Plastic material for disposable tableware and preparation method thereof

Abstract

The invention discloses a microwave oven-resistant degradable disposable tableware plastic material and a preparation method thereof. The material is prepared from the following raw materials in parts by weight: 70-85 parts of polylactic acid, 10-20 parts of heat-resistant modified resin, 3-8 parts of a nucleating agent, 3-5 parts of a compatilizer, 5-10 parts of a bio-based toughening agent and 0.5-1.5 parts of a lubricant. According to the formula, the heat-resistant efficiency factor phi is larger than or equal to 45, the interface stability coefficient psi is 5%-25%, and high heat resistance and component compatibility of the material are guaranteed. The preparation method comprises the steps of raw material drying and mixing, melt blending granulation and heat treatment after molding. The thermal deformation temperature of the obtained product is not lower than 120 DEG C, and the product can tolerate a microwave oven heating environment, has complete biodegradability, good mechanical properties and use safety, and can be widely applied to production of disposable tableware such as meal boxes, soup bowls, cups, trays and the like.

Description

Technical Field

[0001] This application relates to the field of disposable tableware technology, specifically to a plastic material for disposable tableware and its preparation method. Background Technology

[0002] With the accelerating pace of modern life and the booming global food delivery industry, disposable tableware has become deeply integrated into daily life and an indispensable part of modern service industries due to its unparalleled convenience and hygiene. However, the "white pollution" problem caused by traditional petroleum-based plastic tableware (such as polypropylene PP) is becoming increasingly serious, prompting a growing call worldwide for environmentally friendly alternative materials. Bio-based biodegradable materials, represented by polylactic acid (PLA), are considered one of the ideal solutions. They are derived from renewable resources and can eventually degrade into carbon dioxide and water under certain conditions, perfectly aligning with the concept of sustainable development.

[0003] Currently, mainstream environmentally friendly alternatives on the market mainly focus on bio-based or biodegradable material systems. For example, Chinese patent CN119613933A discloses a method for improving the overall performance of PLA / PBS blends using compatibilizers, by introducing PBS to improve the brittleness of PLA; another patent CN102212212B describes a method for preparing solvent-based lignin-modified starch thermoplastic composite materials. These technical solutions aim to reduce dependence on fossil resources and possess biodegradable properties to varying degrees, providing a feasible path to alleviate environmental pressure.

[0004] However, these existing biodegradable materials have revealed a key technical flaw when moving towards large-scale market application, especially in the hope of completely replacing traditional plastic tableware: they generally cannot withstand high temperatures, particularly in microwave ovens. Specifically, pure PLA or simply blended modified PLA materials typically have a heat distortion temperature of only around 55°C, making them prone to softening and deformation when filled with hot soup or food or microwaved, severely impacting user experience and safety. While traditional PP tableware can withstand microwave heating, its non-biodegradable nature runs counter to environmental trends. Therefore, there has long been an urgent technical need in the industry: to develop a high-performance disposable tableware material that can meet demanding high-temperature usage conditions while also achieving complete biodegradability. Summary of the Invention

[0005] This application provides a cost-effective material solution that combines excellent heat resistance, complete biodegradability, and good mechanical properties, which can effectively solve the problems in the background art.

[0006] To achieve the above objectives, this application provides the following technical solution: a microwave-safe, biodegradable disposable tableware plastic material, characterized in that it is made from raw materials comprising the following parts by weight:

[0007] Polylactic acid: 70-85 parts;

[0008] Heat-resistant modified resin: 10-20 parts;

[0009] Nucleating agent: 3-8 parts;

[0010] Compatibilizer: 3-5 parts;

[0011] Bio-based toughening agent: 5-10 parts;

[0012] Lubricant: 0.5-1.5 parts;

[0013] The material, after being prepared and shaped, has a heat distortion temperature of not less than 120°C, making it suitable for microwave oven heating environments.

[0014] According to claim 1, the plastic material is characterized in that the heat-resistant modified resin is one of polypropylene carbonate or polybutylene adipate / terephthalate.

[0015] The plastic material according to claim 1 or 2 is characterized in that its formulation components satisfy a heat resistance performance factor Φ ≥ 45, wherein the formula for calculating the heat resistance performance factor Φ is:

[0016] Φ==(W n / W pla )×(S n ×1000)

[0017] Among them, W n The nucleating agent is expressed in parts by weight.

[0018] W pla The weight parts of the polylactic acid;

[0019] S n The specific surface area of ​​the nucleating agent is expressed in m². 2 / g.

[0020] According to claim 3, the plastic material is characterized in that its formulation components further satisfy the requirement that the interfacial stability coefficient Ψ is in the range of 5% to 25%, wherein the formula for calculating the interfacial stability coefficient Ψ is:

[0021] Ψ=(W c / (W rm +W f ))×100%

[0022] Among them, W c The amount is the weight part of the compatibilizer;

[0023] W rm This refers to the parts by weight of the heat-resistant modified resin;

[0024] W f This refers to the weight parts of the bio-based toughening agent.

[0025] According to claim 3, the plastic material is characterized in that the nucleating agent is talc powder or mica powder with a lamellar structure, its particle size D50 is less than 5 μm, and its specific surface area S n Not less than 15m 2 / g.

[0026] A method for preparing a microwave-safe, biodegradable disposable tableware plastic material as described in any one of claims 1-5, characterized by comprising the following steps:

[0027] a. Drying and mixing: Dry polylactic acid and heat-resistant modified resin at 80-100℃ until the moisture content is less than 0.025%; mix the dried components with nucleating agent, compatibilizer, bio-based toughening agent and lubricant in a high-speed mixer according to the formula to obtain a premix;

[0028] b. Melt blending and granulation: The premixed material is fed into a twin-screw extruder and melt-blended, extruded, cooled, and granulated within a temperature range of 165-185℃ to obtain masterbatch;

[0029] c. Molding and heat treatment: The masterbatch is molded into a tableware blank by injection molding or compression molding, and then the tableware blank is heat-treated at 100-110℃ for 15-30 minutes to obtain the disposable tableware.

[0030] According to the preparation method of claim 6, the screw speed of the twin-screw extruder in step b is 250-350 rpm.

[0031] According to the preparation method of claim 6, the heat treatment in step c is carried out in a hot air circulating oven or an infrared radiation heating box.

[0032] A disposable tableware, characterized in that it is made of the plastic material according to any one of claims 1-5, and its heat distortion temperature is not less than 120°C, and it can withstand microwave heating.

[0033] According to claim 9, the disposable tableware is characterized in that the tableware is a lunch box, soup bowl, cup or tray.

[0034] Compared with the prior art, the beneficial effects of this application are:

[0035] 1. Through the synergistic effect of specific components and careful microstructure design, this invention significantly improves the heat distortion temperature of the material, enabling its products to stably withstand the high-temperature environment of microwave oven heating, overcoming the fatal defect of traditional biodegradable tableware softening when heated, and broadening the application scenarios of environmentally friendly tableware.

[0036] 2. By introducing a highly efficient compatibilizer and precisely controlling its dosage, this invention ensures a strong bond between multiphase components such as polylactic acid matrix, heat-resistant modified resin, and bio-based toughening agent. This results in excellent toughness, rigidity, and durability of the product while maintaining its complete biodegradability, and guarantees dimensional stability and safety under microwave heating conditions.

[0037] 3. The main raw materials used in this invention are derived from renewable resources, and the product can be completely biodegraded under specific conditions, fundamentally reducing environmental pressure. At the same time, its manufacturing process is mature and cost-controllable, successfully breaking down the technical barrier that "environmental protection" and "high performance" are mutually exclusive, providing a product with strong market competitiveness for large-scale replacement of traditional plastic tableware. Attached Figure Description

[0038] Figure 1 This is a flowchart of the method in this application. Detailed Implementation

[0039] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0040] Please see Figure 1 This application provides the following technical solution: a microwave-safe, biodegradable disposable tableware plastic material, made from the following raw materials in parts by weight:

[0041] Polylactic acid: 70 parts;

[0042] Heat-resistant modified resin: polypropylene carbonate (PPC), 15 parts;

[0043] Nucleating agent: Talc (lamellar structure, particle size D50 of 4μm, specific surface area S) n 18m 2 / g), 5 portions;

[0044] Compatibilizer: Maleic anhydride grafted polylactic acid (PLA-g-MAH), 4 parts;

[0045] Bio-based toughening agent: Polycaprolactone (PCL), 8 parts;

[0046] Lubricant: Zinc stearate, 1 part.

[0047] After being prepared and molded, the material has a heat distortion temperature of not less than 120℃, making it suitable for microwave oven heating environments. Its formulation components satisfy a heat resistance performance factor Φ≥45, calculated as Φ=(5 / 70)×(18×1000)≈51.4; simultaneously, it satisfies an interface stability coefficient Ψ ranging from 5% to 25%, calculated as Ψ=(4 / (15+8))×100%≈17.4%.

[0048] The preparation method includes the following steps:

[0049] a. Drying and mixing: Dry polylactic acid and polypropylene carbonate at 90°C for 4 hours until the moisture content is less than 0.025%; according to the formula, place the dried components, nucleating agent, compatibilizer, bio-based toughening agent and lubricant into a high-speed mixer and mix for 10 minutes until uniformly mixed to obtain a premix.

[0050] b. Melt blending and granulation: The premixed material is fed into a twin-screw extruder and melt blended in a temperature range of 170-180℃. The screw speed is set to 300 rpm. The material is then extruded, cooled, and pelletized to obtain masterbatch.

[0051] c. Molding and heat treatment: The masterbatch is molded into a lunch box blank through injection molding, and then the tableware blank is placed in a hot air circulating oven at 105°C for heat treatment for 20 minutes to obtain the disposable tableware.

[0052] How it works during use:

[0053] This embodiment uses polylactic acid (PLA) as the matrix material, providing biodegradability and basic mechanical properties; polypropylene carbonate (PPC) is used as a heat-resistant modified resin to effectively improve the material's thermal stability; talc nucleating agent promotes PLA crystallization, thereby increasing the heat distortion temperature; compatibilizer ensures interfacial bonding between multiphase components, preventing phase separation; bio-based toughening agent enhances the material's toughness and prevents brittleness; lubricant improves processing fluidity. The heat treatment step further optimizes the crystal structure, enabling the product to maintain shape stability during microwave heating, achieving a heat distortion temperature of 125°C, and meeting the degradation performance standard of EN13432.

[0054] Advantages: The product of this embodiment has high heat resistance, good toughness and complete biodegradability, and low cost, making it suitable for large-scale production of disposable tableware such as lunch boxes.

[0055] Example 2

[0056] A microwave-safe, biodegradable disposable tableware plastic material, made from the following raw materials in parts by weight:

[0057] Polylactic acid: 80 parts;

[0058] Heat-resistant modified resin: Polybutylene adipate / terephthalate (PBAT), 12 parts;

[0059] Nucleating agent: Mica powder (lamellar structure, particle size D50 of 3μm, specific surface area S) n 20m 2 / g), 4 portions;

[0060] Compatibilizer: Epoxy-based compatibilizer, 3.5 parts;

[0061] Bio-based toughening agent: Polyhydroxyalkanoate (PHA), 6 parts;

[0062] Lubricant: Polyethylene wax, 0.8 parts.

[0063] After being prepared and molded, the material produces an article with a heat distortion temperature of not less than 120℃, making it suitable for microwave oven heating environments. Its formulation components satisfy a heat resistance performance factor Φ≥45, calculated as Φ=(4 / 80)×(20×1000)=50; simultaneously, it satisfies an interface stability coefficient Ψ ranging from 5% to 25%, calculated as Ψ=(3.5 / (12+6))×100%≈19.4%.

[0064] The preparation method includes the following steps:

[0065] a. Drying and mixing: Dry polylactic acid and PBAT at 85°C for 5 hours until the moisture content is less than 0.025%; mix the dried components with nucleating agent, compatibilizer, bio-based toughening agent and lubricant in a high-speed mixer for 8 minutes according to the formula, and mix evenly to obtain a premix.

[0066] b. Melt blending and granulation: The premixed material is fed into a twin-screw extruder and melt blended in a temperature range of 165-175℃. The screw speed is set to 280 rpm. The material is then extruded, cooled, and pelletized to obtain masterbatch.

[0067] c. Molding and heat treatment: The masterbatch is molded into a soup bowl blank through injection molding, and then the tableware blank is placed in an infrared radiation heating box at 100°C for heat treatment for 25 minutes to obtain the disposable tableware.

[0068] How it works during use:

[0069] This embodiment utilizes PBAT as a heat-resistant modified resin, which complements polylactic acid to improve the material's thermal properties and flexibility. Mica powder, a nucleating agent, has a high specific surface area, effectively increasing nucleation sites and enhancing crystallinity. Epoxy-based compatibilizers strengthen interfacial adhesion and prevent component separation. PHA toughening agent improves impact strength. Lubricants reduce processing energy consumption. Heat treatment is performed in an infrared radiation heating chamber, ensuring uniform heat conduction and achieving a heat distortion temperature of 122°C for the product. No deformation or leakage occurs after microwave heating.

[0070] Advantages: The product of this embodiment has excellent heat resistance and high interface stability, making it suitable for scenarios such as soup bowls that need to hold hot liquids, while maintaining complete biodegradability.

[0071] Example 3

[0072] A microwave-safe, biodegradable disposable tableware plastic material, made from the following raw materials in parts by weight:

[0073] Polylactic acid: 75 parts;

[0074] Heat-resistant modified resin: polypropylene carbonate (PPC), 18 parts;

[0075] Nucleating agent: Talc (lamellar structure, particle size D50 of 4.5 μm, specific surface area S) n 16m 2 / g), 6 portions;

[0076] Compatibilizer: Maleic anhydride grafted polylactic acid (PLA-g-MAH), 4.5 parts;

[0077] Bio-based toughening agent: Polycaprolactone (PCL), 7 parts;

[0078] Lubricant: Calcium stearate, 1.2 parts.

[0079] After being prepared and molded, the material produces an article with a heat distortion temperature of not less than 120℃, making it suitable for microwave oven heating environments. Its formulation components satisfy a heat resistance performance factor Φ≥45, calculated as Φ=(6 / 75)×(16×1000)=51.2; simultaneously, it satisfies an interface stability coefficient Ψ ranging from 5% to 25%, calculated as Ψ=(4.5 / (18+7))×100%=18%.

[0080] The preparation method includes the following steps:

[0081] a. Drying and mixing: Dry polylactic acid and polypropylene carbonate at 95°C for 4 hours until the moisture content is less than 0.025%; according to the formula, place the dried components, nucleating agent, compatibilizer, bio-based toughening agent and lubricant into a high-speed mixer and mix for 12 minutes until uniformly mixed to obtain a premix.

[0082] b. Melt blending and granulation: The premixed material is fed into a twin-screw extruder and melt-blended in a temperature range of 175-185℃. The screw speed is set to 320 rpm. The material is then extruded, cooled, and pelletized to obtain masterbatch.

[0083] c. Molding and heat treatment: The masterbatch is molded into a tray blank through a compression molding process, and then the tableware blank is placed in a hot air circulating oven at 110°C for heat treatment for 15 minutes to obtain the disposable tableware.

[0084] How it works during use:

[0085] This embodiment optimizes the formulation and process parameters. The high specific surface area and layered structure of the nucleating agent talc effectively promote polylactic acid crystallization. The heat-resistant modified resin PPC enhances thermal stability, the compatibilizer ensures uniform multiphase dispersion, and the toughening agent strengthens impact resistance. After heat treatment, the material exhibits a perfect crystal structure and a heat distortion temperature of 128°C, making it suitable for high-intensity microwave heating environments. Furthermore, the material has been tested and found to have excellent safety, with no release of harmful substances.

[0086] Material safety testing:

[0087] The trays prepared in this embodiment were subjected to high-temperature environmental harmful gas release testing according to GB9685-2016 National Food Safety Standard and ISO16000-6 Indoor Air Testing Standard. The samples were placed in a 120℃ oven and heated for 30 minutes. The released gases were collected and analyzed using gas chromatography-mass spectrometry (GC-MS, Agilent 7890B / 5977A). The results showed that no formaldehyde, benzene, volatile organic compounds (VOCs), or other harmful gases were detected, and the total volatile organic compound (TVOC) release was less than 0.1 mg / m³. 3 It meets food safety and environmental protection requirements.

[0088] The product of this embodiment has extremely high heat resistance and safety, making it suitable for scenarios such as trays that need to withstand long-term microwave heating. It is also completely biodegradable, making it environmentally friendly and safe.

[0089] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A microwave-safe, biodegradable disposable tableware plastic material, characterized in that, Made from the following raw materials in parts by weight: Polylactic acid: 70-85 parts; Heat-resistant modified resin: 10-20 parts; Nucleating agent: 3-8 parts; Compatibilizer: 3-5 parts; Bio-based toughening agent: 5-10 parts; Lubricant: 0.5-1.5 parts; The material, after being prepared and shaped, has a heat distortion temperature of not less than 120°C, making it suitable for microwave oven heating environments.

2. The plastic material according to claim 1, characterized in that, The heat-resistant modified resin is one of polypropylene carbonate or polybutylene adipate / terephthalate.

3. The plastic material according to claim 1 or 2, characterized in that, Its formulation components satisfy a heat resistance performance factor Φ≥45, and the formula for calculating the heat resistance performance factor Φ is as follows: Φ==(W n / W pla )×(S n ×1000) Among them, W n The nucleating agent is expressed in parts by weight. W pla The weight parts of the polylactic acid; S n The specific surface area of ​​the nucleating agent is expressed in m². 2 / g.

4. The plastic material according to claim 3, characterized in that, Its formulation components also satisfy the requirement that the interfacial stability coefficient Ψ is in the range of 5% to 25%, and the formula for calculating the interfacial stability coefficient Ψ is as follows: Ψ=(W c / (W rm +W f ))×100% Among them, W c The amount is the weight of the compatibilizer; W rm This refers to the parts by weight of the heat-resistant modified resin. W f This refers to the weight parts of the bio-based toughening agent.

5. The plastic material according to claim 3, characterized in that, The nucleating agent is talc or mica powder with a lamellar structure, a particle size D50 of less than 5 μm, and a specific surface area S. n Not less than 15m 2 / g.

6. A method for preparing a microwave-safe biodegradable disposable tableware plastic material as described in any one of claims 1-5, characterized in that, Includes the following steps: a. Drying and mixing: Dry polylactic acid and heat-resistant modified resin at 80-100℃ until the moisture content is less than 0.025%; mix the dried components with nucleating agent, compatibilizer, bio-based toughening agent and lubricant in a high-speed mixer according to the formula to obtain a premix; b. Melt blending and granulation: The premixed material is fed into a twin-screw extruder and melt-blended, extruded, cooled, and granulated within a temperature range of 165-185℃ to obtain masterbatch; c. Molding and heat treatment: The masterbatch is molded into a tableware blank by injection molding or compression molding, and then the tableware blank is heat-treated at 100-110℃ for 15-30 minutes to obtain the disposable tableware.

7. The preparation method according to claim 6, characterized in that, The screw speed of the twin-screw extruder described in step b is 250-350 rpm.

8. The preparation method according to claim 6, characterized in that, The heat treatment described in step c is carried out in a hot air circulating oven or an infrared radiation heating chamber.

9. A disposable tableware, characterized in that, Made of any one of the plastic materials claimed in claims 1-5, and having a heat distortion temperature of not less than 120°C, and capable of withstanding microwave oven heating.

10. The disposable tableware according to claim 9, characterized in that, The tableware refers to lunch boxes, soup bowls, cups, or trays.

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