A fully biodegradable resin, its preparation method and application

Abstract

The application provides a completely biodegradable resin and a preparation method and application thereof, and belongs to the technical field of biodegradable materials.The completely biodegradable resin comprises the following raw materials: carbon dioxide-based polycarbonate, a toughening agent, an anti-blocking agent and an auxiliary agent; the carbon dioxide-based polycarbonate comprises PPC-P, PPCX, PPC-Plus and other degradable polyester resin.The preparation method can significantly improve the elongation at break of the raw material, while ensuring that the material has good tensile strength.Compared with the PBAT polyester film, polyolefin film and other film materials currently circulating in the market, the degradable resin film prepared by the application has better barrier performance and antibacterial performance to carbon dioxide and other gases, and is expected to replace traditional materials and be applied in the field of plastic film.

Description

Technical Field

[0001] Currently, plastic products are widely used in many fields due to their advantages such as light weight, high strength, stable chemical properties, and low cost. However, traditional plastic products are difficult to degrade naturally in the environment, posing a significant challenge to social sustainability and environmental governance. Biodegradable resins are beginning to emerge in my country's agricultural films, packaging films, and disposable products. PLA, PBAT, and PBS are currently the most widely used biodegradable resins. However, PLA, a major biodegradable resin, is primarily made from starch- or sugar-rich grain crops such as corn and sugarcane. The sugars in these plants are converted into lactic acid through fermentation, which is then polymerized to form PLA resin. Large-scale PLA production may consume arable land resources, potentially leading to competition between people and food resources, and between food resources and land. The synthesis of PBAT and PBS relies on non-renewable petroleum resources, which is inconsistent with the concept of sustainable development.

[0002] CO2-based polycarbonates are environmentally friendly polymers synthesized primarily from carbon dioxide. They possess biodegradability and low carbon emission characteristics, making them a key alternative to traditional petroleum-based plastics. Currently, the CO2-based polycarbonate family has expanded to include several new members, such as PPC-X, PPC-P, and PPC-Plus. These materials incorporate benzene rings and cyclohexane structures into their molecular structures, increasing the rigidity of their molecular chains and raising their glass transition temperature from approximately 32°C (for the initial polymethyl ethylene carbonate, PPC) to around 50°C. Therefore, PPC-X, PPC-P, and PPC-Plus materials can meet basic usage requirements. Furthermore, these materials contain approximately 43% carbon dioxide by mass, reducing greenhouse gas emissions and dependence on petroleum resources. They also degrade naturally in the environment after use and disposal. However, the increased rigidity of the molecular structure in PPC-X, PPC-P, and PPC-Plus materials results in greater brittleness and poor impact resistance, making them difficult to process into film products.

[0003] For example, Zhang Tianwei from Professor Meng Yuezhong's research group at Sun Yat-sen University mentioned that PPC-P has an elongation of only 6%, indicating brittleness. He improved the mechanical elongation and toughness of PPC-P by blending it with commercially available biodegradable plastic PBAT, but at the same time, it significantly reduced the gas barrier properties of PPC-P (Zhang Tianwei, Liang Jiaxin, Yue Shuangshuang, et al. Acta Polymerica Sinica, 2023, 54(8):1144-1154.).

[0004] In addition, when developing high-barrier films, Deng Jiangtao also mentioned that PPC-P has an elongation of only 6%, indicating brittleness (High-Gas-Barrier and Biodegradable PPC-P / PBAT Composite Films Coated by Poly(vinyl alcohol) / borax Complexes. Surfaces 2024, 7, 517–528.). He prepared high-barrier plastic films by blending PPC-P with commercially biodegradable plastic PBAT to modify the plastic film, and then coating the surface with a blend of polyvinyl alcohol and boron compounds to improve other barrier properties.

[0005] The three PPC-P polymers with different sequence structures synthesized by Fan Congxiao were all tested and the results showed that PPC-P materials are hard and brittle materials (Fan Congxiao, Liang Jiaxin, Ye Shuxian, et al. Controllable synthesis and performance study of carbon dioxide / propylene oxide / phthalic anhydride terpolymers with different sequence structures, Acta Polymerica Sinica, 2022, 53(5):497-504.).

[0006] PPC-P has been reported more extensively in the literature, while PPC-X and PPC-Plus have been reported less frequently, as these three types of resins are currently still in the industrial-scale commercialization stage. However, both PPCX and PPC-Plus contain six-membered ring structural units of benzene or cyclohexane in their molecular structures. These factors lead to increased rigidity and decreased elongation or toughness in the final synthesized materials, making them hard and brittle materials. Toughening modification is necessary to improve their practicality and application range.

[0007] Therefore, the present invention aims to improve the elongation and toughness of materials such as PPC-X, PPC-P, and PPC-Plus through modification technology, improve their molding and processing performance, and endow them with antibacterial surface function, thereby hoping to promote their application in the field of plastic films. Summary of the Invention

[0008] In view of this, the present invention provides a fully biodegradable resin comprising the following raw materials:

[0009] Carbon dioxide-based polycarbonate, toughening agents, anti-blocking agents, and additives;

[0010] The carbon dioxide-based polycarbonate includes any one or more blends of poly(propylene carbonate-co-propylene phthalate) copolymer (PPC-P), poly(propylene carbonate-co-cyclohexane oxide-phthalate) copolymer (PPC-X), or copolymers prepared by catalytic polymerization of four or more monomers such as carbon dioxide, propylene oxide, phthalic anhydride, cyclohexane oxide, and other compounds (PPC-Plus).

[0011] Furthermore, when the carbon dioxide-based polycarbonate is PPC-X, the mass ratio of carbon dioxide-based polycarbonate, toughening agent, anti-blocking agent, and additives is 100:(20-25):(1-5):(0.1-2), and when the carbon dioxide-based polycarbonate is PPC-P, the mass ratio of carbon dioxide-based polycarbonate, toughening agent, anti-blocking agent, and additives is 100:(5-50):(1-5):(0.1-2).

[0012] Furthermore, the toughening agent includes any one or a mixture of two or more of polyethylene oxide (PEO), polypropylene oxide (PPO), polycarbonate-co-polyurethane copolymer (PPC-TPU), polymethyl ethylene carbonate (PPC), and aliphatic polycarbonate diol (PCDL).

[0013] Furthermore, the anti-blocking agent includes any one or a mixture of two or more of paraffin wax, stearic acid soap (calcium, magnesium, zinc), fatty acid amide, polydimethylsiloxane, and talc.

[0014] Furthermore, the adjuvant includes fatty acids and their salts, preferably stearic acid and its salts.

[0015] The present invention also provides a method for preparing the fully biodegradable resin, comprising mixing each raw material in proportion, drying, screw melt blending extrusion, cooling, and granulation to obtain the modified fully biodegradable resin.

[0016] Furthermore, the drying temperature is 50℃~70℃, and the drying time is 8~10h.

[0017] Furthermore, the temperature range for screw melt blending is 120℃~170℃.

[0018] An application of a fully biodegradable resin, wherein a plastic film is prepared using the fully biodegradable resin as a raw material, the thickness of the plastic film being in the range of 5 μm to 200 μm.

[0019] Furthermore, methods for preparing plastic films include, but are not limited to, blow molding, casting, calendering, and solution casting processes.

[0020] Furthermore, an antibacterial liquid is coated on both sides of the plastic film. The antibacterial liquid comprises 0.5%–5% antibacterial agent, 0.5%–2% silane coupling agent, and 93%–99% anhydrous ethanol. The thickness of the antibacterial liquid coating is 0.5 μm–20 μm.

[0021] Furthermore, the antibacterial solution is prepared by measuring according to the above proportions, stirring and dispersing at room temperature until the solution is clear and transparent.

[0022] Furthermore, the preparation method of the antibacterial agent is described in patent application number 202311154338.8, entitled "A ternary copolymer quaternary ammonium salt polymeric antibacterial agent and its preparation method and application".

[0023] Furthermore, the silane coupling agent includes any one of KH-550, KH-560, KH-570, A151, A171, etc.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The modified fully biodegradable resin of this invention not only has good tensile strength compared to unmodified PPC-P, PPC-X or PPC-Plus, but also significantly improves the elongation at break of the material, which can meet the needs of processing technology such as blown film and practical applications.

[0026] The modified fully biodegradable resin of this invention is completely biodegradable compared to traditional resins such as polyethylene, polypropylene, polyester, polyvinyl chloride, and polyethylene-vinyl acetate copolymer, and the degradation cycle can be controlled.

[0027] The plastic film prepared by this invention has higher gas barrier properties such as carbon dioxide, oxygen and water vapor compared with traditional films such as polyethylene, polypropylene, polyester, polyvinyl chloride, and polyethylene-vinyl acetate copolymer, or biodegradable plastic films such as PBAT, PLA, and PBS. It also has a long-lasting antibacterial function and is very suitable for use in plastic film applications such as food preservation film, food packaging film, and agricultural mulch film. Attached Figure Description

[0028] Figure 1 This is a comparison chart of the changes in mechanical properties of the materials in Examples 1-2 and Comparative Examples 1-4.

[0029] Figure 2 This is a comparison chart of the changes in mechanical properties of the materials in Examples 3-6 and Comparative Example 5.

[0030] Figure 3 This is a test diagram of the antibacterial properties of the material in Example 1. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0032] Unless otherwise specified, the test methods or experimental methods described in the following examples are all conventional methods; unless otherwise specified, the raw materials and additives are obtained from conventional commercial sources or prepared by conventional methods.

[0033] PPC-X (Beijing Xuyang Technology Co., Ltd., brand name: PPCX-103), PPC-P (Shandong Lianxin Environmental Protection Technology Co., Ltd., brand name: PPC-P LX101), PPC-TPU (Jiangsu Zhongke Jinlong Environmental Protection New Materials Co., Ltd., brand name: PPC-TPUT1), PEO-10W (Dow Chemical, USA, brand name: POLYOX WSR N10), Oleamide (PMC Group, USA, brand name: Armoslip CP), Polydimethylsiloxane (Hubei Chengfeng Chemical Co., Ltd., brand name: PDMS), Stearic acid (IOI Group, Malaysia, brand name: SA-1801).

[0034] Example 1

[0035] A method for preparing a fully biodegradable resin includes the following steps: Weigh the following raw materials according to the proportions: 500g of PPC-X, 100g of PPC-TPU, 5.0g of oleamide, and 2.5g of stearic acid. Then, premix the components and dry them at 50℃ for 10 hours. Finally, set the temperatures of each zone in the screw compounding equipment as follows: Zone 1 50℃ (feed inlet), Zone 2 120℃, Zone 3 160℃, Zone 4 165℃, Zone 5 170℃, and Zone 6 160℃ (die). The feed rate is 15 rpm, the screw speed is 100 rpm, and the granulator speed is 20 rpm. Under these process conditions, perform melt blending, extrusion, cooling, and granulation to obtain the modified fully biodegradable resin.

[0036] The steps of a method for preparing a film of a fully biodegradable modified resin are as follows:

[0037] The modified, fully biodegradable resin is fed into the screw hopper and melted in the temperature range of 150℃ to 160℃. After being extruded from the die, it enters a three-roll calender (front roll 150℃, speed 50 rpm, middle roll 160℃, speed 60 rpm, rear roll 150℃, speed 55 rpm). The roller pressure is set to 10MPa, the roller spacing is 30μm to 50μm, and the cooling air temperature is 30℃. After cooling and molding, it passes through a coating machine to apply an antibacterial liquid coating on both sides (controlling the coating thickness to 0.5μm to 3μm). Finally, it is dried at 35℃, wound up, and packaged.

[0038] The antibacterial solution is prepared by mixing 0.5%–5% antibacterial agent, 0.5%–2% silane coupling agent, and 93%–99% anhydrous ethanol at room temperature and stirring until uniformly dispersed to obtain the antibacterial solution.

[0039] Example 2

[0040] A method for preparing a fully biodegradable resin includes the following steps: Weigh the following raw materials according to the proportions: 500g of PPC-X, 125g of PPC-TPU, 5.0g of oleamide, and 2.5g of stearic acid. Then, premix the components and dry them at 50℃ for 10 hours. Finally, set the temperatures of each zone in the screw compounding equipment as follows: Zone 1 50℃ (feed inlet), Zone 2 120℃, Zone 3 160℃, Zone 4 165℃, Zone 5 170℃, and Zone 6 160℃ (die). The feed rate is 15 rpm, the screw speed is 100 rpm, and the granulator speed is 20 rpm. Under these process conditions, perform melt blending, extrusion, cooling, and granulation to obtain the modified fully biodegradable resin.

[0041] The steps of a method for preparing a film of a fully biodegradable modified resin are as follows:

[0042] The modified, fully biodegradable resin is fed into the screw hopper and melted in the temperature range of 150℃ to 160℃. After being extruded from the die, it enters a three-roll calender (front roll 150℃, speed 50 rpm, middle roll 160℃, speed 60 rpm, rear roll 150℃, speed 55 rpm). The roller pressure is set to 10MPa, the roller spacing is 30μm to 50μm, and the cooling air temperature is 30℃. After cooling and molding, it passes through a coating machine to apply an antibacterial liquid coating on both sides (controlling the coating thickness to 0.5μm to 3μm). Finally, it is dried at 35℃, wound up, and packaged.

[0043] The antibacterial solution is prepared by mixing 0.5%–5% antibacterial agent, 0.5%–2% silane coupling agent, and 93%–99% anhydrous ethanol at room temperature and stirring until uniformly dispersed to obtain the antibacterial solution.

[0044] Comparative Example 1

[0045] A method for preparing a fully biodegradable resin includes the following steps: Weighing the following raw materials in proportion: 500g of PPC-X, 50g of PPC-TPU, 5.0g of oleamide, and 2.5g of stearic acid. Premixing the components and drying at 50℃ for 10 hours. Then, setting the temperatures of each zone in a screw compounding equipment as follows: Zone 1 50℃ (feed inlet), Zone 2 120℃, Zone 3 160℃, Zone 4 165℃, Zone 5 170℃, and Zone 6 160℃ (die). The feed rate is 15 rpm, the screw speed is 100 rpm, and the granulator speed is 20 rpm. Under these process conditions, melt blending, extrusion, cooling, and granulation are performed to obtain the modified fully biodegradable resin.

[0046] The steps of a method for preparing a film of a fully biodegradable modified resin are as follows:

[0047] The modified, fully biodegradable resin is fed into the screw hopper and melted in the temperature range of 150℃ to 160℃. After being extruded from the die, it enters a three-roll calender (front roll 150℃, speed 50 rpm, middle roll 160℃, speed 60 rpm, rear roll 150℃, speed 55 rpm). The roller pressure is set to 10MPa, the roller spacing is 30μm to 50μm, and the cooling air temperature is 30℃. After cooling and molding, it passes through a coating machine to apply an antibacterial liquid coating on both sides (controlling the coating thickness to 0.5μm to 3μm). Finally, it is dried at 35℃, wound up, and packaged.

[0048] The antibacterial solution is prepared by mixing 0.5%–5% antibacterial agent, 0.5%–2% silane coupling agent, and 93%–99% anhydrous ethanol at room temperature and stirring until uniformly dispersed to obtain the antibacterial solution.

[0049] Comparative Example 2

[0050] A method for preparing a fully biodegradable resin includes the following steps: Weigh the following raw materials according to the proportions: 500g of PPC-X, 75g of PPC-TPU, 5.0g of oleamide, and 2.5g of stearic acid. Then, premix the components and dry them at 50℃ for 10 hours. Finally, set the temperatures of each zone in the screw compounding equipment as follows: Zone 1 50℃ (feed inlet), Zone 2 120℃, Zone 3 160℃, Zone 4 165℃, Zone 5 170℃, and Zone 6 160℃ (die). The feed rate is 15 rpm, the screw speed is 100 rpm, and the granulator speed is 20 rpm. Under these process conditions, perform melt blending, extrusion, cooling, and granulation to obtain the modified fully biodegradable resin.

[0051] The steps of a method for preparing a film of a fully biodegradable modified resin are as follows:

[0052] The modified, fully biodegradable resin is fed into the screw hopper and melted in the temperature range of 150℃ to 160℃. After being extruded from the die, it enters a three-roll calender (front roll 150℃, speed 50 rpm, middle roll 160℃, speed 60 rpm, rear roll 150℃, speed 55 rpm). The roller pressure is set to 10MPa, the roller spacing is 30μm to 50μm, and the cooling air temperature is 30℃. After cooling and molding, it passes through a coating machine to apply an antibacterial liquid coating on both sides (controlling the coating thickness to 0.5μm to 3μm). Finally, it is dried at 35℃, wound up, and packaged.

[0053] The antibacterial solution is prepared by mixing 0.5%–5% antibacterial agent, 0.5%–2% silane coupling agent, and 93%–99% anhydrous ethanol at room temperature and stirring until uniformly dispersed to obtain the antibacterial solution.

[0054] Comparative Example 3

[0055] A method for preparing a fully biodegradable resin includes the following steps: Weigh the following raw materials according to the proportions: 500g of PPC-X, 150g of PPC-TPU, 5.0g of oleamide, and 2.5g of stearic acid. Then, premix the components and dry them at 50℃ for 10 hours. Finally, set the temperatures of each zone in the screw compounding equipment as follows: Zone 1 50℃ (feed inlet), Zone 2 120℃, Zone 3 160℃, Zone 4 165℃, Zone 5 170℃, and Zone 6 160℃ (die). The feed rate is 15 rpm, the screw speed is 100 rpm, and the granulator speed is 20 rpm. Under these process conditions, perform melt blending, extrusion, cooling, and granulation to obtain the modified fully biodegradable resin.

[0056] The steps of a method for preparing a film of a fully biodegradable modified resin are as follows:

[0057] The modified, fully biodegradable resin is fed into the screw hopper and melted in the temperature range of 150℃ to 160℃. After being extruded from the die, it enters a three-roll calender (front roll 150℃, speed 50 rpm, middle roll 160℃, speed 60 rpm, rear roll 150℃, speed 55 rpm). The roller pressure is set to 10MPa, the roller spacing is 30μm to 50μm, and the cooling air temperature is 30℃. After cooling and molding, it passes through a coating machine to apply an antibacterial liquid coating on both sides (controlling the coating thickness to 0.5μm to 3μm). Finally, it is dried at 35℃, wound up, and packaged.

[0058] The antibacterial solution is prepared by mixing 0.5%–5% antibacterial agent, 0.5%–2% silane coupling agent, and 93%–99% anhydrous ethanol at room temperature and stirring until uniformly dispersed to obtain the antibacterial solution.

[0059] Comparative Example 4

[0060] The difference from Example 1 is that it does not contain toughening agents.

[0061] Example 3

[0062] A method for preparing a fully biodegradable resin includes the following steps: Weigh the following raw materials according to the proportions: 500g of PPC-P, 25g of PEO-10W (PEO with a molecular weight of 100,000), 5.0g of polydimethylsiloxane, and 2.5g of stearic acid. Then, premix the components and dry them at 50℃ for 10 hours. Finally, set the temperatures of each zone in the screw mixing equipment as follows: Zone 1 50℃ (feed inlet), Zone 2 120℃, Zone 3 140℃, Zone 4 150℃, Zone 5 150℃, and Zone 6 140℃ (die). The feed rate is 15 rpm, the screw speed is 100 rpm, and the granulator speed is 20 rpm. Under these process conditions, perform melt blending, extrusion, cooling, and granulation to obtain the modified fully biodegradable resin.

[0063] The steps of a method for preparing a film of a fully biodegradable modified resin are as follows:

[0064] The modified, fully biodegradable resin is fed into the screw hopper and melted in the temperature range of 150℃ to 160℃. After being extruded from the die, it enters a three-roll calender (front roll 150℃, speed 50 rpm, middle roll 160℃, speed 60 rpm, rear roll 150℃, speed 55 rpm). The roller pressure is set to 10MPa, the roller spacing is 30μm to 50μm, and the cooling air temperature is 30℃. After cooling and molding, it passes through a coating machine to apply an antibacterial liquid coating on both sides (controlling the coating thickness to 0.5μm to 3μm). Finally, it is dried at 35℃, wound up, and packaged.

[0065] The antibacterial solution is prepared by mixing 0.5%–5% antibacterial agent, 0.5%–2% silane coupling agent, and 93%–99% anhydrous ethanol at room temperature and stirring until uniformly dispersed to obtain the antibacterial solution.

[0066] Example 4

[0067] A method for preparing a fully biodegradable resin includes the following steps: Weigh the following raw materials according to the proportions: 500g of PPC-P, 40g of PEO-10W (PEO with a molecular weight of 100,000), 5.0g of polydimethylsiloxane, and 2.5g of stearic acid. Then, premix the components and dry them at 50℃ for 10 hours. Finally, set the temperatures of each zone in the screw mixing equipment as follows: Zone 1 50℃ (feed inlet), Zone 2 120℃, Zone 3 140℃, Zone 4 150℃, Zone 5 150℃, and Zone 6 140℃ (die). The feed rate is 15 rpm, the screw speed is 100 rpm, and the granulator speed is 20 rpm. Under these process conditions, perform melt blending, extrusion, cooling, and granulation to obtain the modified fully biodegradable resin.

[0068] The steps of a method for preparing a film of a fully biodegradable modified resin are as follows:

[0069] The modified, fully biodegradable resin is fed into the screw hopper and melted in the temperature range of 150℃ to 160℃. After being extruded from the die, it enters a three-roll calender (front roll 150℃, speed 50 rpm, middle roll 160℃, speed 60 rpm, rear roll 150℃, speed 55 rpm). The roller pressure is set to 10MPa, the roller spacing is 30μm to 50μm, and the cooling air temperature is 30℃. After cooling and molding, it passes through a coating machine to apply an antibacterial liquid coating on both sides (controlling the coating thickness to 0.5μm to 3μm). Finally, it is dried at 35℃, wound up, and packaged.

[0070] The antibacterial solution is prepared by mixing 0.5%–5% antibacterial agent, 0.5%–2% silane coupling agent, and 93%–99% anhydrous ethanol at room temperature and stirring until uniformly dispersed to obtain the antibacterial solution.

[0071] Example 5

[0072] A method for preparing a fully biodegradable resin includes the following steps: Weigh the following raw materials according to the proportions: 500g of PPC-P, 60g of PEO-10W (PEO with a molecular weight of 100,000), 5.0g of polydimethylsiloxane, and 2.5g of stearic acid. Then, premix the components and dry them at 50℃ for 10 hours. Finally, set the temperatures of each zone in the screw mixing equipment as follows: Zone 1 50℃ (feed inlet), Zone 2 120℃, Zone 3 140℃, Zone 4 150℃, Zone 5 150℃, and Zone 6 140℃ (die). The feed rate is 15 rpm, the screw speed is 100 rpm, and the granulator speed is 20 rpm. Under these process conditions, perform melt blending, extrusion, cooling, and granulation to obtain the modified fully biodegradable resin.

[0073] The steps of a method for preparing a film of a fully biodegradable modified resin are as follows:

[0074] The modified, fully biodegradable resin is fed into the screw hopper and melted in the temperature range of 150℃ to 160℃. After being extruded from the die, it enters a three-roll calender (front roll 150℃, speed 50 rpm, middle roll 160℃, speed 60 rpm, rear roll 150℃, speed 55 rpm). The roller pressure is set to 10MPa, the roller spacing is 30μm to 50μm, and the cooling air temperature is 30℃. After cooling and molding, it passes through a coating machine to apply an antibacterial liquid coating on both sides (controlling the coating thickness to 0.5μm to 3μm). Finally, it is dried at 35℃, wound up, and packaged.

[0075] The antibacterial solution is prepared by mixing 0.5%–5% antibacterial agent, 0.5%–2% silane coupling agent, and 93%–99% anhydrous ethanol at room temperature and stirring until uniformly dispersed to obtain the antibacterial solution.

[0076] Example 6

[0077] A method for preparing a fully biodegradable resin includes the following steps: Weigh the following raw materials according to the proportions: 500g of PPC-P, 75g of PEO-10W (PEO with a molecular weight of 100,000), 5.0g of polydimethylsiloxane, and 2.5g of stearic acid. Then, premix the components and dry them at 50℃ for 10 hours. Finally, set the temperatures of each zone in the screw mixing equipment as follows: Zone 1 50℃ (feed inlet), Zone 2 120℃, Zone 3 140℃, Zone 4 150℃, Zone 5 150℃, and Zone 6 140℃ (die). The feed rate is 15 rpm, the screw speed is 100 rpm, and the granulator speed is 20 rpm. Under these process conditions, perform melt blending, extrusion, cooling, and granulation to obtain the modified fully biodegradable resin.

[0078] The steps of a method for preparing a film of a fully biodegradable modified resin are as follows:

[0079] The modified, fully biodegradable resin is fed into the screw hopper and melted in the temperature range of 150℃ to 160℃. After being extruded from the die, it enters a three-roll calender (front roll 150℃, speed 50 rpm, middle roll 160℃, speed 60 rpm, rear roll 150℃, speed 55 rpm). The roller pressure is set to 10MPa, the roller spacing is 30μm to 50μm, and the cooling air temperature is 30℃. After cooling and molding, it passes through a coating machine to apply an antibacterial liquid coating on both sides (controlling the coating thickness to 0.5μm to 3μm). Finally, it is dried at 35℃, wound up, and packaged.

[0080] The antibacterial solution is prepared by mixing 0.5%–5% antibacterial agent, 0.5%–2% silane coupling agent, and 93%–99% anhydrous ethanol at room temperature and stirring until uniformly dispersed to obtain the antibacterial solution.

[0081] Comparative Example 5

[0082] The difference from Example 3 is that PEO-10W toughening agent was not added.

[0083] Example 7

[0084] A method for preparing a fully biodegradable resin includes the following steps: Weigh the following raw materials according to the proportions: 500g of PPC-X, 40g of PEO-10W, 5.0g of oleic amide, and 2.5g of stearic acid. Then, premix the components and dry them at 50℃ for 10 hours. Finally, set the temperatures of each zone in the screw compounding equipment as follows: Zone 1 50℃ (feed inlet), Zone 2 120℃, Zone 3 160℃, Zone 4 165℃, Zone 5 170℃, and Zone 6 160℃ (die). The feed rate is 15 rpm, the screw speed is 100 rpm, and the granulator speed is 20 rpm. Under these process conditions, perform melt blending, extrusion, cooling, and granulation to obtain the modified fully biodegradable resin.

[0085] The steps of a method for preparing a film of a fully biodegradable modified resin are as follows:

[0086] The modified, fully biodegradable resin is fed into the screw hopper and melted in the temperature range of 150℃ to 160℃. After being extruded from the die, it enters a three-roll calender (front roll 150℃, speed 50 rpm, middle roll 160℃, speed 60 rpm, rear roll 150℃, speed 55 rpm). The roller pressure is set to 10MPa, the roller spacing is 30μm to 50μm, and the cooling air temperature is 30℃. After cooling and molding, it passes through a coating machine to apply an antibacterial liquid coating on both sides (controlling the coating thickness to 0.5μm to 3μm). Finally, it is dried at 35℃, wound up, and packaged.

[0087] The antibacterial solution is prepared by mixing 0.5%–5% antibacterial agent, 0.5%–2% silane coupling agent, and 93%–99% anhydrous ethanol at room temperature and stirring until uniformly dispersed to obtain the antibacterial solution.

[0088] Example 8

[0089] A method for preparing a fully biodegradable resin includes the following steps: Weigh the following raw materials according to the proportions: 500g of PPC-P, 100g of PPC-TPU, 5.0g of polydimethylsiloxane, and 2.5g of stearic acid. Then, premix the components and dry them at 50℃ for 10 hours. Finally, set the temperatures of each zone in the screw compounding equipment as follows: Zone 1 50℃ (feed inlet), Zone 2 120℃, Zone 3 140℃, Zone 4 150℃, Zone 5 160℃, and Zone 6 150℃ (die). The feed rate is 15 rpm, the screw speed is 100 rpm, and the granulator speed is 20 rpm. Under these process conditions, perform melt blending, extrusion, cooling, and granulation to obtain the modified fully biodegradable resin.

[0090] The steps of a method for preparing a film of a fully biodegradable modified resin are as follows:

[0091] The modified, fully biodegradable resin is fed into the screw hopper and melted in the temperature range of 150℃ to 160℃. After being extruded from the die, it enters a three-roll calender (front roll 150℃, speed 50 rpm, middle roll 160℃, speed 60 rpm, rear roll 150℃, speed 55 rpm). The roller pressure is set to 10MPa, the roller spacing is 30μm to 50μm, and the cooling air temperature is 30℃. After cooling and molding, it passes through a coating machine to apply an antibacterial liquid coating on both sides (controlling the coating thickness to 0.5μm to 3μm). Finally, it is dried at 35℃, wound up, and packaged.

[0092] The antibacterial solution is prepared by mixing 0.5%–5% antibacterial agent, 0.5%–2% silane coupling agent, and 93%–99% anhydrous ethanol at room temperature and stirring until uniformly dispersed to obtain the antibacterial solution.

[0093] Performance testing:

[0094] (i) Mechanical property tests were conducted on Examples 1-8 and Comparative Examples 1-5. The test methods were as follows:

[0095] Refer to GB / T 1040.3-2006 Determination of tensile properties of plastics Part 3: Test conditions for films and sheets.

[0096] Test Procedure: First, under conditions of 150℃ and 10MPa, the modified fully biodegradable resin was pressed into a thin film sample with a thickness of approximately 200μm in a flat vulcanizing machine. Then, it was cut into dumbbell-shaped tensile test strips using a standard cutting die. Next, the strips were conditioned under standard conditions for 24 hours (relative humidity 50%, 25℃). Then, the tensile speed of the universal testing machine was set to 50mm / min, and parameters such as the average thickness of the strips and the width of the strips between gauge lengths were input. Subsequently, tensile tests were performed on the strips, with each strip tested in parallel 5 times. Finally, the average mechanical property test value of each strip was calculated.

[0097] Refer to GB / T 1043.1-2008 Determination of impact properties of simply supported plastic beams Part 1: Non-instrumental impact testing

[0098] Test Procedure: First, an 80mm×10mm×4mm unnotched test specimen is molded using an injection molding machine and conditioned for 24 hours under standard conditions. The simply supported beam impact testing machine is then turned on, and after 10 minutes of equilibration, test parameters (pendulum weight, specimen information, etc.) are input to begin testing the blank value (the impact energy of the pendulum consumed by air friction resistance). The pendulum is then raised to the specified height, and the specimen is placed on the testing machine support with the pendulum's impact edge aligned with the center of the specimen's dimensions. Finally, the pendulum is released, and the impact energy value displayed on the instrument is recorded to complete the impact test. Each specimen is measured in parallel five times, and the average impact absorption energy of each specimen is calculated.

[0099] The mechanical property test results of Examples 1-8 and Comparative Examples 1-5 are shown in Table 1:

[0100] Table 1

[0101]

[0102] As shown in Table 1, the fully biodegradable resin provided by this invention exhibits significantly improved elongation at break and impact strength. The unmodified PPC-X has an elongation at break of only 3.49% and an impact strength of 5.7 kJ / m². 2 The modified PPC-X obtained by the method provided in this invention exhibits an elongation at break of 99.22% and an impact strength of 36.7 kJ / m. 2 .

[0103] Furthermore, as can be seen from Examples 1-2 and Comparative Examples 1-3, when the amount of toughening agent added is small, although the tensile strength of PPC-X is improved, the elongation at break is poor, indicating that PPC-X is still quite brittle. When the amount of toughening agent added is large, although the elongation at break of PPC-X is significantly improved, the tensile strength is significantly reduced, which cannot meet the requirements of practical applications in film processing. That is, only a specific proportion of toughening agent can effectively improve the elongation at break of PPC-X and ensure good tensile strength.

[0104] As can be seen from Examples 3-6 and Comparative Example 5, compared with unmodified PPC-P, the elongation at break and impact strength of PPC-P modified with toughening agent are increased several times. Before modification, the elongation of PPC-P was only 3.77%, and the impact strength was only 10.2 kJ / m. 2 After modification, the elongation of PPC-P increased to 712.59%, and the impact strength reached 74.6 kJ / m. 2This ensures that the overall mechanical properties of PPC-P meet the requirements of blown film processing and practical applications.

[0105] As shown in Table 1, PPC-X and PPC-P have high strength before modification, but low elongation and impact strength, and are quite brittle, making them prone to breakage during film fabrication. However, after modification with toughening agents, the elongation at break and toughness of the materials are significantly improved, while the tensile strength of the materials still meets the requirements of blown film processing and practical applications.

[0106] Furthermore, since the added toughening agents are all fully biodegradable materials, the biodegradability of the modified raw materials will not be affected.

[0107] (ii) Barrier performance tests were conducted on Examples 1-8 and Comparative Examples 1-5. The test method was in accordance with GB / T1038.1-2022 Test method for gas permeability of plastic products, films and sheets, Part 1: Differential pressure method.

[0108] Test Procedure: First, under conditions of 150℃ and 10MPa, the modified fully biodegradable resin was pressed into a thin film sample with a thickness of approximately 200μm in a flat vulcanizing machine. Then, it was conditioned under standard conditions for 24 hours (50% relative humidity, 25℃). Next, it was cut into 3.5cm × 3.5cm test samples using a standard cutting die. The gas permeability meter was turned on, and the flow rates of the corresponding test gas and nitrogen were adjusted. Preheating was allowed for 20 minutes. The 3.5cm × 3.5cm test samples were then sealed in the center of a 3cm × 3cm cavity in aluminum foil, leaving only 9cm exposed. 2 A sample of the area is used for testing. Then, sealant is applied to both sealed surfaces of the test chamber. Next, aluminum foil with the film sample attached is placed in the center of the test chamber. Finally, the upper and lower parts of the test chamber are joined and sealed, and then installed in the test chamber position of the gas permeability meter. Test parameters are set: temperature, humidity, gas flow rate, film thickness, film area, etc., and then the test is started.

[0109] The barrier performance test results of Examples 1-8, Comparative Examples 1-5, PBAT film, PBS film, PLA film, LDPE film, and PET film are shown in Table 2:

[0110] Table 2

[0111]

[0112]

[0113] As shown in Table 2, the barrier properties of PPC-TPU-toughened modified PPCX to gases such as carbon dioxide, oxygen and water vapor are slightly improved compared to pure PPCX. This may be due to the good compatibility between the two and the physical cross-linking between them.

[0114] The PPC-P modified with PEO-10W exhibits improved barrier properties against gases such as carbon dioxide, oxygen, and water vapor compared to pure PPC-P. This may be because the toughening agent PEO forms microcrystals in the PPC-P, thereby enhancing the material's gas barrier properties.

[0115] Compared to existing commercially available PBAT films, PBS films, and traditional LDPE and PET films, the PPCX and PPC-P modified composite films have significant comprehensive performance advantages and are expected to replace traditional plastic films.

[0116] (iii) Antibacterial performance tests were conducted on Examples 1-8 and Comparative Examples 1-5. The test methods referred to GB / T31402-2023 "Determination of antibacterial activity of plastics and other non-porous materials". Staphylococcus aureus, Escherichia coli, and Candida albicans were used as test bacteria. Bacterial culture dishes were cultured on nutrient agar, and four loops of sterile inoculation were used for Z-shaped inoculation. The results were observed after incubation at 37°C for 48 hours. The antibacterial effect of the sample in Example 1 is shown in the attached figure. Figure 3 As shown in the figure. Experimental tests show that the experimental sample surface has good antibacterial effects against Staphylococcus aureus, Escherichia coli, and Candida albicans. No bacterial growth was observed on the film surface, indicating that the plastic film prepared by the present invention has a broad-spectrum antibacterial effect.

[0117] In addition, the present invention also conducted antibacterial performance tests on the samples prepared in Examples 2-8 respectively. The antibacterial effect was comparable to that in Example 1, and it had a good antibacterial effect against Staphylococcus aureus, Escherichia coli and Candida albicans. No bacterial growth was observed on the surface of the film.

[0118] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A fully biodegradable resin, characterized in that, Including the following raw materials: Carbon dioxide-based polycarbonate, toughening agents, anti-blocking agents, and additives; When the carbon dioxide-based polycarbonate is PPC-X, the mass ratio of carbon dioxide-based polycarbonate, toughening agent, anti-blocking agent and additives is 100:(20-25):(1-5):(0.1-2); When the carbon dioxide-based polycarbonate is PPC-P, the mass ratio of carbon dioxide-based polycarbonate, toughening agent, anti-blocking agent, and additives is 100:(5-50):(1-5):(0.1-2); The toughening agent includes any one of polyethylene oxide, polypropylene oxide, and polycarbonate-co-polyurethane copolymer.

2. The fully biodegradable resin according to claim 1, characterized in that, The anti-blocking agent includes any one or a mixture of two or more of paraffin wax, stearic acid soap, fatty acid amide, polydimethylsiloxane, and talc.

3. The fully biodegradable resin according to claim 1, characterized in that, The additives include fatty acids and their salts.

4. The method for preparing the fully biodegradable resin according to any one of claims 1-3, characterized in that, The process includes mixing the raw materials in proportion, drying, screw melt blending and extrusion, cooling, and granulation to obtain a modified, fully biodegradable resin.

5. The method for preparing the fully biodegradable resin according to claim 4, characterized in that, The drying temperature is 50℃~70℃, and the drying time is 8~10h.

6. The method for preparing the fully biodegradable resin according to claim 5, characterized in that, The temperature range for screw melt blending is 120℃~170℃.

7. The application of the fully biodegradable resin according to any one of claims 1-3, or the fully biodegradable resin prepared by the method according to claims 4-6, characterized in that, A plastic film is prepared using a fully biodegradable resin as a raw material, wherein the thickness of the plastic film is 5 μm to 200 μm.

8. The application of the fully biodegradable resin according to claim 7, characterized in that, An antibacterial liquid is coated on both sides of a plastic film. The composition of the antibacterial liquid includes 0.5% to 5% antibacterial agent, 0.5% to 2% silane coupling agent, and 93% to 99% anhydrous ethanol.

9. The application of the fully biodegradable resin according to claim 8, characterized in that, The silane coupling agent includes any one of KH-550, KH-560, KH-570, A151, and A171.

Images