Polyethylene food plastic material and preparation method thereof

Abstract

The invention relates to the field of packaging materials, in particular to a polyethylene food plastic material and a preparation method thereof. Specifically, the composition comprises the following components in percentage by weight: 1%-5% of a carvacrol beta-cyclodextrin compound, 1%-5% of a cinnamyl aldehyde montmorillonite compound, 0.3% of an antioxidant and the balance of low-density polyethylene. The carvacrol beta-cyclodextrin compound and the cinnamyl aldehyde montmorillonite compound are compounded for use, so that the polyethylene food plastic has good antibacterial performance, and the antioxidant has good anti-migration performance.

Description

Technical Field

[0001] The present invention relates to the field of packaging materials, in particular to a polyethylene food plastic material and a preparation method thereof. Background Art

[0002] Polyethylene is a widely used polymer material in the chemical industry. It is produced through the polymerization of ethylene monomers. Its odorless, tasteless, and non-toxic properties make it suitable for everyday use in items such as plastic bags, plastic wrap, and food packaging, bringing great convenience to people's lives.

[0003] As society develops, people's concern for health and the environment is increasing. Polyethylene, used in plastic wrap and food bags, needs to possess excellent antimicrobial properties to enhance food protection. However, the widespread use of disposable plastic wrap and food bags has led to a sharp increase in plastic waste, contributing to the problem of "white pollution." Plastic waste is difficult to degrade in the natural environment, and its degradation time varies depending on the environment, often requiring decades or even centuries to fully decompose. Therefore, modifying polyethylene film to improve its degradation and antimicrobial properties is of great research significance.

[0004] Among modification methods, adding various nanomaterials is a common approach. However, when nanoplastic composite packaging materials come into direct contact with food, nanocomponents and various additives can migrate into the food through absorption, dissolution, and diffusion, and then enter the human body along with the food, posing a threat to human health. Consequently, numerous researchers, both domestically and internationally, have conducted extensive research on the content and detection methods of various additives and nanocomponents in packaging materials, as well as factors influencing migration, such as time and temperature. However, relatively little research has examined the interactions between nanocomponents and various plastic additives. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a polyethylene food plastic material and a preparation method thereof.

[0006] The present invention is achieved through the following technical solutions: A polyethylene food plastic material comprises the following components by weight: 1% to 5% of a carvacrol beta-cyclodextrin complex, 1% to 5% of a cinnamaldehyde montmorillonite complex, 0.3% of an antioxidant, and the balance being low-density polyethylene.

[0007] Furthermore, the invention comprises the following components by weight percentage: 2% carvacrol β-cyclodextrin complex, 3% cinnamaldehyde montmorillonite complex, 0.3% antioxidant, and the balance low-density polyethylene.

[0008] Furthermore, the antioxidant is selected from Irganox 1706.

[0009] Furthermore, the preparation method of the carvacrol β-cyclodextrin complex is: 5 g of β-cyclodextrin and 50 mL of a 2:1 water / ethanol mixed solution were placed in a reactor and stirred at 55°C for 10 minutes to obtain a β-cyclodextrin solution. Subsequently, a 10% (v / v) carvacrol solution was prepared with ethanol. The carvacrol solution was added dropwise to the β-cyclodextrin solution and stirred at 55°C for 30 minutes. The solution was stirred for 4 hours until the temperature dropped to 25°C. The precipitate was recovered by vacuum filtration and dried at room temperature for 24 hours to obtain a carvacrol-β-cyclodextrin complex.

[0010] Furthermore, the mass ratio of the β-cyclodextrin to carvacrol is 80:20.

[0011] Furthermore, the preparation method of the cinnamaldehyde montmorillonite complex is as follows: Dissolve 3 g of methylcellulose, 0.9 g of polyethylene glycol, and 1.5 g of cinnamaldehyde in a mixture of 33 mL of water and 66 mL of ethanol and stir for 0.5 h to obtain solution A. Disperse montmorillonite in 25 mL of water and stir for 0.5 h to obtain solution B; Solution B was slowly added to solution A, stirred at room temperature for 4 h, and then dried at 60° C. for 24 h to obtain a cinnamaldehyde-montmorillonite complex.

[0012] Furthermore, the mass ratio of the montmorillonite to cinnamaldehyde is 1.5:0.2.

[0013] The present invention also provides a method for preparing a polyethylene food plastic material, comprising the following steps: uniformly blending the materials, drying them at 60° C. for 30 minutes, and granulating them through a twin-screw extruder to obtain the polyethylene food plastic material.

[0014] Furthermore, the twin-screw extruder has a total of 7 zones, the temperatures of the 7 zones are 160°C, 165°C, 175°C, 170°C, 170°C, 165°C and 165°C respectively, and the extruder speed is 45r / min.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects: the present invention not only makes the polyethylene food plastic have good antibacterial properties, but also has good anti-migration properties against antioxidants through the compound use of the carvacrol β-cyclodextrin complex and the cinnamaldehyde montmorillonite complex. DETAILED DESCRIPTION

[0016] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples. The illustrative embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0017] The preparation method of the carvacrol β-cyclodextrin complex of the present invention is as follows: 5 g of β-cyclodextrin and 50 mL of a 2:1 water / ethanol mixture were placed in a reactor and stirred at 55°C for 10 min to obtain a β-cyclodextrin solution. Subsequently, a 10% (v / v) carvacrol solution was prepared in ethanol. The carvacrol solution was added dropwise to the β-cyclodextrin solution at a mass ratio of β-cyclodextrin to carvacrol of 80:20 (w / w). The mixture was stirred at 55°C for 30 min and the solution was stirred for 4 h until the temperature dropped to 25°C. The precipitate was recovered by vacuum filtration and dried at room temperature for 24 h to obtain a carvacrol-β-cyclodextrin complex.

[0018] The preparation method of the cinnamaldehyde montmorillonite complex of the present invention: Dissolve 3 g of methylcellulose, 0.9 g of polyethylene glycol, and 1.5 g of cinnamaldehyde in a mixture of 33 mL of water and 66 mL of ethanol and stir for 0.5 h to obtain solution A. Disperse 0.2 g of montmorillonite in 25 mL of water and stir for 0.5 h to obtain solution B; Solution B was slowly added to solution A, stirred at room temperature for 4 h, and then dried at 60° C. for 24 h to obtain a cinnamaldehyde-montmorillonite complex.

[0019] In the present invention, methylcellulose was purchased from Sigma, product number M0262; polyethylene glycol was purchased from Sigma, product number 202398; and montmorillonite was purchased from Sigma, product number 281522. Example 1

[0020] A polyethylene food plastic material comprises the following components by weight: 3% carvacrol beta-cyclodextrin complex, 2% cinnamaldehyde montmorillonite complex, 0.3% antioxidant Irganox 1706, and the balance low-density polyethylene.

[0021] The preparation method is as follows: the materials are blended evenly, then dried at 60°C for 30 minutes, and granulated through a twin-screw extruder to obtain a polyethylene food plastic material; the twin-screw extruder has a total of 7 zones, and the temperatures of the 7 zones are 160°C, 165°C, 175°C, 170°C, 170°C, 165°C and 165°C respectively, and the extruder speed is 45r / min. Example 2

[0022] A polyethylene food plastic material comprises the following components by weight: 2% carvacrol beta-cyclodextrin complex, 3% cinnamaldehyde montmorillonite complex, 0.3% antioxidant Irganox 1706, and the balance low-density polyethylene.

[0023] The preparation method is as follows: the materials are blended evenly, then dried at 60°C for 30 minutes, and granulated through a twin-screw extruder to obtain a polyethylene food plastic material; the twin-screw extruder has a total of 7 zones, and the temperatures of the 7 zones are 160°C, 165°C, 175°C, 170°C, 170°C, 165°C and 165°C respectively, and the extruder speed is 45r / min. Example 3

[0024] A polyethylene food plastic material comprises the following components by weight: 1% carvacrol beta-cyclodextrin complex, 4% cinnamaldehyde montmorillonite complex, 0.3% antioxidant Irganox 1706, and the balance low-density polyethylene.

[0025] The preparation method is as follows: the materials are blended evenly, then dried at 60°C for 30 minutes, and granulated through a twin-screw extruder to obtain a polyethylene food plastic material; the twin-screw extruder has a total of 7 zones, and the temperatures of the 7 zones are 160°C, 165°C, 175°C, 170°C, 170°C, 165°C and 165°C respectively, and the extruder speed is 45r / min. Example 4

[0026] A polyethylene food plastic material comprises the following components by weight: 4% carvacrol beta-cyclodextrin complex, 1% cinnamaldehyde montmorillonite complex, 0.3% antioxidant Irganox 1706, and the balance low-density polyethylene.

[0027] The preparation method is as follows: the materials are blended evenly, then dried at 60°C for 30 minutes, and granulated through a twin-screw extruder to obtain a polyethylene food plastic material; the twin-screw extruder has a total of 7 zones, and the temperatures of the 7 zones are 160°C, 165°C, 175°C, 170°C, 170°C, 165°C and 165°C respectively, and the extruder speed is 45r / min.

[0028] Comparative Example 1 A polyethylene food plastic material comprises the following components by weight: 5% cinnamaldehyde montmorillonite complex, 0.3% antioxidant Irganox 1706, and the balance low-density polyethylene.

[0029] The preparation method is as follows: the materials are blended evenly, then dried at 60°C for 30 minutes, and granulated through a twin-screw extruder to obtain a polyethylene food plastic material; the twin-screw extruder has a total of 7 zones, and the temperatures of the 7 zones are 160°C, 165°C, 175°C, 170°C, 170°C, 165°C and 165°C respectively, and the extruder speed is 45r / min.

[0030] Comparative Example 2 A polyethylene food plastic material comprises the following components by weight: 5% carvacrol beta-cyclodextrin complex, 0.3% antioxidant Irganox 1706, and the balance low-density polyethylene.

[0031] The preparation method is as follows: the materials are blended evenly, then dried at 60°C for 30 minutes, and granulated through a twin-screw extruder to obtain a polyethylene food plastic material; the twin-screw extruder has a total of 7 zones, and the temperatures of the 7 zones are 160°C, 165°C, 175°C, 170°C, 170°C, 165°C and 165°C respectively, and the extruder speed is 45r / min.

[0032] Comparative Example 3 A polyethylene food plastic material comprises the following components by weight: 3% cinnamaldehyde montmorillonite complex, 0.3% antioxidant Irganox 1706, and the balance low-density polyethylene.

[0033] The preparation method is as follows: the materials are blended evenly, then dried at 60°C for 30 minutes, and granulated through a twin-screw extruder to obtain a polyethylene food plastic material; the twin-screw extruder has a total of 7 zones, and the temperatures of the 7 zones are 160°C, 165°C, 175°C, 170°C, 170°C, 165°C and 165°C respectively, and the extruder speed is 45r / min.

[0034] Comparative Example 4 A polyethylene food plastic material comprises the following components by weight: 2% carvacrol beta-cyclodextrin complex, 0.3% antioxidant Irganox 1706, and the balance low-density polyethylene.

[0035] The preparation method is as follows: the materials are blended evenly, then dried at 60°C for 30 minutes, and granulated through a twin-screw extruder to obtain a polyethylene food plastic material; the twin-screw extruder has a total of 7 zones, and the temperatures of the 7 zones are 160°C, 165°C, 175°C, 170°C, 170°C, 165°C and 165°C respectively, and the extruder speed is 45r / min.

[0036] Test Example 1 The polyethylene food plastic material obtained in each embodiment and comparative example was placed in a casting device for casting into a film. The rotation speed of the casting device was 70 r / min, and the winding speed of the subsequent film was 7.8 r / min, thereby preparing a packaging film.

[0037] Antibacterial performance test: refer to QB / T 2591-2003 "Antibacterial Plastics - Antibacterial Performance Test Method and Antibacterial Effect" (film method) for testing, and test bacteria: Escherichia coli and Staphylococcus aureus. The film sample is placed at room temperature for 10 days, then cleaned and dried before testing.

[0038] Antioxidant migration test: Plastic samples were cut into 12 cm x 12 cm squares. One square was immersed in a wide-mouth bottle containing 200 mL of food simulant, sealed with a rubber stopper, and then transferred to a thermostat for migration testing at various times and temperatures. The food simulant was a 95% ethanol-water solution. 20 was selected to represent room temperature. After 60 hours, 0.5 mL of the immersion solution was sampled for pretreatment prior to loading. The treated solution was then analyzed by high-performance liquid chromatography.

[0039] Antioxidant migration rate = mass of antioxidant in food simulant / mass of food simulant.

[0040] Table 1 Performance test Staphylococcus aureus inhibition rate / % Escherichia coli inhibition rate / % Antioxidant mobility 60h / mg / kg Example 1 93.1 92.4 0.00197 Example 2 94.9 94.7 0.00192 Example 3 93.3 91.4 0.00193 Example 4 92.4 91.3 0.00194 Comparative Example 1 92.6 92.8 0.00224 Comparative Example 2 92.5 92.9 0.00229 Comparative Example 3 91.6 91.3 0.00225 Comparative Example 4 91.4 91.7 0.00226 As can be seen from Table 1, when the carvacrol β-cyclodextrin complex and the cinnamaldehyde montmorillonite complex are added simultaneously to polyethylene, not only good inhibition against Staphylococcus aureus and Escherichia coli is exhibited, but also better antioxidant migration rate is achieved compared to Comparative Examples 1 to 4, and the migration of antioxidants in the packaging material into the food simulant is inhibited.

[0041] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A polyethylene food plastic material, characterized in that: The invention comprises the following components by weight percentage: 1% to 5% of carvacrol beta-cyclodextrin complex, 1% to 5% of cinnamaldehyde montmorillonite complex, 0.3% of antioxidant, and the balance being low-density polyethylene.

2. The polyethylene food plastic material according to claim 1, wherein: The invention comprises the following components by weight percentage: 2% carvacrol beta-cyclodextrin complex, 3% cinnamaldehyde montmorillonite complex, 0.3% antioxidant, and the balance being low-density polyethylene.

3. The polyethylene food plastic material according to claim 2, wherein: The antioxidant is selected from Irganox1706.

4. The polyethylene food plastic material according to claim 3, wherein: The preparation method of the carvacrol β-cyclodextrin complex is as follows: 5 g of β-cyclodextrin and 50 mL of a 2:1 water / ethanol mixed solution were placed in a reactor and stirred at 55°C for 10 minutes to obtain a β-cyclodextrin solution. Subsequently, a 10% (v / v) carvacrol solution was prepared with ethanol. The carvacrol solution was added dropwise to the β-cyclodextrin solution and stirred at 55°C for 30 minutes. The solution was stirred for 4 hours until the temperature dropped to 25°C. The precipitate was recovered by vacuum filtration and dried at room temperature for 24 hours to obtain a carvacrol-β-cyclodextrin complex.

5. The polyethylene food plastic material according to claim 4, wherein: The mass ratio of the β-cyclodextrin to carvacrol is 80:

20.

6. The polyethylene food plastic material according to claim 3, wherein: Preparation method of the cinnamaldehyde montmorillonite complex: Dissolve 3 g of methylcellulose, 0.9 g of polyethylene glycol, and 1.5 g of cinnamaldehyde in a mixture of 33 mL of water and 66 mL of ethanol and stir for 0.5 h to obtain solution A. Disperse montmorillonite in 25 mL of water and stir for 0.5 h to obtain solution B; Solution B was slowly added to solution A, stirred at room temperature for 4 h, and then dried at 60° C. for 24 h to obtain a cinnamaldehyde-montmorillonite complex.

7. The polyethylene food plastic material according to claim 6, wherein: The mass ratio of the montmorillonite to cinnamaldehyde is 1.5:0.

2.

8. The method for preparing a polyethylene food plastic material according to any one of claims 1 to 7, wherein: The method comprises the following steps: uniformly blending the materials, drying them at 60° C. for 30 minutes, and granulating them through a twin-screw extruder to obtain polyethylene food plastic material.

9. The method for preparing the polyethylene food plastic material as claimed in claim 8, wherein: The twin-screw extruder has 7 zones in total, the temperatures of the 7 zones are 160°C, 165°C, 175°C, 170°C, 170°C, 165°C and 165°C in sequence, and the extruder speed is 45r / min.