Production line for flame-retardant sheets made of waste plastics and temperature control method of production line

Abstract

The invention relates to the technical field of waste plastic recycling, in particular to a production line for a flame-retardant sheet made of waste plastic, a temperature control method of the production line, the production line and a middle-layer extrusion assembly, and the production line comprises a middle-layer extruder, a layered extrusion port formed in the middle-layer extruder and a second connecting pipe arranged on the layered extrusion port; the inner-layer extrusion assembly comprises an inner-layer extruder and a middle extrusion port formed in the inner-layer extruder; the middle extrusion port, the first connecting pipe and the second connecting pipe are all connected with the combined extrusion machine head, and an extrusion component and a temperature control assembly are arranged on the combined extrusion machine head. According to the PP flame-retardant sheet production line designed by the invention, differential temperature gradients can be set according to different melting requirements of PP flame-retardant raw materials of a surface layer, a middle layer and an inner layer, so that the raw materials are prevented from being degraded or insufficiently melted, and the melt quality of each layer is ensured.

Description

Technical Field

[0001] This invention relates to the field of waste plastic recycling technology, and in particular to a production line for PP flame-retardant sheets made from waste plastics and its temperature control method. Background Technology

[0003] Existing technologies for converting waste plastics into flame-retardant sheets still suffer from multiple technical challenges, resulting in poor product quality stability, low production efficiency, and insufficient environmental compliance. This makes it difficult to meet market demand for high-performance recycled flame-retardant sheets. Specific problems include:

[0004] Extrusion molding is one of the important methods for molding thermoplastic plastics. In the extrusion molding process, the extruder passes the heated plastic raw material, which is in a viscous state, through the extrusion mold to form a continuous body with a cross section similar to the shape of the mold. After cooling and shaping, it is finally cut to obtain the desired plastic product.

[0005] In the existing technology, the pressure is relatively high when the co-extruder injects raw material into the die, which can easily lead to material leakage and affect the quality of the product. In order to reduce the pressure when the co-extruder injects raw material, the co-extruder is usually placed on the side of the main extruder and the raw material is injected into the die from the side surface of the die.

[0006] In existing methods of extruding PP flame-retardant sheets, it is difficult to immediately cut the raw material after extrusion, making it difficult to cut the flame-retardant sheet into a specific shape immediately after production. Summary of the Invention

[0007] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0008] In view of the problems existing in the above-mentioned flame-retardant sheet production lines, the present invention is proposed.

[0009] Therefore, the purpose of this invention is to provide a production line for flame-retardant sheets made from waste plastics and a method for controlling the temperature thereon.

[0010] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0011] In a first aspect, the present invention provides a production line for flame-retardant sheets made from waste plastics, comprising: a main frame; a surface extrusion assembly including a surface extruder, an extrusion port disposed on the surface extruder, and a first connecting pipe disposed on the extrusion port; an intermediate layer extrusion assembly including an intermediate layer extruder, a layered extrusion port disposed on the intermediate layer extruder, and a second connecting pipe disposed on the layered extrusion port; an inner layer extrusion assembly including an inner layer extruder and an intermediate extrusion port disposed on the inner layer extruder; a combined extruder head, wherein the intermediate extrusion port, the first connecting pipe, and the second connecting pipe are all connected to the combined extruder head, and the combined extruder head is provided with an extrusion component; a temperature control assembly including a surface extruder temperature control structure, an intermediate layer extruder temperature control structure, and an inner layer extruder temperature control structure; and a conveying and cutting assembly disposed near the extrusion component.

[0012] As a preferred embodiment of the flame-retardant sheet production line made from waste plastics according to the present invention, wherein: a first pipe cavity is provided in the combined extruder head, the first pipe cavity is connected to a first connecting pipe, a second pipe cavity is provided in the combined extruder head, the first pipe cavity is disposed outside the second pipe cavity, the second pipe cavity is connected to a second connecting pipe, a co-extrusion cavity is formed in the intermediate extrusion port, and both the first pipe cavity and the second pipe cavity are connected to the co-extrusion cavity.

[0013] As a preferred embodiment of the flame-retardant sheet production line made from waste plastics according to the present invention, the extrusion component includes a connecting plate connected to the combined extruder head and a retention groove opened on the connecting plate. A retaining edge is provided in the retention groove. A clamping member is provided in the retaining edge. The clamping member includes a pressing plate provided in the retaining edge. A micro motor is provided in the retaining edge. A cam is provided on the micro motor. The edge of the cam abuts against the upper edge of the pressing plate. An elastic member is provided between the pressing plate and the retaining edge.

[0014] As a preferred embodiment of the flame-retardant sheet production line made from waste plastics according to the present invention, a roller frame is provided on the main frame, and guide rollers are provided on the roller frame. There are two guide rollers, and an extrusion channel is formed between the two guide rollers. A receiving frame is provided on the main frame near the roller frame, and the conveying and cutting assembly is provided on the receiving frame.

[0015] As a preferred embodiment of the flame-retardant sheet production line made from waste plastics according to the present invention, the conveying and cutting assembly includes a first receiving plate and a second receiving plate slidably connected to a receiving frame, a first transverse groove and a second transverse groove formed on the inner wall of the receiving frame, an inclined groove provided between the first transverse groove and the second transverse groove, a pull rod provided on the second receiving plate, a wheel provided at the lower end of the pull rod, the wheel cooperating with the first transverse groove, the second transverse groove and the inclined groove, a conveying component provided inside the receiving frame, and a cutting component provided on the bottom surface of the first receiving plate.

[0016] As a preferred embodiment of the flame-retardant sheet production line made from waste plastics according to the present invention, the cutting component includes a plurality of baffles disposed at the lower end of the first receiving plate, a suction cup plate disposed at the lower end of the first receiving plate, and a plurality of spray tubes disposed on the suction cup plate. The baffles include a plurality of triangular ring plates of increasing size that are nested together. Each of the triangular ring plates is pushed by a cylinder, and the suction cup plate is disposed between the plurality of triangular ring plates.

[0017] As a preferred embodiment of the flame-retardant sheet production line made from waste plastics according to the present invention, the lower end of the first receiving plate is detachably bolted to a movable guide rail, a push block is slidably connected on the movable guide rail, a lead screw is provided on the push block, a drive motor for driving the lead screw to rotate is provided at the end of the movable guide rail, and the cylinder is provided on the push block.

[0018] The lower end of the first receiving plate is provided with a baffle for installing the baffle. The baffle is detachably connected to a triangular ring plate, and an entry hole is provided on the baffle corresponding to the triangular ring plate.

[0019] As a preferred embodiment of the flame-retardant sheet production line made from waste plastics according to the present invention, the triangular ring plate is composed of three sets of cutting sheet groups that are hinged to each other. Each cutting sheet group includes several cutting sheet plates that are hinged to each other in sequence. The cutting sheet plates are hinged to the support. One end of the cutting sheet plate is provided with a cutting blade, and the other end is provided with a cleaning roller.

[0020] Secondly, this invention provides a temperature control method for a production line of flame-retardant sheets made from waste plastics, comprising,

[0021] Based on the melting characteristics of PP flame-retardant raw materials, the gradient temperature for raw material melting and extrusion is set;

[0022] The melt temperature threshold in the first connecting pipe, the second connecting pipe, and the intermediate extrusion port is set to 95% of the temperature of the homogenization zone of the corresponding extruder. When the sensor detects that the temperature of any one of the components in the first connecting pipe, the second connecting pipe, and the intermediate extrusion port is lower than the threshold, the temperature controller of the corresponding extruder automatically starts the heating belt, and the power of the heating belt is dynamically adjusted according to the temperature difference.

[0023] Perform zoned temperature matching control within the combined extruder head;

[0024] Perform fine-tuning control of the extrusion molding end temperature.

[0025] The beneficial effects of this invention are as follows: Differentiated temperature gradients are set for the different melting requirements of the surface, middle, and inner layers of PP flame-retardant raw materials to avoid raw material degradation or insufficient melting and ensure the quality of each layer of melt; by using heat insulation in the connecting pipe and zoned temperature control in the die head, temperature loss during melt transportation is reduced, allowing the three layers of melt to transition smoothly in temperature within the co-extrusion cavity and improving interlayer bonding strength; temperature fine-tuning at the extrusion molding end solves the problem of sheet edge warping, while closed-loop control ensures minimal temperature fluctuations. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0027] Figure 1 This is a schematic diagram of the overall structure of the flame-retardant sheet production line made from waste plastics according to the present invention.

[0028] Figure 2 This is a side view schematic diagram of the flame-retardant sheet production line made from waste plastics according to the present invention.

[0029] Figure 3 This is a schematic diagram of the co-extrusion section of the flame-retardant sheet production line made from waste plastics according to the present invention.

[0030] Figure 4 This is a cross-sectional schematic diagram of the overall structure of the flame-retardant sheet production line made from waste plastics according to the present invention.

[0031] Figure 5 This is a schematic diagram of the connecting plate structure of the flame-retardant sheet production line made from waste plastics according to the present invention.

[0032] Figure 6 This is a schematic diagram of the first and second receiving plates of the conveying and cutting assembly of the flame-retardant sheet production line made from waste plastics according to the present invention.

[0033] Figure 7 This is a schematic diagram of the conveying and cutting assembly of the flame-retardant sheet production line made from waste plastics according to the present invention.

[0034] Figure 8 This is a schematic diagram of the cutting component of the flame-retardant sheet production line made from waste plastics according to the present invention.

[0035] Figure 9 This is a schematic diagram of the cutting plate of the flame-retardant sheet production line made from waste plastics according to the present invention.

[0036] Explanation of reference numerals in the attached drawings: 1001, Main frame; 100, Surface extrusion assembly; 101, Surface extruder; 102, Extrusion port; 103, First connecting pipe; 200, Intermediate layer extrusion assembly; 201, Intermediate layer extruder; 202, Layered extrusion port; 203, Second connecting pipe; 204, Inner layer extrusion assembly; 2041, Inner layer extruder; 2042, Intermediate extrusion port; 205, Combined extruder head; 206, Temperature control assembly; 2061, Surface extruder temperature control structure; 2062, Intermediate layer extruder temperature control structure; 2063, Inner layer extruder temperature control structure; 2051, First pipe cavity; 2052, Second pipe cavity; 2053, Co-extrusion cavity; 300, Extrusion component; 301, Connecting plate; 302, Retention groove; 303. Edge clamp; 3041, pressing plate; 3042, micro motor; 3043, cam; 3044, elastic element; 1002, roller frame; 1003, guide roller; 1004, receiving frame; 400, conveying and cutting assembly; 401, first receiving plate; 402, second receiving plate; 403, first transverse groove; 404, second transverse groove; 405, pull rod; 4051, wheel; 406, conveyor; 4061, rotating wheel; 4062, conveyor belt; 4063, slider; 500, cutting component; 502, suction cup plate; 503, spray pipe; 5011, triangular ring plate; 5001, cylinder; 504, moving guide rail; 505, push block; 506, lead screw; 507, baffle; 5012, cutting plate; 5013, slice; 5014, cleaning roller. Detailed Implementation

[0037] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0038] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0039] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0040] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0041] Example 1

[0042] Reference Figures 1-9 The first embodiment of the present invention provides a flame-retardant sheet production line made of waste plastic, including a main frame 1001, which is the main support structure of the entire production line and adopts a frame form.

[0043] Furthermore, the present invention also includes a surface extrusion assembly 100. In this embodiment, the surface extrusion assembly 100 includes a surface extruder 101, an extrusion port 102 disposed on the surface extruder 101, and a first connecting pipe 103 disposed on the extrusion port 102. The surface extruder 101 is mainly used to provide the outermost layer material of the flame-retardant sheet. The surface extruder 101 is an existing twin-screw extruder. The extrusion port 102 is connected to the surface extruder 101 by means of a flange structure. The first connecting pipe 103 on the extrusion port 102 is also connected by means of a flange structure, and a sealing film is provided at the connection.

[0044] Furthermore, the present invention also includes an intermediate layer extrusion assembly 200. In this embodiment, the intermediate layer extrusion assembly 200 includes an intermediate layer extruder 201, a layer extrusion port 202 disposed on the intermediate layer extruder 201, and a second connecting pipe 203 disposed on the layer extrusion port 202. The intermediate layer extruder 201 is mainly used to provide the intermediate layer material of the flame retardant sheet. The intermediate layer extruder 201 is an existing twin-screw extruder. The second connecting pipe 203 runs parallel to the first connecting pipe 103 and is also provided with a docking structure at its end for subsequent communication with the combined extruder head 205 to realize the transportation of the intermediate layer melt.

[0045] Furthermore, the present invention also includes an inner layer extrusion assembly 204. In this embodiment, the inner layer extrusion assembly 204 includes an inner layer extruder 2041 and an intermediate extrusion port 2042 disposed on the inner layer extruder 2041. The inner layer extruder 2041 is disposed in the central region of the main frame 1001, and the intermediate extrusion port 2042 at its end is directly aligned with the combined extruder head 205. The inner wall of the port is smoothed to reduce the flow resistance of the inner layer melt and ensure smooth melt delivery.

[0046] Furthermore, the present invention also includes a combined extruder head 205, with an intermediate extrusion port 2042, a first connecting pipe 103 and a second connecting pipe 203 all connected to the intermediate extrusion port 2042, and an extrusion component 300 provided on the combined extruder head 205.

[0047] Furthermore, it also includes a temperature control component 206, which includes a surface extruder temperature control structure 2061: on the barrel of the surface extruder 101, heating modules and insulation layers are installed in sections along the screw axis. The barrel is divided into three temperature control zones from the feed port to the extrusion port 102. Each temperature control zone is wound with two sets of stainless steel heating coils, each with a power of 500W. The heating coils are wrapped with a ceramic fiber insulation layer. A PT100 platinum resistance temperature sensor is embedded in the inner wall of the barrel in each temperature control zone. The sensor signal is connected to the surface extruder 101's dedicated intelligent temperature controller, forming an independent temperature control loop of "heating-insulation-detection".

[0048] Furthermore, the temperature control component 206 includes an intermediate layer extruder temperature control structure 2062: it is also divided into 3 temperature control zones with heating coils, insulation layers and temperature sensors, and equipped with independent intelligent temperature controllers, but the heating coil power is adjusted to 600W, and the temperature controller parameters can be set independently to ensure that it does not interfere with the surface temperature control.

[0049] Furthermore, the temperature control component 206 includes a middle inner layer extruder temperature control structure 2063: the barrel is divided into 3 temperature control zones, the heating coil power is 400W, and the specifications of the remaining heating coils, insulation layer, temperature sensor and temperature controller are the same as those of the surface layer, and they operate independently to match the characteristics of the inner layer raw materials.

[0050] On the outer wall of the combined extruder head 205, three independent heating zones are divided into “first pipe cavity 2051 (surface melt channel), second pipe cavity 2052 (intermediate melt channel), and co-extrusion cavity 2053 (three-layer fusion zone)”. Flexible silicone heating pads are attached to each heating zone, covering the outer wall area of ​​the corresponding cavity. Adjacent heating zones are isolated with heat insulation cotton to prevent heat crosstalk. A PT100 temperature sensor is embedded in the inner wall of the die head in each heating zone. The sensor probe is close to the melt flow path to ensure that the detected temperature is close to the actual melt temperature.

[0051] Collaborative temperature controller: Sensor signals from the three heating zones are connected to the same collaborative temperature controller. The controller can preset the target temperature for each heating zone and interact with the intelligent temperature controllers of each extruder to achieve temperature coordination.

[0052] Furthermore, the present invention also includes a conveying and cutting assembly 400, which is disposed near the extrusion member 300.

[0053] Furthermore, a first pipe cavity 2051 is provided inside the combined extruder head 205, and the first pipe cavity 2051 is connected to the first connecting pipe 103. A second pipe cavity 2052 is provided inside the extruder head, and the first pipe cavity 2051 is located outside the second pipe cavity 2052. The second pipe cavity 2052 is connected to the second connecting pipe 203. A co-extrusion cavity 2053 is formed inside the intermediate extrusion port 2042. Both the first pipe cavity 2051 and the second pipe cavity 2052 are connected to the co-extrusion cavity 2053.

[0054] Preferably, the first pipe cavity 2051 is connected to the first connecting pipe 103 for conveying the surface melt; the first pipe cavity 2051 surrounds the second pipe cavity 2052 and is connected to the second connecting pipe 203 for conveying the intermediate layer melt; the first pipe cavity 2051 and the second pipe cavity 2052 are both connected to the co-extrusion cavity 2053 through flow channels, so that the three layers of melt can be layered and merged in the co-extrusion cavity 2053 as "inner layer-intermediate layer-surface layer".

[0055] Preferably, an extrusion component 300 is installed on the combined extruder head 205, and a connecting plate 301 of the extrusion component 300 is fixed to the combined extruder head 205. A retention groove 302 is opened on the connecting plate 301, and a clamping component is installed in the retaining edge 303 in the retention groove 302.

[0056] In this embodiment, the extrusion component 300 includes a connecting plate 301 connected to the combined extruder head 205, a storage groove 302 formed on the connecting plate 301, a retaining edge 303 provided in the storage groove 302, and a clamping member provided in the retaining edge 303.

[0057] Furthermore, in this embodiment, the clamping member includes a pressing plate 3041 disposed within the clamping edge 303, a micro motor 3042 disposed within the clamping edge 303, a cam 3043 disposed on the micro motor 3042, the edge of the cam 3043 abutting against the upper edge of the pressing plate 3041, and an elastic element 3044 disposed between the pressing plate 3041 and the clamping edge 303. In this embodiment, the elastic element 3044 is a spring. The above structure constitutes a clamping structure of "cam 3043 driving - elastic reset" for stabilizing the extrusion shape of the sheet.

[0058] Preferably, the connecting plate 301 is arc-shaped and there are several of them. The several connecting plates 301 form an arc-shaped structure, and the pressing plate 3041 is also arc-shaped. When the several micro motors 3042 are started, they have two modes: 1. synchronous rotation, which can simultaneously control the sliding of several pressing plates 3041; 2. distributed control of several micro motors 3042, which can change the frequency of the flame-retardant sheet being squeezed by the pressing plate 3041.

[0059] Furthermore, a roller frame 1002 is provided on the main frame 1001, and a guide roller 1003 is provided on the roller frame 1002. There are two guide rollers 1003, and the two guide rollers 1003 form an extrusion channel between them. A receiving frame 1004 is provided on the main frame 1001 near the roller frame 1002, and the conveying and cutting assembly 400 is provided on the receiving frame 1004.

[0060] Preferably, one of the roller holders 1002 is located away from the combined extruder head 205, and a guide roller 1003 is also provided on this roller holder 1002.

[0061] Furthermore, in this embodiment, the conveying and cutting assembly 400 includes a first receiving plate 401 and a second receiving plate 402 slidably connected to the receiving frame 1004, and a longitudinal plate opened in the receiving frame 1004. A first transverse groove 403 and a second transverse groove 404 are opened on the longitudinal plate. The first transverse groove 403 and the second transverse groove 404 are opened in the horizontal direction. An inclined groove is provided between the first transverse groove 403 and the second transverse groove 404. Two inclined grooves are provided. Two first transverse grooves 403 are provided, and their height is higher than that of the second transverse groove 404. The inclined groove connects the two first transverse grooves 403 and the second transverse groove 404. A wheel 4051 is provided on the side wall of the second receiving plate 402. The wheel 4051 cooperates with the first transverse groove 403, the second transverse groove 404 and the inclined groove. A conveying component 406 is provided in the receiving frame 1004. A cutting component 500 is provided on the bottom surface of the first receiving plate 401.

[0062] In this embodiment, the conveyor 406 includes a plurality of rotating wheels 4061 disposed on the side wall of the receiving frame 1004, a conveyor belt 4062 disposed outside the plurality of rotating wheels 4061, and sliders 4063 disposed on the conveyor belt 4062. The conveyor belt 4062 is configured as a rectangular loop, the rotating wheels 4061 are disposed at the four corners of the conveyor belt 4062, and the sliders 4063 are disposed at two parallel positions above and below the conveyor belt 4062. A motor is disposed on one of the rotating wheels 4061. When the motor drives the rotating wheel 4061 to rotate, it drives the conveyor belt 4062 to rotate, thereby causing the two sliders 4063 to move in opposite directions, and thus causing the first receiving plate 401 and the second receiving plate 402 to move in opposite directions.

[0063] Preferably, a plurality of longitudinally arranged telescopic rods are provided on the slider 4063 corresponding to the second receiving plate 402. The telescopic rods are connected to the second receiving plate 402, and a pull rod 405 extends out from the lower end of the second receiving plate 402. A wheel 4051 is provided at the lower end of the pull rod 405.

[0064] Preferably, a bent plate extends from the second receiving plate 402. The bent plate is used to restrict the flame-retardant sheet. The cross-sectional shape of the bent plate is an inverted "L" shape. Two bent plates are provided and are arranged opposite to each other.

[0065] Furthermore, in this embodiment, the cutting component 500 includes a plurality of stops disposed at the lower end of the first receiving plate 401, a suction cup plate 502 disposed at the lower end of the first receiving plate 401, and a plurality of spray pipes 503 disposed on the suction cup plate 502. The spray pipes 503 are used to spray an outer layer film onto the surface of the manufactured flame retardant material. The stops include a plurality of triangular ring plates 5011 of progressively larger size, each of which is pushed by a cylinder 5001. The suction cup plate 502 is disposed between the plurality of triangular ring plates 5011.

[0066] Preferably, each triangular ring plate 5011 has a different size, but each triangular ring plate 5011 is formed into a triangle by being surrounded by an alloy iron plate.

[0067] Furthermore, a movable guide rail 504 is provided at the lower end of the first receiving plate 401, a push block 505 is slidably connected on the movable guide rail 504, a lead screw 506 is provided on the push block 505, a drive motor for driving the lead screw 506 to rotate is provided at the end of the movable guide rail 504, and the cylinder 5001 is bolted to the push block 505.

[0068] Preferably, the movable guide rail 504 is detachable, so that the operator can remove the movable guide rail 504 and the cylinder 5001 simultaneously, and then install them at different positions of the triangular ring plates 5011 so as to press down different triangular ring plates 5011.

[0069] Furthermore, a number of mounting grooves for installing the spray pipe 503 are provided on the suction plate 502, and an isolation layer is coated on the inner wall of the triangular ring plate 5011.

[0070] Preferably, a gripping plate is provided on the output shaft of cylinder 5001, which is used to grip the triangular ring plate 5011.

[0071] Preferably, a baffle 507 is provided at the lower end of the first receiving plate 401, and several triangular ring plates 5011 are detachably connected to the baffle 507. Several entry holes for the cylinder 5001 shaft of the cylinder 5001 are opened on the baffle 507, and each entry hole corresponds to a triangular ring plate 5011.

[0072] Preferably, the triangular ring plate 5011 consists of three sets of mutually hinged cutting blade groups. Each cutting blade group includes several cutting blade plates 5012 that are hinged sequentially. The cutting blade plates 5012 are hinged to the triangular ring plate 5011. A cutting blade 5013 is provided at one end of the cutting blade plate 5012, and a cleaning roller 5014 is provided at the other end. Furthermore, an electric motor extends outward from the rotation axis of several cutting blade plates 5012.

[0073] Operation process: PP flame-retardant raw materials of the corresponding formulations are fed into the surface extruder 101, intermediate extruder 201, and inner extruder 2041 respectively. The temperature parameters of each extruder are set according to the characteristics of the raw materials, and the extruders are started. After the extruders run stably and the screw speed reaches the set value, the raw materials of each layer melt to form a melt. The surface melt is conveyed through the first connecting pipe 103, the intermediate melt through the second connecting pipe 203, and the inner melt through the intermediate extrusion port 2042, and respectively to the corresponding cavities of the combined extruder head 205.

[0074] The surface melt enters the first pipe cavity 2051, the intermediate melt enters the second pipe cavity 2052, and the inner melt directly enters the co-extrusion cavity 2053. Within the co-extrusion cavity 2053, the melt is guided by flow channels to achieve layered encapsulation and fusion, forming a three-layer melt structure of "inner layer-intermediate layer-surface layer". The fused melt enters the combined extruder head 205 and is then extruded through the retention groove 302 of the connecting plate 301. At this time, the micro motor 3042 of the clamping component is activated, and the cam 3043 rotates to push the pressing plate 3041 downwards, pressing the edge of the extruded sheet tightly within the retention groove 302 to prevent warping. The resetting action of the elastic element 3044 ensures stable pressing force and guarantees the sheet forming accuracy.

[0075] After molding, the three-layer co-extruded sheet enters the extrusion channel between two guide rollers 1003. The guide rollers 1003 rotate synchronously, smoothly conveying the sheet to the receiving frame 1004.

[0076] The flame-retardant material is then formed into a planar strip and received by the second receiving plate 402. The rotation of the rotating wheel 4061 causes the conveyor belt 4062 to move, which in turn drives the sliding of the two sliders 4063. Because the two sliders 4063 move in opposite directions, the second receiving plate 402 and the first receiving plate 401 move in opposite directions. Since the wheel 4051 at the lower end of the second receiving plate 402 moves along the direction of the first transverse groove 403 and the second transverse groove 404, when the second receiving plate 402 moves to the lower end of the first receiving plate 401, the flame-retardant sheet is cut by the cutting component 500.

[0077] Example 2

[0078] Reference Figure 1-2This embodiment discloses a temperature control method for a flame-retardant sheet production line made from waste plastics, including the following steps:

[0079] (a) Stage 1: Setting the temperature gradient for raw material melting and extrusion

[0080] Temperature setting for surface extruder 101: Based on the melting characteristics of the surface PP flame-retardant raw material, the temperature gradient of the barrel is set in three temperature control zones: feeding zone 160-170℃, melting zone 180-190℃, and homogenization zone 190-200℃. The temperature controller adopts PID regulation. When the sensor detects that the temperature of a certain area is lower than the target value, it automatically increases the power of the corresponding heating coil. When it is higher than the target value, it reduces the power or stops heating, controlling the temperature fluctuation range to ≤±2℃.

[0081] Temperature setting for intermediate layer extruder 201: The melt viscosity of the intermediate layer raw material is slightly higher. Set the corresponding temperature gradient: 155-165℃ for the feeding zone, 175-185℃ for the melting zone, and 185-195℃ for the homogenization zone. The temperature fluctuation is controlled to be ≤±2℃. The temperature difference between the intermediate layer and the surface layer is kept stable at 5-10℃ by an independent temperature controller.

[0082] Temperature settings for inner layer extruder 2041: Inner layer raw materials are easily degraded, so a lower temperature gradient is set: feeding zone 150-160℃, melting zone 170-180℃, homogenization zone 180-190℃, temperature fluctuation controlled ≤±2℃, and the temperature difference with the middle layer is maintained at 5℃, forming an overall temperature gradient of "surface layer > middle layer > inner layer".

[0083] (II) Stage 2: Temperature control of melt conveying channel

[0084] First / Second connecting pipe 203 insulation: The melt temperature threshold inside the connecting pipe is set to 95% of the homogenization zone temperature of the corresponding extruder. When the sensor detects that the temperature of the connecting pipe is lower than the threshold, the temperature controller of the corresponding extruder automatically starts the heating belt. The power of the heating belt is dynamically adjusted according to the temperature difference to ensure that the temperature of the melt is still maintained above 95% of the homogenization zone temperature when it reaches the die head, so as to avoid the melt viscosity from increasing due to temperature drop.

[0085] (III) Stage 3: Temperature Matching Control of 205 Zones in the Combined Extruder Head

[0086] Temperature control of the first pipeline cavity 2051: The target temperature is set to the homogenization zone temperature of the surface extruder 101. The temperature is adjusted by the temperature controller through the heating element, and the fluctuation is controlled to be ≤±1℃ to ensure that the surface melt temperature is stable in the channel and that no secondary cooling occurs.

[0087] Temperature control of the second pipe cavity 2052: Set the target temperature to the homogenization zone temperature of the intermediate layer extruder 201, and maintain a temperature difference of 5-10℃ with the first pipe cavity 2051 to match the melt viscosity difference and avoid excessive interlayer shear force leading to delamination.

[0088] Temperature control of co-extrusion chamber 2053: The target temperature is set as (temperature of surface homogenization zone + temperature of intermediate homogenization zone + temperature of inner homogenization zone) / 3, which serves as a transition temperature zone to ensure a gentle temperature gradient during the fusion of the three melt layers, reducing interlayer bonding defects caused by sudden temperature changes. When the sensor detects that the temperature of co-extrusion chamber 2053 deviates from the target value, the temperature controller first adjusts the temperature of the intermediate heating zone, and then fine-tunes the surface and inner heating zones to ensure overall temperature stability.

[0089] (iv) Stage 4: Fine-tuning control of extrusion molding end temperature

[0090] The target temperature inside the storage tank 302 is set to be lower than the temperature of the co-extrusion cavity 2053. When the sensor detects that the temperature of the storage tank 302 is too low, the micro heating element is activated by the temperature controller. The power of a single heating element is output according to the temperature difference. Local heating is used to prevent the edge of the sheet from warping or cracking due to excessive cooling. If the temperature is too high, the micro heating element is stopped, and the heat dissipation of the clamping parts is used to assist in cooling, ensuring that the temperature is within the optimal range when the sheet is formed.

[0091] Differentiated temperature gradients are set to address the varying melting requirements of the surface, middle, and inner layers of flame-retardant PP raw materials, preventing raw material degradation or incomplete melting and ensuring the quality of each layer's melt. Insulation of connecting pipes and zoned temperature control at the die head reduce temperature loss during melt transport, allowing for a smooth temperature transition within the co-extrusion chamber 2053 and enhancing interlayer bonding strength. Fine-tuning of the temperature at the extrusion molding end resolves sheet edge warping issues, while closed-loop control ensures minimal temperature fluctuations.

[0092] It is important to note that the constructions and arrangements of this application shown in several different exemplary embodiments are merely illustrative. Although only a few embodiments are described in detail in this disclosure, those who consult this disclosure will readily understand that many modifications are possible (e.g., changes in the size, dimensions, structure, shape, and proportions of various elements, as well as parameter values ​​(e.g., temperature, pressure, etc.), installation arrangements, use of materials, color, orientation, etc.) without substantially departing from the novel teachings and advantages of the subject matter described in this application. For example, an element shown as integrally formed may be composed of multiple parts or elements, the position of elements may be inverted or otherwise altered, and the nature or number or position of discrete elements may be changed or altered. Therefore, all such modifications are intended to be included within the scope of the invention. The order or sequence of any process or method steps may be changed or rearranged according to alternative embodiments. In the claims, any "device plus function" clause is intended to cover the structure described herein that performs the function, and not only structurally equivalent but also equivalent in structure. Other substitutions, modifications, alterations, and omissions may be made in the design, operation, and arrangement of the exemplary embodiments without departing from the scope of the invention. Therefore, the present invention is not limited to the specific embodiments, but extends to various modifications that still fall within the scope of the appended claims.

[0093] Furthermore, in order to provide a concise description of exemplary embodiments, not all features of actual embodiments (i.e., those features that are not relevant to the currently considered best mode for carrying out the invention, or those features that are not relevant to implementing the invention) may be omitted.

[0094] It should be understood that numerous specific implementation decisions can be made during the development of any practical implementation, such as in any engineering or design project. Such development efforts may be complex and time-consuming, but for those skilled in the art who benefit from this disclosure, the development effort will be a routine work of design, manufacturing, and production without requiring much experimentation.

[0095] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A production line for flame-retardant sheets made from waste plastics, characterized in that: include: Main frame (1001). The surface extrusion assembly (100) includes a surface extruder (101), an extrusion port (102) disposed on the surface extruder (101), and a first connecting pipe (103) disposed on the extrusion port (102). The intermediate layer extrusion assembly (200) includes an intermediate layer extruder (201), a layer extrusion port (202) disposed on the intermediate layer extruder (201), and a second connecting pipe (203) disposed on the layer extrusion port (202). The inner extrusion assembly (204) includes an inner extruder (2041) and an intermediate extrusion port (2042) disposed on the inner extruder (2041). The combined extruder head (205) is connected to the intermediate extrusion port (2042), the first connecting pipe (103) and the second connecting pipe (203). The combined extruder head (205) is provided with an extrusion component (300). Temperature control components (206) include a surface extruder temperature control structure (2061), an intermediate extruder temperature control structure (2062), and an inner extruder temperature control structure (2063). A conveying and cutting assembly (400) is disposed near the extrusion part (300).

2. The flame-retardant sheet production line made from waste plastics as described in claim 1, characterized in that: The combined extruder head (205) has a first pipe cavity (2051) inside, which is connected to the first connecting pipe (103). The combined extruder head (205) has a second pipe cavity (2052) inside, which is located outside the second pipe cavity (2052). The second pipe cavity (2052) is connected to the second connecting pipe (203). The intermediate extrusion port (2042) forms a co-extrusion cavity (2053). The first pipe cavity (2051) and the second pipe cavity (2052) are both connected to the co-extrusion cavity (2053).

3. The flame-retardant sheet production line made from waste plastics as described in claim 1, characterized in that: The extrusion component (300) includes a connecting plate (301) connected to the combined extruder head (205) and a storage groove (302) formed on the connecting plate (301). A retaining edge (303) is provided in the storage groove (302). A clamping member is provided in the retaining edge (303). The clamping member includes a pressing plate (3041) provided in the retaining edge (303). A micro motor (3042) is provided in the retaining edge (303). A cam (3043) is provided on the micro motor (3042). The edge of the cam (3043) abuts against the upper edge of the pressing plate (3041). An elastic member (3044) is provided between the pressing plate (3041) and the retaining edge (303).

4. The flame-retardant sheet production line made from waste plastics as described in claim 1, characterized in that: The main frame (1001) is provided with a roller frame (1002), and the roller frame (1002) is provided with a guide roller (1003). There are two guide rollers (1003), and an extrusion channel is formed between the two guide rollers (1003). The main frame (1001) is provided with a receiving frame (1004) near the roller frame (1002), and the conveying and cutting assembly (400) is provided on the receiving frame (1004).

5. The flame-retardant sheet production line made from waste plastics as described in claim 4, characterized in that: The conveying and cutting assembly (400) includes a first receiving plate (401) and a second receiving plate (402) slidably connected to the receiving frame (1004), a first transverse groove (403) and a second transverse groove (404) formed on the inner wall of the receiving frame (1004), an inclined groove provided between the first transverse groove (403) and the second transverse groove (404), a pull rod (405) provided on the second receiving plate (402), a wheel (4051) provided at the lower end of the pull rod (405), the wheel (4051) cooperating with the first transverse groove (403), the second transverse groove (404) and the inclined groove, a conveying component (406) provided inside the receiving frame (1004), and a cutting component (500) provided on the bottom surface of the first receiving plate (401).

6. The flame-retardant sheet production line made from waste plastics as described in claim 5, characterized in that: The cutting component (500) includes several stops at the lower end of the first receiving plate (401), a suction cup plate (502) at the lower end of the first receiving plate (401), and several spray tubes (503) on the suction cup plate (502). The stops include several triangular ring plates (5011) of increasing size, which are nested together. Each triangular ring plate (5011) is pushed by a cylinder (5001). The suction cup plate (502) is disposed between the triangular ring plates (5011).

7. The flame-retardant sheet production line made from waste plastics as described in claim 6, characterized in that: The lower end of the first receiving plate (401) is detachably bolted to a movable guide rail (504), a push block (505) is slidably connected on the movable guide rail (504), a lead screw (506) is provided on the push block (505), a drive motor for driving the lead screw (506) to rotate is provided at the end of the movable guide rail (504), and a cylinder (5001) is provided on the push block (505); The lower end of the first receiving plate (401) is provided with a baffle (507) for installing a stop. The baffle (507) is detachably connected to the triangular ring plate (5011). An entry hole is provided on the baffle (507) corresponding to the triangular ring plate (5011).

8. The flame-retardant sheet production line made from waste plastics as described in claim 7, characterized in that: The triangular ring plate (5011) consists of three sets of cutting blade groups that are hinged to each other. Each cutting blade group includes several cutting blade plates (5012) that are hinged to each other in sequence. The cutting blade plates (5012) are hinged to the triangular ring plate (5011). One end of the cutting blade plate (5012) is provided with a cutting blade (5013), and the other end is provided with a cleaning roller (5014).

9. A temperature control method for a flame-retardant sheet production line made from waste plastics as described in any one of claims 1-8, characterized in that: include, Based on the melting characteristics of PP flame-retardant raw materials, the gradient temperature for raw material melting and extrusion is set; The melt temperature threshold in the first connecting pipe (103), the second connecting pipe (203), and the intermediate extrusion port (2042) is set to 95% of the temperature of the homogenization zone of the corresponding extruder. When the sensor detects that the temperature of any one of the components in the first connecting pipe (103), the second connecting pipe (203), and the intermediate extrusion port (2042) is lower than the threshold, the temperature controller of the corresponding extruder automatically starts the heating belt, and the power of the heating belt is dynamically adjusted according to the temperature difference. Perform zoned temperature matching control within the combined extruder head (205); Perform fine-tuning control of the extrusion molding end temperature.

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