Co-extrusion plastic template and preparation method thereof

Abstract

The invention discloses a co-extrusion plastic formwork and a preparation method thereof.The plastic formwork comprises an inner co-extrusion layer and an outer surface co-extrusion layer integrally formed with the inner co-extrusion layer, the plastic formwork is machined and formed with the outer surface through a PA co-extrusion technology with PVC as base metal, the two sides of the plastic formwork are provided with side reinforcing ribs of a hollow structure, and the side reinforcing ribs are arranged on the outer surface of the plastic formwork. A plurality of middle reinforcing ribs which are arranged at intervals are arranged between the side reinforcing ribs, the middle reinforcing ribs are arranged in a hollow structure, and a sealing structure is formed by the plastic formworks through sealing covers along the ends of the middle reinforcing ribs; the plurality of connected plastic templates are fixed through connecting pieces along the longitudinal direction, the internal co-extrusion layer is a co-extrusion layer made of a PVC (Polyvinyl Chloride) material, the external surface co-extrusion layer is a co-extrusion layer made of a PA (Polyamide) material, the internal co-extrusion layer forms a plurality of independent spaced cavity structures, and the spaced cavity structures are arranged in a through manner.

Description

Technical Field

[0001] The invention belongs to the technical field of construction, and particularly relates to a co-extruded plastic template and a preparation method thereof. Background Art

[0002] Plastic formwork has been applied to the construction industry, including injection molded formwork and extrusion formwork. Injection molded formwork requires a large investment and is not suitable for processing small-scale formwork of different specifications. PA material has a high moisture absorption rate, and humidity has a significant impact on its dimensional stability. In addition, the material cost of PA is relatively high, so PA injection molded formwork is rarely used alone. Extruded plastic formwork molds have advantages over injection molded plastic formwork, such as lower investment. Extrusion formwork uses a single material such as PVC, ABS, etc. Single-material plastic formwork is easy to extrude, but the formwork is easily damaged after multiple turnovers during use, making it unusable. In addition, there is a problem of bonding with the formwork after pouring concrete during use. At the same time, plastic formwork needs to be mixed with aluminum formwork during use. Injection molded formwork is mostly a hollow flat plate structure that is not suitable for connection.

[0003] In view of the above factors, a co-extruded plastic formwork and a preparation method thereof are provided. PA film is used for compounding on the contact surface between the extruded formwork and the concrete and on the two side surfaces adjacent to the contact surface, which can improve the wear resistance and strength of the formwork surface. At the same time, due to the non-stickiness of PA, it can have a good anti-stick effect after pouring concrete, making the plastic formwork easy to demold. Summary of the Invention

[0004] The object of the present invention is to provide a co-extruded plastic template and a preparation method thereof to solve the problems raised in the above background technology.

[0005] The object of the present invention is achieved through the following technical solutions: a co-extruded plastic template, the plastic template includes an inner co-extruded layer and an outer surface co-extruded layer integrally formed with the inner co-extruded layer, the plastic template is made of PVC as a base material and the outer surface is processed and formed by a PA co-extrusion process;

[0006] The plastic template has hollow side reinforcement ribs on both sides, and a plurality of spaced intermediate reinforcement ribs are provided between the side reinforcement ribs. The intermediate reinforcement ribs are hollow, and sealing caps are provided along the ends of the intermediate reinforcement ribs to form a sealed structure for the plastic template.

[0007] A plurality of the plastic templates are provided, and the plurality of connected plastic templates are fixed along the longitudinal direction by connecting pieces.

[0008] Furthermore, the inner co-extruded layer is a co-extruded layer of PVC material, the outer surface co-extruded layer is a co-extruded layer of PA material, the inner co-extruded layer forms a plurality of independent spaced cavity structures, and the spaced cavity structures are arranged in a through form;

[0009] The spacer cavity structure includes internal longitudinal reinforcing ribs and internal cross beam ribs, the internal longitudinal reinforcing ribs and the internal cross beam ribs are co-extruded, and the internal cross beam ribs are partition layers, and the partition layers are horizontal or have a broken line structure.

[0010] The spacing between the internal longitudinal reinforcement ribs is controlled between 15mm-20mm, and the distance between the internal crossbeam ribs and the inner wall of the slab top on the concrete pouring side is between 7mm-9mm.

[0011] Furthermore, the hollow support columns are formed by co-extrusion in the spaced cavity structures between the adjacent intermediate reinforcement ribs;

[0012] A hollow support column is provided in the middle reinforcing rib at the same position as the spacer cavity structure;

[0013] The plastic templates between adjacent intermediate reinforcement ribs form an arc structure, the side reinforcement ribs and the intermediate reinforcement ribs are protrudingly arranged, and a supporting sealing plate is provided inside the intermediate reinforcement ribs.

[0014] Furthermore, the connecting member includes a first connecting member and a second connecting member, and a plurality of connected plastic templates are fixed along the longitudinal direction by the first connecting member and / or the second connecting member.

[0015] Furthermore, the side reinforcement ribs on both sides of the plastic template are provided with mounting protrusions that cooperate with the first connecting member;

[0016] The inner side of the sealing cover of the plastic template is provided with a mounting protrusion that cooperates with the first connecting member;

[0017] The connection points of the sealing covers connected to the plastic templates are fixed by a first connecting member and / or a second connecting member.

[0018] Furthermore, the sealing cover is provided with mounting protrusions and extension plates that cooperate with the middle reinforcement ribs, the mounting protrusions are arranged at intervals on the sealing cover, and the distances between the mounting protrusions and adjacent middle reinforcement ribs are the same;

[0019] The extension plates are located below the mounting protrusions, are spaced apart, are arranged in an arc-shaped structure, and are arranged horizontally. The extension plates cooperate with the plastic templates between the adjacent middle reinforcement ribs to form an arc-shaped structure.

[0020] The extension plate cooperates with a plurality of independent spaced cavity structures formed by the internal co-extruded layer, and the extension plate penetrates into the inner side of the extruded spaced cavity structure and cooperates with the inner wall of the plastic template;

[0021] The extension plate is bonded to the inner wall by using adhesive to form a plurality of independent spaced cavity structures formed by the internal co-extruded layer, and the sealing cover is fastened to the connection hole on the middle reinforcement rib by screws on the outside to form a whole;

[0022] Or the sealing cover is provided with spaced through holes.

[0023] Furthermore, the first connecting member includes a body, a forming cavity is provided on the body, and symmetrical flange structures are provided along both sides of the bottom of the forming cavity;

[0024] The inner side of the molding cavity is provided with a forming groove that matches the plastic template, and the forming groove matches the arc protrusion on the plastic template;

[0025] The main body is also provided with a press-type structure, and the press-type structure contacts and cooperates with the adjacent end surface of the plastic template;

[0026] The forming groove is an arc-shaped groove structure, the forming groove is arranged at intervals above and below or is provided alone, and the forming groove is a through groove structure symmetrically arranged along the inner wall of the forming cavity;

[0027] A plane structure is formed on the press structure, and a disassembly gap is formed between the plane structure formed on the press structure and the forming cavity.

[0028] Furthermore, the second connecting member includes a pin and a gasket fitted on the pin, two gaskets are provided, and the gaskets are installed on both sides of the side reinforcement ribs of adjacent plastic templates;

[0029] A pin hole is provided at the end of the pin shaft, a pin is provided in the pin hole, and the pin is provided in a wedge-shaped structure.

[0030] The preparation method of the co-extruded plastic template comprises the following steps:

[0031] The raw materials are mixed with additives to prepare PVC as the base material and PA material particles; the raw materials are respectively put into the hot mixer for mixing, and after dehumidification to remove moisture, they are discharged into the cold mixer, after removing foreign matter, they are put into the storage tank and homogenized to obtain the mixture;

[0032] Adjust the extruder parameters according to the product characteristics and process requirements;

[0033] The inner layer PVC plastic particles and the middle layer hot melt adhesive particles and PA particles are added to different extruders respectively. The PVC plastic particles enter the main extruder, and the PA particles and the middle layer hot melt adhesive particles enter the co-extruder. After heating and melting, the co-extrusion distributor in the mold evenly distributes the materials of each layer and extrudes them together.

[0034] Among them, PVC particles enter the main extruder and enter the multi-piece side-by-side die to be extruded into PVC profiles. Hot-melt adhesive particles enter the injection hole of the die extrusion piece M5 through the co-extruder on one side, are distributed to the four end points through the internal flow channel, enter the four-way hole of the die extrusion piece M4, and flow into the flow channel of the die extrusion piece M4 so that the liquid fluid formed by the hot-melt adhesive particles is evenly distributed to the surface of the PVC profile. PA particles enter the injection hole of the die extrusion piece M3 through the co-extruder on the other side, are distributed to the four end points through the internal flow channel, enter the four-way hole of the die extrusion piece M2, and flow into the flow channel of the die extrusion piece M2 so that the liquid fluid formed by the PA particles is evenly distributed to the surface of the PVC profile to co-extrude the hot-melt adhesive. During the co-extrusion process, each die piece is grooved on one side to form a flow channel, and the back is a flat structure. The flow channel cavity is formed by the flat structure of the front extrusion piece to achieve co-extrusion;

[0035] After the above three-layer co-extrusion, the extruded template enters the cooling and shaping device for cooling to avoid surface deformation. The extruded plastic template blank is cooled by a vacuum cooling and shaping table to cool it down and solidify it to maintain a stable shape.

[0036] The cooled template is transferred to the cutting equipment through the traction device and cut into the required length;

[0037] Among them: the processing temperature of PVC is between 160-190℃; the processing temperature of hot melt adhesive is usually between 160-200℃; the processing temperature of PA is between 240-280℃.

[0038] The invention discloses an application of a preparation method of a co-extruded plastic formwork, and applies the preparation method of the co-extruded plastic formwork to the construction industry. Through the co-extrusion process, multiple performance requirements are achieved in a one-time molding process, and a good anti-sticking effect can be achieved after pouring concrete, making the plastic formwork easy to demould.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The present invention utilizes a PA film laminate on the contact surface between the extrusion formwork and concrete, as well as on the adjacent side surfaces, to enhance the formwork's surface wear resistance and strength. Furthermore, the PA's non-stick properties provide excellent anti-stick properties after concrete pouring, facilitating demolding of the plastic formwork. Reinforcement ribs are designed on both sides of the formwork, at the same height as the aluminum alloy formwork. These ribs are equipped with specialized clip protrusions and pin connection holes, allowing for inter-use with aluminum alloy formwork, installation between plastic formworks, or installation between plastic formworks using a dedicated clip connection.

[0041] Through co-extrusion, this invention achieves multiple performance requirements, such as strength, wear resistance, and weather resistance, in a single molding process. This makes the overall performance of the plastic formwork superior to that of traditional single-layer formwork. It also rationally utilizes recycled materials of varying prices, reducing raw material costs. Furthermore, it eliminates some intermediate steps, such as granulation, reducing energy consumption and labor costs.

[0042] The co-extrusion process of the present invention reduces waste generation in the production process, and the plastic template can be recycled, meeting environmental protection requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a three-dimensional schematic diagram of the present invention;

[0044] Figure 2 It is a side schematic view of the present invention;

[0045] Figure 3 This is a schematic diagram of the plastic template splicing plan of the present invention;

[0046] Figure 4 This invention Figure 3 A partial enlarged schematic diagram;

[0047] Figure 5 This is a three-dimensional schematic diagram of the plastic template splicing of the present invention;

[0048] Figure 6 This invention Figure 5 Schematic diagram of the rear end face;

[0049] Figure 7 This invention Figure 6 A in the middle is an enlarged schematic diagram;

[0050] Figure 8 This invention Figure 6 The enlarged schematic diagram of point B in the middle;

[0051] Figure 9 is a three-dimensional schematic diagram of the first connecting member of the present invention;

[0052] Figure 10 is a three-dimensional schematic diagram of the second connecting member of the present invention;

[0053] Figure 11 This is a schematic diagram of another three-dimensional state of the second connecting member of the present invention;

[0054] Figure 12 This is a schematic diagram of the connection between the plastic template and the sealing cover of the present invention;

[0055] Figure 13 It is a three-dimensional schematic diagram of the sealing cover of the present invention;

[0056] Figure 14 This is a three-dimensional schematic diagram of the sealing cover of the present invention in another state;

[0057] Figure 15 It is a three-dimensional schematic diagram of the extrusion die of the present invention;

[0058] Figure 16 Schematic diagram of die extruded sheet M1 of the present invention;

[0059] Figure 17 Schematic diagram of die extruded sheet M2 of the present invention;

[0060] Figure 18 Schematic diagram of die extruded sheet M3 of the present invention;

[0061] Figure 19 Schematic diagram of die extruded sheet M4 of the present invention;

[0062] Figure 20 It is a schematic diagram of the die extruded sheet M5 of the present invention. DETAILED DESCRIPTION

[0063] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0064] In the description of the present invention, it should be noted that, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0065] In the description of the present invention, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0066] like Figure 1-20 As shown, a co-extruded plastic template comprises an inner co-extruded layer 1 and an outer surface co-extruded layer 2 integrally formed with the inner co-extruded layer 1. The plastic template is formed by using PVC as the base material and the outer surface is processed and formed by using PA co-extrusion process;

[0067] The plastic template has hollow side reinforcement ribs 3 on both sides, and a number of spaced intermediate reinforcement ribs 4 are provided between the side reinforcement ribs 3. The intermediate reinforcement ribs 4 are hollow, and sealing caps 5 are provided along the ends of the intermediate reinforcement ribs 4 to form a sealed structure for the plastic template.

[0068] The sealing cover is as follows Figure 13 In addition to the styles shown, it also includes Figure 14 The sealing cover structure of the style shown.

[0069] The sealing cover is as follows Figure 13 In addition to the styles shown, it also includes Figure 14 The sealing cover structure shown in the style adopts Figure 14 The sealing cover structure shown has a through hole provided on the sealing cover, and the through hole allows for pin connection and clip connection.

[0070] A plurality of the plastic templates are provided, and the plurality of connected plastic templates are fixed along the longitudinal direction by connecting pieces.

[0071] In order to facilitate the use of the plastic formwork, the inner co-extrusion layer 1 is a co-extrusion layer of PVC material, and the outer surface co-extrusion layer 2 is a co-extrusion layer of PA material. The inner co-extrusion layer 1 forms a plurality of independent spaced cavity structures 6, and the spaced cavity structures 6 are arranged in a through-type manner.

[0072] In order to facilitate use, according to different use states, the spacer cavity structure 6 includes internal longitudinal reinforcing ribs and internal cross beam ribs, the internal longitudinal reinforcing ribs and the internal cross beam ribs are co-extruded, and the internal cross beam ribs are the partition layer 7, and the partition layer 7 adopts a horizontal structure or a broken line structure.

[0073] The spacing between the internal longitudinal reinforcement ribs is controlled between 15mm-20mm, and the distance between the internal crossbeam ribs and the inner wall of the slab top on the concrete pouring side is between 7mm-9mm.

[0074] In order to facilitate the use of the hollow support column 8 in the middle reinforcement rib 4 to form a structural support, the hollow support column 8 is co-extruded in the interval cavity structure 6 between adjacent middle reinforcement ribs 4;

[0075] A hollow support column 8 is provided in the middle reinforcing rib 4 at the same position as the spacer cavity structure;

[0076] The plastic template between adjacent intermediate reinforcement ribs 4 forms an arc structure 9 , the side reinforcement ribs 3 and the intermediate reinforcement rib 4 are protrudingly arranged, and a supporting sealing plate 10 is provided inside the intermediate reinforcement rib 4 .

[0077] In order to facilitate the connection and fixation of adjacent spliced ​​plastic templates in use, the connecting parts include a first connecting part 11 and a second connecting part 12. Several connected plastic templates are fixed along the longitudinal or transverse direction through the first connecting part 11 and / or the second connecting part 12.

[0078] In order to facilitate fixing the plastic template by the first connecting member 11 in the use state, the side reinforcing ribs 3 on both sides of the plastic template are provided with mounting protrusions 13 that cooperate with the first connecting member 11;

[0079] The inner side of the sealing cover 5 of the plastic template is provided with a mounting protrusion 13 that cooperates with the first connecting member 11;

[0080] The connection points of the sealing covers 5 connected to the plastic template are fixed by a first connecting member 11 and / or a second connecting member 12 .

[0081] The first connecting member 11 and the second connecting member 12 can be fixed at different positions in the spliced ​​state.

[0082] When the plastic templates are spliced ​​together, the connection between the sealing cover 5 of the plastic template is fixed by the first connecting member 11 and / or the second connecting member 12;

[0083] When the plastic templates are spliced ​​together, they are fixed in the longitudinal direction of the plastic templates by the first connecting member 11 and / or the second connecting member 12;

[0084] In order to improve the overall performance of the sealing plate and the template body by the dual connection method of bonding and bolting the extension plate to the inner wall in the use state, the sealing cover 5 is provided with mounting protrusions 13 and extension plates 14 that cooperate with the intermediate reinforcement ribs 4. The mounting protrusions 13 are arranged at intervals on the sealing cover 5, and the distance between the mounting protrusions 13 and adjacent intermediate reinforcement ribs 4 is the same;

[0085] The extension plates 14 are located below the mounting protrusions 13 . The extension plates 14 are spaced apart and arranged in an arc-shaped structure and are arranged horizontally. The extension plates 14 cooperate with the plastic templates between the adjacent middle reinforcing ribs 4 to form an arc-shaped structure 9 .

[0086] The extension plates 14 are arranged at intervals and are arranged in an arc-shaped structure and a horizontal structure, and are arranged on the inner end surface of the sealing cover 5, with the arc-shaped structure being arranged above the horizontal structure.

[0087] The extension plate 14 cooperates with the multiple independent spaced cavity structures formed by the internal co-extruded layer 1, and the extension plate 14 penetrates into the inner side of the extruded spaced cavity structure and cooperates with the inner wall of the plastic template;

[0088] The extension plate is bonded to the inner wall with several independent spaced cavity structures 6 formed by the internal co-extruded layer 1 by adhesive, and the sealing cover 5 is fastened to the connection holes on the middle reinforcing rib 4 by screws on the outside to form a whole.

[0089] Bolt connection holes are arranged at intervals on the sealing cover 5. Two groups of bolt connection holes are arranged in the upper and lower parts, and the bolt connection holes correspond to the hollow support columns 8 on the plastic template. Both ends of the hollow support columns 8 are bolt connection ports, and the sealing cover and the plastic template are fastened with bolts.

[0090] The above-mentioned sealing cover is designed with a bolt connection hole and an extension plate on the side. The extension plate can penetrate into the inner side of the extrusion template cavity and cooperate with the inner wall of the plastic template. During installation, the extension plate can be bonded to the inner wall of the extrusion template with an adhesive, and the sealing cover and the reinforcement connection hole on the end face of the plastic template, that is, the hollow support column, are fastened to form a whole by screws on the outside. The sealing cover can also be connected to the plastic template body in one of two ways according to usage needs.

[0091] The double connection method of bonding and bolting the extension plate to the inner wall can improve the overall performance of the sealing plate and the plastic formwork body.

[0092] When assembling the above-mentioned plastic templates, when the plastic templates need to be lengthened in the length direction, the first connecting member and the pins can be used to connect in the length direction, thereby lengthening the plastic templates while meeting the strength requirements of the board surface.

[0093] In order to facilitate the fixation of the plastic template in use, the first connecting member 11 includes a body 11A, a molding cavity 11B is provided on the body 11A, and symmetrical flange structures 11C are provided along both sides of the bottom of the molding cavity 11B;

[0094] The inner side of the molding cavity 11B is provided with a forming groove 11D that cooperates with the plastic template, and the forming groove 11D cooperates with the arc protrusion on the plastic template;

[0095] The body 11A is further provided with a press-type structure 11E, which contacts and cooperates with the adjacent end surface of the plastic template;

[0096] The forming groove 11D is an arc-shaped groove structure, and the forming groove 11D is arranged at intervals up and down or is provided alone, and the forming groove 11D is a through groove structure symmetrically arranged along the inner wall of the forming cavity 11B;

[0097] A plane structure is formed on the press-forming structure 11E, and a disassembly gap is formed between the plane structure formed on the press-forming structure 11E and the molding cavity 11B.

[0098] The first connecting member is used above. When in use, the groove 11D formed on the upper end of the first connecting member cooperates with the mounting protrusion on the plastic template to fix the adjacent plastic templates.

[0099] The molding cavity of the main body has an arc groove that cooperates with the arc protrusion of the plastic template to achieve the effect of clamping and fixing. Two flange structures are set on both sides of the lower end of the main body, which can be used in conjunction with special calipers. The calipers can control the opening of the clamp to facilitate the installation of the clamp and the template. M-shaped pressed structures are symmetrically set on both sides of the upper part of the main body. This structure can be used to position the arc groove of the clamp and the arc protrusion of the template to avoid installation misalignment. It can also serve as another way of disassembly. When the clamp is not used for disassembly, a crowbar can be used to directly penetrate the disassembly gap formed by the M-shaped structure and the upper surface of the molding cavity. The end of the crowbar is pressed on the metal upper surface of the M structure, and the main body can be pried to achieve disassembly.

[0100] In order to increase the firmness of the connection between the plastic templates in use, the second connecting member 12 includes a pin 12A and a gasket 12B fitted on the pin 12A. Two gaskets 12B are provided, and the gaskets 12B are installed on both sides of the side reinforcing ribs 3 of adjacent plastic templates.

[0101] A pin hole is provided at the end of the pin shaft 12A, and a pin 12C is provided in the pin hole. The pin 12C is a wedge-shaped structure.

[0102] During the use of the plastic formwork, it is necessary to drill holes in the middle of the plastic formwork to install tension bolts according to the design of the formwork. The setting of the tension bolt holes will vary according to different project locations. The turnover cycle of the plastic formwork is required to be more than 25 times. If the drilled areas need to be sealed during use, a special plugging structure is designed to seal the formwork facing the concrete side to avoid problems such as prefabricated voids and leakage during concrete pouring. The plugging cover adopts an elastic structure at the end, with the middle having the same diameter as the prefabricated hole and the tail adopting a plugging cover structure larger than the hole diameter. It can be installed on the surface of the prefabricated hole without falling off. It can be removed when it needs to be used again. The plugging cover is made of the same PA material as the covering.

[0103] The tensioning and tightening gasket method uses tensioning gaskets to be installed on both sides of the reinforcement. One side of the middle installation hole of the gasket is a protruding round tube structure, and the other side is a round hole gasket structure. After the tensioning plates on both sides are installed, the protruding round tube structure that is higher than the round hole gasket is pressed and anchored on the gasket through mechanical equipment to fix the whole on both sides of the reinforcement.

[0104] like Figure 10As shown, the above-mentioned gasket is arranged into a long washer pin structure, and the long round hole washer is used in conjunction with the pin. The gasket is installed on both sides of the template reinforcement rib to increase the surface hardness while increasing the contact area between the pin and the template, making the template more firm and reliable after fixation.

[0105] like Figure 11 As shown, due to the low hardness of the plastic formwork itself, when pins are used to connect the formworks or the plastic formworks and the aluminum formwork, the wedge-shaped fastening pieces of the pins will be pressed into the mother material of the reinforcing ribs on both sides of the formwork, causing damage to the formwork. This structure adopts a hot-melt gasket structure. The hot-melt gasket adopts a long structure, and the length direction is the same as the extrusion direction of the plastic mold. The hot-melt gasket is designed with hot-melt pins around it and a pin hole in the middle. When installing, drill holes at the corresponding parts of the hot-melt pins around the gasket. After heating, the hot-melt pins can be directly installed on both sides of the reinforcing ribs.

[0106] The preparation method of the co-extruded plastic template comprises the following steps:

[0107] The raw materials are mixed with additives to prepare PVC as the base material and PA material particles; the raw materials are respectively put into the hot mixer for mixing, and after dehumidification to remove moisture, they are discharged into the cold mixer, after removing foreign matter, they are put into the storage tank and homogenized to obtain the mixture;

[0108] Adjust the extruder parameters according to the product characteristics and process requirements;

[0109] The inner layer PVC plastic particles and the middle layer hot melt adhesive particles and PA particles are added to different extruders respectively. The PVC plastic particles enter the main extruder, and the PA particles and the middle layer hot melt adhesive particles enter the co-extruder. After heating and melting, the co-extrusion distributor in the mold evenly distributes the materials of each layer and extrudes them together.

[0110] Among them, PVC particles enter the main extruder and enter the multi-piece side-by-side die to be extruded into PVC profiles. Hot-melt adhesive particles enter the injection hole of the die extrusion piece M5 through the co-extruder on one side, are distributed to the four end points through the internal flow channel, enter the four-way hole of the die extrusion piece M4, and flow into the flow channel of the die extrusion piece M4 so that the liquid fluid formed by the hot-melt adhesive particles is evenly distributed to the surface of the PVC profile. PA particles enter the injection hole of the die extrusion piece M3 through the co-extruder on the other side, are distributed to the four end points through the internal flow channel, enter the four-way hole of the die extrusion piece M2, and flow into the flow channel of the die extrusion piece M2 so that the liquid fluid formed by the PA particles is evenly distributed to the surface of the PVC profile to co-extrude the hot-melt adhesive. During the co-extrusion process, each die piece is grooved on one side to form a flow channel, and the back is a flat structure. The flow channel cavity is formed by the flat structure of the front extrusion piece to achieve co-extrusion;

[0111] The difference between the die extrusion piece M4 and the die extrusion piece M2 is that the gaps in the middle cavities are different, which facilitates the co-extrusion of different materials.

[0112] The difference between the die extrusion piece M5 and the die extrusion piece M3 is that the two are mirror images and the injection port directions are different.

[0113] After the above three-layer co-extrusion, the extruded template enters the cooling and shaping device for cooling to avoid surface deformation. The extruded plastic template blank is cooled by a vacuum cooling and shaping table to cool it down and solidify it to maintain a stable shape.

[0114] The cooled template is transferred to the cutting equipment through the traction device and cut into the required length;

[0115] Among them, the hot melt adhesive and PA co-extrusion die adopts a feed port structure set on the left and right sides respectively. The hot melt adhesive and PA can be melted and flowed in through the side holes designed by the die. And according to the needs, the flow channels of the combined die extrusion piece M5 and the die extrusion piece M3 can be designed as a one-to-two or two-to-four die, so that the hot melt adhesive and PA can reach the ends of the upper and lower flow channels of the die extrusion piece along the upper and lower flow channels respectively. The die extrusion piece M4 and the die extrusion piece M2 are designed to distribute the flow channels according to the actual cross-sectional shape of the die, and the distributed flow channels are uniformly distributed. Multi-channel design, hot melt adhesive and PA flow from the side inlet along the flow channels of die extrusion piece M5 and die extrusion piece M3 into the four flow channel openings on the back of die extrusion piece M4 and die extrusion piece M2, and then flow into the flow channels around the outer surface of the board through small tributaries of die extrusion piece M4 and die extrusion piece M2. After the hot melt adhesive enters the main template extrusion channel and is evenly distributed on the board surface, PA enters the main template surface with co-extruded hot melt adhesive, realizing the co-extrusion of three layers of materials, improving the wrapping effect and the performance of the board.

[0116] The processing temperature for PVC is between 160-190°C; the processing temperature for hot-melt adhesives is typically between 160-200°C; and the processing temperature for PA is between 240-280°C. The PVC residence time is kept shorter than the decomposition time to estimate the length of the flow through the area. The maximum area of ​​the product is used as the mold interface. The relationship between residence time and mold length, L, is calculated to be approximately 90.2L. The residence time, T, needs to be determined based on the ultimate thermal stability temperature of the PVC. It's known that PVC has a thermal stability of approximately 4 minutes at a reference temperature of 180°C. Using the Arrhenius kinetic model, the decomposition time at any temperature can be estimated. The calculated thermal stability times for PVC at 200°C are 122 seconds, 66 seconds at 220°C, and 28 seconds at 250°C. This conversion yields the maximum die lengths for the three temperatures to be 1.35m, 0.73m, and 0.31m, respectively. In a direct coextrusion solution, the die length L should be designed to be less than the maximum length at the corresponding temperature to prevent thermal degradation of the PVC. During the coating process, the PA melt first interacts with the active adhesive layer on the PVC surface through a dual "melt infiltration and chemical crosslinking" process. This occurs through an in-situ polymerization reaction between NCO groups and amino groups at the end of the PA molecular chains, forming a copolymer transition layer at the interface. This polyurethane adhesive layer provides a dual protective mechanism during the high-temperature coating process: chemical crosslinking strengthens the interfacial bonding while acting as a thermal barrier to slow the rate of heat transfer from the PA melt to the PVC substrate. The optimized design of the mold length and the thermal barrier function of the glue form a synergistic effect, which not only ensures the full progress of the in-situ polymerization reaction, but also effectively controls the risk of decomposition of the PVC substrate due to local overheating, and achieves a simultaneous improvement in the interface shear strength and thermal stability of the composite material.

[0117] The invention discloses an application of a preparation method of a co-extruded plastic formwork, and applies the preparation method of the co-extruded plastic formwork to the construction industry. Through the co-extrusion process, multiple performance requirements are achieved in a one-time molding process, and a good anti-sticking effect can be achieved after pouring concrete, making the plastic formwork easy to demould.

[0118] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0119] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A co-extruded plastic template, characterized by: The plastic template comprises an inner co-extrusion layer (1) and an outer surface co-extrusion layer (2) integrally formed with the inner co-extrusion layer (1). The plastic template is formed by using PVC as a base material and the outer surface is processed and formed by using a PA co-extrusion process. The plastic template is provided with side reinforcing ribs (3) of a hollow structure on both sides, and a plurality of intermediate reinforcing ribs (4) are arranged at intervals between the side reinforcing ribs (3). The intermediate reinforcing ribs (4) are provided with a hollow structure, and a sealing cover (5) is provided along the end of the intermediate reinforcing ribs (4) to form a sealed structure for the plastic template; A plurality of the plastic templates are provided, and the plurality of connected plastic templates are fixed along the longitudinal direction by connecting pieces.

2. The co-extruded plastic template according to claim 1, characterized in that: The inner co-extruded layer (1) is a co-extruded layer of PVC material, the outer surface co-extruded layer (2) is a co-extruded layer of PA material, the inner co-extruded layer (1) forms a plurality of independent spaced cavity structures (6), and the spaced cavity structures (6) are arranged in a through-type manner; The spacer cavity structure (6) includes internal longitudinal reinforcing ribs and internal cross beam ribs, the internal longitudinal reinforcing ribs and the internal cross beam ribs are co-extruded, and the internal cross beam ribs are a partition layer (7), and the partition layer (7) adopts a horizontal structure or has a broken line structure. The spacing between the internal longitudinal reinforcement ribs is controlled between 15mm-20mm, and the distance between the internal crossbeam ribs and the inner wall of the slab top on the concrete pouring side is between 7mm-9mm.

3. The co-extruded plastic template according to claim 1, characterized in that: The hollow support columns (8) are co-extruded in the spaced cavity structures (6) between the adjacent intermediate reinforcing ribs (4); A hollow support column (8) is provided in the middle reinforcing rib (4) at the same position as the spacer cavity structure; The plastic templates between adjacent intermediate reinforcement ribs (4) form an arc-shaped structure (9), the side reinforcement ribs (3) and the intermediate reinforcement ribs (4) are protrudingly arranged, and a supporting sealing plate (10) is provided inside the intermediate reinforcement ribs (4).

4. The co-extruded plastic template according to claim 3, characterized in that: The connecting member comprises a first connecting member (11) and a second connecting member (12), and a plurality of connected plastic templates are fixed along the longitudinal or transverse direction by the first connecting member (11) and / or the second connecting member (12).

5. The co-extruded plastic template according to claim 4, characterized in that: The side reinforcement ribs (3) on both sides of the plastic template are provided with mounting protrusions (13) that cooperate with the first connecting member (11); The sealing cover (5) of the plastic template is provided with a mounting protrusion (13) that cooperates with the first connecting member (11); The connection points of the sealing covers (5) connected to the plastic template are fixed by a first connecting member (11) and / or a second connecting member (12).

6. The co-extruded plastic template according to claim 4, characterized in that: The sealing cover (5) is provided with a mounting protrusion (13) and an extension plate (14) that cooperate with the intermediate reinforcement rib (4); the mounting protrusions (13) are arranged at intervals on the sealing cover (5), and the distance between the mounting protrusions (13) and adjacent intermediate reinforcement ribs (4) is the same; The extension plates (14) are located below the mounting protrusions (13). The extension plates (14) are spaced apart and arranged in an arc-shaped structure and are arranged horizontally. The extension plates (14) cooperate with the plastic templates between the adjacent intermediate reinforcing ribs (4) to form an arc-shaped structure (9). The extension plate (14) cooperates with a plurality of independent spaced cavity structures formed by the internal co-extruded layer (1), and the extension plate (14) penetrates into the inner side of the extruded spaced cavity structure and cooperates with the inner wall of the plastic template; The extension plate is bonded to the inner wall by a plurality of independent spaced cavity structures (6) formed by the internal co-extruded layer (1) using adhesive, and the sealing cover (5) is fastened to the connection hole on the middle reinforcing rib (4) on the outside by screws to form a whole; Or the sealing cover (5) is provided with spaced through holes.

7. The co-extruded plastic template according to claim 6, characterized in that: The first connecting member (11) comprises a body (11A), a forming cavity (11B) is provided on the body (11A), and symmetrical flange structures (11C) are provided along both sides of the bottom of the forming cavity (11B); The inner side of the molding cavity (11B) is provided with a forming groove (11D) that matches the plastic template, and the forming groove (11D) matches the arc protrusion on the plastic template; The body (11A) is further provided with a press-type structure (11E), and the press-type structure (11E) is in contact with the matching end surface of the adjacent plastic template; The forming groove (11D) is an arc-shaped groove structure, the forming groove (11D) is arranged at intervals up and down or is arranged alone, and the forming groove (11D) is a through groove structure symmetrically arranged along the inner wall of the forming cavity (11B); A plane structure is formed on the press-forming structure (11E), and a disassembly gap is formed between the plane structure formed on the press-forming structure (11E) and the molding cavity (11B).

8. The co-extruded plastic template according to claim 7, characterized in that: The second connecting member (12) includes a pin (12A) and a gasket (12B) fitted on the pin (12A), two gaskets (12B) are provided, and the gaskets (12B) are installed on both sides of the side reinforcing ribs (3) of adjacent plastic templates; A pin hole is provided at the end of the pin shaft (12A), a pin (12C) is provided in the pin hole, and the pin (12C) is provided in a wedge-shaped structure.

9. The method for preparing a co-extruded plastic template according to any one of claims 1 to 8, characterized in that: The following steps are included: The raw materials are mixed with additives to prepare PVC as base material and PA material particles; The raw materials are respectively put into a hot mixer for mixing, after dehumidification to remove moisture, discharged into a cold mixer, after removing foreign matter, into a storage tank, and homogenized to obtain a mixed material; Adjust the extruder parameters according to the product characteristics and process requirements; The inner layer PVC plastic particles and the middle layer hot melt adhesive particles and PA particles are added to different extruders respectively. The PVC plastic particles enter the main extruder, and the PA particles and the middle layer hot melt adhesive particles enter the co-extruder. After heating and melting, the co-extrusion distributor in the mold evenly distributes the materials of each layer and extrudes them together. Among them, PVC particles enter the main extruder and enter the multi-piece side-by-side die to be extruded into PVC profiles. Hot-melt adhesive particles enter the injection hole of the die extrusion piece M5 through the co-extruder on one side, are distributed to the four end points through the internal flow channel, enter the four-way hole of the die extrusion piece M4, and flow into the flow channel of the die extrusion piece M4 so that the liquid fluid formed by the hot-melt adhesive particles is evenly distributed to the surface of the PVC profile. PA particles enter the injection hole of the die extrusion piece M3 through the co-extruder on the other side, are distributed to the four end points through the internal flow channel, enter the four-way hole of the die extrusion piece M2, and flow into the flow channel of the die extrusion piece M2 so that the liquid fluid formed by the PA particles is evenly distributed to the surface of the PVC profile to co-extrude the hot-melt adhesive. During the co-extrusion process, each die piece is grooved on one side to form a flow channel, and the back is a flat structure. The flow channel cavity is formed by the flat structure of the front extrusion piece to achieve co-extrusion; After the above three-layer co-extrusion, the extruded template enters the cooling and shaping device for cooling to avoid surface deformation. The extruded plastic template blank is cooled by the vacuum cooling and shaping table to cool and solidify it to maintain a stable shape. The cooled template is transferred to the cutting equipment through the traction device and cut into the required length; Among them: the processing temperature of PVC is between 160-190℃; the processing temperature of hot melt adhesive is usually between 160-200℃; the processing temperature of PA is between 240-280℃.

10. An application of the method for preparing a co-extruded bio-based PA formwork according to claim 9, wherein the method for preparing a co-extruded plastic formwork according to claim 9 is applied in the construction industry. Through the co-extrusion process, multiple performance requirements are achieved in a single molding process, and after pouring concrete, a good anti-sticking effect can be achieved, making the plastic formwork easy to demold.

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