Degradable plastic film and preparation method thereof

Abstract

The invention relates to the technical field of plastic films, and provides a degradable plastic film and a preparation method thereof.The mode that microorganisms are placed between an inner layer film and an outer layer film in advance is adopted, auxiliary degradation of the degradable plastic film after use is achieved, the meeting and matching links of the degradable plastic film and the microorganisms in the external environment are reduced, and the degradation efficiency of the degradable plastic film is improved. The degradable plastic film is good in degradation environment matching performance and shorter in degradation period and comprises an inner-layer film and an outer-layer film, the inner-layer film and the outer-layer film are formed in a heating and rolling mode, a plurality of film-closing-free areas are arranged between the inner-layer film and the outer-layer film, microbial carriers are arranged in the multiple film-closing-free areas, and the microbial carriers are arranged between the inner-layer film and the outer-layer film. The inner layer film and the outer layer film are both formed by casting matrix plastic, and the matrix plastic is prepared from the following raw materials in parts by weight: 55 to 68 parts of polyvinyl chloride, 40 to 50 parts of polylactic acid, 22 to 28 parts of polyvinyl acetate, 15 to 20 parts of plant straw, 7 to 10 parts of ionic compound, 11 to 14 parts of flexibilizer, 14 to 20 parts of coupling agent and 13 to 16 parts of strength additive.

Description

Technical Field

[0001] The present invention relates to the technical field of plastic films, and in particular to a degradable plastic film and a preparation method thereof. Background Art

[0002] As we all know, in order to solve the "white pollution" problem caused by traditional plastic films, we propose a degradable plastic film and a preparation method thereof. Degradable plastic film is a plastic film that can be decomposed into harmless substances in a natural environment or under specific conditions.

[0003] After searching, the invention patent with Chinese patent application number CN202011432007.2 discloses a degradable plastic film and its preparation method, which is roughly described as comprising the following raw material compositions in parts by weight: 100-200 parts of polylactic acid, 10-15 parts of metal-organic framework material, and 20-80 parts of thermoplastic starch. In the metal-organic framework material, the metal element is in a single atomic state and combined with the organic framework. During the preparation, the preparation of thermoplastic starch is as follows: 1-5% of D-sorbitol by weight of starch is added to the starch, and after heating and shearing, thermoplastic starch is obtained. The preparation of the matrix plastic is as follows: polylactic acid and thermoplastic starch are heated and blended, and then metal-organic framework material and graphene oxide are added. After continuing to heat and blend, extrusion and granulation are performed to obtain the matrix plastic. The preparation of the product is as follows: the matrix plastic is cast into a film to obtain a degradable plastic film.

[0004] Although the above-mentioned prior art solution provides a degradable plastic film, the degradation of plastic also requires a certain environment and specific microorganisms to initiate the degradation process. These microorganisms can secrete enzymes to decompose the plastic film into small molecules. For example, polylactic acid can be degraded by some microorganisms in the soil. In the soil environment, there are specific bacteria and fungi that can recognize and decompose polylactic acid. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a degradable plastic film and a preparation method thereof, which adopts the method of pre-placing microorganisms between the inner film and the outer film to achieve auxiliary degradation of the degradable plastic film after use, reducing the encounter and matching links between the degradable plastic film and the microorganisms in the external environment. The degradation environment of the degradable plastic film is better matched, and the degradation cycle of the degradable plastic film is shorter. At the same time, the preparation device of the degradable plastic film formed in conjunction with the preparation device can realize the distribution of microorganisms between the inner film and the outer film, so as to facilitate the corresponding production of the degradable plastic film.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a degradable plastic film, comprising an inner layer film and an outer layer film, wherein the inner layer film and the outer layer film are formed by heated rolling, and a plurality of mold-free areas are provided between the inner layer film and the outer layer film, and microbial carriers are provided in the plurality of mold-free areas, and the inner layer film and the outer layer film are both formed by casting a base plastic.

[0007] Preferably, the matrix plastic comprises the following raw materials in parts by weight: 55-68 parts of polyvinyl chloride, 40-50 parts of polylactic acid, 22-28 parts of polyvinyl acetate, 15-20 parts of plant straw, 7-10 parts of ionic compound, 11-14 parts of toughening agent, 14-20 parts of coupling agent and 13-16 parts of strength additive.

[0008] Preferably, the microorganism carrier is a porous plastic carrier prepared by a foaming process, and the porous structure provides space for microorganisms to attach and grow.

[0009] A preparation device for a degradable plastic film comprises a mounting frame, a mold clamping assembly and a uniform spreading assembly, wherein the mold clamping assembly comprises a support roller and a mold clamping roller, wherein the support roller adopts a smooth surface design, and a plurality of recessed grooves are provided on the mold clamping roller, wherein the plurality of recessed grooves form a cover for the mold clamping roller, and the support roller and the mold clamping roller are both mounted in the mounting frame, and two first servo motors are mounted on the mounting frame, wherein the two first servo motors are respectively used for driving the rotation of the support roller and the mold clamping roller, and the uniform spreading assembly comprises a through-distribution cylinder, wherein the through-distribution cylinder is fixedly connected in the mounting frame and passes through the bottom end of the distributing cylinder. A plurality of circular holes are opened, and an inclined tube rack is rotatably connected in each of the circular holes, and a telescopic material distributing cylinder and a material receiving and conveying cylinder are slidably connected in each of the inclined tube racks, and a transmission structure is installed in each of the inclined tube racks, and the transmission structure is used for the relative transmission movement of the telescopic material distributing cylinder and the material receiving and conveying cylinder, and a lower semicircular opening is opened at the lower end head of each of the telescopic material distributing cylinders, and a material blocking rack is fixedly connected in each of the inclined tube racks, and the multiple material blocking racks are respectively matched with the multiple lower semicircular openings, and a swinging drive structure is installed in the mounting frame, and the swinging drive structure is used for the synchronous drive of the multiple material receiving and conveying cylinders.

[0010] Preferably, the swing drive structure includes a cross sleeve and a second servo motor, the cross sleeve is fixedly connected in the mounting frame, the drive frame is slidably connected in the cross sleeve, a plurality of drive holes are opened on the drive frame, a plurality of drive holes are provided with a stepped linkage shaft, and the plurality of stepped linkage shafts are respectively fixedly connected to a plurality of material receiving and conveying cylinders, the second servo motor is installed on the outside of the mounting frame, and a drive disk is fixedly connected to the output shaft of the second servo motor, an eccentric shaft is fixedly connected to the drive disk, a linkage rod is rotatably connected to the eccentric shaft, and the linkage rod is rotatably connected to the drive frame.

[0011] Preferably, a side opening is provided on the mounting frame, and the driving frame extends out of the mounting frame through the side opening. A plurality of the inclined tube racks are provided with through holes, and a plurality of the material receiving and conveying cylinders are respectively slidably fitted in the plurality of through holes. A plurality of the material receiving and conveying cylinders are provided with a notch, and the notch is used for connecting the material receiving and conveying cylinder with the inclined tube rack.

[0012] Preferably, both left and right ends of the distributing cylinder are connected with feeding pipes, the two feeding pipes are connected with elbows, and the two elbows are connected with feeding hoppers.

[0013] Preferably, the plurality of transmission structures include a first transmission rack, a second transmission rack and a synchronous gear, the plurality of synchronous gears are rotatably connected in the plurality of inclined tube racks, the plurality of first transmission racks are respectively engaged with the plurality of synchronous gears, the plurality of second transmission racks are respectively engaged with the plurality of synchronous gears, the plurality of first transmission racks are respectively fixedly connected with the plurality of material receiving and conveying cylinders, and the plurality of second transmission racks are respectively fixedly connected with the plurality of telescopic material distributing cylinders.

[0014] Preferably, a lifting frame is slidably connected to the mounting frame, the support roller is rotatably connected to the lifting frame, a first servo motor for rotating the support roller is installed on the lifting frame, a leveling support plate is installed on the lifting frame, the bottom end of the lifting frame is fixedly connected to an elastic spring, the bottom end of the elastic spring is fixedly connected to a connecting plate, the bottom end of the connecting plate is rotatably connected to a threaded rod, and the threaded rod is threadedly connected to the mounting frame.

[0015] A method for preparing a degradable plastic film comprises the following steps:

[0016] S1. During preparation, the outer film layer is first controlled to pass through the top of the distribution drum, and the inner film layer is controlled to pass through the bottom of the distribution drum, and finally both the inner film and the outer film layer are passed through the gap between the support roller and the mold closing roller, and the multiple inclined tube racks are all located in the area between the support roller and the mold closing roller;

[0017] S2: Then, granular material of the microorganism carrier is fed into the material distributing cylinder, and the heating resistor in the die-closing roller is turned on to increase the temperature of the die-closing roller. Then, two first servo motors and an oscillating drive structure are started. The two first servo motors work to realize the synchronous relative rotation drive of the support roller and the die-closing roller, and then the inner layer film and the outer layer film passing through the gap between the support roller and the die-closing roller are assisted in ironing and forming.

[0018] S3. The swing drive structure is powered on to realize the movement drive of the material receiving and conveying cylinder. The movement of the material receiving and conveying cylinder and the telescopic cloth cylinder will form a linkage, and then the material blocking rack is adapted and adjusted relative to the lower semicircular opening, so that the microbial carrier passing through the cloth cylinder is guided by the inclined tube rack, the telescopic cloth cylinder and the material receiving and conveying cylinder to enter between the inner and outer membranes, and the area between the inner and outer membranes where the granular material enters is controlled to be an area that cannot be hot-pressed by the mold closing roller.

[0019] Compared with the prior art, the present invention provides a degradable plastic film and a preparation method thereof, which has the following beneficial effects:

[0020] (1) In the present invention, a degradable plastic film containing microorganisms is formed through the design of a degradable plastic film. The microorganisms are pre-placed between the inner film and the outer film to achieve auxiliary degradation of the degradable plastic film after use, thereby reducing the encounter and matching links between the degradable plastic film and the microorganisms in the external environment. The degradation environment of the degradable plastic film is better matched, and the degradation cycle of the degradable plastic film is shorter.

[0021] (2) In the present invention, by designing a preparation device for a degradable plastic film, a corresponding preparation device is formed with a matching degradable plastic film, thereby realizing auxiliary preparation of the degradable plastic film. At the same time, the distribution of microorganisms relative to the inner film and the outer film can be realized to facilitate the corresponding production of the degradable plastic film. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the three-dimensional structure of a device for preparing a degradable plastic film according to the present invention;

[0023] Figure 2 It is a partially cutaway perspective structural diagram of the coordination of the distribution drum, the inclined tube rack and the telescopic distribution drum of the present invention;

[0024] Figure 3 For the present invention Figure 2 Schematic diagram of the local enlarged structure at A in the middle;

[0025] Figure 4 It is a schematic diagram of a sectional exploded three-dimensional structure of the inclined pipe rack, the telescopic material distribution cylinder and the material receiving and conveying cylinder of the present invention;

[0026] Figure 5 This is a schematic diagram of the three-dimensional structure of the lifting frame, leveling support plate and elastic spring of the present invention;

[0027] Figure 6 This is a schematic diagram of the three-dimensional structure of a device for preparing a degradable plastic film according to the present invention from another angle;

[0028] Figure 7This is a bottom-up schematic diagram of the three-dimensional structure of a device for preparing a degradable plastic film according to the present invention;

[0029] Figure 8 This is a bottom-up schematic diagram of the three-dimensional structure of the supporting rollers, lifting frame and leveling support plate of the present invention;

[0030] Figure 9 This is a schematic diagram of the three-dimensional structure of a degradable plastic film of the present invention.

[0031] In the figure: 1. Mounting frame; 2. Support roller; 3. Clamping roller; 4. Recessed groove; 5. First servo motor; 6. Through-feeding drum; 7. Oblique tube rack; 8. Telescopic feeding drum; 9. Material receiving and conveying drum; 10. Lower semicircular opening; 11. Material blocking rack; 12. Cross sleeve; 13. Second servo motor; 14. Driving frame; 15. Driving hole; 16. Step linkage shaft; 17. Driving disk; 18. Eccentric shaft; 19. Linkage rod; 20. Side opening; 21. Through-hole; 22. Notch; 23. Feeding pipe; 24. Elbow; 25. Feeding hopper; 26. First transmission rack; 27. Second transmission rack; 28. Synchronous gear; 29. Lifting frame; 30. Leveling support plate; 31. Elastic spring; 32. Connecting plate; 33. Threaded rod. DETAILED DESCRIPTION

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 are within the scope of protection of the present invention.

[0033] Example

[0034] See also Figures 1-9A degradable plastic film comprises an inner layer and an outer layer, wherein the inner layer and the outer layer are formed by heating and rolling, and a plurality of mold-free regions are provided between the inner layer and the outer layer, wherein microorganism carriers are provided in the plurality of mold-free regions, and the inner layer and the outer layer are both formed by casting a base plastic, wherein the base plastic comprises the following raw materials in parts by weight: 55-68 parts of polyvinyl chloride, 40-50 parts of polylactic acid, 22-28 parts of polyvinyl acetate, 15-20 parts of plant straw, 7-10 parts of ionic compound, 11-14 parts of toughening agent, and 14-20 parts of coupling agent. The microbial carrier is a porous plastic carrier prepared by a foaming process. The porous structure provides space for microorganisms to attach and grow. A degradable plastic film containing microorganisms is formed through the design of the degradable plastic film. The microorganisms are pre-placed between the inner film and the outer film to achieve auxiliary degradation of the degradable plastic film after use, which reduces the encounter and matching links between the degradable plastic film and the microorganisms in the external environment. The degradation environment of the degradable plastic film is better matched, and the degradation cycle of the degradable plastic film is shorter.

[0035] It should be further explained that a device for preparing a degradable plastic film includes a mounting frame 1, a mold clamping assembly and a spreading assembly. The mold clamping assembly includes a support roller 2 and a mold clamping roller 3. The support roller 2 adopts a smooth design. The mold clamping roller 3 is provided with a plurality of recessed grooves 4. The plurality of recessed grooves 4 form a cover for the mold clamping roller 3. The support roller 2 and the mold clamping roller 3 are both mounted in the mounting frame 1, and two first servo motors 5 are installed on the mounting frame 1. The two first servo motors 5 are respectively used for the rotation drive of the support roller 2 and the rotation drive of the mold clamping roller 3. A lifting frame 29 is slidably connected in the mounting frame 1, and the support roller 2 is rotatably connected in the lifting frame 29. The first servo motor 5 for the rotation drive of the support roller 2 is installed in the lifting frame. On the lowering frame 29, a leveling support plate 30 is installed on the lifting frame 29, the bottom end of the lifting frame 29 is fixedly connected to an elastic spring 31, the bottom end of the elastic spring 31 is fixedly connected to a connecting plate 32, the bottom end of the connecting plate 32 is rotatably connected to a threaded rod 33, and the threaded rod 33 is threadedly connected to the mounting frame 1, so that the support roller 2 can be adjusted relative to the mold closing roller 3, so that the relative pressure between the support roller 2 and the mold closing roller 3 is auxiliary adjusted, and the evenly spreading component includes a material passing through the cloth barrel 6, and the left and right ends of the material passing through the cloth barrel 6 are connected with a feeding pipe 23, and the two feeding pipes 23 are connected with an elbow 24, and the two elbows 24 are connected with a feeding hopper 25, which is convenient for feeding the microbial carrier into the material passing through the cloth barrel 6.

[0036] It should be further explained that the material distributing cylinder 6 is fixedly connected to the mounting frame 1, and a plurality of circular holes are provided at the bottom end of the material distributing cylinder 6. The plurality of circular holes are rotatably connected to the inclined tube rack 7, and the plurality of inclined tube racks 7 are slidably connected to the telescopic material distributing cylinder 8 and the material receiving and conveying cylinder 9. The plurality of inclined tube racks 7 are installed with transmission structures, and the plurality of transmission structures include a first transmission rack 26, a second transmission rack 27 and a synchronous gear 28. The plurality of synchronous gears 28 are respectively rotatably connected to the plurality of inclined tube racks 7, and the plurality of first transmission racks 26 are respectively engaged with the plurality of synchronous gears 28, and the plurality of second transmission racks 27 are respectively engaged with the plurality of synchronous gears 28. The gear 28 is engaged, and the multiple first transmission racks 26 are respectively fixedly connected to the multiple material receiving and conveying cylinders 9, and the multiple second transmission racks 27 are respectively fixedly connected to the multiple telescopic material distributing cylinders 8. The transmission structure is used for the relative transmission movement of the telescopic material distributing cylinder 8 and the material receiving and conveying cylinder 9. The lower end heads of the multiple telescopic material distributing cylinders 8 are all provided with lower semicircular openings 10. The multiple inclined tube racks 7 are all fixedly connected with material blocking racks 11. The multiple material blocking racks 11 are matched with the multiple lower semicircular openings 10 respectively. Through the design of the preparation device of the degradable plastic film, the corresponding preparation device is formed with the matching degradable plastic film to realize the auxiliary preparation of the degradable plastic film. It can realize the distribution of microorganisms relative to the inner membrane and the outer membrane to facilitate the corresponding production of the degradable plastic film. A swing drive structure is installed in the mounting frame 1. The swing drive structure includes a cross sleeve 12 and a second servo motor 13. The cross sleeve 12 is fixedly connected in the mounting frame 1. A driving frame 14 is slidably connected in the cross sleeve 12. A plurality of driving holes 15 are opened on the driving frame 14. A stepped linkage shaft 16 is provided in each of the plurality of driving holes 15. The plurality of stepped linkage shafts 16 are respectively fixedly connected to a plurality of material receiving and conveying cylinders 9. The second servo motor 13 is installed on the outside of the mounting frame 1, and the second servo motor 13 is A driving disk 17 is fixedly connected to the output shaft, an eccentric shaft 18 is fixedly connected to the driving disk 17, a linkage rod 19 is rotatably connected to the eccentric shaft 18, the linkage rod 19 is rotatably connected to the driving frame 14, a side opening 20 is provided on the mounting frame 1, the driving frame 14 extends out of the mounting frame 1 through the side opening 20, and multiple inclined tube racks 7 are each provided with a through hole 21, and multiple material receiving and conveying cylinders 9 are respectively slidably fitted in the multiple through holes 21, and multiple material receiving and conveying cylinders 9 are each provided with a strip notch 22, which is used for connecting the material receiving and conveying cylinder 9 with the inclined tube rack 7, and the swinging drive structure is used for synchronous driving of multiple material receiving and conveying cylinders 9.

[0037] The first servo motor 5 and the second servo motor 13 in this embodiment are conventional devices purchased on the market and well known to those skilled in the art. In the present invention, we only use them without improving their structure and function. For those skilled in the art, their setting method, installation method and electrical connection method only need to be debugged according to the requirements of their instruction manual, and will not be described in detail here.

[0038] In summary, the working principle of the degradable plastic film and its preparation method is that, when in use, the preparation device of the degradable plastic film is first installed at the desired location, and the first servo motor 5 and the second servo motor 13 are connected to the corresponding control circuit according to their respective instructions. During preparation, the outer film layer is first controlled to bypass from the top of the through-distribution drum 6, and the inner film is controlled to bypass from the bottom of the through-distribution drum 6, and finally the inner film and the outer film are both passed through the gap between the support roller 2 and the mold closing roller 3. A plurality of inclined tube racks 7 are all located in the area between the support roller 2 and the mold closing roller 3, and then the through-distribution drum 6 is fed into the through-distribution drum 6. The granular material of the microbial carrier is connected, and the heating resistor in the mold closing roller 3 is turned on to increase the temperature of the mold closing roller 3. Then, the two first servo motors 5 and a swing drive structure are started. The two first servo motors 5 work to realize the synchronous relative rotation drive of the support roller 2 and the mold closing roller 3, and then the inner layer film and the outer layer film at the gap between the support roller 2 and the mold closing roller 3 are assisted in ironing and forming. The swing drive structure is powered on to drive the second servo motor 13. The second servo motor 13 works through the drive disk 17, the eccentric shaft 18 and the linkage rod 19 to realize the movement drive of the drive frame 14 relative to the cross sleeve 12, and multiple step linkages are formed. Under the transmission action of the shaft 16, the moving driving frame 14 will realize the movement drive of the material receiving and conveying drum 9. The movement of the material receiving and conveying drum 9 will form a linkage through the linkage transmission of the first transmission rack 26, the second transmission rack 27 and the synchronous gear 28 to drive the telescopic material distributing drum 8, and then achieve the adaptive adjustment of the material blocking frame 11 relative to the lower semicircular opening 10. When the material receiving and conveying drum 9 enters the state of left swing or right swing under the drive of the driving frame 14, the material receiving and conveying drum 9 will be pulled backward relative to the inclined tube rack 7, and the telescopic material distributing tube will be formed to extend forward relative to the inclined tube rack 7. In the forward extending state, the material blocking frame 11 will be relative to the telescopic material distributing drum The cylinder 8 moves backward to expose the lower semicircular opening 10, so that the granular material passing through the distributing cylinder 6 forms a distributing channel, thereby achieving the microbial carrier passing through the distributing cylinder 6 and entering between the inner film and the outer film through the guidance of the inclined tube rack 7, the telescopic distributing cylinder 8 and the material receiving and conveying cylinder 9, so as to facilitate the distribution of the granular material onto the inner film, and the area where the granular material is guided and distributed into the inner film corresponds to the concave groove 4 on the die-closing roller 3 to be rolled, and the area between the inner film and the outer film where the granular material enters is controlled to be the area that the die-closing roller 3 cannot iron and press, that is, the film-free area. The degradable plastic film finally formed is as shown in the attached Figure 9As shown, during the movement of the material receiving and conveying cylinder 9 between the left swinging or right swinging states, the material receiving and conveying cylinder 9 is pushed inward relative to the inclined tube rack 7, and the part of the telescopic material distributing cylinder 8 extending relative to the inclined tube rack 7 is also retracted into the inclined tube rack 7, and the material blocking rack 11 is relatively inserted relative to the lower semicircular opening 10, so that the telescopic material distributing cylinder 8 is relatively closed, thereby achieving the effect of hindering the outflow of granular material, preventing the inner and outer films from interfering with each other during the swinging movement of the telescopic material distributing cylinder 8, and also preventing the granular material from entering the heated rolling area between the inner and outer films.

[0039] Further, as attached Figure 9 As shown, since the granular material containing the microbial carrier between the inner film and the outer film is enclosed in a relatively independent and closed space, the microorganisms in the granular material are in a relatively dormant state under anaerobic conditions. In order to facilitate the survival of microorganisms in anaerobic conditions, the types of microorganisms should be selected accordingly, and the survival rate of microorganisms can be improved by pre-adding nutrients into the granular material. After actual use, if the degradable plastic film is damaged and air enters the relatively independent and closed space, the microorganisms will be exposed to oxygen and grow and reproduce, thereby forming an auxiliary degradation of the degradable plastic film. The specific steps for preparing the inner film and the outer film are as follows: crush the plant straw, soak it with 8.5% sodium hydroxide solution (the mass ratio of sodium hydroxide solution to plant straw is 1:18), filter it after soaking for 15h-19h, and wash the plant straw powder and dry it , and then put it into a mixed solution of 0.2% lime and 0.8% sodium hypochlorite for 30h-40h (the mass ratio of the mixed solution to the plant straw is 1:35), filtered after soaking and dried to obtain plant straw powder, the plant straw powder prepared above and polyvinyl chloride, polylactic acid, polyvinyl acetate, toughening agent and coupling agent are mixed in a high-speed mixer, added to the barrel of a twin-screw extruder and heated at 240-280°C, and extruded through a die (extrusion temperature is 250°C-270°C) to obtain a masterbatch, the masterbatch is mixed with an ionic compound and a strength additive, added to the barrel of a film blowing machine and heated at 190°C-200°C, extruded through a die at 200°C-210°C, entered into a die head, and blown into shape (blowing ratio is 1.7-1.8), and pulled into a roller at a traction speed of 20m / min-30m / min to obtain a film.

[0040] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A degradable plastic film, characterized in that: It includes an inner layer film and an outer layer film, which are formed by heating and rolling, and a plurality of mold-free areas are arranged between the inner layer film and the outer layer film, and microbial carriers are arranged in the plurality of mold-free areas. The inner layer film and the outer layer film are both formed by casting a base plastic.

2. A degradable plastic film according to claim 1, characterized in that: The matrix plastic comprises the following raw materials in parts by weight: 55-68 parts of polyvinyl chloride, 40-50 parts of polylactic acid, 22-28 parts of polyvinyl acetate, 15-20 parts of plant straw, 7-10 parts of ionic compound, 11-14 parts of toughening agent, 14-20 parts of coupling agent and 13-16 parts of strength additive.

3. A degradable plastic film according to claim 2, characterized in that: The microorganism carrier is a porous plastic carrier prepared by a foaming process, and the porous structure provides space for microorganisms to attach and grow.

4. A device for preparing a degradable plastic film, characterized in that: The invention comprises a mounting frame (1), a mold clamping assembly and a uniform spreading assembly, wherein the mold clamping assembly comprises a support roller (2) and a mold clamping roller (3), wherein the support roller (2) adopts a smooth surface design, and the mold clamping roller (3) is provided with a plurality of recessed grooves (4), and the plurality of recessed grooves (4) form a cover for the mold clamping roller (3), and the support roller (2) and the mold clamping roller (3) are both mounted in the mounting frame (1), and two first servo motors (5) are mounted on the mounting frame (1), and the two first servo motors (5) are respectively used for driving the rotation of the support roller (2) and the rotation of the mold clamping roller (3), and the uniform spreading assembly comprises a through-distribution barrel (6), wherein the through-distribution barrel (6) is fixedly connected in the mounting frame (1), and the bottom end of the through-distribution barrel (6) is opened. A plurality of circular holes are provided, wherein the plurality of circular holes are rotatably connected to an inclined tube rack (7), wherein the plurality of inclined tube racks (7) are slidably connected to a telescopic material distributing cylinder (8) and a material receiving and conveying cylinder (9), wherein the plurality of inclined tube racks (7) are installed with a transmission structure, wherein the transmission structure is used for the relative transmission movement of the telescopic material distributing cylinder (8) and the material receiving and conveying cylinder (9), wherein the lower end heads of the plurality of telescopic material distributing cylinders (8) are provided with a lower semicircular opening (10), wherein the plurality of inclined tube racks (7) are fixedly connected to a material blocking rack (11), wherein the plurality of the material blocking racks (11) are matched with the plurality of the lower semicircular openings (10) respectively, and wherein a swing driving structure is installed in the mounting frame (1), wherein the swing driving structure is used for the synchronous driving of the plurality of the material receiving and conveying cylinders (9).

5. The device for preparing a degradable plastic film according to claim 4, characterized in that: The swing drive structure comprises a cross sleeve (12) and a second servo motor (13), wherein the cross sleeve (12) is fixedly connected in the mounting frame (1), and a driving frame (14) is slidably connected in the cross sleeve (12), and a plurality of driving holes (15) are provided on the driving frame (14), and a plurality of step linkage shafts (16) are provided in each of the plurality of driving holes (15), and the plurality of step linkage shafts (16) are respectively fixedly connected to a plurality of material receiving and conveying cylinders (9), and the second servo motor (13) is mounted on the outside of the mounting frame (1), and a driving disk (17) is fixedly connected to the output shaft of the second servo motor (13), an eccentric shaft (18) is fixedly connected to the driving disk (17), a linkage rod (19) is rotatably connected to the eccentric shaft (18), and the linkage rod (19) is rotatably connected to the driving frame (14).

6. The device for preparing a degradable plastic film according to claim 5, characterized in that: The mounting frame (1) is provided with a side opening (20), the driving frame (14) extends out of the mounting frame (1) through the side opening (20), a plurality of the inclined tube racks (7) are provided with through holes (21), a plurality of the material receiving and conveying cylinders (9) are respectively slidably fitted in the plurality of through holes (21), and a plurality of the material receiving and conveying cylinders (9) are provided with a strip notch (22), and the strip notch (22) is used for connecting the material receiving and conveying cylinders (9) with the inclined tube racks (7).

7. The device for preparing a degradable plastic film according to claim 6, characterized in that: The left and right ends of the distributing cylinder (6) are both connected with feeding pipes (23), the two feeding pipes (23) are connected with elbows (24), and the two elbows (24) are both connected with feeding hoppers (25).

8. The device for preparing a degradable plastic film according to claim 7, characterized in that: The plurality of transmission structures each include a first transmission rack (26), a second transmission rack (27) and a synchronous gear (28); the plurality of synchronous gears (28) are rotatably connected to the plurality of inclined tube racks (7); the plurality of first transmission racks (26) are respectively engaged with the plurality of synchronous gears (28); the plurality of second transmission racks (27) are respectively engaged with the plurality of synchronous gears (28); the plurality of first transmission racks (26) are respectively fixedly connected to the plurality of material receiving and conveying cylinders (9); and the plurality of second transmission racks (27) are respectively fixedly connected to the plurality of telescopic material distributing cylinders (8).

9. The device for preparing a degradable plastic film according to claim 8, characterized in that: A lifting frame (29) is slidably connected to the mounting frame (1), the support roller (2) is rotatably connected to the lifting frame (29), a first servo motor (5) for rotatably driving the support roller (2) is mounted on the lifting frame (29), a leveling support plate (30) is mounted on the lifting frame (29), an elastic spring (31) is fixedly connected to the bottom end of the lifting frame (29), a connecting plate (32) is fixedly connected to the bottom end of the elastic spring (31), a threaded rod (33) is rotatably connected to the bottom end of the connecting plate (32), and the threaded rod (33) is threadedly connected to the mounting frame (1).

10. A method for preparing a degradable plastic film, characterized in that: The device for preparing a degradable plastic film according to any one of claims 4 to 9 is used, comprising the following steps: S1. During preparation, the outer film layer is first controlled to pass through the top of the through-distribution cylinder (6), and the inner film layer is controlled to pass through the bottom of the through-distribution cylinder (6), and finally both the inner film layer and the outer film layer are passed through the gap between the support roller (2) and the mold closing roller (3), and the plurality of inclined tube racks (7) are all located in the area between the support roller (2) and the mold closing roller (3); S2, then the granular material of the microorganism carrier is fed into the material distributing cylinder (6), and the heating resistor in the mold closing roller (3) is connected to increase the temperature of the mold closing roller (3), and then the two first servo motors (5) and the swing drive structure are started. The two first servo motors (5) work to realize the synchronous relative rotation drive of the support roller (2) and the mold closing roller (3), and then the inner layer film and the outer layer film at the gap between the support roller (2) and the mold closing roller (3) are assisted in hot connection and forming; S3, the swing drive structure is powered on to realize the motion drive of the material receiving and conveying cylinder (9), and the movement of the material receiving and conveying cylinder (9) and the telescopic cloth cylinder (8) will form a linkage, and then the material blocking frame (11) is adapted and adjusted relative to the lower semicircular opening (10), so that the microbial carrier passing through the cloth cylinder (6) is guided by the inclined tube frame (7), the telescopic cloth cylinder (8) and the material receiving and conveying cylinder (9) to enter between the inner layer membrane and the outer layer membrane, and the area between the inner layer membrane and the outer layer membrane where the granular material enters is controlled to be an area that cannot be pressed by the mold closing roller (3).

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