A biodegradable synthetic resin and a method for preparing the same

Abstract

The application discloses a kind of biodegradable synthetic resin and preparation method thereof, the biodegradable synthetic resin includes the following weight parts raw materials: hydroxyl-terminated biodegradable polyester elastomer 10-30 parts, modified polybutylene succinate 60-80 parts, polyglycolide resin 15-30 parts, compatibility agent 5-10 parts, antioxidant 0.1-1 part and lubricant 0.1-1 part.The raw materials of biodegradable synthetic resin used in the application are all full biodegradable materials, not only widely available, but also can complete biodegradation, it is an environment-friendly synthetic resin;The biodegradable synthetic resin of the application has good mechanical comprehensive performance and high thermal decomposition temperature.

Description

Technical Field

[0001] This invention relates to the field of synthetic resin technology, and specifically to a biodegradable synthetic resin and its preparation method. Background Technology

[0002] Synthetic resins are a class of artificially synthesized polymer compounds, typically basic materials produced by the polymerization reaction of monomers. Sometimes, the term also refers to uncured, free-flowing thermosetting polymer materials. Synthetic resins possess numerous advantages, such as high mechanical strength, high temperature resistance, corrosion resistance, and good insulation properties, and are widely used in various fields, including packaging, construction, electronics, and automobiles.

[0003] With advancements in technology and improved living standards, plastics made from synthetic resins are used in all aspects of life. However, the manufacture of synthetic resins requires large quantities of fossil raw materials, resulting in high production costs, and these raw materials are typically derived from non-renewable resources. Furthermore, synthetic resins have poor biodegradability; most cannot be naturally broken down, causing long-term environmental pollution. To address these drawbacks of synthetic resins, researchers are actively exploring new materials and technologies to reduce their environmental impact and harm. For example, the development of biodegradable synthetic resins is one such approach. Biodegradable synthetic resins can be broken down into harmless substances through the action of microorganisms, and their production costs are relatively low, thus reducing environmental pollution and harm.

[0004] However, the physical and chemical properties of existing biodegradable synthetic resins are inferior to those of traditional plastics, generally exhibiting poor physical strength and heat resistance. In some demanding applications, these performance issues become limiting factors. Furthermore, to achieve effective biodegradation of synthetic resins, specific environmental conditions are usually required. Some synthetic resins, after degradation, produce microplastic particles, which still pose a threat to ecosystems and wildlife. Summary of the Invention

[0005] Based on the problems existing in the background technology, the present invention provides a biodegradable synthetic resin and its preparation method. The synthetic resin of the present invention can be completely degraded and has good comprehensive mechanical properties and a high thermal decomposition temperature.

[0006] The first aspect of the present invention provides a biodegradable synthetic resin comprising the following raw materials in parts by weight: 10-30 parts of hydroxyl-terminated biodegradable polyester elastomer, 60-80 parts of modified polybutylene succinate, 15-30 parts of polyglycolic acid resin, 5-10 parts of compatibilizer, 0.1-1 parts of antioxidant and 0.1-1 parts of lubricant;

[0007] The hydroxyl-terminated biodegradable polyester elastomer was prepared from dimethyl terephthalate, 1,4-butanediol, ethylene glycol and adipic acid.

[0008] The modified polybutylene succinate was prepared from succinic anhydride, p-toluenesulfonic acid, 1,4-butanediol and 1,3-propanediol.

[0009] Further, the specific preparation method of hydroxyl-terminated biodegradable polyester elastomer is as follows: Dimethyl terephthalate, 1,4-butanediol, ethylene glycol and tetrabutyl titanate are added to a stirrer and heated to 150-180℃ under nitrogen protection to carry out transesterification reaction. After 90% of the distillate produced during the reaction is distilled off, adipic acid is added, and the temperature is raised to 180-220℃ to carry out transesterification reaction. After all the distillate produced during the reaction is distilled off, the vacuum is drawn to 500Pa and the temperature is raised to 230-270℃. After reacting for 30 minutes, the vacuum is further drawn to below 100Pa and maintained for 4-6 hours. After the reaction is completed, the temperature is lowered to room temperature to obtain hydroxyl-terminated biodegradable polyester elastomer.

[0010] The molar ratio of dimethyl terephthalate, 1,4-butanediol, ethylene glycol, adipic acid and tetrabutyl titanate is (50-60):(70-90):(15-25):(40-50):2.

[0011] Further, the preparation method of modified polybutylene succinate is as follows: succinic anhydride and p-toluenesulfonic acid are added to a reaction vessel, purged with argon, heated to 130-160℃, 1,4-butanediol and 1,3-propanediol are added, the reaction is continued for 30 min, the temperature is raised to 180-200℃, the reaction is carried out for 3-4 h, and then cooled to room temperature to obtain product A. Product A is transferred to a vacuum distillation apparatus, purged with argon, a catalyst is added and stirred evenly, and a polycondensation reaction is carried out under vacuum for 1-1.5 h. After the reaction is completed, chloroform is added to dissolve the product, anhydrous methanol is added, the precipitate is rapidly stirred to precipitate, filtered, and dried to obtain modified polybutylene succinate.

[0012] The weight ratio of succinic anhydride, toluenesulfonic acid, 1,4-butanediol and 1,3-propanediol is (90-100):(0.15-0.2):(90-110):(15-25).

[0013] The amount of catalyst used is 0.05-0.5% of the weight of product A.

[0014] Furthermore, the molecular weight of polyglycolic acid resin is 50,000-150,000.

[0015] Furthermore, the compatibilizer is one or more of the following: styrene-acrylonitrile-maleic anhydride copolymer, ethylene-acrylate-glycidyl ester copolymer, ethylene-glycidyl ester, or ethylene-n-butyl acrylate-glycidyl ester copolymer.

[0016] Furthermore, the antioxidant is one of hindered phenolic antioxidants or phosphite antioxidants.

[0017] Furthermore, the lubricant is one or more of calcium stearate, magnesium stearate, zinc stearate, PE wax, or PP wax.

[0018] A second aspect of the present invention also provides a method for preparing a biodegradable synthetic resin, comprising the following steps:

[0019] S1. Take hydroxyl-terminated biodegradable polyester elastomer, modified polybutylene succinate, polyglycolic acid resin, compatibilizer, antioxidant and lubricant, mix them evenly, and then dry them.

[0020] S2. After drying, the mixture is fed into a twin-screw extruder for melt blending and extrusion. The extruded material is cooled to room temperature and then pelletized by a pelletizer to obtain the biodegradable synthetic resin.

[0021] Furthermore, in step S1, the mixing is carried out by using a high-speed mixer at a stirring speed of 500-700 r / min for 20-30 min.

[0022] Furthermore, in step S2, the extrusion temperature of the twin-screw extruder is 200-220℃, the die temperature is 180-200℃, and the screw speed is 60-80 r / min.

[0023] The beneficial effects of this invention are:

[0024] The present invention provides a biodegradable synthetic resin based on modified polybutylene succinate, combined with the synergistic effect of hydroxyl-terminated biodegradable polyester elastomer and polyglycolic acid resin and other additives, resulting in a synthetic resin with good comprehensive mechanical properties. By using hydroxyl-terminated biodegradable polyester elastomer and modified polybutylene succinate, the thermal decomposition temperature of the synthetic resin is significantly improved, expanding the application prospects of the synthetic resin.

[0025] The biodegradable synthetic resin of this invention uses fully biodegradable materials as raw materials, which are not only widely available but also capable of complete biodegradation, making it an environmentally friendly synthetic resin. The modified polybutylene succinate only degrades under conditions of contact with microorganisms, such as composting, and its performance is very stable during normal storage and use. Detailed Implementation

[0026] The technical solution of the present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0027] The types of raw materials used in the embodiments and comparative examples of this invention are as follows:

[0028] Dimethyl terephthalate was purchased from Jiangsu Runfeng Synthetic Technology Co., Ltd.

[0029] 1,4-Butanediol, 1,3-Propanediol, and ethylene glycol are all from Sinopharm Chemical Co., Ltd.

[0030] Adipic acid was purchased from Nantong Runfeng Petrochemical Co., Ltd.

[0031] Tetrabutyl titanate was purchased from BASF Tianjin Co., Ltd.

[0032] Succinic anhydride was purchased from Jiangsu Pulesi Biotechnology Co., Ltd.

[0033] p-Toluenesulfonic acid was purchased from Shandong Yukang Chemical Co., Ltd.

[0034] Polyglycolic acid with a molecular weight of 100,000 was purchased from Wuhan Shuer Biotechnology Co., Ltd.

[0035] The compatibilizer is a styrene-acrylonitrile-maleic anhydride copolymer;

[0036] The antioxidant is BASF IRGANOX 1330;

[0037] The lubricant is calcium stearate.

[0038] Example 1

[0039] A biodegradable synthetic resin, the preparation method of which includes the following steps:

[0040] (1) Preparation of hydroxyl-terminated biodegradable polyester elastomer: Dimethyl terephthalate, 1,4-butanediol, ethylene glycol and tetrabutyl titanate were added to a stirrer and heated to 150-180℃ under nitrogen protection to carry out transesterification reaction. After 90% of the distillate produced during the reaction was distilled off, adipic acid was added and the temperature was raised to 200℃ to carry out transesterification reaction. After all the distillate produced during the reaction was distilled off, the vacuum was drawn to 500Pa and the temperature was raised to 250℃. After reacting for 30 minutes, the vacuum was further drawn to below 100Pa and maintained for 5 hours. After the reaction was completed, the temperature was lowered to room temperature to obtain hydroxyl-terminated biodegradable polyester elastomer.

[0041] In this step, the molar ratio of dimethyl terephthalate, 1,4-butanediol, ethylene glycol, adipic acid, and tetrabutyl titanate is 55:80:20:45:2.

[0042] (2) Preparation of modified polybutylene succinate: Succinic anhydride and p-toluenesulfonic acid were added to the reaction vessel, purged with argon, heated to 150°C, 1,4-butanediol and 1,3-propanediol were added, and the reaction was continued for 30 min. The temperature was raised to 200°C and the reaction was carried out for 4 h. The temperature was then lowered to room temperature to obtain product A. Product A was transferred to a vacuum distillation apparatus, purged with argon, tetrabutyl titanate was added and stirred evenly, and polycondensation reaction was carried out under vacuum for 1.5 h. After the reaction was completed, chloroform was added to dissolve the product, anhydrous methanol was added, and the precipitate was precipitated by rapid stirring. The precipitate was filtered and dried to obtain modified polybutylene succinate.

[0043] In this step, the weight ratio of succinic anhydride, toluenesulfonic acid, 1,4-butanediol, and 1,3-propanediol is 90:0.15:100:20; the amount of tetrabutyl titanate used is 0.3% of the weight of product A.

[0044] (3) Take 20 parts of hydroxyl-terminated biodegradable polyester elastomer, 70 parts of modified polybutylene succinate, 15 parts of polyglycolic acid resin, 8 parts of compatibilizer, 0.5 parts of antioxidant and 0.5 parts of lubricant, mix them in a high-speed mixer at a stirring speed of 600 r / min for 25 min, and then dry them. After drying, the mixture is fed into a twin-screw extruder for melt blending and extrusion. The extrusion temperature is 220℃, the die temperature is 200℃ and the screw speed is 80 r / min. The extruded material is pelletized by a pelletizer to obtain biodegradable synthetic resin.

[0045] Example 2

[0046] A biodegradable synthetic resin, the preparation method of which includes the following steps:

[0047] Steps (1) and (2) are the same as in Example 1;

[0048] (3) Take 30 parts of hydroxyl-terminated biodegradable polyester elastomer, 70 parts of modified polybutylene succinate, 15 parts of polyglycolic acid resin, 8 parts of compatibilizer, 0.5 parts of antioxidant and 0.5 parts of lubricant, mix them in a high-speed mixer at a stirring speed of 600 r / min for 25 min, and then dry them. After drying, the mixture is fed into a twin-screw extruder for melt blending and extrusion. The extrusion temperature is 220℃, the die temperature is 200℃ and the screw speed is 80 r / min. The extruded material is pelletized by a pelletizer to obtain biodegradable synthetic resin.

[0049] Example 3

[0050] A biodegradable synthetic resin, the preparation method of which includes the following steps:

[0051] Steps (1) and (2) are the same as in Example 1;

[0052] (3) Take 20 parts of hydroxyl-terminated biodegradable polyester elastomer, 80 parts of modified polybutylene succinate, 15 parts of polyglycolic acid resin, 8 parts of compatibilizer, 0.5 parts of antioxidant and 0.5 parts of lubricant, mix them in a high-speed mixer at a stirring speed of 600 r / min for 25 min, and then dry them. After drying, the mixture is fed into a twin-screw extruder for melt blending and extrusion. The extrusion temperature is 220℃, the die temperature is 200℃ and the screw speed is 80 r / min. The extruded material is pelletized by a pelletizer to obtain biodegradable synthetic resin.

[0053] Example 4

[0054] A biodegradable synthetic resin, the preparation method of which includes the following steps:

[0055] Steps (1) and (2) are the same as in Example 1;

[0056] (3) Take 20 parts of hydroxyl-terminated biodegradable polyester elastomer, 70 parts of modified polybutylene succinate, 25 parts of polyglycolic acid resin, 8 parts of compatibilizer, 0.5 parts of antioxidant and 0.5 parts of lubricant, and mix them in a high-speed mixer at a stirring speed of 600 r / min for 25 min, and then dry them. After drying, the mixture is fed into a twin-screw extruder for melt blending and extrusion. The extrusion temperature is 220℃, the die temperature is 200℃ and the screw speed is 80 r / min. The extruded material is pelletized by a pelletizer to obtain biodegradable synthetic resin.

[0057] Comparative Example 1

[0058] A biodegradable synthetic resin is prepared by the following method: 20 parts of PBAT, 70 parts of polybutylene succinate, 15 parts of polyethylene glycol resin, 8 parts of compatibilizer, 0.5 parts of antioxidant, and 0.5 parts of lubricant are mixed in a high-speed mixer at a stirring speed of 600 r / min for 25 min, and then dried. After drying, the mixture is fed into a twin-screw extruder for melt blending and extrusion. The extrusion temperature is 220℃, the die temperature is 200℃, and the screw speed is 80 r / min. The extruded material is pelletized by a pelletizer to obtain the biodegradable synthetic resin.

[0059] Comparative Example 2

[0060] A biodegradable synthetic resin, the preparation method of which includes the following steps:

[0061] (1) Preparation of hydroxyl-terminated biodegradable polyester elastomer: Dimethyl terephthalate, 1,4-butanediol, ethylene glycol and tetrabutyl titanate were added to a stirrer and heated to 150-180℃ under nitrogen protection to carry out transesterification reaction. After 90% of the distillate produced during the reaction was distilled off, adipic acid was added and the temperature was raised to 200℃ to carry out transesterification reaction. After all the distillate produced during the reaction was distilled off, the vacuum was drawn to 500Pa and the temperature was raised to 250℃. After reacting for 30 minutes, the vacuum was further drawn to below 100Pa and maintained for 5 hours. After the reaction was completed, the temperature was lowered to room temperature to obtain hydroxyl-terminated biodegradable polyester elastomer.

[0062] In this step, the molar ratio of dimethyl terephthalate, 1,4-butanediol, ethylene glycol, adipic acid, and tetrabutyl titanate is 55:80:20:45:2.

[0063] (2) Take 20 parts of hydroxyl-terminated biodegradable polyester elastomer, 70 parts of polybutylene succinate, 15 parts of polyglycolic acid resin, 8 parts of compatibilizer, 0.5 parts of antioxidant and 0.5 parts of lubricant, mix them in a high-speed mixer at a stirring speed of 600 r / min for 25 min, and then dry them. After drying, the mixture is fed into a twin-screw extruder for melt blending and extrusion. The extrusion temperature is 220℃, the die temperature is 200℃ and the screw speed is 80 r / min. The extruded material is pelletized by a pelletizer to obtain biodegradable synthetic resin.

[0064] Comparative Example 3

[0065] A biodegradable synthetic resin, the preparation method of which includes the following steps:

[0066] (1) Preparation of modified polybutylene succinate: Succinic anhydride and p-toluenesulfonic acid were added to the reaction vessel, purged with argon, heated to 150°C, 1,4-butanediol and 1,3-propanediol were added, and the reaction was continued for 30 min. The temperature was raised to 200°C and the reaction was carried out for 4 h. The temperature was then lowered to room temperature to obtain product A. Product A was transferred to a vacuum distillation apparatus, purged with argon, tetrabutyl titanate was added and stirred evenly, and polycondensation reaction was carried out under vacuum for 1.5 h. After the reaction was completed, chloroform was added to dissolve the product, anhydrous methanol was added, and the precipitate was precipitated by rapid stirring. The precipitate was filtered and dried to obtain modified polybutylene succinate.

[0067] In this step, the weight ratio of succinic anhydride, toluenesulfonic acid, 1,4-butanediol, and 1,3-propanediol is 90:0.15:100:20; the amount of tetrabutyl titanate used is 0.3% of the weight of product A.

[0068] (2) Take 20 parts of PBAT, 70 parts of modified polybutylene succinate, 15 parts of polyglycolic acid resin, 8 parts of compatibilizer, 0.5 parts of antioxidant and 0.5 parts of lubricant, mix them in a high-speed mixer at a stirring speed of 600 r / min for 25 min, and then dry them. After drying, the mixture is fed into a twin-screw extruder for melt blending and extrusion. The extrusion temperature is 220℃, the die temperature is 200℃ and the screw speed is 80 r / min. The extruded material is pelletized by a pelletizer to obtain biodegradable synthetic resin.

[0069] Comparative Example 4

[0070] A biodegradable synthetic resin, the preparation method of which includes the following steps:

[0071] Steps (1) and (2) are the same as in Example 1;

[0072] (3) Take 20 parts of hydroxyl-terminated biodegradable polyester elastomer, 70 parts of modified polybutylene succinate, 8 parts of compatibilizer, 0.5 parts of antioxidant and 0.5 parts of lubricant, mix them in a high-speed mixer at a stirring speed of 600 r / min for 25 min, and then dry them. After drying, the mixture is fed into a twin-screw extruder for melt blending and extrusion. The extrusion temperature is 220℃, the die temperature is 200℃ and the screw speed is 80 r / min. The extruded material is pelletized by a pelletizer to obtain biodegradable synthetic resin.

[0073] Comparative Example 5

[0074] A biodegradable synthetic resin, the preparation method of which includes the following steps:

[0075] (1) Preparation of modified polybutylene succinate: Succinic anhydride and p-toluenesulfonic acid were added to the reaction vessel, purged with argon, heated to 150°C, 1,4-butanediol and 1,3-propanediol were added, and the reaction was continued for 30 min. The temperature was raised to 200°C and the reaction was carried out for 4 h. The temperature was then lowered to room temperature to obtain product A. Product A was transferred to a vacuum distillation apparatus, purged with argon, tetrabutyl titanate was added and stirred evenly, and polycondensation reaction was carried out under vacuum for 1.5 h. After the reaction was completed, chloroform was added to dissolve the product, anhydrous methanol was added, and the precipitate was precipitated by rapid stirring. The precipitate was filtered and dried to obtain modified polybutylene succinate.

[0076] In this step, the weight ratio of succinic anhydride, toluenesulfonic acid, 1,4-butanediol, and 1,3-propanediol is 90:0.15:100:20; the amount of tetrabutyl titanate used is 0.3% of the weight of product A.

[0077] (2) Take 70 parts of modified polybutylene succinate, 15 parts of polyglycolic acid resin, 8 parts of compatibilizer, 0.5 parts of antioxidant and 0.5 parts of lubricant, mix them in a high-speed mixer at a stirring speed of 600 r / min for 25 min, and then dry them. After drying, the mixture is fed into a twin-screw extruder for melt blending and extrusion. The extrusion temperature is 220℃, the die temperature is 200℃ and the screw speed is 80 r / min. The extruded material is pelletized by a pelletizer to obtain biodegradable synthetic resin.

[0078] Comparative Example 6

[0079] A biodegradable synthetic resin, the preparation method of which includes the following steps:

[0080] (1) Preparation of hydroxyl-terminated biodegradable polyester elastomer: Dimethyl terephthalate, 1,4-butanediol, ethylene glycol and tetrabutyl titanate were added to a stirrer and heated to 150-180℃ under nitrogen protection to carry out transesterification reaction. After 90% of the distillate produced during the reaction was distilled off, adipic acid was added and the temperature was raised to 200℃ to carry out transesterification reaction. After all the distillate produced during the reaction was distilled off, the vacuum was drawn to 500Pa and the temperature was raised to 250℃. After reacting for 30 minutes, the vacuum was further drawn to below 100Pa and maintained for 5 hours. After the reaction was completed, the temperature was lowered to room temperature to obtain hydroxyl-terminated biodegradable polyester elastomer.

[0081] In this step, the molar ratio of dimethyl terephthalate, 1,4-butanediol, ethylene glycol, adipic acid, and tetrabutyl titanate is 45:80:20:55:2.

[0082] The remaining steps are the same as in Example 1.

[0083] Comparative Example 7

[0084] A biodegradable synthetic resin, the preparation method of which includes the following steps:

[0085] (1) Preparation of hydroxyl-terminated biodegradable polyester elastomer: Same as in Example 1;

[0086] (2) Preparation of modified polybutylene succinate: Succinic anhydride and p-toluenesulfonic acid were added to the reaction vessel, purged with argon, heated to 150°C, 1,4-butanediol and 1,3-propanediol were added, and the reaction was continued for 30 min. The temperature was raised to 200°C and the reaction was carried out for 4 h. The temperature was then lowered to room temperature to obtain product A. Product A was transferred to a vacuum distillation apparatus, purged with argon, tetrabutyl titanate was added and stirred evenly, and polycondensation reaction was carried out under vacuum for 1.5 h. After the reaction was completed, chloroform was added to dissolve the product, anhydrous methanol was added, and the precipitate was precipitated by rapid stirring. The precipitate was filtered and dried to obtain modified polybutylene succinate.

[0087] In this step, the weight ratio of succinic anhydride, toluenesulfonic acid, 1,4-butanediol, and 1,3-propanediol is 90:0.15:100:10; the amount of tetrabutyl titanate used is 0.3% of the weight of product A.

[0088] The remaining steps are the same as in Example 1.

[0089] Comparative Example 8

[0090] A biodegradable synthetic resin, the preparation method of which includes the following steps:

[0091] (1) Preparation of hydroxyl-terminated biodegradable polyester elastomer: Same as in Example 1;

[0092] (2) Preparation of modified polybutylene succinate: Succinic anhydride and p-toluenesulfonic acid were added to the reaction vessel, purged with argon, heated to 150°C, 1,4-butanediol and 1,3-propanediol were added, and the reaction was continued for 30 min. The temperature was raised to 200°C and the reaction was carried out for 4 h. The temperature was then lowered to room temperature to obtain product A. Product A was transferred to a vacuum distillation apparatus, purged with argon, tetrabutyl titanate was added and stirred evenly, and polycondensation reaction was carried out under vacuum for 1.5 h. After the reaction was completed, chloroform was added to dissolve the product, anhydrous methanol was added, and the precipitate was precipitated by rapid stirring. The precipitate was filtered and dried to obtain modified polybutylene succinate.

[0093] In this step, the weight ratio of succinic anhydride, toluenesulfonic acid, 1,4-butanediol, and 1,3-propanediol is 90:0.15:100:30; the amount of tetrabutyl titanate used is 0.3% of the weight of product A.

[0094] The remaining steps are the same as in Example 1.

[0095] Experimental Example 1

[0096] Mechanical property testing: The synthetic resins prepared in Examples 1-4 and Comparative Examples 1-5 were molded into dumbbell-shaped specimens with a diameter of 40 mm, a width of 4 mm, and a thickness of 1 mm using a flat vulcanizing apparatus. The tensile strength and elongation at break of the specimens were tested according to the national standard GB / T 528-2009, with the instrument's tensile rate set to 5 mm / min.

[0097] Impact test: The impact energy of the test samples was tested in accordance with the national standard GB / T1843-2008. The samples in this experiment were all prepared into rectangular strips of 80mm×10mm×4mm with a notch depth of 2mm. The test temperature was 25℃.

[0098] Thermal stability test: Thermogravimetric analysis (TGA) was performed using an HCT-1 (Beijing Hengwen, China) thermogravimetric analyzer at a heating rate of 10℃ / min, from room temperature to 800℃, under N2 atmosphere.

[0099] The test results are shown in Table 1.

[0100] Table 1

[0101] Group Tensile strength (MPa) Elongation at break % <![CDATA[Impact strength kJ / m 2 > Thermal decomposition temperature (°C) Example 1 58 465 13.7 430 Example 2 50 524 15.9 425 Example 3 56 429 12.5 435 Example 4 62 382 11.8 410 Comparative Example 1 45 328 9.6 360 Comparative Example 2 56 414 10.7 375 Comparative Example 3 52 457 8.5 390 Comparative Example 4 31 560 16.8 435 Comparative Example 5 69 157 5.3 405 Comparative Example 6 46 337 10.2 395 Comparative Example 7 50 425 12.4 400 Comparative Example 8 40 334 8.9 440

[0102] As shown in Table 1, the specimens prepared in Examples 1-4 exhibited excellent overall mechanical properties and high thermal decomposition temperatures. In Comparative Example 1, the synthetic resin prepared using PBAT and unmodified polybutylene succinate showed a decrease in overall mechanical properties, with a thermal decomposition temperature of only 360℃. In Comparative Example 2, using unmodified polybutylene succinate, and in Comparative Example 3, using PBAT, the tensile strength and elongation at break of the specimens did not change significantly, but the impact strength and thermal decomposition temperature were significantly lower than in the comparative examples. In Comparative Example 4, without the addition of polyglycolic acid, the tensile strength of the sample was significantly reduced. In Comparative Example 5, without the addition of hydroxyl-terminated biodegradable polyester elastomer, the elongation at break and impact strength of the sample were significantly reduced. In Comparative Example 6, the amounts of dimethyl terephthalate and adipic acid in the hydroxyl-terminated biodegradable polyester elastomer were adjusted. It was found that when the amount of adipic acid increased, the mechanical properties of the specimen decreased, and the thermal decomposition temperature was also significantly lower than in Example 1. Comparative Examples 7 and 8 adjusted the amount of 1,3-propanediol in the modified polybutylene succinate. It was found that increasing the amount of 1,3-propanediol affected the thermal decomposition temperature of the specimens, but increasing the amount of 1,3-propanediol significantly reduced the mechanical properties of the specimens.

[0103] Experimental Example 2

[0104] Degradation test

[0105] The synthetic resins prepared in Examples 1-4 and Comparative Examples 1-5 were molded using a plate vulcanizer to form dumbbell-shaped specimens with a diameter of 40 mm, a width of 4 mm, and a thickness of 1 mm. The specimens were then buried in alluvial soil boxes obtained from farmland topsoil. Large clods and plant debris were screened out and removed from the soil. The specimens were buried at a depth of 10-15 cm, with a soil moisture content of 35% (by weight), and tested under constant temperature and humidity conditions (40℃, 60%RH). Every 20 days, the specimens were removed, washed with distilled water, and dried in a vacuum oven at 35±2℃ for three days. They were then weighed, and the mass loss rate (%) was calculated. The specific results are shown in Table 2.

[0106] Table 2

[0107] Group 20-day loss rate (%) 40-day loss rate (%) 60-day loss rate (%) Example 1 15.3 34.8 77.1 Example 2 12.5 32.0 72.4 Example 3 16.4 35.8 79.2 Example 4 18.9 40.5 85.3 Comparative Example 1 13.8 32.2 71.0 Comparative Example 2 13.1 31.9 70.2 Comparative Example 3 14.9 33.7 76.9 Comparative Example 4 10.4 28.6 67.5 Comparative Example 5 20.5 44.7 90.2 Comparative Example 6 13.4 28.5 65.4 Comparative Example 7 14.2 30.8 68.9 Comparative Example 8 17.2 39.9 82.4

[0108] As can be seen from the results in Table 2, the synthetic resins prepared in Examples 1-4 and Comparative Examples 1-8 of this invention exhibit excellent biodegradability. The degradation rate of the synthetic resin can be controlled by adjusting the amounts of hydroxyl-terminated biodegradable polyester elastomer, modified polybutylene succinate, and polyglycolic acid. The synthetic resin prepared in Comparative Example 1 using PBAT and unmodified polybutylene succinate also exhibits excellent biodegradability, but the data in Table 1 shows that its mechanical properties and thermal stability are significantly inferior to those of this application. Comparative Examples 2-5 have the same problems as Comparative Example 1. In Comparative Example 6, adjusting the amounts of dimethyl terephthalate and adipic acid in the hydroxyl-terminated biodegradable polyester elastomer resulted in a decreasing trend in the degradation rate of the synthetic resin. In Comparative Examples 7 and 8, adjusting the amount of 1,3-propanediol in the modified polybutylene succinate helped to improve the degradation rate of the synthetic resin.

[0109] Finally, it should be noted that the above embodiments are merely illustrative of several implementations of the present invention and are not intended to limit the scope of the invention. For those skilled in the art, any modifications, equivalent substitutions, or improvements made without departing from the concept of the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A biodegradable synthetic resin, characterized in that, The raw materials include the following parts by weight: 10-30 parts of hydroxyl-terminated biodegradable polyester elastomer, 60-80 parts of modified polybutylene succinate, 15-30 parts of polyglycolic acid resin, 5-10 parts of compatibilizer, 0.1-1 part of antioxidant and 0.1-1 part of lubricant; The specific preparation method of hydroxyl-terminated biodegradable polyester elastomer is as follows: Dimethyl terephthalate, 1,4-butanediol, ethylene glycol and tetrabutyl titanate are added to a stirrer and heated to 150-180℃ under nitrogen protection to carry out transesterification reaction. After 90% of the distillate produced during the reaction is distilled off, adipic acid is added, and the temperature is raised to 180-220℃ to carry out transesterification reaction. After all the distillate produced during the reaction is distilled off, the vacuum is drawn to 500Pa and the temperature is raised to 230-270℃. After reacting for 30 minutes, the vacuum is further drawn to below 100Pa and maintained for 4-6 hours. After the reaction is completed, the temperature is lowered to room temperature to obtain hydroxyl-terminated biodegradable polyester elastomer. The molar ratio of dimethyl terephthalate, 1,4-butanediol, ethylene glycol, adipic acid and tetrabutyl titanate is (50-60):(70-90):(15-25):(40-50):

2. The specific preparation method of modified polybutylene succinate is as follows: Succinic anhydride and p-toluenesulfonic acid are added to a reaction vessel, purged with argon gas, heated to 130-160℃, 1,4-butanediol and 1,3-propanediol are added, the reaction continues for 30 min, the temperature is raised to 180-200℃, the reaction is carried out for 3-4 h, and then cooled to room temperature to obtain product A. Product A is transferred to a vacuum distillation apparatus, purged with argon gas, a catalyst is added and stirred evenly, and a polycondensation reaction is carried out under vacuum for 1-1.5 h. After the reaction is completed, chloroform is added to dissolve the product, anhydrous methanol is added, the precipitate is rapidly stirred to precipitate, filtered, and dried to obtain modified polybutylene succinate; wherein, the weight ratio of succinic anhydride, toluenesulfonic acid, 1,4-butanediol and 1,3-propanediol is (90-100):(0.15-0.2):(90-110):(15-25); The amount of catalyst used is 0.05-0.5% of the weight of product A.

2. The biodegradable synthetic resin according to claim 1, characterized in that, The molecular weight of polyglycolic acid resin is 50,000-150,000.

3. The biodegradable synthetic resin according to claim 1, characterized in that, The compatibilizer is one or more of the following: styrene-acrylonitrile-maleic anhydride copolymer, ethylene-acrylate-glycidyl ester copolymer, ethylene-glycidyl ester, or ethylene-n-butyl acrylate-glycidyl ester copolymer; The antioxidant is one of hindered phenolic antioxidants or phosphite antioxidants; The lubricant is one or more of calcium stearate, magnesium stearate, zinc stearate, PE wax or PP wax.

4. The method for preparing the biodegradable synthetic resin according to any one of claims 1-3, characterized in that, Includes the following steps: S1. Take hydroxyl-terminated biodegradable polyester elastomer, modified polybutylene succinate, polyglycolic acid resin, compatibilizer, antioxidant and lubricant, mix them evenly, and then dry them. S2. After drying, the mixture is fed into a twin-screw extruder for melt blending and extrusion. The extruded material is cooled to room temperature and then pelletized by a pelletizer to obtain the biodegradable synthetic resin.

5. The method for preparing the biodegradable synthetic resin according to claim 4, characterized in that, In step S1, the mixing is carried out by using a high-speed mixer at a stirring speed of 500-700 r / min for 20-30 min.

6. The method for preparing the biodegradable synthetic resin according to claim 4, characterized in that, In step S2, the extrusion temperature of the twin-screw extruder is 200-220℃, the die temperature is 180-200℃, and the screw speed is 60-80 r / min.