PBAT composite material and preparation method and application thereof

Abstract

The invention relates to a PBAT composite material and a preparation method and application thereof. The PBAT composite material is prepared from the following components in parts by weight: 3 to 20 parts of polylactic acid, 40 to 80 parts of PBAT resin, 0.1 to 10 parts of polyester and 10 to 40 parts of filler. According to the invention, the content of terephthalic acid derived units in the PBAT resin is regulated and controlled, and the polylactic acid, the filler and a certain amount of polyester with specific content of terephthalic acid derived units are added, so that the obtained PBAT composite material keeps good degradation performance and also has good film blowing opening performance and printing performance.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer material modification, and more specifically, to a PBAT composite material and a preparation method and application thereof. Background Art

[0002] With the accelerated elimination of obsolete production capacity and the continuous advancement of industrial structure adjustment, many businesses in the environmental protection industry are penetrating from end-of-pipe treatment to various production links. In the film industry, fully biodegradable films have received attention from most countries and are expected to solve the problem of white pollution.

[0003] PBAT, a highly biodegradable material, combines the properties of PBA and PBT, offering excellent ductility and elongation at break, as well as good heat resistance and impact resistance. However, PBAT suffers from poor processing properties and poor film opening during blow molding, hindering its widespread adoption.

[0004] In the prior art, anti-blocking agents (e.g., erucamide, oleamide, etc.) are often added to improve the anti-blocking properties of PBAT materials. However, anti-blocking agents are often small molecules that easily migrate to the surface of the product, resulting in poor ink adhesion.

[0005] Patent CN 103709687A improves the opening performance of the film material by adding Ciba's anti-adhesive agent SR100 to PBAT, but does not focus on the printing performance of the material.

[0006] Therefore, it is necessary to develop technology to solve the problem that the current PBAT material's film blowing opening performance and printing performance cannot be taken into account at the same time. Summary of the Invention

[0007] The primary purpose of the present invention is to overcome the problem that the film blowing opening performance and printing performance of the PBAT material in the current technology cannot be taken into account at the same time, and to provide a PBAT composite material.

[0008] A further object of the present invention is to provide a method for preparing the above-mentioned PBAT composite material.

[0009] A further object of the present invention is to provide an application of the above-mentioned PBAT composite material in the preparation of film products.

[0010] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0011] A PBAT composite material comprises the following components in parts by weight:

[0012]

[0013]

[0014] In the PBAT resin, the proportion of terephthalic acid-derived units relative to all dicarboxylic acid-derived units is 44 to 52 mol%, specifically it can be 44 mol%, 45 mol%, 46 mol%, 48 mol%, 50 mol% or 52 mol%;

[0015] In the polyester, the dicarboxylic acid-derived units are derived from terephthalic acid and C 4～10 aliphatic dicarboxylic acids, and the proportion of terephthalic acid-derived units relative to all dicarboxylic acid-derived units is 55 to 80 mol% (specifically it can be 55 mol%, 58 mol%, 60 mol%, 62 mol%, 65 mol%, 68 mol%, 70 mol%, 72 mol%, 75 mol%, 78 mol% or 80 mol%), and the diol-derived units are derived from butanediol. In the present invention, the content of the proportion of terephthalic acid-derived units in the PBAT resin or polyester relative to all dicarboxylic acid-derived units can be measured by nuclear magnetic resonance.

[0016] The inventors of the present invention have found through research that adding polylactic acid to the PBAT composite material can improve the crystallinity of the material to a certain extent and improve the film blowing opening performance of the material.

[0017] The inventors further found that on the basis of adding polylactic acid, by further regulating the content of terephthalic acid-derived units in the PBAT resin and adding a polyester with a specific content of terephthalic acid-derived units, the opening performance of the PBAT composite material can be significantly improved without adding an opening agent and a lubricant, and it has good adhesion to ink and good printing performance. The reason may be that by regulating the content of terephthalic acid-derived units in the PBAT resin and regulating the dosage and the content of terephthalic acid-derived units of the polyester, the hardness, melting point and crystallinity of the material can be more effectively regulated, thereby effectively improving the opening performance of the material while maintaining the printing performance.

[0018] If the content of terephthalic acid-derived units in the PBAT resin is too low, or a polyester with a specific content of terephthalic acid-derived units is not added, the opening performance of the PBAT composite material cannot be improved well. If the content of terephthalic acid-derived units in the PBAT resin is too high, or too much polyester with a specific content of terephthalic acid-derived units is added, it will have a negative impact on the degradation performance of the PBAT composite material and cannot meet its conventional application requirements.

[0019] The addition of fillers is also helpful for improving the opening performance and printing performance of the PBAT composite material.

[0020] That is, the present invention regulates the content of terephthalic acid-derived units in PBAT resin, and adds polylactic acid, filler, and a polyester with a specific content of terephthalic acid-derived units, so that the obtained PBAT composite material maintains good degradation performance while taking into account good film blowing opening performance and printing performance.

[0021] Optionally, the melt mass flow rate of the polylactic acid is 1-10 g / 10 min.

[0022] In the present invention, the melt mass flow rate of polylactic acid is measured according to ISO 1133 using a weight of 2.16 kg and at a temperature of 190 °C.

[0023] Preferably, the melt mass flow rate of the polylactic acid is 4-4.5 g / 10 min. When polylactic acid with this melt mass flow rate is selected, the degradation performance of the obtained PBAT composite material is better maintained.

[0024] Preferably, the residual monomer content of the polylactic acid ≤ 0.5 wt%.

[0025] Optionally, the intrinsic viscosity of the PBAT resin is 0.9 dL / g - 1.5 dL / g.

[0026] In the present invention, the intrinsic viscosity of the PBAT resin is determined according to DIN 53728, Part 3 of January 3, 1985. The solvent used includes a mixture of the following phenol and dichlorobenzene compounded in a weight ratio of 50:50; the test temperature is 25 °C.

[0027] Preferably, the intrinsic viscosity of the PBAT resin is 1.3 dL / g - 1.5 dL / g. In this range, the printing performance of the obtained PBAT composite material is better.

[0028] Preferably, in the PBAT resin, the proportion of terephthalic acid-derived units relative to all dicarboxylic acid-derived units is 48-52 mol%. In this range, the printing performance of the obtained PBAT composite material is better.

[0029] Optionally, the intrinsic viscosity of the polyester is 1.3 dL / g - 1.5 dL / g.

[0030] In the present invention, the intrinsic viscosity of the polyester is determined according to DIN 53728, Part 3 of January 3, 1985. The solvent used includes a mixture of the following phenol and dichlorobenzene compounded in a weight ratio of 50:50; the test temperature is 25 °C.

[0031] Preferably, in the polyester, the proportion of terephthalic acid-derived units relative to all dicarboxylic acid-derived units is 65 to 80 mol%, and within this range, the blown film opening performance and printing performance of the obtained PBAT composite material are better.

[0032] Optionally, the polyester is at least one of poly(butylene succinate terephthalate), poly(butylene adipate terephthalate), poly(butylene azelate terephthalate), or poly(butylene sebacate terephthalate).

[0033] Preferably, the polyester is poly(butylene sebacate terephthalate). When poly(butylene sebacate terephthalate) is selected, the printing performance of the obtained PBAT composite material is better.

[0034] Optionally, the filler is at least one of calcium carbonate, talc, kaolin, mica powder, or montmorillonite.

[0035] Optionally, the D50 particle size of the filler is ≤ 10 μm.

[0036] In the present invention, the D50 particle size of the filler can be measured according to GB / T 19077.1 "Particle Size Analysis - Laser Diffraction Method".

[0037] Optionally, the PBAT composite material further includes 0.1 to 2 parts of other additives.

[0038] Optionally, the other additives are at least one of antioxidants, stabilizers, antistatic agents, antifogging agents, UV absorbers, or UV stabilizers.

[0039] Generally, the dosages of the respective other additives are as follows: 0.01 to 0.3 parts by weight of antioxidant, 0.05 to 1 part by weight of stabilizer, 0.01 to 0.5 part by weight of antistatic agent, 0.05 to 2 parts by weight of UV absorber, and 0.1 to 3 parts by weight of UV stabilizer.

[0040] Optionally, the antioxidant is at least one of antioxidant 1010 or antioxidant 168;

[0041] Optionally, the stabilizer is at least one of tribasic lead sulfate, dibasic lead stearate, lead stearate, calcium stearate, zinc stearate, or magnesium stearate;

[0042] Optionally, the antistatic agent is at least one of ethoxylated alkylamine, ethoxylated alkylamide, or glycerol monostearate;

[0043] Optionally, the antifogging agent is at least one of glycerol esters, polyglycerol esters, sorbitan esters, ethoxylated derivatives, ethoxylated nonylphenol, or ethoxylated alcohols;

[0044] Optionally, the UV absorber is at least one of phenyl salicylate, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone or 2-hydroxy-4-n-octyloxybenzophenone.

[0045] Optionally, the UV stabilizer is at least one of bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate or 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-5-(2,4-dimethylphenyl)-2H-benzotriazol-4-one.

[0046] Preferably, the PBAT composite material comprises the following components in parts by weight:

[0047]

[0048] The preparation method of the above PBAT composite material comprises the following steps: mixing the components, melt-extruding, and pelletizing to obtain the PBAT composite material.

[0049] The application of the above PBAT composite material in the preparation of film products is also within the protection scope of the present invention.

[0050] Preferably, the film product is a shopping bag, a garbage bag or a packaging bag.

[0051] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0052] The present invention regulates the content of terephthalic acid-derived units in the PBAT resin, and adds polylactic acid, fillers and a certain amount of polyester with a specific content of terephthalic acid-derived units, so that the obtained PBAT composite material maintains good degradation performance, and at the same time takes into account good film blowing opening performance and printing performance. Detailed embodiments

[0053] In order to more clearly and completely describe the technical solutions of the present invention, the present invention will be further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention, and various changes can be made within the scope defined by the rights of the present invention.

[0054] Some of the reagents selected in the embodiments and comparative examples of the present invention are described as follows:

[0055] Polylactic acid 1#: purchased from Nature Works, grade: PLA 4044D, melt index: 4.5 g / 10 min;

[0056] Polylactic acid 2#: purchased from Nature Works, PLA 3001D, melt index: 10 g / 10 min;

[0057] Polylactic acid 3#: Purchased from Nature Works, PLA 752-27, with a melt index of 4.0 g / 10 min;

[0058] The residual monomer content of the polylactic acid of the present invention was tested as follows:

[0059] 1. Preparation of standard solution

[0060] (1) Weigh 100 ± 10 mg of pentamethylbenzene and prepare it into a 100 mL dichloromethane solution, and shake well. Denote it as the internal standard solution;

[0061] (2) Weigh 100 ± 10 mg of L-lactide standard and prepare it into a 100 mL dichloromethane solution, and shake well. Denote it as the standard solution;

[0062] (3) Take volumes of 1.0, 2.0, 5.0, 10.0, and 20.0 mL from the standard solution into 25 mL volumetric flasks respectively, then add 4.0 mL of the internal standard solution to each, fill with n-hexane, and shake well at a constant temperature. Denote it as the calibration standard solution.

[0063] 2. Sample testing

[0064] (1) Weigh 200 ± 20 mg of the polylactic acid sample (W) in a 20 ml glass vial, and add 4.0 mL of the internal standard solution. Dissolve the sample at room temperature, and stirring can be used to assist dissolution. After the sample is completely dissolved, slowly add 10 mL of n-hexane to the inner wall of the flask, tightly stopper the vial, then shake vigorously for 5 - 10 s, and let the sample stand for 10 minutes;

[0065] (2) After filtering with a membrane filter, transfer it to a special injection vial for gas chromatography and test according to the above gas chromatography analysis conditions. Each sample solution should be injected at least 3 times.

[0066] 3. Calculation of the residual monomer content of polylactic acid

[0067] Calculate the area ratio ARS of lactide and pentamethylbenzene in the injected sample, and read the corresponding content ratio CRS from the calibration curve.

[0068] The lactide content in each GC run of the sample is calculated as follows:

[0069]

[0070] CRS: Content ratio read from the calibration curve;

[0071] ISS: Mass of pentamethylbenzene present in 100 mL of the internal standard solution used for sample determination [mg / 100 mL];

[0072] W: Mass of the PLA sample weighed [mg].

[0073] PBAT Resin 1#: Self-made, and the preparation method is as follows:

[0074] 1) Add terephthalic acid and 1,4-butanediol into the esterification reactor according to the molar ratio of 1:1.2, and add 1% of the total mass of the raw materials of n-butyl titanate as the catalyst. React for 2.5 h at a temperature of 240 °C and a pressure of 40 KPa to obtain esterified product A1;

[0075] 2) Add adipic acid and 1,4-butanediol into the esterification reactor according to the molar ratio of 1:1.3. React for 2.5 h at a temperature of 200 °C and a pressure of 40 KPa to obtain esterified product A2;

[0076] 3) Continuously feed the two esterified products A1 and A2 into a mixer for mixing. The mass flow ratio is 1:1. React for 2.5 h at a temperature of 240 °C and a pressure of 4 KPa to obtain a prepolymer, and then continue to polymerize for 2.5 h at a temperature of 200 °C and a pressure of 120 Pa to obtain PBAT Resin 1#. The T content (the proportion of the terephthalic acid-derived unit relative to all dicarboxylic acid-derived units) is 48 mol%; the intrinsic viscosity is 1.36 dL / g

[0077] The T content can be measured by nuclear magnetic resonance. The specific process is as follows: Test the nuclear magnetic resonance hydrogen spectrum of the sample and calculate the peak area of the corresponding peak to measure the mole fraction of the polybutylene terephthalate segment in the sample. Taking PBAT Resin 1# as an example, the calculation method is as follows:

[0078] T = A 8.09 / (A 8.09 + A 2.33 )

[0079] Among them, T represents the mole fraction of polybutylene terephthalate in PBAT, that is, the molar proportion of the terephthalic acid-derived unit relative to all dicarboxylic acid-derived units;

[0080] A 8.09 represents the peak area at 8.09 in the nuclear magnetic resonance spectrum;

[0081] A 2.33 represents the peak area at 2.33 in the nuclear magnetic resonance spectrum

[0082] The measurement process of the T content of other PBAT resins or polyesters is the same.

[0083] PBAT Resin 2#: Self-made, and the preparation method is basically the same as that of PBAT Resin 1#. The difference is that in step 3), the T content is adjusted by adjusting the mass flow ratio of A1 and A2. Finally, PBAT Resin 2# is obtained, with a T content of 45 mol%; the intrinsic viscosity is 1.35 dL / g.

[0084] PBAT Resin 3#: Self-made. The preparation method is basically the same as that of PBAT Resin 1#, except that in step 3), the T content is adjusted by adjusting the mass flow ratio of A1 and A2. Finally, PBAT Resin 3# is obtained, with a T content of 52 mol%; the intrinsic viscosity is 1.36 dL / g.

[0085] PBAT Resin 4#: Self-made. The preparation method is basically the same as that of PBAT Resin 1#, except that in step 3), the T content is adjusted by adjusting the mass flow ratio of A1 and A2. Finally, PBAT Resin 4# is obtained, with a T content of 50 mol%; the intrinsic viscosity is 1.37 dL / g.

[0086] PBAT Resin 5#: Self-made. The preparation method is basically the same as that of PBAT Resin 1#, except that in step 3), after obtaining the prepolymer, it is further polymerized for 1.5 h under the conditions of a temperature of 200 °C and a pressure of 120 Pa. Finally, PBAT Resin 5# is obtained, with a T content of 48 mol%; the intrinsic viscosity is 0.9 dL / g.

[0087] PBAT Resin 6#: Self-made. The preparation method is basically the same as that of PBAT Resin 1#, except that in step 3), after obtaining the prepolymer, it is further polymerized for 3.5 h under the conditions of a temperature of 200 °C and a pressure of 120 Pa. Finally, PBAT Resin 6# is obtained, with a T content of 48 mol%; the intrinsic viscosity is 1.5 dL / g.

[0088] PBAT Resin 7#: Self-made. The preparation method is basically the same as that of PBAT Resin 1#, except that in step 3), the T content is adjusted by adjusting the mass flow ratio of A1 and A2. Finally, PBAT Resin 7# is obtained, with a T content of 42 mol%; the intrinsic viscosity is 1.36 dL / g.

[0089] PBAT Resin 8#: Self-made. The preparation method is basically the same as that of PBAT Resin 1#, except that in step 3), the T content is adjusted by adjusting the mass flow ratio of A1 and A2. Finally, PBAT Resin 8# is obtained, with a T content of 53.5 mol%; the intrinsic viscosity is 1.36 dL / g.

[0090] Polyester 1#: Self-made. The preparation method is as follows:

[0091] 1) Add terephthalic acid and 1,4-butanediol to the esterification reactor according to the molar ratio of 1:1.2, and add 1% of the total mass of the raw materials of tetrabutyl titanate as a catalyst. React at a temperature of 240 °C and a pressure of 40 KPa for 2.5 h to obtain esterified product A1;

[0092] 2) Add adipic acid and 1,4-butanediol to the esterification reactor in a molar ratio of 1:1.3, and react for 2.5 h under the conditions of a temperature of 200 °C and a pressure of 40 KPa to obtain esterified product A2;

[0093] 3) Continuously feed the two esterified products A1 and A2 into a mixer for mixing, react for 2.5 h under the conditions of a temperature of 240 °C and a pressure of 4 KPa to obtain a prepolymer, and then continue to polymerize for 2.5 h under the conditions of a temperature of 200 °C and a pressure of 120 Pa to obtain polyester 1#. The T content is 70 mol%; the intrinsic viscosity is 1.39 dL / g.

[0094] Polyester 2#: Self-made, the preparation method is basically the same as that of polyester 1#, the difference is that in step 3), the T content is adjusted by adjusting the mass flow ratio of A1 and A2, and finally polyester 2# is obtained, with a T content of 55 mol%; the intrinsic viscosity is 1.38 dL / g.

[0095] Polyester 3#: Self-made, the preparation method is basically the same as that of polyester 1#, the difference is that in step 3), the T content is adjusted by adjusting the mass flow ratio of A1 and A2, and finally polyester 3# is obtained, with a T content of 80 mol%; the intrinsic viscosity is 1.37 dL / g.

[0096] Polyester 4#: Self-made, the preparation method is basically the same as that of polyester 1#, the difference is that in step 3), after obtaining the prepolymer, continue to polymerize for 3.5 h under the conditions of a temperature of 200 °C and a pressure of 120 Pa, and finally obtain polyester 4#, with a T content of 70 mol%; the intrinsic viscosity is 1.50 dL / g.

[0097] Polyester 5#: Self-made, the preparation method is basically the same as that of polyester 1#, the difference is that in step 2), adipic acid is replaced by sebacic acid, and finally polyester 5# is obtained, with a T content of 70 mol%; the intrinsic viscosity is 1.38 dL / g.

[0098] Polyester 6#: Self-made, the preparation method is basically the same as that of polyester 1#, the difference is that in step 3), the mass flow ratio of A1 and A2 is adjusted, and finally polyester 6# is obtained, with a T content of 65 mol%; the intrinsic viscosity is 1.38 dL / g.

[0099] Filler 1#: Calcium carbonate, commercially available, D50 particle size is 5 μm;

[0100] Filler 2#: Calcium carbonate, commercially available, D50 particle size is 10 μm;

[0101] Other additive 1#: Composed of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:1, both antioxidant 1010 and antioxidant 168 are commercially available.

[0102] Unless otherwise specified, the components (such as other additives) selected in each parallel example and comparative example are the same commercially available products.

[0103] The PBAT composites provided in each example and comparative example of the present invention were subjected to performance determination according to the following test methods:

[0104] Blown film opening grade: The PBAT composite was put into a conventional blown film machine, the blown film thickness was 25 μm, the production capacity was 50 kg / h, and the blown film bag type was 25*(12.5±3.5) to obtain a film sample, and then the film sample was evaluated.

[0105] Level Level description K1 Naturally open, all bags can be opened by gently shaking K2 Can be opened by rubbing with hands, all bags can be opened by shaking forcefully K3 The bellows cannot be opened naturally and can be easily torn K4 The bag cannot be opened normally and can be torn. The bag remains unchanged after being torn K5 The bag cannot be opened normally and is severely deformed after being torn

[0106] Printing performance: Characterized by the dyne value. The larger the dyne value, the better the ink adhesion performance of the material, that is, the better the printing performance. In the order of the calibration values of the dyne pens from small to large, the dyne pens were gently touched perpendicular to the test surface respectively, and then quickly moved across the surface, and the maximum marked value corresponding to the dyne pen that maintained the result A was recorded as the dyne value of the sample. The result A was that the ink of the dyne pen uniformly and continuously wetted the entire surface without forming breaks or stagnation.

[0107] Degradation performance: The biodegradation rate was tested according to the industrial composting conditions under the compostable conditions in GB / T 41010-2021.

[0108] The PBAT composites of the examples and comparative examples of the present invention were prepared by the following preparation method:

[0109] Weigh each component according to the formula, mix each component evenly, and then put it into a twin-screw extruder, and extrude and granulate at 150-240 °C to obtain a PBAT composite.

[0110] Examples 1-19

[0111] Examples 1-19 provided a series of PBAT composites, and their formulas are shown in Table 1 and Table 2.

[0112] Table 1 Formulas of Examples 1-9 (parts by weight)

[0113]

[0114] Table 2 Formulas of Examples 10-19 (parts by weight)

[0115]

[0116]

[0117] Comparative Examples 1-7

[0118] Comparative Examples 1 to 7 provide a series of PBAT composites, and their formulations are shown in Table 3.

[0119] Table 3 Formulations of Comparative Examples 1 to 7 (parts by weight)

[0120]

[0121] The properties of the PBAT composites of each example and comparative example were determined according to the above-mentioned test methods, and the test results are shown in Table 4.

[0122] Table 4 Test Results of the Properties of the PBAT Composites of Each Example and Comparative Example

[0123]

[0124]

[0125]

[0126] As can be seen from Table 4:

[0127] The film blowing opening grades of the PBAT composites of Examples 1 to 19 are all K1 or K2, the dyne values are all above 34, and the degradation performance is all above 80%, indicating that the PBAT composites of the present invention maintain good degradation performance, while taking into account good film blowing opening performance and printing performance.

[0128] In Comparative Example 1, the T content of the added PBAT resin is too low, the film blowing opening performance of the PBAT composite is poor, the dyne value is low, and the printing performance is poor. In Comparative Example 2, the T contents of the selected polyester and the PBAT composite are both above 52 mol%, and the film blowing opening performance of the PBAT composite is poor; and the degradation performance is poor, unable to meet its conventional application requirements. In Comparative Example 3, no polyester is added, and the film blowing opening performance of the PBAT composite is poor. In Comparative Example 4, no PBAT resin is added, but it is replaced with an equal amount of Polyester 1#, which is equivalent to that the added PBAT resin in Comparative Example 4 has a T content of 70%, and the printing performance of the PBAT composite is poor; the degradation performance is also poor, unable to meet its conventional application requirements. In Comparative Example 5, PBAT Resin 8# is added, and the film blowing opening performance and printing performance of the PBAT composite are poor. In Comparative Example 6, the dosage of the polyester is too much, and the printing performance of the PBAT composite is poor; the degradation performance is also poor, unable to meet its conventional application requirements. In Comparative Example 7, no polylactic acid is added, and the printing performance of the PBAT composite is poor.

[0129] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A PBAT composite material, characterized in that, Comprising the following components in parts by weight: In the PBAT resin, the proportion of terephthalic acid-derived units relative to all dicarboxylic acid-derived units is 44-52 mol%; In the polyester, the dicarboxylic acid-derived unit is derived from terephthalic acid and an aliphatic dicarboxylic acid having C 4～10 , and the proportion of the terephthalic acid-derived unit relative to all the dicarboxylic acid-derived units is 55 to 80 mol%, and the diol-derived unit is derived from butanediol.

2. The PBAT composite material according to claim 1, wherein The melt mass flow rate of the polylactic acid measured under the conditions of 2.16 kg and 190 °C is 1-10 g / 10 min.

3. The PBAT composite material according to claim 1, wherein The intrinsic viscosity of the PBAT resin is 0.9 dL / g to 1.5 dL / g.

4. The PBAT composite material according to claim 1, wherein The filler is at least one of calcium carbonate, talc, kaolin, mica powder or montmorillonite.

5. The PBAT composite material according to claim 1, wherein The D50 particle size of the filler is ≤10 μm.

6. The PBAT composite material according to claim 1, wherein The PBAT composite material further comprises 0.2-2 parts of other additives.

7. The PBAT composite material according to claim 6, wherein The processing aid is at least one of an antioxidant, a stabilizer, an antistatic agent, an antifogging agent, a UV absorber or a UV stabilizer.

8. The PBAT composite material according to claim 1, wherein The PBAT composite material comprises the following components in parts by weight:

9. The preparation method of the PBAT composite material according to any one of claims 1 to 8, characterized in that, Comprising the following steps: mixing the components, melt-extruding, and pelletizing to obtain the PBAT composite material.

10. Use of the PBAT composite material according to any one of claims 1-8 in the preparation of film products.

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