Preparation method of antibacterial degradable plastic
By quaternizing the 4-(dimethylamino)-2-butenoyl chloride and grafting it on the starch surface, and modifying the polypropylene resin with modified polylactic fiber, the problems of existing antibacterial plastic materials in manufacturing and environmental degradation are solved, and efficient antibacterial and degradable plastic materials are achieved.
Patent Information
- Application Number
- CN202510223518.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-22
- Publication Date
- 2025-06-06
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The existing antibacterial plastics are prone to discoloration, difficult to manufacture, and easily agglomerate in plastics, and cannot exert better antibacterial properties. At the same time, the plastic materials are not degradable, resulting in environmental pollution.
By quaternizing the 4-(dimethylamino)-2-butenoyl chloride, and grafting the acyl chloride group on the surface of the starch, the starch is positively charged, adsorbed on microbial cells, and its growth environment is changed, thereby achieving the purpose of bactericidal and antibacterial. At the same time, the modified polylactic fiber is modified to improve the degradation performance and antibacterial properties of the plastic.
It realizes the efficient antibacterial and degradability of plastics, improves the mechanical properties and interface binding capabilities of plastics, and enhances its degradability in the environment.
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of plastics, in particular to a method for preparing antibacterial and degradable plastics. Background Art
[0002] Plastic raw materials are synthetic polymer compounds that can be molded into various shapes and can keep the same shape. Plastics are closely related to people's daily lives. They are convenient and durable. However, most of the raw materials of plastics are non-degradable materials. When plastics are discarded in nature, the waste plastics decompose very slowly in nature. It takes decades or even hundreds of years to completely decompose.
[0003] At present, the antibacterial agents used in plastics are mainly silver-based inorganic antibacterial agents, which have the advantages of good heat resistance, broad antibacterial spectrum, long effective antibacterial period, low toxicity, and no drug resistance. However, they are easy to discolor, difficult to manufacture, and easy to agglomerate in plastics, and cannot exert better antibacterial properties. Summary of the invention
[0004] The purpose of the present invention is to provide an antibacterial and degradable plastic and a preparation method thereof, so as to solve the problems existing in the prior art.
[0005] In order to solve the above technical problems, the present invention provides the following technical solution: a method for preparing an antibacterial and degradable plastic, comprising the following preparation steps: (1) Mix the short fibers and a sodium hydroxide aqueous solution with a mass concentration of 5-20% in a ratio of 5 g:100 mL, soak for 30-70 min, filter out the fibers, and dry them to obtain pretreated polylactic acid fibers; (2) Pretreated polylactic acid fiber, acetic acid, pyridine and 2-methylmalonyl dichloride were mixed, stirred at 30-60 rpm for 24 h under nitrogen protection, and the fiber was filtered out, washed with deionized water for 3-6 times, and dried at 50°C to constant weight to obtain chlorinated polylactic acid fiber; (3) Soaking the chlorinated polylactic acid fiber in an ascorbic acid solution at a bath ratio of 1:3, stirring at 30-50 rpm for 8-14 hours, filtering the fiber, and drying at 60°C to constant weight to obtain a modified polylactic acid fiber precursor; (4) Soaking the modified polylactic acid fiber precursor and cuprous chloride aqueous solution at a bath ratio of 1:5 for 5 to 8 hours, filtering out the fiber, washing it thoroughly with water, and then drying it at 60°C for 2 to 5 hours to obtain the modified polylactic acid fiber; (5) Stir and dissolve soluble starch and dimethyl sulfoxide in a ratio of 5g:100mL, place in a constant temperature oil bath at 105°C, add quaternized 4-(dimethylamino)-2-butenoyl chloride 3 to 5 times the mass of the soluble starch under stirring at 50 to 60rpm, add triethylamine after complete dissolution, react for 2 to 4h, add anhydrous ethanol 5 times the volume of dimethyl sulfoxide for precipitation and separation, centrifuge, take the solid, wash with anhydrous ethanol 3 to 5 times, and dry at 50°C and vacuum degree 0.085MPa for 10h to obtain modified starch; (6) Mix polypropylene resin, modified starch, modified polylactic acid fiber and initiator in a mass ratio of 100:10-20:5-10:1-3, extrude and granulate at 160-180°C to obtain plastic masterbatch; mix plastic masterbatch, paraffin oil, sodium stearate and calcium stearate in a mass ratio of 100:1-3:1-3:1-3, extrude and granulate at 160-180°C, and injection mold to obtain plastic.
[0006] Furthermore, the short fibers in step (1) are polylactic acid fibers with a length of 0.5 to 2.0 mm.
[0007] Furthermore, in step (2), the ratio of the pretreated polylactic acid fiber, acetic acid, pyridine, and 2-methylmalonyl dichloride is 1-3 g: 100 mL: 0.01-0.03 g: 0.2-1.0 g.
[0008] Furthermore, the ascorbic acid solution in step (3) is a mixture of an ascorbic acid aqueous solution with a mass fraction of 10-33% and triethylamine in a volume ratio of 2:0.5-0.8.
[0009] Furthermore, the soaking in step (4) is performed at 55°C throughout the entire process.
[0010] Furthermore, the concentration of the cuprous chloride aqueous solution in step (4) is 20-50 mg / L.
[0011] Furthermore, the preparation method of the quaternized 4-(dimethylamino)-2-butenoyl chloride in step (5) is as follows: dichloromethane and 1-chlorobutane are mixed and dissolved in a ratio of 50 mL:1.6-2.5 g, 4-(dimethylamino)-2-butenoyl chloride in an amount of 0.7-1.1 times the mass of 1-chlorobutane is added at 30-40 rpm, and then placed in a water bath at 35° C., reacted for 5-7 hours, and then vacuum distilled in a water bath at 60° C. with a vacuum degree of 0.085 MPa until no solvent is present.
[0012] Furthermore, in step (5), the molar ratio of triethylamine to quaternized 4-(dimethylamino)-2-butenoyl chloride is 1:1.
[0013] Furthermore, the centrifugal separation conditions in step (5) are a rotation speed of 2000 r / min and a separation time of 10 min.
[0014] Furthermore, the initiator in step (6) is one or more of dibenzoyl peroxide, azobisisobutyronitrile, and diisopropylbenzene peroxide.
[0015] Compared with the prior art, the beneficial effects achieved by the present invention are: The invention performs quaternization modification on 4-(dimethylamino)-2-butenoyl chloride and then utilizes the acyl chloride group to graft on the starch surface, so that the starch is positively charged and adsorbed on the negatively charged microbial cells, thereby changing the charge environment necessary for the growth and reproduction of the microbial cells, thereby achieving the purpose of sterilization and bacteriostasis. Then, the polypropylene resin is modified with the modified polylactic acid fiber to obtain a plastic master batch. The double bonds of the modified starch copolymerize with the polypropylene, and the modified starch can be connected to the polypropylene side chain, thereby improving the degradation performance of the polypropylene matrix and improving the compatibility of the starch with the polypropylene matrix, so that the three have better interface bonding ability, so that the modified starch can fill more fiber and plastic master batch gaps, so that the internal molecular network of the prepared plastic is more three-dimensional, and the strength of the plastic is effectively improved. The fibers are interwoven in the polymer plastic, which greatly improves the strength of the plastic. The presence of the polylactic acid and the starch greatly improves the degradability of the plastic.
[0016] The invention utilizes the acyl halide group of 2-methylmalonyl dichloride to graft the alkalized polylactic acid short fibers, controls the material ratio, makes the fiber surface contain acyl halide groups, thereby making ascorbic acid grafted on the fiber surface, improves the hydrophilicity of the polylactic acid short fibers, promotes the interface compatibility with starch, avoids the separation state in the melt extrusion process, and is beneficial to improve the mechanical properties of the plastic. At the same time, the modified polylactic acid fiber molecular chain contains multiple metal coordination sites, which can chelate copper ions, and the grafted ascorbic acid has reducing properties, which can realize the in-situ reduction of copper ions on the surface of the polylactic acid fibers, thereby making Cu 2 O is firmly loaded on the polylactic acid fiber, thereby improving the antibacterial property of the modified polylactic acid fiber and then improving the antibacterial property of the plastic. DETAILED DESCRIPTION
[0017] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0018] In order to more clearly illustrate the method provided by the present invention, the following examples are used to describe in detail the test methods of various indicators of the antibacterial and degradable plastics prepared in the following examples are as follows: Antibacterial: Cut the plastic into discs with a radius of 0.5 cm, and then 7 The E. coli suspension of 100 CFU / mL was added to the phosphate buffer solution, and the disc sample was added, and the mixture was shaken at room temperature for 3 hours, and 2 mL of the solution was taken as the experimental group solution. The E. coli suspension was added to the phosphate buffer solution, shaken evenly, and then 2 mL of the solution was taken as the blank group solution. The E. coli experimental group solution and the blank group solution were inoculated in a plate by agar pouring method, and cultured at 37C for 24 hours. The experiment was repeated 3 times, and the viable bacteria culture counts were performed after culture, and the average value was taken.
[0019] Antibacterial rate = (number of colonies in the blank group - colony efficiency in the experimental group) / number of colonies in the blank group × 100% Degradability: Referring to GB / T16716.7-2012 standard, the composting degradation rate of degradable plastics was tested after 3 months.
[0020] Strength: Tested in accordance with GB / T1040-2018 standard, tensile loading rate 5mm / min.
[0021] Example 1 (1) Cutting polylactic acid fibers into short fibers with a length of 0.5 mm; mixing the short fibers and a sodium hydroxide aqueous solution with a mass concentration of 5% in a ratio of 5 g:100 mL, soaking for 70 minutes, filtering out the fibers, and drying them to obtain pretreated polylactic acid fibers; (2) Pretreated polylactic acid fiber, acetic acid, pyridine, and 2-methylmalonyl dichloride were mixed in a ratio of 1 g:100 mL:0.01 g:0.2 g, stirred at 30 rpm for 24 h under nitrogen protection, filtered out the fiber, washed with deionized water for 3 times, and dried at 50 °C to constant weight to obtain chlorinated polylactic acid fiber; (3) After uniformly mixing a 10% ascorbic acid aqueous solution and triethylamine in a volume ratio of 2:0.5, immerse the chlorinated polylactic acid fiber in the above solution, stir at 30 rpm for 8 h, filter out the fiber, and dry at 60 ° C to constant weight to obtain a modified polylactic acid fiber precursor; (4) Soaking the modified polylactic acid fiber precursor and 20 mg / L cuprous chloride aqueous solution at a bath ratio of 1:5 for 5 h at 55 °C, filtering out the fiber, washing it thoroughly with water, and drying it at 60 °C for 2 h to obtain the modified polylactic acid fiber; (5) Dissolve dichloromethane and 1-chlorobutane in a ratio of 50 mL:1.6 g, add 4-(dimethylamino)-2-butenoyl chloride (0.7 times the mass of 1-chlorobutane) at 30 rpm, and then place in a 35°C water bath. After reacting for 5-7 hours, distill under reduced pressure in a water bath at 60°C with a vacuum degree of 0.085 MPa until no solvent is present, to obtain quaternized 4-(dimethylamino)-2-butenoyl chloride; (6) Stir and dissolve soluble starch and dimethyl sulfoxide in a ratio of 5g:100mL, place in a constant temperature oil bath at 105°C, add quaternized 4-(dimethylamino)-2-butenoyl chloride in an amount 3 times the mass of the soluble starch under stirring at 50rpm, and after complete dissolution, add triethylamine in a molar ratio of triethylamine to quaternized 4-(dimethylamino)-2-butenoyl chloride of 1:1. After reacting for 2h, add anhydrous ethanol in an amount 5 times the volume of dimethyl sulfoxide for precipitation and separation, centrifuge at a speed of 2000r / min for 10min, take the solid, wash it with anhydrous ethanol 3 times, and dry it at 50°C and a vacuum degree of 0.085MPa for 10h to obtain modified starch; (7) Polypropylene resin, modified starch, modified polylactic acid fiber, and dibenzoyl peroxide are mixed in a mass ratio of 100:10:5:1, extruded at 160-180°C, and granulated to obtain a plastic masterbatch; plastic masterbatch, paraffin oil, sodium stearate, and calcium stearate are mixed in a mass ratio of 100:1:1:1, extruded at 160-180°C, granulated, and injection molded to obtain a plastic.
[0022] Example 2 (1) Cutting polylactic acid fibers into short fibers with a length of 1.2 mm; mixing the short fibers and a sodium hydroxide aqueous solution with a mass concentration of 10% in a ratio of 5 g:100 mL, soaking for 50 min, filtering out the fibers, and drying them to obtain pretreated polylactic acid fibers; (2) Pretreated polylactic acid fiber, acetic acid, pyridine, and 2-methylmalonyl dichloride were mixed in a ratio of 2 g:100 mL:0.02 g:0.6 g, stirred at 45 rpm for 24 h under nitrogen protection, filtered out the fiber, washed with deionized water for 4 times, and dried at 50 ° C to constant weight to obtain chlorinated polylactic acid fiber; (3) After uniformly mixing a 22% ascorbic acid aqueous solution and triethylamine in a volume ratio of 2:0.66, chlorinated polylactic acid fibers were immersed in the solution, stirred at 40 rpm for 10 h, and then the fibers were filtered out and dried at 60° C. to constant weight to obtain a modified polylactic acid fiber precursor; (4) Soaking the modified polylactic acid fiber precursor and 30 mg / L cuprous chloride aqueous solution at a bath ratio of 1:5 for 6.5 h at 55 °C, filtering out the fiber, washing it thoroughly with water, and drying it at 60 °C for 3 h to obtain the modified polylactic acid fiber; (5) Mix and dissolve dichloromethane and 1-chlorobutane in a ratio of 50 mL:1.9 g, add 4-(dimethylamino)-2-butenoyl chloride (0.9 times the mass of 1-chlorobutane) at 30-40 rpm, and then place in a 35°C water bath. After reacting for 6 hours, distill under reduced pressure in a water bath at a vacuum degree of 0.085 MPa and 60°C until no solvent is present to obtain quaternized 4-(dimethylamino)-2-butenoyl chloride; (6) Stir and dissolve soluble starch and dimethyl sulfoxide in a ratio of 5g:100mL, place in a constant temperature oil bath at 105°C, add quaternized 4-(dimethylamino)-2-butenoyl chloride in an amount 4 times the mass of the soluble starch under stirring at 55rpm, and after complete dissolution, add triethylamine in a molar ratio of triethylamine to quaternized 4-(dimethylamino)-2-butenoyl chloride of 1:1. After reacting for 3h, add anhydrous ethanol in an amount 5 times the volume of dimethyl sulfoxide for precipitation and separation, centrifuge at a speed of 2000r / min for 10min, take the solid, wash it with anhydrous ethanol 4 times, and dry it at 50°C and a vacuum degree of 0.085MPa for 10h to obtain modified starch; (7) Polypropylene resin, modified starch, modified polylactic acid fiber and azobisisobutyronitrile are mixed in a mass ratio of 100:15:7:2, extruded at 160-180°C, granulated to obtain plastic masterbatch; plastic masterbatch, paraffin oil, sodium stearate and calcium stearate are mixed in a mass ratio of 100:2:2:2, extruded at 160-180°C, granulated and injection molded to obtain plastic.
[0023] Example 3 (1) Cutting polylactic acid fibers into short fibers with a length of 2.0 mm; mixing the short fibers and a sodium hydroxide aqueous solution with a mass concentration of 20% in a ratio of 5 g:100 mL, soaking for 30 minutes, filtering out the fibers, and drying them to obtain pretreated polylactic acid fibers; (2) Pretreated polylactic acid fiber, acetic acid, pyridine, and 2-methylmalonyl dichloride were mixed in a ratio of 3 g:100 mL:0.03 g:1.0 g, stirred at 60 rpm for 24 h under nitrogen protection, filtered out the fiber, washed with deionized water for 6 times, and dried at 50 ° C to constant weight to obtain chlorinated polylactic acid fiber; (3) After uniformly mixing a 33% ascorbic acid aqueous solution and triethylamine in a volume ratio of 2:0.8, chlorinated polylactic acid fibers were immersed in the above solution, stirred at 50 rpm for 14 h, and then the fibers were filtered out and dried at 60 ° C to constant weight to obtain a modified polylactic acid fiber precursor; (4) Soaking the modified polylactic acid fiber precursor and 50 mg / L cuprous chloride aqueous solution at a bath ratio of 1:5 for 8 h at 55 °C, filtering out the fiber, washing it thoroughly with water, and drying it at 60 °C for 5 h to obtain the modified polylactic acid fiber; (5) Mix and dissolve dichloromethane and 1-chlorobutane in a ratio of 50 mL:2.5 g, add 4-(dimethylamino)-2-butenoyl chloride (1.1 times the mass of 1-chlorobutane) at 40 rpm, and then place in a 35°C water bath. After reacting for 7 hours, distill under reduced pressure in a water bath at a vacuum degree of 0.085 MPa and 60°C until no solvent is present to obtain quaternized 4-(dimethylamino)-2-butenoyl chloride; (6) Stir and dissolve soluble starch and dimethyl sulfoxide in a ratio of 5g:100mL, place in a constant temperature oil bath at 105°C, add quaternized 4-(dimethylamino)-2-butenoyl chloride in an amount 5 times the mass of the soluble starch under stirring at 60rpm, and after complete dissolution, add triethylamine in a molar ratio of triethylamine to quaternized 4-(dimethylamino)-2-butenoyl chloride of 1:1. After reacting for 4h, add anhydrous ethanol in an amount 5 times the volume of dimethyl sulfoxide for precipitation and separation, centrifuge at a speed of 2000r / min for 10min, take the solid, wash it with anhydrous ethanol 5 times, and dry it at 50°C and a vacuum degree of 0.085MPa for 10h to obtain modified starch; (7) Polypropylene resin, modified starch, modified polylactic acid fiber, and dicumyl peroxide are mixed in a mass ratio of 100:20:10:3, extruded at 160-180°C, and granulated to obtain a plastic masterbatch; plastic masterbatch, paraffin oil, sodium stearate, and calcium stearate are mixed in a mass ratio of 100:3:3:3, extruded at 160-180°C, granulated, and injection molded to obtain a plastic.
[0024] Comparative Example 1 The only difference between Comparative Example 1 and Example 2 is that 2-methylmalonyl dichloride is not used to perform graft modification treatment on the pretreated polylactic acid fiber.
[0025] Comparative Example 2 The difference between Comparative Example 2 and Example 2 is that ascorbic acid is not used to carry out graft modification treatment on the chlorinated polylactic acid fiber.
[0026] Comparative Example 3 The difference between Comparative Example 3 and Example 2 is that steps (1) to (4) are omitted, and step (7) is changed to: polypropylene resin, modified starch, and azobisisobutyronitrile are mixed in a mass ratio of 100:15:2, extruded at 160-180° C., and granulated to obtain a plastic masterbatch; the plastic masterbatch, paraffin oil, sodium stearate, and calcium stearate are mixed in a mass ratio of 100:2:2:2, extruded at 160-180° C., granulated, and injection molded to obtain a plastic; and the remaining steps are the same as those in Example 2.
[0027] Comparative Example 4 The difference between Comparative Example 4 and Example 2 is that 4-(dimethylamino)-2-butenoyl chloride is not subjected to quaternary ammonium modification treatment.
[0028] Comparative Example 5 The difference between Comparative Example 5 and Example 2 is that there are no steps (5) and (6), and step (7) is changed to: polypropylene resin, starch, modified polylactic acid fiber, and azobisisobutyronitrile are mixed in a mass ratio of 100:15:7:2, extruded at 160-180° C., and granulated to obtain a plastic masterbatch; the plastic masterbatch, paraffin oil, sodium stearate, and calcium stearate are mixed in a mass ratio of 100:2:2:2, extruded at 160-180° C., granulated, and injection molded to obtain a plastic; the remaining steps are the same as in Example 2.
[0029] Comparative Example 6 The difference between Comparative Example 6 and Example 2 is that step (7) is different. Step (7) is changed to: polypropylene resin, modified starch, modified polylactic acid fiber, paraffin oil, sodium stearate and calcium stearate are mixed in a mass ratio of 100:15:7:2:2:2, and the mixture is extruded at 160-180° C., granulated and injection molded to obtain a plastic.
[0030] Effect example Table 1 below shows the performance analysis results of the plastics of Examples 1 to 3 of the present invention and Comparative Examples 1 to 6.
[0031] Table 1 From the comparison of the experimental data of the embodiment and the comparative example, it can be found that the present invention adopts the loading Cu 2 O's modified polylactic acid fiber and quaternized starch are used as modifiers of polypropylene and are co-extruded and modified. The presence of quaternized starch promotes the interfacial compatibility of quaternized starch, modified polylactic acid fiber and polypropylene resin base material, so that the modified starch can fill more gaps between fibers and plastic masterbatch. At the same time, the fibers are entangled and interwoven into a network in the polymer plastic, and the synergistic effect improves the mechanical strength of the plastic. In addition, the presence of polylactic acid and starch greatly improves the degradability and antibacterial ability of the plastic.
[0032] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and scope of the equivalent elements of the claims be included in the invention. Any marking in a claim should not be considered as limiting the claim to which it relates.
Claims
1. A method for preparing an antibacterial and degradable plastic, characterized in that: The method comprises the following preparation steps: (1) Cutting polylactic acid fibers into short fibers with a length of 1.2 mm; mixing the short fibers and a sodium hydroxide aqueous solution with a mass concentration of 10% in a ratio of 5 g:100 mL, soaking for 50 min, filtering out the fibers, and drying them to obtain pretreated polylactic acid fibers; (2) Pretreated polylactic acid fiber, acetic acid, pyridine, and 2-methylmalonyl dichloride were mixed in a ratio of 2 g:100 mL:0.02 g:0.6 g, stirred at 45 rpm for 24 h under nitrogen protection, filtered out the fiber, washed with deionized water for 4 times, and dried at 50 ° C to constant weight to obtain chlorinated polylactic acid fiber; (3) After uniformly mixing a 22% ascorbic acid aqueous solution and triethylamine in a volume ratio of 2:0.66, chlorinated polylactic acid fibers were immersed in the solution, stirred at 40 rpm for 10 h, and then the fibers were filtered out and dried at 60° C. to constant weight to obtain a modified polylactic acid fiber precursor; (4) Soaking the modified polylactic acid fiber precursor and 30 mg / L cuprous chloride aqueous solution at a bath ratio of 1:5 for 6.5 h at 55 °C, filtering out the fiber, washing it thoroughly with water, and drying it at 60 °C for 3 h to obtain the modified polylactic acid fiber; (5) Mix and dissolve dichloromethane and 1-chlorobutane in a ratio of 50 mL:1.9 g, add 4-(dimethylamino)-2-butenoyl chloride (0.9 times the mass of 1-chlorobutane) at 30-40 rpm, and then place in a 35°C water bath. After reacting for 6 hours, distill under reduced pressure in a water bath at a vacuum degree of 0.085 MPa and 60°C until no solvent is present to obtain quaternized 4-(dimethylamino)-2-butenoyl chloride; (6) Stir and dissolve soluble starch and dimethyl sulfoxide in a ratio of 5g:100mL, place in a constant temperature oil bath at 105°C, add quaternized 4-(dimethylamino)-2-butenoyl chloride in an amount 4 times the mass of the soluble starch under stirring at 55rpm, and after complete dissolution, add triethylamine in a molar ratio of triethylamine to quaternized 4-(dimethylamino)-2-butenoyl chloride of 1:
1. After reacting for 3h, add anhydrous ethanol in an amount 5 times the volume of dimethyl sulfoxide for precipitation and separation, centrifuge at a speed of 2000r / min for 10min, take the solid, wash it with anhydrous ethanol 4 times, and dry it at 50°C and a vacuum degree of 0.085MPa for 10h to obtain modified starch; (7) Polypropylene resin, modified starch, modified polylactic acid fiber and azobisisobutyronitrile are mixed in a mass ratio of 100:15:7:2, extruded at 160-180°C, granulated to obtain plastic masterbatch; plastic masterbatch, paraffin oil, sodium stearate and calcium stearate are mixed in a mass ratio of 100:2:2:2, extruded at 160-180°C, granulated and injection molded to obtain plastic.