Anti-mildew plastic for packaging container and preparation method of anti-mildew plastic

Abstract

The invention discloses anti-mildew plastic for a packaging container and a preparation method of the anti-mildew plastic, and relates to the technical field of plastic. The plastic is prepared from the modified biochar and the modified polyethylene; wherein 3, 5-diformylphenylboronic acid, 5-nitro-2-(oxiranyl methoxy) acetophenone, ethynyl magnesium bromide, isobutyldichlorosilane, hydroxylamine hydrochloride, ammonium salt and 3-butenyl chloroformate are used for synthesizing an anti-aging substance, then the anti-aging substance and polyethylene are subjected to cross-linking modification, an ultraviolet absorption group, a silicon-carbon bond and a boron-carbon bond are introduced into a polyethylene side chain, and the anti-aging substance is prepared. While the photo-thermal aging of the plastic is prevented, the barrier property of the plastic is improved; the biochar is modified by aminopropyl methyl dimethoxysilane, N, N-diethyl-p-aminobenzaldehyde, 11-chlorodecanoic acid and chitosan, antibacterial groups are generated on the surface of the biochar, and the biochar and modified polyethylene can be stacked in order, so that movement of water vapor and oxygen is prevented, and the anti-mildew effect of the plastic is improved.

Description

Technical Field

[0001] This invention relates to the field of plastics technology, specifically to an anti-mildew plastic for packaging containers and its preparation method. Background Technology

[0002] Due to its lightweight, ease of processing, corrosion resistance, and abundant resources, plastic is ubiquitous in our daily lives and has gradually replaced glass bottles, becoming the primary material in the cosmetics packaging market. In recent years, plastic packaging has accounted for more than 80% of cosmetics packaging materials. Currently, the main materials used in cosmetic plastic packaging containers include polyethylene, polypropylene (PP), polyethylene terephthalate, and polyvinyl chloride. When flexible materials are required for cosmetic packaging bottles, polyethylene is more commonly used.

[0003] Consumers use cosmetics for a relatively long period. During this time, the coating on cosmetic packaging bottles has low barrier properties and poor antibacterial ability, allowing external moisture, oxygen, or bacteria to gradually migrate through the packaging bottle into the cosmetics inside, causing contamination and mold growth. Furthermore, polyethylene, due to its molecular structure, is highly susceptible to light and heat, causing it to age and significantly shortening the shelf life of cosmetics. Summary of the Invention

[0004] The purpose of this invention is to provide an anti-mildew plastic for packaging containers and a method for preparing the same, so as to solve the problems existing in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an anti-mildew plastic for packaging containers, wherein the anti-mildew plastic for packaging containers mainly includes modified biochar and modified polyethylene.

[0006] Furthermore, the modified biochar is prepared from sheet biochar, aminopropylmethyldimethoxysilane, N,N-diethyl-p-aminobenzaldehyde, 11-chlorodecanoic acid, and chitosan.

[0007] Furthermore, the modified polyethylene is prepared from 3,5-dicarboxyphenylboronic acid, 5-nitro-2-(epoxyethylene methoxy)acetophenone, ethynyl magnesium bromide, isobutyldichlorosilane, hydroxylamine hydrochloride, ammonium salt, 3-butenyl chloroformate, and polyethylene.

[0008] Furthermore, a method for preparing a mildew-resistant plastic for packaging containers includes the following preparation steps:

[0009] (1) Mix organosilicon compound, N,N-dimethylacetamide, hydroxylamine hydrochloride and ferric chloride in a mass ratio of 1:4:0.4:0.6 to 1:7:0.6:0.6, react at 100°C for 2 to 4 hours, pour in ice water at 30 times the mass of organosilicon compound, let stand for 30 minutes, filter, and dry at 60°C for 7 hours to obtain nitrile compound;

[0010] (2) Anhydrous methanol, sodium methoxide, and nitrile compound were mixed in a mass ratio of 4:0.3:1 to 6:0.3:1. The mixture was stirred at 30°C and 70 rpm for 5 to 8 hours. Then, ammonium chloride (0.4 to 0.6 times the mass of the nitrile compound) and acetic acid (0.4 times the mass of the nitrile compound) were added. The mixture was stirred at 60°C for 7 to 10 hours. After cooling to room temperature, the mixture was filtered, and the filter cake was washed with methanol 6 times. The cake was then dried at 50°C and vacuum degree -0.08 MPa for 8 hours to obtain formamidin compound.

[0011] (3) At 0℃, potassium carbonate aqueous solution, formamidin compound, ethyl acetate and 3-butenyl chloroformate were mixed in a mass ratio of 5:1:4:0.8 to 7:1:5:1.2. The mass ratio of potassium carbonate to deionized water in the potassium carbonate aqueous solution was 3:7. After stirring at 60 to 100 rpm for 1.5 h, the mixture was separated. The organic layer was washed 4 times with saturated sodium chloride solution and distilled at 80℃ for 2 to 3 h to obtain intermediate A.

[0012] (4) Linear low-density polyethylene, intermediate A, and 2,5-dimethyl-2,5-bis-(tert-butylperoxy)hexane are mixed in a mass ratio of 10:1:0.03 to 40:1:0.03, stirred at 950 rpm for 3 to 6 minutes, and then extruded at 180 to 210°C to obtain modified polyethylene.

[0013] (5) Oxidized biochar, aminopropylmethyldimethoxysilane, and toluene were mixed in a mass ratio of 1:0.8:24 to 1:1.1:24. Under nitrogen protection, the mixture was reacted at 110°C and 80 rpm for 10 to 14 hours. After filtration, the mixture was washed five times with dichloromethane and ethanol, and dried at 80°C for 24 hours to obtain silanized biochar. Silanized biochar, N,N-diethyl-p-aminobenzaldehyde, and methanol were mixed in a mass ratio of 1:1:70 to 1:2:75. After stirring at 70°C and 70 rpm for 7 to 9 hours, the mixture was filtered. After washing three times with methanol and distilled water, the mixture was dried at -0.09 MPa and 80°C for 8 hours to obtain Schiff base biochar.

[0014] (6) Tetrahydrofuran, 11-chlorodecanoic acid, and Schiff base biochar were mixed in a mass ratio of 3:0.5:1 to 3:0.7:1 and reacted at 35-40℃ and 100rpm for 3-4 hours. After filtration, the mixture was dried at 80℃ for 24 hours to obtain quaternized biochar. Chitosan and acetic acid solution were mixed in a mass ratio of 1:132. The mass ratio of acetic acid to deionized water in the acetic acid solution was 1:99. The mixture was stirred until it became viscous. Quaternized biochar with a mass ratio of 0.8-2.0 times that of chitosan was added. The mixture was stirred at 55-60℃ and 100rpm for 1-3 hours. After filtration, the mixture was frozen at -30 to -18℃ for 12 hours and dried at 60℃ for 24 hours to obtain modified biochar.

[0015] (7) Mix modified polyethylene, modified biochar, dioctyl phthalate and ethylene octene copolymer, extrude at 200-250°C, and granulate to obtain anti-mildew plastic for packaging containers.

[0016] Further, the preparation method of the organosilicon compound in step (1) is as follows: acetonitrile and chalcone compound are mixed in a mass ratio of 2:1 to 4:1 and placed in an ice-water bath. A silicon solution with a mass ratio of 2 to 4 times that of the chalcone compound is added at a rate of 0.3 to 0.5 mL / min. The mass ratio of isobutyldichlorosilane to acetonitrile in the silicon solution is 1:1.2. The ice-water bath is removed, the temperature is raised to 70°C, and the temperature is maintained for 3 to 5 hours. Then, the temperature is cooled to 0°C, and an acetylenoid magnesium bromide solution with a mass ratio of 4 to 7 times that of the chalcone compound is added. The mass ratio of acetylenoid magnesium bromide to acetonitrile in the acetylenoid magnesium bromide solution is 1:5. The reaction is carried out at room temperature for 4 to 6 hours, and then the temperature is raised to 85 to 90°C and the reaction is maintained for 4 to 6 hours to obtain the organosilicon compound.

[0017] Furthermore, the preparation method of the chalcone compound is as follows: 3,5-dicarboxyphenylboronic acid, 5-nitro-2-(epoxyethylene methoxy)acetophenone, ethanol, and a 10% sodium hydroxide solution are mixed and reacted for 7-9 hours. Then, deionized water is added until a precipitate forms. The mixture is allowed to stand at 4°C for 7-9 hours, filtered, and the filter cake is washed three times with deionized water. The cake is then dried at -0.08 MPa and 40°C for 12 hours to obtain the chalcone compound.

[0018] Furthermore, the mass ratio of 3,5-dicarboxyphenylboronic acid, 5-nitro-2-(epoxyethylene methoxy)acetophenone, ethanol, and 10% sodium hydroxide solution is 1:0.3:19:3 to 1:0.4:26:4.

[0019] Further, the preparation method of the oxidized biochar in step (5) is as follows: place the sheet biochar in nitric acid with a mass fraction of 10-30% at 42 times the mass of the sheet biochar, then place it in a water bath at 80°C, react for 2-4 hours, filter, take the filter cake, add distilled water at 142 times the mass of the sheet biochar, heat at 80-90°C for 15 minutes, filter, repeat the above operation 4 times, and dry at 105°C for 24 hours to obtain oxidized biochar.

[0020] Furthermore, the preparation method of the flake biochar is as follows: grapefruit peel powder is immersed in a 5% sodium hydroxide solution with a mass fraction of 1 to 3 times the weight of grapefruit peel powder for 10 to 13 hours, then filtered, washed with deionized water until the pH of the washing solution is 7, dried at 60°C for 12 hours, placed in an alumina crucible, wrapped with tin foil and placed in a tube furnace, calcined at 600°C for 1 to 2 hours, then cooled to room temperature and removed, washed 4 times with 1% hydrochloric acid, and dried at 60°C for 18 hours to obtain flake biochar.

[0021] Furthermore, the mass ratio of the modified polyethylene, modified biochar, dioctyl phthalate, and ethylene octene copolymer in step (7) is 40:12:5:20 to 60:24:5:40.

[0022] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0023] This invention utilizes modified biochar and modified polyethylene co-extruded to produce plastics for use in cosmetic packaging, achieving anti-mildew and anti-aging effects.

[0024] First, this invention utilizes the formyl group of 3,5-dicarboxyphenylboronic acid to react with the ketone group of 5-nitro-2-(epoxyethylene methoxy)acetophenone to form a chalcone structure, which effectively absorbs ultraviolet light, prevents photoaging of plastics, and gives the plastics anti-aging properties. Next, the epoxy group of 5-nitro-2-(epoxyethylene methoxy)acetophenone, ethynyl magnesium bromide, and chloride ions of isobutyldichlorosilane react to introduce silicon-carbon bonds and boron-carbon bonds, improving the thermal stability of the plastics and preventing thermo-oxidative aging. Furthermore, during extrusion, the hydrosilylation between triple bonds and silicon-hydrogen bonds, as well as the synthesis reaction between triple bonds, causes the plastics to crosslink and form a three-dimensional network. Simultaneously, silicon and boron can react with oxygen in the air to form inorganic compounds such as silicon dioxide and boron oxide, thus forming an isolation layer at the gas-solid interface to prevent air from eroding the inner structure and improve the plastic's thermal aging and mildew resistance. Then, the remaining unreacted formyl groups of 3,5-diformylphenylboronic acid react with hydroxylamine hydrochloride to form nitrile groups, which then form a formamidinium structure with ammonium salts. This structure, together with chalcone, enhances the plastic's photoaging effect. The amino group of formamidinium then reacts with the chloride ions of 3-butenyl chloroformate, and its double bond crosslinks with polyethylene, grafting into the polyethylene molecular chain, improving the compatibility between the two and enhancing the plastic's aging resistance.

[0025] Secondly, this invention utilizes alkali activation-calcination of grapefruit peel to produce sheet-like biochar containing abundant internal pores, capable of adsorbing molten modified polyethylene. This allows the biochar and plastic to be uniformly and orderly integrated into an organic-inorganic composite film, forming a layered structure that prevents external air from entering and achieves an anti-mildew effect. Then, aminopropylmethyldimethoxysilane is grafted onto the surface of the biochar via silicon-oxygen bonds. Its amino group reacts with the aldehyde group of N,N-diethyl-p-aminobenzaldehyde to generate a Schiff base structure, which can effectively inhibit bacterial growth and improve the anti-mildew effect of the plastic. Finally, the chloride ions of 11-chlorodecanoic acid react with the N,N-diethyl... The amino group of 1,1-aminobenzaldehyde reacts with the amino group to form a quaternary ammonium structure, which, together with the Schiff base structure, enhances the antibacterial properties of the plastic. At the same time, the long-chain alkyl group wraps around the biochar, preventing moisture from entering the plastic and enhancing its resistance to mildew. Then, the carboxyl group of 1,1-chlorodecanoic acid reacts with the amino group of chitosan to form an externally hydrophilic and internally hydrophobic structure. When in contact with moisture and oxygen, the chitosan molecule contains a large number of oxygen atoms, which can form a large number of hydrogen bonds, thereby preventing the movement of moisture and oxygen. At the same time, the internal hydrophobicity prevents moisture from penetrating further, greatly improving the barrier properties of the plastic and thus enhancing its resistance to mildew. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] To more clearly illustrate the method provided by the present invention, the following embodiments are provided in detail. The test methods for various indicators of the anti-mildew plastic for packaging containers produced in the following embodiments are as follows:

[0028] Aging resistance: Example and comparative samples of the same size were subjected to artificial aging tests according to GB / T 7141, aged at 90℃ for 1000 hours, and the tensile strength before and after aging was measured; ultraviolet aging tests were conducted according to ASTM G155, with a radiation energy of 0.35 W / m². 2 @340nm, cycle time is 102 minutes dry, 18 minutes wet, test time is 500h.

[0029] Anti-mildew: The melt obtained by melt extrusion of the examples and comparative examples was formed on a casting equipment, and then stretched in a direction at 180°C with a transverse stretching ratio of 2 times and a longitudinal stretching ratio of 4 times to obtain a plastic film. The oxygen permeability was tested according to GB / T 1038, the water vapor permeability was tested according to GB / T 1037, and the antibacterial rate of Escherichia coli and Staphylococcus aureus was tested according to QB / T2591.

[0030] Example 1

[0031] (1) 3,5-dicarboxyphenylboronic acid, 5-nitro-2-(epoxyethylene methoxy)acetophenone, ethanol, and 10% sodium hydroxide solution were mixed in a mass ratio of 1:0.3:19:3. After reacting for 7 h, deionized water was added until a precipitate formed. The mixture was allowed to stand at 4 °C for 7 h, filtered, and the filter cake was washed three times with deionized water. The mixture was then dried at 40 °C under a vacuum of -0.08 MPa for 12 h to obtain the chalcone compound.

[0032] (2) Acetonitrile and chalcone compound were mixed at a mass ratio of 2:1 and placed in an ice-water bath. A silicon solution with a mass ratio of 2 times that of the chalcone compound was added at a rate of 0.3 mL / min. The mass ratio of isobutyldichlorosilane to acetonitrile in the silicon solution was 1:1.2. The ice-water bath was removed, the temperature was raised to 70°C, and the temperature was maintained for 3 hours. The temperature was then cooled to 0°C, and an acetylenoid magnesium bromide solution with a mass ratio of 4 times that of the chalcone compound was added. The mass ratio of acetylenoid magnesium bromide to acetonitrile in the acetylenoid magnesium bromide solution was 1:5. The reaction was carried out at room temperature for 4 hours, and the temperature was raised to 85°C and the reaction was maintained for 4 hours to obtain the organosilicon compound.

[0033] (3) Mix organosilicon compound, N,N-dimethylacetamide, hydroxylamine hydrochloride and ferric chloride in a mass ratio of 1:4:0.4:0.6, react at 100°C for 2 hours, pour in ice water with a mass of 30 times that of organosilicon compound, let stand for 30 minutes, filter, and dry at 60°C for 7 hours to obtain nitrile compound.

[0034] (4) Anhydrous methanol, sodium methoxide and nitrile compound were mixed in a mass ratio of 4:0.3:1 and stirred at 30°C and 70 rpm for 5 h. Then, ammonium chloride and acetic acid with a mass of 0.4 times that of the nitrile compound were added. The mixture was stirred at 60°C for 7 h. After cooling to room temperature, the mixture was filtered and the filter cake was washed with methanol 6 times. The cake was dried at 50°C and vacuum degree -0.08 MPa for 8 h to obtain formamidin compound.

[0035] (5) At 0℃, potassium carbonate aqueous solution, formamidin compound, ethyl acetate and 3-butenyl chloroformate were mixed in a mass ratio of 5:1:4:0.8. The mass ratio of potassium carbonate to deionized water in the potassium carbonate aqueous solution was 3:7. After stirring at 60 rpm for 1.5 h, the mixture was separated. The organic layer was washed 4 times with saturated sodium chloride solution and distilled at 80℃ for 2 h to obtain intermediate A.

[0036] (6) Linear low-density polyethylene, intermediate A and 2,5-dimethyl-2,5-bis-(tert-butylperoxy)hexane are mixed in a mass ratio of 10:1:0.03, stirred at 950 rpm for 3 min and then extruded at 180-210℃ to obtain modified polyethylene.

[0037] (7) Soak grapefruit peel powder in a 5% sodium hydroxide solution with a mass fraction equal to the weight of grapefruit peel powder for 10 hours, filter, wash with deionized water until the pH of the washing solution is 7, dry at 60°C for 12 hours, place in an alumina crucible, wrap the crucible with tin foil and place it in a tube furnace, calcine at 600°C for 1 hour, cool to room temperature and take out, wash with 1% hydrochloric acid 4 times, and dry at 60°C for 18 hours to obtain flaky biochar.

[0038] (8) Place the sheet biochar in 10% nitric acid at a mass fraction of 42 times the mass of the sheet biochar, and then place it in an 80°C water bath. After reacting for 2 hours, filter, take the filter cake, add distilled water at a mass fraction of 142 times the mass of the sheet biochar, heat at 80°C for 15 minutes, filter, repeat the above operation 4 times, and dry at 105°C for 24 hours to obtain oxidized biochar.

[0039] (9) Oxidized biochar, aminopropylmethyldimethoxysilane and toluene were mixed in a mass ratio of 1:0.8:24, and reacted at 110°C and 80 rpm for 10 h under nitrogen protection. After filtration, the mixture was washed 5 times with dichloromethane and ethanol in sequence, and dried at 80°C for 24 h to obtain silanized biochar.

[0040] (10) Silanized biochar, N,N-diethyl-p-aminobenzaldehyde and methanol were mixed in a mass ratio of 1:1:70, stirred at 70℃ and 70rpm for 7h, filtered, washed with methanol and distilled water three times in sequence, and dried at -0.09MPa and 80℃ for 8h to obtain Schiff base biochar.

[0041] (11) Tetrahydrofuran, 11-chlorodecanoic acid, and Schiff base biochar were mixed at a mass ratio of 3:0.5:1, reacted at 35°C and 100 rpm for 3 h, filtered, and dried at 80°C for 24 h to obtain quaternized biochar; chitosan and acetic acid solution were mixed at a mass ratio of 1:132, with the mass ratio of acetic acid to deionized water in the acetic acid solution being 1:99, stirred until viscous, and quaternized biochar with a mass of 0.8 times the mass of chitosan was added. After stirring at 55°C and 100 rpm for 1 h, filtered, frozen at -30°C for 12 h, and dried at 60°C for 24 h to obtain modified biochar;

[0042] (12) Mix modified polyethylene, modified biochar, dioctyl phthalate and ethylene octene copolymer in a mass ratio of 40:12:5:20, extrude at 200-250℃, and granulate to obtain anti-mildew plastic for packaging containers.

[0043] Example 2

[0044] (1) 3,5-dicarboxyphenylboronic acid, 5-nitro-2-(epoxyethylene methoxy)acetophenone, ethanol, and 10% sodium hydroxide solution were mixed in a mass ratio of 1:0.35:22.5:3.5. After reacting for 8 hours, deionized water was added until a precipitate formed. The mixture was allowed to stand at 4°C for 8 hours, filtered, and the filter cake was washed three times with deionized water. The cake was then dried at 40°C under a vacuum of -0.08 MPa for 12 hours to obtain the chalcone compound.

[0045] (2) Acetonitrile and chalcone compound were mixed at a mass ratio of 3:1 and placed in an ice-water bath. Silicon solution with a mass ratio of 3 times that of chalcone compound was added at a rate of 0.4 mL / min. The mass ratio of isobutyldichlorosilane to acetonitrile in the silicon solution was 1:1.2. The ice-water bath was removed, the temperature was raised to 70°C, and the temperature was maintained for 4 hours. Then the temperature was cooled to 0°C, and acetylenol magnesium bromide solution with a mass ratio of 5.5 times that of chalcone compound was added. The mass ratio of acetylenol magnesium bromide to acetonitrile in the acetylenol magnesium bromide solution was 1:5. The reaction was carried out at room temperature for 5 hours, and then the temperature was raised to 88°C and the reaction was maintained for 5 hours to obtain organosilicon compound.

[0046] (3) Mix organosilicon compound, N,N-dimethylacetamide, hydroxylamine hydrochloride and ferric chloride in a mass ratio of 1:5.5:0.5:0.6, react at 100°C for 3 hours, pour in ice water with a mass of 30 times that of organosilicon compound, let stand for 30 minutes, filter, and dry at 60°C for 7 hours to obtain nitrile compound.

[0047] (4) Anhydrous methanol, sodium methoxide, and nitrile compound were mixed in a mass ratio of 5:0.3:1 and stirred at 30°C and 70 rpm for 6.5 h. Then, ammonium chloride (0.5 times the mass of the nitrile compound) and acetic acid (0.4 times the mass of the nitrile compound) were added. The mixture was stirred at 60°C for 8.5 h. After cooling to room temperature, the mixture was filtered, and the filter cake was washed with methanol 6 times and dried at 50°C and vacuum degree -0.08 MPa for 8 h to obtain formamidin compound.

[0048] (5) At 0℃, potassium carbonate aqueous solution, formamidin compound, ethyl acetate and 3-butenyl chloroformate were mixed in a mass ratio of 6:1:4.5:1. The mass ratio of potassium carbonate to deionized water in the potassium carbonate aqueous solution was 3:7. After stirring at 80 rpm for 1.5 h, the mixture was separated. The organic layer was washed 4 times with saturated sodium chloride solution and distilled at 80℃ for 2.5 h to obtain intermediate A.

[0049] (6) Linear low-density polyethylene, intermediate A and 2,5-dimethyl-2,5-bis-(tert-butylperoxy)hexane are mixed in a mass ratio of 25:1:0.03, stirred at 950 rpm for 4 min and then extruded at 180-210℃ to obtain modified polyethylene.

[0050] (7) Soak grapefruit peel powder in a 5% sodium hydroxide solution with a mass fraction of 2 times the weight of grapefruit peel powder for 11.5 hours. After soaking, filter, wash with deionized water until the pH of the washing solution is 7, dry at 60°C for 12 hours, place in an alumina crucible, wrap the crucible with tin foil and place it in a tube furnace. Calcine at 600°C for 1.5 hours, then cool to room temperature and take out. Wash with 1% hydrochloric acid 4 times and dry at 60°C for 18 hours to obtain flaky biochar.

[0051] (8) Place the sheet biochar in 20% nitric acid at a mass fraction of 42 times the mass of the sheet biochar, and then place it in a water bath at 80°C. After reacting for 3 hours, filter, take the filter cake, add distilled water at a mass fraction of 142 times the mass of the sheet biochar, heat at 85°C for 15 minutes, filter, repeat the above operation 4 times, and dry at 105°C for 24 hours to obtain oxidized biochar.

[0052] (9) Oxidized biochar, aminopropylmethyldimethoxysilane and toluene were mixed in a mass ratio of 1:0.95:24, and reacted at 110°C and 80 rpm for 12 h under nitrogen protection. After filtration, the mixture was washed 5 times with dichloromethane and ethanol in sequence, and dried at 80°C for 24 h to obtain silanized biochar.

[0053] (10) Silanized biochar, N,N-diethyl-p-aminobenzaldehyde and methanol were mixed in a mass ratio of 1:1.5:72.5, stirred at 70℃ and 70rpm for 8h, filtered, washed with methanol and distilled water three times in sequence, and dried at -0.09MPa and 80℃ for 8h to obtain Schiff base biochar.

[0054] (11) Tetrahydrofuran, 11-chlorodecanoic acid, and Schiff base biochar were mixed at a mass ratio of 3:0.6:1 and reacted at 37°C and 100 rpm for 3.5 h. After filtration, the mixture was dried at 80°C for 24 h to obtain quaternized biochar. Chitosan and acetic acid solution were mixed at a mass ratio of 1:132. The mass ratio of acetic acid to deionized water in the acetic acid solution was 1:99. The mixture was stirred until it became viscous. Quaternized biochar with a mass ratio of 1.4 times that of chitosan was added. The mixture was stirred at 58°C and 100 rpm for 2 h. After filtration, the mixture was frozen at -24°C for 12 h and dried at 60°C for 24 h to obtain modified biochar.

[0055] (12) Mix modified polyethylene, modified biochar, dioctyl phthalate and ethylene octene copolymer in a mass ratio of 50:18:5:30, extrude at 200-250℃, and granulate to obtain anti-mildew plastic for packaging containers.

[0056] Example 3

[0057] (1) 3,5-dicarboxyphenylboronic acid, 5-nitro-2-(epoxyethylene methoxy)acetophenone, ethanol, and 10% sodium hydroxide solution were mixed in a mass ratio of 1:0.4:26:4. After reacting for 9 hours, deionized water was added until a precipitate formed. The mixture was allowed to stand at 4°C for 9 hours, filtered, and the filter cake was washed three times with deionized water. The cake was then dried at 40°C under a vacuum of -0.08 MPa for 12 hours to obtain the chalcone compound.

[0058] (2) Acetonitrile and chalcone compound were mixed at a mass ratio of 4:1 and placed in an ice-water bath. Silicon solution with a mass ratio of 4 times that of chalcone compound was added at a rate of 0.5 mL / min. The mass ratio of isobutyldichlorosilane to acetonitrile in the silicon solution was 1:1.2. The ice-water bath was removed, the temperature was raised to 70°C, and the temperature was maintained for 5 h. Then the temperature was cooled to 0°C, and acetylenol magnesium bromide solution with a mass ratio of 7 times that of chalcone compound was added. The mass ratio of acetylenol magnesium bromide to acetonitrile in the acetylenol magnesium bromide solution was 1:5. The reaction was carried out at room temperature for 6 h, and the temperature was raised to 90°C and the reaction was maintained for 6 h to obtain organosilicon compound.

[0059] (3) Mix organosilicon compound, N,N-dimethylacetamide, hydroxylamine hydrochloride and ferric chloride in a mass ratio of 1:7:0.6:0.6, react at 100°C for 4 hours, pour in ice water with a mass of 30 times that of organosilicon compound, let stand for 30 minutes, filter, and dry at 60°C for 7 hours to obtain nitrile compound.

[0060] (4) Anhydrous methanol, sodium methoxide, and nitrile compound were mixed in a mass ratio of 6:0.3:1 and stirred at 30°C and 70 rpm for 8 hours. Then, ammonium chloride (0.6 times the mass of the nitrile compound) and acetic acid (0.4 times the mass of the nitrile compound) were added. The mixture was stirred at 60°C for 10 hours. After cooling to room temperature, the mixture was filtered, and the filter cake was washed with methanol 6 times. The cake was dried at 50°C and vacuum degree -0.08 MPa for 8 hours to obtain formamidin compound.

[0061] (5) At 0℃, potassium carbonate aqueous solution, formamidin compound, ethyl acetate and 3-butenyl chloroformate were mixed in a mass ratio of 7:1:5:1.2. The mass ratio of potassium carbonate to deionized water in the potassium carbonate aqueous solution was 3:7. After stirring at 100 rpm for 1.5 h, the mixture was separated. The organic layer was washed 4 times with saturated sodium chloride solution and distilled at 80℃ for 2-3 h to obtain intermediate A.

[0062] (6) Linear low-density polyethylene, intermediate A and 2,5-dimethyl-2,5-bis-(tert-butylperoxy)hexane are mixed in a mass ratio of 40:1:0.03, stirred at 950 rpm for 6 min and then extruded at 180-210℃ to obtain modified polyethylene.

[0063] (7) Soak grapefruit peel powder in a 5% sodium hydroxide solution with a mass fraction of 3 times the weight of grapefruit peel powder for 13 hours. After soaking, filter, wash with deionized water until the pH of the washing solution is 7, dry at 60°C for 12 hours, place in an alumina crucible, wrap the crucible with tin foil and place it in a tube furnace. Calcine at 600°C for 2 hours, then cool to room temperature and take out. Wash with 1% hydrochloric acid 4 times and dry at 60°C for 18 hours to obtain flaky biochar.

[0064] (8) Place the sheet biochar in 30% nitric acid at a mass fraction of 42 times the mass of the sheet biochar, and then place it in an 80°C water bath. After reacting for 4 hours, filter, take the filter cake, add distilled water at a mass fraction of 142 times the mass of the sheet biochar, heat at 90°C for 15 minutes, filter, repeat the above operation 4 times, and dry at 105°C for 24 hours to obtain oxidized biochar.

[0065] (9) Oxidized biochar, aminopropylmethyldimethoxysilane and toluene were mixed in a mass ratio of 1:1.1:24, and reacted at 110°C and 80 rpm for 14 h under nitrogen protection. After filtration, the mixture was washed 5 times with dichloromethane and ethanol in sequence, and dried at 80°C for 24 h to obtain silanized biochar.

[0066] (10) Silanized biochar, N,N-diethyl-p-aminobenzaldehyde and methanol were mixed in a mass ratio of 1:2:75, stirred at 70℃ and 70rpm for 9h, filtered, washed with methanol and distilled water three times in sequence, and dried at -0.09MPa and 80℃ for 8h to obtain Schiff base biochar.

[0067] (11) Tetrahydrofuran, 11-chlorodecanoic acid, and Schiff base biochar were mixed at a mass ratio of 3:0.7:1 and reacted at 40°C and 100 rpm for 4 h. After filtration, the mixture was dried at 80°C for 24 h to obtain quaternized biochar. Chitosan and acetic acid solution were mixed at a mass ratio of 1:132. The mass ratio of acetic acid to deionized water in the acetic acid solution was 1:99. The mixture was stirred until it became viscous. Quaternized biochar with a mass of twice the mass of chitosan was added. The mixture was stirred at 60°C and 100 rpm for 3 h. After filtration, the mixture was frozen at -18°C for 12 h and dried at 60°C for 24 h to obtain modified biochar.

[0068] (12) Mix modified polyethylene, modified biochar, dioctyl phthalate and ethylene octene copolymer in a mass ratio of 60:24:5:40, extrude at 200-250℃, and granulate to obtain anti-mildew plastic for packaging containers.

[0069] Comparative Example 1

[0070] The difference between Comparative Example 1 and Example 2 is that step (1) is omitted, and step (2) is changed to: acetonitrile and 3,5-dicarboxyphenylboronic acid are mixed at a mass ratio of 4:1 and placed in an ice-water bath. A silicon solution with a mass ratio of 4 times that of 3,5-dicarboxyphenylboronic acid is added at a rate of 0.5 mL / min. The mass ratio of isobutyldichlorosilane to acetonitrile in the silicon solution is 1:1.2. The ice-water bath is removed, the temperature is raised to 70°C, and the temperature is maintained for 5 hours. Then, the temperature is cooled to 0°C, and an acetylenyl magnesium bromide solution with a mass ratio of 7 times that of 3,5-dicarboxyphenylboronic acid is added. The mass ratio of acetylenyl magnesium bromide to acetonitrile in the acetylenyl magnesium bromide solution is 1:5. The reaction is carried out at room temperature for 6 hours, then the temperature is raised to 90°C and the reaction is maintained for 6 hours to obtain the organosilicon compound. The remaining steps are the same as in Example 2.

[0071] Comparative Example 2

[0072] The difference between Comparative Example 2 and Example 2 is that step (2) is omitted, and step (3) is changed to: mixing chalcone compound, N,N-dimethylacetamide, hydroxylamine hydrochloride, and ferric chloride in a mass ratio of 1:5.5:0.5:0.6, reacting at 100°C for 3 hours, then adding ice water at 30 times the mass of the chalcone compound, letting it stand for 30 minutes, filtering, and drying at 60°C for 7 hours to obtain a nitrile compound. The remaining steps are the same as in Example 2.

[0073] Comparative Example 3

[0074] The difference between Comparative Example 3 and Example 2 is that steps (3) to (5) are omitted, and step (6) is changed to: linear low-density polyethylene, organosilicon compound, and 2,5-dimethyl-2,5-bis-(tert-butylperoxy)hexane are mixed at a mass ratio of 25:1:0.03, stirred at 950 rpm for 4 min, and then extruded at 180-210°C to obtain modified polyethylene. The remaining steps are the same as in Example 2.

[0075] Comparative Example 4

[0076] The difference between Comparative Example 4 and Example 2 is that step (10) is omitted, and step (11) is changed to: mixing tetrahydrofuran, 11-chlorodecanoic acid, and silanized biochar at a mass ratio of 3:0.6:1, reacting at 37°C and 100 rpm for 3.5 h, filtering, and drying at 80°C for 24 h to obtain quaternized biochar; mixing chitosan and acetic acid solution at a mass ratio of 1:132, with the mass ratio of acetic acid to deionized water in the acetic acid solution being 1:99, stirring until viscous, adding quaternized biochar at 1.4 times the mass of chitosan, stirring at 58°C and 100 rpm for 2 h, filtering, freezing at -24°C for 12 h, and drying at 60°C for 24 h to obtain modified biochar. The remaining steps are the same as in Example 2.

[0077] Comparative Example 5

[0078] The difference between Comparative Example 5 and Example 2 lies in step (11). Step (11) is changed to: mixing chitosan and acetic acid solution at a mass ratio of 1:132, with the mass ratio of acetic acid to deionized water in the acetic acid solution being 1:99, stirring until viscous, adding Schiff base biochar at 1.4 times the mass of chitosan, stirring at 58°C and 100 rpm for 2 hours, filtering, freezing at -24°C for 12 hours, and drying at 60°C for 24 hours to obtain modified biochar. The remaining steps are the same as in Example 2.

[0079] Comparative Example 6

[0080] The difference between Comparative Example 6 and Example 2 lies in step (11). Step (11) is changed to: mixing tetrahydrofuran, 11-chlorodecanoic acid, and Schiff base biochar at a mass ratio of 3:0.6:1, reacting at 37°C and 100 rpm for 3.5 h, filtering, and drying at 80°C for 24 h to obtain modified biochar. The remaining steps are the same as in Example 2.

[0081] Example of effect

[0082] Table 1 below shows the performance analysis results of the anti-mildew plastics for packaging containers using Examples 1 to 3 and Comparative Examples 1 to 6 of the present invention.

[0083] Table 1

[0084]

[0085]

[0086] A comparison of the tensile strength test data before and after aging in the examples and comparative examples reveals that the present invention utilizes 3,5-dicarboxyphenylboronic acid, 5-nitro-2-(epoxyethylene methoxy)acetophenone, ethynyl magnesium bromide, isobutyldichlorosilane, hydroxylamine hydrochloride, ammonium salt, and 3-butenyl chloroformate to synthesize an anti-aging substance, which is then crosslinked with polyethylene for modification. Chalcone and formamidinium are introduced into the polyethylene side chain, working together to effectively absorb ultraviolet light and prevent photoaging of the plastic. Furthermore, silicon-carbon bonds and boron-carbon bonds are introduced to improve the thermal stability of the plastic and prevent thermo-oxidative aging. A comparison of the transmittance and antibacterial rate test data between the examples and comparative examples reveals that during the modified polyethylene extrusion process, the hydrosilylation between the triple bonds and silane-hydrogen bonds in the side chain and the synthesis reaction between the triple bonds... The process involves cross-linking the plastic to form a three-dimensional network system. Simultaneously, silicon and boron elements react with oxygen in the air to form inorganic compounds such as silicon dioxide and boron oxide, thus creating an isolation layer at the gas-solid interface to prevent air from eroding the inner structure. Then, using aminopropylmethyldimethoxysilane, N,N-diethyl-p-aminobenzaldehyde, 11-chlorodecanoic acid, and chitosan-modified biochar, antibacterial groups are generated on the surface of the biochar. These groups can be stacked in an orderly manner with modified polyethylene to form an externally hydrophilic and internally hydrophobic structure. The external chitosan forms numerous hydrogen bonds with water vapor and oxygen, preventing their movement. At the same time, the internal hydrophobicity hinders further water vapor penetration, greatly improving the barrier properties of the plastic and thus enhancing its resistance to mold growth.

[0087] It will be apparent to those skilled in the art that the present 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 its spirit or essential characteristics. 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. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A mildew-resistant plastic for packaging containers, characterized in that, The anti-mildew plastics used in the packaging containers mainly include modified biochar and modified polyethylene.

2. The anti-mildew plastic for packaging containers according to claim 1, characterized in that, The modified biochar is prepared from sheet biochar, aminopropylmethyldimethoxysilane, N,N-diethyl-p-aminobenzaldehyde, 11-chlorodecanoic acid, and chitosan.

3. The anti-mildew plastic for packaging containers according to claim 2, characterized in that, The modified polyethylene is prepared from 3,5-dicarboxyphenylboronic acid, 5-nitro-2-(epoxyethylene methoxy)acetophenone, ethynyl magnesium bromide, isobutyldichlorosilane, hydroxylamine hydrochloride, ammonium salt, 3-butenyl chloroformate, and polyethylene.

4. A method for preparing anti-mildew plastic for packaging containers, characterized in that, The preparation steps include the following: (1) Mix organosilicon compound, N,N-dimethylacetamide, hydroxylamine hydrochloride and ferric chloride in a mass ratio of 1:4:0.4:0.6 to 1:7:0.6:0.6, react at 100°C for 2 to 4 hours, pour in ice water at 30 times the mass of organosilicon compound, let stand for 30 minutes, filter, and dry at 60°C for 7 hours to obtain nitrile compound; (2) Anhydrous methanol, sodium methoxide, and nitrile compound were mixed in a mass ratio of 4:1:0.3 to 6:0.3:

1. The mixture was stirred at 30°C and 70 rpm for 5 to 8 hours. Then, ammonium chloride (0.4 to 0.6 times the mass of the nitrile compound) and acetic acid (0.4 times the mass of the nitrile compound) were added. The mixture was stirred at 60°C for 7 to 10 hours. After cooling to room temperature, the mixture was filtered. The filter cake was washed with methanol 6 times and dried at 50°C and vacuum degree -0.08 MPa for 8 hours to obtain formamidin compound. (3) At 0℃, potassium carbonate aqueous solution, formamidin compound, ethyl acetate and 3-butenyl chloroformate were mixed in a mass ratio of 5:1:4:0.8 to 7:1:5:1.

2. The mass ratio of potassium carbonate to deionized water in the potassium carbonate aqueous solution was 3:

7. After stirring at 60 to 100 rpm for 1.5 h, the mixture was separated. The organic layer was washed 4 times with saturated sodium chloride solution and distilled at 80℃ for 2 to 3 h to obtain intermediate A. (4) Linear low-density polyethylene, intermediate A, and 2,5-dimethyl-2,5-bis-(tert-butylperoxy)hexane are mixed in a mass ratio of 10:1:0.03 to 40:1:0.03, stirred at 950 rpm for 3 to 6 minutes, and then extruded at 180 to 210°C to obtain modified polyethylene. (5) Oxidized biochar, aminopropylmethyldimethoxysilane, and toluene were mixed in a mass ratio of 1:0.8:24 to 1:1.1:

24. Under nitrogen protection, the mixture was reacted at 110°C and 80 rpm for 10 to 14 hours. After filtration, the mixture was washed five times with dichloromethane and ethanol, and dried at 80°C for 24 hours to obtain silanized biochar. Silanized biochar, N,N-diethyl-p-aminobenzaldehyde, and methanol were mixed in a mass ratio of 1:1:70 to 1:2:

75. After stirring at 70°C and 70 rpm for 7 to 9 hours, the mixture was filtered. After washing three times with methanol and distilled water, the mixture was dried at -0.09 MPa and 80°C for 8 hours to obtain Schiff base biochar. (6) Tetrahydrofuran, 11-chlorodecanoic acid, and Schiff base biochar were mixed in a mass ratio of 3:0.5:1 to 3:0.7:1 and reacted at 35-40℃ and 100rpm for 3-4 hours. After filtration, the mixture was dried at 80℃ for 24 hours to obtain quaternized biochar. Chitosan and acetic acid solution were mixed in a mass ratio of 1:

132. The mass ratio of acetic acid to deionized water in the acetic acid solution was 1:

99. The mixture was stirred until it became viscous. Quaternized biochar with a mass ratio of 0.8-2.0 times that of chitosan was added. The mixture was stirred at 55-60℃ and 100rpm for 1-3 hours. After filtration, the mixture was frozen at -30 to -18℃ for 12 hours and dried at 60℃ for 24 hours to obtain modified biochar. (7) Mix modified polyethylene, modified biochar, dioctyl phthalate and ethylene octene copolymer, extrude at 200-250°C, and granulate to obtain anti-mildew plastic for packaging containers.

5. The method for preparing an anti-mildew plastic for packaging containers according to claim 4, characterized in that, The preparation method of the organosilicon compound in step (1) is as follows: acetonitrile and chalcone compound are mixed in a mass ratio of 2:1 to 4:1 and placed in an ice-water bath. A silicon solution with a mass ratio of 2 to 4 times that of the chalcone compound is added at a rate of 0.3 to 0.5 mL / min. The mass ratio of isobutyldichlorosilane to acetonitrile in the silicon solution is 1:1.

2. The ice-water bath is removed, the temperature is raised to 70°C, and the temperature is maintained for 3 to 5 hours. Then, the temperature is cooled to 0°C, and an acetylenoid magnesium bromide solution with a mass ratio of 4 to 7 times that of the chalcone compound is added. The mass ratio of acetylenoid magnesium bromide to acetonitrile in the acetylenoid magnesium bromide solution is 1:

5. The reaction is carried out at room temperature for 4 to 6 hours, and then the temperature is raised to 85 to 90°C and the reaction is maintained for 4 to 6 hours to obtain the organosilicon compound.

6. The method for preparing an anti-mildew plastic for packaging containers according to claim 5, characterized in that, The method for preparing the chalcone compound is as follows: 3,5-dicarboxyphenylboronic acid, 5-nitro-2-(epoxyethylene methoxy)acetophenone, ethanol, and a 10% sodium hydroxide solution are mixed and reacted for 7-9 hours. Then, deionized water is added until a precipitate forms. The precipitate is allowed to stand at 4°C for 7-9 hours, filtered, and the filter cake is washed three times with deionized water. The precipitate is then dried at -0.08 MPa and 40°C for 12 hours to obtain the chalcone compound.

7. The method for preparing an anti-mildew plastic for packaging containers according to claim 6, characterized in that, The mass ratio of 3,5-dicarboxyphenylboronic acid, 5-nitro-2-(epoxyethylene methoxy)acetophenone, ethanol, and 10% sodium hydroxide solution is 1:0.3:19:3 to 1:0.4:26:

4.

8. The method for preparing an anti-mildew plastic for packaging containers according to claim 4, characterized in that, The preparation method of oxidized biochar in step (5) is as follows: place the sheet biochar in nitric acid with a mass fraction of 10-30% at 42 times the mass of the sheet biochar, and then place it in a water bath at 80℃. After reacting for 2-4 hours, filter, take the filter cake, add distilled water at 142 times the mass of the sheet biochar, heat at 80-90℃ for 15 minutes, filter, repeat the above operation 4 times, and dry at 105℃ for 24 hours to obtain oxidized biochar.

9. A method for preparing an anti-mildew plastic for packaging containers according to claim 8, characterized in that, The method for preparing the flake biochar is as follows: grapefruit peel powder is immersed in a 5% sodium hydroxide solution with a mass fraction of 1 to 3 times the weight of the grapefruit peel powder for 10 to 13 hours. After immersion, the solution is filtered, washed with deionized water until the pH of the washing solution is 7, dried at 60°C for 12 hours, placed in an alumina crucible, wrapped with tin foil, and placed in a tube furnace. After calcination at 600°C for 1 to 2 hours, the solution is cooled to room temperature and removed. The solution is washed four times with 1% hydrochloric acid and dried at 60°C for 18 hours to obtain flake biochar.

10. A method for preparing an anti-mildew plastic for packaging containers according to claim 4, characterized in that, The mass ratio of the modified polyethylene, modified biochar, dioctyl phthalate, and ethylene octene copolymer in step (7) is 40:12:5:20 to 60:24:5:40.

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