High-barrier pet composite material and preparation method and application thereof

Abstract

The application relates to the field of high-barrier PET composite materials, and relates to a high-barrier PET composite material and a preparation method and application thereof.The high-barrier PET composite material comprises the following raw materials in parts by mass: 80-90 parts of polyethylene terephthalate, 6-8 parts of mushroom nanochitin compound, 1-2 parts of a chain extender, and 1-2 parts of an antioxidant.The application utilizes mushroom nanochitin (ChNF) and in-situ anchors nanodiamond on the surface of the ChNF through surface modification of 3,4-dihydro-2H-1,4-benzoxazine-7-methyl formate (BZ-M); in subsequent melt blending, the nanodiamond continues to be micro-crosslinked with PET molecular chains, so that the multiple barrier properties of the PET composite material, including oxygen barrier property, water vapor barrier property, ultraviolet barrier property and bacterial barrier property, are greatly improved while the mechanical property and light transmittance are maintained.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high-barrier PET composite materials, and more particularly to a high-barrier PET composite material, a preparation method thereof and an application thereof. BACKGROUND

[0002] Polyethylene terephthalate (PET) has been widely used in food packaging, beverage bottles and fiber fields due to its excellent mechanical properties, transparency and recyclability. However, the conventional PET has insufficient barrier properties to oxygen and water vapor, and lacks antibacterial function itself, and is easily attached by microorganisms during storage and transportation at room temperature, which further shortens the shelf life and brings safety hazards. Its use in high-barrier and long-shelf-life products is limited. In order to improve the barrier property, the existing technology often uses inorganic fillers such as nano-clay, graphene or metal oxide, but these materials have high surface inertness and weak affinity with PET ester groups, and often have poor interfacial compatibility with the PET matrix, which leads to difficulties in dispersion and easy agglomeration, and further leads to a decrease in mechanical properties and transparency. Therefore, how to improve the barrier property while maintaining the transparency and mechanical advantages of PET has become a technical problem to be solved in the application of PET. SUMMARY

[0003] The present application provides a high-barrier PET composite material to overcome the above-mentioned defects of the prior art.

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

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

[0006] To solve the above technical problems, the technical solution of the present application is as follows:

[0007] A high-barrier PET composite material is prepared from polyethylene terephthalate (PET), mushroom nanochitin composite, antioxidant and chain extender; wherein, the high-barrier PET composite material comprises the following raw materials in parts by mass: 80-90 parts of polyethylene terephthalate, 6-8 parts of mushroom nanochitin composite, 1-2 parts of chain extender and 1-2 parts of antioxidant.

[0008] Preferably, the intrinsic viscosity of the polyethylene terephthalate is 0.8-0.83 dL / g.

[0009] Preferably, the antioxidant comprises one of antioxidant 1010 and antioxidant 168.

[0010] Preferably, the chain extender comprises one of chain extender 4300 and chain extender 4368.

[0011] Further, the mushroom nanochitin complex is prepared by the following method:

[0012] S1: mixing the mushroom nanochitin suspension with nanodiamonds, stirring and ultrasonic dispersion; then adding acetone, adding 3,4-dihydro-2H-1,4-benzoxazine-7-methyl formate, adjusting the pH value, and stirring and reacting to obtain a reaction product;

[0013] S2: filtering the reaction product of step S1, washing, and then filtering to obtain a filter cake; drying the filter cake to obtain the mushroom nanochitin complex;

[0014] The mushroom nanochitin suspension comprises mushroom nanochitin and water.

[0015] The mass ratio of the mushroom nanochitin suspension to acetone is 1: (1-3).

[0016] Preferably, in step S1, the mushroom raw material for preparing the mushroom nanochitin suspension comprises one of shiitake mushrooms, shimeji mushrooms, golden needle mushrooms, and pleurotus eryngii.

[0017] Preferably, in step S1, the mushroom raw material for preparing the mushroom nanochitin suspension comprises shiitake mushrooms.

[0018] Preferably, in step S1, the mass percentage of mushroom nanochitin in the mushroom nanochitin suspension is 1%-2%.

[0019] Preferably, in step S1, the mass ratio of the mushroom nanochitin suspension to nanodiamonds is 200: (0.3-1).

[0020] Preferably, in step S1, the mass ratio of the mushroom nanochitin suspension to nanodiamonds is 200: (0.5-0.7).

[0021] Preferably, in step S1, the particle size of the nanodiamonds is 5-15 nm.

[0022] Preferably, in step S1, the stirring and ultrasonic dispersion is performed at a stirring speed of 500-1000 revolutions per minute.

[0023] Preferably, in step S1, the stirring and ultrasonic dispersion is performed at an ultrasonic power of 700-900 W.

[0024] Preferably, in step S1, the mass ratio of the mushroom nanochitin suspension to acetone is 1: (1-2).

[0025] Preferably, in step S1, the mass ratio of the 3,4-dihydro-2H-1,4-benzoxazine-7-methyl formate to the mushroom nanochitin suspension is (1-3):200.

[0026] Preferably, in step S1, the mass ratio of the 3,4-dihydro-2H-1,4-benzoxazine-7-methyl formate to the mushroom nanochitin suspension is (1-2):200.

[0027] Preferably, in step S1, the pH value is adjusted to 3-5.

[0028] Preferably, in step S1, the stirring reaction is carried out at a rotation speed of 500-1000 rpm, a reaction temperature of 70-90℃, and a reaction time of 2-4h.

[0029] Preferably, in step S2, the washing includes washing with an ethanol aqueous solution with a mass percentage of 50-80% and / or water washing.

[0030] Preferably, in step S2, the drying includes freeze drying and vacuum drying.

[0031] A preparation method of a high-barrier PET composite material, comprising the following steps:

[0032] The polyethylene terephthalate, the mushroom nanochitin composite, the antioxidant, and the chain extender are weighed according to the formula ratio, mixed uniformly, and then fed into a double-screw extruder to be melt-extruded and granulated at 260-290℃ to obtain the high-barrier PET composite material.

[0033] Preferably, the melt-extrusion granulation temperature of the double-screw extruder is 270-280℃ at the injection port, 280-290℃ at the flow divider, 270-280℃ at the nozzle, 270-280℃ at the front part, 265-275℃ at the middle part, and 260-270℃ at the rear part.

[0034] The application of the high-barrier PET composite material in the preparation of a medicine bottle.

[0035] In the present application, the mushroom nanochitin (ChNF) has a high aspect ratio and excellent dispersibility, can significantly prolong the gas diffusion path in the PET matrix, and the surface hydroxyl group is covalently coupled with 3,4-dihydro-2H-1,4-benzoxazine-7-methyl formate to form an interface modification in cooperation with nanodiamonds, which not only prevents filler agglomeration but also maintains high transparency. At the same time, the mushroom nanochitin is derived from renewable resources, realizing the organic unity of mechanical enhancement, gas barrier, and green sustainability.

[0036] In the present application, the nanodiamond (ND) has a superhard structure, which forms a dense structure in the PET matrix, significantly reducing the O2 and CO2 permeability, and is crosslinked with 3,4-dihydro-2H-1,4-benzoxazine-7-methyl formate under the dispersion of mushroom chitin to form chemical anchoring, realizing interface strengthening and uniform dispersion, improving the barrier ability of oxygen, water vapor, ultraviolet light and other aspects under the premise of maintaining transparency, and completing the enhancement, barrier and functionalization.

[0037] In the present application, 3,4-dihydro-2H-1,4-benzoxazine-7-methyl formate (BZ-M) is covalently bonded with the surface hydroxyl / amino of ChNF, and the other end can also react with the terminal carboxyl or hydroxyl of PET to form crosslinking; nanodiamonds can be fixed and micro-crosslinked PET matrix at the same time, thereby significantly improving the barrier property and mechanical strength.

[0038] In the present application, the acetylamino on the surface of mushroom nanochitin has certain hydrophobicity, and the compatibility with PET is improved by further modification of 3,4-dihydro-2H-1,4-benzoxazine-7-methyl formate, so that the light transmittance of the product is maintained. Under the action of the acetylamino on the surface of mushroom nanochitin and the new amine group formed after modification of 3,4-dihydro-2H-1,4-benzoxazine-7-methyl formate, the antibacterial performance of the product is synergistically improved, and the comprehensive performance of the product is further improved.

[0039] Compared with the prior art, the beneficial effects of the technical scheme of the present application are:

[0040] The present application utilizes mushroom nanochitin (ChNF) and modifies the surface of 3,4-dihydro-2H-1,4-benzoxazine-7-methyl formate (BZ-M) to anchor nanodiamonds in situ on the surface of ChNF; in the subsequent melt blending, the PET molecular chain is continuously micro-crosslinked, so that the PET composite material realizes the improvement of various barrier properties while maintaining the mechanical properties and light transmittance: the tensile strength can be as high as 75 Mpa, the water vapor transmission rate can be as low as 0.31 g / (m 2 ·24h),the oxygen barrier performance is improved, the oxygen transmission rate can be as low as 3.0 cm 3 / (m 2 ·24h·0.1Mpa),the ultraviolet transmittance is significantly reduced and can be as low as 18%, the visible light transmittance can be as high as 86.7%, and the antibacterial performance against E. coli can be as high as 97%. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 The present application is a schematic diagram for the preparation process of mushroom nanochitin suspension in the embodiments. DETAILED DESCRIPTION

[0042] The present application will be further described with reference to the drawings and specific examples, but the examples do not limit the present application in any form. Unless otherwise specified, the reagents, methods and equipment used in the present application are conventional reagents, methods and equipment in the art.

[0043] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0044] The raw materials used in the examples and comparative examples are described as follows, but are not limited to these materials:

[0045] PET: polyethylene terephthalate, intrinsic viscosity: 0.8~0.83 dL / g, Maclin.

[0046] 3,4-Dihydro-2H-1,4-benzoxazine-7-carboxylic acid methyl ester: Maclin, 98%.

[0047] Nano diamond powder, 5~15 nm, ≥99%, Aladdin.

[0048] Shiitake mushrooms are from Fangjiapuzi (Putian) Green Food Co., Ltd.

[0049] Cellulose nanocrystal (CNC) suspension: L: ~200 nm, OD: ~10 nm, C909405, Maclin.

[0050] Chain extender 4368: Joncryl ADR-4368-C, BASF.

[0051] Chain extender 4300: Joncryl ADR-4300, BASF.

[0052] Antioxidant 1010: Irganox 1010, BASF.

[0053] Antioxidant 168: Irgafos 168, BASF.

[0054] Mushroom nanochitin (ChNF) is self-made by the inventors, and the specific steps are as follows: 10 g of shiitake mushrooms (dry weight) are cut into small pieces not greater than 0.5 cm x 0.5 cm, and then soaked in 200 mL of 80°C hot water for 2 h; then filtered, collected the residue, added 200 mL of 1 mol / L NaOH solution, and reacted at 85°C for 6 h; after the reaction, the insoluble material is collected by filtration; the obtained insoluble material is placed in a 1% hydrogen peroxide aqueous solution, and reacted at 85°C for 3 h; then filtered, washed with deionized water until the pH of the washing liquid is 7.0±0.2, and the precipitate is collected; the precipitate is treated by high-pressure homogenization (5 cycles), concentrated to a mass percentage concentration of 1%, and a mushroom nanochitin suspension is obtained. Preferably, the concentration includes rotary evaporation concentration.

[0055] Example 1

[0056] (1) 200 g of a mushroom nanochitin suspension with a mass percentage concentration of 1% is taken, 0.3 g of nanodiamond is added, and stirred at 800 rpm for 30 min, and then ultrasonic is performed at 800 w for 30 min to uniformly disperse the nanodiamond; then 200 g of acetone (mass ratio of mushroom nanochitin suspension to acetone is 1:1) is added, and then 1 g of 3,4-dihydro-2H-1,4-benzoxazine-7-carboxylic acid methyl ester is added, and the pH value is adjusted to 4.0 with 1 mol / L hydrochloric acid, and stirred at 600 rpm for 3 h at 80°C to obtain a reaction product.

[0057] (2) The reaction product of step (1) is filtered, washed with a 70% ethanol aqueous solution and deionized water until the pH value is 6.8-7.2, and then filtered to obtain a filter cake; after freeze-drying, a mushroom nanochitin composite is obtained.

[0058] (3) The preparation method of the high-barrier PET composite material is as follows: 90 parts of polyethylene terephthalate, 8 parts of mushroom nanochitin composite, 2 parts of antioxidant (antioxidant 1010), and 2 parts of chain extender (chain extender 4300) are weighed according to the proportion; the above-mentioned polyethylene terephthalate, mushroom nanochitin composite, antioxidant, and chain extender are mixed uniformly and then put into a double-screw extruder; the temperature of each section of the extruder is adjusted; the material after melt blending is extruded through the extruder head to form a high-barrier PET composite material; the injection port of the double-screw extruder is at 275°C, the flow block is at 285°C, the nozzle is at 275°C, the front part is at 275°C, the middle part is at 270°C, and the rear part is at 260°C.

[0059] Example 2

[0060] Example 2 is similar to Example 1, except that 0.5 g of nanodiamond is added in step (1).

[0061] Example 3

[0062] Example 3 is similar to Example 1, except that in step (1), 0.7 g of nanodiamonds is added, 2 g of methyl 3,4-dihydro-2H-1,4-benzoxazine-7-carboxylate is added, and 400 g of acetone is added (the mass ratio of the mushroom nanochitin suspension to acetone is 1:2).

[0063] Example 4

[0064] Example 4 is similar to Example 1, except that in step (1), 1 g of nanodiamonds is added.

[0065] Example 5

[0066] The mushroom nanochitin suspension is concentrated to a mass percentage of 2% of the mushroom nanochitin in the suspension.

[0067] Example 5 is similar to Example 1, except that in step (1), 200 g of 2% mushroom nanochitin 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 the mushroom nanochitin suspension to acetone is 1:3). Step (3) is a method for preparing a high-barrier PET composite material, 80 parts of polyethylene terephthalate, 6 parts of mushroom nanochitin composite, 1 part of antioxidant (antioxidant 168), and 1 part of chain extender (chain extender 4368) are weighed.

[0068] Example 6

[0069] This example provides a packaging bottle prepared from a high-barrier PET composite material; the mushroom nanochitin composite is the same as in Example 1. The packaging bottle is prepared as follows: 90 parts of polyethylene terephthalate, 6 parts of mushroom nanochitin composite, 1 part of antioxidant (antioxidant 1010), and 1 part of chain extender (chain extender 4300) are weighed. The above-weighed polyethylene terephthalate, mushroom nanochitin composite, antioxidant, and chain extender are mixed uniformly and then fed into a twin-screw extruder, the temperature of each section of the extruder is adjusted, and the material after melt blending is extruded through the extruder head, and then injection molded into a bottle embryo to prepare a PET packaging bottle. The injection port in the twin-screw extruder is at 275°C, the flow block is at 285°C, the nozzle is at 275°C, the front part is at 275°C, the middle part is at 270°C, and the rear part is at 260°C. The nozzle temperature during injection molding is 270°C, the first-stage temperature is 265°C, and the second-stage temperature is 275°C.

[0070] Comparative Example 1

[0071] This comparative example 1 is similar to Example 1, except that in step (1), no mushroom nanochitin is added, and instead, a cellulose nanocrystal suspension with a mass percentage of 1% is directly used instead of the mushroom nanochitin suspension.

[0072] Comparative Example 2

[0073] Comparative Example 2 is similar to Example 1, except that no nano-diamond is added in step (1).

[0074] Comparative Example 3

[0075] Comparative Example 3 is similar to Example 1, except that no 3,4-dihydro-2H-1,4- benzoxazine-7-carboxylic acid methyl ester is added in step (1).

[0076] Comparative Example 4

[0077] Comparative Example 4 is similar to Example 1, except that the amount of acetone added in step (1) is 100 g.

[0078] Comparative Example 5

[0079] Comparative Example 5 is similar to Example 1, except that the preparation method of high barrier PET composite material in step (3) is as follows: 75 parts of polyethylene terephthalate, 15 parts of mushroom nano-chitin compound, 1 part of antioxidant (antioxidant 1010), and 1 part of chain extender (chain extender 4300) are weighed.

[0080] Comparative Example 6

[0081] Comparative Example 6 is a commercially available brand of PET packaging material.

[0082] Analysis and detection

[0083] The obtained PET material is pressed into a standard size plastic sheet; the tensile property test refers to GB / T 1040.2-2006; the antibacterial property is evaluated according to the method of ISO 22196:2011 for antibacterial property against Escherichia coli (ATCC 25922); the water vapor transmission rate is detected according to GB / T 1037-2021, and during the test process, the temperature is 25°C and the relative humidity is 50%; the oxygen transmission rate is detected according to GB / T 1038-2022, and during the test process, the temperature is 25°C and the relative humidity is 50%; the light transmittance refers to the method of GB / T 2410-2008; the ultraviolet transmittance and light transmittance are determined by a UV-visible spectrophotometer with an integrating sphere (UV-2600i, Shimadzu Corporation, Japan). The result data are shown in Table 1:

[0084] Table 1: Detection results of PET composite material

[0085]

[0086] Result analysis:

[0087] The results of examples 1-5 show that, compared with the commercially available PET packaging material, the comprehensive performance of the product obtained by the preferred scheme of the application is significantly improved, the tensile strength can reach up to 75 Mpa, the water vapor transmission rate can be reduced to 0.31 g / (m 2 ·24h), the oxygen barrier performance is improved, the oxygen transmission rate can be reduced to 3.0 cm 3 / (m 2 ·24h·0.1Mpa), the ultraviolet transmission rate is significantly reduced and can be reduced to 18%, the visible light transmission rate can reach up to 86.7%, and the antibacterial performance can reach up to 97% against E. coli.

[0088] As can be seen from example 1 and comparative example 1, after replacing the chitin nanofiber (ChNF) with cellulose nanocrystals (CNC), due to the lack of aspect ratio and surface functional groups of ChNF, the water vapor transmission rate is 0.54 g / (m 2 ·24h), the oxygen transmission rate is 5.3 cm 3 / (m 2 ·24h·0.1MPa), the light transmittance decreases, and the overall quality deteriorates.

[0089] Comparative example 2 does not add nanodiamond, resulting in a decrease in the mechanical properties of the product and a significant decrease in the gas barrier performance.

[0090] Comparative example 3 does not add BZ-M for surface modification, and the compatibility of the chitin nanofiber compound is poor, resulting in a decrease in the overall comprehensive performance of the product.

[0091] As can be seen from the results of comparative example 4, during the preparation of the chitin nanofiber compound, the mass ratio of the chitin nanofiber suspension to acetone is not within the preferred range of the application, resulting in an overall comprehensive performance of the product that is not as good as that of examples 1-5.

[0092] In comparative example 5, the addition amount of polyethylene terephthalate (PET) and chitin nanofiber compound used in the preparation method of the PET composite material is not within the preferred range of the application, resulting in a decrease in the overall comprehensive performance of the product.

[0093] Obviously, the above examples of the application are only examples for clearly illustrating the application, and are not intended to limit the embodiments of the application. Based on the above description, those skilled in the art can make other different forms of changes or modifications. Here, it is not necessary and impossible to exhaust all the embodiments. Any modification, equivalent replacement and improvement made within the spirit and principles of the application shall be included in the protection scope of the claims of the application.

Claims

1. A high-barrier PET composite material, characterized in that, By weight, it includes the following raw materials: 80-90 parts of polyethylene terephthalate, 6-8 parts of mushroom nano-chitin complex, 1-2 parts of chain extender, and 1-2 parts of antioxidant. 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 in step S1 is 1:(1~2); the mass ratio of the mushroom nano-chitin suspension to nanodiamond in step S1 is 200:(0.3~1); 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; the mass percentage of mushroom nano-chitin in the mushroom nano-chitin suspension in step S1 is 1%~2%.

2. 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.

3. 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.

4. The method for preparing the high-barrier PET composite material according to any one of claims 1 to 3, 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.

5. The application of the high-barrier PET composite material according to any one of claims 1 to 3, characterized in that, Used to manufacture packaging bottles.

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