High-barrier PET (Polyethylene Terephthalate) composite material as well as preparation method and application thereof

Abstract

The invention relates to the field of high-barrier PET composite materials, in particular to a high-barrier PET composite material as well as a preparation method and application thereof. The high-barrier PET composite material is prepared from the following raw materials in parts by mass: 80 to 90 parts of polyethylene glycol terephthalate, 6 to 8 parts of mushroom nano chitin compound, 1 to 2 parts of chain extender and 1 to 2 parts of antioxidant. According to the preparation method, mushroom nano chitin (ChNF) is utilized, surface modification is carried out through 3, 4-dihydro-2H-1, 4-benzoxazine-7-methyl formate (BZ-M), and nano diamond is anchored on the surface of ChNF in situ; and in the subsequent melt blending process, micro-crosslinking with a PET molecular chain is continued, so that the multiple barrier properties of oxygen barrier property, water vapor barrier property, ultraviolet barrier property and bacteria barrier property of the PET composite material are improved under the condition that the mechanical property and light transmittance are maintained.

Description

Technical Field

[0001] This invention relates to the field of high-barrier PET composite materials, and more specifically, to a high-barrier PET composite material, its preparation method, and its application. Background Technology

[0002] Polyethylene terephthalate (PET) is widely used in food packaging, beverage bottles, and fiber industries due to its excellent mechanical properties, transparency, and recyclability. However, traditional PET has insufficient barrier properties against oxygen and water vapor and lacks antibacterial properties, making it susceptible to microbial adhesion during room temperature storage and transportation, further shortening shelf life and posing safety hazards. This limits its use in high-barrier, long-shelf-life products. To improve barrier properties, existing technologies often use inorganic fillers such as nano-clay, graphene, or metal oxides. However, these materials have high surface inertness and weak affinity with PET ester groups, often resulting in poor interfacial compatibility with the PET matrix, leading to difficulties in dispersion and easy aggregation, further reducing mechanical properties and transparency. Therefore, how to improve barrier properties while maintaining the transparency and mechanical advantages of PET has become a pressing technical challenge for PET applications. Summary of the Invention

[0003] To overcome the defects described in the prior art, the present invention provides a high-barrier PET composite material.

[0004] Another object of the present invention is to provide a method for preparing a high-barrier PET composite material.

[0005] Another object of the present invention is to provide an application of a high-barrier PET composite material.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: A high-barrier PET composite material is prepared from polyethylene terephthalate (PET), mushroom nano-chitin composite, antioxidant, and chain extender; wherein, by mass parts, it includes the following raw materials: 80-90 parts of polyethylene terephthalate, 6-8 parts of mushroom nano-chitin composite, 1-2 parts of chain extender, and 1-2 parts of antioxidant.

[0007] Preferably, the intrinsic viscosity of the polyethylene terephthalate is 0.8~0.83 dL / g.

[0008] Preferably, the antioxidant comprises one of antioxidant 1010 and antioxidant 168.

[0009] Preferably, the chain extender comprises one of chain extender 4300 and chain extender 4368.

[0010] Furthermore, the mushroom-based nano-chitin composite is prepared by the following method: S1 Mix mushroom nano-chitin suspension with nanodiamond, stir and ultrasonically disperse; then add acetone, then add methyl 3,4-dihydro-2H-1,4-benzoxazine-7-carboxylate, adjust the pH value and stir the reaction to obtain the reaction product. S2. Filter and wash the reaction product described in step S1, and then filter again to obtain a filter cake; after drying the filter cake, obtain the mushroom nano-chitin composite. The mushroom nano-chitin suspension contains mushroom nano-chitin and water.

[0011] The mass ratio of the mushroom nano-chitin suspension to acetone is 1:(1~3).

[0012] Preferably, in step S1, the mushroom raw material for preparing the mushroom nano-chitin suspension includes one of shiitake mushrooms, oyster mushrooms, enoki mushrooms, and king oyster mushrooms.

[0013] Preferably, in step S1, the mushroom raw material for preparing the mushroom nano-chitin suspension includes shiitake mushrooms.

[0014] Preferably, in step S1, the mass percentage of mushroom nano-chitin in the mushroom nano-chitin suspension is 1% to 2%.

[0015] Preferably, in step S1, the mass ratio of the mushroom nano-chitin suspension to nanodiamonds is 200:(0.3~1).

[0016] Preferably, in step S1, the mass ratio of the mushroom nano-chitin suspension to nanodiamonds is 200:(0.5~0.7).

[0017] Preferably, in step S1, the particle size of the nanodiamond is 5~15nm.

[0018] Preferably, in step S1, the ultrasonic dispersion is performed by stirring at a speed of 500-1000 rpm.

[0019] Preferably, in step S1, the ultrasonic dispersion is performed with an ultrasonic power of 700~900W.

[0020] Preferably, in step S1, the mass ratio of the mushroom nano-chitin suspension to acetone is 1:(1~2).

[0021] Preferably, in step S1, the mass ratio of methyl 3,4-dihydro-2H-1,4-benzoxazine-7-carboxylate to the mushroom nano-chitin suspension is (1~3):200.

[0022] Preferably, in step S1, the mass ratio of methyl 3,4-dihydro-2H-1,4-benzoxazine-7-carboxylate to the mushroom nano-chitin suspension is (1~2):200.

[0023] Preferably, in step S1, the pH value is adjusted to 3-5.

[0024] Preferably, in step S1, the stirring reaction is carried out at a speed of 500-1000 rpm, a reaction temperature of 70-90°C, and a reaction time of 2-4 hours.

[0025] Preferably, in step S2, the washing includes washing with an aqueous ethanol solution of 50-80% by mass and / or washing with water.

[0026] Preferably, in step S2, the drying includes freeze drying and vacuum drying.

[0027] A method for preparing a high-barrier PET composite material includes the following steps: According to the formula ratio, weigh out polyethylene terephthalate, mushroom nano-chitin composite, antioxidant, and chain extender. Mix the weighed polyethylene terephthalate, mushroom nano-chitin composite, antioxidant, and chain extender, and then feed them into a twin-screw extruder. Melt extrusion granulation is performed at 260-290℃ to obtain a high-barrier PET composite material.

[0028] Preferably, the melt extrusion granulation temperature of the twin-screw extruder is as follows: injection port: 270~280℃, diverter block: 280~290℃, nozzle: 270~280℃, front section: 270~280℃, middle section: 265~275℃, rear section: 260~270℃.

[0029] Application of a high-barrier PET composite material in the manufacture of medicine bottles.

[0030] In this invention, mushroom nano-chitin (ChNF) possesses a high aspect ratio and excellent dispersibility, significantly extending the gas diffusion path within a PET matrix. Its surface hydroxyl groups are covalently coupled with methyl 3,4-dihydro-2H-1,4-benzoxazine-7-carboxylate, forming a synergistic interface modification with nanodiamonds, which both prevents filler aggregation and maintains high transparency. Furthermore, mushroom nano-chitin is derived from renewable resources, achieving an organic unity of mechanical reinforcement, gas barrier properties, and green sustainability.

[0031] In this invention, nanodiamond (ND) has an ultra-hard structure. On the one hand, nanodiamond forms a dense structure in the PET matrix, significantly reducing the transmittance of O2 and CO2. On the other hand, under the dispersion of fungal chitin, it crosslinks with methyl 3,4-dihydro-2H-1,4-benzoxazine-7-carboxylate to form a chemical anchor, achieving interface strengthening and uniform dispersion. While maintaining transparency, it enhances the barrier capabilities of oxygen, water vapor, ultraviolet rays, etc., thus completing the enhancement, barrier, and functionalization.

[0032] In this invention, methyl 3,4-dihydro-2H-1,4-benzoxazine-7-carboxylate (BZ-M) is covalently bonded to the hydroxyl / amino groups on the surface of ChNF, and the other end can also react with the carboxyl or hydroxyl groups at the PET end to form crosslinks; it can simultaneously fix nanodiamonds and micro-crosslink the PET matrix, thereby significantly improving barrier properties and mechanical strength.

[0033] In this invention, the acetylamino group on the surface of mushroom nano-chitine possesses a certain degree of hydrophobicity. Further modification with methyl 3,4-dihydro-2H-1,4-benzoxazine-7-carboxylate enhances its compatibility with PET, while maintaining the product's light transmittance. The acetylamino group on the surface of mushroom nano-chitine, along with the new amine group formed after modification with methyl 3,4-dihydro-2H-1,4-benzoxazine-7-carboxylate, synergistically improves the product's antibacterial properties, further enhancing its overall performance.

[0034] Compared with the prior art, the beneficial effects of the technical solution of the present invention are: This invention utilizes mushroom-derived chitin nanofibers (ChNF) and, through surface modification with methyl 3,4-dihydro-2H-1,4-benzoxazine-7-carboxylate (BZ-M), anchors nanodiamonds in situ onto the ChNF surface. In subsequent melt blending, micro-crosslinking with PET molecular chains further enhances the PET composite material's barrier properties while maintaining mechanical properties and light transmittance: tensile strength can reach up to 75 MPa, and water vapor transmission can be reduced to as low as 0.31 g / (m²). 2 (24h) Improved oxygen barrier performance, with oxygen permeability reduced to as low as 3.0 cm. 3 / (m 2 (24h, 0.1 MPa) The ultraviolet transmittance is significantly reduced to a minimum of 18%, while the visible light transmittance can reach a maximum of 86.7%, and the antibacterial performance against E. coli can reach a maximum of 97%. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the preparation process of mushroom nano-chitin suspension in an embodiment of the present invention. Detailed Implementation

[0036] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field.

[0037] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0038] The raw materials used in the embodiments and comparative examples are described below, but are not limited to these materials: PET: Polyethylene terephthalate, intrinsic viscosity: 0.8~0.83 dL / g, Maclean.

[0039] Methyl 3,4-dihydro-2H-1,4-benzoxazine-7-carboxylate: Maclean, 98%.

[0040] Nanodiamond powder, 5~15nm, ≥99%, Aladdin.

[0041] The shiitake mushrooms are produced by Fangjiapuzi (Putian) Green Food Co., Ltd.

[0042] Cellulose nanocrystal (CNC) suspension: L: ~200nm, OD: ~10nm, C909405, McLean.

[0043] Chain extender 4368: Joncryl ADR-4368-C, BASF.

[0044] Chain extender 4300: Joncryl ADR-4300, BASF.

[0045] Antioxidant 1010: Irganox 1010, BASF.

[0046] Antioxidant 168: Irgafos 168, BASF.

[0047] The mushroom nano-chitin (ChNF) was prepared by the inventor using the following steps: 10g of shiitake mushrooms (dry weight) were cut into small pieces no larger than 0.5 cm × 0.5 cm and soaked in 200 mL of 80℃ hot water for 2 hours; then filtered, the residue was collected, and 200 mL of 1 mol / L NaOH solution was added, and the mixture was reacted at 85℃ for 6 hours; after the reaction, the mixture was filtered, and the insoluble matter was collected; the obtained insoluble matter was placed in a 1% (w / w) hydrogen peroxide aqueous solution and reacted at 85℃ for 3 hours; then filtered, and washed with deionized water until the pH of the washing solution was 7.0 ± 0.2, and the precipitate was collected; the precipitate was homogenized under high pressure (cycled 5 times) and concentrated to a (w / w) concentration of 1% to obtain a mushroom nano-chitin suspension. Preferably, the concentration includes rotary evaporation concentration.

[0048] Example 1 (1) Take 200 g of mushroom nano-chitin suspension with a mass percentage concentration of 1%, add 0.3 g of nano-diamond, stir at 800 rpm for 30 minutes, and then sonicate at 800 W for 30 minutes to make the nano-diamond uniformly dispersed; then add 200 g of acetone (the mass ratio of mushroom nano-chitin suspension to acetone is 1:1), and then add 1 g of methyl 3,4-dihydro-2H-1,4-benzoxazine-7-carboxylate. Adjust the pH value to 4.0 with 1 mol / L hydrochloric acid, stir at 600 rpm and react at 80℃ for 3 h to obtain the reaction product.

[0049] (2) The reaction product described in step (1) is filtered, washed with 70% ethanol aqueous solution and deionized water until the pH value is 6.8~7.2, and then filtered to obtain filter cake; after freeze drying, mushroom nano-chitin complex is obtained.

[0050] (3) Preparation method of high barrier PET composite material: 90 parts of polyethylene terephthalate, 8 parts of mushroom nano-chitin composite, 2 parts of antioxidant (antioxidant 1010), and 2 parts of chain extender (chain extender 4300) are weighed according to the proportion. After mixing the above-weighed polyethylene terephthalate, mushroom nano-chitin composite, antioxidant, and chain extender, they are fed into a twin-screw extruder. The temperature of each section of the extruder is adjusted. After the material has been melt-blended, it is extruded through the extruder head to form a high barrier PET composite material. The temperature of the twin-screw extruder is as follows: injection port: 275°C, splitter block: 285°C, nozzle: 275°C, front part: 275°C, middle part: 270°C, rear part: 260°C.

[0051] Example 2 Example 2 is similar to Example 1, except that 0.5 g of nanodiamond is added in step (1).

[0052] Example 3 Example 3 is similar to Example 1, except that in step (1), 0.7 g of nano diamond, 2 g of methyl 3,4-dihydro-2H-1,4-benzoxazine-7-carboxylate, and 400 g of acetone were added (the mass ratio of mushroom nano chitin suspension to acetone was 1:2).

[0053] Example 4

[0054] Example 4 is similar to Example 1, except that 1 g of nanodiamond is added in step (1).

[0055] Example 5

[0056] The mushroom nano-chitin suspension was concentrated to a mass percentage of 2% for the mushroom nano-chitin.

[0057] Example 5 is similar to Example 1, except that in step (1), 200 g of 2% mushroom nano-chitin suspension is added; 3 g of methyl 3,4-dihydro-2H-1,4-benzoxazine-7-carboxylate is added; and 600 g of acetone is added (the mass ratio of mushroom nano-chitin suspension to acetone is 1:3). In step (3), the preparation method of high-barrier PET composite material is as follows: 80 parts of polyethylene terephthalate, 6 parts of mushroom nano-chitin composite, 1 part of antioxidant (antioxidant 168), and 1 part of chain extender (chain extender 4368) are weighed.

[0058] Example 6

[0059] This embodiment provides a packaging bottle made of high-barrier PET composite material; the mushroom nano-chitin composite is the same as in Example 1. The packaging bottle is prepared as follows: 90 parts of polyethylene terephthalate, 6 parts of mushroom nano-chitin composite, 1 part of antioxidant (antioxidant 1010), and 1 part of chain extender (chain extender 4300) are weighed. The weighed polyethylene terephthalate, mushroom nano-chitin composite, antioxidant, and chain extender are mixed and fed into a twin-screw extruder. The temperature of each section of the extruder is adjusted. The melt-blended material is extruded through the extruder head and then injection molded into a preform to obtain a PET packaging bottle. The twin-screw extruder has the following temperatures: injection port: 275°C, manifold: 285°C, nozzle: 275°C (front section 275°C, middle section 270°C, rear section 260°C). During injection molding, the nozzle temperature is 270°C, the first stage temperature is 265°C, and the second stage temperature is 275°C.

[0060] Comparative Example 1 Comparative Example 1 is similar to Example 1, except that in step (1), no mushroom nano-chitin is added, and a cellulose nanocrystal suspension with a mass percentage of 1% is used instead of the mushroom nano-chitin suspension.

[0061] Comparative Example 2 Comparative Example 2 is similar to Example 1, except that nanodiamonds are not added in step (1).

[0062] Comparative Example 3 Comparative Example 3 is similar to Example 1, except that methyl 3,4-dihydro-2H-1,4-benzoxazine-7-carboxylate is not added in step (1).

[0063] Comparative Example 4 Comparative Example 4 is similar to Example 1, except that the amount of acetone added in step (1) is 100 g.

[0064] Comparative Example 5 Comparative Example 5 is similar to Example 1, except that in step (3), the preparation method of the high-barrier PET composite material is as follows: weigh 75 parts of polyethylene terephthalate, 15 parts of mushroom nano-chitin composite, 1 part of antioxidant (antioxidant 1010), and 1 part of chain extender (chain extender 4300).

[0065] Comparative Example 6 Comparative Example 6 is a commercially available brand of PET packaging material.

[0066] Analysis and testing The obtained PET material was pressed into plastic sheets of standard size; tensile properties were tested according to GB / T 1040.2-2006; antibacterial properties were evaluated against Escherichia coli (ATCC 25922) according to ISO 22196:2011; water vapor transmission was tested according to GB / T 1037-2021, with a temperature of 25℃ and a relative humidity of 50% during the test; oxygen transmission was tested according to GB / T 1038-2022, with a temperature of 25℃ and a relative humidity of 50% during the test; light transmittance was measured according to GB / T2410-2008; ultraviolet transmittance and light transmittance were measured using a UV-Vis spectrophotometer with an integrating sphere (UV-2600i, Shimadzu Corporation, Japan). Results are shown in Table 1. Table 1 Test results of PET composite materials

[0067] Results analysis: The results of Examples 1-5 show that, compared with commercially available PET packaging materials, the overall performance of the product obtained by the preferred embodiment of the present invention is significantly improved, with a maximum tensile strength of 75 MPa and a minimum water vapor transmission rate of 0.31 g / (m²). 2 (24h) Improved oxygen barrier performance, with oxygen permeability reduced to as low as 3.0 cm. 3 / (m 2 (24h, 0.1 MPa) The ultraviolet transmittance is significantly reduced to a minimum of 18%, while the visible light transmittance can reach a maximum of 86.7%, and the antibacterial performance against E. coli can reach a maximum of 97%.

[0068] As can be seen from Example 1 and Comparative Example 1, when cellulose nanocrystals (CNC) are used to replace mushroom nano-chitin (ChNF), the water vapor permeability is 0.54 g / (m²) due to the lack of aspect ratio and surface functional groups of ChNF. 2 (24h), oxygen permeability was 5.3 cm. 3 / (m 2 (24h·0.1MPa), light transmittance decreases, and overall quality deteriorates significantly.

[0069] Comparative Example 2, without the addition of nanodiamonds, resulted in a decrease in the product's mechanical properties and a significant decrease in its gas barrier properties.

[0070] In Comparative Example 3, without the addition of BZ-M for surface modification, the compatibility of the mushroom nano-chitin composite deteriorated, leading to a decline in the overall performance of the product.

[0071] As can be seen from the results of Comparative Example 4, the mass ratio of mushroom nano-chitin suspension to acetone in the preparation process of mushroom nano-chitin complex is not within the preferred range of the present invention, resulting in the overall performance of the product being inferior to that of Examples 1-5.

[0072] In Comparative Example 5, the amount of polyethylene terephthalate (PET) and mushroom nano-chitin composite used in the preparation method of the PET composite material is not within the preferred range of the present invention, resulting in a decrease in the overall performance of the product.

[0073] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A high-barrier PET composite material, characterized in that, By weight, it includes the following raw materials: 80-90 parts polyethylene terephthalate, 6-8 parts mushroom nano-chitin complex, 1-2 parts chain extender, and 1-2 parts antioxidant.

2. The high-barrier PET composite material according to claim 1, characterized in that, The preparation method of the mushroom nano-chitin complex includes the following steps: S1 Mix mushroom nano-chitin suspension with nanodiamond, stir and ultrasonically disperse; then add acetone, then add methyl 3,4-dihydro-2H-1,4-benzoxazine-7-carboxylate, adjust the pH value and stir the reaction to obtain the reaction product. S2. Filter and wash the reaction product described in step S1, and then filter again to obtain a filter cake; after drying the filter cake, obtain the mushroom nano-chitin composite. The mushroom nano-chitin suspension contains mushroom nano-chitin and water; The mass ratio of the mushroom nano-chitin suspension to acetone is 1:(1~3).

3. The high-barrier PET composite material according to claim 1, characterized in that, The intrinsic viscosity of the polyethylene terephthalate is 0.8~0.83 dL / g.

4. The high-barrier PET composite material according to claim 1, characterized in that, The chain extender includes one of chain extender 4300 and chain extender 4368.

5. The high-barrier PET composite material according to claim 2, characterized in that, The mass ratio of the mushroom nano-chitin suspension to nanodiamonds in step S1 is 200:(0.3~1).

6. The high-barrier PET composite material according to claim 2, characterized in that, The mass ratio of methyl 3,4-dihydro-2H-1,4-benzoxazine-7-carboxylate to the mushroom nano-chitin suspension in step S1 is (1~3):

200.

7. The high-barrier PET composite material according to claim 2, characterized in that, The mass ratio of the mushroom nano-chitin suspension to acetone in step S1 is 1:(1~2).

8. The high-barrier PET composite material according to claim 2, characterized in that, The mass percentage of mushroom nano-chitin in the mushroom nano-chitin suspension described in step S1 is 1%~2%.

9. The method for preparing the high-barrier PET composite material according to any one of claims 1 to 8, characterized in that, Includes the following steps: According to the formula ratio, weigh out polyethylene terephthalate, mushroom nano-chitin composite, antioxidant, and chain extender; mix the above-weighed polyethylene terephthalate, mushroom nano-chitin composite, antioxidant, and chain extender and put them into a twin-screw extruder, and melt extrude and granulate at 260-290℃ to obtain high-barrier PET composite material.

10. The application of the high-barrier PET composite material according to any one of claims 1 to 8, characterized in that, Used to manufacture packaging bottles.

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