A process for the preparation of a polybutylene succinate-carbonate

Abstract

The application discloses a preparation method of polybutylene succinate-carbonate, and relates to the technical field of biodegradable materials. The method comprises the following steps: adding dimethyl carbonate, butanediol and catalyst I into a reaction kettle A according to proportions, and obtaining a first mixture by reacting under specific conditions; adding succinic acid, butanediol, catalyst II and a reactive additive into a reaction kettle B according to proportions, and obtaining a second mixture by reacting under specific conditions; mixing the first mixture and the second mixture in the reaction kettle A or B, and reacting under specific conditions; and discharging and cooling after the reaction is completed, so as to obtain polybutylene succinate-carbonate. The method has the advantages of simple process, fast reaction speed and high product yield. The polybutylene succinate-carbonate produced by the method has good water vapor barrier performance and processing performance.

Description

Technical Field

[0001] This invention relates to a method for preparing a copolyester, specifically a method for preparing polybutadiene-succinate-carbonate-butanediol ester. Technical Background

[0002] Polybutylene succinate (PBS) is a research hotspot among biodegradable aliphatic polyesters. It possesses excellent mechanical and heat resistance properties, making it widely used in disposable shopping bags, biomedical polymer materials, packaging bottles, and films. However, PBS's poor water vapor barrier properties limit its applications. Polybutylene carbonate (PBC) has extremely high ester group density, making it a promising candidate for high-barrier packaging. However, its inherent poor heat resistance severely restricts the rapid development of aliphatic polycarbonates.

[0003] Numerous researchers have studied the modification of aliphatic polycarbonates. CN116102720A discloses a poly(terephthalic acid-butanediol carbonate) copolyester and its preparation method, which introduces aromatic monomers into the main chain of the polyester to obtain a PBCT polymer with a high melting point, good molding and processing properties, hydrolysis resistance, and biodegradability. However, the product has low tensile strength, which limits its application range. CN118108933A discloses a high-barrier-performance poly(terephthalic acid-succinic acid-butanediol carbonate) copolyester and its preparation method. First, a nanoscale solid composite catalyst prepared using nano-SiO2 as a carrier is mixed with an amino acid-based ionic liquid to obtain a composite catalyst composition. Then, this composition is mixed with terephthalic acid, succinic acid, dimethyl carbonate, and 1,4-butanediol and subjected to esterification or transesterification, pre-condensation, and final condensation reactions to prepare the PBSCT copolyester. Compared to PBST, PBSCT improves water vapor barrier performance by 1–4 times and oxygen and carbon dioxide barrier performance by 2–14 times, with a yield of 90%. However, the catalyst preparation method used in this process is complex, and the production process suffers from long reaction times, high energy consumption, and poor economic efficiency. Therefore, improving the overall performance of aliphatic polycarbonate modified products, shortening reaction time, and further increasing product yield are urgent technical problems to be solved. Summary of the Invention

[0004] This invention provides a method for preparing polybutylene succinate-carbonate (PBSC). The PBSC produced by this method exhibits excellent water vapor barrier properties and processability. This method has the advantages of simple process, fast reaction rate, and high product yield.

[0005] To achieve the above objectives, the present invention provides a method for preparing polybutanediol carbonate, which adopts the following technical solution: A method for preparing polybutanediol carbonate includes the following steps: Dimethyl carbonate, butanediol and catalyst I were added to reactor A in proportion and reacted at 90-160℃ for 2-3 hours to obtain the first mixture. Succinic acid, butanediol, catalyst II and reactive additives are added to reactor B in proportion and reacted at 140-190℃ for 2-3 hours to obtain a second mixture; The first mixture and the second mixture are mixed in reactor A or B and reacted at 160–190°C for 0.5–2 hours to obtain the third mixture; The third mixture was reacted at 190–230°C and an absolute pressure of 0.15–60 kPa for 0.5–2 h to obtain the fourth mixture; The fourth mixture was reacted at 230–245°C and 0.01–0.15 kPa absolute pressure for 2–4 hours, discharged, and cooled to obtain polysuccinic acid-carbonate-butanediol ester.

[0006] The molar ratio of dimethyl carbonate to butanediol added to reactor A is 1:2 to 3.5. Dimethyl carbonate and butanediol undergo a transesterification reaction in reactor A. By controlling the appropriate ratio of the two, the transesterification effect can be ensured while reducing raw material consumption.

[0007] Catalyst I is an organic base, used in an amount of 0.2% to 1.0% of the mass of dimethyl carbonate. Organic base-catalyzed transesterification has the advantages of mild reaction conditions and high reaction efficiency. By using an appropriate amount of organic base to catalyze the transesterification reaction of dimethyl carbonate and butanediol, high transesterification efficiency can be achieved at lower temperature conditions, reducing the loss of dimethyl carbonate and thus increasing product yield.

[0008] The molar ratio of succinic acid to butanediol added to reactor B is 1:1.1 to 1.5. Succinic acid and butanediol undergo an esterification reaction in reactor B. By controlling the appropriate ratio of the two, the esterification effect can be ensured while reducing the consumption of raw materials.

[0009] The molar ratio of succinic acid to dimethyl carbonate is 1:0.05–0.20. By controlling the ratio of succinic acid to dimethyl carbonate, a specific proportion of aliphatic carbonate segments is introduced into the PBS structure. This significantly improves water vapor barrier properties while maintaining good mechanical and heat resistance properties, ultimately yielding poly(butylene succinate-carbonate) (PBSC) that possesses both the thermal stability of PBS and the barrier properties of PBC.

[0010] Catalyst II is composed of titanate and phosphate ester, and is used in an amount of 0.2% to 0.5% of the mass of succinic acid. Catalyst II can accelerate the esterification reaction of succinic acid and butanediol, and also acts as a polycondensation catalyst to promote the polycondensation reaction.

[0011] The reactive additive is glycerol or trimethylolpropane or a mixture thereof, and is used in an amount of 0.05% to 0.25% of the mass of succinic acid. The addition of an appropriate amount of reactive additive can regulate the molecular structure of polyester and improve product performance.

[0012] The poly(butylene succinate) has a tensile strength ≥40MPa and an elongation at break ≥350%. These excellent mechanical properties allow the poly(butylene succinate) to meet the requirements of a wider range of applications.

[0013] The waste liquid generated during the preparation of poly(butylene succinate-carbonate) is collected and treated after cooling. This cooling and collection process addresses the potential pollution problem caused by the waste liquid during the synthesis of poly(butylene succinate-carbonate).

[0014] The beneficial effects of this invention are as follows: Through research on transesterification processes and catalysts, highly efficient transesterification of dimethyl carbonate and butanediol under mild conditions was achieved. Through research on esterification processes, polycondensation processes, catalysts, and reactive auxiliaries, high-efficiency production of poly(butylene succinate-carbonate) (PBSC) was achieved. By introducing a specific proportion of butanediol carbonate into the PBS structure, PBSC possessing both the thermal stability of PBS and the barrier properties of PBC is obtained. This method has the advantages of simple process, fast reaction rate, and high product yield. The PBSC product produced by this method exhibits good water vapor barrier properties and processability. Detailed Implementation

[0015] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0016] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0017] The present invention will be further described in detail below with reference to specific embodiments. Example

[0018] 1) Weigh 390.00g (4.33mol) of dimethyl carbonate, 1010.00g (11.18mol) of butanediol and 1.00g of catalyst I, add them to reactor A, and react at 90-160℃ for 3h to obtain the first mixture; 2) Weigh 2681.00g (22.61mol) of succinic acid, 2250.03g (24.92mol) of butanediol, 5.25g of catalyst II and 1.31g of glycerol and add them to reactor B. React at 190℃ for 2h to obtain the second mixture; 3) The first mixture and the second mixture are mixed in reactor A and reacted at 190°C for 0.5 h to obtain the third mixture; 4) The third mixture was reacted at 190–230°C and 0.15–60 kPa absolute pressure for 1 hour to obtain the fourth mixture; 5) The fourth mixture was reacted at 230-245℃ and 0.01-0.15kPa absolute pressure for 3.9h, discharged, and cooled to obtain polysuccinic acid-carbonate-butanediol ester. Example

[0019] 1) Weigh 300.00g (3.33mol) of dimethyl carbonate, 660.00g (7.31mol) of butanediol and 1.20g of catalyst I, add them to reactor A, and react at 90-160℃ for 2.8h to obtain the first mixture; 2) Weigh 2228.00g (18.79mol) of succinic acid, 2040.00g (22.59mol) of butanediol, 5.13g of catalyst II and 2.23g of glycerol and add them to reactor B. React at 145℃ for 3.0h to obtain the second mixture; 3) The first mixture and the second mixture are mixed in reactor A and reacted at 190°C for 1 hour to obtain the third mixture; 4) The third mixture was reacted at 190–230°C and 0.15–60 kPa absolute pressure for 1 hour to obtain the fourth mixture; 5) The fourth mixture was reacted at 230-245℃ and 0.01-0.15kPa absolute pressure for 3.8h, discharged, and cooled to obtain polysuccinic acid-carbonate-butanediol ester. Example

[0020] 1) Weigh 200.00g (2.22mol) of dimethyl carbonate, 480.00g (5.32mol) of butanediol and 1.20g of catalyst I, add them to reactor A, and react at 90-160℃ for 2.5h to obtain the first mixture; 2) Weigh 2360.00g (19.91mol) of succinic acid, 2340.00g (25.91mol) of butanediol, 6.14g of catalyst II and 3.54g of trimethylolpropane and add them to reactor B. React at 155℃ for 2h to obtain the second mixture. 3) The first mixture and the second mixture are mixed in reactor A and reacted at 160°C for 2 hours to obtain the third mixture; 4) The third mixture was reacted at 190–230°C and an absolute pressure of 0.15–60 kPa for 0.6 h to obtain the fourth mixture; 5) The fourth mixture was reacted at 230-245℃ and 0.01-0.15kPa absolute pressure for 3.6h, discharged, and cooled to obtain polysuccinic acid-carbonate-butanediol ester. Example

[0021] 1) Weigh 100.00g (1.11mol) of dimethyl carbonate, 260.00g (2.88mol) of butanediol and 0.80g of catalyst I, add them to reactor A, and react at 90-160℃ for 2.2h to obtain the first mixture; 2) Weigh 2490.00g (21.00mol) of succinic acid, 2660.00g (29.46mol) of butanediol, 7.22g of catalyst II and 4.98g of trimethylolpropane and add them to reactor B. React at 155℃ for 2.5h to obtain the second mixture. 3) The first mixture and the second mixture are mixed in reactor A and reacted at 185°C for 1 hour to obtain the third mixture; 4) The third mixture was reacted at 190–230°C and an absolute pressure of 0.15–60 kPa for 0.5 h to obtain the fourth mixture; 5) The fourth mixture was reacted at 230-245℃ and 0.01-0.15kPa absolute pressure for 3.2h, discharged, and cooled to obtain polysuccinic acid-carbonate-butanediol ester. Example

[0022] 1) Weigh 360.00g (4.00mol) of dimethyl carbonate, 1200.00g (13.29mol) of butanediol and 5.00g of catalyst I, add them to reactor A, and react at 90-160℃ for 2.0h to obtain the first mixture; 2) Weigh 2900.00g (24.46mol) of succinic acid, 3000.00g (33.22mol) of butanediol, 8.39g of catalyst II and 6.55g of glycerol and add them to reactor B. React at 175℃ for 2h to obtain the second mixture; 3) The first mixture and the second mixture are mixed in reactor A and reacted at 180°C for 1.5 h to obtain the third mixture; 4) The third mixture was reacted at 190–230°C and an absolute pressure of 0.15–60 kPa for 0.5 h to obtain the fourth mixture; 5) The fourth mixture was reacted at 230-245℃ and 0.01-0.15kPa absolute pressure for 2.8h, discharged, and cooled to obtain polysuccinic acid-carbonate-butanediol ester. Example

[0023] 1) Weigh 300.00g (3.33mol) of dimethyl carbonate, 900.00g (9.97mol) of butanediol and 3.00g of catalyst I, add them to reactor A, and react at 90-160℃ for 2.1h to obtain the first mixture; 2) Weigh 2230.00g (18.81mol) of succinic acid, 1870.00g (20.71mol) of butanediol, 7.80g of catalyst II and 1.11g of trimethylolpropane and add them to reactor B. React at 165℃ for 2.5h to obtain the second mixture. 3) The first mixture and the second mixture are mixed in reactor B and reacted at 160°C for 2 hours to obtain the third mixture; 4) The third mixture was reacted at 190–230°C and an absolute pressure of 0.15–60 kPa for 1.5 h to obtain the fourth mixture; 5) The fourth mixture was reacted at 230-245℃ and 0.01-0.15kPa absolute pressure for 3.3h, discharged, and cooled to obtain polysuccinic acid-carbonate-butanediol ester. Example

[0024] 1) Weigh 200.00g (2.22mol) of dimethyl carbonate, 700.00g (7.75mol) of butanediol and 1.20g of catalyst I, add them to reactor A, and react at 90-160℃ for 2.7h to obtain the first mixture; 2) Weigh 2360.00g (19.91mol) of succinic acid, 2160.00g (23.92mol) of butanediol, 8.97g of catalyst II, 1.20g of glycerol and 1.16g of trimethylolpropane and add them to reactor B. React at 160℃ for 2.5h to obtain the second mixture. 3) The first mixture and the second mixture are mixed in reactor B and reacted at 170°C for 2 hours to obtain the third mixture; 4) The third mixture was reacted at 190–230°C and 0.15–60 kPa absolute pressure for 2 hours to obtain the fourth mixture; 5) The fourth mixture was reacted at 230-245℃ and 0.01-0.15kPa absolute pressure for 3.1h, discharged, and cooled to obtain polysuccinic acid-carbonate-butanediol ester. Example

[0025] 1) Weigh 100.00g (1.11mol) of dimethyl carbonate, 330.00g (3.65mol) of butanediol and 0.80g of catalyst I, add them to reactor A, and react at 90-160℃ for 2.5h to obtain the first mixture; 2) Weigh 2490.00g (21.00mol) of succinic acid, 2470.00g (27.35mol) of butanediol, 10.46g of catalyst II, 2.20g of glycerol and 1.54g of trimethylolpropane and add them to reactor B. React at 160℃ for 2.7h to obtain the second mixture. 3) The first mixture and the second mixture are mixed in reactor B and reacted at 170°C for 2 hours to obtain the third mixture; 4) The third mixture was reacted at 190–230°C and an absolute pressure of 0.15–60 kPa for 0.8 h to obtain the fourth mixture; 5) The fourth mixture was reacted at 230-245℃ and 0.01-0.15kPa absolute pressure for 2.8h, discharged, and cooled to obtain polysuccinic acid-carbonate-butanediol ester. Example

[0026] 1) Weigh 370.00g (4.11mol) of dimethyl carbonate, 1200.00g (13.29mol) of butanediol and 1.00g of catalyst I, add them to reactor A, and react at 90-160℃ for 2.9h to obtain the first mixture; 2) Weigh 2800.00g (23.62mol) of succinic acid, 2800.00g (31.01mol) of butanediol, 11.80g of catalyst II, 1.20g of glycerol and 1.60g of trimethylolpropane and add them to reactor B. React at 185℃ for 2.5h to obtain the second mixture; 3) The first mixture and the second mixture are mixed in reactor B and reacted at 190°C for 1 hour to obtain the third mixture; 4) The third mixture was reacted at 190–230°C and 0.15–60 kPa absolute pressure for 1 hour to obtain the fourth mixture; 5) The fourth mixture was reacted at 230-245℃ and 0.01-0.15kPa absolute pressure for 2.4h, discharged, and cooled to obtain polysuccinic acid-carbonate-butanediol ester. Example

[0027] 1) Weigh 300.00g (3.33mol) of dimethyl carbonate, 780.00g (8.64mol) of butanediol and 1.20g of catalyst I, add them to reactor A, and react at 90-160℃ for 2.6h to obtain the first mixture; 2) Weigh 2230.00g (18.81mol) of succinic acid, 2540.00g (28.13mol) of butanediol, 10.70g of catalyst II, 2.50g of trimethylolpropane, 3.07g of pentaerythritol and 4.72g of antioxidant and add them to reactor B. React at 180℃ for 3h to obtain the second mixture. 3) The first mixture and the second mixture are mixed in reactor B and reacted at 190°C for 1 hour to obtain the third mixture; 4) The third mixture was reacted at 190–230°C and an absolute pressure of 0.15–60 kPa for 1.2 h to obtain the fourth mixture; 5) The fourth mixture was reacted at 230-245℃ and 0.01-0.15kPa absolute pressure for 2.1h, discharged, and cooled to obtain polysuccinic acid-carbonate-butanediol ester.

[0028] The comparative example is polybutylene succinate (PBS).

[0029] Comparative Example 1 1) Weigh 3000.00g of succinic acid, 2976.33g of butanediol, 9.60g of catalyst II and 3.00g of trimethylolpropane and add them to the reaction vessel. React at 160-190℃ for 3h to obtain the first mixture; 2) The first mixture was reacted at 190–230°C and an absolute pressure of 0.15–60 kPa for 1.2 h to obtain the second mixture; 3) The second mixture was reacted at 230-245℃ and 0.01-0.15kPa absolute pressure for 3.3h, discharged, and cooled to obtain polybutylene succinate.

[0030] Comparative Example 2 1) Weigh 3000.00g of succinic acid, 2976.33g of butanediol, 9.60g of catalyst II and 4.50g of trimethylolpropane and add them to the reaction vessel. React at 160-190℃ for 3h to obtain the first mixture; 2) The first mixture was reacted at 190–230°C and an absolute pressure of 0.15–60 kPa for 1.2 h to obtain the second mixture; 3) The second mixture was reacted at 230-245℃ and 0.01-0.15kPa absolute pressure for 3.0h, discharged, and cooled to obtain polybutylene succinate.

[0031] The samples prepared in the above examples and comparative examples were subjected to mechanical property testing according to GB / T1040.2-2018 "Determination of Tensile Properties of Plastics"; the films prepared in the above examples and comparative examples were subjected to water vapor transmission rate (WVT) testing. Specific test results are as follows: Example 1 43.23 528.26 243.25 92.65 Example 2 46.46 459.73 256.31 92.78 Example 3 55.34 388.61 282.48 93.51 Example 4 45.13 368.27 310.03 94.76 Example 5 41.35 423.54 234.12 95.13 Example 6 49.43 498.67 241.62 95.21 Example 7 54.79 423.23 274.81 95.34 Example 8 42.08 383.61 285.34 94.79 Example 9 41.29 455.79 226.12 93.46 Example 10 43.85 410.51 229.53 94.47 Comparative Example 1 35.71 278.96 499.62 / Comparative Example 2 37.24 243.15 483.21 / The foregoing has shown and described the main features and advantages of the present invention. Compared with the comparative examples, the polybutanediol succinate product prepared using the processes and formulations of the embodiments exhibits good water vapor barrier properties and processing performance. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description, and therefore all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the invention. The claims should not be construed as limiting the scope of the claims.

[0032] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution; this narrative style is merely for clarity. Those skilled in the art should consider this specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A method for preparing polybutanediol carbonate, characterized in that, Includes the following steps: 1) Add dimethyl carbonate, butanediol and catalyst I to reactor A in proportion, and react at 90-160℃ for 2-3 hours to obtain the first mixture; 2) Add succinic acid, butanediol, catalyst II and reactive additives to reactor B in proportion, and react at 140-190℃ for 2-3 hours to obtain the second mixture; 3) Mix the first mixture with the second mixture in reactor A or B, and react at 160–190°C for 0.5–2 hours to obtain the third mixture; 4) The third mixture is reacted at 190–230°C and 0.15–60 kPa absolute pressure for 0.5–2 h to obtain the fourth mixture; 5) The fourth mixture was reacted at 230-245℃ and 0.01-0.15kPa absolute pressure for 2-4 hours, then discharged and cooled to obtain polysuccinic acid-carbonate-butanediol ester.

2. The method for preparing polysuccinic acid-butanediol carbonate according to claim 1, characterized in that, The molar ratio of dimethyl carbonate to butanediol added to reactor A is 1:2 to 3.

5.

3. The method for preparing polysuccinic acid-butanediol carbonate according to claim 1, characterized in that, Catalyst I is an organic base, and its dosage is 0.2% to 1.0% of the mass of dimethyl carbonate.

4. The method for preparing polysuccinic acid-butanediol carbonate according to claim 1, characterized in that, The molar ratio of succinic acid to butanediol added to reactor B is 1:1.1 to 1.

5.

5. The method for preparing polysuccinic acid-butanediol carbonate according to claim 1, characterized in that, The molar ratio of succinic acid to dimethyl carbonate is 1:0.05 to 0.

20.

6. The method for preparing polysuccinic acid-butanediol carbonate according to claim 1, characterized in that, Catalyst II is composed of titanate and phosphate ester, and is used in an amount of 0.2% to 0.5% of the mass of succinic acid.

7. The method for preparing polysuccinic acid-butanediol carbonate according to claim 1, characterized in that, The reactive auxiliary is one of glycerol or trimethylolpropane or a mixture thereof, and is used in an amount of 0.05% to 0.25% of the mass of succinic acid.

8. The method for preparing polybutylene succinate according to any one of claims 1-7, characterized in that, The polysuccinic acid-butanediol carbonate has a tensile strength ≥40MPa and an elongation at break ≥350%.

9. The method for preparing polybutane-succinic acid-butanediol carbonate according to any one of claims 1-7, characterized in that, The waste liquid generated during the preparation of polysuccinic acid-butanediol carbonate is collected and treated after cooling.