Preparation method of degradable high-barrier composite BOPP matting film

Abstract

The present invention discloses a degradable high-barrier composite BOPP matting film. The present invention also discloses a preparation method of the above-mentioned degradable high-barrier composite BOPP matting film. Tannic acid is added to a single-layer magnesium-aluminum hydrotalcite colloid, the system is adjusted to be alkaline, and stirring is continued for 1-3 h. Then it is mixed uniformly with polypropylene and added to an extruder, and melt-extruded at 180-200 °C to obtain a composite polypropylene resin. The composite polypropylene resin, polyhydroxybutyrate, polylactic acid, and cross-linking agent are blended and cast into a base film blank with a thickness of 0.1-1 mm. The matting agent and the slip agent are mixed uniformly, melt-extruded and formed, and then added to the base film blank to obtain a matting blank. The matting blank is biaxially stretched at 80-90 °C, the stretching speed is 40-70 mm / s, the stretching ratio is 4-10, and the stretched blank is irradiated with an electron beam in a nitrogen atmosphere to obtain the degradable high-barrier composite BOPP matting film.

Description

Technical Field

[0001] The invention relates to the technical field of BOPP matt films, and in particular to a degradable high-barrier composite BOPP matt film and a preparation method thereof. Background Art

[0002] The purpose of food packaging is to ensure that the food does not deteriorate irreversibly before it is purchased by consumers. With the continuous innovation of material science and packaging technology, packaging materials are also constantly developing to meet the needs of consumers. At present, in the market economy, consumers' requirements for packaging materials include natural, safe, low price, extended shelf life, and ready to eat.

[0003] Nanocomposite packaging materials are new packaging materials made of nanoparticles and other packaging materials. At present, there are many nanocomposite packaging materials on the market, such as PE / nano-Ag, PP / TiO2, PA / nano-montmorillonite powder, etc., and they have begun to be used on a large scale in the food packaging industry, achieving good packaging effects. The introduction of nanotechnology in the field of food packaging has greatly solved the problems of food quality, safety and stability. Food packaging based on nanomaterials has better barrier properties, mechanical properties and food preservation capabilities. Therefore, nanocomposite packaging materials have strong development momentum and broad application prospects.

[0004] Hydrotalcite materials are anionic layered compounds. Layered compounds refer to a class of compounds with layered structures, interlayer ions, and exchangeability. By utilizing the intercalation and interlayer ion exchangeability of the layered compound body under the action of strong polar molecules, some functional guest substances are introduced into the interlayer gaps and the distance between the layers is expanded to form layered column compounds. A typical hydrotalcite compound is magnesium aluminum carbonate type hydrotalcite: Mg6Al2(OH) 16 CO3·4H2O, the structure is very similar to brucite [Mg(OH)2], which is formed by the shared edges of MgO6 octahedrons to form a unit layer. 2+ Can be Al within a certain range 3+ Isomorphous substitution makes the layers positively charged and there is exchangeable CO3 between the layers 2- Balanced with the positive charge on the layer plates, the overall structure of LDHs is electrically neutral.

[0005] At present, adding nanocrystalline magnesium aluminum carbonate type hydrotalcite into BOPP matte film to improve the barrier properties of BOPP matte film not only has limited improvement in barrier properties, but also has a certain negative impact on the mechanical properties of BOPP matte film. This is because there are compatibility issues between nanocrystalline magnesium aluminum carbonate type hydrotalcite and polypropylene resin, which needs to be solved urgently. Summary of the invention

[0006] The object of the present invention is to solve the disadvantages existing in the prior art, and to provide a degradable high-barrier composite BOPP matting film and a preparation method thereof.

[0007] A preparation method of a degradable high-barrier composite BOPP matting film comprises the following steps:

[0008] S1. Add tannic acid to a single-layer magnesium-aluminum hydrotalcite colloid, adjust the system to be alkaline, continue stirring for 1-3 h, mix evenly with polypropylene, and then add it to an extruder, and melt and extrude at 180-200 °C to obtain a composite polypropylene resin;

[0009] S2. Blend the composite polypropylene resin, polyhydroxybutyrate, polylactic acid, and crosslinking agent, and cast and form to obtain a base film blank with a thickness of 0.1-1 mm; after uniformly mixing the matting agent and the slip agent, melt and extrude and then form, and then add the base film blank to mix to obtain a matting blank;

[0010] S3. Biaxially stretch the matting blank at 80-90 °C, with a stretching speed of 40-70 mm / s and a stretching ratio of 4-10, and irradiate the stretched blank with an electron beam in a nitrogen atmosphere, with an irradiation dose of 50-100 kGy, to obtain a degradable high-barrier composite BOPP matting film.

[0011] Preferably, in S1, the mass ratio of the single-layer magnesium-aluminum hydrotalcite colloid, tannic acid, and polypropylene is 20-40:1-2:50-100.

[0012] Preferably, in S1, the single-layer magnesium-aluminum hydrotalcite colloid is obtained by interchanging carbonate ions in nano-magnesium-aluminum carbonate hydrotalcite with nitrate ions, causing the hydrotalcite structure to delaminate, and forming a single-layer magnesium-aluminum hydrotalcite colloid under the action of formamide.

[0013] Preferably, in S1, the single-layer magnesium-aluminum hydrotalcite colloid is prepared by the following specific steps: under nitrogen protection, heat deionized water to 100 °C, add nano-magnesium-aluminum carbonate hydrotalcite and stir evenly, add nitric acid and sodium nitrate and stir for 20-30 h, cool to room temperature, centrifuge, wash, dry, grind, add to formamide, and stir under nitrogen protection for 10-20 h to obtain a single-layer magnesium-aluminum hydrotalcite colloid.

[0014] Preferably, in S1, the mass ratio of nano-magnesium-aluminum carbonate hydrotalcite, nitric acid, sodium nitrate, and formamide is 5-15:1-2:0.1-0.5:15-25.

[0015] Preferably, in S1, the centrifugation speed is 5000-6000 r / min.

[0016] Preferably, in S1, the centrifuged product is washed successively with water and acetone.

[0017] Preferably, in S2, the mass ratio of the composite polypropylene resin, polyhydroxybutyrate, polylactic acid, crosslinking agent, matting agent, and slip agent is 50-100:10-20:5-15:1-2:10-20:1-2.

[0018] Preferably, in S2, the crosslinking agent is at least one of triallyl isocyanurate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, and triallyl cyanurate.

[0019] A degradable high-barrier composite BOPP matting film is prepared by using the preparation method of the above-mentioned degradable high-barrier composite BOPP matting film.

[0020] The technical effects of the present invention are as follows:

[0021] Since it is difficult for magnesium-aluminum carbonate-type hydrotalcite to combine with polypropylene, in the composite polypropylene resin, nitric acid and sodium nitrate are compounded, and carbonate ions in nano magnesium-aluminum hydrotalcite are exchanged by nitrate ions between layers, promoting the delamination of nano magnesium-aluminum carbonate-type hydrotalcite, and then forming a single-layer magnesium-aluminum hydrotalcite colloid under the action of formamide.

[0022] In the present invention, tannic acid can act as both a hydrogen bond donor and a hydrogen bond acceptor. On the one hand, the alkaline environment can inhibit the self-association of tannic acid, and on the other hand, it can form hydrogen bond sites in the single-layer magnesium-aluminum hydrotalcite colloid, and then be melt-extruded with polypropylene, with high mutual dispersion uniformity. At the same time, after being modified by tannic acid, tannic acid can act as a bridge, and the three form a hydrogen bond network; then it is compounded with polyhydroxybutyrate and polylactic acid. Due to the good two-dimensional order of the hydrotalcite nanosheets, and the high degree of uniform dispersion and high directionality between the organic polymer matrix, after biaxial stretching, its barrier performance is extremely excellent. However, at a draw ratio of 4-10, the formed film is extremely prone to crack defect structures, resulting in a significant decrease in the barrier ability of the stretched film.

[0023] The present invention further adopts irradiation treatment to promote the formation of a three-dimensional polymer network of polyhydroxybutyrate, polylactic acid and the crosslinking agent, and cooperate with biaxial stretching and irradiation to promote the degradation of highly cross-linked macromolecular chains. The combined action can effectively promote the recovery of cracks, and can effectively improve its impact resistance on the basis of ensuring the tensile strength of the product, and the mechanical properties of the product are excellent. Description of the Drawings

[0024] Figure 1 It is a comparison chart of the tensile strength and barrier performance of the degradable high-barrier composite BOPP matting films obtained in Example 5 and Comparative Examples 1-2. Detailed Embodiments

[0025] The present invention will be further explained below in conjunction with specific embodiments.

[0026] Example 1

[0027] A preparation method of a degradable high-barrier composite BOPP matting film, comprising the following steps:

[0028] S1. Add 1 kg of tannic acid to 20 kg of single-layer magnesium-aluminum hydrotalcite colloid, adjust the system to be alkaline, continue stirring for 1 h, mix evenly with 50 kg of polypropylene, then add it to an extruder, and melt-extrude at 180 °C to obtain a composite polypropylene resin;

[0029] The single-layer magnesium-aluminum hydrotalcite colloid is prepared by the following specific steps: Heat 50 kg of deionized water to 100 °C under nitrogen protection, add 5 kg of nano-magnesium-aluminum carbonate-type hydrotalcite and stir evenly, add 1 kg of nitric acid and 0.1 kg of sodium nitrate, stir for 20 h, cool to room temperature, centrifuge at a centrifugal speed of 5000 r / min, wash successively with water and acetone, dry, grind, add it to 15 kg of formamide, and stir for 10 h under nitrogen protection at a stirring speed of 50 r / min to obtain a single-layer magnesium-aluminum hydrotalcite colloid;

[0030] S2. Blend 50 kg of composite polypropylene resin, 10 kg of polyhydroxybutyrate, 5 kg of polylactic acid, and 1 kg of triallyl isocyanurate, and obtain a base film blank with a thickness of 0.1 mm through casting molding; After mixing 10 kg of matting agent and 1 kg of slip agent evenly, melt-extrude and mold them, and then add them to the base film blank to obtain a matting blank;

[0031] S3. Biaxially stretch the matting blank at 80 °C at a stretching speed of 40 mm / s and a stretching ratio of 4, and irradiate the stretched blank with an electron beam in a nitrogen atmosphere with an irradiation dose of 50 kGy to obtain a degradable high-barrier composite BOPP matting film.

[0032] Example 2

[0033] A preparation method of a degradable high-barrier composite BOPP matting film, comprising the following steps:

[0034] S1. Add 2 kg of tannic acid to 40 kg of single-layer magnesium-aluminum hydrotalcite colloid, adjust the system to be alkaline, continue stirring for 3 h, mix evenly with 100 kg of polypropylene, then add it to an extruder, and melt-extrude at 200 °C to obtain a composite polypropylene resin;

[0035] The single-layer magnesium-aluminum hydrotalcite colloid is prepared by the following specific steps: Under nitrogen protection, 100 kg of deionized water is heated to 100 °C, 15 kg of nano magnesium-aluminum carbonate-type hydrotalcite is added and stirred evenly, 2 kg of nitric acid and 0.5 kg of sodium nitrate are added and stirred for 30 h, cooled to room temperature, centrifuged at a centrifugal speed of 6000 r / min, washed successively with water and acetone, dried, ground, added to 25 kg of formamide, and stirred under nitrogen protection for 20 h at a stirring speed of 100 r / min to obtain the single-layer magnesium-aluminum hydrotalcite colloid;

[0036] S2. Blend 100 kg of composite polypropylene resin, 20 kg of polyhydroxybutyrate, 15 kg of polylactic acid, and 2 kg of triallyl cyanurate, and obtain a base film blank with a thickness of 1 mm through casting; Mix 20 kg of matting agent and 2 kg of slip agent evenly, melt and extrude them, and then add them to the base film blank to mix and obtain a matting blank;

[0037] S3. Biaxially stretch the matting blank at 90 °C at a stretching speed of 70 mm / s and a stretching ratio of 10, and irradiate the stretched blank with electron beam in a nitrogen atmosphere with an irradiation dose of 100 kGy to obtain the degradable high-barrier composite BOPP matting film.

[0038] Example 3

[0039] A preparation method of a degradable high-barrier composite BOPP matting film includes the following steps:

[0040] S1. Add 1.7 kg of tannic acid to 25 kg of single-layer magnesium-aluminum hydrotalcite colloid, adjust the system to be alkaline, continue stirring for 1.5 h, mix evenly with 80 kg of polypropylene, and then add it to an extruder to melt and extrude at 185 °C to obtain a composite polypropylene resin;

[0041] The single-layer magnesium-aluminum hydrotalcite colloid is prepared by the following specific steps: Under nitrogen protection, 80 kg of deionized water is heated to 100 °C, 8 kg of nano magnesium-aluminum carbonate-type hydrotalcite is added and stirred evenly, 1.7 kg of nitric acid and 0.2 kg of sodium nitrate are added and stirred for 28 h, cooled to room temperature, centrifuged at a centrifugal speed of 5200 r / min, washed successively with water and acetone, dried, ground, added to 22 kg of formamide, and stirred under nitrogen protection for 12 h at a stirring speed of 90 r / min to obtain the single-layer magnesium-aluminum hydrotalcite colloid;

[0042] S2. Blend 70 kg of composite polypropylene resin, 17 kg of polyhydroxybutyrate, 8 kg of polylactic acid, and 1.7 kg of trimethylolpropane triacrylate, and obtain a base film blank with a thickness of 0.3 mm through casting; Mix 17 kg of matting agent and 1.2 kg of slip agent evenly, melt and extrude them, and then add them to the base film blank to mix and obtain a matting blank;

[0043] S3. Biaxially stretch the matting blank at 88 °C with a stretching speed of 50 mm / s and a stretching ratio of 8. Irradiate the stretched blank with an electron beam in a nitrogen atmosphere with an irradiation dose of 70 kGy to obtain a degradable high-barrier composite BOPP matting film.

[0044] Example 4

[0045] A preparation method of a degradable high-barrier composite BOPP matting film includes the following steps:

[0046] S1. Add 1.3 kg of tannic acid to 35 kg of single-layer magnesium-aluminum hydrotalcite colloid, adjust the system to be alkaline, continue stirring for 2.5 h, mix evenly with 60 kg of polypropylene, and then add it to an extruder to melt and extrude at 195 °C to obtain a composite polypropylene resin;

[0047] The single-layer magnesium-aluminum hydrotalcite colloid is prepared by the following specific steps: Heat 60 kg of deionized water to 100 °C under nitrogen protection, add 12 kg of nano magnesium-aluminum carbonate-type hydrotalcite and stir evenly, add 1.3 kg of nitric acid and 0.4 kg of sodium nitrate and stir for 22 h, cool to room temperature, centrifuge at a speed of 5800 r / min, wash successively with water and acetone, dry, grind, add it to 18 kg of formamide, and stir for 18 h under nitrogen protection at a stirring speed of 70 r / min to obtain a single-layer magnesium-aluminum hydrotalcite colloid;

[0048] S2. Blend 90 kg of composite polypropylene resin, 13 kg of polyhydroxybutyrate, 12 kg of polylactic acid, and 1.3 kg of trimethylolpropane trimethacrylate, and perform casting molding to obtain a base film blank with a thickness of 0.6 mm; Mix 13 kg of matting agent and 1.8 kg of slip agent evenly, melt and extrude them, and then add them to the base film blank to mix and obtain a matting blank;

[0049] S3. Biaxially stretch the matting blank at 82 °C with a stretching speed of 60 mm / s and a stretching ratio of 6. Irradiate the stretched blank with an electron beam in a nitrogen atmosphere with an irradiation dose of 90 kGy to obtain a degradable high-barrier composite BOPP matting film.

[0050] Example 5

[0051] A preparation method of a degradable high-barrier composite BOPP matting film includes the following steps:

[0052] S1. Add 1.5 kg of tannic acid to 30 kg of single-layer magnesium-aluminum hydrotalcite colloid, adjust the system to be alkaline, continue stirring for 2 h, mix evenly with 70 kg of polypropylene, and then add it to an extruder to melt and extrude at 190 °C to obtain a composite polypropylene resin;

[0053] The monolithic magnesium-aluminum hydrotalcite colloid is prepared by the following specific steps: Under nitrogen protection, heat 70 kg of deionized water to 100 °C, add 10 kg of nano magnesium-aluminum carbonate-type hydrotalcite and stir evenly, add 1.5 kg of nitric acid and 0.3 kg of sodium nitrate, stir for 25 h, cool to room temperature, centrifuge at a speed of 5500 r / min, wash successively with water and acetone, dry, grind, add to 20 kg of formamide, and stir for 15 h under nitrogen protection at a stirring speed of 80 r / min to obtain the monolithic magnesium-aluminum hydrotalcite colloid;

[0054] S2. Blend 80 kg of composite polypropylene resin, 15 kg of polyhydroxybutyrate, 10 kg of polylactic acid, and 1.5 kg of trimethylolpropane triacrylate, and obtain a base film blank with a thickness of 0.5 mm through casting molding; Mix 15 kg of matting agent and 1.5 kg of slip agent evenly, melt and extrude them into a mold, and then add them to the base film blank and mix to obtain a matting blank;

[0055] S3. Biaxially stretch the matting blank at 85 °C at a stretching speed of 55 mm / s and a stretching ratio of 7, and irradiate the stretched blank with an electron beam in a nitrogen atmosphere with an irradiation dose of 80 kGy to obtain a degradable high-barrier composite BOPP matting film.

[0056] Comparative Example 1

[0057] A preparation method of a degradable high-barrier composite BOPP matting film includes the following steps:

[0058] S1. Add 1.5 kg of tannic acid to 30 kg of monolithic magnesium-aluminum hydrotalcite colloid, adjust the system to be alkaline, continue stirring for 2 h, mix evenly with 70 kg of polypropylene, and then add it to an extruder and melt-extrude at 190 °C to obtain a composite polypropylene resin;

[0059] The monolithic magnesium-aluminum hydrotalcite colloid is prepared by the following specific steps: Under nitrogen protection, heat 70 kg of deionized water to 100 °C, add 10 kg of nano magnesium-aluminum carbonate-type hydrotalcite and stir evenly, add 1.5 kg of nitric acid and 0.3 kg of sodium nitrate, stir for 25 h, cool to room temperature, centrifuge at a speed of 5500 r / min, wash successively with water and acetone, dry, grind, add to 20 kg of formamide, and stir for 15 h under nitrogen protection at a stirring speed of 80 r / min to obtain the monolithic magnesium-aluminum hydrotalcite colloid;

[0060] S2. Blend 80 kg of composite polypropylene resin, 15 kg of polyhydroxybutyrate, 10 kg of polylactic acid, and 1.5 kg of trimethylolpropane triacrylate, and obtain a base film blank with a thickness of 0.5 mm through casting molding; Mix 15 kg of matting agent and 1.5 kg of slip agent evenly, melt and extrude them into a mold, and then add them to the base film blank and mix to obtain a matting blank;

[0061] S3. Biaxially stretch the matting blank at 85 °C with a stretching speed of 55 mm / s and a stretching ratio of 7 to obtain a degradable high-barrier composite BOPP matting film.

[0062] Comparative Example 2

[0063] A method for preparing a degradable high-barrier composite BOPP matting film includes the following steps:

[0064] S1. Add 70 kg of polypropylene to 30 kg of nano magnesium-aluminum hydrotalcite and mix evenly, then add it to an extruder and melt-extrude at 190 °C to obtain a composite polypropylene resin;

[0065] S2. Blend 80 kg of the composite polypropylene resin, 15 kg of polyhydroxybutyrate, 10 kg of polylactic acid, and 1.5 kg of trimethylolpropane triacrylate, and perform cast molding to obtain a base film blank with a thickness of 0.5 mm; Mix 15 kg of matting material and 1.5 kg of slip agent evenly, then melt-extrude and mold, and then add it to the base film blank to obtain a matting blank;

[0066] S3. Biaxially stretch the matting blank at 85 °C with a stretching speed of 55 mm / s and a stretching ratio of 7, and irradiate the stretched blank with electron beams in a nitrogen atmosphere with an irradiation dose of 80 kGy to obtain a degradable high-barrier composite BOPP matting film.

[0067] Perform a comparative experiment on the degradable high-barrier composite BOPP matting films obtained in Example 5 and Comparative Examples 1-2, as follows:

[0068] According to GB / T 16928-1997 Test Methods for Packaging Materials - Moisture Vapor Transmission Rate, use a W3 / 60 type water vapor transmission rate test system to test the moisture vapor transmission coefficient of each group. According to GB / T1040.3-2006 Plastics - Determination of Tensile Properties - Part 3: Test Conditions for Films and Strips, use a tensile rate of 50 mm / min to test the longitudinal / transverse tensile strength of each group.

[0069] The results are as Figure 1 shown. The longitudinal / transverse tensile strength of the degradable high-barrier composite BOPP matting film obtained in Example 5 is far superior to that of the comparative examples, while the moisture vapor transmission rate is lower than that of the comparative examples, indicating that the barrier performance of the degradable high-barrier composite BOPP matting film obtained in Example 5 is superior to that of the comparative examples.

[0070] It is found through the comparison between Comparative Example 2 and Example 5 that both use a single-layer magnesium-aluminum hydrotalcite colloid modified by tannic acid, melt-extruded with polypropylene, and then compounded with polyhydroxybutyrate and polylactic acid. Due to the good two-dimensional order of the hydrotalcite nanosheets, and the high degree of uniform dispersion and high directionality between the organic polymer matrix, after biaxial stretching, its barrier performance is extremely excellent.

[0071] However, for Comparative Example 2, when the draw ratio is 4-10, the obtained film is extremely prone to crack defect structures, resulting in a significant decrease in the barrier ability of the film after stretching. In Example 5, irradiation treatment is adopted to promote the formation of a three-dimensional polymer network of polyhydroxybutyrate, polylactic acid and a cross-linking agent, and the combination of biaxial stretching and irradiation promotes the degradation of highly cross-linked macromolecular chains. The combined action can effectively promote the recovery of cracks, effectively improve its impact resistance while ensuring the tensile strength of the product, and the mechanical properties of the product are excellent.

[0072] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A preparation method of a degradable high-barrier composite BOPP matting film, characterized in that, It includes the following steps: S1. Add tannic acid to the single-layer magnesium-aluminum hydrotalcite colloid, adjust the system to be alkaline, continue stirring for 1 - 3 h, mix evenly with polypropylene, and then add it to an extruder to melt and extrude at 180 - 200 °C to obtain a composite polypropylene resin; S2. Blend the composite polypropylene resin, polyhydroxybutyrate, polylactic acid, and cross-linking agent, and cast and form to obtain a base film blank with a thickness of 0.1 - 1 mm; Mix the matting agent and slip agent evenly, melt and extrude them and then form, and then add the base film blank to mix to obtain a matting blank; S3. Biaxially stretch the matting blank at 80 - 90 °C, with a stretching speed of 40 - 70 mm / s and a stretching ratio of 4 - 10, and irradiate the stretched blank with an electron beam in a nitrogen atmosphere, with an irradiation dose of 50 - 100 kGy, to obtain a degradable high-barrier composite BOPP matting film.

2. The preparation method of the degradable high-barrier composite BOPP matting film according to claim 1, wherein In S1, the mass ratio of the single-layer magnesium-aluminum hydrotalcite colloid, tannic acid, and polypropylene is 20 - 40:1 - 2:50 - 100.

3. The preparation method of the degradable high-barrier composite BOPP matting film according to claim 1, characterized in that, In S1, the single-layer magnesium-aluminum hydrotalcite colloid is obtained by interchanging carbonate ions in nano-magnesium-aluminum carbonate hydrotalcite with nitrate ions to cause the hydrotalcite structure to delaminate and form a single-layer magnesium-aluminum hydrotalcite colloid under the action of formamide.

4. The preparation method of the degradable high-barrier composite BOPP matting film according to claim 3, characterized in that, In S1, the single-layer magnesium-aluminum hydrotalcite colloid is prepared by the following specific steps: Under nitrogen protection, heat deionized water to 100 °C, add nano-magnesium-aluminum carbonate hydrotalcite and stir evenly, add nitric acid and sodium nitrate and stir for 20 - 30 h, cool to room temperature, centrifuge, wash, dry, grind, add it to formamide, and stir for 10 - 20 h under nitrogen protection to obtain a single-layer magnesium-aluminum hydrotalcite colloid.

5. The preparation method of the degradable high-barrier composite BOPP matte film according to claim 4, characterized in that, In S1, the mass ratio of nano-magnesium-aluminum carbonate hydrotalcite, nitric acid, sodium nitrate, and formamide is 5 - 15:1 - 2:0.1 - 0.5:15 - 25.

6. The preparation method of the degradable high-barrier composite BOPP matte film according to claim 4, wherein, In S1, the centrifugation speed is 5000 - 6000 r / min.

7. The preparation method of the degradable high-barrier composite BOPP matte film according to claim 4, characterized in that, In S1, the centrifuged product is washed successively with water and acetone.

8. The preparation method of the degradable high-barrier composite BOPP matting film according to claim 1, characterized in that, In S2, the mass ratio of the composite polypropylene resin, polyhydroxybutyrate, polylactic acid, cross-linking agent, matting agent, and slip agent is 50 - 100:10 - 20:5 - 15:1 - 2:10 - 20:1 - 2.

9. The preparation method of the degradable high-barrier composite BOPP matte film according to claim 1, characterized in that, In S2, the cross-linking agent is at least one of triallyl isocyanurate, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, and triallyl cyanurate.

10. A degradable high-barrier composite BOPP matte film, characterized in that, It is prepared by the preparation method of the degradable high-barrier composite BOPP matting film according to any one of claims 1 - 9.

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