Biodegradable polyester material as well as preparation method and application thereof

Abstract

The invention discloses a biodegradable polyester material as well as a preparation method and application thereof, and belongs to the technical field of high polymer materials. The biodegradable polyester material provided by the invention is prepared from the following components in parts by mass: 78 to 97 parts of biodegradable polyester composition, 3 to 22 parts of surface modified calcium carbonate, 0.05 to 0.55 part of chain extender and 0 to 1 part of processing aid, the biodegradable polyester composition comprises PBAT (poly (butylene adipate-co-terephthalate)), PLA (polylactic acid) and PPC (polypropylene carbonate), wherein the mass ratio of the PBAT to the PLA to the PPC is (80-90): (1-10): (1-10); the melt index of the PBAT at 190 DEG C / 2.16 kg is less than or equal to 10 g / 10 min; the molar content of D-lactic acid in the PLA is greater than or equal to 2%; the D50 particle size of the surface modified calcium carbonate is less than or equal to 2.2 microns. The biodegradable polyester material provided by the invention has excellent delayed edge sealing performance and puncture strength.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and particularly relates to a biodegradable polyester material, a preparation method thereof, and an application thereof. Background Art

[0002] With the development of the economy, the scale of domestic online shopping and express delivery services has been continuously expanding, but at the same time, it has also brought a large amount of packaging waste, especially plastic packaging waste. With the implementation of the plastic ban, the express packaging industry has also begun to seek replacement solutions. Due to its degradation characteristics, biodegradable polyester materials are currently widely used in express packaging. Existing biodegradable express packaging products are mainly modified polybutylene adipate terephthalate (PBAT) / polylactic acid (PLA), but there are problems such as poor puncture resistance. Moreover, in the actual production process, the blown film is generally not immediately printed and bagged, but is often placed for several days before bagging. However, during this process, affected by factors such as post-crystallization and the precipitation of small molecule components, the edge sealing performance of the film will gradually decrease and ultimately lead to unqualified delayed edge sealing heat sealing strength of biodegradable express packaging products. Therefore, how to improve the puncture and delayed edge sealing performance of biodegradable express packaging products has become the focus of the packaging industry. Summary of the Invention

[0003] An object of the present invention is to overcome the deficiencies of the above-mentioned prior art and provide a biodegradable polyester material with excellent puncture strength and delayed edge sealing performance, a preparation method thereof, and an application thereof.

[0004] To achieve the above object, in the first aspect of the present invention, the present invention provides a biodegradable polyester material, and the biodegradable polyester material comprises the following components in parts by mass:

[0005] 78 - 97 parts of a biodegradable polyester composition, 3 - 22 parts of surface-modified calcium carbonate, 0.05 - 0.55 parts of a chain extender, and 0 - 1 part of a processing aid;

[0006] The biodegradable polyester composition comprises PBAT, PLA, and poly(ethylene carbonate) (PPC), and the mass ratio of PBAT, PLA, and PPC is (80 - 90):(1 - 10):(1 - 10);

[0007] The melt index of the PBAT at 190°C / 2.16 kg ≤ 10 g / 10 min;

[0008] The molar content of D-lactic acid in the PLA ≥ 2%;

[0009] The D50 particle size of the surface-modified calcium carbonate ≤ 2.2 μm.

[0010] The biodegradable polyester material provided by the present invention can effectively improve the delayed edge sealing performance and puncture strength of the biodegradable polyester material by selecting components in appropriate mass proportions and by synergizing the components with each other.

[0011] Specifically, the present invention selects PBAT, PLA and PPC in a specific mass ratio range as a matrix, limits the melt index of PBAT and the molar content of D-lactic acid in PLA, and introduces a chain extender. The three can work together to improve the good puncture strength of the product with the help of PBAT with a low melt index and the chain extender. At the same time, the introduction of PPC can effectively improve the problem of decreased delayed edge sealing performance caused by increased puncture strength; in addition, the surface-modified calcium carbonate in a specific D50 particle size range can more effectively improve the puncture strength and delayed edge sealing performance of the product.

[0012] For example, the biodegradable polyester composition may be any point value or any range value between 78 and 97 parts, such as 80 to 95 parts, or 78 parts, 80 parts, 82 parts, 84 parts, 86 parts, 88 parts, 90 parts, 92 parts, 94 parts, 96 parts, 97 parts, etc.; the surface-modified calcium carbonate may be any point value or any range value between 3 and 22 parts, such as 5 to 20 parts, or 3 parts, 5 parts, 7 parts, 9 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, 2 0 part, 22 parts, etc.; the chain extender can be any point value or any two point range value between 0.05-0.55 parts, for example, it can be 0.1-0.5 parts, or it can be 0.05 parts, 0.1 parts, 0.15 parts, 0.2 parts, 0.25 parts, 0.3 parts, 0.35 parts, 0.4 parts, 0.45 parts, 0.5 parts, 0.55 parts, etc.; the processing aid can be any point value or any two point range value between 0-1 parts, for example, it can be 0.1 parts, 0.2 parts, 0.4 parts, 0.6 parts, 0.8 parts, 1 parts, etc.

[0013] Preferably, in the biodegradable polyester material, the mass percentage of the biodegradable polyester composition is ≥ 76%.

[0014] More preferably, in the biodegradable polyester material, the mass percentage of the biodegradable polyester composition is 79-95%.

[0015] It should be noted that the melt index of the PBAT is obtained by referring to GB / T 3682-2000 test, and the test conditions are 190°C / 2.16kg.

[0016] Exemplarily, the melt index of the PBAT at 190 °C / 2.16 kg can be any point value or any two-point range value within ≤ 10 g / 10 min. For example, it can be 2 - 8 g / 10 min, 4 - 8 g / 10 min, or it can be 1 g / 10 min, 1.5 g / 10 min, 2 g / 10 min, 3 g / 10 min, 4 g / 10 min, 5 g / 10 min, 6 g / 10 min, 7 g / 10 min, 8 g / 10 min, 9 g / 10 min, 10 g / 10 min, etc.

[0017] It should be noted that in the PBAT, the molar amount of terephthalic acid accounts for 43.5 - 52.0% of the sum of the molar amounts of terephthalic acid and adipic acid. Preferably, the molar amount of terephthalic acid accounts for 46.5 - 49.5% of the sum of the molar amounts of terephthalic acid and adipic acid. The test method for the proportion of the molar amount of terephthalic acid in the sum of the molar amounts of terephthalic acid and adipic acid refers to 202111076704.3.

[0018] It should be noted that the molar content of D-lactic acid in the PLA is obtained by gas chromatography testing.

[0019] Exemplarily, the molar content of D-lactic acid in the PLA can be any point value or any two-point range value within ≥ 2%. For example, it can be 3 - 13%, 4 - 12%, 4 - 8%, 8 - 12%, or it can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, etc.

[0020] It should be noted that the D50 particle size of the filler is obtained by laser particle size analyzer method testing.

[0021] Exemplarily, the D50 particle size of the filler can be any point value or any two-point range value within ≤ 2.2 μm. For example, it can be 0.7 - 2 μm, 1.5 - 2 μm, or it can be 0.5 μm, 1 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2.0 μm, 2.2 μm, etc.

[0022] As a preferred embodiment of the biodegradable polyester material of the present invention, the biodegradable polyester material comprises the following components in parts by mass: 85 - 90 parts of biodegradable polyester composition, 10 - 15 parts of surface-modified calcium carbonate, 0.2 - 0.3 parts of chain extender, and 0.1 - 1 part of processing aid.

[0023] The present invention's research finds that the parts by mass of the components in the biodegradable polyester material will also affect the performance of the product. When further selecting the parts by mass of the components in the biodegradable polyester material within the above range, the comprehensive effect of the obtained product is better.

[0024] As a preferred embodiment of the biodegradable polyester material of the present invention, the melt index of the PBAT at 190 °C / 2.16 kg is 2 - 8 g / 10 min.

[0025] As a preferred embodiment of the biodegradable polyester material of the present invention, the molar content of D-lactic acid in the PLA is 3 - 13%.

[0026] Exemplarily, the molar content of D-lactic acid in the PLA can be a point value or any two-point range value between 3 - 13%, such as 4 - 12%, 4 - 8%, 8 - 12%, etc., or can be 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, etc.

[0027] Preferably, the molar content of D-lactic acid in the PLA is 6 - 10%.

[0028] The present invention's research found that the molar content of D-lactic acid in the PLA will affect its own crystallization performance and degradation performance, etc., and will also have different interactions with other components. When further selecting the molar content of D-lactic acid in the PLA to be 3 - 13%, especially 6 - 10%, the resulting product has better delayed side-sealing performance.

[0029] As a preferred embodiment of the biodegradable polyester material of the present invention, the melt index of the PPC at 170 °C / 2.16 kg is 1 - 11 g / 10 min.

[0030] It should be noted that the melt index of the PPC at 170 °C / 2.16 kg is obtained by referring to GB / T3682 - 2000 for testing.

[0031] Exemplarily, the melt index of the PPC at 170 °C / 2.16 kg can be any point value or any two-point range value between 1 - 11 g / 10 min, such as 2 - 10 g / 10 min, 2 - 5 g / 10 min, 5 - 10 g / 10 min, etc., or can be 1 g / 10 min, 2 g / 10 min, 3 g / 10 min, 4 g / 10 min, 5 g / 10 min, 6 g / 10 min, 7 g / 10 min, 8 g / 10 min, 9 g / 10 min, 10 g / 10 min, 11 g / 10 min, etc.

[0032] Preferably, the melt index of the PPC at 170 °C / 2.16 kg is 4 - 6 g / 10 min.

[0033] The research of the present invention finds that the melt index of the PPC resin will affect its interaction with other components. When the melt index of the PPC resin is further selected within the above range, excellent time-delay side-sealing performance of the product can be well achieved.

[0034] As a preferred embodiment of the biodegradable polyester material of the present invention, the D50 particle size of the surface-modified calcium carbonate is 1 - 1.5 μm.

[0035] The research of the present invention finds that the D50 particle size of the surface-modified calcium carbonate will affect its dispersion in the system, thereby affecting the puncture strength and time-delay side-sealing performance of the biodegradable polyester material; when the D50 particle size of the surface-modified calcium carbonate is further selected within the above range, the comprehensive performance of the obtained product is more excellent.

[0036] As a preferred embodiment of the biodegradable polyester material of the present invention, the surface-modified calcium carbonate is obtained by being treated with a surface treatment agent, and the surface treatment agent includes at least one of a silane coupling agent, a titanate coupling agent, a phosphate coupling agent, an aluminate coupling agent, and stearic acid.

[0037] Exemplarily, the silane coupling agent can be KH-550, KH-560, etc.; the titanate coupling agent can be KR-TTS, NDZ-101, etc.; the phosphate coupling agent can be KR-12, NDZ-210, etc.; the aluminate coupling agent can be NDZ-301, LICA 12, etc.

[0038] Preferably, based on the mass of calcium carbonate, the addition amount of the surface treatment agent is 0.6 - 1.4%.

[0039] It should be noted that the surface-modified calcium carbonate is surface-modified by conventional treatment means, such as using equipment such as a honeycomb mill, a nail disc mill, or a high-speed mixer for modification treatment.

[0040] As a preferred embodiment of the biodegradable polyester material of the present invention, the chain extender includes at least one of an epoxy group-containing chain extender and an epoxy resin.

[0041] Exemplarily, the epoxy group-containing chain extender includes ADR series chain extenders produced by BASF.

[0042] As a preferred embodiment of the biodegradable polyester material of the present invention, the processing aid includes at least one of a lubricant, an antiblocking agent, and an antioxidant.

[0043] Exemplarily, the lubricant includes at least one of PE wax, Fischer-Tropsch wax, erucamide, etc.; the opening agent includes at least one of erucamide, oleamide, etc.; the antioxidant includes at least one of hindered phenol antioxidants, phosphite antioxidants, and thioether antioxidants.

[0044] Exemplarily, the hindered phenol antioxidant can be antioxidant 1010, antioxidant 1076, etc.; the phosphite antioxidant can be antioxidant 168, antioxidant 627AV, etc.; the thioether antioxidant can be antioxidant 412S, antioxidant DLTP, etc.

[0045] In the second aspect of the present invention, the present invention provides a method for preparing the biodegradable polyester material, and the preparation method includes the following steps: mixing the components evenly and then melt-extruding to obtain the biodegradable polyester material.

[0046] As a preferred embodiment of the preparation method of the present invention, in the melt extrusion, the temperature is 130 - 200 °C, the rotation speed is 200 - 400 rpm, and the feeding rate is 400 - 1000 kg / h.

[0047] In the third aspect of the present invention, the present invention provides a film or bag, and the film or bag is prepared from the biodegradable polyester material of the present invention.

[0048] As a preferred embodiment of the application of the present invention, the preparation method of the film or bag is: blow-molding and bag-making the biodegradable polyester material to obtain the film or bag.

[0049] Preferably, when blow-molding, the temperature of the extruder is 130 - 180 °C, the blow-up ratio is (2 - 4):1, and the thickness is 45 - 55 μm; when bag-making, the rate of the bag-making machine is 90 - 110 pieces / min, and the temperature is 250 - 400 °C.

[0050] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0051] A biodegradable polyester material provided by the present invention can effectively improve the delayed side-sealing performance and puncture strength of the biodegradable polyester material through selecting appropriate mass parts of components and the mutual coordination between the components; specifically, the puncture strength of the obtained product is above 2.1 N / 50 μm, and the heat-sealing strength of the 10-day delayed side-sealing is above 16.8 N / 15 mm. At the same time, the preparation method of the biodegradable polyester material provided by the present invention is simple in operation, which is beneficial to actual production. Specific Embodiments

[0052] To better illustrate the purpose, technical solution and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0053] The reagents, methods and equipment used in the present invention are all conventional reagents, methods and equipment in the art unless otherwise specified; and unless otherwise specified, the raw materials used in parallel experiments are from the same batch.

[0054] PBAT-1: KB100 NC801, melt index 4 g / 10 min, produced by Jinfa Biology;

[0055] PBAT-2: KB100 LF NC801, melt index 2 g / 10 min, produced by Jinfa Biology;

[0056] PBAT-3: KB100 HF NC801, melt index 8 g / 10 min, produced by Jinfa Biology;

[0057] PBAT-4: KB100 SF NC801, melt index 16 g / 10 min, produced by Jinfa Biology;

[0058] PLA-1: LX930, molar content of D-lactic acid 8%, produced by Total;

[0059] PLA-2: FY804, molar content of D-lactic acid 4%, produced by Fengyuan Futailai;

[0060] PLA-3: LX975, molar content of D-lactic acid 12%, produced by Total;

[0061] PLA-4: FY801, molar content of D-lactic acid < 1%, produced by Fengyuan Futailai;

[0062] PPC-1: PPC-P LX101, melt index 5 g / 10 min, produced by Lianxin Environmental Protection Technology;

[0063] PPC-2: YX-2001, melt index 2 g / 10 min, produced by Yixian Technology;

[0064] PPC-3: PPC-P, melt index 10 g / 10 min, produced by Tianxin New Materials;

[0065] Surface-modified calcium carbonate 1: The surface treatment agent is silane coupling agent (KH560), D50 particle size is 1 μm, self-made;

[0066] Surface-modified calcium carbonate 2: The surface treatment agent is silane coupling agent (KH560), D50 particle size is 1.5 μm, self-made;

[0067] Surface-modified calcium carbonate 3: The surface treatment agent is silane coupling agent (KH560), D50 particle size is 2 μm, self-made;

[0068] Surface-modified calcium carbonate 4: The surface treatment agent is silane coupling agent (KH560), D50 particle size is 0.7μm, self-made;

[0069] Surface-modified calcium carbonate 5: The surface treatment agent is titanate coupling agent (HY-102), D50 particle size is 1μm, self-made;

[0070] Surface-modified calcium carbonate 6: FilmLink 520, the surface treatment agent is stearic acid, D50 particle size is 2μm, Imerys;

[0071] Surface-modified calcium carbonate 7: The surface treatment agent is silane coupling agent (KH560), D50 particle size is 3μm, self-made;

[0072] Calcium carbonate: ACC-812 raw powder, without surface treatment agent, D50 particle size is 1μm, Xinrong;

[0073] Chain extender 1: ADR 4468, ADR series chain extender, BASF;

[0074] Chain extender 2: 0199, epoxy resin, Xingchen Synthetic Materials;

[0075] Antioxidant: Antioxidant 168, commercially available.

[0076] Among them, the preparation method of surface-modified calcium carbonate 1 includes the following steps: Put calcium carbonate raw powder and 2wt% of silane coupling agent into a high-speed mixer, first mix at a low speed of 150rpm for 5min to make the calcium carbonate raw powder and silane coupling agent mix evenly, then mix at a high speed of 1000rpm for 15min to make the silane coupling agent evenly coated on the surface of the calcium carbonate raw powder, and then mix at a low speed of 150rpm for 5min to cool the temperature of the surface-treated calcium carbonate powder to within 80°C to obtain surface-modified calcium carbonate 1;

[0077] The change of the D50 particle size of the surface-modified calcium carbonate is achieved by changing the D50 particle size of the calcium carbonate raw powder; the change of the surface modifier of the surface-modified calcium carbonate is achieved by changing the type of the surface treatment agent.

[0078] Examples 1-17 and Comparative Examples 1-8

[0079] The examples and comparative examples of the present invention provide a biodegradable polyester material, and the component contents (parts by weight) of the biodegradable polyester material are shown in Table 1-2;

[0080] Table 1

[0081]

[0082] Table 2

[0083]

[0084]

[0085] Table 3

[0086] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 PBAT-1 82 82 70 89 82 82 / 82 PBAT-4 / / / / / / 82 PLA-1 8 15 0.5 4 4 4 PLA-4 4 PPC-1 8 5 0.5 4 4 4 4 Surface Modified Calcium Carbonate 1 12 12 12 12 / / 12 12 Surface Modified Calcium Carbonate 7 / / / / 12 / / Calcium Carbonate / / / / / 12 / Chain Extender 1 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Antioxidant 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1

[0087] The preparation method of the biodegradable polyester material provided in Example 1 is as follows:

[0088] After weighing and mixing the dried raw materials, they are fed into a twin-screw extruder, and after extrusion, strand drawing, cooling, pelletizing, and drying, the biodegradable polyester material is obtained;

[0089] Among them, the parameters of the twin-screw extruder are: the length-diameter ratio of the twin-screw extruder is 48:1, the screw rotation speed is 300 rpm, and the extrusion temperatures of each zone are 120 °C, 180 °C, 180 °C, 180 °C, 180 °C, 180 °C, 180 °C, 180 °C, 180 °C, 180 °C, 180 °C, 180 °C respectively.

[0090] The preparation methods of the biodegradable polyester materials provided in Examples 2-17 and Comparative Examples 1-8 are the same as those in Example 1, and those without relevant components can be omitted.

[0091] Effect Example

[0092] The effect examples of the present invention verify the performance of the biodegradable polyester materials prepared in the examples and comparative examples; the prepared biodegradable polyester materials are blown into films, and after blowing, the puncture strength is tested, and then transferred to a bag-making machine for bag-making: when blowing the film, the temperature of the extruder is 150 °C, the blow-up ratio is 3:1, and the thickness is 50 μm; when making bags, the speed of the bag-making machine is set to 100 pieces / min, and the temperature is 300 °C;

[0093] 1. Puncture strength test: The prepared biodegradable polyester materials are blown into films, and after blowing, the puncture strength is tested according to GB / T 38727-2020. A test piece with a diameter of 100 mm is installed on the sample film fixing clamp ring, and then a steel needle with a diameter of 1.0 mm and a spherical tip radius of 0.5 mm is used to pierce it at a speed of (50 ± 5) mm / min, and the maximum load at which the steel needle penetrates the test piece is read. The number of test pieces is more than 5, and the arithmetic mean value is taken;

[0094] 2. Heat-sealing strength test: The prepared biodegradable polyester material is blown into a film. After blowing the film, it is left for 10 days, and then transferred to a bag-making machine to make bags, obtaining biodegradable express bags. When blowing the film, the temperature of the extruder is 150 °C, the blow-up ratio is 3:1, and the thickness is 50 μm. When making bags, the speed of the bag-making machine is set at 100 pieces / min, and the temperature is 300 °C. According to GB / T38727-2020 for testing, on the side of the biodegradable express bag, perpendicular to the heat-sealed part, randomly take samples. With the heat-sealed part as the center, open it to 180°. Clamp the two ends of the sample on the two clamps of the testing machine. The axis of the sample should coincide with the center line of the upper and lower clamps, and it is required to be properly tightened to prevent the sample from slipping off or breaking in the clamp before the experiment. The distance between the clamps is 50 mm, and the test speed is (300 ± 20) mm / min. Read the maximum load when the sample breaks. The test result takes the arithmetic mean of 10 samples as the heat-sealing strength of this part;

[0095] 3. Bag-making performance: The prepared biodegradable polyester material is blown into a film. After blowing the film, 100 bags are continuously made. If 100 bags can be successfully made continuously and the appearance of the prepared bags is good, it is recorded as "normal". If 100 bags cannot be successfully made continuously, it is recorded as "unable to prepare". If there are obvious appearance defects such as crystal points and holes after bag-making, it is recorded as "unusable";

[0096] The test results are shown in Table 3;

[0097] Table 3

[0098]

[0099]

[0100] As can be seen from Table 3, when the technical solution of the present invention is adopted, the obtained biodegradable polyester material has a high puncture strength and a 10-day delayed side-sealing heat-sealing strength. The puncture strength is above 2.1 N / 50 μm, and the 10-day delayed side-sealing heat-sealing strength is above 16.0 N / 15 mm, and the obtained biodegradable polyester compositions can all be used for normal bag making; from Examples 1 and Comparative Examples 1-4, it can be seen that the types of polyesters and their mass ratios in the biodegradable polyester composition provided by the present invention have a significant impact on the comprehensive performance of the product; when PPC is not added in Comparative Example 1, the 10-day delayed side-sealing heat-sealing strength of the obtained product is only 9.5 N, which does not meet the product requirements; when PLA is not added in Comparative Example 2, although the puncture strength and the 10-day delayed side-sealing heat-sealing strength of the obtained product meet the product requirements, the film is too soft, resulting in difficulty in smooth bag making during the bag-making process and thus unable to be produced smoothly; when the mass ratios of PBAT, PLA and PPC in Comparative Examples 3-4 are not within the ranges given by the present invention, the obtained products are similar to those in Comparative Examples 1 and 2. Among them, the heat-sealing strength of the product in Comparative Example 3 does not meet the requirements, and the film of the product in Comparative Example 4 is too soft after blown film, resulting in inability to be produced smoothly during bag making;

[0101] As can be seen from Example 1, Examples 13-16 and Comparative Examples 5-6, the type of filler and the D50 particle size will affect the comprehensive performance of the product. When the D50 particle size of the filler used in Comparative Example 5 is not within the range given by the present invention, although the puncture strength of the obtained product can reach 2.0 N / 50 μm, the too large particle size results in too rough film surface, which is not conducive to bag side-sealing, thus resulting in the heat-sealing strength not meeting the requirements; when unmodified calcium carbonate is used in Comparative Example 6, although its puncture strength and 10-day delayed side-sealing heat-sealing strength can both meet the requirements, due to the difficulty of achieving good dispersion of unmodified calcium carbonate in the biodegradable polyester composition, although it can be blown film conventionally, due to poor dispersion, there are a large number of calcium carbonate agglomeration points on the film appearance, and the surface of the product after bag making is too rough to be used;

[0102] As can be seen from Example 1, Examples 6-7 and Comparative Example 7, the melt index of PBAT will also affect the comprehensive performance of the product. When the melt index of PBAT in Comparative Example 7 is too large and not within the range given by the present invention, the puncture strength of the obtained product decreases significantly;

[0103] As can be seen from Example 1, Examples 10-11 and Comparative Example 8, the D-lactic acid molar content of PLA will also affect the comprehensive performance of the product. When the D-lactic acid molar content of PLA in Comparative Example 8 is not within the range given by the present invention, the 10-day delayed side-sealing heat-sealing strength of the obtained product decreases significantly.

[0104] Finally, it should be noted that the above embodiments are used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A biodegradable polyester material, characterized in that, The biodegradable polyester material comprises the following components in parts by mass: 78 - 97 parts of biodegradable polyester composition, 3 - 22 parts of surface - modified calcium carbonate, 0.05 - 0.55 parts of chain extender, 0 - 1 part of processing aid; The biodegradable polyester composition comprises PBAT, PLA and PPC, and the mass ratio of PBAT, PLA and PPC is (80 - 90):(1 - 10):(1 - 10); The melt index of the PBAT at 190 °C / 2.16 kg ≤ 10 g / 10 min; The molar content of D - lactic acid in the PLA ≥ 2%; The D50 particle size of the surface - modified calcium carbonate ≤ 2.2 μm.

2. The biodegradable polyester material according to claim 1, characterized in that, The biodegradable polyester material comprises the following components in parts by mass: 85 - 90 parts of biodegradable polyester composition, 10 - 15 parts of surface - modified calcium carbonate, 0.2 - 0.3 parts of chain extender, 0.1 - 1 part of processing aid.

3. The biodegradable polyester material according to claim 1, wherein The melt index of the PBAT at 190 °C / 2.16 kg is 2 - 8 g / 10 min.

4. The biodegradable polyester material according to claim 1, characterized in that, The molar content of D - lactic acid in the PLA is 3 - 13%.

5. The biodegradable polyester material according to claim 1, wherein The melt index of the PPC at 170 °C / 2.16 kg is 1 - 11 g / 10 min.

6. The biodegradable polyester material according to claim 1, wherein The D50 particle size of the surface - modified calcium carbonate is 1 - 1.5 μm.

7. The biodegradable polyester material according to claim 6, wherein, The surface - modified calcium carbonate is obtained by being treated with a surface treatment agent, and the surface treatment agent comprises at least one of silane coupling agent, titanate coupling agent, phosphate ester coupling agent, aluminate coupling agent, stearic acid.

8. The biodegradable polyester material according to claim 1, wherein The chain extender comprises at least one of ADR series chain extenders and epoxy resin.

9. The preparation method of the biodegradable polyester material according to any one of claims 1-8, characterized in that, The preparation method comprises the following steps: Mix the components evenly and then melt - extrude to obtain the biodegradable polyester material.

10. A membrane or bag, characterized in that, The film or bag is prepared from the biodegradable polyester material of the present invention.

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