Production method of environment-friendly PET co-extrusion plate with multi-layer structure

Abstract

The invention relates to the technical field of PET plate production, in particular to a production method of an environment-friendly PET co-extrusion plate with a multi-layer structure. Comprising the following steps: S1, a PET core material is extruded in a twin-screw and single-screw splicing extruder, PET particles are used as a main formula, a nucleating agent, a chain extender and an antioxidant are added, and the PET core material is a food-grade PET polymer environment-friendly material, and S2, upper and lower surface decoration layers are also extruded in the twin-screw and single-screw splicing extruder and placed on the upper and lower surfaces of a PET plate discharged from a foaming port; the PET core material is a food-grade PET high-molecular environment-friendly material, the material is not temporarily used as a decorative plate on the market, the PET core material is integrally bonded to be a molten PET body, does not contain any glue component, is the same in product and material, is PET and can be directly recycled, wood cutting is completely eradicated, the nature is protected, meanwhile, the surface material can be made into any density, any thickness and any color, and the surface material can be used for decoration. Various textures can be pressed, the product is environment-friendly, and the finished product is free of harmful gas emission.

Description

Technical Field

[0001] The invention relates to the technical field of PET board production, in particular to a production method of a multi-layered environmentally friendly PET co-extruded board. Background Art

[0002] As a thermoplastic polyester material, PET has excellent physical and mechanical properties, weather resistance, chemical resistance and recyclability. It is widely used in packaging, construction, electronics, automobiles, textiles and other fields.

[0003] At present, most of the composite boards available in the market are multi-layer boards, particle boards, density boards, etc. Multi-layer boards: usually refers to a plate-like material made of multiple layers of veneer bonded by adhesives; particle boards: a kind of man-made board pressed at high temperature, its main raw materials are branches, fast-growing wood, sawdust, glue, etc.; density boards: wood fibers or other plant fibers are the main raw materials. The above boards are all made by preparing fibers, applying synthetic glue, and pressing under heating and pressure conditions. However, composite boards have the problems of being heavy, containing TVOC harmful gases such as formaldehyde and benzene, the highest environmental protection level E0 or ENF, being flammable when exposed to fire, absorbing water, being easy to deform, and being felled. Trees are non-renewable resources and cannot be recycled.

[0004] Therefore, a production method of a multi-layer structure environmentally friendly PET co-extruded board is urgently needed to solve the existing technical problems. Summary of the invention

[0005] The object of the present invention is to provide a method for producing a multi-layered environmentally friendly PET co-extruded board to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides a method for producing a multi-layered environmentally friendly PET co-extruded board, comprising a decorative layer, a PET core material, a shaping roller, an extrusion device, an extrusion mechanism, an unwinding mechanism and a pressing mechanism, and the specific steps are as follows:

[0007] S1. PET core material is extruded by twin-screw + single-screw splicing extruder, with PET polyester particles as the main formula, plus nucleating agent, chain extender, antioxidant, and PET core material is food-grade PET polymer environmentally friendly material;

[0008] S2, the upper and lower surface decorative layers are also extruded by a twin-screw + single-screw splicing extruder and placed on the upper and lower surfaces of the PET sheet coming out of the foaming port;

[0009] S3. The finished product after preliminary merging can be bonded to various decorative layers on the surface as a whole because the PET core material foamed inside is still in a molten state, and then pressed by the pressure of the shaping roller to ensure the thickness and surface flatness of the product;

[0010] S4. After forming, the product will go through the process of trimming, applying protective film, and slitting into the length and width required by the customer to form the final product;

[0011] S5. After the pressure relief is completed, the product is placed in a designated constant temperature and humidity room for curing to ensure the quality of the final product;

[0012] The pressing mechanism comprises a lower conveying platform, a shaping roller is installed on one side of the upper surface of the lower conveying platform, a conveying belt 2 is connected to the surface of the shaping roller, a meshing gear is connected to one side of the surface of the conveying belt 2, a middle conveying platform and an upper conveying platform are installed on the upper surface of the lower conveying platform, mounting plates are installed on both sides of the upper surfaces of the middle conveying platform and the upper conveying platform, an elastic spring is installed at the center of the surface of the mounting plate, a slider is connected to one side of the surface of the elastic spring, a connecting rod is connected to one side of the surface of the slider, an adjusting plate is sleeved at the center of the outer surface of the connecting rod, an upper pressing plate and a middle pressing plate are connected to the back surface of the slider, a positioning groove is provided on one side of the surface of the lower conveying platform, and the lower surface of the adjusting plate is in rotational meshing contact with the outer surface of the meshing gear, so that the upper pressing plate and the middle pressing plate are adjusted up and down on the upper surfaces of the middle conveying platform and the upper conveying platform;

[0013] As a further improvement of the present technical solution, the extrusion equipment includes a shell, a fixed base is installed on the left side of the lower surface of the shell, and feed port 1, feed port 2 and feed port 3 are arranged on the upper surface of the shell, and feed port 1, feed port 2 and feed port 3 are connected to the interior of the extrusion mechanism correspondingly.

[0014] As a further improvement of the present technical solution, the extrusion mechanism includes a driving motor 1, a driving gear is fixedly connected to one side of the surface of the driving motor 1, a conveyor belt is meshed on the outer surface of the driving gear, an upper single screw conveying rod, a middle double screw conveying rod and a lower single screw conveying rod are fixedly sleeved on one side of the surface of the driving gear, an upper extrusion groove, a middle extrusion groove and a lower extrusion groove are arranged on the outer surfaces of the upper single screw conveying rod, the middle double screw conveying rod and the lower single screw conveying rod, the upper single screw conveying rod, the middle double screw conveying rod and the lower single screw conveying rod are distributed in a diamond shape as a whole inside the extrusion equipment, and the upper single screw conveying rod, the middle double screw conveying rod and the lower single screw conveying rod rotate synchronously through the driving gear and the conveyor belt.

[0015] As a further improvement of the present technical solution, the unwinding mechanism includes a driving motor 2, a unwinding roller is connected to one side of the surface of the driving motor 2, a rotating gear is connected to one side of the surface of the unwinding roller, a transmission belt 1 is connected to the outer surface of the rotating gear, and there are two unwinding rollers in total. The two unwinding rollers are symmetrically distributed at the upper and lower ends of the right side of the surface of the extrusion equipment, and the two unwinding rollers rotate synchronously through the rotating gear and the transmission belt 1.

[0016] As a further improvement of the present technical solution, the bottom surfaces of the upper extrusion groove, the middle extrusion groove and the lower extrusion groove are all provided with opening and closing plates and sensors, the sensors are temperature sensors, and the opening and closing plates are adjusted by the sensors on the bottom surfaces of the upper extrusion groove, the middle extrusion groove and the lower extrusion groove.

[0017] As a further improvement of the present technical solution, one side of the surface of the lower conveyor platform, the middle conveyor platform and the upper conveyor platform is parallelly connected to the surfaces of the upper extrusion groove, the middle extrusion groove and the lower extrusion groove, and the lower surfaces of the middle conveyor platform and the upper conveyor platform are correspondingly connected to the surface of the lower conveyor platform.

[0018] As a further improvement of the technical solution, the upper and lower sides of the two unwinding rollers are connected to the upper pressing plate and the positioning groove correspondingly, the lower unwinding roller passes through the positioning groove and fits with the surface of the lower conveying platform, and is connected to one side of the lower extrusion groove surface correspondingly.

[0019] As a further improvement of the technical solution, the meshing gear rotates through the shaping roller and the transmission belt, the lower surface of the adjustment plate is meshed and raised and lowered with the meshing gear surface, and drives the connecting rod to move up and down on the surface of the mounting plate.

[0020] As a further improvement of the present technical solution, one side of the slider surface is connected to the connecting rod, and one side of the slider surface is connected to the upper pressing plate and the middle pressing plate, thereby driving the upper pressing plate and the middle pressing plate to lift and press on the surface of the middle conveyor platform and the upper conveyor platform.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The production method of the multi-layered structured environmentally friendly PET co-extruded board is that the PET core material is a food-grade PET polymer environmentally friendly material. There is no such material used as decorative panels on the market for the time being. The overall bonding is to melt the PET body, does not contain any glue components, and the same product and material are all PET, which can be directly recycled, eliminating the felling of wood and protecting nature. At the same time, the surface material can be made of any density, thickness and color, and various textures can be pressed. The product is environmentally friendly, and the finished product has no harmful gas emissions. The environmental protection level is 10 times higher than ENF. This product can be used in the entire scene of home decoration and industrial decoration, including walls, ceilings, floors, cabinets, doors, etc.; building exterior walls, cold chain vans, RVs, movable homes, yachts, building templates, etc.

[0023] 2. The production method of the multi-layered environmentally friendly PET co-extruded board is as follows: the upper decorative layer is pulled to the lower surface of the upper pressing plate by the upper unwinding roller, and the lower unwinding roller extends the lower decorative layer from the opened positioning groove to the surface of the lower conveying table. The upper pressing plate and the middle pressing plate can be provided to perform preliminary pressing operation on the upper decorative layer and the PET core material transmitted on the surface of the middle conveying table and the upper conveying table under the rotation of the shaping roller and the conveying belt, so as to facilitate the subsequent pressing with the surface of the shaping roller, ensure the product thickness and surface flatness, and improve the stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the structure of the extrusion equipment of the present invention;

[0025] Figure 2 It is a schematic diagram of the connection structure of the unwinding mechanism and the pressing mechanism of the present invention;

[0026] Figure 3 It is a schematic diagram of the connection structure of the upper single screw conveying rod, the double screw conveying rod and the lower single screw conveying rod of the present invention;

[0027] Figure 4 for Figure 3 A schematic diagram of the enlarged structure at A in the middle;

[0028] Figure 5 It is a schematic diagram of the connection structure of the upper extrusion slot, the middle extrusion slot, the lower extrusion slot and the lower conveying platform, the upper conveying platform and the middle conveying platform of the present invention;

[0029] Figure 6 It is a schematic diagram of the connection structure of the unwinding roller, the rotating gear and the transmission belt of the present invention;

[0030] Figure 7 for Figure 6 A schematic diagram of the enlarged structure at B in the middle;

[0031] Figure 8 It is a schematic diagram of the product of the present invention.

[0032] The meaning of each number in the figure is:

[0033] 100, extrusion equipment; 101, housing; 102, fixed base; 103, feed inlet 1; 104, feed inlet 2; 105, feed inlet 3;

[0034] 200, extrusion mechanism; 201, driving motor 1; 202, driving gear; 203, conveyor belt; 204, upper single screw conveyor rod; 205, double screw conveyor rod; 206, lower single screw conveyor rod; 207, upper extrusion slot; 208, middle extrusion slot; 209, lower extrusion slot;

[0035] 300, unwinding mechanism; 301, driving motor 2; 302, unwinding roller; 303, rotating gear; 304, transmission belt 1;

[0036] 400, pressing mechanism; 401, lower conveying platform; 402, shaping roller; 403, upper conveying platform; 404, upper pressing plate; 405, middle conveying platform; 406, middle pressing plate; 407, mounting plate; 408, slider; 409, elastic spring; 410, connecting rod; 411, adjusting plate; 412, meshing gear; 413, transmission belt 2; 414, positioning groove. DETAILED DESCRIPTION

[0037] The following will be combined with the accompanying drawings in the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] Example

[0039] See also Figure 1-Figure 8 As shown, the purpose of this embodiment is to provide a method for producing a multi-layered environmentally friendly PET co-extruded board, including a decorative layer, a PET core material, a shaping roller 402, an extrusion device 100, an extrusion mechanism 200, an unwinding mechanism 300 and a pressing mechanism 400, and the specific steps are as follows:

[0040] S1. PET core material is extruded by twin-screw + single-screw splicing extruder, with PET polyester particles as the main formula, plus nucleating agent, chain extender, antioxidant, and PET core material is food-grade PET polymer environmentally friendly material;

[0041] S2. The upper and lower surface decorative layers are also made of PET core material, which is extruded by a twin-screw + single-screw splicing extruder. PET polyester particles are used as the main formula, and nucleating agents, chain extenders, and antioxidants are added. The upper and lower surface decorative layers prepared in advance are placed on the upper and lower surfaces of the PET sheet coming out of the foaming port through the unwinding mechanism 300;

[0042] S3, the finished product after preliminary merging can be bonded to various decorative layers on the surface as a whole because the PET core material foamed out from the inside is still in a molten state, and then pressed by the pressure of the shaping roller 402 to ensure the thickness and surface flatness of the product;

[0043] S4. After forming, the product will go through the process of trimming, applying protective film, and slitting into the length and width required by the customer to form the final product;

[0044] S5. After pressure relief, place the product in a designated constant temperature and humidity room for curing to ensure the quality of the final product.

[0045] The PET core material is a food-grade PET polymer environmentally friendly material. There is currently no such material used as decorative panels on the market. It adopts a food-grade PET physical foaming process, which can be customized according to customer needs to produce products with different densities or functionalities (flame retardant, negative oxygen ions). The overall bonding is melted PET body and does not contain any glue components. The same product and material are all PET, which can be directly recycled, eliminating the felling of wood and protecting nature. At the same time, the surface material can be made of any density, thickness and color, and various textures can be pressed. The product is environmentally friendly, and the finished product has no harmful gas emissions. The environmental protection level is 10 times higher than ENF. This product can be used in the entire scene of home decoration and industrial decoration, including walls, ceilings, floors, cabinets, doors, etc.; building exterior walls, cold chain vans, RVs, movable homes, yachts, building templates, etc.

[0046] according to Figure 4-Figure 5 and Figure 8 As shown, considering the need to realize the pressing effect of the pressing mechanism 400, in this embodiment, the pressing mechanism 400 includes a lower conveying platform 401, a shaping roller 402 is installed on one side of the upper surface of the lower conveying platform 401, a conveying belt 2 413 is connected to the surface of the shaping roller 402, a meshing gear 412 is connected to one side of the surface of the conveying belt 2 413, a middle conveying platform 405 and an upper conveying platform 403 are installed on the upper surface of the lower conveying platform 401, mounting plates 407 are installed on both sides of the upper surfaces of the middle conveying platform 405 and the upper conveying platform 403, and a An elastic spring 409, one side of the surface of the elastic spring 409 is connected to a slider 408, one side of the surface of the slider 408 is connected to a connecting rod 410, an adjustment plate 411 is sleeved at the center of the outer surface of the connecting rod 410, the back surface of the slider 408 is connected to the upper pressing plate 404 and the middle pressing plate 406, a positioning groove 414 is provided on one side of the surface of the lower conveying platform 401, and the lower surface of the adjustment plate 411 is in rotational meshing contact with the outer surface of the meshing gear 412, so that the upper pressing plate 404 and the middle pressing plate 406 are adjusted up and down on the upper surfaces of the middle conveying platform 405 and the upper conveying platform 403;

[0047] Furthermore, after the PET core material after extrusion and foaming is extruded from the middle conveying platform 405, the shaping roller 402 is rotated to drive the second conveying belt 413 and the meshing gear 412 to rotate, so that the meshing gear 412 is meshed with the surface of the adjustment plate 411 through the meshing teeth, and then the connecting rod 410 drives the slider 408 to move up and down on the surface of the mounting plate 407 under the elastic force of the elastic spring 409, and drives the middle pressing plate 406 to move up and down synchronously on the surface of the middle conveying platform 405;

[0048] The improvement is that the middle pressing plate 406 can preliminarily press the PET core material transmitted on the surface of the middle conveying platform 405 and the upper decorative layer transmitted on the upper surface of the unwinding mechanism 300, making the fit smoother and facilitating the subsequent tight pressing by the shaping roller 402.

[0049] according to Figure 1 As shown, considering the need to realize the driving effect of the extrusion device 100, in this embodiment, the extrusion device 100 includes a shell 101, a fixed base 102 is installed on the left side of the lower surface of the shell 101, and a feed port 103, a feed port 204 and a feed port 3 105 are arranged on the upper surface of the shell 101, and the feed port 103, the feed port 204 and the feed port 3 105 are connected to the inside of the extrusion mechanism 200 correspondingly;

[0050] Furthermore, the feed port 1 103, the feed port 2 104 and the feed port 3 105 can be used to perform twin-screw + single-screw splicing extrusion for the PET core material, and are connected to the surfaces of the lower conveying platform 401, the middle conveying platform 405 and the upper conveying platform 403 accordingly;

[0051] The improvement lies in: according to customer needs, the number of extruders corresponding to the number of layers of structure required will be opened. Different extruders correspond to different extrusion dies, and different masterbatches can be added to control the addition of different masterbatches to achieve multiple colors and multi-layer structures of the product.

[0052] according to Figure 3 As shown, considering the need to realize the extrusion effect of the extrusion mechanism 200, in this embodiment, the extrusion mechanism 200 includes a driving motor 201, one side of the surface of the driving motor 201 is fixedly connected to a driving gear 202, the outer surface of the driving gear 202 is meshed with a conveyor belt 203, one side of the surface of the driving gear 202 is fixedly sleeved with an upper single screw conveying rod 204, a middle double screw conveying rod 205 and a lower single screw conveying rod 206, and the outer surfaces of the upper single screw conveying rod 204, the middle double screw conveying rod 205 and the lower single screw conveying rod 206 are provided with an upper extrusion groove 207, a middle extrusion groove 208 and a lower extrusion groove 209. Groove 209, the upper single screw conveying rod 204, the middle double screw conveying rod 205 and the lower single screw conveying rod 206 are distributed in a rhombus shape inside the extrusion device 100 as a whole, and the upper single screw conveying rod 204, the middle double screw conveying rod 205 and the lower single screw conveying rod 206 are synchronously rotated through the driving gear 202 and the conveyor belt 203, and the bottom surfaces of the upper extrusion groove 207, the middle extrusion groove 208 and the lower extrusion groove 209 are all provided with opening and closing plates and sensors, the sensors are temperature sensors, and the opening and closing plates are opened and closed by the sensors on the bottom surfaces of the upper extrusion groove 207, the middle extrusion groove 208 and the lower extrusion groove 209;

[0053] Furthermore, by starting the driving motor 201, the driving gear 202 is driven to rotate. Under the transmission action of the conveyor belt 203, the upper single screw conveying rod 204, the middle double screw conveying rod 205 and the lower single screw conveying rod 206 are effectively rotated synchronously, and the temperature of the middle double screw conveying rod 205 is about 280°C-300°C, and the temperature of the upper single screw conveying rod 204 and the lower single screw conveying rod 206 is about 230°C-260°C. Through the induction of the temperature sensor, the opening and closing of the upper extrusion groove 207, the middle extrusion groove 208 and the lower extrusion groove 209 are adjusted, so that the upper extrusion groove 207, the middle extrusion groove 208 and the lower extrusion groove 209 are connected to each other;

[0054] The improvement lies in that the upper single spiral conveyor rod 204, the middle double spiral conveyor rod 205 and the lower single spiral conveyor rod 206 are spliced ​​and extruded to effectively improve the quality of the manufactured PET core material, and the temperature difference between the middle double spiral conveyor rod 205 and the upper single spiral conveyor rod 204 and the lower single spiral conveyor rod 206 is utilized, and the control function of the temperature sensor is utilized to make the entire extrusion process stable and efficient, which can meet the needs of large-scale and continuous production (Note: the model of the temperature sensor is PT100 platinum resistance temperature sensor, which is a prior art and is not described in detail).

[0055] according to Figure 2 and Figure 6 As shown, considering the need to realize the unwinding function of the unwinding mechanism 300, in this embodiment, the unwinding mechanism 300 includes a driving motor 2 301, a surface side of the driving motor 2 301 is connected to an unwinding roller 302, a surface side of the unwinding roller 302 is connected to a rotating gear 303, and the outer surface of the rotating gear 303 is connected to a transmission belt 1 304, and two unwinding rollers 302 are provided, and the two unwinding rollers 302 are symmetrically distributed at the upper and lower ends of the right side of the surface of the extrusion device 100, and the two unwinding rollers 302 are synchronously rotated through the rotating gear 303 and the transmission belt 1 304;

[0056] Furthermore, by starting the second driving motor 301, the unwinding roller 302 is rotated, and the upper decorative layer and the lower decorative layer are placed on the surface of the unwinding roller 302, the upper decorative layer is in contact with the lower surface of the upper pressing plate 404 and the middle pressing plate 406, and the surface of the lower decorative layer passes through the positioning groove 414 and fits with the surface of the lower conveying platform 401, and under the action of the rotating gear 303 and the conveying belt 1 304, the upper decorative layer and the lower decorative layer are rolled and transmitted on the surface of the unwinding roller 302;

[0057] The improvement lies in that: while the upper decorative layer is rolling and transported on the surface of the unwinding roller 302, it is initially pressed and bonded to the PET core material transported on the surfaces of the middle conveyor platform 405 and the upper conveyor platform 403 through the pressing effect of the upper pressing plate 404 and the middle pressing plate 406, and at the same time, the surface of the lower decorative layer can be initially bonded to the surface of the PET core material transported on the surface of the lower conveyor platform 401, and the initially bonded upper decorative layer and PET core material on the surface of the middle conveyor platform 405 are dropped to the initially bonded lower decorative layer and PET core material on the surface of the lower conveyor platform 401, and are contacted and bonded, and finally are pressed together under the pressure of the shaping roller 402 to obtain a molded product.

[0058] In summary, the PET core material can be introduced into the upper extrusion groove 207, the middle extrusion groove 208 and the lower extrusion groove 209 through the set feed port 1 103, the feed port 2 104 and the feed port 3 105, and the single spiral + double spiral extrusion operation is performed on the PET core material. The upper unwinding roller 302 pulls the upper decorative layer to the lower surface position of the upper pressing plate 404, and the lower unwinding roller 302 extends the lower decorative layer from the opened positioning groove 414 to the surface of the lower conveying platform 401. The set upper pressing plate 404 and the middle pressing plate 406 can perform preliminary pressing operation on the upper decorative layer and the PET core material transmitted on the surface of the middle conveying platform 405 and the upper conveying platform 403 under the rotation of the shaping roller 402 and the conveyor belt 2 413, so as to facilitate the subsequent pressing with the surface of the shaping roller 402, ensure the product thickness and surface flatness, and improve stability.

[0059] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for producing a multi-layered environmentally friendly PET co-extruded board, characterized in that: The invention comprises a decorative layer, a PET core material, a shaping roller (402), an extrusion device (100), an extrusion mechanism (200), an unwinding mechanism (300) and a pressing mechanism (400), and the specific steps are as follows: S1. The PET core material is extruded by a twin-screw + single-screw splicing extruder, with PET polyester particles as the main formula, and added with nucleating agent, chain extender, antioxidant, and the PET core material is a food-grade PET polymer environmentally friendly material; S2, the upper and lower surface decorative layers are also made of PET core material, which is extruded by a twin-screw + single-screw splicing extruder, with PET polyester particles as the main formula, and added with nucleating agent, chain extender, and antioxidant, and are placed on the upper and lower surfaces of the PET sheet coming out of the foaming port through the unwinding mechanism (300); S3, the finished product after preliminary merging can be bonded to the various decorative layers on the surface as a whole because the PET core material foamed inside is still in a molten state, and then pressed by the pressure of the shaping roller (402) to ensure the thickness and surface flatness of the product; S4. After forming, the product will go through the process of trimming, applying protective film, and slitting into the length and width required by the customer to form the final product; S5. After the pressure relief is completed, the product is placed in a designated constant temperature and humidity room for curing to ensure the quality of the final product; The pressing mechanism (400) comprises a lower conveying platform (401), a shaping roller (402) is installed on one side of the upper surface of the lower conveying platform (401), a second conveying belt (413) is connected to the surface of the shaping roller (402), a meshing gear (412) is connected to one side of the surface of the second conveying belt (413), a middle conveying platform (405) and an upper conveying platform (403) are installed on the upper surface of the lower conveying platform (401), mounting plates (407) are installed on both sides of the upper surfaces of the middle conveying platform (405) and the upper conveying platform (403), an elastic spring (409) is installed at the center of the surface of the mounting plate (407), and the elastic spring (409) A slider (408) is connected to one side of the surface, a connecting rod (410) is connected to one side of the surface of the slider (408), an adjustment plate (411) is sleeved at the center position of the outer surface of the connecting rod (410), an upper pressing plate (404) and a middle pressing plate (406) are connected to the back surface of the slider (408), a positioning groove (414) is provided on one side of the surface of the lower conveying platform (401), and the lower surface of the adjustment plate (411) is rotatably engaged with the outer surface of the meshing gear (412), so that the upper pressing plate (404) and the middle pressing plate (406) can be raised and lowered and adjusted on the upper surfaces of the middle conveying platform (405) and the upper conveying platform (403).

2. The method for producing the multi-layered environmentally friendly PET co-extruded board according to claim 1, characterized in that: The extrusion device (100) comprises a shell (101), a fixed base (102) is installed on the left side of the lower surface of the shell (101), and a feed port 1 (103), a feed port 2 (104) and a feed port 3 (105) are arranged on the upper surface of the shell (101), and the feed port 1 (103), the feed port 2 (104) and the feed port 3 (105) are connected to the inside of the extrusion mechanism (200) correspondingly.

3. The method for producing the multi-layered environmentally friendly PET co-extruded board according to claim 1, characterized in that: The extrusion mechanism (200) comprises a driving motor (201), one side of the surface of the driving motor (201) is fixedly connected to a driving gear (202), the outer surface of the driving gear (202) is meshed with a conveyor belt (203), one side of the surface of the driving gear (202) is fixedly sleeved with an upper single screw conveying rod (204), a middle double screw conveying rod (205) and a lower single screw conveying rod (206), the upper single screw conveying rod (204), the middle double screw conveying rod (205) and the lower single screw conveying rod (206) An upper extrusion groove (207), a middle extrusion groove (208) and a lower extrusion groove (209) are arranged on the outer surface of the conveying rod (206); the upper single screw conveying rod (204), the middle double screw conveying rod (205) and the lower single screw conveying rod (206) are distributed in a rhombus shape inside the extrusion device (100) as a whole; and the upper single screw conveying rod (204), the middle double screw conveying rod (205) and the lower single screw conveying rod (206) rotate synchronously through the driving gear (202) and the conveyor belt (203).

4. The method for producing the multi-layered environmentally friendly PET co-extruded board according to claim 3, characterized in that: The unwinding mechanism (300) comprises a second driving motor (301), a second driving motor (301) having a second unwinding roller (302) connected to one side of its surface, a rotating gear (303) connected to one side of its surface, a transmission belt (304) connected to the outer surface of the rotating gear (303), and a second unwinding roller (302) being provided at two locations, the two unwinding rollers (302) being symmetrically distributed at the upper and lower ends of the right side of the surface of the extrusion device (100), and the two unwinding rollers (302) are synchronously rotated through the rotating gear (303) and the transmission belt (304).

5. The method for producing the multi-layered environmentally friendly PET co-extruded board according to claim 3, characterized in that: The bottom surfaces of the upper extrusion groove (207), the middle extrusion groove (208) and the lower extrusion groove (209) are all provided with opening and closing plates and sensors, wherein the sensors are temperature sensors, and the opening and closing plates are adjusted by the sensors on the bottom surfaces of the upper extrusion groove (207), the middle extrusion groove (208) and the lower extrusion groove (209).

6. The method for producing the multi-layered environmentally friendly PET co-extruded board according to claim 3, characterized in that: One side of the surface of the lower conveying platform (401), the middle conveying platform (405) and the upper conveying platform (403) is parallel to and correspondingly connected to the surface of the upper extrusion groove (207), the middle extrusion groove (208) and the lower extrusion groove (209), and the lower surface of the middle conveying platform (405) and the upper conveying platform (403) is correspondingly connected to the surface of the lower conveying platform (401).

7. The method for producing the multi-layered environmentally friendly PET co-extruded board according to claim 4, characterized in that: The upper and lower sides of the two unwinding rollers (302) are correspondingly connected to the upper pressing plate (404) and the positioning groove (414); the lower unwinding roller (302) passes through the positioning groove (414) and fits the surface of the lower conveying platform (401), and is correspondingly connected to one side of the surface of the lower extrusion groove (209).

8. The method for producing the multi-layered environmentally friendly PET co-extruded board according to claim 1, characterized in that: The meshing gear (412) is rotated by the shaping roller (402) and the second transmission belt (413), and the lower surface of the adjustment plate (411) is in meshing and lifting contact with the surface of the meshing gear (412), thereby driving the connecting rod (410) to move up and down on the surface of the mounting plate (407).

9. The method for producing the multi-layered environmentally friendly PET co-extruded board according to claim 8, characterized in that: One side of the surface of the slider (408) is connected to the connecting rod (410) in correspondence, and one side of the surface of the slider (408) is connected to the upper pressing plate (404) and the middle pressing plate (406) in correspondence, thereby driving the upper pressing plate (404) and the middle pressing plate (406) to rise, fall and press on the surface of the middle conveying platform (405) and the upper conveying platform (403).

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