BIODEGRADABLE POLYMER COMPOSITION FOR THE PRODUCTION OF MOLDED ITEMS

Abstract

Biodegradable polymer composition for the production of molded items comprising: i. 5-70% by weight of a polyester comprising units derived from an aromatic dicarboxylic acid, succinic acid and a C.sub.5-C.sub.24 saturated dicarboxylic acid; and units derived from a saturated aliphatic diol and an unsaturated aliphatic diol; ii 0-40% by weight of a polyester comprising units derived from succinic acid and units derived from a saturated aliphatic diol and an unsaturated aliphatic diol; iii. 23-43% by weight of a polyhydroxyalkanoate; iv. 10-20% by weight of a filler; v. 0-0.5% by weight of a cross-linking agent and/or chain extender.

Claims

1. A biodegradable polymer composition for the production of molded articles comprising, with respect to the total composition: i) 5-70% by weight, with respect to the sum of components i.-v., of at least one polyester comprising: a. dicarboxylic component comprising, in relation to the total dicarboxylic component, (a1) 0-20% by moles of units derived from at least one aromatic dicarboxylic acid (a2) 53-95% by moles of succinic acid units, (a3) 5-27% by moles of units derived from at least one saturated C.sub.5-C.sub.24 dicarboxylic acid b. a diol component comprising, compared to the total diol component: (b1) 95-100% by moles of units derived from at least one saturated aliphatic diol; (b2) 0-5% by moles of units derived from at least one unsaturated aliphatic diol; ii) 0-40% by weight, with respect to the sum of components i.-v., of at least one polyester comprising: c. a dicarboxylic component having 100% by moles of succinic acid d. a diol component comprising, compared to the total diol component: (d1) 95-100% by moles of units derived from at least one saturated aliphatic diol; (d2) 0-5% by moles of units derived from at least one unsaturated aliphatic diol; iii) 23-43% by weight of the sum of components i.-v., of at least one polyhydroxyalkanoate; iv) 10-20% by weight, relative to the sum of components i.-v., of at least one filler. v) 0-0.5% by weight, relative to the sum of components i.-v., of at least one cross-linking agent and/or chain extender; wherein component iii. has a melting point (Tm2)≥160° C. and a (ΔHm)≥10 J/g.

2. The biodegradable polymer composition for the production of molded articles according to claim 1 wherein polyester i) comprises one or more molecules with multiple functional groups, in amounts between 0.05 and 3% by moles to total moles of the dicarboxylic component, for the purpose of obtaining branched products.

3. The biodegradable polymer composition for producing molded articles according to claim 2 wherein the one or more molecules with multiple functional groups are chosen from the group consisting of glycerol, pentaerythritol, trimethylolpropane, citric acid, dipentaerythritol, monoanhydrosorbitol, monohydromannitol, acid triglycerides or polyglycerols.

4. The polymer composition for the production of molded articles according to claim 1 wherein saturated aliphatic dicarboxylic acids other than succinic acid (component a3) are selected from the group consisting of C.sub.5-C.sub.24, their C.sub.1-C.sub.24, alkyl esters, their salts and mixtures thereof.

5. The polymer composition for producing injection molded articles according to claim 1 wherein saturated aliphatic dicarboxylic acids other than succinic acid (component a3) are selected from the group consisting of: 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.

6. The polymer composition for the production of molded articles according to claim 1 wherein polyester i) comprises at least one aliphatic polyester (AP).

7. The polymer composition according to claim 1 for the production of molded articles wherein the aliphatic polyester i. is poly(1,4-butylene succinate-co-1,4 butylene azelate) and polyester ii. is poly(1,4-butylene succinate).

8. The polymer composition for producing molded articles according to claim 1 wherein the polyhydroxyalkanoate (component iii.) is selected from the group consisting of polyesters of lactic acid, polyhydroxybutyrate, polyhydroxybutyrate-valerate, polyhydroxybutyrate-propanoate, polyhydroxybutyrate-hexanoate, polyhydroxybutyrate-decanoate, polyhydroxybutyrate-dodecanoate, polyhydroxybutyrate-hexadecanoate, polyhydroxybutyrate-octadecanoate, and poly 3-hydroxybutyrate-4-hydroxybutyrate.

9. The polymer composition for producing molded articles according to claim 1 wherein the polyhydroxyalkanoate (component iii) has an enthalpy of fusion ΔHm) in the range from 10 to 93 J/g, and a Melting point in the range from 160 to 200° C.

10. The polymer composition for producing molded articles according to claim 1 wherein the polyhydroxyalkanoate (component iii) is a lactic acid polyester comprising at least 97% w/w of units derived from L-lactic acid, ≤3% w/w of repeating units derived from D-lactic acid, has a Melting point (Tm.sub.2) in the range 160-200° C., a Glass Transition Temperature (Tg) in the range 55-65° C. and a 1MFR (measured according to standard ASTM-D1238 at 210° C. and 2.16 kg) in the range 20-100 g/10 min.

11. The polymer composition for producing molded articles according to claim 1 wherein the filler (component iv) is selected from the group consisting of kaolin, wollastonite, barytes, clay, talc, calcium and magnesium carbonates, iron and lead carbonates, aluminum hydroxide, diatomaceous earth, aluminum sulfate, barium sulfate, silica, mica, titanium dioxide, starch, chitin, chitosan, alginates, proteins such as gluten, zein, casein, collagen, gelatin and natural gums.

12. The polymer composition for producing molded articles according to claim 1 wherein the filler (component iv.) is selected from the group consisting of talc, calcium carbonate, silica, kaolin, wollastonite, and mixtures thereof present in the form of particles having an arithmetic mean diameter, measured across the major axis of the particle of less than 10 microns.

13. The polymer composition for producing molded articles according to claim 1 wherein the crosslinking agent and/or chain extender (component v.) is selected from the group consisting of compounds having two or more functional groups bearing isocyanate, peroxide, carbodiimide, isocyanurate, oxazoline, epoxide, anhydride, divinylether groups and mixtures thereof.

14. A molded article comprising the polymer composition in claim 1 having properties of resistance to deformation at high temperature, and capable of disintegration according to EN13432 in thicknesses up to 1 mm.

15. A molded article comprising the polymer composition in claim 1 characterized by a THF content of less than 30 mg/kg thereby being capable of being used in contact with foodstuffs.

16. An article molded by injection molding comprising the polymer composition in claim 1 selected from the group consisting of disposable cutlery, plates and cups, rigid containers, capsules for dispensing beverages, caps and lids, packaging for food which can be heated in conventional and microwave ovens.

17. A thermoformed article comprising the polymer composition in claim 1 selected from the group consisting of containers, trays, plates, beverage dispensing capsules and printed circuit boards for electronics.

18. A process for the injection molding of articles according to claim 14 carried out in the absence of annealing heat treatment, wherein said articles are characterized by a conservative elastic modulus (G′) 70° C. of over 100 MPa.

19. The polymer composition for producing molded articles according to claim 2 wherein the polyhydroxyalkanoate (component iii.) is selected from the group consisting of polyesters of lactic acid, polyhydroxybutyrate, polyhydroxybutyrate-valerate, polyhydroxybutyrate-propanoate, polyhydroxybutyrate-hexanoate, polyhydroxybutyrate-decanoate, polyhydroxybutyrate-dodecanoate, polyhydroxybutyrate-hexadecanoate, polyhydroxybutyrate-octadecanoate, and poly 3-hydroxybutyrate-4-hydroxybutyrate.

20. The polymer composition for producing molded articles according to claim 3 wherein the polyhydroxyalkanoate (component iii.) is selected from the group consisting of polyesters of lactic acid, polyhydroxybutyrate, polyhydroxybutyrate-valerate, polyhydroxybutyrate-propanoate, polyhydroxybutyrate-hexanoate, polyhydroxybutyrate-decanoate, polyhydroxybutyrate-dodecanoate, polyhydroxybutyrate-hexadecanoate, polyhydroxybutyrate-octadecanoate, and poly 3-hydroxybutyrate-4-hydroxybutyrate.

Description

EXAMPLES:

[0151] Examples of Components i.-v. [0152] i-1=Poly(1,4-butylene succinate-co-azelate) (“PBSAz10”)

[0153] 11655 g of 1,4-butanediol, 11865 g of succinic acid, 2100 g of azelaic acid, 20.5 g of glycerin and 2.0 g of an 80% by weight ethanolic solution of diisopropyl triethanolamino titanate (containing 8.2% by weight of titanium) was loaded, in a diol/dicarboxylic acid molar ratio (MGR) of 1.15 into a steel reactor with a geometric capacity of 60 liters, equipped with a mechanical stirring system, an inlet for nitrogen, a distillation column, an abatement system for high boiling distillates and a connection to a high vacuum system. The temperature of the mass was gradually raised to 230° C. over a period of 120 minutes. When 95% of the theoretical water had been distilled, 20 g of tetra n-butyl titanate was added (corresponding to 140 ppm of metal compared to the amount of poly(1,4-butylene succinate) theoretically obtainable by converting all the succinic acid fed to the reactor). The reactor temperature was then raised to 235-240° C. and the pressure was gradually reduced to below 2 mbar over 60 minutes. The reaction was allowed to proceed for as long as necessary to obtain a poly(1,4-butylene succinate-co-1,4-butylene azelate) with an MFR of about 6 g/10 min (at 190° C. and 2.16 kg), and then the material was discharged into a water bath in the form of a strand and granulated. [0154] i-2=Poly(1,4-butylene succinate-co-azelate) (“PBSAz20”)

[0155] 11130 g of 1,4-butanediol, 10150 g of succinic acid, 4045 g of azelaic acid, 19,8 g of glycerin and 2,0 g of an 80% by weight ethanolic solution of diisopropyl triethanolamino titanate (containing 8.2% by weight of titanium) were loaded, in a diol/dicarboxylic acid molar ratio (MGR) of 1.15 into a steel reactor with a geometric capacity of 60 liters, equipped with a mechanical stirring system, an inlet for nitrogen, a distillation column, an abatement system for high boiling distillates and a connection to a high vacuum system. The temperature of the mass was gradually raised to 230° C. over a period of 120 minutes. When 95% of the theoretical water had been distilled off, 20 g of tetra n-butyl titanate is added (corresponding to 140 ppm of metal compared to the amount of poly(1,4-butylene succinate) theoretically obtainable by converting all the succinic acid fed to the reactor). The reactor temperature was then raised to 235-240° C. and the pressure was gradually reduced to below 2 mbar over 60 minutes. The reaction was allowed to proceed for as long as necessary to obtain a poly(1,4-butylene succinate-co-1,4-butylene azelate) with an MFR of about 8 g/10 min (at 190° C. and 2.16 kg), and then the material was discharged into a water bath in the form of a strand and granulated. [0156] ii-1=Poly(1,4-butylene succinate) (“PBS”).

[0157] 14000 g of 1,4-butanediol, 17150 g of succinic acid, 26.75 g of glycerin and 2.0 g of an 80% by weight ethanolic solution of diisopropyl triethanolamino titanate (containing 8.2% by weight of titanium) were loaded, in a diol/dicarboxylic acid molar ratio (MGR) of 1.08, into a steel reactor with a geometric capacity of 60 liters, equipped with a mechanical stirring system, an inlet for nitrogen, a distillation column, an abatement system for high boiling distillates and a connection to a high vacuum system. The temperature of the mass was gradually raised to 230° C. over a period of 120 minutes. When 95% of the theoretical water had been distilled off, 21.25 g tetra n-butyl titanate was added (corresponding to 119 ppm of metal compared to the amount of poly(1,4-butylene succinate) theoretically obtainable by converting all the succinic acid fed to the reactor). The reactor temperature was then raised to 235-240° C. and the pressure was gradually reduced to below 2 mbar over 60 minutes. The reaction was allowed to proceed for as long as necessary to obtain a poly(1,4-butylene succinate) with an MFR of approximately 7 g/10 min (at 190° C. and 2.16 kg), and then the material was discharged into a water bath in the form of a strand and granulated. [0158] vi-2=Poly(1,4-butylene adipate-co-1,4-butylene terephthalate) (“PBAT”) [0159] 7453 g of terephthalic acid, 7388 g of adipic acid, 12033 g of 1,4-butanediol, 4.4 g of glycerine and 3.4 g of a 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 1.40 to a steel reactor having a geometrical capacity of 60 litres fitted with a mechanical stirring system, an inlet for nitrogen, a distillation column, a knock-down system for high boiling point distillates and a connection to a high vacuum system. The temperature of the mass was gradually raised to 230° C. over a period of 120 minutes. When 95% of the theoretical water had been distilled off, 17.0 g of tetra n-butyl titanate (corresponding to 119 ppm of metal with respect to the quantity of poly(1,4-butylene adipate-co-1,4-butylene terephthalate) which could theoretically be obtained by converting all the adipic acid and the terephthalic acid fed to the reactor) were added. The temperature of the reactor was then raised to 235-240° C. and the pressure was reduced gradually to reach a value of less than 2 mbar over a period of 60 minutes. The reaction was allowed to proceed for the time necessary to obtain a poly (1,4-butylene adipate-co-1,4-butylene terephthalate) with a MFR of approximately 6 g/10 minutes, measured at 190° C. and 2.16 kg, and then the material was discharged into a water bath in the form of a string and granulated.

[0160] Examples of the production of injection molded articles comprising the composition according to the present invention; (1-2 invention, 3-4 comparative).

TABLE-US-00001 TABLE 1 Composition Examples 1-5 Example i-1 i-2 ii-1 iii-1 iii-2 iii-3 iii-4 iv-1 iv-2 iv-3 v-1 v-2 vi-1 vi-2 1 — 30 24.9 27.2 — — — 17.3 — — — — 0.6 — 2 54.9 — 27.2 — — — 17.3 — — — — 0.6 — 3 — 30 24.9 — — 27.2 — 17.3 — — — — 0.6 — (comparative) 4 — — 47.1 — — 16 — 36.1 — 0.2 — — — (comparative) 5 — — 55 — — — 25 — — 10 — — — 10 (comparative)

[0161] The composition in Table 1 was fed to a co-rotating twin-screw extruder model Icma San Giorgio MCM 25 HT operating under the following conditions: [0162] Screw diameter (D)=25 mm; [0163] L/D=52; [0164] Screw rotation=200 rpm; [0165] Thermal profile=110-150-190-200×5-190×3-170×3; [0166] Flow rate 10.1 kg/h; [0167] Vacuum degassing.

[0168] The granules obtained from the extrusion process were fed to an injection molding machine model Engel Victory120 for the production of wafers (width 70 mm, length 80 mm, thickness 1 mm) conforming to standard ISO 294-3 Type D1.

[0169] The operating conditions for obtaining 1 mm thick plates are described below:

[0170] Injection T° C.=200° C. (Ex. 1, 2 and 4), 190° C. (Ex. 3), 210° C. (Ex. 5);

[0171] Approx. filling pressure=1400 bar (Ex. 1, 2 and 4); 1300 bar (Ex. 3), 1600 bar (Ex. 5);

[0172] Approx. filling time=1 sec (Ex. 1, 2, 3, 4 and 5)

[0173] Holding or packing pressure=600 bar (Ex. 1, 2, 4 and 5); 400 bar (Ex. 3);

[0174] Holding time under packing pressure=5 sec (Ex. 1, 2, 4 and 5); 6 sec (Ex. 3);

[0175] Cooling time=9 sec (Ex. 1, 2, 4 and 5); 14 sec (Ex. 3);

[0176] Approx. cycle time=18 sec (Ex. 1, 2, 4 and 5); 24 sec (Ex. 3);

[0177] rpm=95 rpm (Ex. 1, 2, 3, 4 and 5);

[0178] Wafers with a width of 70 mm, a length of 80 mm and a thickness of 0.6 mm conforming to standard ISO 294-3 Type D1 were also produced by feeding the granules to an Engel Victoryl20 injection molding machine. The operating conditions for obtaining the 0.6 mm thick wafers are described below:

[0179] Injection T° C.=220° C. (Ex. 1, 2 and 4), 210° C. (Ex. 3), 240° C. (Ex. 5);

[0180] Approx. filling pressure=1200 bar (Ex. 1, 2 and 4); 900 bar (Ex. 3), 1400 bar (Ex. 5);

[0181] Approx. filling time=0.5 sec (Ex. 1, 2, 3, 4 and 5)

[0182] Holding or packing pressure=800 bar (Ex. 1, 2, 4 and 5); 500 bar (Ex. 3);

[0183] Holding time under packing pressure=4 sec (Ex. 1, 2, 4 and 5); 5 sec (Ex. 3);

[0184] Cooling time=10 sec (Ex. 1, 2, 4 and 5); 15 sec (Ex. 3);

[0185] Approx. cycletime=20 sec (Ex. 1, 2, 4 and 5); 25 sec (Ex. 3);

[0186] rpm=95 rpm (Ex. 1, 2, 3, 4 and 5);

[0187] From the plates (length 80 mm, width 70 mm) with thicknesses of 1 mm and 0.6 mm obtained by injection, bars (length 30 mm, width 6 mm) having both thicknesses were obtained. They were then subjected to dynamic-mechanical analysis (DMTA) in torsional mode using a TA Instrument's Ares G2 rotational rheometer. The samples were heated at 3° C./min from 25° C. to 120° C. imposing a strain of 0.1% and a frequency of 1 Hz. The injection molded compositions were characterized at 70° C.

TABLE-US-00002 TABLE 2 DMTA characterization G′ @ 70° C. (Mpa) Plate thickness Plate thickness Examples 1 mm 0.6 mm 1 134 155 2 132 154 3 (comparative) 94 103 4 (comparative) 472 556 5 (comparative) 63 71

[0188] The 0.6 mm thick plates were tested to determine their disintegration under industrial composting conditions. The test was conducted according to ISO20200:2004 over a period of 91 days. The samples were cut into squares of about 2.5 cm side, mixed with synthetic waste and incubated at 58° C. At the end of the test, the compost mass was sieved and the residues recovered, cleaned as much as possible and weighed. The difference in weight (start-end test) constituted the Disintegration of the sample.

TABLE-US-00003 TABLE 3 Disintegration test Examples Weight loss after 90 days at 58° C. 1 >90% 2 >90% 3(comparative) >90% 4 (comparative) <90%