtures.

Description

EXAMPLES

Component i

[0098] i-1=Poly(1,4-butylene succinate) (“PBS”) prepared according to the following method: 17150 g of succinic acid, 14000 g of 1,4-butandiol, 26.75 g of glycerine and 2.0 g of an 80% by weight ethanolic solution of diisopropyl triethanolamine titanate (Tyzor TE, containing 8.2% by weight of titanium) were added to a steel reactor having a geometrical capacity of 40 litres fitted with a mechanical stirring system, an inlet for nitrogen, a distillation column, a knock-down system for high boiling point components and a connection to a high vacuum system in a diol/dicarboxylic acid (MGR) molar ratio of 1.08. The temperature of the mass was gradually raised to 230° C. over a period of 120 minutes. When 95% of the theoretical water has been distilled off, 21.25 g of tetra n-butyl titanate (corresponding to 119 ppm of metal with respect to the quantities of poly 1,4-butylene succinate that would be theorically obtainable by converting all the succinic acid fed to the reactor) were added. The temperature of the reactor was then raised to 235-240° C. and the pressure was gradually reduced to a value below 2 mbar over a period of 60 minutes. The reaction was allowed to proceed for the time required to obtain a poly(1,4-butylene succinate) with an MFR of approximately 7 (g/10 minutes at 190° C. and 2.16 kg), and the material was then discharged in the form of a filament into a water bath and granulated. [0099] i-2=Poly(1,4-butylene sebacate-co-1,4-butylene terephthalate) (“PBST”) was prepared according to the following method: 8160 g of terephthalic acid, 11198 g of sebacic acid, 11296 g of 1,4-butanediol, 14.4 g of glycerine and 2.0 g of an 80% by weight ethanolic solution of diisopropyl triethanolamine titanate (Tyzor TE, containing 8.2% by weight of Titanium) were added in a diol/dicarboxylic acid molar ratio (MGR) of 1.20 to a steel reactor having a geometrical capacity of 40 litres, fitted with a mechanical stirrer system, an inlet for nitrogen, a distillation column, a knock-down system for high-volume distillates and a connection to a high vacuum system. The temperature of the mass was gradually increased to 230° C. over a period of 120 minutes. When 95% of the theoretical water had been distilled off, 21.2 g (corresponding to 119 ppm of metal with respect to the quantity of PBST which could theoretically be obtained by converting all the sebacic acid and all the terephthalic acid fed to the reactor) of tetra n-butyl Titanate was added. The temperature of the reactor was then raised to 235-240° C. and the pressure was gradually reduced until a value of less than 2 mbar was reached over a period of 60 minutes. The reaction was allowed to proceed for the time required to obtain a poly(1,4-butylene sebacate-co-1,4-butylene terephthalate) with an MFR of approximately 5 (g/10 minutes at 190° C. and 2.16 kg), and the material was then discharged in the form of a filament into a water bath and granulated.

Component ii

[0100] ii=Ingeo 4043D polylactic acid (“PLA”), MFR 3.5/10 min (at 190° C., 2.16 kg).

Component iii

[0101] iii-1=HMV-15CA Carbodilite from Nisshinbo Chemical Inc.; [0102] iii-2=Luperox F40MG (1,3-1,4-bis(tert-butylperoxyisopropyl)-benzene in EPM rubber) from Arkema; [0103] iii-3=masterbatch comprising 10% by weight of Joncryl ADR4368CS (styrene—glycidylether-methylmethacrylate copolymer) and 90% by weight of component ii.

Component iv

[0104] iv=micronised talc having a median diameter of 1 microns (particle size distribution by Sedigraph according to ISO 13317-3), Jetfine 3CA commercial grade from Imerys.

[0105] EXAMPLES 1-4— Production of thermoformed articles comprising the composition according to this invention.

TABLE-US-00001 TABLE 1 Compositions in Examples 1-4. Components (% wt) Example i-1 i-2 ii iii-1 iii-2 iii-3 iv 1 47.7 — 16 0.2 36.1 2 42.7 5 16 0.2 36.1 3 47.7 — 16 — 0.2 — 36.1 4 47.7 — 14.7 — — 1.5 36.1

[0106] The composition in Table 1 was fed to an Icma San Giorgio MCM 25 HT model co-rotating twin screw extruder under the following operating conditions:

[0107] Screw diameter (D)=25 mm;

[0108] L/D=52;

[0109] Rotation speed=200 rpm;

[0110] Temperature profile=100-180-215x9-180-170-160° C.;

[0111] Throughput 10.1 kg/h;

[0112] Degassing under vacuum;

[0113] The granules were fed to a Curti single-screw extruder (screw diameter 40 mm— L/D 25) equipped with a flat head 400 mm wide and Teknomast compound rolling unit of 3 rolls of width 400 and diameter 200—and provided with water cooling. The operating conditions were as follows:

[0114] Screw diameter (D)=40 mm;

[0115] L/D=25;

[0116] Rotation speed=60 rpm;

[0117] Temperature profile=Extruder: 190-5x200° C./Head: 6x200° C.;

[0118] Throughput 20 kg/h.

[0119] From the sheets were obtained bars (length 30 mm, width 6 mm, thickness 0.5 mm) which then underwent dynamic mechanical-torsional analysis (DMTA) in torsional mode using an Ares G2 rotational rheometer from TA Instrument. The samples were heated from 30° C. to 120° C. at 3° C./min imposing a deformation of 0.1% and a frequency of 1 Hz.

[0120] Heat deflection temperature (HDT) was measured according to standard ASTM-D648 using a 0.455 MPa load (Method B), on moulded test specimens of the “bar” type (length 127 mm, width 12.7 mm, thickness 3.2 mm) using Ceast 6510 Test-A-Matic model equipment. HDT values were determined in triplicate for each composition. The value stated corresponds to the arithmetic mean of the measured values.

[0121] Sheets of 350 μm thickness were thermoformed on an Artpack thermoforming machine in a single die mould for the production of plates (diameter 220 mm, depth 40 mm) using the following thermoforming operating conditions: [0122] Heating by means of 15 IR lamps (rated maximum power of each lamp 325 W); [0123] Heating time 5-8 sec. (to softening); [0124] Total cycle time 15-20 sec.

[0125] The plates obtained underwent a disintegration test in controlled composting according to standard IS020200:2004, showing a weight loss of more than 90% over 90 days at 58° C.

TABLE-US-00002 TABLE 2 HDT and DMTA characterization. G′ [MPa] a G′ [MPa] a Example HDT ° C. T = 70° C. T = 90° C. 1 91 ± 1 471 374 2 91 ± 1 398 306 3 91 ± 1 421 322 4 91 ± 1 349 238