Environment-friendly degradable plastic packaging material and preparation method thereof

Abstract

This invention relates to the field of polymer packaging materials technology, and proposes an environmentally friendly biodegradable plastic packaging material and its preparation method. The environmentally friendly biodegradable plastic packaging material comprises the following components in parts by weight: PLA 30 parts, PBAT 60-90 parts, poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) 1-5 parts, filler 20-30 parts, and stabilizer 3-5 parts. The filler includes M5 fiber and epoxy-modified silica. This technical solution solves the problem of low strength in biodegradable plastic packaging materials in related technologies.

Description

Technical Field

[0001] This invention relates to the field of polymer packaging materials technology, specifically to an environmentally friendly biodegradable plastic packaging material and its preparation method. Background Technology

[0002] With the advancement of science and technology and the increasing awareness of environmental protection, environmentally friendly packaging materials have received widespread attention. Modern packaging materials include paper, plastic, metal, and glass. Among them, plastic has become the preferred material for packaging due to its advantages such as light weight, ease of processing, and energy efficiency. However, general plastic packaging materials cause significant environmental pollution and do not conform to current environmental protection concepts. With the continuous development of materials science and technology, biodegradable plastic packaging materials have become a research hotspot.

[0003] Traditional biodegradable plastic packaging materials generally use blends of polylactic acid (PLA) and polybutylene terephthalate (PBAT), along with additives such as fillers and stabilizers. However, due to the poor compatibility between PLA and PBAT, and the difficulty in dispersing fillers in the blend and their poor compatibility with the blend itself, the strength of biodegradable plastic packaging materials is relatively low. Summary of the Invention

[0004] This invention proposes an environmentally friendly biodegradable plastic packaging material and its preparation method, which solves the problem of low strength of biodegradable plastic packaging materials in related technologies.

[0005] The technical solution of the present invention is as follows:

[0006] An environmentally friendly biodegradable plastic packaging material, the raw materials of which include the following components in parts by weight: 30 parts PLA, 60-90 parts PBAT, 1-5 parts poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate), 20-30 parts filler, and 3-5 parts stabilizer, wherein the filler includes M5 fiber and epoxy silane modified silica.

[0007] As a further technical solution, the mass ratio of the M5 fiber to the epoxy silane modified silica is 1~2:3.

[0008] In this invention, M5 fiber and epoxy silane modified silica with a mass ratio of 1~2:3 are used as fillers to further improve the strength of biodegradable plastic packaging materials.

[0009] As a further technical solution, the content of glycidyl methacrylate in the poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) is 6wt%~8wt%.

[0010] The epoxy group content in poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) is crucial to this invention. Because this invention utilizes the epoxy groups in poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) to react with PLA, PBAT, and M5 fibers, limiting the glycidyl methacrylate content in poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) to 6wt%~8wt% not only ensures sufficient reaction sites but also avoids excessive reaction sites that could trigger side reactions and affect material strength.

[0011] As a further technical solution, the raw materials for the epoxy silane modified silica include epoxy silane and silica in a mass ratio of 1~3:20.

[0012] In this invention, an epoxy-based silane and silicon dioxide in a mass ratio of 1-3:20 are used as raw materials for epoxy-based silane-modified silicon dioxide, which helps to improve the strength of biodegradable plastic packaging materials. This is because, as the amount of epoxy-based silane increases, the hydroxyl groups obtained from its hydrolysis continuously undergo condensation reactions with the hydroxyl groups on the surface of silicon dioxide, preventing silicon dioxide agglomeration. However, when the amount of epoxy-based silane is too large, the excess epoxy-based silane will partially undergo self-polymerization to form oligomers that act as bridging agents, causing agglomerates between silicon dioxide particles, affecting the dispersibility of silicon dioxide, and thus reducing the strength of the biodegradable plastic packaging material.

[0013] As a further technical solution, the average particle size of the silicon dioxide is 20~50nm.

[0014] The specific surface area of ​​silica increases as the particle size decreases. In this invention, silica with an average particle size of 20-50 nm is used. This provides abundant surface hydroxyl groups, offering sufficient reaction sites for the hydrolysis groups of epoxy-based silanes. Furthermore, it avoids excessively high surface energy of silica, which could hinder the penetration of epoxy-based silanes into the aggregates and affect the modification effect. Therefore, this invention uses silica with an average particle size of 20-50 nm as a raw material for epoxy-based silane modification, which helps improve the strength of biodegradable plastic packaging materials.

[0015] In this invention, the epoxy silane can be any conventional epoxy-containing silane in the art, such as KH-560, KH-781, KH-561, KH-1770, KH-1771 or KH-78, preferably KH-560.

[0016] As a further technical solution, the preparation method of the epoxy silane modified silica includes the following steps: dispersing silica in an aqueous ethanol solution, adding epoxy silane for modification, filtering, washing, and drying to obtain epoxy silane modified silica.

[0017] As a further technical solution, the modification temperature is 60~80℃ and the modification time is 8~10h.

[0018] In this invention, the modification temperature is limited to 60-80℃, and the modification time is limited to 8-10 hours, which helps to improve the strength of biodegradable plastic packaging materials. As the reaction proceeds, epoxy-based silanes continuously graft onto the silica surface. If the reaction time is further extended after modification, the probability of collisions between silica particles increases, leading to aggregation and reduced material strength. Furthermore, increasing the reaction temperature accelerates the hydrolysis of epoxy-based silanes and promotes the condensation reaction between epoxy-based silanes and hydroxyl groups on the silica surface. However, if the reaction temperature is too high, the Brownian motion of silica becomes too intense, exacerbating collisions between silica particles and causing aggregation, thus reducing material strength.

[0019] As a further technical solution, the stabilizer includes one or more of zinc stearate, calcium stearate, and magnesium stearate.

[0020] This invention also proposes a method for preparing an environmentally friendly biodegradable plastic packaging material, which includes the following steps: mixing raw materials evenly, extruding, granulating, and obtaining the environmentally friendly biodegradable plastic packaging material.

[0021] As a further technical solution, the following steps are included: first, PLA, PBAT, and poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) are mixed evenly, then M5 fiber is added and mixed again, and finally the remaining raw materials are added and mixed evenly, extruded, and granulated to obtain an environmentally friendly biodegradable plastic packaging material.

[0022] In the preparation process of the environmentally friendly biodegradable plastic packaging material of this invention, PLA, PBAT, and poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) are first mixed evenly, allowing the epoxy groups in the poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) to preferably react with the end groups of PLA and PBAT. Then, M5 fibers are mixed in, allowing the -NH groups in the M5 fibers to react with the residual epoxy groups. Finally, epoxy-modified silica is added, allowing the epoxy groups on the surface of the epoxy-modified silica to react with the residual -NH groups, thus attaching the epoxy-modified silica to the surface of the M5 fibers. By optimizing the order of adding each raw material, the strength of the biodegradable plastic packaging material is further improved.

[0023] The working principle and beneficial effects of this invention are as follows:

[0024] 1. In this invention, poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) is added. The epoxy groups in the poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) structure react with the end groups of PLA and PBAT, which plays a bridging role in the blend, improves the compatibility of PLA and PBAT, and thus improves the strength of the biodegradable plastic packaging material.

[0025] 2. In this invention, the addition of M5 fibers and epoxy-modified silica as fillers improves the strength of biodegradable plastic packaging materials. Because M5 fibers contain -NH groups, they can react with the epoxy groups on the surface of the epoxy-modified silica, allowing the silica to adhere to the M5 fibers and increasing their surface roughness, thereby enhancing the "interlocking" between the M5 fibers and the blend. Simultaneously, the -NH groups in the M5 fibers can also react with the epoxy groups in poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate), thus improving the compatibility between the M5 fibers and the blend. Furthermore, the epoxy-modified silica not only improves the dispersibility of silica in the blend but also enhances its compatibility with the blend through the assistance of M5 fibers and poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate). 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] The parameters of each raw material in the following examples and comparative examples are as follows:

[0028] Silica with an average particle size of 20 nm: silica content of 99.5 wt%, specific surface area of ​​180 m². 2 / g;

[0029] Silica with an average particle size of 30 nm: silica content of 99.5 wt%, specific surface area of ​​150 m². 2 / g;

[0030] Silica with an average particle size of 50 nm: silica content 99.5 wt%, specific surface area 50 m². 2 / g;

[0031] Poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate): glycidyl methacrylate content 8wt%, methyl acrylate content 25wt%;

[0032] M5 fiber: 1mm in diameter, 10μm in length;

[0033] PLA: PLA Anhui Fengyuan FY801;

[0034] PBAT: PBAT German BASF C1200.

[0035] Example 1

[0036] S1. 100 parts of silica with an average particle size of 20 nm were added to 1000 parts of an ethanol aqueous solution with a mass ratio of 3:1, ultrasonically dispersed for 15 min, 5 parts of KH-560 were added and modified at 60 °C for 10 h, filtered, washed and dried to obtain epoxy silane modified silica.

[0037] S2. First, mix 30 parts PLA, 60 parts PBAT, and 1 part poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) at 175℃ until homogeneous. Then, add 10 parts M5 fiber and continue mixing. Finally, add 10 parts epoxy silane modified silica and 3 parts zinc stearate and mix until homogeneous. Extrude and granulate to obtain an environmentally friendly biodegradable plastic packaging material.

[0038] Example 2

[0039] S1. 100 parts of silica with an average particle size of 30 nm were added to 1000 parts of an ethanol aqueous solution with a mass ratio of 3:1, ultrasonically dispersed for 20 min, 10 parts of KH-560 were added and modified at 70 °C for 9 h, filtered, washed and dried to obtain epoxy silane modified silica.

[0040] S2. First, mix 30 parts PLA, 75 parts PBAT, and 3 parts poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) at 175℃ until homogeneous. Then, add 12.5 parts M5 fiber and continue mixing. Finally, add 12.5 parts epoxy silane modified silica and 4 parts magnesium stearate and mix until homogeneous. Extrude and granulate to obtain an environmentally friendly biodegradable plastic packaging material.

[0041] Example 3

[0042] S1. 100 parts of silica with an average particle size of 50 nm were added to 1000 parts of an ethanol aqueous solution with a mass ratio of 3:1, ultrasonically dispersed for 15 min, 15 parts of KH-560 were added and modified at 80 °C for 8 h, filtered, washed and dried to obtain epoxy silane modified silica.

[0043] S2. First, mix 30 parts PLA, 90 parts PBAT, and 5 parts poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) at 175℃ until homogeneous. Then, add 15 parts M5 fiber and continue mixing. Finally, add 15 parts epoxy silane modified silica and 5 parts calcium stearate and mix until homogeneous. Extrude and granulate to obtain an environmentally friendly biodegradable plastic packaging material.

[0044] Example 4

[0045] The only difference from Example 2 is that: 10 parts of M5 fiber and 15 parts of epoxy silane modified silica.

[0046] Example 5

[0047] The only difference from Example 2 is that: 6.25 parts of M5 fiber and 18.75 parts of epoxy silane modified silica.

[0048] Example 6

[0049] The only difference from Example 2 is that: 2.5 parts of M5 fiber and 22.5 parts of epoxy silane modified silica.

[0050] Example 7

[0051] S1. 100 parts of silica with an average particle size of 30 nm were added to 1000 parts of an ethanol aqueous solution with a mass ratio of 3:1, ultrasonically dispersed for 20 min, 10 parts of KH-560 were added and modified at 70 °C for 9 h, filtered, washed and dried to obtain epoxy silane modified silica.

[0052] S2. Mix 30 parts PLA, 75 parts PBAT, 3 parts poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate), 12.5 parts M5 fiber, 12.5 parts epoxy silane modified silica, and 4 parts magnesium stearate at 175℃ until homogeneous, then extrude and granulate to obtain an environmentally friendly biodegradable plastic packaging material.

[0053] Comparative Example 1

[0054] The only difference from Example 2 is that poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) is replaced with an equal amount of KH-560.

[0055] Comparative Example 2

[0056] First, mix 30 parts PLA, 75 parts PBAT, and 3 parts poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) at 175℃ until homogeneous. Then, add 12.5 parts epoxy-silane modified silica and continue mixing. Finally, add 12.5 parts epoxy-silane modified silica and 4 parts magnesium stearate and mix until homogeneous. Extrude and granulate to obtain an environmentally friendly biodegradable plastic packaging material.

[0057] Comparative Example 3

[0058] First, mix 30 parts PLA, 75 parts PBAT, and 3 parts poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) at 175℃ until homogeneous. Then, add 12.5 parts M5 fiber and continue mixing. Finally, add 12.5 parts M5 fiber and 4 parts magnesium stearate and mix until homogeneous. Extrude and granulate to obtain an environmentally friendly biodegradable plastic packaging material.

[0059] Comparative Example 4

[0060] S1. 100 parts of silica with an average particle size of 30 nm were added to 1000 parts of an ethanol aqueous solution with a mass ratio of 3:1, ultrasonically dispersed for 20 min, 10 parts of KH-560 were added and modified at 70 °C for 9 h, filtered, washed and dried to obtain epoxy silane modified silica.

[0061] S2. First, mix 30 parts of PLA and 75 parts of PBAT at 175℃ until homogeneous. Then, add 12.5 parts of M5 fiber and continue mixing. Finally, add 12.5 parts of epoxy silane modified silica and 4 parts of magnesium stearate and mix until homogeneous. Extrude and granulate to obtain environmentally friendly biodegradable plastic packaging material.

[0062] Environmentally friendly biodegradable plastic packaging material was extruded into sheets and made into dumbbell-shaped specimens of type 1A according to GB / T 1040.2-2022. The tensile strength was then tested according to the method in GB / T 1040.1-2018 at a test speed of 50 mm / min. The test results are recorded in Table 1.

[0063] Table 1 Tensile strength test results

[0064]

[0065] As shown in Table 1, the environmentally friendly biodegradable plastic packaging material provided by this invention has a tensile strength of over 54.9 MPa, exhibiting high strength. The tensile strength of the environmentally friendly biodegradable plastic packaging materials obtained in Examples 1-7 is higher than that in Comparative Examples 1-4, indicating that the combined use of poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate), M5 fiber, and epoxy-modified silica significantly improves the strength of the environmentally friendly biodegradable plastic packaging material.

[0066] The environmentally friendly biodegradable plastic packaging material obtained in Example 2 was used as the test material. The biodegradability test was carried out according to the method in GB / T 19277.1-2011. The percentage of biodegradation was calculated, and the relative percentage of biodegradation was calculated according to the following formula. The reference material was microcrystalline cellulose, and the composting age was 3 months.

[0067] Relative biodegradation percentage = Biodegradation percentage of test material / Biodegradation percentage of reference material;

[0068] The test results are recorded in Table 2.

[0069] Table 2 Biodegradability Test Results

[0070]

[0071] As can be seen from Table 2, the plastic packaging material provided by the present invention has good biodegradability and belongs to environmentally friendly biodegradable plastic packaging material.

[0072] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An environmentally friendly, biodegradable plastic packaging material, characterized in that, The raw materials include the following components in parts by weight: 30 parts PLA, 60-90 parts PBAT, 1-5 parts poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate), 20-30 parts filler, and 3-5 parts stabilizer. The filler includes M5 fiber and epoxy silane modified silica. The preparation method includes the following steps: first, PLA, PBAT, and poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) are mixed evenly, then M5 fiber is added and mixed again, and finally the remaining raw materials are added and mixed evenly, extruded, and granulated to obtain an environmentally friendly biodegradable plastic packaging material.

2. The environmentally friendly biodegradable plastic packaging material according to claim 1, characterized in that, The mass ratio of the M5 fiber to the epoxy silane modified silica is 1~2:

3.

3. The environmentally friendly biodegradable plastic packaging material according to claim 1, characterized in that, The content of glycidyl methacrylate in the poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) is 6wt%~8wt%.

4. The environmentally friendly biodegradable plastic packaging material according to claim 1, characterized in that, The raw materials for the epoxy-silane modified silica include epoxy-silane and silica in a mass ratio of 1~3:

20.

5. The environmentally friendly biodegradable plastic packaging material according to claim 4, characterized in that, The average particle size of the silica is 20~50nm.

6. The environmentally friendly biodegradable plastic packaging material according to claim 4, characterized in that, The preparation method of the epoxy silane modified silica includes the following steps: dispersing silica in an aqueous ethanol solution, adding epoxy silane for modification, filtering, washing, and drying to obtain epoxy silane modified silica.

7. The environmentally friendly biodegradable plastic packaging material according to claim 6, characterized in that, The modification temperature is 60~80℃, and the modification time is 8~10h.

8. The environmentally friendly biodegradable plastic packaging material according to claim 1, characterized in that, The stabilizer includes one or more of zinc stearate, calcium stearate, and magnesium stearate.

9. A method for preparing an environmentally friendly biodegradable plastic packaging material according to any one of claims 1 to 8, characterized in that, Includes the following steps: First, PLA, PBAT, and poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) are mixed evenly. Then, M5 fiber is added and mixed again. Finally, the remaining raw materials are added and mixed evenly. The mixture is then extruded and granulated to obtain an environmentally friendly biodegradable plastic packaging material.

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