A heat preservation box with cavity foaming heat preservation structure and a preparation method thereof

Abstract

This invention relates to the field of dry ice insulated boxes, and discloses an insulated box with an in-cavity foam insulation structure and its manufacturing method. The insulated box includes a lid shell and a body shell, both of which have an insulation layer embedded in their cavities. The insulation layer is composed of a polystyrene foam layer, a VIP vacuum board, and a polyurethane foam layer stacked sequentially. The key feature is that the polyurethane foam layer is formed by injecting foaming material into the cavity of the lid shell or body shell itself, seamlessly filling the gaps not occupied by the polystyrene foam layer and the VIP vacuum board. This invention, through in-situ injection of foaming material, effectively eliminates gaps in the insulation layer within the shell cavity and the resulting thermal bridging effect, and firmly locks the fragile VIP vacuum board, preventing shaking and wear during transportation, thereby significantly improving the overall insulation performance and service life of the insulated box.

Description

Technical Field

[0001] This invention relates to the field of dry ice insulation box technology, and in particular to an insulation box with an internal foam insulation structure and its preparation method. Background Technology

[0002] The traditional rotomolded insulated boxes used in dry ice factories today have a high evaporation rate and short lifespan, resulting in a large amount of dry ice evaporating during production and transportation. This no longer meets the national low-carbon goals, and product upgrades are urgently needed.

[0003] Dry ice insulated boxes are mainly used in dry ice production plants to store and transport dry ice. They are important storage and transportation equipment for low-temperature cold sources such as pharmaceuticals, food, and temperature-sensitive chemical products.

[0004] In existing technologies, insulated box shells are typically manufactured using rotational molding, where the cavity is primarily filled with polyurethane granules for foaming, forming a single polyurethane insulation material. Due to the limitations of single-layer polyurethane foam's insulation performance, existing insulated boxes exhibit poor overall insulation performance, making it difficult to meet the demands of high-standard cold chain transportation.

[0005] To improve insulation performance, it is essential to introduce a composite insulation layer with superior insulation properties (i.e., a high-efficiency insulation structure composed of polystyrene foam layers, VIP vacuum panels, and polyurethane foam layers) inside the insulated box shell. However, in actual manufacturing and application, directly introducing composite insulation panels faces structural defects: after the prefabricated or stacked composite insulation layer is installed in the shell cavity, gaps inevitably form between the prefabricated or stacked composite insulation layer and the inner wall of the shell, as well as between the layers. The presence of these gaps not only creates thermal bridges, preventing the full utilization of the excellent insulation performance of materials such as VIP vacuum panels, but also leaves the composite insulation layer in a non-fixed state within the cavity. This makes it prone to shaking during handling or transportation, leading to friction and wear of internal materials (especially the fragile VIP vacuum panels), severely affecting the service life and insulation reliability of the insulated box.

[0006] The drawback of existing technology is: while introducing a composite structure of polystyrene foam layer and VIP vacuum board inside the insulated box, how to effectively eliminate the gaps in the insulation layer within the box body and lid shell cavity. Summary of the Invention

[0007] This invention provides an insulated box with an insulated cavity structure and its preparation method. The technical problem to be solved is: how to effectively eliminate the gaps in the insulation layer in the box body and the box cover cavity while introducing a composite structure of polystyrene foam layer and VIP vacuum board in the insulated box.

[0008] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0009] In a first aspect, an insulated box with an insulated cavity structure includes a lid shell 10, a body shell 20, and an insulation layer 30. The insulation layer 30 is embedded in the cavities of both the lid shell 10 and the body shell 20. The insulation layer 30 is characterized in that it is composed of a polystyrene foam layer, a VIP vacuum board, and a polyurethane foam layer stacked sequentially.

[0010] The polyurethane foam shaping layer is formed by injecting foaming material into the cavity of the box cover shell 10 or the box body shell 20 and shaping it, seamlessly filling the gaps in the cavity of the box cover shell 10 and the box body shell 20 that are not occupied by the polystyrene foam layer and the VIP vacuum board.

[0011] Furthermore, in the three-layer structure of the insulation layer in the box cover shell 10 or the box body shell 20, the polystyrene foam layer is closest to the insulation cavity of the insulated box;

[0012] The surface of the polystyrene foam layer is provided with a first groove, and the VIP vacuum plate is embedded into the first groove.

[0013] Furthermore, the lid shell 10 is formed by the inner lid shell 11 and the outer lid shell 12 being fastened together by a mortise and tenon structure; the body shell 20 is formed by the inner shell 22 and the outer shell 21 being fastened together by a mortise and tenon structure.

[0014] The inner shell 11 of the box cover and the inner shell 22 of the box are two components that constitute the housing cavity of the insulated box.

[0015] Furthermore, the female and male openings are composed of a boss and a groove;

[0016] The inner shell 11 and the outer shell 12 of the box lid are respectively provided with protrusions and grooves, and the two are interlocked with each other.

[0017] The inner shell 22 and the outer shell 21 of the box are respectively provided with bosses and grooves, and the two are interlocked with each other.

[0018] Furthermore, the inner shell 11 and the outer shell 12 of the box lid are different colors, and after they are fastened together, the inner shell 11 of the box lid is exposed to the outside of the insulated box to present a warning strip.

[0019] Furthermore, a hinge assembly 40 and a latch assembly 30 are provided between the lid housing 10 and the body housing 20 to facilitate the opening / closing of the lid, and the latch assembly is used to lock or release the lid housing 10 and the body housing 20.

[0020] Nuts are pre-embedded inside the box cover shell 10 and the box body shell 20 at the installation positions of the hinge assembly 40 and the buckle assembly 30. The pre-embedded nuts are used to fix the hinge assembly and the buckle assembly respectively by bolts.

[0021] Furthermore, two handle openings 22 are provided on the outer wall of the box body, and the handle plate 50 is fixed to the inner side wall of the box body 21. The handle plate 50 and the inner side wall of the box body 21 form a hand grabbing cavity, which can accommodate part of the carrier's hand.

[0022] Furthermore, a valve seat is disposed inside the box cover, and the valve seat has an inlet for communicating with the receiving cavity of the insulated box;

[0023] Valve core 13, located inside the valve seat, blocks the valve seat inlet based on its own weight;

[0024] The pressure relief pipe 14 has an air inlet connected to the valve seat and an exhaust port 141 extending to the outside of the box cover.

[0025] Once the air pressure inside the insulation box overcomes the weight of the valve core, the gas is discharged from the insulation box through the valve seat and pressure relief pipe, thus completing the pressure relief.

[0026] Furthermore, the valve seat is divided into a lower valve body 111 and an upper valve body 121;

[0027] The lower valve body 111 is fixed to the inner shell 11 of the box cover;

[0028] The upper valve body 121 is fixed to the outer shell 12 of the box cover;

[0029] When the inner shell 11 and the outer shell 12 of the box cover are assembled and fastened, the lower valve body 111 and the upper valve body 121 are connected to form a complete valve seat.

[0030] Furthermore, the sealing surface of the valve core 13 is a convex spherical surface or a plane, and the sealing surface of the valve seat is a corresponding concave arc surface or a plane; and the sealing surface is provided with a rubber sealing layer.

[0031] Furthermore, the pressure relief pipe 14 is inclined downward at an angle of 30°-75° to the horizontal plane, and the exhaust port of the pressure relief pipe 14 is inclined downward.

[0032] Secondly, a method for preparing an insulated box with an in-cavity foam insulation structure, characterized by comprising the following steps:

[0033] Step 1: Shell preparation: The inner shell, outer shell, inner shell, and outer shell of the box are injection molded using polymer materials; during the injection molding of the inner shell and outer shell of the box, the lower valve body and upper valve body are integrally molded at the side wall simultaneously;

[0034] Step 2: Pre-installation of inner insulation components: Pre-install inner foam structural components as polystyrene foam layers on the inner surface of the inner shell of the box cover and the inner shell of the box, and open the first groove on its surface for embedding the VIP vacuum plate.

[0035] Step 3, VIP Fixing: Embed the VIP vacuum plate into the first groove, use aluminum foil tape to bind and fix the VIP vacuum plate, and cover the edge of the VIP vacuum plate for edge sealing and fixing;

[0036] Step 4: Pressure relief valve assembly: Place the valve core made of polymer material above the valve seat of the lower valve body, and form a sealing pair by its own weight;

[0037] Step 5: Pre-filling and fastening:

[0038] Before fastening the inner shell and outer shell of the lid, the polyurethane foam material is evenly placed inside the inner shell of the lid. Then, the inner shell and outer shell of the lid, and the inner shell and outer shell of the box are fastened together using the interlocking joint structure. During fastening, the upper valve body and lower valve body are aligned to form a complete valve seat and cover the valve core. Finally, the shell is permanently fixed with fasteners.

[0039] Step Six: Foaming and Setting:

[0040] A pre-set filling port is made on the outside of the snap-fit ​​box, and polyurethane foam material is injected into the box cavity through the filling port, and then the filling port is sealed; finally, the box and the lid that have been filled with polyurethane foam material are placed in the corresponding molds for foaming and shaping curing.

[0041] Furthermore, in step three, the binding fixation is performed by wrapping around the four vertical edges or the horizontal perimeter of the VIP vacuum plate.

[0042] Furthermore, in step four, the mass m of the valve core is controlled between 2g and 20g. By controlling the ratio of the valve core mass to the effective sealing area A of the valve seat, the opening pressure P satisfies the formula P=mg / A, and the value of P is in the range of 0.0005MPa-0.005MPa.

[0043] Furthermore, in step six, the injection pressure of the polyurethane foam material is 0.1-0.3 MPa, the mold temperature is 40-60℃, the curing time is 10-20 minutes, and the density of the formed polyurethane foam layer is 35-50 kg / m³.

[0044] The beneficial effects of this invention are as follows:

[0045] By pre-laying a polystyrene foam layer and a VIP vacuum panel inside the box shell cavity, followed by direct injection of polyurethane foam material for in-situ shaping and foaming, the polyurethane foam seamlessly fills all unoccupied gaps, completely eliminating the thermal bridging effect caused by traditional prefabricated insulation panel assembly. Simultaneously, it firmly locks the fragile VIP vacuum panel, preventing shaking, friction, and wear during transportation, thereby significantly improving the overall insulation performance and service life of the insulated box. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the overall structure of this application;

[0047] Figure 2 This is a schematic diagram of the overall structure of this application;

[0048] Figure 3 This is a schematic diagram of the structure of the box cover shell;

[0049] Figure 4 This is an exploded view of the enclosure.

[0050] Figure 5 This is a top view of the box cover shell;

[0051] Figure 6 for Figure 5 Sectional view of AA. Detailed Implementation

[0052] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. Identical components are indicated by the same reference numerals.

[0053] It should be noted that the terms “front,” “back,” “left,” “right,” “up,” and “down” used in the following description refer to the directions shown in the attached diagram, while the terms “inside” and “outside” refer to the directions toward or away from the geometric center of a specific component, respectively.

[0054] To make the content of this invention easier to understand, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0055] Example 1

[0056] An insulated box with an in-cavity foam insulation structure includes a lid shell 10, a body shell 20, and an insulation layer 30. The insulation layer 30 is embedded in the cavities of both the lid shell 10 and the body shell 20. The insulation layer 30 is characterized in that it is composed of a polystyrene foam layer, a VIP vacuum board, and a polyurethane foam shaping layer stacked sequentially.

[0057] The polyurethane foam shaping layer is formed by injecting foaming material into the cavity of the box cover shell 10 or the box body shell 20 and shaping it, seamlessly filling the gaps in the cavity of the box cover shell 10 and the box body shell 20 that are not occupied by the polystyrene foam layer and the VIP vacuum board.

[0058] In summary, by pre-laying polystyrene foam layers and VIP vacuum panels within the cavities of the lid shell 10 and the body shell 20, followed by direct injection of polyurethane foam material for in-situ shaping and foaming, the effect is that the polyurethane foam seamlessly fills all unoccupied gaps, completely eliminating the thermal bridging effect caused by traditional prefabricated insulation panel assembly. Simultaneously, it firmly locks the fragile VIP vacuum panels, preventing shaking, friction, and wear during transportation, thereby significantly improving the overall insulation performance and service life of the insulated box.

[0059] Furthermore, in the three-layer structure of the insulation layer in the box cover shell 10 or the box body shell 20, the polystyrene foam layer is closest to the insulation cavity of the insulated box;

[0060] The surface of the polystyrene foam layer is provided with a first groove, and the VIP vacuum plate is embedded into the first groove. This achieves precise pre-positioning of the core insulation material, the VIP vacuum plate, preventing displacement during subsequent high-pressure foaming processes or handling, and ensuring the structural integrity and consistency of the enclosure insulation layer.

[0061] Furthermore, the lid shell 10 is formed by the inner lid shell 11 and the outer lid shell 12 being fastened together by a mortise and tenon structure; the body shell 20 is formed by the inner shell 22 and the outer shell 21 being fastened together by a mortise and tenon structure.

[0062] The inner shell 11 of the box cover and the inner shell 22 of the box are two components that constitute the housing cavity of the insulated box.

[0063] Furthermore, the female and male openings are composed of a boss and a groove;

[0064] The inner shell 11 and the outer shell 12 of the box lid are respectively provided with protrusions and grooves, and the two are interlocked with each other.

[0065] The inner shell 22 and the outer shell 21 of the box are respectively provided with bosses and grooves, and the two are interlocked with each other.

[0066] Furthermore, the inner shell 11 and the outer shell 12 of the box lid are different colors, and after they are fastened together, the inner shell 11 of the box lid has a warning strip exposed to the outside of the insulated box.

[0067] By assembling the inner and outer shells of the box using different colors, a portion of the inner shell is visible on the outside of the insulated box after the lid is closed. This creates a striking visual warning strip, directly indicating the lid's closure status to operators, thus improving the standardization and safety of cold chain logistics operations.

[0068] Furthermore, a hinge assembly 40 and a latch assembly 30 are provided between the lid housing 10 and the body housing 20 to facilitate the opening / closing of the lid, and the latch assembly is used to lock or release the lid housing 10 and the body housing 20.

[0069] Nuts are pre-embedded inside the box cover shell 10 and the box body shell 20 at the installation positions of the hinge assembly 40 and the buckle assembly 30. The pre-embedded nuts are used to fix the hinge assembly and the buckle assembly respectively by bolts.

[0070] Furthermore, two handle openings 22 are provided on the outer wall of the box body, and the handle plate 50 is fixed to the inner side wall of the box body 21. The handle plate 50 and the inner side wall of the box body 21 form a hand grabbing cavity, which can accommodate part of the carrier's hand.

[0071] Furthermore, a valve seat is disposed inside the box cover, and the valve seat has an inlet for communicating with the receiving cavity of the insulated box;

[0072] Valve core 13, located inside the valve seat, blocks the valve seat inlet based on its own weight;

[0073] The pressure relief pipe 14 has an air inlet connected to the valve seat and an exhaust port 141 extending to the outside of the box cover.

[0074] Once the air pressure inside the insulation box overcomes the weight of the valve core, the gas is discharged from the insulation box through the valve seat and pressure relief pipe, thus completing the pressure relief.

[0075] In summary, the gravity-driven valve core structure allows the valve core to open and release gas through the pressure relief pipe when the slight pressure generated by the sublimation of dry ice inside the chamber overcomes its own weight. This completely eliminates traditional elastic components such as metal springs, overcoming the technical limitations of springs such as easy aging, low-temperature embrittlement, and relaxation. It achieves superior performance with zero maintenance costs, automatic pressure relief, and safe direct discharge in case of failure.

[0076] Furthermore, the valve seat is divided into a lower valve body 111 and an upper valve body 121;

[0077] The lower valve body 111 is fixed to the inner shell 11 of the box cover;

[0078] The upper valve body 121 is fixed to the outer shell 12 of the box cover;

[0079] When the inner shell 11 and the outer shell 12 of the box cover are assembled and fastened, the lower valve body 111 and the upper valve body 121 are connected to form a complete valve seat.

[0080] The valve seat is cleverly disassembled into a lower valve body and an upper valve body, which are integrally molded during the injection molding of the inner and outer casings. When the casings are snapped together, they automatically assemble into a complete valve seat. The result is that the cumbersome process of installing and securing individual valves is eliminated, creating a permanent, non-removable enclosure structure. This reduces manufacturing costs and fundamentally eliminates the risk of pressure leakage failure caused by unauthorized disassembly.

[0081] Furthermore, the sealing surface of the valve core 13 is a convex spherical surface or a plane, and the sealing surface of the valve seat is a corresponding concave arc surface or a plane; and the sealing surface is provided with a rubber sealing layer.

[0082] By precisely matching the convex spherical / flat valve core with the corresponding concave arc / flat valve seat, and configuring a sealing layer on the sealing surface, a tight seal is formed. The effect is to provide a large-area, uniform contact seal, ensuring reliable airflow blocking through gravity adhesion even under extremely low air pressure conditions, thus maintaining the low-temperature environment inside the chamber.

[0083] Furthermore, the pressure relief pipe 14 is inclined downward at an angle of 30°-75° to the horizontal plane, and the exhaust port of the pressure relief pipe 14 is inclined downward.

[0084] Example 2

[0085] A method for preparing an insulated box with an internal foam insulation structure, characterized by comprising the following steps:

[0086] Step 1: Shell preparation: The inner shell, outer shell, inner shell, and outer shell of the box are injection molded using polymer materials; during the injection molding of the inner shell and outer shell of the box, the lower valve body and upper valve body are integrally molded at the side wall simultaneously;

[0087] Step 2: Pre-installation of inner insulation components: Pre-install inner foam structural components as polystyrene foam layers on the inner surface of the inner shell of the box cover and the inner shell of the box, and open the first groove on its surface for embedding the VIP vacuum plate.

[0088] Step 3, VIP Fixing: Embed the VIP vacuum plate into the first groove, use aluminum foil tape to bind and fix the VIP vacuum plate, and cover the edge of the VIP vacuum plate for edge sealing and fixing;

[0089] Step 4: Pressure relief valve assembly: Place the valve core made of polymer material above the valve seat of the lower valve body, and form a sealing pair by its own weight;

[0090] Step 5: Pre-filling and fastening:

[0091] Before fastening the inner shell of the box cover to the outer shell of the box cover, the polyurethane foam material is evenly placed inside the inner shell of the box cover; then, the inner shell of the box cover and the outer shell of the box cover, and the inner shell of the box cover and the outer shell of the box cover are fastened together through the male and female joint structure; when fastening, the upper valve body and the lower valve body are aligned to form a complete valve seat and cover the valve core, and finally the shell is permanently fixed with fasteners.

[0092] Step Six: Foaming and Setting:

[0093] A pre-set filling port is made on the outside of the snap-fit ​​box, and polyurethane foam material is injected into the box cavity through the filling port, and then the filling port is sealed; finally, the box and the lid that have been filled with polyurethane foam material are placed in the corresponding molds for foaming and shaping curing.

[0094] Furthermore, in step three, the binding fixation is performed by wrapping around the four vertical edges or the horizontal perimeter of the VIP vacuum plate.

[0095] Furthermore, in step four, the mass m of the valve core is controlled between 2g and 20g. By controlling the ratio of the valve core mass to the effective sealing area A of the valve seat, the opening pressure P satisfies the formula P=mg / A, and the value of P is in the range of 0.0005MPa-0.005MPa.

[0096] Furthermore, in step six, the injection pressure of the polyurethane foam material is 0.1-0.3 MPa, the mold temperature is 40-60℃, the curing time is 10-20 minutes, and the density of the formed polyurethane foam layer is 35-50 kg / m³.

[0097] The polystyrene foam can be either polypropylene foam or polyurethane foam.

[0098] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An insulated box with an internal foam insulation structure, comprising a lid shell, a body shell, and an insulation layer, wherein the insulation layer is embedded within the cavities of both the lid shell and the body shell, characterized in that, The insulation layer consists of a polystyrene foam layer, a VIP vacuum board, and a polyurethane foam shaping layer stacked in sequence. The polyurethane foam shaping layer is formed by injecting foaming material into the cavity of the box cover shell or the box body shell and shaping it, seamlessly filling the gaps in the cavity of the box cover shell or the box body shell that are not occupied by the polystyrene foam layer or the VIP vacuum board.

2. The insulated box with an internal foam insulation structure according to claim 1, characterized in that, The polystyrene foam layer in the three-layer structure of the insulation layer in the box cover shell or box body shell is closest to the insulation cavity of the insulated box; The surface of the polystyrene foam layer is provided with a first groove, and the VIP vacuum plate is embedded into the first groove.

3. The insulated box with an internal foam insulation structure according to claim 2, characterized in that, The box lid shell is formed by fastening an inner box lid shell and an outer box lid shell together through a mortise and tenon joint structure; the box body shell is formed by fastening an inner box shell and an outer box body shell together through a mortise and tenon joint structure. The inner shell of the box lid and the inner shell of the box are two components that constitute the cavity of the insulated box.

4. The insulated box with an internal foam insulation structure according to claim 3, characterized in that, The male and female openings consist of a boss and a groove; The inner shell and outer shell of the lid are respectively provided with protrusions and grooves, which are interlocked with each other; The inner shell and outer shell of the box are respectively provided with protrusions and grooves, and the two are interlocked with each other.

5. The insulated box with an internal foam insulation structure according to claim 3, characterized in that, The inner and outer shells of the lid are different colors, and when they are fastened together, the inner shell of the lid has a warning strip exposed on the outside of the insulated box.

6. The insulated box with an internal foam insulation structure according to claim 1, characterized in that, A hinge assembly and a latch assembly are provided between the lid shell and the body shell to facilitate the opening / closing of the lid. The latch assembly is used to lock or release the lid shell and the body shell. Nuts are pre-embedded inside the box cover shell and the box body shell at the installation positions of the hinge assembly and the buckle assembly. The pre-embedded nuts are used to fix the hinge assembly and the buckle assembly respectively by bolts.

7. The insulated box with an internal foam insulation structure according to claim 3, characterized in that, The outer shell of the box has two handle openings on its outer wall. The handle plate is fixed to the inner wall of the outer shell of the box, and the handle plate and the inner wall of the outer shell of the box form a hand grabbing cavity, which can accommodate part of the operator's hand.

8. The insulated box with an internal foam insulation structure according to claim 3, characterized in that, A valve seat is disposed inside the box cover, and the valve seat has an inlet for communicating with the receiving cavity of the insulated box; The valve core, located inside the valve seat, blocks the valve seat inlet based on its own weight; The pressure relief pipe has an air inlet connected to the valve seat and an exhaust outlet extending to the outside of the box cover. Once the air pressure inside the insulation box overcomes the weight of the valve core, the gas is discharged from the insulation box through the valve seat and pressure relief pipe, thus completing the pressure relief.

9. A thermal insulation box with an internal foam insulation structure according to claim 8, characterized in that, The valve seat is divided into a lower valve body and an upper valve body; The lower valve body is fixed to the inner shell of the box cover; The upper valve body is fixed to the outer shell of the box cover; After the inner shell and outer shell of the box cover are assembled and fastened together, the lower valve body and the upper valve body are connected to form a complete valve seat.

10. An insulated box with an internal foam insulation structure according to claim 9, characterized in that, The sealing surface of the valve core is a convex spherical surface or a flat surface, and the sealing surface of the valve seat is a corresponding concave arc surface or a flat surface; and the sealing surface is provided with a rubber sealing layer.

11. A thermal insulation box with an internal foam insulation structure according to claim 10, characterized in that, The pressure relief pipe 14 is inclined downward at an angle of 30°-75° to the horizontal plane, and the exhaust port of the pressure relief pipe is inclined downward.

12. A method for preparing an insulated box with an in-cavity foam insulation structure as described in any one of claims 1 to 3 or 8 to 11, characterized in that, Includes the following steps: Step 1: Shell preparation: The inner shell, outer shell, inner shell, and outer shell of the box are injection molded using polymer materials; during the injection molding of the inner shell and outer shell of the box, the lower valve body and upper valve body are integrally molded at the side wall simultaneously; Step 2: Pre-installation of inner insulation components: Pre-install inner foam structural components as polystyrene foam layers on the inner surface of the inner shell of the box cover and the inner shell of the box, and open the first groove on its surface for embedding the VIP vacuum plate. Step 3, VIP Fixing: Embed the VIP vacuum plate into the first groove, use aluminum foil tape to bind and fix the VIP vacuum plate, and cover the edge of the VIP vacuum plate for edge sealing and fixing; Step 4: Pressure relief valve assembly: Place the valve core made of polymer material above the valve seat of the lower valve body, and form a sealing pair by its own weight; Step 5: Pre-filling and fastening: Before fastening the inner shell and outer shell of the lid, the polyurethane foam material is evenly placed inside the inner shell of the lid. Then, the inner shell and outer shell of the lid, and the inner shell and outer shell of the box are fastened together using the interlocking joint structure. During fastening, the upper valve body and lower valve body are aligned to form a complete valve seat and cover the valve core. Finally, the shell is permanently fixed with fasteners. Step Six: Foaming and Setting: A pre-set filling port is made on the outside of the snap-fit ​​box, and polyurethane foam material is injected into the box cavity through the filling port, and then the filling port is sealed; finally, the box and the lid that have been filled with polyurethane foam material are placed in the corresponding molds for foaming and shaping curing.

13. The preparation method according to claim 12, characterized in that: In step three, the binding fixation is performed by wrapping around the four vertical edges or the horizontal perimeter of the VIP vacuum plate.

14. The preparation method according to claim 12, characterized in that: In step four, the mass m of the valve core is controlled between 2g and 20g. By controlling the ratio of the valve core mass to the effective sealing area A of the valve seat, the opening pressure P satisfies the formula P=mg / A, and the value of P is in the range of 0.0005MPa-0.005MPa.

15. The preparation method according to claim 12, characterized in that: In step six, the injection pressure of the polyurethane foam material is 0.1-0.3 MPa, the mold temperature is 40-60℃, the curing time is 10-20 minutes, and the density of the formed polyurethane foam layer is 35-50 kg / m³.

Images