Production process of biodegradable film material

Abstract

A biodegradable film material production process belongs to the field of biodegradable films, and comprises the following steps: step 1, obtaining a top layer material in a molten state; 2, the molten top layer material obtained in the step 1 is fed into a film blowing machine to be subjected to film manufacturing operation, and a top layer film is obtained; 3, obtaining an inner layer material in a molten state; 4, the molten inner layer material obtained in the step 3 is fed into a film blowing machine to be subjected to film manufacturing operation, and an inner layer film is obtained; 5, a bottom layer material in a molten state is obtained; sixthly, the bottom layer material in the molten state obtained in the fifth step is fed into a film blowing machine to be subjected to film manufacturing operation, and a bottom layer film is obtained; and 7, performing hot pressing on the top layer film, the inner layer film and the bottom layer film to obtain the biodegradable film. The top layer film and the bottom layer film are respectively arranged above and below the inner layer film, so that the strength of the biodegradable film is ensured, and meanwhile, the growth of crops can be promoted after degradation, so that the condition that the performance of the biodegradable film is reduced due to the addition of substances for promoting the growth of the crops is solved.

Description

Technical Field

[0001] The invention belongs to the field of biodegradable films, in particular to a production process of biodegradable film materials. Background Art

[0002] Biodegradable film refers to a type of plastic film that can be decomposed by microorganisms in the natural environment. At the end of its lifespan, this film is decomposed by microorganisms in soil and water, or by ultraviolet rays from sunlight, returning to the natural environment and reducing environmental pollution.

[0003] Most of the current biodegradable films are obtained by directly mixing and melting all the raw materials to form a film. Since biodegradable films are mostly used for crop growth, substances that can promote crop growth are added to the biodegradable films to promote crop growth. After the biodegradable films are degraded, they are applied to the soil to promote crop growth. However, the addition of these substances that promote crop growth will affect the performance of the biodegradable films, thereby affecting their use effect. Summary of the Invention

[0004] The present invention provides a production process of a biodegradable film material, which is used to solve the defects in the prior art.

[0005] The present invention is achieved through the following technical solutions:

[0006] A biodegradable film material production process comprises the following steps:

[0007] Step 1: Add polypropylene carbonate, polybutylene succinate, and polyhydroxyvalerate into a reaction kettle and heat to melt, then add a crosslinking agent, an antioxidant, and a plasticizer, mix well, and then add an inorganic filler and stir well to obtain a molten top layer material;

[0008] Step 2: feeding the molten top layer material obtained in step 1 into a film blowing machine for film forming operation to obtain a top layer film;

[0009] Step 3: Add polyethylene and polypropylene into a reactor and heat to melt, then add corn cross-linked starch and mix evenly, then add hydroxyethyl cellulose, vitamin B, humic acid, epoxidized soybean oil and ferrocene and stir evenly to obtain a molten inner layer material;

[0010] Step 4: feeding the molten inner layer material obtained in step 3 into a film blowing machine for film forming operation to obtain an inner layer film;

[0011] Step 5: Add poly (3-hydroxybutyrate), polyethylene succinate, and polycaprolactone into a reaction kettle and heat to melt, then add a cross-linking agent, an antioxidant, and a plasticizer, mix well, and then add an inorganic filler and stir well to obtain a molten base material;

[0012] Step 6: feeding the molten bottom layer material obtained in step 5 into a film blowing machine for film forming operation to obtain a bottom layer film;

[0013] Step 7: The top layer film, the inner layer film and the bottom layer film are pressed in a hot press in a top-down order to obtain a biodegradable film.

[0014] In the above-mentioned process for producing a biodegradable film material, the mass proportions of the substances in step 1 are: 60-80 parts of polypropylene carbonate; 60-70 parts of polybutylene succinate; 70-80 parts of polyhydroxyvalerate; 1-3 parts of a cross-linking agent; 1-2 parts of an antioxidant; 2-3 parts of a plasticizer; and 15-25 parts of an inorganic filler.

[0015] According to the above-mentioned process for producing a biodegradable film material, the propylene carbonate, polybutylene succinate, and polyhydroxyvalerate in the step 1 are added to a reactor and heated to melt at a temperature of 175-185°C. After melting, a cross-linking agent, an antioxidant, and a plasticizer are added and mixed at a temperature of 160-170°C and a speed of 80-100 r / min for 15-25 minutes. Subsequently, an inorganic filler is added and mixed at a temperature of 160-170°C and a speed of 120-150 r / min for 10-15 minutes.

[0016] In the above-mentioned process for producing a biodegradable film material, the mass proportions of the substances in step three are: 40-60 parts of polyethylene; 40-50 parts of polypropylene; 20-30 parts of corn cross-linked starch; 10-20 parts of hydroxyethyl cellulose; 3-5 parts of vitamin B3; 10-20 parts of humic acid; 6-10 parts of epoxidized soybean oil; and 3-5 parts of ferrocene.

[0017] The above-mentioned process for producing a biodegradable film material comprises the following steps: in step 3, polyethylene and polypropylene are added to a reactor and heated to melt at a temperature of 170-180°C; after melting, cross-linked corn starch is added and mixed at a temperature of 165-175°C and a speed of 100-120 r / min for 15-20 minutes; and then hydroxyethyl cellulose, vitamin B, humic acid, epoxidized soybean oil and ferrocene are added and mixed at a temperature of 155-165°C and a speed of 170-200 r / min for 8-10 minutes.

[0018] In the above-mentioned process for producing a biodegradable film material, the mass fractions of the substances in step five are: 70-80 parts of poly (3-hydroxybutyrate); 50-60 parts of polyethylene succinate; 40-60 parts of polycaprolactone; 1-2 parts of a cross-linking agent; 1-2 parts of an antioxidant; 1-2 parts of a plasticizer; and 20-24 parts of an inorganic filler.

[0019] According to the above-mentioned process for producing a biodegradable film material, in the step 5, poly (3-hydroxybutyrate), polyethylene succinate, and polycaprolactone are added to a reactor and heated to a melting temperature of 170-180°C. After melting, a cross-linking agent, an antioxidant, and a plasticizer are added and mixed at a temperature of 150-160°C and a speed of 100-120 r / min for 15-20 minutes. Subsequently, an inorganic filler is added and mixed at a temperature of 150-160°C and a speed of 130-150 r / min for 10-14 minutes.

[0020] The above-mentioned process for producing a biodegradable film material, wherein the molecular weight of the polypropylene carbonate is 60,000-80,000;

[0021] A biodegradable film material production process as described above, wherein the molecular weight of the polyethylene is 600,000-800,000;

[0022] A biodegradable film material production process as described above, wherein the molecular weight of the polypropylene is 200,000-400,000;

[0023] A biodegradable film material production process as described above, wherein the molecular weight of the polycaprolactone is 100,000-130,000;

[0024] A biodegradable film material production process as described above, wherein the cross-linking agent is 1,4-butanediol diglycidyl ether;

[0025] A biodegradable film material production process as described above, wherein the antioxidant is tris(2,4-di-tert-butylphenyl)phosphite;

[0026] A biodegradable film material production process as described above, wherein the plasticizer is acetyl tributyl citrate;

[0027] In the above-mentioned process for producing a biodegradable film material, the inorganic filler is nano-scale calcium carbonate.

[0028] The above-mentioned process for producing a biodegradable film material, wherein the cross-linked corn starch is nano-scale cross-linked corn starch;

[0029] The hydroxyethyl cellulose described in the above-mentioned process for producing a biodegradable film material is nano-grade hydroxyethyl cellulose;

[0030] The vitamin B in the above-mentioned biodegradable film material production process is nano-scale vitamin B;

[0031] The humic acid described in the above-mentioned process for producing a biodegradable film material is nano-scale humic acid;

[0032] The ferrocene described in the above-mentioned process for producing a biodegradable film material is nano-sized ferrocene.

[0033] In the above-mentioned biodegradable film material production process, in step seven, the thickness of the top film is 0.1 mm, the thickness of the inner film is 0.2 mm, the thickness of the bottom film is 0.1 mm, the operating temperature of the hot press is 160-170°C, and the operating pressure of the hot press is 1.6-1.8 MPa.

[0034] The advantages of the present invention are as follows: the present invention prepares an inner layer film by combining corn cross-linked starch, hydroxyethyl cellulose, vitamin B, humic acid, epoxidized soybean oil and ferrocene, which can serve as both degradable materials and substances that promote crop growth, with polyethylene and polypropylene, and then arranges a top film and a bottom film above and below the inner layer film, respectively, to ensure the strength of the biodegradable film while promoting crop growth after degradation, thereby solving the problem of reducing the performance of the biodegradable film due to the addition of substances that promote crop growth; in the present invention, the ferrocene in the inner layer material can also be used as a photosensitizer, which can accelerate the decomposition rate of the inner layer film after the top film and the bottom film are decomposed, thereby ensuring that the corn cross-linked starch, hydroxyethyl cellulose, vitamin B, humic acid, epoxidized soybean oil and ferrocene are quickly decomposed and released into the soil, thereby promoting crop growth. DETAILED DESCRIPTION

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with 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 making creative efforts shall fall within the scope of protection of the present invention.

[0036] Example 1

[0037] Step 1: Weigh the materials according to the following ratio: 60 parts of polypropylene carbonate (molecular weight of 60,000-80,000); 60 parts of polybutylene succinate; 70 parts of polyhydroxyvalerate; 1 part of 1,4-butanediol diglycidyl ether; 1 part of tris(2,4-di-tert-butylphenyl) phosphite; add propylene carbonate, polybutylene succinate, and polyhydroxyvalerate into a reactor and heat to melt at a temperature of 175°C, and after melting, add 1,4-butanediol diglycidyl ether, tris(2,4-di-tert-butylphenyl) phosphite and acetyl tributyl citrate and mix at a temperature of 160°C and a speed of 80r / min for 25min, then add nano-calcium carbonate and mix at a temperature of 160°C and a speed of 120r / min for 15min to obtain a molten top layer material;

[0038] Step 2: feeding the molten top layer material obtained in step 1 into a film blowing machine for film forming operation to obtain a top layer film with a thickness of 0.1 mm;

[0039] Step 3: Weigh the materials according to the following ratio: 40 parts of polyethylene (molecular weight 600,000-800,000); 40 parts of polypropylene (molecular weight 200,000-400,000); 20 parts of corn cross-linked starch; 10 parts of hydroxyethyl cellulose; 3 parts of vitamin B; 10 parts of humic acid; 6 parts of epoxidized soybean oil; 3 parts of ferrocene; add polyethylene and polypropylene into a reactor and heat to melt at a temperature of 170°C, add corn cross-linked starch after melting, and mix at a temperature of 165°C and a speed of 100 r / min for 20 minutes, then add hydroxyethyl cellulose, vitamin B, humic acid, epoxidized soybean oil and ferrocene and mix at a temperature of 155°C and a speed of 170 r / min for 10 minutes to obtain a molten inner layer material;

[0040] Step 4: feeding the molten inner layer material obtained in step 3 into a film blowing machine for film forming operation to obtain an inner layer film with a thickness of 0.2 mm;

[0041] Step 5: Weigh the materials according to the following ratio: 70 parts of poly 3-hydroxybutyrate; 50 parts of polyethylene succinate; 40 parts of polycaprolactone (molecular weight 100,000-130,000); 1 part of 1,4-butanediol diglycidyl ether; 1 part of tris (2,4-di-tert-butylphenyl) phosphite; 1 part of acetyl tributyl citrate; 20 parts of nano-calcium carbonate; add poly 3-hydroxybutyrate, polyethylene succinate, and polycaprolactone into a reactor and heat to a melting temperature of 170°C. After melting, add 1,4-butanediol diglycidyl ether, tris (2,4-di-tert-butylphenyl) phosphite and acetyl tributyl citrate and mix at a temperature of 150°C and a speed of 100 r / min for 20 minutes, then add nano-calcium carbonate and mix at a temperature of 150°C and a speed of 130 r / min for 14 minutes, then add nano-calcium carbonate and stir evenly to obtain a molten bottom material;

[0042] Step 6: feeding the molten base material obtained in step 5 into a film blowing machine for film forming operation to obtain a base film with a thickness of 0.1 mm;

[0043] Step 7: The top film, the inner film and the bottom film are put through a hot press in a top-down order (the operating temperature of the hot press is 160° C. and the operating pressure of the hot press is 1.6 MPa) to obtain a biodegradable film.

[0044] Example 2

[0045] Step 1: Weigh the materials according to the following ratio: 80 parts of polypropylene carbonate (molecular weight of 60,000-80,000); 70 parts of polybutylene succinate; 80 parts of polyhydroxyvalerate; 3 parts of 1,4-butanediol diglycidyl ether; 2 parts of tris(2,4-di-tert-butylphenyl) phosphite; add propylene carbonate, polybutylene succinate, and polyhydroxyvalerate into a reactor and heat to melt at a temperature of 175-185° C., after melting, add 1,4-butanediol diglycidyl ether, tris(2,4-di-tert-butylphenyl) phosphite and acetyl tributyl citrate, mix at a temperature of 170° C. and a speed of 100 r / min for 15 minutes, then add nano-calcium carbonate, mix at a temperature of 170° C. and a speed of 150 r / min for 10 minutes to obtain a molten top layer material;

[0046] Step 2: feeding the molten top layer material obtained in step 1 into a film blowing machine for film forming operation to obtain a top layer film with a thickness of 0.1 mm;

[0047] Step 3: Weigh the materials according to the following ratio: 60 parts of polyethylene (molecular weight 600,000-800,000); 50 parts of polypropylene (molecular weight 200,000-400,000); 30 parts of corn cross-linked starch; 20 parts of hydroxyethyl cellulose; 5 parts of vitamin B; 20 parts of humic acid; 10 parts of epoxidized soybean oil; 5 parts of ferrocene; add polyethylene and polypropylene into a reactor and heat to melt at a temperature of 180°C, add corn cross-linked starch after melting, and mix at a temperature of 175°C and a speed of 120r / min for 15 minutes, then add hydroxyethyl cellulose, vitamin B, humic acid, epoxidized soybean oil and ferrocene and mix at a temperature of 165°C and a speed of 200r / min for 8 minutes to obtain a molten inner layer material;

[0048] Step 4: feeding the molten inner layer material obtained in step 3 into a film blowing machine for film forming operation to obtain an inner layer film with a thickness of 0.2 mm;

[0049] Step 5: Weigh the materials according to the following ratio: 80 parts of poly 3-hydroxybutyrate; 60 parts of polyethylene succinate; 60 parts of polycaprolactone (molecular weight 100,000-130,000); 2 parts of 1,4-butanediol diglycidyl ether; 2 parts of tris(2,4-di-tert-butylphenyl) phosphite; 2 parts of acetyl tributyl citrate; 24 parts of nano-calcium carbonate; add poly 3-hydroxybutyrate, polyethylene succinate, and polycaprolactone into a reactor and heat to a melting temperature of 180°C. After melting, add 1,4-butanediol diglycidyl ether, tris(2,4-di-tert-butylphenyl) phosphite and acetyl tributyl citrate and mix at a temperature of 160°C and a speed of 120r / min for 15min, then add nano-calcium carbonate and mix at a temperature of 160°C and a speed of 150r / min for 10min, then add nano-calcium carbonate and stir evenly to obtain a molten bottom material;

[0050] Step 6: feeding the molten base material obtained in step 5 into a film blowing machine for film forming operation to obtain a base film with a thickness of 0.1 mm;

[0051] Step 7: The top film, the inner film and the bottom film are put through a hot press in a top-down order (the operating temperature of the hot press is 170° C. and the operating pressure of the hot press is 1.8 MPa) to obtain a biodegradable film.

[0052] Example 3

[0053] Step 1: Weigh the materials according to the following ratio: 70 parts of polypropylene carbonate (molecular weight of 60,000-80,000); 65 parts of polybutylene succinate; 75 parts of polyhydroxyvalerate; 2 parts of 1,4-butanediol diglycidyl ether; 1.5 parts of tris(2,4-di-tert-butylphenyl) phosphite; add propylene carbonate, polybutylene succinate, and polyhydroxyvalerate into a reactor and heat to melt at a temperature of 175-185° C., after melting, add 1,4-butanediol diglycidyl ether, tris(2,4-di-tert-butylphenyl) phosphite and acetyl tributyl citrate, mix at a temperature of 165° C. and a speed of 90 r / min for 20 minutes, then add nano-calcium carbonate, mix at a temperature of 165° C. and a speed of 135 r / min for 13 minutes to obtain a molten top layer material;

[0054] Step 2: feeding the molten top layer material obtained in step 1 into a film blowing machine for film forming operation to obtain a top layer film with a thickness of 0.1 mm;

[0055] Step 3: Weigh the materials according to the following ratio: 50 parts of polyethylene (molecular weight 600,000-800,000); 45 parts of polypropylene (molecular weight 200,000-400,000); 25 parts of corn cross-linked starch; 15 parts of hydroxyethyl cellulose; 4 parts of vitamin B; 15 parts of humic acid; 8 parts of epoxidized soybean oil; 4 parts of ferrocene; add polyethylene and polypropylene into a reactor and heat to melt at a temperature of 175°C, add corn cross-linked starch after melting, and mix at a temperature of 170°C and a speed of 110 r / min for 18 minutes, then add hydroxyethyl cellulose, vitamin B, humic acid, epoxidized soybean oil and ferrocene, and mix at a temperature of 160°C and a speed of 185 r / min for 9 minutes to obtain a molten inner layer material;

[0056] Step 4: feeding the molten inner layer material obtained in step 3 into a film blowing machine for film forming operation to obtain an inner layer film with a thickness of 0.2 mm;

[0057] Step 5: Weigh the materials according to the following ratio: 75 parts of poly 3-hydroxybutyrate; 55 parts of polyethylene succinate; 50 parts of polycaprolactone (molecular weight 100,000-130,000); 1.5 parts of 1,4-butanediol diglycidyl ether; 1.5 parts of tris(2,4-di-tert-butylphenyl) phosphite; 1.5 parts of acetyl tributyl citrate; 22 parts of nano-calcium carbonate; add poly 3-hydroxybutyrate, polyethylene succinate, and polycaprolactone into a reactor and heat to a melting temperature of 175°C. After melting, add 1,4-butanediol diglycidyl ether, tris(2,4-di-tert-butylphenyl) phosphite and acetyl tributyl citrate and mix at a temperature of 155°C and a speed of 110r / min for 17min, then add nano-calcium carbonate and mix at a temperature of 155°C and a speed of 140r / min for 12min, then add nano-calcium carbonate and stir evenly to obtain a molten bottom material;

[0058] Step 6: feeding the molten base material obtained in step 5 into a film blowing machine for film forming operation to obtain a base film with a thickness of 0.1 mm;

[0059] Step 7: The top film, the inner film and the bottom film are put through a hot press in a top-down order (the operating temperature of the hot press is 165° C. and the operating pressure of the hot press is 1.7 MPa) to obtain a biodegradable film.

[0060] Comparative Example 1

[0061] Step 1: Weigh the following materials according to the following ratio: 40 parts of polyethylene (molecular weight 600,000-800,000); 40 parts of polypropylene (molecular weight 200,000-400,000); 20 parts of cross-linked corn starch; 10 parts of hydroxyethyl cellulose; 3 parts of vitamin B; 10 parts of humic acid; 6 parts of epoxidized soybean oil; 3 parts of ferrocene;

[0062] Step 2: adding polyethylene and polypropylene into a reactor and heating them to a melting temperature of 170° C., adding corn cross-linked starch after melting, mixing at a temperature of 165° C. and a rotation speed of 100 r / min for 20 minutes, then adding hydroxyethyl cellulose, vitamin B, humic acid, epoxidized soybean oil and ferrocene, mixing at a temperature of 155° C. and a rotation speed of 170 r / min for 10 minutes to obtain a molten material;

[0063] Step 3: The molten material obtained in step 2 is fed into a film blowing machine for film forming operation to obtain a biodegradable film with a thickness of 0.4 mm.

[0064] Comparative Example 2

[0065] Step 1: Weigh the following materials according to the following ratio: 60 parts of polyethylene (molecular weight 600,000-800,000); 50 parts of polypropylene (molecular weight 200,000-400,000); 30 parts of cross-linked corn starch; 20 parts of hydroxyethyl cellulose; 5 parts of vitamin B; 20 parts of humic acid; 10 parts of epoxidized soybean oil; 5 parts of ferrocene;

[0066] Step 2: Polyethylene and polypropylene are added to a reactor and heated to a melting temperature of 180° C. After melting, corn cross-linked starch is added and mixed at a temperature of 175° C. and a rotation speed of 120 r / min for 15 minutes. Subsequently, hydroxyethyl cellulose, vitamin B, humic acid, epoxidized soybean oil and ferrocene are added and mixed at a temperature of 165° C. and a rotation speed of 200 r / min for 8 minutes to obtain a molten material;

[0067] Step 3: The molten material obtained in step 2 is fed into a film blowing machine for film forming operation to obtain a biodegradable film with a thickness of 0.4 mm.

[0068] Comparative Example 3

[0069] Step 1: Weigh the following materials according to the following ratio: 50 parts of polyethylene (molecular weight 600,000-800,000); 45 parts of polypropylene (molecular weight 200,000-400,000); 25 parts of cross-linked corn starch; 15 parts of hydroxyethyl cellulose; 4 parts of vitamin B; 15 parts of humic acid; 8 parts of epoxidized soybean oil; 4 parts of ferrocene;

[0070] Step 2: Polyethylene and polypropylene are added to a reactor and heated to a melting temperature of 175° C. After melting, corn cross-linked starch is added and mixed at a temperature of 170° C. and a rotation speed of 110 r / min for 18 minutes. Subsequently, hydroxyethyl cellulose, vitamin B, humic acid, epoxidized soybean oil and ferrocene are added and mixed at a temperature of 160° C. and a rotation speed of 185 r / min for 9 minutes to obtain a molten material;

[0071] Step 3: The molten material obtained in step 2 is fed into a film blowing machine for film forming operation to obtain a biodegradable film with a thickness of 0.4 mm.

[0072] The biodegradable films prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests, wherein the tensile strength and elongation at break were tested using the method of GB / T 1040-2006, and the tear strength was tested using the method of GB / T 16578-2023. The test results are shown in Table 1.

[0073] Group Tensile strength (MPa) Elongation at break (%) Tear strength (N / mm) Example 1 38.9 453.3 189.3 Example 2 37.8 457.9 186.4 Example 3 41.6 472.3 195.6 Comparative Example 1 22.6 302.8 134.2 Comparative Example 2 21.5 314.7 136.8 Comparative Example 3 22.9 325.4 143.6

[0074] Table 1

[0075] As can be seen from the data in Table 1, the tensile strength, elongation at break, and tear strength of the biodegradable films prepared in Examples 1-3 of the present invention are far superior to those in Comparative Examples 1-3. Therefore, the biodegradable films prepared in the present invention can release corn cross-linked starch, hydroxyethyl cellulose, vitamin B, humic acid, epoxidized soybean oil, and ferrocene, which are substances that can promote crop growth, while ensuring the performance of the biodegradable films. This ensures the performance of the biodegradable films while promoting crop growth.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A process for producing a biodegradable film material, characterized by: The steps include: Step 1: Add polypropylene carbonate, polybutylene succinate, and polyhydroxyvalerate into a reaction kettle and heat to melt, then add a crosslinking agent, an antioxidant, and a plasticizer, mix well, and then add an inorganic filler and stir well to obtain a molten top layer material; Step 2: feeding the molten top layer material obtained in step 1 into a film blowing machine for film forming operation to obtain a top layer film; Step 3: Add polyethylene and polypropylene into a reactor and heat to melt, then add corn cross-linked starch and mix evenly, then add hydroxyethyl cellulose, vitamin B, humic acid, epoxidized soybean oil and ferrocene and stir evenly to obtain a molten inner layer material; Step 4: feeding the molten inner layer material obtained in step 3 into a film blowing machine for film forming operation to obtain an inner layer film; Step 5: Add poly (3-hydroxybutyrate), polyethylene succinate, and polycaprolactone into a reaction kettle and heat to melt, then add a cross-linking agent, an antioxidant, and a plasticizer, mix well, and then add an inorganic filler and stir well to obtain a molten base material; Step 6: feeding the molten bottom layer material obtained in step 5 into a film blowing machine for film forming operation to obtain a bottom layer film; Step 7: The top layer film, the inner layer film and the bottom layer film are pressed in a hot press in a top-down order to obtain a biodegradable film.

2. The process for producing a biodegradable film material according to claim 1, wherein: The mass proportions of the substances in step 1 are: 60-80 parts of polypropylene carbonate; 60-70 parts of polybutylene succinate; 70-80 parts of polyhydroxyvalerate; 1-3 parts of a crosslinking agent; 1-2 parts of an antioxidant; 2-3 parts of a plasticizer; and 15-25 parts of an inorganic filler.

3. The process for producing a biodegradable film material according to claim 1, wherein: The propylene carbonate, polybutylene succinate, and polyhydroxyvalerate in the step 1 are added to a reactor and heated to melt at a temperature of 175-185° C. After melting, a crosslinking agent, an antioxidant, and a plasticizer are added and mixed at a temperature of 160-170° C. and a speed of 80-100 r / min for 15-25 minutes. Subsequently, an inorganic filler is added and mixed at a temperature of 160-170° C. and a speed of 120-150 r / min for 10-15 minutes.

4. The process for producing a biodegradable film material according to claim 1, wherein: The mass proportions of the substances in step 3 are: 40-60 parts of polyethylene; 40-50 parts of polypropylene; 20-30 parts of corn cross-linked starch; 10-20 parts of hydroxyethyl cellulose; 3-5 parts of vitamin B3; 10-20 parts of humic acid; 6-10 parts of epoxidized soybean oil; and 3-5 parts of ferrocene.

5. The process for producing a biodegradable film material according to claim 1, wherein: In the step 3, polyethylene and polypropylene are added to the reactor and heated to melt at a temperature of 170-180°C. After melting, corn cross-linked starch is added and mixed at a temperature of 165-175°C and a speed of 100-120 r / min for 15-20 minutes. Subsequently, hydroxyethyl cellulose, vitamin B, humic acid, epoxidized soybean oil and ferrocene are added and mixed at a temperature of 155-165°C and a speed of 170-200 r / min for 8-10 minutes.

6. The process for producing a biodegradable film material according to claim 1, wherein: The mass fractions of the substances in the step 5 are: 70-80 parts of poly 3-hydroxybutyrate; 50-60 parts of polyethylene succinate; 40-60 parts of polycaprolactone; 1-2 parts of a crosslinking agent; 1-2 parts of an antioxidant; 1-2 parts of a plasticizer; and 20-24 parts of an inorganic filler.

7. The process for producing a biodegradable film material according to claim 1, wherein: In the step 5, poly 3-hydroxybutyrate, polyethylene succinate, and polycaprolactone are added to a reactor and heated to a melting temperature of 170-180°C. After melting, a crosslinker, an antioxidant, and a plasticizer are added and mixed at a temperature of 150-160°C and a speed of 100-120 r / min for 15-20 minutes. Subsequently, an inorganic filler is added and mixed at a temperature of 150-160°C and a speed of 130-150 r / min for 10-14 minutes.

8. The process for producing a biodegradable film material according to claim 1, wherein: The molecular weight of the polypropylene carbonate is 60,000-80,000; The molecular weight of the polyethylene is 600,000-800,000; The molecular weight of the polypropylene is 200,000-400,000; The molecular weight of the polycaprolactone is 100,000-130,000; The cross-linking agent is 1,4-butanediol diglycidyl ether; The antioxidant is tris(2,4-di-tert-butylphenyl)phosphite; The plasticizer is acetyl tributyl citrate; The inorganic filler is nano-scale calcium carbonate.

9. The process for producing a biodegradable film material according to claim 1, wherein: The cross-linked corn starch is nano-scale cross-linked corn starch; The hydroxyethyl cellulose is nano-grade hydroxyethyl cellulose; The vitamin B is nano-scale vitamin B; The humic acid is nano-scale humic acid; The ferrocene is nano-sized ferrocene.

10. The process for producing a biodegradable film material according to claim 1, wherein: In the step seven, the thickness of the top film is 0.1 mm, the thickness of the inner film is 0.2 mm, and the thickness of the bottom film is 0.1 mm. The operating temperature of the hot press is 160-170° C., and the operating pressure of the hot press is 1.6-1.8 MPa.