Degradable packaging composite material and preparation method thereof

Abstract

The invention relates to a degradable packaging composite material and a preparation method thereof, and belongs to the technical field of high polymer materials. The degradable packaging composite material comprises the following components in parts by weight: 50-85 parts of thermoplastic starch, 25-55 parts of polylactic acid, 4-10 parts of a plasticizer, 0.5-6 parts of an antioxidant, 1-12 parts of a lubricant, 4-12 parts of a foaming agent, 1-15 parts of a foaming promoter, 1-3 parts of an antistatic modifier and 1-3 parts of a flame retardant, n-vinyl pyrrolidone polymerized in the antistatic modifier cooperates with quaternary ammonium salt, so that the conductive efficiency is enhanced, graphene oxide forms a conductive network in a matrix, and the tensile strength and the bending strength are improved at the same time; boron and phosphorus of the flame retardant are synergistic, a B-O-C carbon layer is formed at high temperature, flame-retardant gas is released, an S -O system prevents combustion products from escaping, and low-smoke flame retardance is achieved; the degradable packaging composite material prepared by the invention not only has excellent antistatic and flame-retardant effects, but also has good tensile and bending strength.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, and particularly relates to a degradable packaging composite material and a preparation method thereof. Background Art

[0002] With the rapid development of the logistics industry and the continuous improvement of global environmental awareness, consumers' demand for environmentally friendly express delivery bags is increasing day by day. As a packaging material that can be quickly decomposed in the natural environment and effectively reduce environmental pollution, degradable packaging composite materials are gradually favored by the market.

[0003] However, traditional degradable packaging composite materials are prone to accumulating static electricity during use and are difficult to eliminate. This not only causes plastics to adsorb dust in the air and affects aesthetics, but also leads to adhesion problems during the manufacturing process of the materials. In addition, the accumulation of static electricity may not only cause electric shock, equipment failure, but also pose safety hazards such as fires. Therefore, the antistatic problem of composite materials has become crucial; in addition, although degradable packaging composite materials have certain flame retardancy, with the improvement of actual application requirements, their own flame retardancy can no longer meet the needs. Therefore, developing a degradable packaging composite material with excellent performance has important practical significance and application value. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a degradable packaging composite material and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A degradable packaging composite material, comprising the following raw materials in parts by weight: 50 - 85 parts of thermoplastic starch, 25 - 55 parts of polylactic acid, 4 - 10 parts of plasticizer, 0.5 - 6 parts of antioxidant, 1 - 12 parts of lubricant, 4 - 12 parts of foaming agent, 1 - 15 parts of foaming aid, 1 - 3 parts of antistatic modifier, 1 - 3 parts of flame retardant;

[0007] The plasticizer is sodium dodecyl sulfate;

[0008] The antioxidant is antioxidant 1010;

[0009] The lubricant is paraffin wax;

[0010] The foaming agent is azodicarbonamide;

[0011] The foaming aid is zinc oxide.

[0012] The antistatic modifier is prepared by the following method:

[0013] Step A1: Disperse 3-(methacryloyloxy)propyltrimethoxysilane in 50 mL of ethanol-aqueous solution, adjust the pH to 4, stir for 2 h, then add graphene oxide and 450 mL of ethanol-aqueous solution, ultrasonically disperse evenly, react at 60 °C for 6 h, wash, filter by suction, and freeze-dry to obtain Compound 1;

[0014] Furthermore, the dosage ratio of 3-(methacryloyloxy)propyltrimethoxysilane to graphene oxide is 1.0 - 1.5 g : 1.0 - 1.5 g, and the volume ratio of water to ethanol in the ethanol-aqueous solution is 1∶9;

[0015] First, use the hydroxyl groups generated by the hydrolysis of 3-(methacryloyloxy)propyltrimethoxysilane to react with the hydroxyl groups on graphene oxide to form a compound;

[0016] Step A2: Mix p-chloromethylstyrene, trimethylamine, and 2,6-di-tert-butyl-4-methylphenol, heat to 70 °C under a nitrogen atmosphere to react, continue to react for 24 h after heating and stirring for 3 min, wait for the system to cool to 40 °C, wash, filter by suction, and dry in vacuum at 40 °C to obtain Compound 2;

[0017] Furthermore, the mass ratio of p-chloromethylstyrene, trimethylamine, and 2,6-di-tert-butyl-4-methylphenol is 16.1 - 16.5 g : 5.7 - 6.1 g : 0.36 - 0.40 g;

[0018] Secondly, use the chlorine atom of p-chloromethylstyrene to react with the amino group of trimethylamine to carry out quaternization reaction to form Compound 2;

[0019] Step A3: Mix Compound 1, Compound 2, and N-vinylpyrrolidone, stir for 10 min, then add azobisisobutyronitrile and acetonitrile and mix evenly, react in a constant-temperature oil bath at 70 °C for 3 h, and dry in vacuum at room temperature to obtain an antistatic modifier;

[0020] Furthermore, the dosage ratio of Compound 1, Compound 2, N-vinylpyrrolidone, azobisisobutyronitrile, and acetonitrile is 5 - 7 g : 2 - 4 g : 4 - 10 mL : 0.35 - 0.55 g : 2 mL;

[0021] Finally, use the carbon-carbon double bonds of Compound 1, Compound 2, and N-vinylpyrrolidone to carry out copolymerization to synthesize an antistatic modifier.

[0022] The flame retardant is prepared by the following method:

[0023] Step B1: Mix ethanol and 3-aminopropyltrimethoxysilane and stir for 30 min. Then add benzaldehyde and absolute ethanol and mix. After stirring at 80 °C for 10 h, add 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and stir for 12 h. Cool to room temperature, filter, wash, and dry in vacuum at 80 °C for 6 h to obtain a pre-product;

[0024] Furthermore, the dosage ratio of ethanol, 3-aminopropyltrimethoxysilane, benzaldehyde, absolute ethanol, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 200 mL: 8.95 - 17.91 g: 5.3 - 10.6 g: 250 mL: 0.05 - 0.1 mol;

[0025] First, use the aldehyde group of benzaldehyde to react with the amino group of 3-aminopropyltrimethoxysilane to form an imine bond, and then introduce the flame retardant 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to synthesize the pre-product;

[0026] Step B2: Mix the pre-product and an ethanol-water mixed solution at 35 °C for 10 min. Then add xylene and phenylboronic acid and continue to react at 100 °C for 5 h. After the reaction, wash with water until neutral and perform vacuum filtration to obtain the flame retardant;

[0027] Furthermore, the dosage ratio of the pre-product, ethanol-water mixed solution, xylene, and phenylboronic acid is 0.04 - 0.06 mol: 150 mL: 20 - 45 mL: 5 - 7.4 g; the volume ratio of ethanol to water in the ethanol-water mixed solution is 4:1.

[0028] Secondly, use the silanol groups hydrolyzed from methylvinyldimethoxysilane to react with the hydroxyl groups of phenylboronic acid to synthesize the flame retardant.

[0029] A preparation method of a degradable packaging composite material specifically includes the following steps:

[0030] S1. Knead thermoplastic starch, polylactic acid, plasticizer, lubricant, foaming agent, foaming aid, antistatic modifier, and flame retardant for 30 - 50 min at a kneading temperature of 240 °C. Cool and pulverize to obtain base material particles;

[0031] S2. Melt the base material particles and antioxidant, and perform co-mixing injection molding to obtain the degradable packaging composite material. The melting injection temperature is 160 °C and the system pressure is 6 Mpa.

[0032] The beneficial effects of the present invention:

[0033] The degradable packaging composite material of the present invention uses polylactic acid as the matrix, has good degradable effect, and also adds a flame retardant and a macromolecular polymer antistatic modifier, endowing the composite material with excellent antistatic modification performance and flame retardancy, and effectively extending the service life of the material.

[0034] The antistatic modifier prepared by the present invention, with the advantages of its macromolecular polymer, exhibits antistatic performance superior to that of traditional small-molecule antistatic modifiers. In the antistatic modifier, the quaternary ammonium salt compound enhances hydrophilicity, promotes moisture absorption, and the ions in the water film after moisture absorption act as conductive media to accelerate the transfer and dissipation of charges, effectively avoiding the negative impact of static electricity on production and product quality; at the same time, the polymerized N-vinylpyrrolidone contains hydrophilic groups, which cooperate with the quaternary ammonium salt compound to enhance the conductive efficiency of ions on the material surface and reduce static charge accumulation; in addition, the layered structure and oxygen-containing functional groups of graphene oxide are easily dispersed in the material matrix to form a conductive network, effectively conducting static charges and preventing static charge accumulation. In addition, graphene oxide has high strength and good dispersibility, which can significantly improve the tensile strength and flexural strength of the material, further improve the toughness of the material, and make it not easy to break when subjected to external forces.

[0035] The -Si-O- crosslinking system formed in the flame retardant prepared by the present invention effectively prevents the escape of combustion products and inhibits the thermal degradation of polymer materials, realizing low-smoke flame retardancy; the boron-based component is dehydrated and carbonized when heated at the initial stage of combustion to form a glassy protective layer to prevent the spread of combustion. Its aromatic boric acid group forms a boron-oxygen network structure when heated, and is further transformed into a highly stable B-O-C carbon layer at high temperature. At the same time, non-combustible gases are released to expand the carbon layer, forming a heat-insulating and oxygen-isolating barrier, significantly improving the flame retardancy performance; in addition, boron and phosphorus cooperate to effectively reduce the generation of smoke. Especially the phosphorus-nitrogen flame retardant 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, as a phosphaphenanthrene compound with high thermal stability, can effectively retard fire in the condensed phase and gas phase, promote the formation of a dense and continuous carbon layer, isolate oxygen and heat exchange, and further enhance the flame retardant effect; in addition, the modified flame retardant prepared by the present invention is halogen-free, which helps to reduce environmental pollution and damage to the ecosystem, is harmless to human health, and realizes sustainable development. Specific embodiments

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0037] Example 1: A preparation method of a degradable packaging composite material specifically includes the following steps:

[0038] S1. Weigh the raw materials by parts by weight: 50 parts of thermoplastic starch, 25 parts of polylactic acid, 4 parts of plasticizer, 0.5 part of antioxidant, 1 part of lubricant, 4 parts of foaming agent, 1 part of foaming aid, 1 part of antistatic modifier (prepared in this example), and 1 part of flame retardant (prepared in this example); Mix thermoplastic starch, polylactic acid, sodium dodecyl sulfate, paraffin, azodicarbonamide, zinc oxide, antistatic modifier and flame retardant for 30 min at a mixing temperature of 240 °C, cool and crush to obtain base material particles.

[0039] S2. Melt the base material particles and antioxidant 1010, and carry out co - blending injection molding to obtain a degradable packaging composite material. The melting injection temperature is 160 °C and the system pressure is 6 Mpa.

[0040] The antistatic modifier is prepared by the following method:

[0041] Step A1: Disperse 1.0 g of 3 - (methacryloyloxy) propyltrimethoxysilane in 50 mL of ethanol - aqueous solution, adjust the pH to 4, stir for 2 h, then add 1.0 g of graphene oxide and 450 mL of ethanol - aqueous solution, ultrasonically disperse evenly, react at 60 °C for 6 h, wash, filter by suction and freeze - dry to obtain Compound 1. The volume ratio of water to ethanol in the ethanol - aqueous solution is 1:9.

[0042] Step A2: Mix 16.1 g of p - chloromethylstyrene, 5.7 g of trimethylamine and 0.36 g of 2,6 - di - tert - butyl - 4 - methylphenol, heat up to 70 °C for reaction under a nitrogen atmosphere, continue to react for 24 h after heating and stirring for 3 min, wait for the system to cool to 40 °C, wash, filter by suction, and vacuum - dry at 40 °C to obtain Compound 2.

[0043] Step A3: Mix 5 g of Compound 1, 2 g of Compound 2 and 4 mL of N - vinylpyrrolidone, stir for 10 min, then add 0.35 g of azobisisobutyronitrile and 2 mL of acetonitrile and mix evenly, react in a constant - temperature oil bath at 70 °C for 3 h, and vacuum - dry at room temperature to obtain the antistatic modifier.

[0044] The flame retardant is prepared by the following method:

[0045] Step B1: Mix 200 mL of ethanol and 8.95 g of 3 - aminopropyltrimethoxysilane and stir for 30 min, then add 5.3 g of benzaldehyde and 250 mL of absolute ethanol, stir at 80 °C for 10 h, then add 0.05 mol of 9,10 - dihydro - 9 - oxa - 10 - phosphaphenanthrene - 10 - oxide, stir for 12 h, cool to room temperature, filter, wash, and vacuum - dry at 80 °C for 6 h to obtain the pre - product.

[0046] Step B2: Mix 0.04 mol of the pre-product and 150 mL of the ethanol-water mixed solution at 35 °C for 10 min, then add 20 mL of xylene and 5 g of phenylboronic acid, and continue the reaction at 100 °C for 5 h. After the reaction, wash with water until neutral, and perform vacuum filtration to obtain the flame retardant. The volume ratio of ethanol to water in the ethanol-water mixed solution is 4:1.

[0047] Example 2: A preparation method of a degradable packaging composite material specifically includes the following steps:

[0048] S1. Weigh the raw materials by weight: 62 parts of thermoplastic starch, 40 parts of polylactic acid, 7 parts of plasticizer, 3 parts of antioxidant, 6.5 parts of lubricant, 8 parts of foaming agent, 8 parts of foaming aid, 2 parts of antistatic modifier (prepared in this example), and 2 parts of flame retardant (prepared in this example); Mix thermoplastic starch, polylactic acid, sodium dodecyl sulfate, paraffin, azodicarbonamide, zinc oxide, antistatic modifier, and flame retardant for 40 min at a mixing temperature of 240 °C, cool and pulverize to obtain base material particles;

[0049] S2. Melt the base material particles and antioxidant 1010, and perform co-mixing injection molding to obtain the degradable packaging composite material. The melting injection temperature is 160 °C, and the system pressure is 6 Mpa;

[0050] The antistatic modifier is prepared by the following method:

[0051] Step A1: Disperse 1.25 g of 3-(methacryloyloxy)propyltrimethoxysilane in 50 mL of ethanol-water solution, adjust the pH to 4, stir for 2 h, then add 1.25 g of graphene oxide and 450 mL of ethanol-water solution, ultrasonically disperse evenly, react at 60 °C for 6 h, wash, filter by suction, and freeze-dry to obtain Compound 1. The volume ratio of water to ethanol in the ethanol-water solution is 1:9;

[0052] Step A2: Mix 16.3 g of p-chloromethylstyrene, 5.9 g of trimethylamine, and 0.38 g of 2,6-di-tert-butyl-4-methylphenol, heat to 70 °C and react under a nitrogen atmosphere. After heating and stirring for 3 min, continue the reaction for 24 h. Wait for the system to cool to 40 °C, wash, filter by suction, and vacuum dry at 40 °C to obtain Compound 2;

[0053] Step A3: Mix 6 g of Compound 1, 3 g of Compound 2, and 7 mL of N-vinylpyrrolidone, stir for 10 min, then add 0.45 g of azobisisobutyronitrile and 2 mL of acetonitrile and mix evenly. React in a constant temperature oil bath at 70 °C for 3 h, and perform vacuum drying at room temperature to obtain the antistatic modifier;

[0054] The flame retardant is prepared by the following method:

[0055] Step B1: Mix 200 mL of ethanol and 13.43 g of 3-aminopropyltrimethoxysilane and stir for 30 min. Then add 7.9 g of benzaldehyde and mix with 250 mL of absolute ethanol. After stirring at 80 °C for 10 h, add 0.075 mol of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and stir for 12 h. Cool to room temperature, filter, wash, and dry in vacuum at 80 °C for 6 h to obtain a pre-product;

[0056] Step B2: Mix 0.05 mol of the pre-product and 150 mL of an ethanol-water mixed solution at 35 °C for 10 min. Then add 32 mL of xylene and 6.2 g of phenylboronic acid, and continue to react at 100 °C for 5 h. After the reaction is completed, wash with water until neutral, and filter by vacuum to obtain the flame retardant. The volume ratio of ethanol to water in the ethanol-water mixed solution is 4:1.

[0057] Example 3: A preparation method of a degradable packaging composite material specifically includes the following steps:

[0058] S1. Weigh raw materials by weight parts: 85 parts of thermoplastic starch, 55 parts of polylactic acid, 10 parts of plasticizer, 6 parts of antioxidant, 12 parts of lubricant, 12 parts of foaming agent, 15 parts of foaming aid, 3 parts of antistatic modifier (prepared by this example), and 3 parts of flame retardant (prepared by this example); Mix thermoplastic starch, polylactic acid, sodium dodecyl sulfate, paraffin, azodicarbonamide, zinc oxide, antistatic modifier, and flame retardant for 50 min at a mixing temperature of 240 °C, cool and crush to obtain base material particles;

[0059] S2. Melt the base material particles and antioxidant 1010, and carry out co-mixing injection molding to obtain a degradable packaging composite material. The melting injection temperature is 160 °C, and the system pressure is 6 Mpa;

[0060] The antistatic modifier is prepared by the following method:

[0061] Step A1: Disperse 1.5 g of 3-(methacryloyloxy)propyltrimethoxysilane in 50 mL of an ethanol-water solution, adjust the pH to 4, stir for 2 h, then add 1.5 g of graphene oxide and 450 mL of an ethanol-water solution, ultrasonically disperse evenly, react at 60 °C for 6 h, wash, filter by suction, and freeze-dry to obtain Compound 1. The volume ratio of water to ethanol in the ethanol-water solution is 1:9;

[0062] Step A2: Mix 16.5 g of p-chloromethylstyrene, 6.1 g of trimethylamine, and 0.40 g of 2,6-di-tert-butyl-4-methylphenol, heat to 70 °C and react under a nitrogen atmosphere. After heating and stirring for 3 min, continue to react for 24 h. Wait for the system to cool to 40 °C, wash, filter by suction, and dry in vacuum at 40 °C to obtain Compound 2;

[0063] Step A3: Mix 7 g of Compound 1, 4 g of Compound 2 and 10 mL of N-vinylpyrrolidone, stir for 10 min, then add 0.55 g of azobisisobutyronitrile and 2 mL of acetonitrile and mix evenly. Place it in a constant temperature oil bath at 70 °C and react for 3 h. Dry it under vacuum at room temperature to obtain the antistatic modifier;

[0064] The flame retardant is prepared by the following method:

[0065] Step B1: Mix 200 mL of ethanol and 17.91 g of 3-aminopropyltrimethoxysilane and stir for 30 min. Then add 10.6 g of benzaldehyde and 250 mL of absolute ethanol and mix. Stir at 80 °C for 10 h, then add 0.1 mol of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and stir for 12 h. Cool to room temperature, filter and wash, and dry under vacuum at 80 °C for 6 h to obtain the pre-product;

[0066] Step B2: Mix 0.06 mol of the pre-product and 150 mL of an ethanol-water mixed solution at 35 °C for 10 min. Then add 45 mL of xylene and 7.4 g of phenylboronic acid and continue to react at 100 °C for 5 h. After the reaction, wash with water until neutral and filter by vacuum to obtain the flame retardant. The volume ratio of ethanol to water in the ethanol-water mixed solution is 4:1.

[0067] Comparative Example 1: This comparative example is a degradable packaging composite material. The difference from Example 3 is that an equal amount of octadecyl dimethyl hydroxyethyl ammonium nitrate is used instead of the antistatic modifier prepared in Example 3, and the rest are the same.

[0068] Comparative Example 2: This comparative example is a degradable packaging composite material. The difference from Example 3 is that an equal amount of magnesium hydroxide is used instead of the flame retardant prepared in Example 3, and the rest are the same.

[0069] Performance test: Cut the degradable packaging composite materials prepared in Examples 1-3 and Comparative Examples 1-2 into standard test sizes, test the surface resistivity according to GB / T 1410-2006, test the vertical burning performance by the plastic combustion performance test method of GB / T 2048-1996, test the tensile strength and breaking strength according to GB / T 1040.1-2006, and test the flexural strength according to GB / T 12670-2008; The test results are shown in Table 1 below:

[0070] Table 1

[0071] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Surface resistivity / Ω <![CDATA[2×10 5 > <![CDATA[2.1×10 5 > <![CDATA[2.2×10 5 > <![CDATA[2×10 6 > <![CDATA[2.3×10 5 > Vertical burning rating V-1 V-1 V-1 V-1 V-2 <![CDATA[Tensile strength / Mpa > 42 42 41 35 41 <![CDATA[Flexural strength / Mpa > 48 47 48 40 47 <![CDATA[Breaking strength / Mpa > 82 81 80 63 79

[0072] It can be seen from the data tested in Table 1 that the degradable packaging composite material prepared by the present invention has excellent antistatic and flame retardant effects. It can also be seen from the above table that the antistatic functional plastic prepared by the present invention has good tensile strength and flexural strength.

[0073] The above content is only an example and illustration of the concept of the present invention. Those skilled in the art to which the present technology pertains can make various modifications, supplements, or use similar methods for substitution to the specific embodiments described. As long as they do not deviate from the concept of the invention or exceed the scope defined by this claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a degradable packaging composite material, characterized in that: The specific steps include: S1. Weigh the raw materials by weight: 50-85 parts of thermoplastic starch, 25-55 parts of polylactic acid, 4-10 parts of plasticizer, 0.5-6 parts of antioxidant, 1-12 parts of lubricant, 4-12 parts of foaming agent, 1-15 parts of foaming aid, 1-3 parts of antistatic modifier, and 1-3 parts of flame retardant; mix the thermoplastic starch, polylactic acid, plasticizer, lubricant, foaming agent, foaming aid, antistatic modifier and flame retardant for 30-50 minutes at a mixing temperature of 240° C., cool and crush to obtain substrate particles; S2, melting the substrate particles and the antioxidant, blending and injection molding, and preparing a degradable packaging composite material, the melt injection molding temperature is 160° C., and the system pressure is 6 MPa; The antistatic modifier is prepared by the following method: Step A1: 3-(isobutylacryloyloxy)propyltrimethoxysilane was dispersed in 50 mL of ethanol-water solution, the pH was adjusted to 4, and the mixture was stirred for 2 h. Then, graphene oxide and 450 mL of ethanol-water solution were added, and the mixture was dispersed evenly by ultrasonication. The mixture was reacted at 60 ° C for 6 h, washed, filtered, and freeze-dried to obtain compound 1. Step A2: p-Chloromethylstyrene, trimethylamine and 2,6-di-tert-butyl-4-methylphenol were mixed, heated to 70°C for reaction under a nitrogen environment, heated and stirred for 3 minutes, and then the reaction was continued for 24 hours. After the system was cooled to 40°C, it was washed, filtered, and vacuum dried at 40°C to obtain compound 2; Step A3: Compound 1, compound 2 and N-vinyl pyrrolidone are mixed, stirred for 10 minutes, and then azobisisobutyronitrile and acetonitrile are added and mixed evenly, placed in a constant temperature oil bath at 70° C., reacted for 3 hours, and dried in vacuum at room temperature to obtain an antistatic modifier.

2. The method for preparing a degradable packaging composite material according to claim 1, characterized in that: In step A1, the usage ratio of 3-(isomethacryloyloxy)propyltrimethoxysilane and graphene oxide is 1.0-1.5 g:1.0-1.5 g, and the volume ratio of water to ethanol in the ethanol-water solution is 1:

9.

3. The method for preparing a degradable packaging composite material according to claim 1, characterized in that: In step A2, the mass ratio of p-chloromethylstyrene, trimethylamine and 2,6-di-tert-butyl-4-methylphenol is 16.1-16.5 g: 5.7-6.1 g: 0.36-0.40 g.

4. The method for preparing a degradable packaging composite material according to claim 1, characterized in that: In step A3, the usage ratio of compound 1, compound 2, N-vinyl pyrrolidone, azobisisobutyronitrile and acetonitrile is 5-7 g: 2-4 g: 4-10 mL: 0.35-0.55 g: 2 mL.

5. The method for preparing a degradable packaging composite material according to claim 1, characterized in that: The flame retardant is prepared by the following method: Step B1: ethanol and 3-aminopropyltrimethoxysilane were mixed and stirred for 30 minutes, then benzaldehyde and anhydrous ethanol were added and mixed, and after stirring at 80° C. for 10 hours, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was added, and stirred for 12 hours. The mixture was cooled to room temperature, filtered, washed, and vacuum dried at 80° C. for 6 hours to obtain a pre-product; Step B2: The pre-product and ethanol-water mixed solution were mixed at 35° C. for 10 min, and then xylene and phenylboric acid were added, and the reaction was continued at 100° C. for 5 h. After the reaction was completed, the mixture was washed with water until neutral, and vacuum filtered to obtain a flame retardant.

6. The method for preparing a degradable packaging composite material according to claim 5, characterized in that: In step B1, the usage ratio of ethanol, 3-aminopropyltrimethoxysilane, benzaldehyde, anhydrous ethanol, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 200 mL: 8.95-17.91 g: 5.3-10.6 g: 250 mL: 0.05-0.1 mol.

7. The method for preparing a degradable packaging composite material according to claim 5, characterized in that: In step B2, the dosage ratio of the pre-product, the ethanol-water mixed solution, the xylene and the phenylboric acid is 0.04-0.06 mol: 150 mL: 20-45 mL: 5-7.4 g; the volume ratio of ethanol to water in the ethanol-water mixed solution is 4:

1.

8. The method for preparing a degradable packaging composite material according to claim 1, characterized in that: The plasticizer is sodium lauryl sulfate, the antioxidant is antioxidant 1010, the lubricant is paraffin, the foaming agent is azodicarbonamide, and the foaming aid is zinc oxide.

9. A degradable packaging composite material, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 8.