A Degradable Bicolor Plastic Film Material and Its Preparation Method

Abstract

This application relates to the technical field of degradable films, and specifically discloses a degradable two-color plastic film material and a preparation method thereof. A degradable two-color plastic film material, one side of the plastic film is silver, and the other side of the plastic film is black. The plastic film comprises the following materials in mass percentages: 60-65% of PBAT; 5-10% of PLA; 10-20% of PPC; 5-10% of additives. The preparation method is as follows: PPC is dried to obtain dried PPC, the dried PPC, PLA, PBAT and additives are blended, extruded and pelletized, the extrusion temperature is 180-190 °C, and blow molding is carried out to obtain the plastic film. The plastic film of this application can be used in the planting of fruit and vegetable products and crops, and has the advantages of being fully biodegradable, improving the coloring effect of crops, and excellent mechanical properties; in addition, the preparation method of this application has the advantage of simple operation.

Description

Technical Field

[0001] The present application relates to the technical field of ground films, and more specifically, to a degradable two-color ground film material and a preparation method thereof. Background Art

[0002] Ground film is used for ground covering to increase soil temperature, retain soil moisture, maintain soil structure, prevent pests from attacking crops and diseases caused by certain microorganisms, etc., and promote plant growth.

[0003] The main material of ordinary mulch film usually contains high molecular weight polyethylene compounds and resins, which are not easy to rot and extremely difficult to decompose. Not only does the mulch film need to be recycled, but the residual film will also affect the soil fertility, causing poor water and nutrient migration in the soil, aggravating the harm to crop growth, and the recycling of residual film is also more likely to cause harm to the environment. Therefore, improving the degradable properties of mulch film, maintaining soil fertility, and improving crop growth is an urgent problem to be solved. Summary of the invention

[0004] In order to improve the degradability of ground film and the growth effect of crops, the present application provides a degradable two-color ground film material and a preparation method thereof.

[0005] The present application provides a degradable two-color ground film material, which adopts the following technical solution:

[0006] In a first aspect, the present application provides a degradable two-color ground film material, one side of the ground film is silver, and the other side of the ground film is black, and the ground film comprises the following materials in the following mass percentages:

[0007] PBAT 60-65%;

[0008] PLA 5-10%;

[0009] PPC 10-20%;

[0010] Additives 5-10%.

[0011] By adopting the above technical solution, firstly, since PBAT, PLA and PPC are all degradable materials, the above materials can be blended to prepare ground film, so that a biodegradable ground film can be obtained, and there is no need to recycle the ground film, which not only reduces the production cost, but also the residual film is not easy to have adverse effects on the soil.

[0012] Secondly, PBAT is a typical biodegradable aliphatic / aromatic copolyester with excellent toughness, elongation at break and heat resistance. Therefore, using PBAT as the main material for the mulch film can endow the mulch film with excellent mechanical strength and heat resistance. PLA is polylactic acid, a linear plastic microbial-degradable polyester obtained by dehydration condensation of lactic acid molecules with hydroxyl and carboxyl groups, with better strength, transparency, thermal stability and processability. Adding PLA to the mulch film can further improve the mechanical strength of the mulch film. PPC is poly(propylene carbonate), i.e., a copolymer of titanium dioxide and propylene oxide, an amorphous polymer with good film-forming property and excellent gas barrier property. Preparing the mulch film by blending PBAT, PLA and PPC can effectively improve the thermal stability of PPC and obtain a mulch film with excellent film-forming property and mechanical properties.

[0013] Finally, one side of the mulch film in this application is black, and the black side is used for weed suppression, which can inhibit weeds by blocking their photosynthesis. The other side of the mulch film is silver, and the silver side is used for covering crops. Through the reflective effect of silver, it can increase the coloring effect of crops and improve the growth effect of crops.

[0014] Optionally, the mulch film further comprises 5-10% by mass of collagen, which is extracted from waste leather.

[0015] By adopting the above technical solution, this application preferably adds collagen to the mulch film. Collagen contains many amino acids, and the amino acids contain polar groups such as hydroxyl, carboxyl, amino and other groups, which can crosslink and combine with the other components in the mulch film, improve the crosslinking degree of the mulch film and enhance the mechanical properties of the mulch film. And collagen is a biodegradable material, which can decompose together with the mulch film material. Moreover, due to the high nitrogen content of collagen, it can be converted into soil nitrogen fertilizer during the degradation process, supplementing nutrients for crops and soil and saving the cost of fertilization. This application extracts collagen from waste leather, which can reuse waste leather and reduce environmental pollution caused by waste, combining economic benefits and environmental benefits.

[0016] Optionally, the collagen is collagen modified by a modifier, and the modifier includes glycidyl methacrylate.

[0017] By adopting the above technical solution, glycidyl methacrylate is used to modify collagen. Glycidyl methacrylate has carbon-carbon double bonds, epoxy groups and relatively long carbon chains. The carbon-carbon double bonds are more likely to undergo free radical reactions, and then react with active sites such as active hydroxyl groups, carboxyl groups, amino groups and mercapto groups in collagen to achieve grafting. As a result, glycidyl methacrylate can be grafted onto collagen, and a long carbon chain structure and epoxy groups can be grafted onto collagen, which can effectively improve the hydrophobicity and heat resistance of collagen, thus making up for the hydrophobic loss and heat resistance loss brought by collagen in the ground film, and endowing the ground film with excellent water-proof, heat-insulating and mechanical properties.

[0018] In addition, glycidyl methacrylate can also react with the terminal carboxyl groups of other components in the ground film such as PBAT, improve the molecular weight and thermal stability of PBAT, and can effectively improve the compatibility between collagen and other components in the ground film, further improving the structural stability and mechanical strength of the ground film.

[0019] Optionally, the preparation method of the modified collagen is as follows: Take collagen, sodium sulfite and urea solution, mix and stir to obtain a collagen solution; Add glycidyl methacrylate and ammonium persulfate to the collagen solution, keep the temperature for reaction, wash and centrifuge to retain the solid, wash with alcohol, filter by suction, and dry to obtain the modified collagen.

[0020] By adopting the above technical solution, the modification steps of collagen are optimized. Under the initiation of ammonium persulfate, the double bond of glycidyl methacrylate is opened and combined with the active sites on collagen to achieve grafting on collagen.

[0021] Optionally, the mass ratio of the collagen to the glycidyl methacrylate is 1-2:1, and the reaction temperature is 70-90 °C.

[0022] By adopting the above technical solution, the mass ratio between collagen and glycidyl methacrylate is optimized. An appropriate mass ratio can enable glycidyl methacrylate to be fully grafted onto collagen, reduce the homopolymerization of glycidyl methacrylate, and improve the grafting efficiency. The reaction temperature in the grafting reaction is optimized. An appropriate temperature can generate more free radicals and grafting sites, and improve the diffusion and grafting of collagen and glycidyl methacrylate.

[0023] Optionally, the modifier also includes ethanol.

[0024] By adopting the above technical solution, ethanol is used to modify collagen. The alcohol hydroxyl group can carry out an esterification reaction with the carboxyl group on the side chain of the collagen molecule, effectively extending the molecular chain of collagen, promoting the construction of a cross-linked network of collagen, reducing the hydrophilic groups in collagen, improving the binding effect between collagen and the other components in the plastic film, and improving the hydrophobicity of the plastic film.

[0025] Optionally, the PBAT is PBAT modified with maleic anhydride.

[0026] By adopting the above technical solution, maleic anhydride forms a polar side chain with the polymer molecular chain through a single ring, is not prone to homopolymerization, can carry out a graft reaction with PBAT through free radicals, and undergoes chain growth, chain transfer and chain termination reactions to obtain modified PBAT, which can fully improve the compatibility of PBAT. After the anhydride group in maleic anhydride is ring-opened, it can form a carboxyl group and combine with the active groups in collagen, improving the binding effect between collagen and the other components in the plastic film, enabling collagen and PBAT to enhance the interfacial force through chemical bonding, and improving the mechanical strength of the plastic film.

[0027] Optionally, the preparation of the modified PBAT is as follows: PBAT and xylene are mixed and heated in an oil bath to obtain a mixed solution. Maleic anhydride and an initiator are added to the mixed solution, and the reaction is continued. Then it is poured into an acetone solution, vacuum filtered, and repeatedly purified, washed and dried to obtain the modified PBAT.

[0028] In a second aspect, the present application provides a preparation method for a degradable two-color plastic film material, adopting the following technical solution:

[0029] A preparation method for a degradable two-color plastic film material is as follows: PPC is dried to obtain dried PPC. The dried PPC, PLA, PBAT and additives are blended, extruded and granulated. The extrusion temperature is 180-190 °C, and then blow molding is carried out to obtain a composite film. Silver paint and black paint are coated on both sides of the composite film and dried to obtain the plastic film.

[0030] Optionally, the blow-molded composite film is placed in glutaraldehyde vapor to obtain the plastic film.

[0031] By adopting the above technical solution, when the blow-molded product is placed in glutaraldehyde vapor, first, the aldehyde group in glutaraldehyde can react with the primary amine group in the material to form a Schiff base structure, thereby promoting cross-linking between the components in the plastic film, further improving the compactness of the plastic film, and further improving the hydrophobicity, barrier property and mechanical property of the plastic film.

[0032] In summary, the present application has the following beneficial effects:

[0033] 1. In this application, since PBAT, PLA, and PPC are all biodegradable materials, using the above materials to blend and prepare a mulch film can obtain a biodegradable mulch film, eliminating the need for recycling the mulch film. This not only reduces production costs but also prevents the residual film from having an adverse impact on the soil. By blending PBAT, PLA, and PPC to prepare the mulch film, the thermal stability of PPC can be effectively improved, and a mulch film with excellent film-forming properties and mechanical properties can be obtained. One side of the mulch film is black, and the black side is used for suppressing weeds by blocking the photosynthesis of weeds. The other side of the mulch film is silver, and the silver side is used for covering crops. Through the reflective effect of silver, the coloring effect of crops can be increased, and the growth effect of crops can be improved.

[0034] 2. This application preferably adds collagen to the mulch film. Collagen contains many amino acids, and the amino acids contain polar groups such as hydroxyl, carboxyl, and amino groups, which can cross-link and combine with the other components in the mulch film to increase the cross-linking degree of the mulch film and improve its mechanical properties. Moreover, collagen is a biodegradable material and can decompose together with the mulch film material. Since collagen has a high nitrogen content, it can be converted into soil nitrogen fertilizer during the degradation process, supplementing nutrients to crops and the soil and saving the cost of fertilization. By extracting collagen from waste leather in this application, the waste leather can be reused, reducing environmental pollution caused by waste, and having both economic and environmental benefits.

[0035] 3. In this application, glycidyl methacrylate is used to modify collagen. Glycidyl methacrylate has a carbon-carbon double bond, an epoxy group, and a long carbon chain. Glycidyl methacrylate can be grafted onto collagen, enabling long carbon chain structures and epoxy groups to be grafted onto collagen, effectively improving the hydrophobicity and heat resistance of collagen, thus compensating for the hydrophobic and heat resistance losses brought by collagen in the mulch film and endowing the mulch film with excellent water resistance, heat insulation, and mechanical properties. Moreover, by reacting glycidyl methacrylate with the terminal carboxyl groups of PBAT, the molecular weight and thermal stability of PBAT are increased, and the compatibility between collagen and the other components in the mulch film can be effectively improved, further enhancing the structural stability and mechanical strength of the mulch film. Detailed implementation mode

[0036] The following further elaborates on this application in combination with examples.

[0037] Preparation example

[0038] Collagen preparation example

[0039] Preparation example 1

[0040] The waste leather is crushed to obtain waste leather powder. The waste leather powder is impregnated in concentrated sulfuric acid. The mass percentage of concentrated sulfuric acid to waste leather powder is 8%, the liquid-solid ratio is 10, the hydrolysis temperature is 70 °C, and it is soaked for 12 h. Stir once every 3 hours during the acid leaching process to obtain an extract. The extract is filtered, centrifuged, neutralized, concentrated, neutralized, concentrated, and freeze-dried to obtain a powdery collagen hydrolyzate. The powdery collagen hydrolyzate is purified (using TFEA and water as co-solvents, glycerol as a plasticizer, and dialysis treatment is carried out using a dialysis bag with a cut-off relative molecular mass of 3500 Da) to obtain collagen powder.

[0041] Preparation Example of Modified Collagen

[0042] Preparation Example 2

[0043] 20 g of the collagen powder prepared in Preparation Example 1, 3.5 g of sodium sulfite, and 400 mL of urea solution (3.33 mol / L) are magnetically stirred at 50 °C for 30 min to obtain a collagen solution;

[0044] 10 g of glycidyl methacrylate and 225 g of ammonium persulfate are added to the collagen solution, and the reaction is carried out at 70 °C for 4 h while maintaining the temperature. Wash with acetone, centrifuge to retain the solid, repeat twice, wash twice with ethanol, filter by suction, and dry to obtain modified collagen.

[0045] Preparation Example 3

[0046] 20 g of the collagen powder prepared in Preparation Example 1, 3.5 g of sodium sulfite, and 400 mL of urea solution (3.33 mol / L) are magnetically stirred at 50 °C for 30 min to obtain a collagen solution;

[0047] 15 g of glycidyl methacrylate and 225 g of ammonium persulfate are added to the collagen solution, and the reaction is carried out at 80 °C for 4 h while maintaining the temperature. Wash with acetone, centrifuge to retain the solid, repeat twice, wash twice with ethanol, filter by suction, and dry to obtain modified collagen.

[0048] Preparation Example 4

[0049] 20 g of the collagen powder prepared in Preparation Example 1, 3.5 g of sodium sulfite, and 400 mL of urea solution (3.33 mol / L) are magnetically stirred at 50 °C for 30 min to obtain a collagen solution; 20 g of glycidyl methacrylate and 225 g of ammonium persulfate are added to the collagen solution, and the reaction is carried out at 80 °C for 4 h while maintaining the temperature. Wash with acetone, centrifuge to retain the solid, repeat twice, wash twice with ethanol, filter by suction, and dry to obtain modified collagen.

[0050] Preparation Example 5

[0051] Mix 20 g of the collagen powder prepared in Preparation Example 1 with water to obtain a collagen solution with a mass fraction of 20%. Add 20 mL of absolute ethanol to the collagen solution, continuously react at 55 °C, centrifuge, retain the solid matter, and dry to obtain modified collagen.

[0052] Preparation Example of Modified PBAT

[0053] Preparation Example 6

[0054] Mix 20 g of PBAT with 200 mL of xylene, heat in an oil bath to 95 °C to dissolve PBAT to obtain a mixed solution. Add 6 g of maleic anhydride and 0.6 g of benzoyl peroxide (BPO) to the mixed solution, continuously react for 4 h, pour it into an acetone solution, perform vacuum filtration, repeat purification, washing, and drying to obtain modified PBAT.

[0055] Preparation Example 7

[0056] Mix 20 g of PBAT with 200 mL of xylene, heat in an oil bath to 95 °C to dissolve PBAT to obtain a mixed solution. Add 4.5 g of maleic anhydride, 1.5 g of glycidyl methacrylate, and 0.6 g of benzoyl peroxide (BPO) to the mixed solution, continuously react for 4 h, pour it into an acetone solution, perform vacuum filtration, repeat purification, washing, and drying to obtain modified PBAT.

[0057] Examples

[0058] Examples 1 - 3

[0059] On the one hand, the present application provides a degradable two - color plastic film material. One side of the plastic film is formed as black, and the other side is formed as silver. The silver side is used for reflecting light to improve the coloring effect of crops, and the black side is used for suppressing weed growth by pressing weeds and absorbing light sources. The plastic film comprises the following raw materials: PBAT, PPC, PLA, and additives. The specific masses are shown in the following table.

[0060] Among them, the additives include an antioxidant, a light stabilizer, and a lubricant with a mass ratio of 2:3:5. The antioxidant is antioxidant 1010, the light stabilizer is light stabilizer 119, and the lubricant is zinc stearate.

[0061] On the other hand, the present application provides a preparation method of a degradable two - color plastic film material, which comprises the following steps: Place PPC at 60 °C for drying treatment to obtain dried PPC. Blend the dried PPC, PLA, PBAT, and additives, extrude and pelletize. The extrusion temperature is 180 °C, and blow - mold to form a composite film. Coat silver paint and black paint on both sides of the composite film, and dry to obtain the plastic film.

[0062] Table 1 Composition of Plastic Films in Examples 1 - 3

[0063] Mass percentage / % Example 1 Example 2 Example 3 PBAT 60 62 65 PPC 10 8 5 PLA 20 15 15 Auxiliary agent 10 8 5

[0064] Example 4

[0065] The difference from Example 3 is that the plastic film also includes 10% by mass of the collagen prepared in Preparation Example 1 to prepare the plastic film.

[0066] Example 5

[0067] The difference from Example 4 is that an equal mass of the modified collagen prepared in Preparation Example 2 is used to replace the collagen in Example 4 to prepare the plastic film.

[0068] Example 6

[0069] The difference from Example 4 is that an equal mass of the modified collagen prepared in Preparation Example 3 is used to replace the collagen in Example 4 to prepare the plastic film.

[0070] Example 7

[0071] The difference from Example 4 is that an equal mass of the modified collagen prepared in Preparation Example 4 is used to replace the collagen in Example 4 to prepare the plastic film.

[0072] Example 8

[0073] The difference from Example 4 is that an equal mass of the modified collagen prepared in Preparation Example 5 is used to replace the collagen in Example 4 to prepare the plastic film.

[0074] Example 9

[0075] The difference from Example 3 is that an equal mass of the modified PBAT prepared in Preparation Example 6 is used to replace the PBAT in Example 3 to prepare the plastic film.

[0076] Example 10

[0077] The difference from Example 5 is that an equal mass of the modified PBAT prepared in Preparation Example 6 is used to replace the PBAT in Example 5 to prepare the plastic film.

[0078] Example 11

[0079] The difference from Example 5 is that an equal mass of the modified PBAT prepared in Preparation Example 7 is used to replace the PBAT in Example 5 to prepare the plastic film.

[0080] Example 12

[0081] The difference from Example 4 is that the composite film was placed in a sealed container containing 10 mL of 25% glutaraldehyde solution and crosslinked for 24 h to obtain a crosslinked film. The crosslinked film was washed with PBS buffer to prepare a mulch film.

[0082] Control example

[0083] Control example 1

[0084] The difference between this control example and Example 3 is that PPC was not added in this control example.

[0085] Performance detection test

[0086] (1) The tensile test of the mechanical properties of the mulch film was carried out with an electronic fabric strength tester. The tensile test conditions refer to GB / T 35795-2017 and GB / T 1040.3-2006. The specimen size was 150 mm in length * 10 mm in width, the initial distance between the clamps was 50 mm, and the test speed was 500 mm / min until the specimen broke. The maximum tensile load was measured, accurate to 0.01 N, and measured 5 times, and the average value was taken.

[0087] (2) Soil burial degradation performance detection: The composite film sample was buried 10 cm deep in the soil and taken out every 5 days. The taken-out sample was washed clean with deionized water, and its surface change was observed. When the sample was put back into the soil, a large amount of water was supplemented. Record the number of days of soil burial when a large number of purple mildew spots appeared on the mulch film, the film edge became thinner, and more cracks were generated.

[0088] (3) Nitrogen release amount test: The mulch film was evenly cut into rectangles of 30 mm * 40 mm, put into a 500 mL glass sample bottle with a lid, and 400 mL of 0.01 mol / L NaOH standard solution was added thereto. It was placed at room temperature. After one week, 1 mL of the alkaline solution was taken and diluted to 5 mL, and 1 drop of sulfuric acid was added to adjust the pH to 5-9. Take 4 mL of the sample into a total nitrogen digestion reagent tube, put in 1 oxidation tablet (reagent B), shake well, and heat in a 120 °C digester for 30 min. Cool to room temperature, add 5 mL of reagent C acid solution, mix well, take an appropriate amount of the solution into a quartz dish, and measure the total nitrogen content in the water using the Hach water quality meter program 358.

[0089] (4) Soil moisture retention performance detection: Pour the same mass of soil and water into a container to make the moisture content of the soil 40%. Cover the container with a mulch film, and select a container without covering any film as a control group. Weigh the total weight after 10 days and calculate the moisture content; Moisture content = (total weight of the container - weight of dry soil - total weight of the container after standing for ten days) / weight of dry soil × 100%, and record the decrease value of the soil moisture content.

[0090] Table 2 Performance detection

[0091]

[0092] It can be found by combining the performance detection and comparison in Table 2 that:

[0093] 1. By comparing Examples 1-3 with Comparative Example 1, it can be found that the breaking strength and moisture retention performance of the mulch films prepared in Examples 1-3 have both increased. This shows that in this application, by blending PBAT, PLA, and PPC to prepare the mulch film, the thermal stability of PPC can be effectively improved, and a mulch film with excellent film-forming properties and mechanical properties can be obtained. Since PBAT, PLA, and PPC are all biodegradable materials, using the above materials to blend and prepare the mulch film can obtain a biodegradable mulch film, eliminating the need for recycling the mulch film. This not only reduces production costs but also the residual film is less likely to have an adverse impact on the soil.

[0094] 2. By comparing Example 4 with Example 3, it can be found that the breaking strength and nitrogen content of the mulch film prepared in Example 3 have increased, while the moisture retention performance and soil burial degradation days have decreased. This shows that in this application, polar groups in collagen such as hydroxyl, carboxyl, and amino groups can cross-link and combine with the other components in the mulch film, increasing the cross-linking degree of the mulch film and improving its mechanical properties. And collagen is a biodegradable material that can decompose together with the mulch film material. Also, due to the relatively high nitrogen content in collagen, it can be converted into soil nitrogen fertilizer during the degradation process, supplementing nutrients for crops and the soil and saving the cost of fertilization. However, due to the presence of many hydrophilic groups in collagen, the hydrophobic and barrier properties of the mulch film have decreased.

[0095] 3. By comparing Examples 5-7 with Example 4, it can be found that the breaking strength and moisture retention performance of the mulch films prepared in Examples 5-7 have increased, while the nitrogen content has decreased. This shows that in this application, glycidyl methacrylate is used to modify collagen, enabling glycidyl methacrylate to graft onto collagen. As a result, long carbon chain structures and epoxy groups can be grafted onto collagen, effectively improving the hydrophobicity and heat resistance of collagen, thereby compensating for the hydrophobic and heat resistance losses brought by collagen in the mulch film and endowing the mulch film with excellent water resistance, heat insulation, and mechanical properties. Glycidyl methacrylate can also react with the terminal carboxyl groups of other components in the mulch film such as PBAT, increasing the molecular weight and thermal stability of PBAT, etc., and effectively improving the compatibility between collagen and the other components in the mulch film, further enhancing the structural stability and mechanical strength of the mulch film.

[0096] 4. By comparing Example 8 and Example 4, it can be found that the breaking strength and moisture retention performance of the plastic film prepared in Example 8 are improved, and the nitrogen content is decreased. This shows that in this application, ethanol is used to modify collagen. The alcohol hydroxyl group can carry out an esterification reaction with the carboxyl group on the side chain of the collagen molecule, effectively extending the molecular chain of collagen, and promoting the construction of a cross-linked network of collagen. It can reduce the hydrophilic groups in collagen, improve the binding effect between collagen and the other components in the plastic film, and improve the hydrophobicity of the plastic film.

[0097] 5. By comparing Example 9 and Example 3; and by comparing Examples 10 - 11 with Example 5, it can be found that the breaking strength and moisture retention performance of the plastic film prepared in Examples 9 - 11 are improved, and the nitrogen content is decreased. This shows that in this application, maleic anhydride can carry out a grafting reaction with PBAT through free radicals, and chain growth, chain transfer, and chain termination reactions occur, fully improving the compatibility of PBAT. After the acid anhydride group in maleic anhydride opens the ring, it can form a carboxyl group and combine with the active groups in collagen, improving the binding effect between collagen and the other components in the plastic film, enabling collagen and PBAT to enhance the interfacial force through chemical bonding, and improving the mechanical strength of the plastic film. And using glycidyl methacrylate and maleic anhydride to modify PBAT together can further improve the compatibility between the components in the plastic film, and stably improve the mechanical properties and barrier properties of the plastic film.

[0098] 6. By comparing Example 12 and Example 4, it can be found that the breaking strength and moisture retention performance of the plastic film prepared in Example 12 are improved, and the nitrogen content is decreased. This shows that in this application, the blow - molded product is placed in glutaraldehyde vapor. First, the aldehyde group in glutaraldehyde can react with the primary amine group in the material to form a Schiff base structure, thereby promoting cross - linking between the components in the plastic film, further improving the density of the plastic film, and further improving the hydrophobic property, barrier property, and mechanical property of the plastic film.

[0099] This specific embodiment is only an interpretation of this application, and it is not a limitation of this application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions as needed, but as long as it is within the scope of the claims of this application, it is protected by the patent law.

Claims

1. A degradable two-color ground film material, characterized in that: One side of the ground film is silver, and the other side of the ground film is black. The ground film includes the following materials in percentage by mass: PBAT 60-65%; PLA 5-10%; PPC 10-20%; 5-10% additives; the mulch film also includes 5-10% by mass of collagen, which is extracted from waste leather; The collagen is collagen modified by a modifier, and the modifier includes glycidyl methacrylate.

2. The degradable two-color ground film material according to claim 1, characterized in that: The preparation method of the collagen modified by the modifier is as follows: collagen, sodium sulfite and urea solution are mixed and stirred to obtain a collagen solution; glycidyl methacrylate and ammonium persulfate are added to the collagen solution, the reaction is kept warm, the solid is washed and centrifuged to retain the solid, the solid is washed with alcohol, filtered and dried to obtain the collagen modified by the modifier.

3. The degradable two-color ground film material according to claim 2, characterized in that: The mass ratio of the collagen to the glycidyl methacrylate is 1-2:1, and the reaction temperature is 60-90°C.

4. The degradable two-color ground film material according to claim 1, characterized in that: The modifying agent also includes ethanol.

5. The degradable two-color ground film material according to claim 1, characterized in that: The PBAT is PBAT modified by maleic anhydride.

6. The degradable two-color ground film material according to claim 5, characterized in that: The preparation of the maleic anhydride-modified PBAT is as follows: PBAT is mixed with xylene, heated in an oil bath to obtain a mixed solution, maleic anhydride and an initiator are added to the mixed solution, the reaction is continued, poured into an acetone solution, vacuum filtered, repeatedly purified, washed, and dried to obtain the maleic anhydride-modified PBAT.

7. A method for preparing a degradable two-color ground film material according to any one of claims 1 to 6, characterized in that: The method is as follows: drying PPC to obtain dry PPC, blending dry PPC, PLA, PBAT and additives, extruding and granulating, the extrusion temperature is 180-190° C., blow molding to obtain a composite film, coating silver paint and black paint on both sides of the composite film, and drying to obtain a ground film.

8. The method for preparing a degradable two-color ground film material according to claim 7, characterized in that: The blow-molded composite film is placed in glutaraldehyde vapor to obtain a ground film.

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