Modified PBAT / nylon 66 composite material and preparation method thereof

Abstract

The invention discloses a modified PBAT / nylon 66 composite material and a preparation method thereof, and relates to the technical field of plastic materials. Nylon 66; a compatible modifier; an antioxidant; a lubricant; the compatibility modifier is prepared by the following steps: dissolving hydroxyl-terminated hyperbranched polyester in a solvent, adding lactam and adipic acid, uniformly stirring, heating to 120 DEG C, reacting until the acid value is 38-42 mgKOH / g, cooling to 70 DEG C, adding polyethylene glycol, uniformly stirring, heating to 75 DEG C, dropwise adding a mixed solution of a coupling agent and a catalyst within 2 hours, keeping stirring, and cooling to room temperature to obtain the compatibility modifier. Then heating to 85 DEG C, completely reacting, removing the solvent, precipitating, washing and drying to obtain a compatible modifier; according to the compatible modifier, a tough and firm interface transition layer is constructed between two incompatible phases, so that the pull-out of nylon 66 microfibers and the generation of PBAT interface holes in the in-situ microfiber process of PBAT and nylon 66 are fundamentally inhibited.

Description

Technical Field

[0001] This invention relates to the field of plastic materials technology, specifically to a modified PBAT / nylon 66 composite material and its preparation method. Background Technology

[0002] Polybutylene adipate terephthalate (PBAT), a fully biodegradable aliphatic-aromatic copolyester, possesses excellent flexibility, ductility, and processability, showing broad application prospects in packaging films, agricultural films, and disposable products. However, PBAT's inherent low strength, low modulus, and poor heat distortion temperature severely limit its application in more applications requiring high structural integrity or weather resistance. Therefore, reinforcing and modifying PBAT to broaden its application range has become one of the current research hotspots in the field of biodegradable materials.

[0003] Blending high-strength, high-modulus engineering plastics with PBAT is an effective way to achieve reinforcement modification. Nylon 66 (PA66), as a typical semi-crystalline engineering plastic, possesses excellent mechanical properties and heat resistance, and is considered an ideal candidate material for the reinforcing phase. Theoretically, by melt blending PA66 into a fibrous or microfiber morphology within the PBAT matrix, it is hoped that biomimetic composite structures can be constructed, thereby significantly improving the overall performance of the composite material.

[0004] However, PBAT and PA66 differ significantly in molecular structure, polarity, and crystallization behavior, leading to thermodynamic incompatibility. Direct blending results in extremely weak interphase adhesion, making it difficult for PA66 to disperse well within the PBAT matrix, and even more difficult to stably form a microfiber structure with effective reinforcing properties during processing. This typically leads to severe phase separation in the composite material, with the interface becoming a stress concentration point and crack initiation site, ultimately causing a decrease in the material's mechanical properties, particularly toughness and strength.

[0005] To overcome this bottleneck, researchers have tried various methods. For example, the "in-situ microfibrillation" technique is used, which involves stretching the dispersed PA66 phase into microfibers in situ during processing using a specific extrusion stretching process. Related studies (such as the article "Performance of PBAT / PA6 In-situ Microfibrillated Composites") have confirmed that this method can successfully prepare PA6 microfibers in the PBAT matrix and improve the yield strength and modulus of the composite to some extent. However, the article also clearly points out that because the compatibility between the two phases has not been fundamentally improved, the interface between the PA6 microfibers and the PBAT matrix is ​​clear, and the microfibers are easily pulled out under stress, leaving a large number of pores in the cross-section. This results in limited improvement in the tensile strength, elongation at break, and impact toughness of the composite under high strain, and even a performance decline when the reinforcing phase content is high, with the stress-strain curve exhibiting unstable sawtooth fluctuations. This phenomenon profoundly reveals that simply relying on physical morphology control (in-situ fiber formation) while ignoring the strengthening of interfacial chemical and physical interactions cannot fully realize the potential of the reinforcing phase. Weak interfaces remain a key scientific and technological problem restricting the performance improvement of such composites.

[0006] For interfacial modification, conventional methods involve adding compatibilizers such as maleic anhydride graft copolymers. While these compatibilizers can improve interfacial adhesion to some extent, their effect is limited, often sacrificing toughness while increasing strength. Furthermore, for dynamic processes like in-situ fiber formation involving complex rheological and morphological evolution, their interfacial modification efficiency and stability are insufficient. Developing a novel compatibilizer that can actively adapt to the in-situ microfibrillation process and construct a strong and stable interfacial layer between incompatible phases is crucial for preparing high-performance PBAT / PA66 composites. Summary of the Invention

[0007] The present invention aims to solve the problem that the mechanical properties of existing PBAT / Nylon 66 composite materials are difficult to improve effectively due to poor compatibility.

[0008] To address the aforementioned problems, this invention provides a modified PBAT / Nylon 66 composite material, characterized by comprising the following components in parts by weight: 100 parts of PBAT; 4-16 parts of Nylon 66; 2-5 parts of a compatibility modifier; 0.2-0.4 parts of an antioxidant; and 0.4-0.6 parts of a lubricant. The compatibility modifier is prepared through the following steps: S1. Dissolve the hydroxyl-terminated hyperbranched polyester in a solvent, add lactam and adipic acid, stir until homogeneous, heat to 120℃ and react until the acid value is 38-42 mgKOH / g to obtain the prepolymer; S2. Cool the prepolymer to 70°C, add polyethylene glycol and stir until homogeneous, raise the temperature to 75°C, add the mixture of coupling agent and catalyst dropwise over 2 hours while stirring, and then raise the temperature to 85°C until the reaction is complete to obtain the polymer. S3. Remove the solvent from the polymer, precipitate, wash and dry to obtain a compatibility modifier.

[0009] The modified PBAT / Nylon 66 composite material provided by this invention has, but is not limited to, the following beneficial effects compared to the prior art: The modified PBAT / Nylon 66 composite material of this invention introduces a compatibility modifier. Its molecular structure is based on a terminal hydroxyl hyperbranched polyester, grafted with rigid groups formed by lactam / adipic acid and flexible compatibility groups of polyethylene glycol, and chemically bonded by a coupling agent. This compatibility modifier can spontaneously migrate and accumulate at the interface between PBAT and Nylon 66. Its rigid groups anchor the Nylon 66 phase through strong interactions such as amide bonds and hydrogen bonds, while its flexible compatibility groups are compatible with the ester groups of PBAT and undergo chain segment entanglement. This rigid-flexible bridging structure constructs a strong and robust interfacial transition layer between the two incompatible phases, fundamentally inhibiting the pull-out of Nylon 66 microfibers and the formation of pores at the PBAT interface during the in-situ microfiber formation process of PBAT and Nylon 66.

[0010] Based on this, the reinforcing potential of Nylon 66 is fully utilized, and the yield strength, tensile modulus, and tensile strength of PBAT / Nylon 66 composites are significantly improved. The strong interface can effectively prevent crack propagation, so that the composite can maintain or even improve its impact toughness and elongation at break while maintaining high strength, avoiding the drawbacks of embrittlement caused by traditional reinforcement. Moreover, the compatibility modifier can act as a heterogeneous nucleating agent to promote PBAT crystallization, thereby increasing the heat distortion temperature of PBAT / Nylon 66 composites and broadening their application temperature range. At the same time, the addition of the compatibility modifier reduces the melt viscosity and improves the processing fluidity of the composite, making it more stable during extrusion and stretching.

[0011] Further, in S1, the mass ratio of the terminal hydroxyl hyperbranched polyester to the solvent is 1:(1.5-2), and the solvent is N-methylpyrrolidone (NMP).

[0012] Specifically, this ratio ensures that the reaction system has the optimal solution concentration and fluidity; when the mass ratio is 1:1.5, the system concentration is higher and the reaction efficiency is higher, but the viscosity is slightly higher and the stirring requirements are higher; when the mass ratio is 1:2, the system is more dilute, the mass and heat transfer is better, and the reaction is more uniform and controllable; NMP, as a high-boiling-point, strongly polar aprotic solvent, can effectively dissolve all reactants (especially hyperbranched polyesters and prepolymers) and provide a stable reaction environment, preventing local gelation and ensuring the uniformity and reproducibility of the synthesis reaction.

[0013] Further, in S1, the mass ratio of the terminal hydroxyl hyperbranched polyester, lactam, and adipic acid is 100:(30-40):(15-20).

[0014] Specifically, this ratio is the core of controlling the rigid groups in the compatibility modifier molecule; the lactam provides the basis for forming PA6-like structural units, and adipic acid, as the end-capping agent and linking unit, precisely controls the length of the oligoamide segments and the number of terminal carboxyl groups; this ratio ensures that the generated prepolymer has a sufficient number of PA6-like segments to provide strong binding force with nylon 66, and also provides an appropriate amount of terminal carboxyl groups (introduced by adipic acid) to provide sufficient active sites for the next coupling reaction with polyethylene glycol.

[0015] Furthermore, in S2, the mass ratio of the terminal hydroxyl hyperbranched polyester to polyethylene glycol (PEG) is 20:9.

[0016] Specifically, this ratio precisely controls the number of flexible compatible groups grafted onto the hyperbranched core, resulting in excellent compatibility between the PEG segments and the PBAT matrix. This ratio design ensures that the modifier molecules have an appropriate hydrophilic-lipophilic balance and spatial conformation, guaranteeing that the compatibility modifier can be effectively positioned at the interface during melt blending, and that its flexible compatible groups have sufficient length and number to embed into the PBAT phase to form a strong physical entanglement.

[0017] Furthermore, in S2, the coupling agent is isophorone diisocyanate (IPDI), and the catalyst is dibutyltin dilaurate (DBTDL).

[0018] Specifically, IPDI is an aliphatic diisocyanate with steric hindrance. The two -NCO groups have different reactivity, which makes the coupling reaction more controllable and stable, effectively avoiding gelation caused by excessively rapid reaction. Its product (carbamate / urea bond) has good heat resistance and hydrolysis resistance, ensuring the structural stability of the modifier. DBTDL is a highly efficient and specific catalyst for the reaction of isocyanate and hydroxyl group, which can significantly accelerate the reaction rate, allowing the coupling reaction to proceed quickly and completely at a lower temperature, avoiding side reactions (such as ester bond hydrolysis) that may be caused by prolonged high temperature, and ensuring the uniformity of product quality.

[0019] Further, in S2, the amount of the coupling agent is 15 wt% of the amount of the terminal hydroxyl hyperbranched polyester, and the amount of the catalyst is 0.15 wt% of the amount of the terminal hydroxyl hyperbranched polyester.

[0020] Specifically, at this dosage, the coupling agent is designed to ensure that it can fully couple the terminal carboxyl / hydroxyl groups of the prepolymer with the hydroxyl groups of PEG, achieving effective chemical bonding between the rigid and flexible arms and forming a stable "core-shell-arm" structure. Insufficient dosage will lead to incomplete connection, while excessive dosage will produce unreacted -NCO, which will bring instability. At this dosage, the catalyst can ensure efficient reaction while avoiding the potential negative impact of excessive catalyst residue on subsequent composite material processing (such as thermal stability).

[0021] Furthermore, in S2, the criterion for determining whether the reaction is complete is: sampling and monitoring at 2260-2270 cm⁻¹ using FT-IR (Fourier Transform Infrared Spectroscopy). -1 The intensity of the -NCO characteristic peak is measured, and the reaction endpoint is reached when the -NCO characteristic peak completely disappears.

[0022] Specifically, this standard provides accurate, reliable, and non-destructive criteria for the endpoint of chemical reactions, utilizing FT-IR real-time monitoring at 2260-2270 cm⁻¹. -1 The intensity of the characteristic absorption peak of the isocyanate group (-NCO) can be used to prove that IPDI has reacted completely when it disappears completely. This avoids the vague judgment that relies on time or experience in the past, and ensures that each batch of synthesized modifier has a consistent and expected chemical structure, thereby ensuring the stability and reproducibility of its interface modification effect, which is the key to product quality control.

[0023] Furthermore, in S3, the method for removing the solvent from the polymer is as follows: the polymer is rotary evaporated at 80°C and a vacuum of -0.098 MPa for 1 hour.

[0024] Specifically, these conditions enable efficient and thorough removal of the high-boiling-point solvent NMP at relatively low temperatures. The temperature control at 80℃ ensures rapid solvent evaporation while remaining far below the temperature at which the product may undergo thermal degradation and the boiling point of the solvent. This avoids side reactions such as molecular chain breakage or cross-linking caused by prolonged high-temperature treatment, thereby protecting the chemical structure and performance of the compatibility modifier.

[0025] This invention also discloses a preparation method for preparing the modified PBAT / nylon 66 composite material as described above, comprising the following steps: Step 1: Prepare the raw material components according to the weight ratio; Step 2: Premix a portion of PBAT with all of the compatibility modifier and then melt-granulate to obtain active masterbatch; Step 3: Mix the remaining raw material components with the active masterbatch evenly, and then use a co-rotating twin-screw extruder equipped with a multi-stage stretching die to melt-blend, stretch, and extrude sheets to obtain modified PBAT / Nylon 66 composite material.

[0026] The preparation method of the modified PBAT / Nylon 66 composite material of the present invention has, but is not limited to, the following beneficial effects compared with the prior art: This preparation method first involves combining a compatibility modifier with a portion of PBAT to form a high-concentration active masterbatch. This ensures that trace amounts of crucial modifiers are pre-dispersed and pre-compatible within the PBAT. Subsequently, during final blending, this active masterbatch distributes more rapidly and uniformly throughout the system, facilitating the efficient migration of the compatibility modifier to the interface in the molten state. Combined with a co-rotating twin-screw extruder equipped with a multi-stage stretching die, this method not only achieves in-situ microfibrillation of nylon 66 but also simultaneously enables efficient interfacial compatibility enhancement through the active masterbatch technology, and is easily scalable for industrial application.

[0027] Furthermore, in step two, the mass ratio of PBAT to the compatibility modifier is 1:1.

[0028] Specifically, the 1:1 mass ratio is the golden ratio for preparing high-concentration active masterbatch. It ensures that the compatibility modifier has a sufficiently high concentration in the masterbatch to fulfill its function, while also guaranteeing a sufficient amount of PBAT as a carrier to facilitate the melt granulation process. The active masterbatch has good particle strength and flowability, which is convenient for subsequent metering, transportation and mixing. Moreover, when the active masterbatch is finally blended, this ratio can quickly release a sufficient amount of modifier without being overly diluted due to excessive carrier resin. Detailed Implementation

[0029] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0030] The terminology used in the embodiments of this application is for the purpose of describing particular implementations only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the implementations of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0031] It should be understood that in the various embodiments of this application, the sequence number of each process does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the implementation regulations of this application.

[0032] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass described in the embodiments of this application can be a mass unit known in the chemical industry, such as μg, mg, g, or kg.

[0033] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0034] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application are available on the market or can be prepared by existing methods.

[0035] Preparation Example 1

[0036] The compatibility modifier is prepared by following these steps in sequence: S1. Dissolve 100g of hydroxyl-terminated hyperbranched polyester in 200g of NMP, add 35g of lactam and 18g of adipic acid and stir until homogeneous. Heat to 120℃ and react until the acid value is 40mgKOH / g to obtain the prepolymer. S2. Cool the prepolymer to 70℃, add 45g of polyethylene glycol and stir until homogeneous. Raise the temperature to 75℃, and over 2 hours, dropwise add a mixture of 15g IPDI and 0.15g DBTDL while maintaining stirring. Then raise the temperature to 85℃ and react for 1.5 hours. Subsequently, take samples every 20 minutes and monitor the 23265cm² area using FT-IR. -1 The intensity of the -NCO characteristic peak is measured, and the reaction endpoint is reached when the -NCO characteristic peak completely disappears; the polymer is obtained. S3. The polymer was rotary evaporated at 80℃ and -0.098MPa vacuum for 1 hour, then precipitated, washed and dried to obtain the compatibility modifier.

[0037] Preparation Example 2

[0038] The compatibility modifier is prepared by following these steps in sequence: S1. Dissolve 100g of hydroxyl-terminated hyperbranched polyester in 200g of NMP, add 30g of lactam and 15g of adipic acid and stir until homogeneous. Heat to 120℃ and react until the acid value is 40mgKOH / g to obtain the prepolymer. S2. Cool the prepolymer to 70℃, add 45g of polyethylene glycol and stir until homogeneous. Raise the temperature to 75℃, and over 2 hours, dropwise add a mixture of 15g IPDI and 0.15g DBTDL while maintaining stirring. Then raise the temperature to 85℃ and react for 1.5 hours. Subsequently, take samples every 20 minutes and monitor the 23265cm² area using FT-IR. -1 The intensity of the -NCO characteristic peak is measured, and the reaction endpoint is reached when the -NCO characteristic peak completely disappears; the polymer is obtained. S3. The polymer was rotary evaporated at 80℃ and -0.098MPa vacuum for 1 hour, then precipitated, washed and dried to obtain the compatibility modifier.

[0039] Preparation Example 3

[0040] The compatibility modifier is prepared by following these steps in sequence: S1. Dissolve 100g of hydroxyl-terminated hyperbranched polyester in 200g of NMP, add 40g of lactam and 20g of adipic acid, stir until homogeneous, heat to 120℃ and react until the acid value is 40mgKOH / g to obtain the prepolymer. S2. Cool the prepolymer to 70℃, add 45g of polyethylene glycol and stir until homogeneous. Raise the temperature to 75℃, and over 2 hours, dropwise add a mixture of 15g IPDI and 0.15g DBTDL while maintaining stirring. Then raise the temperature to 85℃ and react for 1.5 hours. Subsequently, take samples every 20 minutes and monitor the 23265cm² area using FT-IR. -1 The intensity of the -NCO characteristic peak is measured, and the reaction endpoint is reached when the -NCO characteristic peak completely disappears; the polymer is obtained. S3. The polymer was rotary evaporated at 80℃ and -0.098MPa vacuum for 1 hour, then precipitated, washed and dried to obtain the compatibility modifier.

[0041] Example 1

[0042] This embodiment discloses a modified PBAT / Nylon 66 composite material, which is prepared according to the following steps: Step 1: Prepare 100 parts by weight of PBAT; 10 parts of nylon 66; 3 parts of the compatibility modifier of Preparation Example 1; 0.3 parts of antioxidant 1010; and 0.5 parts of calcium stearate. Step 2: Premix 3 parts of PBAT with all the compatibility modifiers and then melt granulate to obtain active masterbatch; Step 3: Mix the remaining raw material components with the active masterbatch evenly, and then use a co-rotating twin-screw extruder equipped with a multi-stage stretching die to melt-blend, stretch, and extrude sheets to obtain modified PBAT / Nylon 66 composite material.

[0043] Example 2

[0044] This embodiment discloses a modified PBAT / Nylon 66 composite material, which is prepared according to the following steps: Step 1: Prepare 100 parts by weight of PBAT; 4 parts of nylon 66; 2 parts of the compatibility modifier of Preparation Example 1; 0.2 parts of antioxidant 1010; and 0.4 parts of calcium stearate. Step 2: Premix 2 parts of PBAT with all the compatibility modifier, then melt granulate to obtain active masterbatch; Step 3: Mix the remaining raw material components with the active masterbatch evenly, and then use a co-rotating twin-screw extruder equipped with a multi-stage stretching die to melt-blend, stretch, and extrude sheets to obtain modified PBAT / Nylon 66 composite material.

[0045] Example 3

[0046] This embodiment discloses a modified PBAT / Nylon 66 composite material, which is prepared according to the following steps: Step 1: Prepare 100 parts by weight of PBAT; 16 parts of nylon 66; 5 parts of the compatibility modifier of Preparation Example 1; 0.4 parts of antioxidant 1010; and 0.6 parts of calcium stearate. Step 2: Premix 16 parts of PBAT with all the compatibility modifiers and then melt granulate to obtain active masterbatch; Step 3: Mix the remaining raw material components with the active masterbatch evenly, and then use a co-rotating twin-screw extruder equipped with a multi-stage stretching die to melt-blend, stretch, and extrude sheets to obtain modified PBAT / Nylon 66 composite material.

[0047] Example 4

[0048] Compared with Example 1, the only difference is that the compatibility modifier in Preparation Example 1 is replaced with the compatibility modifier in Preparation Example 2, while the other steps and conditions remain the same, and the modified PBAT / Nylon 66 composite material is finally obtained.

[0049] Example 5

[0050] Compared with Example 1, the only difference is that the compatibility modifier in Preparation Example 1 is replaced with the compatibility modifier in Preparation Example 3, while the other steps and conditions remain the same, and the modified PBAT / Nylon 66 composite material is finally obtained.

[0051] Comparative Example 1

[0052] This comparative example discloses a modified PBAT / nylon 66 composite material, which was prepared according to the following steps: Step 1: Prepare 100 parts PBAT, 10 parts Nylon 66, 0.3 parts antioxidant 1010, and 0.5 parts calcium stearate according to the following weight ratios; Step 2: Mix all raw material components evenly, and then use a co-rotating twin-screw extruder equipped with a multi-stage stretching die to melt-blend, stretch, and extrude sheets to obtain PBAT / Nylon 66 composite material.

[0053] Comparative Example 2

[0054] This comparative example discloses a modified PBAT / nylon 66 composite material, which was prepared according to the following steps: Step 1: Prepare 100 parts by weight of PBAT; 10 parts of nylon 66; 3 parts of the compatibility modifier of Preparation Example 1; 0.3 parts of antioxidant 1010; and 0.5 parts of calcium stearate. Step 2: Mix all raw material components evenly, and then use a co-rotating twin-screw extruder equipped with a multi-stage stretching die to melt-blend, stretch, and extrude sheets to obtain PBAT / Nylon 66 composite material.

[0055] The performance of the PBAT / Nylon 66 composite materials prepared in Examples 1-5 and Comparative Examples 1-2 was tested. The specific test items and methods are as follows: Tensile properties: Referring to GB / T 1040.3-2006, a universal testing machine was used to cut PBAT / Nylon 66 composite sheets into standard dumbbell-shaped strips at a tensile speed of 50 mm / min; Impact performance: Referring to GB / T 1843-2008, a cantilever beam impact testing machine was used to prepare PBAT / Nylon 66 composite materials with V-notches. Thermal properties: Differential scanning calorimetry was used to analyze the crystallization temperature (Tc, °C) and crystallinity (Xc, %) of the PBAT components.

[0056] The test results are listed in Table 1, as follows: Table 1

[0057] Analysis of the data in Table 1 shows that, compared with Comparative Examples 1-2, the modified PBAT / Nylon 66 composite materials of Examples 1-5 have significantly better mechanical and thermal properties.

[0058] Specifically, compared to Examples 1-5, the mechanical and thermal properties of Comparative Example 1, which did not contain a compatibilizer, decreased significantly. This indicates that adding a compatibilizer can improve the mechanical and thermal properties of the PBAT / Nylon 66 composite material. This may be because the molecular structure of the compatibilizer is based on a terminal hydroxyl hyperbranched polyester, grafted with rigid groups formed by lactam / adipic acid and flexible compatibilizing groups of polyethylene glycol. Through chemical bonding with a coupling agent, it can spontaneously migrate and accumulate at the interface between the two phases of PBAT and Nylon 66. Its rigid groups anchor the Nylon 66 phase through strong interactions such as amide bonds and hydrogen bonds, while its flexible compatibilizing groups are compatible with the ester groups of PBAT and undergo chain segment entanglement. This rigid-flexible bridging structure constructs a strong and robust interfacial transition layer between the two incompatible phases, fundamentally inhibiting the pull-out of Nylon 66 microfibers and the formation of pores at the PBAT interface during the in-situ microfiber formation process of PBAT and Nylon 66.

[0059] Compared to Examples 1-5, Comparative Example 2, which uses a one-time mixing and melting method for in-situ fiber formation, showed a decrease in mechanical and thermal properties. This indicates that the distributed mixing and melting method used in this invention for in-situ fiber formation is beneficial for improving the mechanical and thermal properties of the PBAT / Nylon 66 composite material. This may be because: firstly, the compatibility modifier and a portion of PBAT are prepared into a high-concentration active masterbatch, which ensures that trace but critical modifiers can be pre-dispersed and pre-compatible in PBAT; subsequently, during the final blending, this active masterbatch can be distributed more quickly and uniformly in the system, which is beneficial for the efficient migration of the compatibility modifier to the interface in the molten state.

[0060] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A modified PBAT / Nylon 66 composite material, characterized in that, It comprises the following components in parts by weight: 100 parts PBAT; 4-16 parts Nylon 66; 2-5 parts compatibility modifier; 0.2-0.4 parts antioxidant; 0.4-0.6 parts lubricant; The compatibility modifier is prepared through the following steps: S1. Dissolve the hydroxyl-terminated hyperbranched polyester in a solvent, add lactam and adipic acid, stir until homogeneous, heat to 120℃ and react until the acid value is 38-42 mgKOH / g to obtain the prepolymer; S2. Cool the prepolymer to 70°C, add polyethylene glycol and stir until homogeneous, raise the temperature to 75°C, add the mixture of coupling agent and catalyst dropwise over 2 hours while stirring, and then raise the temperature to 85°C until the reaction is complete to obtain the polymer. S3. Remove the solvent from the polymer, precipitate, wash and dry to obtain a compatibility modifier.

2. The modified PBAT / Nylon 66 composite material according to claim 1, characterized in that, In S1, the mass ratio of the terminal hydroxyl hyperbranched polyester to the solvent is 1:(1.5-2), and the solvent is N-methylpyrrolidone.

3. The modified PBAT / Nylon 66 composite material according to claim 1, characterized in that, In S1, the mass ratio of the terminal hydroxyl hyperbranched polyester, lactam, and adipic acid is 100:(30-40):(15-20).

4. The modified PBAT / Nylon 66 composite material according to claim 1, characterized in that, In S2, the mass ratio of the hydroxyl-terminated hyperbranched polyester to polyethylene glycol is 20:

9.

5. The modified PBAT / Nylon 66 composite material according to claim 1, characterized in that, In S2, the coupling agent is isophorone diisocyanate, and the catalyst is dibutyltin dilaurate.

6. The modified PBAT / Nylon 66 composite material according to claim 1, characterized in that, In S2, the amount of the coupling agent is 15 wt% of the amount of the terminal hydroxyl hyperbranched polyester, and the amount of the catalyst is 0.15 wt% of the amount of the terminal hydroxyl hyperbranched polyester.

7. The modified PBAT / Nylon 66 composite material according to claim 1, characterized in that, In S2, the criterion for determining whether the reaction is complete is: sampling, and monitoring at 2260-2270 cm⁻¹ using FT-IR. -1 The intensity of the -NCO characteristic peak is measured, and the reaction endpoint is reached when the -NCO characteristic peak completely disappears.

8. The modified PBAT / Nylon 66 composite material according to claim 1, characterized in that, In S3, the method for removing the solvent from the polymer is to rotary evaporate the polymer at 80°C and a vacuum of -0.098 MPa for 1 hour.

9. A preparation method for preparing the modified PBAT / nylon 66 composite material as described in any one of claims 1-8, characterized in that, Includes the following steps: Step 1: Prepare the raw material components according to the weight ratio; Step 2: Premix a portion of PBAT with all of the compatibility modifier and then melt-granulate to obtain active masterbatch; Step 3: Mix the remaining raw material components with the active masterbatch evenly, and then use a co-rotating twin-screw extruder equipped with a multi-stage stretching die to melt-blend, stretch, and extrude sheets to obtain modified PBAT / Nylon 66 composite material.

10. The preparation method according to claim 9, characterized in that, In step two, the mass ratio of PBAT to the compatibility modifier is 1:1.

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