Graphene heat-insulating non-combustible board production device and production process

Abstract

This application discloses a production apparatus and process for graphene thermal insulation and non-combustible boards, belonging to the field of graphene insulation board preparation technology. The production apparatus includes a foaming agent storage tank, a black material storage tank, a white material storage tank, a catalyst storage tank, a flame retardant mixing tank, a flame retardant feed hopper, a buffer tank, a high-speed mixing chamber, an injection gun, a foaming mechanism, and a curing mechanism. This production apparatus uses a solid metering device to meter the flame retardant feed, which can improve the metering accuracy of the flame retardant and enhance the uniformity of board quality in batch production. Furthermore, the flame retardant and other raw materials are mixed in the high-speed mixing chamber before entering the foaming mechanism for foaming, which can improve the uniformity of flame retardant dispersion, thereby improving the uniformity of various properties of the board.

Description

Technical Field

[0001] This application relates to a production apparatus and process for a graphene thermal insulation and non-combustible board, belonging to the field of graphene insulation board preparation technology. Background Technology

[0002] Graphene-insulated non-combustible boards are homogeneous, highly insulating, and non-combustible insulation boards made by mixing polyurethane rigid foam as a matrix with graphene-coated flame retardants and other additives at a specific temperature, followed by catalysis, foaming, and curing processes. The boards have a fiber cloth interface layer and a closed-cell structure. Due to their advantages such as lightweight, flame retardancy, and high strength, they have gradually become a research focus for building insulation boards.

[0003] Currently, the production process of graphene thermal insulation and non-combustible boards involves mixing the various raw materials, then injecting them into a mold for foaming and curing. For example, patent CN106496518A provides a graphene-modified polyurethane insulation board, which premixes white material, graphene, and flame retardant to form a white material premix, and then foams it with black material in a high-pressure foaming agent to form a mixture, thereby obtaining an insulation board that combines thermal insulation and flame retardant properties. Another example is patent CN118440280A, which provides a method for preparing homogeneous insulation materials, which mixes polyol, additives, and flame retardant to obtain a mixed liquid, then adds diisocyanate, stirs, pours it into a mold for foaming and curing.

[0004] The two preparation methods described above are only suitable for experimental use. The raw materials can be mixed for a relatively long time before foaming and curing, resulting in minimal differences in the uniformity of the product's properties. However, in industrial production, to improve efficiency, the raw materials are often mixed quickly followed by foaming and curing. This results in a shorter mixing time. Since the flame retardant dosage in this board is relatively large, two problems arise: firstly, the short mixing time makes it difficult to ensure the uniformity of the raw material mixture; secondly, current flame retardant feeding methods use screw feeders, leading to inaccurate metering and poor uniformity in batch production. The dispersibility of the flame retardant not only affects flame retardant performance but also the uniformity and stability of the closed-cell structure formed by the foaming agent, thus causing instability in the product's mechanical properties, flame retardancy, and thermal insulation performance. Therefore, there is an urgent need for an industrially feasible production device and process to improve the uniformity of various properties of graphene thermal insulation non-combustible boards. Summary of the Invention

[0005] To address the aforementioned issues, a production apparatus and process for graphene heat-insulating and non-combustible boards are provided. This production apparatus uses a solid metering device to meter the flame retardant feed, which improves the metering accuracy of the flame retardant and enhances the uniformity of board quality in batch production. Furthermore, the flame retardant is mixed with other raw materials in a high-speed mixing chamber before entering the foaming mechanism for foaming, which improves the dispersion uniformity of the flame retardant and thus enhances the uniformity of various properties of the board.

[0006] According to one aspect of this application, an apparatus for producing a graphene heat-insulating and non-combustible panel is provided, comprising:

[0007] A foaming agent storage tank, wherein the foaming agent storage tank is used to contain foaming agent and is connected to a foaming agent metering device;

[0008] A black material storage tank, which is used to contain polyurethane black material and is connected to a black material metering device;

[0009] The white material storage tank is used to contain polyurethane white material and is connected to the white material metering device.

[0010] A catalyst storage tank, which is used to contain the catalyst and is connected to a catalyst metering device;

[0011] A flame retardant mixing tank, wherein the flame retardant mixing tank is used for mixing flame retardants;

[0012] A flame retardant feed hopper is provided, with the upper part of the flame retardant feed hopper connected to a flame retardant mixing tank via a first spiral feed pipe, and a solid metering device is provided below the flame retardant feed hopper.

[0013] A buffer tank, with an opening at the top and located at the discharge end of the solid metering device, and a second spiral feed pipe connected to the side wall of the buffer tank;

[0014] A high-speed mixing chamber, one side of which is connected to the outlet of the second spiral feed tube, and the other side of which is provided with an injection port;

[0015] The injection gun is located at one end of the high-speed mixing chamber away from the second spiral feed tube. The injection gun is used to inject a premix of foaming agent, white material, black material and catalyst into the high-speed mixing chamber through the injection port.

[0016] A foaming mechanism is disposed below the high-speed mixing chamber;

[0017] A curing mechanism for curing foamed graphene heat-insulating and non-combustible boards.

[0018] Optionally, it also includes a static mixer, the inlet of which is connected to a foaming agent metering device, a white material metering device, and a catalyst metering device for mixing the foaming agent, white material, and catalyst. The outlet of the static mixer is connected to a first inlet of the injection gun, and the black material metering device is connected to a second inlet of the injection gun.

[0019] Optionally, it also includes a temperature control component for controlling the temperature of the high-speed mixing chamber.

[0020] According to a second aspect of this application, a manufacturing process for a graphene heat-insulating and non-combustible board is provided, comprising the following steps:

[0021] (1) The catalyst storage tank, foaming agent storage tank, black material storage tank and white material storage tank respectively deliver the catalyst, foaming agent, black material and white material into the injection gun to obtain premixed material. The premixed material enters the high-speed mixing chamber through the injection port of the injection gun. The white material storage tank contains 0.8-1.5wt% water and 0.3-1wt% silicone oil.

[0022] (2) The flame retardant enters the flame retardant feed hopper from the flame retardant mixing tank, then enters the buffer tank through the solid metering device, and then flows out of the buffer tank through the second spiral feed pipe to the high-speed mixing chamber to mix with the premixed material to obtain the mixture.

[0023] (3) The mixture is discharged from the outlet of the high-speed mixing chamber to the foaming mechanism for foaming to obtain a board to be cured;

[0024] (4) The board to be cured is transported to the curing mechanism and cured at 40-60°C for at least 2 hours to obtain the graphene heat-insulating and non-combustible board.

[0025] In the above production process, the solid metering device is preferably a belt scale, which is set below the flame retardant feed hopper. Since the distance between the outlet of the flame retardant feed hopper and the belt scale is known and the relative position remains unchanged, the flame retardant can be evenly and completely distributed on the belt scale as it rotates. That is, the height of the flame retardant on the belt scale remains unchanged. By pre-testing the density of the flame retardant, the amount of flame retardant fed per unit time can be calculated. This process control can improve the accuracy of the flame retardant metering and feeding, thereby improving the quality uniformity of the boards produced in batches.

[0026] Optionally, the weight ratio of the catalyst, foaming agent, black component, white component and flame retardant is (0.2-1.5):(15-20):(95-110):80:(380-440);

[0027] The foaming agent, white material, and catalyst are first mixed in a static mixer, and then mixed with the black material in a dispensing gun to obtain the premix.

[0028] The foaming agent, white material, and catalyst are mixed in a static mixer, which improves the mixing uniformity of the above raw materials. This allows the foaming agent to be dispersed first in the intermediate system and then dispersed from the intermediate system into the overall system. This facilitates the uniform dispersion of the foaming agent in the overall material, thereby improving the uniformity of foaming and thus improving the performance uniformity of the graphene thermal insulation and non-combustible board.

[0029] Optionally, the temperature of the high-speed mixing chamber in step (2) is 26–35°C.

[0030] To prevent the foaming agent from foaming prematurely, the temperature of the high-speed mixing chamber is usually controlled below 25°C. In this application, the temperature of the high-speed mixing chamber is maintained at 26-35°C by a temperature control component. This setting allows the foaming agent to take effect in advance, forming a material with lower viscosity and better flowability. This ensures smoother material feeding into the high-speed mixing chamber and avoids material jamming. It also improves the mixing uniformity of all raw materials, thereby enhancing the performance uniformity of the graphene heat-insulating and non-combustible board at various locations.

[0031] Optionally, the foaming temperature in the foaming mechanism in step (3) is 50-70°C, preferably 60°C.

[0032] The above foaming conditions can improve the foaming uniformity of the foaming agent, which facilitates the formation of a uniform and stable closed-cell structure in the graphene heat-insulating non-combustible board, and ensures that the flame retardant can be uniformly coated in the closed-cell structure.

[0033] Optionally, the flame retardant is selected from graphene oxide-coated inorganic flame retardants and modified expandable graphite in a weight ratio of 1:(0.5-0.8), wherein the modified expandable graphite is obtained by modifying protocatechuic acid expandable graphite.

[0034] By using the two flame retardants mentioned above in combination, the mechanical properties and thermal stability of the board can be improved while enhancing its flame retardancy, without adversely affecting the thermal conductivity of the board.

[0035] Optionally, the modification step of the modified expandable graphite is as follows: the expandable graphite is placed in a protocatechuic acid solution and immersed at 40-50°C for 30 minutes, and then transferred to a microwave dryer for drying. The weight ratio of expandable graphite to protocatechuic acid solution is 1:(3-5), and the concentration of protocatechuic acid in the protocatechuic acid solution is 0.5-0.9 mg / ml.

[0036] Currently, flame retardants are either encapsulated within the foam cells formed by the foaming agent or partially embedded between the cells, so the amount of flame retardant used cannot affect the thermal conductivity of the board. However, due to the influence of gravity, the flame retardant will settle to varying degrees during the foaming process after being mixed with other raw materials, resulting in significant performance differences between the upper and lower parts of the board. This not only affects the board's mechanical, thermal insulation, and flame retardant properties but also weakens the adhesion between the lower part of the board and the underlying carbon fiber felt, thus impacting the board's actual performance.

[0037] In this application, protocatechuic acid is used to surface-modify expandable graphite, allowing the protocatechuic acid to be loaded onto the surface of the graphite. Because protocatechuic acid contains hydroxyl and carboxyl groups, it can interact with isocyanate in the initial stage, preventing the sedimentation of the expandable graphite. Furthermore, in the later stages of the reaction, the hydroxyl groups in protocatechuic acid can partially participate in the polyurethane reaction, resulting in uniform dispersion of the expandable graphite in the polyurethane system. Graphene is used to coat the inorganic flame retardant. Graphene includes hydroxyl, carboxyl, and epoxy groups, which can also interact with isocyanate in the initial stage, preventing the sedimentation of the inorganic flame retardant. Simultaneously, a small amount of hydroxyl groups in graphene also participate in the reaction, ensuring uniform dispersion of the inorganic flame retardant in the polyurethane system. This flame retardant treatment improves the performance uniformity of the board and enhances the adhesion between the board and carbon fiber felt.

[0038] Furthermore, this study also found that protocatechuic acid contains phenolic hydroxyl groups, which can help graphite form a stable carbon layer at high temperatures, improving flame retardancy and thermal stability. Simultaneously, because expandable graphite can be uniformly distributed within the board, it can also help improve the mechanical properties of the board. However, due to the hydroxyl groups in protocatechuic acid, it can participate in the reaction of polyurethane. Excessive use can affect the crosslinking degree of the polyurethane material; therefore, it is necessary to control the concentration of protocatechuic acid and the amount of protocatechuic acid solution used.

[0039] Optionally, the flame retardant feed hopper is also provided with a silicone oil inlet. After the silicone oil and flame retardant are mixed evenly in the flame retardant feed hopper, they are discharged onto the solid metering device. The silicone oil accounts for 0.3wt% to 1wt% of the amount of flame retardant used.

[0040] Incorporating a silicone oil inlet within the flame retardant feed hopper increases the silicone oil content in the graphene insulation non-combustible board. Although the amount of silicone oil added to the flame retardant feed hopper is relatively small, it has been found that it can wet the flame retardant during the mixing process, acting as a lubricant and improving the uniformity of the flame retardant feed into the high-speed mixing chamber, thereby enhancing the performance uniformity of the board. Furthermore, this silicone oil and the silicone oil added to the white component work together: firstly, it refines the cell structure during the foaming process of the foaming agent, further reducing the thermal conductivity of the board; secondly, it stabilizes the cell interface and maintains the stability of the cell structure after foaming.

[0041] The beneficial effects of this application include, but are not limited to:

[0042] 1. The production apparatus for graphene heat-insulating and non-combustible boards according to this application can improve the metering accuracy of flame retardant by setting a solid metering device, thereby improving the quality uniformity of the boards produced in batches.

[0043] 2. The production apparatus for graphene heat-insulating and non-combustible boards according to this application has a temperature control component that can control the reaction temperature of the high-speed mixing chamber, so that the raw materials can be pre-foamed in the high-speed mixing chamber, which facilitates the feeding of materials and improves the uniformity of foaming.

[0044] 3. The production process of the graphene heat-insulating and non-combustible board according to this application can improve the dispersibility of flame retardant in raw materials in a short time, making it more suitable for industrial production, reducing the production time of the graphene heat-insulating and non-combustible board, and improving production efficiency.

[0045] 4. According to the production process of the graphene heat-insulating non-combustible board of this application, the combination of feeding and mixing methods and foaming process can suppress the settling of flame retardants and improve the dispersion uniformity of flame retardants during the foaming process, thereby improving the uniformity and stability of the cell structure in the non-combustible board, so as to obtain a non-combustible board with good uniformity of various properties. Attached Figure Description

[0046] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0047] Figure 1 This is a schematic diagram of the production apparatus for the graphene heat-insulating and non-combustible board involved in Embodiment 1 of this application;

[0048] Figure 2 This is a schematic diagram of the structure of each raw material feeding, mixing and foaming mechanism of the production device for graphene heat-insulating and non-combustible board according to Embodiment 1 of this application.

[0049] Figure 3 This is a side view of the feeding interface, conveyor belt, and upper pressure plate involved in Embodiment 1 of this application;

[0050] Figure 4 This is a cross-sectional view of the high-speed mixing chamber and injection gun involved in Embodiment 1 of this application.

[0051] List of components and reference numerals:

[0052] 10. Foaming agent storage tank; 11. Foaming agent metering device; 20. Black material storage tank; 21. Black material metering device; 30. White material storage tank; 31. White material metering device; 40. Catalyst storage tank; 41. Catalyst metering device; 50. Flame retardant mixing tank; 51. Flame retardant feed hopper; 52. First spiral feed pipe; 53. Belt scale; 54. Buffer tank; 55. Second spiral feed pipe; 60. High-speed mixing chamber; 61. High-speed agitator; 70. Injection gun; 701. First inlet; 702. Second inlet; 71. Static mixer; 81. Connecting pipe; 82. Discharge interface; 83. Support rod; 84. Frame; 85. Upper conveyor belt; 86. Lower conveyor belt; 87. Receiving plate. Detailed Implementation

[0053] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0054] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased commercially. The black component is hexamethylene diisocyanate, the white component is a mixture of polyether tetraol (hydroxyl value of 400 mg KOH / g) and polyacrylate polyol (hydroxyl value of 650 mg KOH / g) in a weight ratio of 3:1, the foaming agent is pentane, the catalyst is dibutyltin dilaurate, and the silicone oil is polydimethylsiloxane.

[0055] Unless otherwise specified, the methods used in the embodiments of this application are conventional methods in the prior art.

[0056] Example 1

[0057] refer to Figure 1-4 This embodiment relates to a production apparatus for graphene heat-insulating and non-combustible panels, comprising:

[0058] A foaming agent storage tank 10 is used to contain foaming agent and is connected to a foaming agent metering device 11;

[0059] Black material storage tank 20, which is used to contain polyurethane black material and is connected to black material metering device 21;

[0060] White material storage tank 30, which is used to contain polyurethane white material and is connected to white material metering device 31;

[0061] Catalyst storage tank 40, which is used to contain catalyst and is connected to catalyst metering device 41;

[0062] Flame retardant mixing tank 50, the flame retardant mixing tank 50 being used for mixing flame retardants;

[0063] Flame retardant feed hopper 51, the upper part of which is connected to flame retardant mixing tank 50 through first spiral feed pipe 52, and a solid metering device is provided below the flame retardant feed hopper 51;

[0064] A buffer tank 54 is provided with an opening at the top and is located at the discharge end of the solid metering device. A second spiral feed pipe 55 is connected to the side wall of the buffer tank 54.

[0065] A high-speed mixing chamber 60 is provided, one side of which is connected to the outlet of the second spiral feed tube 55, and the other side of which is provided with an injection port.

[0066] Injection gun 70 is located at one end of high-speed mixing chamber 60 away from the second spiral feed tube 55. The injection gun 70 is used to inject premixed materials of foaming agent, white material, black material and catalyst into high-speed mixing chamber 60 through injection port.

[0067] A foaming mechanism is disposed below the high-speed mixing chamber 60;

[0068] A curing mechanism for curing foamed graphene heat-insulating and non-combustible boards.

[0069] Figure 1 and Figure 2 The diagram shows a front view; the foaming mechanism is not shown. The flame retardant feeding method for the aforementioned production device is as follows: different types of flame retardants are mixed in a flame retardant mixing tank 50, and then conveyed through a first spiral feed pipe 52 to a flame retardant feed hopper 51. The flame retardant feed hopper 51 is equipped with a stirring mechanism to prevent flame retardant from adhering to the walls and further improve the mixing uniformity. Afterwards, the mixture passes through a discharge port below the flame retardant feed hopper 51, is metered by a solid metering device, and then enters a buffer tank 54 for buffering. Finally, it is conveyed through a second spiral feed pipe 55 to the high-speed mixing chamber 60. This method enables precise metering of the flame retardant, facilitates continuous industrial production, and improves the performance consistency of the graphene thermal insulation non-combustible panels obtained through continuous production.

[0070] In the aforementioned production apparatus, the flame retardant is fed from one side of the high-speed mixing chamber 60, while the premixed materials of foaming agent, white material, black material, and catalyst are fed from the other side of the high-speed mixing chamber 60 through the injection gun 70. A high-speed agitator 61 is installed in the high-speed mixing chamber 60, and its high-speed rotation ensures that all raw materials are uniformly mixed within the chamber, improving production efficiency. After mixing in the high-speed mixing chamber 60, the material is discharged from the discharge port below the chamber to the foaming mechanism for foaming. The foamed board to be cured is then cured by the curing mechanism to obtain the graphene heat-insulating and non-combustible board.

[0071] Specifically, the speed of the high-speed mixer 61 can be set according to actual needs, for example, it can be set to 1500-3000 rpm.

[0072] Specifically, the solid metering device is a belt scale 53. The flame retardant is fed onto the belt scale 53 from the discharge port below the flame retardant feed hopper 51. No baffle is installed at the discharge port, so the area between the discharge port and the belt scale 53 is filled with flame retardant material. Therefore, the material height conveyed from the discharge port to above the belt scale 53 is consistent. By combining the conveying speed of the belt scale 53 and the density of the flame retardant, the amount of flame retardant conveyed per unit time can be calculated. In this method, the belt scale 53 can have its own metering component for accurate weighing of the flame retardant, or it can be used without an additional metering component, relying solely on the conveying speed of the belt scale 53 to calculate the amount of flame retardant used, thus reducing the manufacturing cost of the production device.

[0073] Specifically, if the required width of the graphene thermal insulation and non-combustible board is narrow, the discharge port of the high-speed mixing chamber 60 can be fixed directly to the mold position of the foaming mechanism. The raw material discharged from the high-speed mixing chamber 60 will foam at this position to obtain the board of the required size. No additional components are needed to disperse the raw material discharged from the high-speed mixing chamber 60 to different positions of the board. If the required width of the graphene thermal insulation and non-combustible board is wide, if the position of the raw material discharged from the high-speed mixing chamber 60 in the mold of the foaming mechanism remains unchanged, it will be difficult for the raw material to self-level to both sides of the board, resulting in a large difference in the performance of the board in the width direction.

[0074] Therefore, in a preferred embodiment, the foaming mechanism includes a connecting pipe 81, a discharge port 82, and a support rod 83. The connecting pipe 81 is a flexible hose and is used to connect the high-speed mixing chamber 60 and the discharge port 82. The discharge port 82 has openings at both the top and bottom. The discharge port 82 is mounted on the support rod 83 and can move along the support rod 83. The support rod 83 is mounted above the mold of the foaming mechanism and extends from the width direction of the graphene heat-insulating and non-combustible board.

[0075] In this configuration, since the connecting pipe 81 is a flexible tube, when the discharge port 82 moves along the support rod 83, the connecting pipe 81 can always ensure the connection between the high-speed mixing chamber 60 and the discharge port 82. Therefore, through the configuration of the connecting pipe 81 and the discharge port 82, it is possible to uniformly discharge the graphene heat-insulating and non-combustible board in the width direction, improve the positional uniformity of the initial raw materials, and facilitate the production of large-size graphene heat-insulating and non-combustible boards.

[0076] Specifically, the way the feeding interface 82 moves along the support rod 83 is not limited. For example, a groove can be set on the support rod 83, and a slider that cooperates with the groove can be set at the feeding interface 82. The slider can be driven to slide on the groove by electromagnetic drive. Alternatively, a gear can be set on the feeding interface 82, and a rack that cooperates with the gear can be set on the support rod 83. The motor drives the gear to move along the rack, so as to realize the movement of the feeding interface 82 along the support rod 83.

[0077] For details, please refer to Figure 3 , Figure 3 The arrow indicates the forward direction of non-combustible board production. The foaming mechanism includes a frame 84, an upper conveyor belt 85, a lower conveyor belt 86, and a receiving plate 87. The receiving plate 87 is located below the discharge interface 82. The upper conveyor belt 85 and the lower conveyor belt 86 are arranged parallel to each other on the frame 84. The upper conveyor belt 85 is located below the lower conveyor belt 86, and the lower conveyor belt 86 is located on one side of the receiving plate 87 (close to the forward direction of non-combustible board production). The upper conveyor belt 85 and the lower conveyor belt 86 form the foaming cavity. During production, a layer of fiberglass felt is laid below the upper conveyor belt 85 and above the lower conveyor belt 86. The fiberglass felt laid on the lower conveyor belt 86 extends to below the discharge port 82 and is located above the receiving plate 87. The mixture discharged from the discharge port 82 falls onto the fiberglass felt laid on the lower conveyor belt 86. As the conveyor belt moves forward, it carries the mixture into the foaming mold cavity of the upper conveyor belt 85 and the lower conveyor belt 86. Foaming is achieved under the heating of the upper conveyor belt 85 and the lower conveyor belt 86, thus enabling continuous production.

[0078] Since the distance between the upper and lower conveyor belts remains constant, they form the space after the board is foamed. To improve foaming uniformity, board strength, board formability, and dimensional stability, the foaming time of the board by the upper conveyor belt 85 and the lower conveyor belt 86 is at least 90 seconds. Therefore, the lengths of the upper conveyor belt 85 and the lower conveyor belt 86 can be set according to the forward speed. The upper conveyor belt 85 and the lower conveyor belt 86 are made of metal and have built-in heating mechanisms. Heating of the upper conveyor belt 85 and the lower conveyor belt 86 through their built-in heating mechanisms controls the foaming temperature of the board. In this application, the controlled foaming temperature is 50-70℃.

[0079] Specifically, after the graphene thermal insulation and non-combustible board is foamed by the self-foaming mechanism, it is then transported to the curing mechanism for curing. Since the foaming mechanism is a continuous production process, the board size obtained from the self-foaming mechanism is relatively large. Therefore, a board cutting mechanism can be set to cut the board into appropriate sizes. A drying mechanism can also be set to pre-dry the cut board before transferring it to the curing mechanism for curing. The production process of polyurethane rigid foam materials in the prior art can be referred to here, which does not constitute a limitation on this production device.

[0080] Specifically, the curing mechanism of this application can also adopt a common structure in the prior art. For example, the board can be transported into the curing chamber and the temperature of the curing chamber can be controlled. A continuous conveying mechanism can also be used during the transport process to ensure that the curing time of each board in the curing mechanism is consistent, thereby improving the performance consistency of the board.

[0081] In one embodiment, the production apparatus further includes a static mixer 71, the inlet of which is connected to the foaming agent metering device 11, the white material metering device 31 and the catalyst metering device 41, for mixing the foaming agent, white material and catalyst. The outlet of the static mixer 71 is connected to the first inlet 701 of the injection gun 70, and the black material metering device 21 is connected to the second inlet 702 of the injection gun 70.

[0082] refer to Figure 2 and Figure 4 In this configuration, the outlet of the static mixer 71 is connected to the second inlet 702 of the injection gun 70, and the first inlet 701 of the injection gun 70 is connected to the black material metering device 21. Therefore, mixing of all raw materials except the flame retardant in the injection gun 70 is possible. The static mixer 71 enables pre-mixing of the foaming agent, white material, and catalyst, and preliminary dilution of the foaming agent and catalyst, facilitating their uniform distribution in the final material. This improves the foaming uniformity of the board and enhances its overall performance.

[0083] As one implementation, a temperature control component is also included, which is used to control the temperature of the high-speed mixing chamber 60. The temperature control component enables temperature control of the high-speed mixing chamber 60, allowing only pre-foaming to be achieved, preventing the foaming agent from foaming completely within the high-speed mixing chamber 60, and improving the uniformity of the raw material mixing.

[0084] Specifically, the temperature control component can be a cooling channel located inside the side wall of the high-speed mixing chamber 60, or a cooling pipe wrapped around the outside of the high-speed mixing chamber 60. As long as it can allow cooling medium (cooling water or cooling air) to be introduced into it, it can achieve the functions of cooling and temperature control.

[0085] Example 2

[0086] This embodiment relates to a production process for a graphene heat-insulating and non-combustible board, which is carried out using the production apparatus of Embodiment 1, and includes the following steps:

[0087] (1) The catalyst storage tank, the foaming agent storage tank and the white material storage tank respectively deliver the catalyst, the foaming agent and the white material to the static mixer to obtain intermediate material. Then the intermediate material is mixed with the black material to obtain premix. The premix enters the high-speed mixing chamber through the injection port. The white material storage tank contains 0.8-1.5wt% water and 0.3-1wt% silicone oil.

[0088] (2) Inorganic flame retardant coated with graphene oxide and modified expandable graphite in a weight ratio of 1:(0.5-0.8) are first mixed in a flame retardant mixing tank, and then fed into the flame retardant feed hopper through the first spiral feed pipe. After that, the mixture is fed into the buffer tank through the belt scale, and then flows out of the buffer tank through the second spiral feed pipe to the high-speed mixing chamber to be mixed with the premixed material to obtain a mixture. The weight ratio of catalyst, foaming agent, black material, white material and flame retardant in the mixture is (0.2-1.5):(15-20):(95-110):80:(380-440). The temperature of the high-speed mixing chamber is 26-35℃.

[0089] (3) The mixture is discharged from the outlet of the high-speed mixing chamber to the foaming mechanism and foamed at 50-70°C to obtain a board to be cured;

[0090] (4) The board to be cured is transported to the curing mechanism and cured at 40-60°C for at least 2 hours to obtain the graphene heat-insulating and non-combustible board.

[0091] The modified expandable graphite is prepared by placing the expandable graphite in a protocatechuic acid solution and immersing it at 40-50°C for 30 minutes. Then, it is transferred to a microwave dryer for drying. The weight ratio of expandable graphite to protocatechuic acid solution is 1:(3-5), and the concentration of protocatechuic acid in the protocatechuic acid solution is 0.5-0.9 mg / ml.

[0092] Preferably, the flame retardant feed hopper is also provided with a silicone oil inlet. The silicone oil and flame retardant are mixed evenly in the flame retardant feed hopper and then discharged onto the belt scale. The silicone oil accounts for 0.3wt% to 1wt% of the amount of flame retardant used.

[0093] Graphene heat-insulating and non-combustible boards #1 to #8 with a thickness of 15 cm were prepared according to the above preparation method. The inorganic flame retardant coated with graphene oxide and the modified expandable graphite were prepared in advance before production. The preparation method of the inorganic flame retardant coated with graphene oxide in step (2) is as follows:

[0094] S1: Magnesium oxide and triisostearoyl titanate isopropyl ester with a weight ratio of 10:1 are added to a wet sand mill, and pulverized and modified once using 2mm zirconium balls. After spray drying, the powder is obtained. The powder is then pulverized and sieved through an air jet mill to obtain a modified inorganic flame retardant with a particle size of 500nm.

[0095] S2: The modified inorganic flame retardant was milled twice with 0.3mm zirconium balls and then added to a graphene oxide solution with a concentration of 0.7% and a weight ratio of 50:1 between the modified inorganic flame retardant and the graphene oxide solution. The mixture was treated at 30℃ for 120 minutes and then spray-dried to obtain a graphene oxide-coated modified inorganic flame retardant.

[0096] The other specific preparation methods are as follows:

[0097] Graphene heat-insulating and non-combustible panel #1

[0098] (1) The catalyst storage tank, the foaming agent storage tank and the white material storage tank respectively deliver the catalyst, the foaming agent and the white material to the static mixer to obtain intermediate material. Then the intermediate material is mixed with the black material to obtain premix. The premix enters the high-speed mixing chamber through the injection port of the injection gun. The white material storage tank contains 0.8wt% water and 1wt% silicone oil.

[0099] (2) Graphene oxide-coated inorganic flame retardant and modified expandable graphite, in a weight ratio of 1:0.5, are first mixed in a flame retardant mixing tank. Then, the mixture is fed into a flame retardant feed hopper through a first spiral feed pipe. The flame retardant feed hopper also has a silicone oil inlet. After the silicone oil and flame retardant are evenly mixed in the flame retardant feed hopper, they are discharged onto a belt scale. The silicone oil accounts for 0.3 wt% of the flame retardant. The mixture of flame retardant and silicone oil is fed into a buffer tank via the belt scale, and then flows out of the buffer tank through a second spiral feed pipe to the high-speed feed hopper. The mixture is prepared by mixing the premixed material in the mixing chamber to obtain a mixture. The weight ratio of catalyst, foaming agent, black material, white material and flame retardant in the mixture is 0.2:15:95:80:380. The temperature of the high-speed mixing chamber is 35℃. The modified expandable graphite is prepared by placing the expandable graphite in a protocatechuic acid solution and immersing it at 50℃ for 30 minutes. Then it is transferred to a microwave dryer for drying. The weight ratio of expandable graphite to protocatechuic acid solution is 1:3. The concentration of protocatechuic acid in the protocatechuic acid solution is 0.9 mg / ml.

[0100] (3) The mixture is discharged from the outlet of the high-speed mixing chamber to the foaming mechanism and foamed at 70°C to obtain a board to be cured;

[0101] (4) The plate to be cured is transported to the curing mechanism and cured at 60°C for 2 hours to obtain the product.

[0102] Graphene heat-insulating and non-combustible board #2

[0103] (1) The catalyst storage tank, the foaming agent storage tank and the white material storage tank respectively deliver the catalyst, the foaming agent and the white material to the static mixer to obtain intermediate material. Then the intermediate material is mixed with the black material to obtain premix. The premix enters the high-speed mixing chamber through the injection port of the injection gun. The white material storage tank contains 1.5wt% water and 0.3wt% silicone oil.

[0104] (2) Graphene oxide-coated inorganic flame retardant and modified expandable graphite, in a weight ratio of 1:0.8, are first mixed in a flame retardant mixing tank. Then, the mixture is fed into a flame retardant feed hopper through a first spiral feed pipe. The flame retardant feed hopper also has a silicone oil inlet. After the silicone oil and flame retardant are evenly mixed in the flame retardant feed hopper, the mixture is discharged onto a belt scale. The silicone oil accounts for 1.0 wt% of the amount of flame retardant used. The mixture of flame retardant and silicone oil is fed into a buffer tank via the belt scale, and then flows out of the buffer tank through a second spiral feed pipe to a high-speed mixing tank. The mixture is prepared by mixing the premixed material in the mixing chamber to obtain a mixture. The weight ratio of catalyst, foaming agent, black material, white material and flame retardant in the mixture is 1.5:20:110:80:440. The temperature of the high-speed mixing chamber is 26℃. The modified expandable graphite is prepared by placing the expandable graphite in a protocatechuic acid solution and immersing it at 40℃ for 30 minutes. Then it is transferred to a microwave dryer for drying. The weight ratio of expandable graphite to protocatechuic acid solution is 1:5. The concentration of protocatechuic acid in the protocatechuic acid solution is 0.5mg / ml.

[0105] (3) The mixture is discharged from the outlet of the high-speed mixing chamber to the foaming mechanism and foamed at 50°C to obtain a board to be cured;

[0106] (4) The plate to be cured is transported to the curing mechanism and cured at 40°C for 2.5 hours to obtain the product.

[0107] Graphene heat-insulating and non-combustible panel #3

[0108] The difference between it and graphene heat-insulating and non-combustible board 1# is that the temperature of the high-speed mixing chamber is 20℃, while the rest is the same as graphene heat-insulating and non-combustible board 1#.

[0109] Graphene heat-insulating and non-combustible panel #4

[0110] The difference between this and graphene heat-insulating and non-combustible board #1 is that the modified expandable graphite is replaced with unmodified expandable graphite, while the rest is the same as graphene heat-insulating and non-combustible board #1.

[0111] Graphene heat-insulating and non-combustible board #5

[0112] The difference between this and graphene heat-insulating and non-combustible board 1# is that the concentration of protocatechuic acid in the protocatechuic acid solution during the preparation of modified expandable graphite is 1.1 mg / ml, while the rest is the same as graphene heat-insulating and non-combustible board 1#.

[0113] Graphene heat-insulating and non-combustible board #6

[0114] The difference between this and graphene heat-insulating non-combustible board #1 is that the inorganic flame retardant coated with graphene oxide is replaced with untreated magnesium oxide; otherwise, they are the same as graphene heat-insulating non-combustible board #1.

[0115] Graphene heat-insulating and non-combustible panel #7

[0116] The difference between this and graphene heat-insulating and non-combustible board #1 is that silicone oil is not added through the hopper inlet; otherwise, they are the same.

[0117] Graphene heat-insulating and non-combustible board #8

[0118] The difference between this and graphene heat-insulating and non-combustible board #1 is that silicone oil is added through a separate metering tank and mixed with catalyst, foaming agent and white material in a static mixer to obtain intermediate material. The rest is the same as graphene heat-insulating and non-combustible board #1.

[0119] Graphene heat-insulating and non-combustible board #9

[0120] The difference between this and graphene heat-insulating and non-combustible board #1 is that the foaming agent, white material, and catalyst are not mixed in the static mixer and directly enter the second inlet, while the black material directly enters the first inlet. The foaming agent, white material, catalyst, and black material are all mixed in the injection gun and then enter the high-speed mixing chamber through the injection port. The rest is the same as graphene heat-insulating and non-combustible board #1.

[0121] Test Example 1

[0122] The thermal conductivity (15cm thickness), flame retardancy and mechanical properties of the graphene thermal insulation non-combustible board prepared in Example 2 were tested. The results are shown in Table 1 below. The flame retardancy performance was performed in accordance with GB8624-2012 standard.

[0123] Table 1

[0124]

[0125] Test Example 2

[0126] The 15cm thick graphene thermal insulation and non-combustible board prepared in Example 2 was cut and sampled, and laterally cut into 5cm thick upper, middle, and lower layers. The thermal conductivity of the upper, middle, and lower layers was tested respectively to obtain their respective thermal conductivity. The thermal conductivity deviation between the middle and upper layers and between the lower and upper layers was calculated. The thermal conductivity deviation between the middle and upper layers = |thermal conductivity of the middle layer - thermal conductivity of the upper layer|, and the thermal conductivity deviation between the lower and upper layers = |thermal conductivity of the lower layer - thermal conductivity of the upper layer|. The test results are shown in Table 2. In Table 2, the smaller the values ​​of the thermal conductivity deviation between the middle and upper layers and between the lower and upper layers, the better the uniformity of the graphene thermal insulation and non-combustible board in terms of thermal conductivity.

[0127] Table 2

[0128]

[0129] Test Example 3

[0130] The 15cm thick graphene thermal insulation and non-combustible board prepared in Example 2 was cut and sampled, and laterally cut into 5cm thick upper, middle and lower layers. The compressive strength of the upper, middle and lower layers was tested respectively to obtain their respective compressive strengths. The compressive strength deviations between the middle and upper layers and between the lower and upper layers were calculated. The compressive strength deviation between the middle and upper layers = |compressive strength of the middle layer - compressive strength of the upper layer|, and the compressive strength deviation between the lower and upper layers = |compressive strength of the lower layer - compressive strength of the upper layer|. The test results are shown in Table 2. In Table 3, the smaller the values ​​of the compressive strength deviations between the middle and upper layers and between the lower and upper layers, the better the uniformity of the mechanical strength of the graphene thermal insulation and non-combustible board.

[0131] Table 3

[0132]

[0133] As can be seen from the above tests, the graphene thermal insulation and non-combustible board prepared in this application has good thermal insulation, flame retardancy and mechanical strength, which can meet the requirements of building use.

[0134] A comparison of graphene heat-insulating and non-combustible board 1# and graphene heat-insulating and non-combustible board 3# shows that when the temperature of the high-speed mixing chamber decreases, the material is not pre-foamed in the high-speed mixing chamber, and the fluidity of the material discharged from the high-speed mixing chamber decreases slightly. Although the overall thermal conductivity of the board remains unchanged, the overall compressive strength of the board decreases significantly. Furthermore, due to the decrease in fluidity, the uniformity of the bubbles formed by the foaming agent decreases during the foaming process. Therefore, the deviation values ​​of thermal conductivity between the middle layer, the lower layer, and the upper layer in Table 2 increase, and the deviation values ​​of compressive strength between the middle layer, the lower layer, and the upper layer in Table 3 also increase.

[0135] A comparison of graphene thermal insulation and non-combustible board #1, #4, and #6 reveals that when the expandable graphite surface does not contain protocatechuic acid or the inorganic flame retardant surface is not coated with graphene oxide, the interlayer thermal conductivity and interlayer compressive strength deviations of the board increase significantly, especially between the lower and upper layers. This is because expandable graphite without protocatechuic acid and magnesium oxide flame retardant without graphene oxide coating will settle during the foaming process, resulting in a lower flame retardant content in the upper layer and a higher flame retardant content in the lower layer. This, in turn, affects the foaming process and the structure of the foam cells after foaming, thus indirectly affecting the overall thermal conductivity and compressive strength.

[0136] A comparison of graphene thermal insulation and non-combustible board #1 and graphene thermal insulation and non-combustible board #5 shows that an increase in the concentration of protocatechuic acid leads to an increase in the amount of protocatechuic acid on the surface of expandable graphite, resulting in an increase in thermal conductivity and a decrease in compressive strength. Furthermore, the uniformity of thermal conductivity and compressive strength also decreases. The reason for this is that an increase in the content of protocatechuic acid on the surface of expandable graphite increases the amount of protocatechuic acid participating in the formation of the polyurethane network, resulting in a denser polyurethane network. This reduces the foaming space of the foaming agent, leading to an increase in thermal conductivity. It also reduces the coverage of the expandable graphite by the closed-cell structure, resulting in exposed flame retardant on the microstructure of the board, causing instability in the cell structure, and consequently, a decrease in compressive strength, as well as a decrease in the uniformity of thermal insulation and mechanical strength.

[0137] A comparison of graphene thermal insulation non-combustible board 1# and graphene thermal insulation non-combustible board 7# shows that when silicone oil is not added through the hopper inlet, the silicone oil cannot play a lubricating role in the feeding of flame retardant. As a result, the uniformity of flame retardant feeding decreases, and it cannot stabilize the foamed cells. Therefore, the thermal insulation, mechanical strength, thermal insulation uniformity, and mechanical strength uniformity of the board all decrease.

[0138] A comparison of graphene heat-insulating and non-combustible board 1#, 7#, and 8# reveals that when silicone oil is added via a separate metering tank, it still plays a stabilizing role in the foam cells during and after foaming. Therefore, graphene heat-insulating and non-combustible board 8# exhibits better performance than 7#, but its performance is still lower than that of graphene heat-insulating and non-combustible board 1#. The reason for this may be that the silicone oil is combined with the flame retardant in a high-speed mixing chamber. Compared to mixing the silicone oil with the flame retardant at the flame retardant inlet, this method results in a decrease in the uniformity of the mixing of silicone oil and flame retardant. This leads to changes in the foam cell structure and uniformity, resulting in an increase in thermal conductivity, a decrease in compressive strength, and a slight decrease in the uniformity of thermal conductivity and compressive strength.

[0139] A comparison between graphene heat-insulating and non-combustible board 1# and graphene heat-insulating and non-combustible board 9# reveals that the foaming agent in graphene heat-insulating and non-combustible board 9# was not initially dispersed by the white material and catalyst. As a result, the uniformity of mixing of the foaming agent and the flame retardant in the high-speed mixing chamber decreased, leading to a decrease in foaming uniformity. Consequently, the various properties and uniformity of the board decreased to varying degrees.

[0140] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A production apparatus for graphene heat-insulating and non-combustible panels, characterized in that, include: A foaming agent storage tank, wherein the foaming agent storage tank is used to contain foaming agent and is connected to a foaming agent metering device; A black material storage tank, which is used to contain polyurethane black material and is connected to a black material metering device; The white material storage tank is used to contain polyurethane white material and is connected to the white material metering device. A catalyst storage tank, which is used to contain the catalyst and is connected to a catalyst metering device; A flame retardant mixing tank, wherein the flame retardant mixing tank is used for mixing flame retardants; A flame retardant feed hopper is provided, with the upper part of the flame retardant feed hopper connected to the flame retardant mixing tank via a first spiral feed pipe. A solid metering device is provided below the flame retardant feed hopper. The weight ratio of catalyst, foaming agent, black material, white material and flame retardant is (0.2-1.5):(15-20):(95-110):80:(380-440). A buffer tank, with an opening at the top and located at the discharge end of the solid metering device, and a second spiral feed pipe connected to the side wall of the buffer tank; A high-speed mixing chamber is provided, one side of which is connected to the outlet of the second spiral feed pipe, and the other side of which is provided with an injection port. A high-speed stirrer is provided in the high-speed mixing chamber, the speed of which is 1500-3000 rpm, and the temperature of the high-speed mixing chamber is 26~35℃. The injection gun is located at one end of the high-speed mixing chamber away from the second spiral feed tube. The injection gun is used to inject a premix of foaming agent, white material, black material and catalyst into the high-speed mixing chamber through the injection port. A foaming mechanism is located below the high-speed mixing chamber. The foaming mechanism includes a connecting pipe, a discharge port, and a support rod. The connecting pipe is a flexible hose and is used to connect the high-speed mixing chamber and the discharge port. The discharge port has openings at both the top and bottom. The discharge port is located on the support rod and can move along the support rod. The support rod is located above the mold of the foaming mechanism and extends from the width direction of the graphene heat-insulating and non-combustible board. A curing mechanism is used to cure the foamed graphene heat-insulating and non-combustible board; A static mixer, wherein the inlet of the static mixer is connected to a foaming agent metering device, a white component metering device, and a catalyst metering device, for mixing the foaming agent, white component, and catalyst; the outlet of the static mixer is connected to the first inlet of a dispensing gun, and the black component metering device is connected to the second inlet of the dispensing gun; A temperature control component is used to control the temperature of the high-speed mixing chamber.

2. A production process for a graphene heat-insulating and non-combustible board, characterized in that, Includes the following steps: (1) The catalyst storage tank, foaming agent storage tank, black material storage tank and white material storage tank respectively deliver the catalyst, foaming agent, black material and white material into the injection gun to obtain the premix. The foaming agent, white material and catalyst are first mixed in a static mixer and then mixed with black material in the injection gun to obtain the premix. The premix enters the high-speed mixing chamber through the injection gun from the injection port. The white material storage tank contains 0.8-1.5 wt% water and 0.3-1 wt% silicone oil. The weight ratio of catalyst, foaming agent, black material, white material and flame retardant is (0.2-1.5): (15-20): (95-110): 80: (380-440). (2) The flame retardant enters from the flame retardant mixing tank into the flame retardant feed hopper, then enters the buffer tank through the solid metering device, and then flows out of the buffer tank through the second spiral feed pipe to the high-speed mixing chamber to mix with the premixed material to obtain a mixture. The temperature of the high-speed mixing chamber is 26~35℃. The flame retardant feed hopper is also equipped with a silicone oil inlet. After the silicone oil and flame retardant are mixed evenly in the flame retardant feed hopper, they are discharged onto the solid metering device. The silicone oil accounts for 0.3wt%~1wt% of the amount of flame retardant used. The flame retardant is selected from materials with a weight ratio of 1: (0.5~0.8) ppm graphene oxide-coated inorganic flame retardant and modified expandable graphite, wherein the modified expandable graphite is obtained by modifying protocatechuic acid expandable graphite, and the modification steps of the modified expandable graphite are as follows: the expandable graphite is placed in a protocatechuic acid solution and immersed at 40~50℃ for 30 min, and then transferred to a microwave dryer for drying. The weight ratio of expandable graphite to protocatechuic acid solution is 1:(3~5), and the concentration of protocatechuic acid in the protocatechuic acid solution is 0.5~0.9 mg / ml. (3) The mixture is discharged from the outlet of the high-speed mixing chamber to the foaming mechanism for foaming to obtain a board to be cured; (4) The board to be cured is transported to the curing mechanism and cured at 40~60°C for at least 2 hours to obtain the graphene heat-insulating and non-combustible board.

3. The production process according to claim 2, characterized in that, In step (3), the foaming temperature in the foaming mechanism is 50~70℃.

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