Modified PET plastic bottle and preparation method thereof

Abstract

The invention relates to the technical field of packaging materials, in particular to a modified PET plastic bottle and a preparation method thereof. The invention provides a modified PET plastic bottle. The modified PET plastic bottle is prepared from the following raw materials in parts by weight: 100 parts of PET resin, 5 to 15 parts of PEFT, 3 to 10 parts of MBS, 2 to 8 parts of TPEE, 0.25 to 0.75 part of compound antioxidant, 0.05 to 0.2 part of nano talcum powder, 0.05 to 0.3 part of carboxylate nucleating agent, 0.1 to 0.3 part of oxidized rice bran wax calcium salt, 0.05 to 0.15 part of tert-butyl calcium phosphonate, a heat-resistant system and an antibacterial system, meanwhile, according to the preparation method of the modified PET plastic bottle, the product has the comprehensive excellent performance of high strength, high heat resistance, high antibacterial property and high transparency at the same time by accurately controlling technological parameters of melt reaction extrusion granulation and optimizing an injection-drawing-blowing forming technology, the technological process is simplified, and the preparation method is suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of packaging materials technology, and in particular to a modified PET plastic bottle and its preparation method. Background Technology

[0002] Polyethylene terephthalate (PET), a thermoplastic polyester material, is widely used in the packaging industry due to its excellent transparency, good processability, non-toxicity, and relatively low cost. Especially in the beverage packaging sector, PET plastic bottles have become the mainstream alternative to glass and polystyrene, widely used in cold drinks, juices, milk tea, and drinking water. PET material is not only lightweight and not easily broken, facilitating transportation and use, but also has good recycling value, aligning with the trend of green and environmentally friendly development. However, with consumption upgrades and the expansion of application scenarios, the market has placed higher demands on the comprehensive performance of PET plastic bottles, particularly in areas such as holding hot beverages, repeated use, and hygiene and safety. Traditional PET materials can no longer meet these diversified needs.

[0003] Despite the widespread use of PET plastic bottles, significant technical drawbacks remain in practical applications. First, PET material has a relatively low glass transition temperature (approximately 70-80℃). When used to hold hot liquids, such as hot coffee or tea, where temperatures typically exceed 85℃, the bottle is prone to softening and deformation, potentially leading to structural failure and severely limiting its application in hot beverage packaging. Second, while PET material possesses some toughness, its impact resistance is limited, especially in low-temperature environments or areas of stress concentration. Accidental drops or impacts can easily cause brittle fractures, resulting in leakage, resource waste, and potential safety hazards for users. Furthermore, as frequently touched drinking containers, PET plastic bottles are susceptible to bacterial growth during use and storage. Existing ordinary PET cups lack antibacterial properties, failing to meet consumers' growing demands for hygiene and safety. To address these issues, existing technologies have implemented several improvements, such as adding elastomers to enhance toughness, adding nucleating agents to increase crystallinity and improve heat resistance, or applying antibacterial coatings to impart antibacterial properties. However, these improvement solutions typically optimize only a single property, and often suffer from drawbacks: while adding rubber-based toughening agents can improve impact resistance, it often leads to a decrease in heat resistance; adding antibacterial agents (especially inorganic antibacterial particles) can easily create stress concentration points in the matrix, thus reducing mechanical strength; and while multilayer composite structures can achieve multiple properties, their manufacturing processes are complex and costly, and they also affect the transparency and recyclability of the product. Therefore, how to simultaneously achieve a synergistic improvement in impact resistance, heat resistance, and antibacterial properties in a single material system, while maintaining good transparency and processability, has become a pressing technical challenge in this field.

[0004] In view of the shortcomings of existing technologies, there is an urgent need in this field to develop a modified PET plastic bottle and its preparation method, which can combine excellent impact resistance, heat resistance and antibacterial properties with a relatively simple preparation process and good transparency, and has significant technological progress and industrial application value. Summary of the Invention

[0005] To achieve the desired effects of excellent impact resistance, heat resistance, and antibacterial properties in PET plastic bottles, while maintaining a relatively simplified manufacturing process and good transparency, this application provides a modified PET plastic bottle and its preparation method.

[0006] In a first aspect, this application provides a modified PET plastic bottle, employing the following technical solution: A modified PET plastic bottle comprises the following raw materials in parts by weight: 100 parts PET resin, 5-15 parts PEFT, 3-10 parts MBS, 2-8 parts TPEE, 0.25-0.75 parts compound antioxidant, 0.05-0.2 parts nano talc, 0.05-0.3 parts carboxylate nucleating agent, 0.1-0.3 parts oxidized rice bran wax calcium salt, and 0.05-0.15 parts tert-butylphosphonate calcium.

[0007] By adopting the above-mentioned compounding scheme, PEFT, MBS, and TPEE constitute a triple toughening mechanism. PEFT achieves chemical toughening at the molecular chain scale, MBS forms an "island structure" to absorb impact energy at the phase structure scale, and TPEE improves the matrix toughness at the continuous phase scale. The synergy of the three significantly improves the impact strength compared to conventional PET. Secondly, the furan unit in PEFT, together with oxidized rice bran wax calcium salt, tert-butylphosphonate calcium, and carboxylate nucleating agent, constructs a quadruple nucleation synergistic mechanism, achieving a crystallinity of 42-48% and a heat distortion temperature ≥108℃, while also meeting the light transmittance requirements, overcoming the problem of "toughening inevitably reducing heat resistance". Thirdly, the compounded antioxidant system ensures that the impact strength retention rate after aging is ≥85%, ensuring the long-term stability of the product. At the same time, all components have clear food contact regulations, can be directly used in the production of food contact hot beverage cups, have good process adaptability, and are suitable for industrial production.

[0008] Preferably, the PEFT is prepared by the following steps: 2,5-furandicarboxylic acid, terephthalic acid, ethylene glycol and catalyst are added to a reaction vessel in the following proportions, and an esterification reaction is carried out at 200-230°C for 2-4 hours under nitrogen protection; then the temperature is raised to 250-270°C, and a vacuum is gradually drawn to a system pressure of 50-60 Pa for a polycondensation reaction for 3-5 hours; after the reaction is completed, the vacuum is broken with nitrogen, and the melt is cooled, pelletized and dried to obtain PEFT.

[0009] Preferably, the intrinsic viscosity of the PEFT (furan dicarboxylic acid-ethylene glycol-terephthalic acid copolyester) is 0.8-0.9 dL / g, the furan unit content is basically consistent with the feed ratio with a deviation of less than 0.2 mol%, the glass transition temperature is 70-80℃, the melting temperature is 220-250℃, and the 5% thermal weight loss temperature is higher than 380℃.

[0010] Preferably, in the PEFT, 2,5-furandicarboxylic acid accounts for 1.5-4% of the total molar amount of diacid, terephthalic acid accounts for 96-98.5% of the total molar amount of diacid, and the ratio of ethylene glycol to the total molar amount of diacid is (1.3-1.8):1.

[0011] Preferably, the amount of catalyst used is 0.03-0.04% of the total mass of the diacid; the catalyst is one or more of tetrabutyl titanate and antimony glycolate.

[0012] By employing the above-mentioned scheme, the prepared PEFT copolyester incorporates furan rings into the polyester backbone. Utilizing the smaller spatial volume of furan rings compared to benzene rings, it increases molecular chain flexibility, resulting in a significant improvement in impact strength compared to conventional PET. Simultaneously, furan units act as homogeneous nucleation sites, accelerating PET crystallization and increasing the crystallization rate, breaking the technical bottleneck of traditional toughening agents that "toughening inevitably reduces heat resistance." Furthermore, it forms a dual toughening mechanism with core-shell toughening agents; the furan-containing copolyester achieves chemical toughening at the molecular chain scale, while the core-shell toughening agent achieves phase toughening. The structural scale achieves physical toughening, and the two work together to further enhance impact strength. PEFT, chain extender, and nano-montmorillonite form a triple heat resistance mechanism. The furan copolyester promotes crystallization and improves heat resistance, the chain extender chemically extends the chain to increase molecular weight, and the nano-montmorillonite physically blocks and restricts chain movement. The three work together to increase the heat distortion temperature, meeting the requirements of hot beverage packaging, while maintaining excellent transparency and being environmentally friendly and sustainable. At the same time, the PEFT prepared by this method meets the requirements of the National Health Commission. Its specific migration amounts are ≤5 mg / kg for 2,5-furandicarboxylic acid, ≤30 mg / kg for ethylene glycol, and ≤6 mg / kg for acetaldehyde, which can be used for hot filling, pasteurization, or other heat treatment scenarios.

[0013] Preferably, the MBS has a particle size of 100-300 nm.

[0014] By adopting the above scheme, MBS is a copolymer of methyl methacrylate-butadiene-styrene, with butadiene rubber as the core layer to provide toughness and methyl methacrylate as the shell layer, which has good compatibility with PET. The particle size is 100-300nm, which is smaller than the wavelength of visible light and does not affect the transparency.

[0015] Preferably, the compound antioxidant comprises the following raw materials in parts by weight: 0.1-0.4 parts of hindered phenolic antioxidant, 0.1-0.2 parts of phosphite antioxidant, and 0.05-0.15 parts of polyethylene glycol monooleate.

[0016] Preferably, the hindered phenolic antioxidant is either antioxidant 1010 or antioxidant 1076.

[0017] Preferably, the phosphite antioxidant is antioxidant 168.

[0018] By employing the above-mentioned compound antioxidant scheme, a dual synergistic mechanism of "antioxidant-dispersion" is constructed: hindered phenolic antioxidants capture free radicals, phosphite antioxidants decompose hydrogen peroxide to form a classic synergistic protection, and polyethylene glycol monooleate plays the role of antioxidant synergist and dispersant, thereby improving the uniformity of antioxidant dispersion and melt flowability. Moreover, all components comply with the requirements of Chinese GB 9685-2016 and EU (EU) 2026 / 245 regulations, ensuring food safety compliance of the product under 100°C hot filling conditions.

[0019] Preferably, the nano-talc powder is between 12,000 mesh and 30,000 mesh.

[0020] Preferably, the modified PET plastic bottle further includes a heat-resistant system comprising the following raw materials in parts by weight: 0.3-1.5 parts of epoxy functionalized polymer chain extender, 0.5-1.0 parts of modified montmorillonite, and 0.3-0.6 parts of SEBS-g-MA graft.

[0021] The SEBS-g-MA is a maleic anhydride-grafted styrene-ethylene-butadiene-styrene copolymer with a grafting rate of 1.5-2.5%.

[0022] By adopting the above scheme, the epoxy chain extender reacts with the PET end groups to increase the molecular weight and melt strength, the modified montmorillonite forms a nanoscale "maze structure" to physically restrict the thermal movement of molecular chains, and the SEBS-g-MA graft participates in the construction of an organic-inorganic hybrid heat-resistant network through chemical bonding. The synergy of the three factors significantly improves the heat distortion temperature compared with the basic formula, while also increasing the impact strength.

[0023] Preferably, the modified montmorillonite includes the following steps: adding 100 parts of sodium montmorillonite and 30-42 parts of cetyltrimethylammonium bromide to a high-speed mixer and dry mixing at room temperature for 5-10 minutes to ensure thorough and uniform mixing; then feeding the mixture into a twin-screw extruder for melt intercalation treatment, with the extrusion temperature controlled at 120-150℃, the screw speed at 200-400 rpm, and the residence time at 2-5 minutes; the extruded material is cooled, granulated, crushed, and passed through a 200-mesh sieve to obtain the modified montmorillonite.

[0024] By employing the above-mentioned method, the prepared modified montmorillonite exhibits an increased interlayer spacing of 2.2-2.8 nm, achieving nanoscale dispersion within the PET matrix. It forms a dual heat-resistant mechanism of chemical chain extension and physical barrier with the chain extender, thereby increasing the heat distortion temperature. Furthermore, it forms a multi-scale toughening and auxiliary reinforcement mechanism with PEFT and core-shell toughening agents, enhancing impact strength. Simultaneously, the "maze effect" of the montmorillonite layers significantly reduces oxygen permeability, substantially extending the shelf life of the contents. Moreover, the heterogeneous nucleation effect of montmorillonite, synergistically with the nucleating agent, refines the grain size, maintaining high transparency of the product while improving crystallinity.

[0025] Preferably, the modified PET plastic bottle further includes an antibacterial system consisting of 0.3-1.0 parts of zinc-loaded nano-zeolite.

[0026] Preferably, in the antibacterial system, stearic acid, accounting for 1-3% of the total mass of the antibacterial system, is added as a dispersant.

[0027] By adopting the above scheme, zinc-loaded nano-zeolite was used to achieve highly efficient and broad-spectrum antibacterial properties: the three-dimensional structure of the zeolite slowly releases Zn. 2+ Zinc ions, through multiple synergistic mechanisms such as disrupting bacterial cell membranes, inducing reactive oxygen species enrichment, and interfering with arginine synthesis, can achieve antibacterial rates of over 99.0% against Escherichia coli and Staphylococcus aureus. Zinc-loaded zeolite appears as a white powder, has good compatibility with the PET matrix, has little impact on the transparency of the product, and exhibits high thermal stability, allowing it to withstand PET processing temperatures. Stearic acid, as a dispersant, effectively prevents the agglomeration of nano-zeolite, ensuring its uniform dispersion in the polymer.

[0028] Secondly, this application provides a method for preparing a modified PET plastic bottle, which includes the following steps: S1 Blending Granulation: PET resin, PEFT, MBS, TPEE, compound antioxidant, nano talc, carboxylate nucleating agent, oxidized rice bran wax calcium salt and tert-butylphosphonate calcium are added to a high-speed mixer and mixed evenly; the mixture is fed into a twin-screw extruder for melt reaction extrusion granulation; the extruded material is cooled, air-dried and pelletized to obtain modified PET composition granules; S2 Injection-Stretch-Blow Molding: The modified PET composition granules obtained in step S1 are injection molded into preforms using an injection molding machine at an injection temperature of 250-270℃, an injection pressure of 60-90MPa, and a mold temperature of 20-40℃. The injection-molded preforms are then heated in a furnace to 90-105℃ to ensure uniform temperature. The heated preforms are then fed into a blow molding die for biaxial stretch blow molding, controlling the axial stretch ratio to be (2.8-3.2):1 and the radial stretch ratio to be (3.2-3.8):1. The blow molding die temperature is controlled at 100-120℃, and the blow molding pressure is 2.5-4.0MPa. After cooling and setting, modified PET plastic bottles are obtained.

[0029] Preferably, in step S1, the extrusion granulation is carried out with the following extrusion temperatures from the feeding section to the die head: feeding section 220-240℃, conveying section 240-250℃, melting section 250-260℃, mixing section 250-260℃, metering section 245-255℃, and die head 245-255℃; screw speed 300-500 rpm, residence time 2 minutes.

[0030] Preferably, the modified PET composition granules in step S2 are dried at 125-130°C for 4-5 hours until the moisture content is below 50 ppm, and then injection molded into tube blanks.

[0031] Preferably, the method for preparing the modified PET plastic bottle further includes adding an antibacterial system and a heat-resistant system, premixing the modified montmorillonite with a portion of the PET resin in a high-speed mixer for 5 minutes to allow the montmorillonite to initially adhere to the surface of the PET resin, thereby obtaining a montmorillonite premix, and then mixing the epoxy functionalized polymer chain extender, SEBS-g-MA graft, zinc-loaded nano-zeolite, and stearic acid in a high-speed mixer; and then adding the remaining PET resin and other components together in a high-speed mixer for blending and granulation.

[0032] Preferably, the modified montmorillonite and a portion of the PET resin are mixed at a mass ratio of 1:(3-5).

[0033] By adopting the above scheme, the modified montmorillonite is premixed with a portion of PET resin in a certain proportion, so that the montmorillonite flakes are initially attached to the surface of the PET resin, avoiding the agglomeration phenomenon when nanoparticles are directly added, and enabling the montmorillonite to achieve nanoscale dispersion in subsequent melt blending.

[0034] By adopting the above scheme, this invention simplifies the preparation process of modified PET plastic bottles and comprehensively improves their performance: the S1 blending and granulation step ensures that all components are fully melted and uniformly dispersed by precisely controlling the extrusion temperature and screw speed; the S2 injection-stretch-blow molding promotes the bidirectional orientation and high-temperature crystallization of PET molecular chains by optimizing the injection temperature, stretch ratio, and blow mold temperature; in the preferred antibacterial and heat-resistant system addition scheme, modified montmorillonite is premixed with a portion of PET resin to obtain montmorillonite premix, which is then mixed stepwise with chain extender and antibacterial agent. Through a gradient dispersion mechanism, the nanoscale dispersion of montmorillonite and the uniform distribution of antibacterial agent are achieved. Under the simplified process conditions that do not require masterbatch preparation, the product simultaneously possesses high antibacterial properties, high heat resistance, and high transparency, exhibiting excellent comprehensive performance, simplified process flow, reduced energy consumption, and significant industrial application value.

[0035] In summary, this application has the following beneficial effects: 1. The modified PET plastic bottle prepared in this application achieves chemical toughening through a triple toughening mechanism composed of PEFT, MBS, and TPEE: PEFT increases the flexibility of chain segments at the molecular chain scale to achieve chemical toughening; MBS forms an "island structure" at the phase structure scale to absorb impact energy; and TPEE improves the toughness of the matrix at the continuous phase scale. The three work synergistically at different scales. At the same time, the furan unit in PEFT, together with oxidized rice bran wax calcium salt, tert-butylphosphonate calcium, and carboxylate nucleating agents, constitutes a multi-nucleation synergistic mechanism, achieving a unity of high impact resistance, high heat resistance, and high transparency, thus meeting the requirements of hot beverage packaging.

[0036] 2. The compound antioxidant of this application consists of a dual synergistic system of "antioxidant-dispersion" composed of hindered phenolic antioxidants, phosphite antioxidants, and polyethylene glycol monooleate: the hindered phenolic antioxidants capture free radicals to terminate the oxidation chain reaction, the phosphite antioxidants decompose hydrogen peroxide, and the polyethylene glycol monooleate simultaneously functions as an antioxidant synergist and dispersant, thereby improving the uniformity of antioxidant dispersion; the heat-resistant system constructs a triple synergistic mechanism of "chemical chain extension-physical barrier-elastomer toughening" through epoxy functionalized polymer chain extenders, modified montmorillonite, and SEBS-g-MA grafts, thereby increasing the heat distortion temperature compared to the basic formulation; the antibacterial system achieves an antibacterial rate of over 99% against Escherichia coli and Staphylococcus aureus through the zinc ion slow-release antibacterial mechanism of zinc-loaded nano-zeolite, and the zinc migration meets the EU safety requirement of ≤5 mg / kg for food.

[0037] 3. The preparation method of this application ensures uniform dispersion of each component by precisely controlling the process parameters of melt reaction extrusion granulation; by optimizing the injection-stretch-blow molding process, it promotes the bidirectional orientation and high-temperature crystallization of PET molecular chains, so that the product has comprehensive excellent properties of high strength, high heat resistance, high antibacterial and high transparency. Moreover, the process flow is simplified and suitable for industrial production. Detailed Implementation

[0038] The technical solution of this application is further illustrated by specific embodiments below. These specific embodiments do not represent a limitation on the scope of protection of this application. Any non-essential modifications and adjustments made by others based on the concept of this application still fall within the scope of protection of this application.

[0039] Unless otherwise specified, the experimental methods shown in the following examples are conventional methods. All reagents and materials shown are commercially available products.

[0040] PET resin (polyethylene terephthalate resin): Hainan Yisheng Petrochemical Co., Ltd., production batch number: H8-Y01-250103; 2,5-Furandicarboxylic acid: Zhongshan Dixin Chemical Co., Ltd., CAS: 3238-40-2, Purity: 98.0%; Terephthalic acid: Shanghai Aladdin Biochemical Technology Co., Ltd., CAS: 100-21-0, No.: 7489; Ethylene glycol: Tianjin Zhonghe Shengtai Chemical Co., Ltd., CAS: 107-21-1, Model: 001-1; Tetrabutyl titanate: Jinan Jinbang Industrial Technology Co., Ltd., CAS: 5593-70-4, Item No.: C72; Antimony glycol: Jiangsu Puleisi Biotechnology Co., Ltd., CAS: 29736-75-2, Model: P836404; MBS (Methyl methacrylate-butadiene-styrene copolymer): Zhejiang Longhua Plastic Additives Co., Ltd., batch number: M-51A; TPEE: DuPont (USA), Model: Hytrel 3078FG S30D; Antioxidant 1010: Shanghai Aladdin Biochemical Technology Co., Ltd., CAS: 6683-19-8, No.: 64819; Antioxidant 1076: Shanghai Aladdin Biochemical Technology Co., Ltd., CAS: 2082-79-3, No.: 16386; Antioxidant 168: Shanghai Aladdin Biochemical Technology Co., Ltd., CAS: 31570-04-4, No.: 91601; Nano talc powder: Shenzhen Luyue Powder Technology Co., Ltd., CAS: 14807-96-6, Item No.: LY-T series, Specifications: 12000 mesh, 17000 mesh, 30000 mesh; Carboxylate nucleating agent: DuPont Surlyn resin, CAS: 465789, product model: Surlyn 8920; Epoxy functionalized polymer chain extender: Beijing Huarui Xincheng Technology Co., Ltd., product model: KL-E4370; Oxidized rice bran wax calcium salt: Clariant Chemicals (Shanghai) Co., Ltd., Licocare™, Model: RBW 101powder Vita; tert-Butylphosphonic acid: Shanghai Yuanye Biotechnology Co., Ltd., Product No.: Y37671-1g; Polyethylene glycol monooleate: Guangdong Shengke Biochemical Technology Co., Ltd., CAS: 9004-96-0, Item No.: pgm8-20; SEBS-g-MA graft: Kertész Polymer Trading (Shanghai) Co., Ltd., Model: G1901G, Grafting rate 1.4-2.0%; Sodium-based montmorillonite: Jiangsu Xianfeng Nanomaterials Technology Co., Ltd., Product Name: Nanocor Inorganic Montmorillonite; Hexadecyltrimethylammonium bromide: Henan Youmei Chemical Products Co., Ltd., CAS: 7-09-0, Item No.: 140ym; Zinc-loaded nano-zeolite: Guangzhou Jingao New Material Technology Co., Ltd., Product Name: Inorganic Zinc Ion Antibacterial Agent JA-8620.

[0041] The present application will be further described in detail below with reference to embodiments and comparative examples.

[0042] Preparation Example Preparation Example 1: Preparation of PEFT 2.34 kg (0.015 kmol) of 2,5-furandicarboxylic acid, 163.67 kg (0.985 kmol) of terephthalic acid, and 93.15 kg (1.50 kmol) of ethylene glycol were added to a reactor, wherein 2,5-furandicarboxylic acid accounted for 1.5% of the total molar amount of the diacids, and the ratio of ethylene glycol to the total molar amount of the diacids was 1.5:1. 0.06 kg of antimony glycol (0.036% of the total mass of the diacids) was added. The mixture underwent esterification at 200°C for 4 hours under nitrogen protection, then the temperature was raised to 250°C, and a vacuum was gradually applied until the system pressure was below 60 Pa for polycondensation reaction for 5 hours. After the reaction, the vacuum was broken with nitrogen, the melt was cooled, pelletized, and vacuum dried at 120°C for 6 hours to obtain PEFT. The intrinsic viscosity of the obtained PEFT was 0.88. It has a dL / g, a glass transition temperature of 78℃, a melting temperature of 242℃, and a 5% thermal weight loss temperature of 390℃.

[0043] Preparation Example 2: Preparation of PEFT 3.90 kg (0.025 kmol) of 2,5-furandicarboxylic acid, 161.95 kg (0.975 kmol) of terephthalic acid, and 93.15 kg (1.50 kmol) of ethylene glycol were added to a reactor, with 2,5-furandicarboxylic acid accounting for 2.5% of the total molar amount of the diacids, and the ratio of ethylene glycol to the total molar amount of the diacids being 1.5:1. 0.05 kg of tetrabutyl titanate (0.03% of the total mass of the diacids) was added. The mixture was subjected to esterification at 220°C for 3 hours under nitrogen protection, then the temperature was raised to 260°C, and a vacuum was gradually applied until the system pressure was below 50 Pa for polycondensation reaction for 3.5 hours. After the reaction, the vacuum was broken with nitrogen, the melt was cooled, pelletized, and vacuum dried at 120°C for 6 hours to obtain PEFT. The intrinsic viscosity of the obtained PEFT was 0.85. It has a dL / g, a glass transition temperature of 76℃, a melting temperature of 238℃, and a 5% thermal weight loss temperature of 392℃.

[0044] Preparation Example 3: Preparation of PEFT 6.24 kg (0.04 kmol) of 2,5-furandicarboxylic acid, 159.46 kg (0.96 kmol) of terephthalic acid, and 111.726 kg (1.80 kmol) of ethylene glycol were added to a reactor, wherein 2,5-furandicarboxylic acid accounted for 4.0% of the total molar amount of the diacids, and the ratio of ethylene glycol to the total molar amount of the diacids was 1.8:1. 0.03 kg of tetrabutyl titanate and 0.03 kg of antimony glycol ethylene (a compound catalyst, accounting for 0.036% of the total mass of the diacids) were added. The esterification reaction was carried out at 230°C for 2 hours under nitrogen protection, then the temperature was raised to 270°C, and the system pressure was gradually evacuated to below 50 Pa for polycondensation reaction for 3 hours. After the reaction, the vacuum was broken with nitrogen, the melt was cooled, pelletized, and vacuum dried at 120°C for 6 hours to obtain PEFT. The intrinsic viscosity of the obtained PEFT was 0.82. It has a dL / g, a glass transition temperature of 74℃, a melting temperature of 232℃, and a 5% thermal weight loss temperature of 388℃.

[0045] Preparation Example 4: Preparation of PEFT 6.24 kg (0.04 kmol) of 2,5-furandicarboxylic acid, 159.46 kg (0.96 kmol) of terephthalic acid, and 80.691 kg (1.50 kmol) of ethylene glycol were added to a reactor, with 2,5-furandicarboxylic acid accounting for 4.0% of the total molar amount of the diacids, and the ratio of ethylene glycol to the total molar amount of the diacids being 1.3:1. 0.04 kg of tetrabutyl titanate (0.04% of the total diacid mass) was added. The reaction was carried out under nitrogen protection at 225°C for 2.8 hours, followed by heating to 262°C and gradually evacuating the system until the pressure was below 50 Pa, for a polycondensation reaction of 3.2 hours. After the reaction, the vacuum was broken with nitrogen, the melt was cooled, pelletized, and vacuum dried at 120°C for 6 hours to obtain PEFT. The intrinsic viscosity of the obtained PEFT was 0.85. It has a dL / g, a glass transition temperature of 72℃, a melting temperature of 230℃, and a 5% thermal weight loss temperature of 383℃.

[0046] Preparation Example 5: Preparation of Modified Montmorillonite 10 kg of sodium montmorillonite and 3 kg of cetyltrimethylammonium bromide were added to a high-speed mixer and dry-mixed at room temperature for 5 minutes to ensure thorough and uniform mixing. The mixture was then fed into a twin-screw extruder for melt intercalation, with the extrusion temperature controlled at 120°C, the screw speed at 200 rpm, and the residence time at 2 minutes. The extruded material was cooled, granulated, crushed, and passed through a 200-mesh sieve to obtain modified montmorillonite.

[0047] Preparation Example 6: Preparation of Modified Montmorillonite 10 kg of sodium montmorillonite and 3.6 kg of cetyltrimethylammonium bromide were added to a high-speed mixer and dry-mixed at room temperature for 8 minutes to ensure thorough and uniform mixing. The mixture was then fed into a twin-screw extruder for melt intercalation, with the extrusion temperature controlled at 135°C, the screw speed at 300 rpm, and the residence time at 3.5 minutes. The extruded material was cooled, granulated, crushed, and passed through a 200-mesh sieve to obtain modified montmorillonite.

[0048] Preparation Example 7: Preparation of Modified Montmorillonite 10 kg of sodium montmorillonite and 4.2 kg of cetyltrimethylammonium bromide were added to a high-speed mixer and dry-mixed at room temperature for 10 minutes to ensure thorough and uniform mixing. The mixture was then fed into a twin-screw extruder for melt intercalation, with the extrusion temperature controlled at 150°C, the screw speed at 400 rpm, and the residence time at 5 minutes. The extruded material was cooled, granulated, crushed, and passed through a 200-mesh sieve to obtain modified montmorillonite.

[0049] Preparation Example 8: Preparation of calcium tert-butylphosphonate 92.07 g of tert-butylphosphonic acid was dissolved in a mixed solvent of 500 mL deionized water and 200 mL anhydrous ethanol and heated to 80 °C in a water bath. 37.80 g of calcium hydroxide was dissolved in 100 mL deionized water. Under constant temperature and stirring at 80 °C, the calcium hydroxide suspension was rapidly added dropwise to the tert-butylphosphonic acid solution at a rate of 10 mL / min over approximately 25 minutes. The pH was adjusted to 8.0 ± 0.2 using 1 mol / L sodium hydroxide solution. After the addition was complete, the reaction system was heated to 85 °C and stirred for 2 hours. Then, stirring was stopped, and the mixture was allowed to stand at 85 °C for 1 hour to age. After naturally cooling to room temperature, the mixture was vacuum filtered, and the white precipitate filter cake was collected. The filter cake was washed three times with hot deionized water at 80℃ until the pH of the washing solution reached 7.0. The washed filter cake was then placed in a vacuum drying oven and dried at a vacuum of -0.09MPa and 90℃ for 12 hours until constant weight was achieved. The dried product was then pulverized and sieved to obtain a white powder of calcium tert-butylphosphonate.

[0050] Example

[0051] Example 1 A method for preparing a modified PET plastic bottle, comprising the following technical solution: S1 Blending Granulation: PET resin, PEFT, MBS, polyester elastomer, compounded antioxidant, nano talc, carboxylate nucleating agent, oxidized rice bran wax calcium salt, and tert-butylphosphonate calcium are added to a high-speed mixer and mixed evenly. The mixture is then fed into a twin-screw extruder for melt reaction extrusion granulation. The extrusion temperatures from the feeding section to the die head are as follows: feeding section 220℃, conveying section 240℃, melting section 250℃, mixing section 250℃, metering section 245℃, and die head 245℃. The screw speed is 300 rpm, and the residence time is 2 minutes. The extruded molten material is cooled in a water tank to reduce the temperature of the strip to 50℃. Then, it is air-dried by a blower (wind speed 8m / s) to remove surface moisture, and then pelletized by a pelletizer (pelletizing speed 500 rpm) to obtain modified PET composition pellets with a length of 3mm. S2 Injection-Stretch-Blow Molding: The modified PET composition granules obtained in step S1 are injection molded into preforms using an injection molding machine at an injection temperature of 250℃, an injection pressure of 90MPa, and a mold temperature of 20℃. The injection-molded preforms are then heated in a furnace to 90℃ to ensure uniform temperature. The heated preforms are then fed into a blow molding die for biaxial stretch blow molding, controlling the axial stretch ratio at 2.8:1 and the radial stretch ratio at 3.2:1. The blow molding die temperature is controlled at 100℃, and the blow molding pressure is 4.0MPa. After cooling and setting, modified PET plastic bottles are obtained.

[0052] The component amounts used in the blending granulation are shown in Table 1, and the processing parameters in the preparation method are shown in Table 2.

[0053]

[0054] The PEFT was prepared according to the preparation method of Example 1; the calcium tert-butylphosphonate was prepared according to the preparation method of Example 8, and the nano-talc powder was 12000 mesh.

[0055] Example 2 The difference from Example 1 is that the composition and amount of the modified PET plastic bottle are shown in Table 1, and the processing conditions are shown in Table 2; the PEFT is prepared according to the preparation method of Example 2; and the average particle size of the nano talc powder is 17,000 mesh.

[0056] Example 3 The difference from Example 1 is that the composition and amount of the modified PET plastic bottle are shown in Table 1, and the processing conditions are shown in Table 2; the PEFT is prepared according to the preparation method of Example 2; and the average particle size of the nano talc powder is 17,000 mesh.

[0057] Example 4 The difference from Example 1 is that the composition and amount of the modified PET plastic bottle are shown in Table 1, and the processing conditions are shown in Table 2; the PEFT is prepared according to the scheme of Preparation Example 3; and the average particle size of the nano talc powder is 12000 mesh.

[0058] Example 5 The difference from Example 1 is that the composition and amount of the modified PET plastic bottle are shown in Table 1, and the processing conditions are shown in Table 2; the PEFT is prepared according to the scheme of Preparation Example 4; and the average particle size of the nano talc powder is 30,000 mesh.

[0059] Example 6 The difference from Example 3 is that the preparation method of the modified PET plastic bottle also includes a heat-resistant system and an antibacterial system: the modified montmorillonite and a portion of PET resin are premixed in a high-speed mixer for 5 minutes at a speed of 1200 rpm, so that the montmorillonite initially adheres to the surface of the PET resin to obtain a montmorillonite premix. Then, the epoxy functionalized polymer chain extender, SEBS-g-MA graft, zinc-loaded nano-zeolite, stearic acid, the remaining PET resin and other components are added to the high-speed mixer for blending and granulation.

[0060] The component amounts used in the blending granulation are shown in Table 3:

[0061] Examples 7-14 The difference from Example 6 is that the component amounts in the blending granulation are shown in Table 3.

[0062] Comparative Example Comparative Example 1 The difference from Example 3 is that PEFT is not added, and MBS and TPEE remain unchanged.

[0063] Comparative Example 2 The difference from Example 3 is that MBS is not added, while PEFT and TPEE remain unchanged.

[0064] Comparative Example 3 The difference from Example 3 is that TPEE is not added, while PEFT and MBS remain unchanged.

[0065] Comparative Example 4 The difference from Example 3 is that no compound antioxidant is added.

[0066] Comparative Example 5 The difference from Example 3 is that no carboxylate nucleating agent is added, and the amount of nano-talc powder added remains unchanged.

[0067] Comparative Example 6 The difference from Example 3 is that no nano-talc powder is added, and the amount of carboxylate nucleating agent remains unchanged.

[0068] Comparative Example 7 The difference from Example 13 is that no modified montmorillonite was added, but only 0.9 kg of epoxy functionalized polymer chain extender was added.

[0069] Comparative Example 8 The difference from Example 13 is that no epoxy functionalized polymer chain extender is added, only 0.8 kg of modified montmorillonite is added.

[0070] Comparative Example 9 The difference from Example 13 is that no carboxylate nucleating agent, oxidized rice bran wax calcium salt, and tert-butylphosphonate calcium are added, while other components and preparation methods remain unchanged.

[0071] Comparative Example 10 The difference from Example 13 is that no SEBS-g-MA graft is added, while the other components and preparation method remain unchanged.

[0072] Performance testing The modified PET plastic bottles prepared in Examples 1-14 and Comparative Examples 1-10 were subjected to performance tests using the following methods, and the test conditions are shown in Table 4.

[0073]

[0074] The modified PET plastic bottles prepared by the methods of Examples 1-14 and Comparative Examples 1-10 were subjected to the above performance tests, and the test results are shown in Table 5.

[0075]

[0076] As shown in Table 5, the performance test results of Examples 1-5 fully demonstrate the superiority of the toughening system of this invention. Among them, Example 3 exhibits the best overall performance, with an impact strength of 16.2 kJ / m², a heat distortion temperature of 104℃, a crystallinity of 38%, a haze of 6.3%, a light transmittance of 89.5%, and an impact retention rate of 85% after aging. This indicates that PEFT, MBS, and TPEE, in a ratio of 10:6:5, form a triple toughening mechanism. PEFT increases chain segment flexibility at the molecular chain scale, MBS forms an "island structure" at the phase structure scale to absorb impact energy, and TPEE improves the toughness of the matrix at the continuous phase scale. The three work synergistically to maximize the toughening effect. At the same time, the three-level protection system of compound antioxidants effectively prevents thermal degradation during processing, ensuring long-term stability. The compound nucleating agent refines the grain size while increasing the crystallization rate, achieving a balance between high heat resistance and high transparency.

[0077] Examples 6-14 fully demonstrate the synergistic effect of the antibacterial and heat-resistant systems. Among them, Example 13 exhibits the best overall performance, with a heat distortion temperature of 109℃, an antibacterial rate of 99.3%, an impact strength of 15.5 kJ / m², a haze of 6.9%, a light transmittance of 89.0%, and an impact retention rate of 87% after aging. This indicates that when the antibacterial and heat-resistant systems are combined at an intermediate value, they impart excellent antibacterial and heat-resistant properties to the product while maintaining good mechanical properties and transparency.

[0078] Examples 6-8 show the addition of an antibacterial system alone, while Example 7 shows an antibacterial rate of 99.3% and an impact strength of 15.6 kJ / m², making it the preferred antibacterial system.

[0079] Examples 9-11 show that the heat-resistant system is added alone. The epoxy functionalized polymer chain extender reacts with the PET end groups to increase the molecular weight, and the modified montmorillonite restricts the thermal motion of the molecular chain through physical barriers. The two work synergistically to significantly increase the heat distortion temperature. Example 10 shows a heat distortion temperature of 109℃ and an impact strength of 15.8 kJ / m², which is the preferred solution for the heat-resistant system.

[0080] Examples 12-14 combine antibacterial and heat-resistant systems, resulting in excellent overall performance; Example 13 has a heat distortion temperature of 109℃, an antibacterial rate of 99.3%, and an impact strength of 15.5 kJ / m², with all indicators being optimally balanced.

[0081] In Comparative Example 1, without the addition of PEFT, the impact strength decreased to 8.5 kJ / m², and the heat distortion temperature was 98℃. This indicates that the chemical toughening mechanism of PEFT is the core of the triple toughening. It introduces furan units through copolymerization to increase the flexibility of the molecular chain. At the same time, the homogeneous nucleation effect of furan units promotes crystallization, avoiding the "seesaw effect" of heat resistance reduction caused by traditional toughening agents. Without PEFT, the physical toughening of MBS and TPEE alone cannot achieve the desired effect.

[0082] Comparative Example 2, without the addition of MBS, showed that the impact strength dropped to 10.2 kJ / m², indicating that the core-shell structure toughening mechanism of MBS is indispensable. MBS forms a nanoscale "island structure" in the PET matrix, which acts as a stress concentration point to induce crazing and shear bands to absorb impact energy. Its 200nm particle size is smaller than the wavelength of visible light, achieving toughening without affecting transparency.

[0083] Comparative Example 3, without the addition of TPEE, showed that the impact strength decreased to 12.5 kJ / m², indicating that the elastomeric toughening mechanism of TPEE has an auxiliary reinforcing effect. As a polyether ester block copolymer, TPEE has hard segments that are compatible with PET and soft segments that provide elasticity, further improving the matrix toughness at the continuous phase level, and forming a complete multi-scale toughening network with PEFT and MBS.

[0084] Comparative Example 4, without the addition of compound antioxidants, showed a decrease in heat distortion temperature to 98℃, a decrease in impact retention rate after aging to 52%, and an increase in haze to 8.5%. This indicates that the three-level protection system of compound antioxidants is key to preventing processing thermal degradation and long-term aging. Hindered phenolic antioxidants capture free radicals, while phosphite antioxidants decompose peroxides, synergistically ensuring the long-term stability of the material.

[0085] Comparative Example 5, without the addition of carboxylate nucleating agent, showed a decrease in heat distortion temperature to 92℃, a decrease in crystallinity to 28%, and an increase in haze to 8.2%, demonstrating the core role of carboxylate nucleating agent in improving heat resistance and maintaining transparency.

[0086] Comparative Example 6, without the addition of nano talc, showed a decrease in heat distortion temperature to 100℃ and crystallinity to 34%, indicating the nucleation-aiding effect of nano talc. Talc provides a large number of heterogeneous nucleation sites, which, in synergy with carboxylate nucleating agents, further improve the crystallization rate and crystallinity.

[0087] Comparative Example 7, without the addition of modified montmorillonite, showed a heat distortion temperature reduced to 106℃, indicating that the physical barrier effect of modified montmorillonite contributes synergistically to heat resistance. The montmorillonite sheets form a "maze structure" in the PET matrix, which works synergistically with the chemical chain-extending effect of the chain extender to maximize heat resistance.

[0088] Comparative Example 8, without the addition of epoxy functionalized polymer chain extender, showed a heat distortion temperature reduced to 105℃, indicating that the chemical chain-extending effect of the chain extender is the core contribution to heat resistance.

[0089] Comparative Example 9, without the addition of carboxylate nucleating agent, oxidized rice bran wax calcium salt, and tert-butylphosphonate calcium, showed a decrease in heat distortion temperature to 104℃, crystallinity to 34%, haze to 8.2%, and transmittance to 87.5%. This indicates that the complex nucleation system composed of carboxylate nucleating agent, oxidized rice bran wax calcium salt, and tert-butylphosphonate calcium is a key component of the four-fold nucleation mechanism. These three components, synergistically with the PEFT furan unit agent, significantly improve crystallinity and refine grain size, maintaining transparency while enhancing heat resistance. Without these components, relying solely on the PEFT furan unit and nano-talc significantly weakens the nucleation effect and noticeably increases haze.

[0090] Comparative Example 10, without the addition of SEBS-g-MA graft, showed a decrease in impact strength to 14.8 kJ / m² and heat distortion temperature to 106℃. This indicates that the SEBS-g-MA graft plays a crucial role in the heat-resistant system: its maleic anhydride groups react with the PET end groups to form chemical bonds, and the elastomer segments participate in the construction of an organic-inorganic hybrid heat-resistant network, forming a triple synergistic mechanism of "chemical chain extension - physical barrier - elastomer toughening" with epoxy chain extenders and modified montmorillonite. Without the graft, both heat resistance and toughness decreased when relying solely on chain extenders and montmorillonite.

[0091] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the present invention, they are protected by patent law.

Claims

1. A modified PET plastic bottle, characterized in that, The raw materials include the following parts by weight: 100 parts PET resin, 5-15 parts PEFT, 3-10 parts MBS, 2-8 parts TPEE, 0.25-0.75 parts compound antioxidant, 0.05-0.2 parts nano talc, 0.05-0.3 parts carboxylate nucleating agent, 0.1-0.3 parts oxidized rice bran wax calcium salt, and 0.05-0.15 parts tert-butylphosphonate calcium.

2. The modified PET plastic bottle according to claim 1, characterized in that, The PEFT is prepared by the following steps: 2,5-furandicarboxylic acid, terephthalic acid, ethylene glycol and catalyst are added to a reaction vessel in the following proportions, and an esterification reaction is carried out at 200-230℃ for 2-4 hours under nitrogen protection; then the temperature is raised to 250-270℃, and the system pressure is gradually evacuated to 50-60 Pa, and a polycondensation reaction is carried out for 3-5 hours; after the reaction is completed, the vacuum is broken with nitrogen, and the melt is cooled, pelletized and dried to obtain PEFT.

3. The modified PET plastic bottle according to claim 2, characterized in that, In the PEFT, 2,5-furandicarboxylic acid accounts for 1.5-4% of the total molar amount of diacid, terephthalic acid accounts for 96-98.5% of the total molar amount of diacid, and the ratio of ethylene glycol to the total molar amount of diacid is (1.3-1.8):

1.

4. The modified PET plastic bottle according to claim 2, characterized in that, The amount of catalyst used is 0.03-0.04% of the total mass of the diacid; the catalyst is one or more of tetrabutyl titanate and antimony glycolate.

5. The modified PET plastic bottle according to claim 1, characterized in that, The compound antioxidant comprises the following raw materials in parts by weight: 0.1-0.4 parts of hindered phenolic antioxidant, 0.1-0.2 parts of phosphite antioxidant, and 0.05-0.15 parts of polyethylene glycol monooleate.

6. The modified PET plastic bottle according to claim 1, characterized in that, The modified PET plastic bottle also includes a heat-resistant system comprising the following raw materials in parts by weight: 0.3-1.5 parts of epoxy functionalized polymer chain extender, 0.5-1.0 parts of modified montmorillonite, and 0.3-0.6 parts of SEBS-g-MA graft.

7. The modified PET plastic bottle according to claim 1, characterized in that, The modified PET plastic bottle also includes an antibacterial system consisting of 0.3-1.0 parts of zinc-loaded nano-zeolite.

8. A method for preparing a modified PET plastic bottle as described in any one of claims 1-7, characterized in that, It includes the following steps: S1 Blending Granulation: PET resin, PEFT, MBS, TPEE, compound antioxidant, nano talc, carboxylate nucleating agent, oxidized rice bran wax calcium salt and tert-butylphosphonate calcium are added to a high-speed mixer and mixed evenly; the mixture is fed into a twin-screw extruder for melt reaction extrusion granulation; the extruded material is cooled, air-dried and pelletized to obtain modified PET composition granules; S2 Injection-Stretch-Blow Molding: The modified PET composition granules obtained in step S1 are injection molded into preforms using an injection molding machine at an injection temperature of 250-270℃, an injection pressure of 60-90MPa, and a mold temperature of 20-40℃. The injection-molded preforms are then heated in a furnace to 90-105℃ to ensure uniform temperature. The heated preforms are then fed into a blow molding die for biaxial stretch blow molding, controlling the axial stretch ratio to be (2.8-3.2):1 and the radial stretch ratio to be (3.2-3.8):

1. The blow molding die temperature is controlled at 100-120℃, and the blow molding pressure is 2.5-4.0MPa. After cooling and setting, modified PET plastic bottles are obtained.

9. The method for preparing the modified PET plastic bottle according to claim 8, characterized in that: It also includes the addition of antibacterial and heat-resistant systems. Modified montmorillonite and a portion of PET resin are premixed in a high-speed mixer for 5 minutes to allow the montmorillonite to initially adhere to the surface of the PET resin, thus obtaining a montmorillonite premix. Then, epoxy functionalized polymer chain extender, SEBS-g-MA graft, zinc-loaded nano-zeolite, and stearic acid are mixed in a high-speed mixer. Finally, the remaining PET resin and other components are added to the high-speed mixer for blending and granulation.

10. The method for preparing the modified PET plastic bottle according to claim 8, characterized in that, In step S1, melt reaction extrusion granulation, the extrusion temperature from the feeding section to the die head is as follows: feeding section 220-240℃, conveying section 240-250℃, melting section 250-260℃, mixing section 250-260℃, metering section 245-255℃, die head 245-255℃; screw speed 300-500 rpm, residence time 2 minutes.

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