Anti-aging pbat composite material and preparation method and application thereof

Abstract

The application provides an anti-aging PBAT composite material and a preparation method and application thereof, and belongs to the technical field of biodegradable polymer materials.The composite material comprises the following raw materials in parts by mass: 80-99 parts of PBAT resin, 1-10 parts of eucommia extract, 0.5-5 parts of a compatilizer and 0-5 parts of an auxiliary agent;the application uses natural eucommia extract as an anti-aging agent, is green and environment-friendly, improves the interface bonding through a reactive compatilizer, effectively inhibits the thermal oxygen and light aging of the PBAT, has a long-lasting anti-aging effect, and meanwhile, the biodegradability of the material is maintained.

Description

Technical Field

[0001] This invention belongs to the field of biodegradable polymer materials technology, specifically relating to an anti-aging PBAT composite material, its preparation method, and its application. Background Technology

[0002] PBAT, a fully biodegradable polyester material, is widely used in packaging films, agricultural mulch films, and disposable tableware due to its good ductility and toughness. However, the PBAT molecular structure contains a large number of ester bonds, making it susceptible to degradation during processing, use, and storage due to factors such as heat, oxygen, and ultraviolet radiation. This degradation leads to molecular chain breakage, causing the material to rapidly become brittle, yellow, and experience a significant decline in mechanical properties. This drawback severely limits the lifespan of PBAT products, especially those requiring long-term outdoor exposure (such as agricultural mulch films).

[0003] Currently, to improve the anti-aging properties of PBAT, synthetic antioxidants and light stabilizers are commonly added, such as hindered phenols, phosphites, and hindered amines. While these synthetic auxiliaries are highly effective, they also present several problems: 1. Migration and precipitation: Some small-molecule auxiliaries easily migrate from the polymer matrix to the surface, resulting in poor durability of the anti-aging effect and potential contamination of contact materials. 2. Biocompatibility: For PBAT products that emphasize environmental protection and biodegradability, the addition of synthetic chemicals contradicts their "green" philosophy, especially in the agricultural and food packaging sectors, where their potential impact on soil and crops is concerning. 3. Cost: Highly effective synthetic anti-aging agents are expensive, increasing production costs.

[0004] Eucommia ulmoides is a traditional Chinese medicinal herb. Its bark and leaves are rich in various natural active ingredients, such as chlorogenic acid, aucubin, genipin, and flavonoids. These natural phenolic acids and glycosides have excellent antioxidant capabilities and can effectively scavenge free radicals. Currently, Eucommia ulmoides extracts are mainly used in the pharmaceutical, health food, and cosmetic fields, but its application as a natural anti-aging agent in biodegradable polyesters such as PBAT has not been publicly reported.

[0005] Therefore, developing a highly efficient, long-lasting, and environmentally friendly PBAT anti-aging technology based on natural extracts has significant practical implications and market value. Summary of the Invention

[0006] In view of the above-mentioned prior art, the present invention discloses an anti-aging PBAT composite material and its preparation method, so as to solve the technical problems of poor anti-aging effect and environmental unfriendliness of existing anti-aging PBAT products.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is to provide an anti-aging PBAT composite material, which comprises the following raw materials in parts by weight:

[0008] The mixture comprises 80-99 parts PBAT resin, 1-10 parts Eucommia ulmoides extract, 0.5-5 parts compatibilizer and 0-5 parts additives; the compatibilizer is one or more of PBAT-g-MAH, epoxy polymers or titanate coupling agents; the additives are one or more of lubricants, anti-hydrolysis agents or pigments; the Eucommia ulmoides extract is prepared by the following method: Eucommia ulmoides leaves or bark are extracted by hot reflux with an aqueous ethanol solution, and the extract is concentrated and dried to obtain the final product.

[0009] Based on the above technical solution, the present invention can be further improved as follows:

[0010] Furthermore, the epoxy polymer is a glycidyl methacrylate grafted polymer.

[0011] Furthermore, the lubricant is stearic acid or polyethylene wax; the anti-hydrolysis agent is carbodiimide.

[0012] Furthermore, the volume concentration of the ethanol-water solution is 50-75%; the particle size of the Eucommia ulmoides leaves or bark is 20-60 mesh; and the material-to-liquid ratio of the Eucommia ulmoides leaves or bark to the ethanol-water solution is 1g:8-15mL.

[0013] Furthermore, the hot reflux extraction temperature is 70~85℃, and the hot reflux extraction time is 1~3h.

[0014] Furthermore, the total content of chlorogenic acid and total flavonoids in the Eucommia ulmoides extract is >30%, and the moisture content is ≤5%.

[0015] This invention also discloses a method for preparing the above-mentioned anti-aging PBAT composite material, which includes the following steps:

[0016] S1: Vacuum dry PBAT resin at 70~80℃ for 4~8h, and dry Eucommia ulmoides extract at 50~60℃ for 2~4h;

[0017] S2: Add the dried PBAT resin, Eucommia ulmoides extract, compatibilizer and additives to a high-speed mixer in proportion, mix at room temperature for 5-15 minutes to obtain a premix;

[0018] S3: The premixed material is added to a twin-screw extruder, and after melt extrusion, cooling, traction, and pelletizing, it is obtained.

[0019] Based on the above technical solution, the present invention can be further improved as follows:

[0020] Furthermore, the processing temperature of the twin-screw extruder is set as follows: Zone 1 150~160℃, Zone 2 160~170℃, Zone 3 170~175℃, Zone 4 175~180℃, and the die head 175~180℃; the screw speed is 200~400rpm.

[0021] The present invention also discloses the application of the above-mentioned anti-aging PBAT composite material containing Eucommia ulmoides extract in the preparation of film products.

[0022] The beneficial effects of this invention are:

[0023] 1. Green and environmentally friendly: The natural plant Eucommia ulmoides extract replaces or partially replaces traditional synthetic anti-aging agents, making the composite material more biocompatible and environmentally friendly, meeting the requirements of sustainable development.

[0024] 2. Highly effective anti-aging: The active ingredients such as chlorogenic acid and flavonoids in Eucommia ulmoides extract are natural free radical scavengers and ultraviolet absorbers, which can effectively inhibit the thermo-oxidative aging and photo-aging of PBAT during processing and use, and significantly extend the service life of the products.

[0025] 3. Good compatibility and durability: By adding compatibilizers, the interfacial compatibility between the hydrophilic Eucommia ulmoides extract and the hydrophobic PBAT matrix is ​​improved, reducing the migration and precipitation of the extract and making the anti-aging effect more lasting.

[0026] 4. Simple process and controllable cost: The preparation method uses general plastic processing equipment, the process flow is simple, and it is easy to realize industrial production; Eucommia ulmoides is a renewable resource with wide availability, which helps to control costs.

[0027] 5. Maintaining biodegradability: While endowing PBAT with excellent anti-aging properties, this invention does not impair its inherent biodegradability. Detailed Implementation

[0028] The specific embodiments of the present invention will be described in detail below with reference to examples.

[0029] Example 1

[0030] An anti-aging PBAT composite material comprises the following raw materials in parts by weight: 93 parts PBAT resin, 4 parts Eucommia ulmoides extract and 3 parts PBAT-g-MAH (grafting rate 0.8%).

[0031] Eucommia ulmoides extract is prepared by the following method:

[0032] Five kilograms of dried Eucommia ulmoides leaves were pulverized and passed through a 40-mesh sieve. Then, 50 L of a 60% (v / v) ethanol aqueous solution was added, and the mixture was placed in a multi-functional extraction tank and refluxed at 80°C for 2 hours. The filtrate was collected by filtration. Another 40 L of 60% (v / v) ethanol was added to the residue, and extraction was performed under the same conditions for 1.5 hours. The two filtrates were combined, and the combined filtrate was concentrated under reduced pressure at 60°C and -0.08 MPa to a viscous paste (approximately 5 L). The concentrated paste was then spray-dried (inlet air temperature 175°C, outlet air temperature 85°C) to obtain 620 g of a brownish-yellow fine powder. HPLC analysis showed that the powder contained 19.2% chlorogenic acid, 25.7% total flavonoids (calculated as rutin), 44.9% total flavonoids, and 3.1% moisture.

[0033] The preparation method of anti-aging PBAT composite material includes the following steps:

[0034] S1: Vacuum dry PBAT resin at 80℃ for 8 hours, and dry Eucommia ulmoides extract at 60℃ for 4 hours.

[0035] S2: Add the dried PBAT resin, Eucommia ulmoides extract, and PBAT-g-MAH to a high-speed mixer in proportion and mix for 10 minutes at room temperature to obtain a premix.

[0036] S3: Add the premixed material to a twin-screw extruder (screw diameter 35mm, L / D=40) for melt blending. Set the processing temperature as follows: Zone 1 155℃, Zone 2 165℃, Zone 3 170℃, Zone 4 175℃, Die head 175℃, screw speed 300rpm. The extruded strip is then cooled with water, dried, and pelletized.

[0037] Example 2

[0038] An anti-aging PBAT composite material comprises the following raw materials in parts by weight: 90 parts PBAT resin, 6 parts Eucommia ulmoides extract and 4 parts PBAT-g-MAH (grafting rate 0.8%).

[0039] Eucommia ulmoides extract is prepared by the following method:

[0040] Five kilograms of dried Eucommia ulmoides leaves were pulverized and passed through a 40-mesh sieve. Then, 50 L of a 60% (v / v) ethanol aqueous solution was added, and the mixture was placed in a multi-functional extraction tank and refluxed at 80°C for 2 hours. The filtrate was collected by filtration. Another 40 L of 60% (v / v) ethanol was added to the residue, and extraction was performed under the same conditions for 1.5 hours. The two filtrates were combined, and the combined filtrate was concentrated under reduced pressure at 60°C and -0.08 MPa to a viscous paste (approximately 5 L). The concentrated paste was then spray-dried (inlet air temperature 175°C, outlet air temperature 85°C) to obtain 620 g of a brownish-yellow fine powder. HPLC analysis showed that the powder contained 19.2% chlorogenic acid, 25.7% total flavonoids (calculated as rutin), 44.9% total flavonoids, and 3.1% moisture.

[0041] The preparation method of anti-aging PBAT composite material includes the following steps:

[0042] S1: Vacuum dry PBAT resin at 80℃ for 8 hours, and dry Eucommia ulmoides extract at 60℃ for 4 hours.

[0043] S2: Add the dried PBAT resin, Eucommia ulmoides extract, and PBAT-g-MAH to a high-speed mixer in proportion and mix for 10 minutes at room temperature to obtain a premix.

[0044] S3: Add the premixed material to a twin-screw extruder (screw diameter 35mm, L / D=40) for melt blending. Set the processing temperature as follows: Zone 1 155℃, Zone 2 165℃, Zone 3 170℃, Zone 4 175℃, Die head 175℃, screw speed 300rpm. The extruded strip is then cooled with water, dried, and pelletized.

[0045] Example 3

[0046] An anti-aging PBAT composite material comprises the following raw materials in parts by weight: 96 parts PBAT resin, 2.5 parts Eucommia ulmoides extract and 1.5 parts PBAT-g-MAH (grafting rate 0.8%).

[0047] Eucommia ulmoides extract is prepared by the following method:

[0048] Five kilograms of dried Eucommia ulmoides leaves were pulverized and passed through a 40-mesh sieve. Then, 50 L of a 60% (v / v) ethanol aqueous solution was added, and the mixture was placed in a multi-functional extraction tank and refluxed at 80°C for 2 hours. The filtrate was collected by filtration. Another 40 L of 60% (v / v) ethanol was added to the residue, and extraction was performed under the same conditions for 1.5 hours. The two filtrates were combined, and the combined filtrate was concentrated under reduced pressure at 60°C and -0.08 MPa to a viscous paste (approximately 5 L). The concentrated paste was then spray-dried (inlet air temperature 175°C, outlet air temperature 85°C) to obtain 620 g of a brownish-yellow fine powder. HPLC analysis showed that the powder contained 19.2% chlorogenic acid, 25.7% total flavonoids (calculated as rutin), 44.9% total flavonoids, and 3.1% moisture.

[0049] The preparation method of anti-aging PBAT composite material includes the following steps:

[0050] S1: Vacuum dry PBAT resin at 80℃ for 8 hours, and dry Eucommia ulmoides extract at 60℃ for 4 hours.

[0051] S2: Add the dried PBAT resin, Eucommia ulmoides extract, and PBAT-g-MAH to a high-speed mixer in proportion and mix for 10 minutes at room temperature to obtain a premix.

[0052] S3: Add the premixed material to a twin-screw extruder (screw diameter 35mm, L / D=40) for melt blending. Set the processing temperature as follows: Zone 1 155℃, Zone 2 165℃, Zone 3 170℃, Zone 4 175℃, Die head 175℃, screw speed 300rpm. The extruded strip is then cooled with water, dried, and pelletized.

[0053] Example 4

[0054] An anti-aging PBAT composite material comprises the following raw materials in parts by weight: 99 parts PBAT resin, 10 parts Eucommia ulmoides extract, 5 parts PBAT-g-MAH (grafting rate 0.8%) and 4 parts carbodiimide.

[0055] Eucommia ulmoides extract is prepared by the following method:

[0056] Five kilograms of dried Eucommia ulmoides leaves were pulverized and passed through a 60-mesh sieve. Then, 75 L of a 75% (v / v) ethanol aqueous solution was added, and the mixture was placed in a multi-functional extraction tank and refluxed at 70°C for 1 hour. The filtrate was collected by filtration. The residue was then extracted again with 40 L of 60% (v / v) ethanol under the same conditions for 1.5 hours. The two filtrates were combined, and the combined filtrate was concentrated under reduced pressure at 60°C and -0.08 MPa to a viscous paste (approximately 5 L). The concentrated paste was then spray-dried (inlet air temperature 175°C, outlet air temperature 85°C) to obtain 620 g of a brownish-yellow fine powder. HPLC analysis showed that the powder contained 19.2% chlorogenic acid, 25.0% total flavonoids (calculated as rutin), 44.2% total flavonoids, and 3.3% moisture.

[0057] The preparation method of anti-aging PBAT composite material includes the following steps:

[0058] S1: Vacuum dry PBAT resin at 80℃ for 4 hours, and dry Eucommia ulmoides extract at 60℃ for 2 hours;

[0059] S2: Add the dried PBAT resin, Eucommia ulmoides extract, and PBAT-g-MAH to a high-speed mixer in proportion and mix for 5 minutes at room temperature to obtain a premix.

[0060] S3: Add the premixed material to a twin-screw extruder (screw diameter 35mm, L / D=40) for melt blending. Set the processing temperature as follows: Zone 1 160℃, Zone 2 170℃, Zone 3 175℃, Zone 4 180℃, Die head 180℃, screw speed 200rpm. The extruded strip is then cooled with water, dried, and pelletized.

[0061] Example 5

[0062] An anti-aging PBAT composite material comprises the following raw materials in parts by weight: 80 parts PBAT resin, 1 part Eucommia ulmoides extract, 0.5 parts PBAT-g-MAH (grafting rate 0.8%) and 3 parts polyethylene wax.

[0063] Eucommia ulmoides extract is prepared by the following method:

[0064] 5 kg of dried Eucommia ulmoides leaves were pulverized and passed through a 20-mesh sieve. Then, 40 L of a 50% (v / v) ethanol aqueous solution was added, and the mixture was placed in a multi-functional extraction tank and refluxed at 85℃ for 3 h. The filtrate was collected by filtration. Another 40 L of 60% (v / v) ethanol was added to the residue, and extraction was performed under the same conditions for 1.5 h. The two filtrates were combined, and the combined filtrate was concentrated under reduced pressure at 60℃ and -0.08 MPa to a viscous paste (approximately 5 L). The concentrated paste was then spray-dried (inlet air temperature 175℃, outlet air temperature 85℃) to obtain 620 g of a brownish-yellow fine powder. HPLC analysis showed that the powder contained 18.2% chlorogenic acid, 24.3% total flavonoids (calculated as rutin), 42.5% total flavonoids, and 3.3% moisture.

[0065] The preparation method of anti-aging PBAT composite material includes the following steps:

[0066] S1: Vacuum dry PBAT resin at 70℃ for 8 hours, and dry Eucommia ulmoides extract at 50℃ for 4 hours.

[0067] S2: Add the dried PBAT resin, Eucommia ulmoides extract, and PBAT-g-MAH to a high-speed mixer in proportion and mix for 15 minutes at room temperature to obtain a premix.

[0068] S3: Add the premixed material to a twin-screw extruder (screw diameter 35mm, L / D=40) for melt blending. Set the processing temperature as follows: Zone 1 150℃, Zone 2 160℃, Zone 3 170℃, Zone 4 175℃, Die head 175℃, screw speed 400rpm. The extruded strip is then cooled with water, dried, and pelletized.

[0069] Comparative Example 1

[0070] Raw material: 100 parts PBAT resin.

[0071] Without adding any additives, the sample was directly granulated using a twin-screw extruder under the same process conditions as in Example 1 to obtain sample C1 (blank control).

[0072] Comparative Example 2

[0073] Raw materials: 98 parts PBAT resin and 2 parts commercially available general-purpose composite anti-aging agent (main components are hindered phenolic antioxidant 1010 and phosphite antioxidant 168, compounded in a 1:1 ratio).

[0074] The preparation process was the same as in Example 1, yielding sample C2 (synthesis aid control).

[0075] Comparative Example 3

[0076] Raw materials: 93 parts PBAT resin and 4 parts Eucommia ulmoides extract DZ.

[0077] Without adding any compatibilizer, the preparation process was the same as in Example 1, resulting in sample C3 (control without compatibilizer).

[0078] Experimental Example

[0079] The samples obtained in Examples 1-3 and the comparative examples were dried at 80°C for 4 hours, and then blown into a film with a thickness of about 30±5μm at 160~170°C using a blown film machine for the following tests.

[0080] ① Initial mechanical property test: The tensile strength and elongation at break of the film were tested according to GB / T 1040.3-2006.

[0081] ②Accelerated UV Aging Test: Following GB / T 16422.3-2014, the film was continuously irradiated in a UV aging chamber (UVA-340 lamp, irradiance 0.68 W / m²@340 nm, black panel temperature 60℃). Tensile properties were tested at 0h, 168h, and 336h, and the elongation at break retention rate was calculated.

[0082] ③ Accelerated aging test: The film sample was suspended in a forced-air drying oven at 100±2℃. Samples were taken at 0h, 72h, and 144h, and the yellow index (YI) was determined according to ASTM E313. The increase in YI (ΔYI) was calculated.

[0083] ④ Fourier Transform Infrared Spectroscopy (FTIR) Analysis: ATR-FTIR scans were performed on the film surface before and after aging to observe the carbonyl index (1710 cm⁻¹). - The degree of molecular chain degradation was assessed by measuring the change in the ratio of the area of ​​the C=O stretching vibration peak near the internal standard peak. The test results are summarized in Table 1.

[0084] Table 1

[0085]

[0086] *Note: Sample C3 has poor compatibility and defects in the initial film, resulting in a lower initial elongation at break.

[0087] UV aging resistance: After 336 hours of UV aging, Examples E1 and E2 maintained elongation at break of 82% and 85% respectively, significantly better than the blank control C1 (28%), and slightly better than or equivalent to C2 (80%) using synthetic auxiliaries. Example E3 (low addition amount) also showed good results (75%). However, the anti-aging effect of Comparative Example C3 (without compatibilizer) was greatly reduced (55%) due to dispersion and interface problems.

[0088] Resistance to thermo-oxidative yellowing: The yellow index growth values ​​(ΔYI) of Examples E1 and E2 were 9.5 and 8.2, respectively, which were much lower than C1's 32.6 and better than C2's 10.8. C3 had a ΔYI of 20.5, further demonstrating that the compatibilizer is crucial for stabilizing the extract and exerting its antioxidant effect.

[0089] Molecular structural stability (FTIR): The carbonyl index growth rate directly reflects the degree of ester bond breakage in the molecular chain. Examples E1 and E2 showed the lowest growth rates (18%, 15%), indicating that Eucommia ulmoides extract, with the help of compatibilizer, effectively inhibited the thermal oxidative degradation of the PBAT backbone, with better results than C2 (22%), and far superior to C1 (102%) and C3 (65%).

[0090] Initial mechanical properties: The initial mechanical properties of all embodiments are comparable to those of pure PBAT (C1) and the synthetic additive sample (C2), indicating that the present invention improves anti-aging properties without negatively affecting the basic mechanical properties of the material.

[0091] In summary, this invention successfully prepared a PBAT composite material with excellent comprehensive anti-aging properties and environmental friendliness by using a specific ratio of Eucommia ulmoides extract and a reactive compatibilizer.

[0092] Although specific embodiments of the present invention have been described in detail with reference to examples, they should not be construed as limiting the scope of protection of this patent. Various modifications and variations that can be made by those skilled in the art without inventive effort within the scope described in the claims are still within the scope of protection of this patent.

Claims

1. An anti-aging PBAT composite material, characterized in that, The raw materials comprise the following parts by weight: 80-99 parts PBAT resin, 1-10 parts Eucommia ulmoides extract, 0.5-5 parts compatibilizer, and 0-5 parts additives; the compatibilizer is one or more of PBAT-g-MAH, epoxy polymers, or titanate coupling agents; the additives are one or more of lubricants, anti-hydrolysis agents, or pigments; the Eucommia ulmoides extract is prepared by the following method: hot reflux extraction of Eucommia ulmoides leaves or bark using an ethanol-water solution, followed by concentration and drying of the extract; the total content of chlorogenic acid and total flavonoids in the Eucommia ulmoides extract is >30%, and the moisture content is ≤5%.

2. The anti-aging PBAT composite material according to claim 1, characterized in that: The epoxy polymer is a glycidyl methacrylate grafted polymer.

3. The anti-aging PBAT composite material according to claim 1, characterized in that: The lubricant is stearic acid or polyethylene wax; the anti-hydrolysis agent is carbodiimide.

4. The anti-aging PBAT composite material according to claim 1, characterized in that: The volume concentration of the ethanol-water solution is 50-75%; the particle size of Eucommia ulmoides leaves or bark is 20-60 mesh; and the ratio of Eucommia ulmoides leaves or bark to the ethanol-water solution is 1g:8-15mL.

5. The anti-aging PBAT composite material according to claim 1, characterized in that: The hot reflux extraction temperature is 70~85℃, and the hot reflux extraction time is 1~3h.

6. The method for preparing the anti-aging PBAT composite material according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1: The PBAT resin is vacuum dried at 70~80℃ for 4~8h, and the Eucommia ulmoides extract is dried at 50~60℃ for 2~4h; S2: Add the dried PBAT resin, Eucommia ulmoides extract, compatibilizer and additives to a high-speed mixer in proportion, mix at room temperature for 5-15 minutes to obtain a premix; S3: The premixed material is added to a twin-screw extruder and then melt-extruded, cooled, drawn, and pelletized to obtain the final product.

7. The method for preparing the anti-aging PBAT composite material according to claim 6, characterized in that, The processing temperature settings for the twin-screw extruder are: Zone 1 150~160℃, Zone 2 160~170℃, Zone 3 170~175℃, Zone 4 175~180℃, and Die head 175~180℃; the screw speed is 200~400rpm.

8. The application of the anti-aging PBAT composite material according to any one of claims 1 to 5 in the preparation of film products.

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