Thick rubber foam material with uniform foam holes and preparation method of thick rubber foam material

Abstract

The invention relates to the field of foam materials, in particular to a thick rubber foam material with uniform foam holes and a preparation method of the thick rubber foam material. The uniform-cell thick rubber foam material comprises the following substances in parts by weight: 100 parts of rubber; 0-75 parts of a reinforcing agent; 0.5-3 parts of a vulcanizing agent; 1-200 parts of a heat conducting agent; the heat conduction agent is a metal oxide. Through the synergistic effect of multiple components, a rubber matrix with heat-conducting property and mechanical property is constructed, so that a basic guarantee is provided for the uniformity of foam holes. Specifically, through introduction of the heat conduction agent, cell uniformity is achieved, transmission of heat in the thick product can be accelerated through the high heat conduction characteristic of the metal oxide, the temperature difference between the inner layer and the outer layer is reduced, and the situation that the decomposition rate of a foaming agent is uneven due to local temperature difference is avoided, so that the gradient difference of cell sizes is reduced; according to the component design, a foundation is laid for the cell uniformity of the thick rubber foam through multi-dimensional synergy of matrix bearing, reinforcing and toughening, vulcanization shaping, heat conduction and temperature equalization.

Description

Technical Field

[0001] The invention relates to the field of foam materials, and in particular to a thick rubber foam material with uniform pores and a preparation method thereof. Background Art

[0002] With the development of industries such as construction, automobiles, packaging, electronics, and the low-altitude economy, the demand for foam materials continues to grow. Traditional methods for preparing silicone rubber foam are mainly chemical foaming and physical foaming. The chemical foaming method uses chemical foaming agents to decompose during heating to produce gas to form bubbles. During this process, it is necessary to precisely adjust the dosage of each formula and adjust the process to match the foaming agent and vulcanization speed to obtain rubber foam products that meet the requirements. Compared with the chemical foaming method, the supercritical foaming method introduces supercritical gas into the rubber matrix, which expands to form bubbles by increasing the temperature or releasing the pressure. This can form finer and more uniform bubbles with a higher closed-cell rate, making the material have better mechanical properties.

[0003] In response to the above-mentioned prior art, the inventors discovered that when using existing supercritical foaming silicone rubber materials, it is usually necessary to pre-vulcanize the silicone rubber material to increase its crosslinking density so that the matrix has the ability to support the pores, and then perform supercritical foaming, and allow the system to be vulcanized through a secondary vulcanization process to completely stabilize the pores. When thick (>10mm) rubber foam is prepared by this method, the thermal conductivity is poor because the silicone rubber matrix does not have the uniform and dense ordered crystals or charge carriers required for heat transfer. During the secondary vulcanization process at a higher temperature, the foam experiences gas escape while the crosslinker decomposes under the action of heat to produce crosslinks. The temperature difference between the inside and outside of the system leads to a significant difference in the speed of the internal and external gas exchange and crosslinking process, resulting in a serious difference in the size of the internal and external pores in the final product, and even severe surface skinning. Summary of the Invention

[0004] Based on the technical problems existing in the above-mentioned prior art, the present invention provides a thick rubber foam material with uniform pores and a preparation method thereof.

[0005] In the first aspect, the present application provides a thick rubber foam material with uniform pores, which adopts the following technical solutions: A thick rubber foam material with uniform pores comprises the following substances in parts by weight: 100 parts of rubber; Reinforcing agent 0-75 parts; 0.5-3 parts of vulcanizing agent; 1-200 parts of thermal conductor; the thermal conductor is a metal oxide.

[0006] Through the above technical solution, this application constructs a rubber matrix with both thermal conductivity and mechanical properties through the synergistic effect of multiple components, thereby providing a basic guarantee for cell uniformity. Specifically, this application achieves cell uniformity through the introduction of a thermal conductor. The high thermal conductivity of metal oxides can accelerate the transfer of heat inside thick products, reduce the temperature difference between the inner and outer layers, avoid the uneven decomposition rate of the foaming agent caused by local temperature differences, and thus reduce the gradient difference in cell size. This component design lays the foundation for the cell uniformity of thick rubber foam through the multi-dimensional synergy of "matrix load-bearing - reinforcement and toughening - vulcanization and shaping - thermal conductivity and uniform temperature".

[0007] Furthermore, the metal oxide includes micron-sized high thermal conductivity particles and nano-sized thermal conductive particles.

[0008] Through the above-mentioned technical solution, this application utilizes a composite thermal conductive material composed of micron- and nano-sized metal oxides. The micron-sized metal oxide (with larger particle size) serves as the "skeleton" of the thermal conductive network, forming long-range heat conduction channels within the rubber matrix through its high thermal conductivity. The nano-sized metal oxide (with smaller particle size) fills the gaps between the micron particles, acting as a "bridging" medium to connect weak areas between the micron particles, eliminating thermal resistance caused by the large spacing between the micron particles, and thus constructing a continuous, dense thermal conductive network. This "micron-skeleton + nano-filler" composite structure not only improves the filling efficiency of the thermal conductive material but also reduces the interfacial thermal resistance between the particles and the rubber matrix through the small size effect of the nanoparticles, further optimizing the overall thermal conductivity. The synergistic effect of the micro-nano composite thermal conductive material significantly improves the uniformity of thermal conductivity in thick rubber foam. The micron-sized particles act as a skeleton to ensure efficient heat conduction through the thickness of the thick product, reducing temperature differences between the inner and outer layers. Furthermore, the nano-sized particles fill the gaps between the thermal conductive network, eliminating "breakpoints" in the thermal conductive network, ensuring more uniform heat distribution within the matrix and avoiding localized high or low temperatures. This dual optimization directly affects the foaming process: when the material is heated, the heat is quickly transferred to the interior through the composite heat-conducting network, causing the foaming agents in the inner and outer layers to decompose synchronously. The generated gas expands evenly in the matrix, eventually forming a uniformly sized bubble structure.

[0009] Furthermore, the micron-sized high thermal conductivity particles include at least one of aluminum oxide, magnesium oxide or zinc oxide with a particle size of 10-30 μm.

[0010] Through the above technical solution, the present application selects the above-mentioned metal oxides and micron particles with a particle size range, which can not only construct an effective thermal conductive skeleton through high intrinsic thermal conductivity, but also ensure its dispersibility in the rubber matrix through appropriate particle size. During the mixing process, the aluminum oxide particles can be evenly distributed in the rubber through mechanical shear force, forming a long-range thermal conduction channel; the high thermal conductivity of magnesium oxide further enhances the thermal conductivity of this channel; and the addition of zinc oxide can enhance the interfacial bonding force between the particles and the matrix and reduce the interfacial thermal resistance through the interaction between its polar surface and the rubber molecular chain. This design not only ensures the thermal conductivity efficiency of the thermal conductor, but also takes into account the processing performance and mechanical properties of the material, providing a stable skeleton foundation for the subsequent filling and synergistic effect of nanoparticles.

[0011] Furthermore, the nano-scale thermally conductive particles include at least one of nano-aluminum oxide or nano-magnesium oxide with a particle size of 50-200 nm.

[0012] Through the above technical solution, the application selects the addition of nano-scale metal oxides to significantly optimize the continuity and uniformity of the thermal conductive network. Nano-alumina is filled in the gaps between the micron alumina particles, and the gaps originally occupied by the rubber matrix can be replaced by highly thermally conductive nano-particles, so that the heat flow can be more efficiently transmitted through the "micron-nano" path; the high thermal conductivity of nano-magnesium oxide further enhances this transfer efficiency. This filling effect not only improves the overall thermal conductivity of the thick product, but also makes the temperature field of the inner and outer layers more uniform during the foaming process through the temperature equalization effect, synchronizes the decomposition rate of the foaming agent, and ultimately forms bubbles of uniform size. In addition, the small size of the nanoparticles makes it easier to disperse during the mixing process, avoiding local thermal conductivity defects caused by the agglomeration of large particles, and further ensuring the uniformity of the thermal conductive network.

[0013] Furthermore, the reinforcing agent includes a mixture of one or more of precipitated silica and fumed silica.

[0014] Furthermore, the vulcanizing agent includes any one or more of DCP, DTBP, BPO, BIPB, TBPB, BP, DCBP, bis-24, and bis-25.

[0015] Furthermore, the functional material includes one or more of a flame retardant, an anti-aging agent, and an antistatic agent.

[0016] In a second aspect, the present application provides a method for preparing a thick rubber foam material with uniform pores, using the following technical solution: A method for preparing a thick rubber foam material with uniform pores, comprising the following steps: S1. Thermal Conductive Agent Pretreatment: Stir and mix the thermal conductive agent and silane coupling agent, disperse them ultrasonically, and vacuum dry them to complete the thermal conductive agent pretreatment; S2, step mixing: adding rubber and thermal conductive agent into a mixing device, mixing for 10-15 minutes, then adding reinforcing agent, continuing mixing, then adding hydroxy silicone oil, mixing for 5-8 minutes, to obtain a rubber mixture; S3, pre-vulcanization treatment: After the mixed rubber and the vulcanizing agent are mixed, the roller distance is adjusted to produce a sheet after uniformity, and the sheet is hung to cool and placed after cutting to obtain a film, and the film is placed in a mold and pre-vulcanized to obtain a sheet to be foamed; S4, supercritical foaming: placing the sheet to be foamed in a supercritical foaming device, using supercritical carbon dioxide or nitrogen as a medium, foaming at 65-75°C and 14-16 MPa for 2.5-3.5 hours to obtain a foamed sheet; S5. Segmented vulcanization and shaping: The foamed sheet is vulcanized in segments to prepare a thick rubber foam material with uniform pores.

[0017] Through the above technical solution, this application optimizes the process parameters and solves key problems such as "uneven dispersion of thermal conductor", "unstable cell growth" and "insufficient structural finalization". First, through pretreatment and step-by-step mixing, the uniform distribution of the thermal conductor in the matrix is ensured, providing a basis for temperature uniformity; then, through preliminary cross-linking during pre-vulcanization, the matrix has sufficient strength to support cell expansion during foaming; the mild conditions of supercritical foaming avoid local overheating caused by high temperature, and with the temperature uniformity of the thermal conductor, the cell nuclei are evenly generated; the segmented vulcanization ensures the stability of the cells at different stages through progressive cross-linking from "low temperature to medium temperature to high temperature", and finally obtains a thick rubber foam material with uniform cells and stable performance.

[0018] Furthermore, the pre-vulcanization treatment is as follows: applying a 10T uniform magnetic field in a vulcanization device, pre-vulcanizing at 125-145°C and 12-14MPa for 6-30min to complete the pre-vulcanization treatment.

[0019] Through the above technical solution, this application defines the specific conditions for the pre-vulcanization treatment, namely, applying a uniform magnetic field of 10T. Although micron-sized metal oxides are not ferromagnetic materials, the anisotropy of their particles will induce directional alignment in a strong magnetic field due to the induction of magnetic moments. By setting the direction of the magnetic field to be consistent with the thickness direction of the film, the micron-sized metal oxides can be induced to align along the thickness direction, forming a "vertical heat conduction channel" and significantly improving the thermal conductivity efficiency of thick products in the thickness direction (the vertical thermal conductivity coefficient is higher than the horizontal direction). This directional arrangement reduces the resistance to heat transfer in the thickness direction, making the temperature of the inner and outer layers more uniform, synchronizing the decomposition rate of the foaming agent, further improving the temperature uniformity effect, and providing a stronger guarantee for the uniformity of the foam cells.

[0020] Furthermore, the segmented vulcanization and shaping process comprises the following steps: The foamed sheet is sequentially vulcanized at 150-180° C. for 10-60 min, 170-190° C. for 30-120 min, and 190-210° C. for 60-240 min to prepare a thick rubber foam material with uniform pores.

[0021] Through the above technical solution, this application perfectly matches the growth law of "expansion-adjustment-fixation" of the foam cells through the progressive control of "elastic buffering-plastic stability-rigid shaping" during segmented vulcanization. For thick rubber foam, this process design is particularly important: if "one-time high-temperature vulcanization" is adopted, the outer layer will quickly cross-link due to being exposed to high temperature first, while the inner layer will not be cross-linked enough due to the lag in heat transfer. Ultimately, the outer layer foam cells are restricted in growth, and the inner layer foam cells over-expand due to the overly soft matrix, forming a significant gradient difference. The gradient temperature setting of segmented vulcanization, combined with the temperature-uniform effect of the thermal conductor, synchronizes the vulcanization process of the inner and outer layers, and the foam cells grow uniformly and stably shape in each stage, ultimately achieving the uniform structural goal of "small difference in the diameter of the inner and outer layer foam cells".

[0022] In summary, this application has the following beneficial effects: First, this application uses the synergistic effect of multiple components to construct a rubber matrix with both thermal conductivity and mechanical properties, thereby providing a basic guarantee for cell uniformity. Specifically, this application achieves cell uniformity through the introduction of a thermal conductor. The high thermal conductivity of metal oxides can accelerate the transfer of heat within thick products, narrow the temperature difference between the inner and outer layers, and avoid uneven decomposition rates of the foaming agent caused by local temperature differences, thereby reducing the gradient difference in cell size. This component design lays the foundation for cell uniformity in thick rubber foam through the multi-dimensional synergy of "matrix load-bearing - reinforcement and toughening - vulcanization and shaping - thermal conductivity and temperature uniformity."

[0023] Second, this application uses a composite of micron-scale and nano-scale metal oxides to form a thermal conductive material. Micron-scale metal oxides serve as the "skeleton" of the thermal conductive network, forming long-range thermal conductive channels in the rubber matrix through their own high thermal conductivity; nano-scale metal oxides are filled in the gaps between micron particles, acting as a "bridging" medium to connect the weak areas between micron particles, eliminating the thermal resistance caused by the large spacing between micron particles, thereby constructing a continuous and dense thermal conductive network. This "micron skeleton + nano-filling" composite structure not only improves the filling efficiency of the thermal conductor, but also reduces the interfacial thermal resistance between the particles and the rubber matrix through the small size effect of the nanoparticles, further optimizing the overall thermal conductivity.

[0024] Third, this application defines the specific conditions for the pre-vulcanization treatment, namely, applying a uniform magnetic field of 10 T. Although micron-sized metal oxides are not ferromagnetic materials, the anisotropy of their particles will induce directional alignment in a uniform magnetic field due to the induction of magnetic moments. By setting the direction of the magnetic field to coincide with the thickness of the film, the micron-sized metal oxides can be induced to align along the thickness direction, forming a "vertical heat conduction channel" and significantly improving the thermal conductivity of thick products in the thickness direction (the vertical thermal conductivity is higher than the horizontal direction). This directional arrangement reduces the resistance to heat transfer in the thickness direction, making the temperature of the inner and outer layers more uniform, synchronizing the decomposition rate of the foaming agent, further improving the temperature uniformity, and providing a stronger guarantee for bubble uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a cross-sectional view of the cells of the thick rubber foam material with uniform cells prepared in Example 2 of the present application; Figure 2 This is a cross-sectional view of the cells of the thick rubber foam material with uniform cells prepared in Example 9 of the present application; Figure 3 This is a cross-sectional view of the cells of the foam material prepared in Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0026] The present application is further described in detail below with reference to the embodiments.

[0027] Preparation Example 1 Thermal Conductive Agent 1 200 g of aluminum oxide with a particle size of 10 μm and 100 g of nano-aluminum oxide with a particle size of 50 nm were mixed and stirred, and then the mixture was collected to obtain a thermal conductor 1.

[0028] Preparation Example 2 Thermal Conductive Agent 2 300 g of magnesium oxide with a particle size of 20 μm and 100 g of nano magnesium oxide with a particle size of 120 nm were mixed and stirred, and then the mixture was collected to obtain a thermal conductor 2.

[0029] Preparation Example 3 Thermal Conductive Agent 3 400 g of zinc oxide with a particle size of 30 μm and 100 g of nano magnesium oxide with a particle size of 200 nm were mixed and stirred, and then collected to obtain thermal conductor 3.

[0030] Example 1 A thick rubber foam material with uniform pores comprises the following substances: 100 kg of rubber VMQ, 20 kg of reinforcing agent precipitated silica, 1 kg of vulcanizing agent DCP, and 10 kg of thermal conductor 1.

[0031] A method for preparing a thick rubber foam material with uniform pores, comprising the following steps: S1. Thermal Conductive Agent Pretreatment: Thermal Conductive Agent 1 and 5% Silane Coupling Agent Ethanol Solution were mixed in a mass ratio of 1:1 and ultrasonically dispersed at 300W for 30 minutes. The mixture was then vacuum dried to complete the thermal conductive agent pretreatment. S2, step-by-step mixing: rubber and thermal conductor 1 are added to an internal mixer, mixed for 10 minutes, and then a reinforcing agent, precipitated silica, is added. After further mixing, hydroxy silicone oil is added and mixed for 5 minutes to obtain a rubber mixture; S3, pre-vulcanization treatment: the rubber mix and the vulcanizing agent are placed on an open rubber mixer for mixing, the roller distance is adjusted after uniformity, the film is cut and hung to cool and placed for 12 hours to obtain a film with a thickness of 7 mm, the film is placed in a mold, a 10T uniform magnetic field is applied to the vulcanization device, and pre-vulcanization is carried out at 135 ° C and 12 MPa for 14 minutes to complete the pre-vulcanization treatment to obtain a sheet to be foamed; S4, supercritical foaming: placing the sheet to be foamed in a supercritical foaming device, using supercritical carbon dioxide or nitrogen as the medium, and foaming at 65°C and 14 MPa for 2.5 hours to obtain a foamed sheet; S5. Segmented vulcanization and shaping: The foam sheet is vulcanized in segments, with the first segment vulcanization temperature controlled at 150°C for 10 minutes; the second segment vulcanization temperature controlled at 170°C for 30 minutes; and the third segment vulcanization temperature controlled at 190°C for 60 minutes, thereby obtaining a thick rubber foam material with uniform pores.

[0032] Example 2 A thick rubber foam material with uniform pores comprises the following substances: 100 kg of rubber VMQ, 30 kg of reinforcing agent precipitated silica, 1 kg of vulcanizing agent DCP, and 100 kg of thermal conductor 1.

[0033] A method for preparing a thick rubber foam material with uniform pores, comprising the following steps: S1. Thermal Conductive Agent Pretreatment: Thermal Conductive Agent 2 and 5% Silane Coupling Agent Ethanol Solution were mixed in a mass ratio of 1:1 and ultrasonically dispersed at 300W for 30 minutes. The mixture was then vacuum dried to complete the thermal conductive agent pretreatment. S2, step-by-step mixing: rubber and thermal conductor 1 are added to an internal mixer, mixed for 12 minutes, and then a reinforcing agent, precipitated silica, is added. After further mixing, hydroxy silicone oil is added and mixed for 6 minutes to obtain a rubber mixture; S3, pre-vulcanization treatment: the rubber mix and the vulcanizing agent are placed on an open rubber mixer for mixing, the roller distance is adjusted to be uniform, the sheet is cut and hung to cool and placed for 24 hours to obtain a film with a thickness of 7 mm, the film is placed in a mold, a 10T uniform magnetic field is applied to the vulcanization device, and pre-vulcanization is carried out at 130 ° C and 13 MPa for 25 minutes to complete the pre-vulcanization treatment to obtain a sheet to be foamed; S4, supercritical foaming: placing the sheet to be foamed in a supercritical foaming device, using supercritical carbon dioxide or nitrogen as a medium, and foaming at 70°C and 15 MPa for 3 hours to obtain a foamed sheet; S5. Segmented vulcanization and shaping: The foam sheet is vulcanized in segments, with the first segment vulcanization temperature controlled at 165°C for 30 minutes; the second segment vulcanization temperature controlled at 180°C for 75 minutes; and the third segment vulcanization temperature controlled at 200°C for 150 minutes, thereby obtaining a thick rubber foam material with uniform pores.

[0034] Example 3 A thick rubber foam material with uniform pores comprises the following substances: 100 kg of rubber VMQ, 75 kg of reinforcing agent precipitated silica, 1 kg of vulcanizing agent DCP, and 200 kg of thermal conductor 1.

[0035] A method for preparing a thick rubber foam material with uniform pores, comprising the following steps: S1. Thermal Conductive Agent Pretreatment: Thermal Conductive Agent 1 and 5% Silane Coupling Agent Ethanol Solution were mixed in a mass ratio of 1:1 and ultrasonically dispersed at 300W for 30 minutes. The mixture was then vacuum dried to complete the thermal conductive agent pretreatment. S2, step-by-step mixing: rubber and thermal conductor 1 are added to an internal mixer, mixed for 15 minutes, and then a reinforcing agent, precipitated silica, is added. After further mixing, hydroxy silicone oil is added and mixed for 8 minutes to obtain a rubber mixture; S3, pre-vulcanization treatment: the rubber mix and the vulcanizing agent are placed on an open rubber mixer for mixing, the roller distance is adjusted after uniformity, the film is hung for cooling and placed for 36 hours after cutting to obtain a film with a thickness of 7 mm, the film is placed in a mold, a 10T uniform magnetic field is applied to the vulcanization device, and pre-vulcanization is carried out at 135 ° C and 14 MPa for 14 minutes to complete the pre-vulcanization treatment to obtain a sheet to be foamed; S4, supercritical foaming: placing the sheet to be foamed in a supercritical foaming device, using supercritical carbon dioxide or nitrogen as the medium, and foaming at 75°C and 16 MPa for 3.5 hours to obtain a foamed sheet; S5. Segmented vulcanization and shaping: The foam sheet is vulcanized in segments, with the first segment vulcanization temperature controlled at 180°C and the time at 60 min; the second segment vulcanization temperature controlled at 190°C and the time at 120 min; the third segment vulcanization temperature controlled at 210°C and the time at 240 min, thereby obtaining a thick rubber foam material with uniform pores.

[0036] Example 4 A thick rubber foam material with uniform pores, comprising the following substances: 100kg of rubber VMQ, 30kg of reinforcing agent precipitated silica, 1kg of vulcanizing agent DCP, and 100kg of thermal conductor 2.

[0037] A method for preparing a thick rubber foam material with uniform pores, comprising the following steps: S1. Thermal Conductive Agent Pretreatment: Thermal Conductive Agent 2 and 5% Silane Coupling Agent Ethanol Solution were mixed in a mass ratio of 1:1 and ultrasonically dispersed at 300W for 30 minutes. The mixture was then vacuum dried to complete the thermal conductive agent pretreatment. S2, step-by-step mixing: rubber and thermal conductor 1 are added to an internal mixer, mixed for 12 minutes, and then a reinforcing agent, precipitated silica, is added. After further mixing, hydroxy silicone oil is added and mixed for 6 minutes to obtain a rubber mixture; S3, pre-vulcanization treatment: the rubber mix and the vulcanizing agent are placed on an open rubber mixer for mixing, the roller distance is adjusted to be uniform, the sheet is cut and hung to cool and placed for 24 hours to obtain a film with a thickness of 7 mm, the film is placed in a mold, a 10T uniform magnetic field is applied to the vulcanization device, and pre-vulcanization is carried out at 130 ° C and 13 MPa for 25 minutes to complete the pre-vulcanization treatment to obtain a sheet to be foamed; S4, supercritical foaming: placing the sheet to be foamed in a supercritical foaming device, using supercritical carbon dioxide or nitrogen as a medium, and foaming at 70°C and 15 MPa for 3 hours to obtain a foamed sheet; S5. Segmented vulcanization and shaping: The foam sheet is vulcanized in segments, with the first segment vulcanization temperature controlled at 165°C for 30 minutes; the second segment vulcanization temperature controlled at 180°C for 75 minutes; and the third segment vulcanization temperature controlled at 200°C for 150 minutes, thereby obtaining a thick rubber foam material with uniform pores.

[0038] Example 5 A thick rubber foam material with uniform pores, comprising the following substances: 100 kg of rubber VMQ, 30 kg of reinforcing agent precipitated silica, 1 kg of vulcanizing agent DCP, and 100 kg of thermal conductor 3.

[0039] A method for preparing a thick rubber foam material with uniform pores, comprising the following steps: S1. Thermal Conductive Agent Pretreatment: Thermal Conductive Agent 3 and 5% Silane Coupling Agent Ethanol Solution were mixed in a mass ratio of 1:1 and ultrasonically dispersed at 300W for 30 minutes. The mixture was then vacuum dried to complete the thermal conductive agent pretreatment. S2, step-by-step mixing: rubber and thermal conductor 1 are added to an internal mixer, mixed for 12 minutes, and then a reinforcing agent, precipitated silica, is added. After further mixing, hydroxy silicone oil is added and mixed for 6 minutes to obtain a rubber mixture; S3, pre-vulcanization treatment: the rubber mix and the vulcanizing agent are placed on an open rubber mixer for mixing, the roller distance is adjusted to be uniform, the sheet is cut and hung to cool and placed for 24 hours to obtain a film with a thickness of 7 mm, the film is placed in a mold, a 10T uniform magnetic field is applied to the vulcanization device, and pre-vulcanization is carried out at 130 ° C and 13 MPa for 25 minutes to complete the pre-vulcanization treatment to obtain a sheet to be foamed; S4, supercritical foaming: placing the sheet to be foamed in a supercritical foaming device, using supercritical carbon dioxide or nitrogen as a medium, and foaming at 70°C and 15 MPa for 3 hours to obtain a foamed sheet; S5. Segmented vulcanization and shaping: The foam sheet is vulcanized in segments, with the first segment vulcanization temperature controlled at 165°C for 30 minutes; the second segment vulcanization temperature controlled at 180°C for 75 minutes; and the third segment vulcanization temperature controlled at 200°C for 150 minutes, thereby obtaining a thick rubber foam material with uniform pores.

[0040] Example 6 A thick rubber foam material with uniform pores, comprising the following substances: 100 kg of rubber VMQ, 1 kg of vulcanizing agent DCP, and 100 kg of thermal conductor 2.

[0041] A method for preparing a thick rubber foam material with uniform pores, comprising the following steps: S1. Thermal Conductive Agent Pretreatment: Thermal Conductive Agent 2 and 5% Silane Coupling Agent Ethanol Solution were mixed in a mass ratio of 1:1 and ultrasonically dispersed at 300W for 30 minutes. The mixture was then vacuum dried to complete the thermal conductive agent pretreatment. S2, step-by-step mixing: rubber and thermal conductor 1 are added to an internal mixer, mixed for 12 minutes, and then a reinforcing agent, precipitated silica, is added. After further mixing, hydroxy silicone oil is added and mixed for 6 minutes to obtain a rubber mixture; S3, pre-vulcanization treatment: the rubber mix and the vulcanizing agent are placed on an open rubber mixer for mixing, the roller distance is adjusted to be uniform, the sheet is cut and hung to cool and placed for 24 hours to obtain a film with a thickness of 7 mm, the film is placed in a mold, a 10T uniform magnetic field is applied to the vulcanization device, and pre-vulcanization is carried out at 130 ° C and 13 MPa for 25 minutes to complete the pre-vulcanization treatment to obtain a sheet to be foamed; S4, supercritical foaming: placing the sheet to be foamed in a supercritical foaming device, using supercritical carbon dioxide or nitrogen as a medium, and foaming at 70°C and 15 MPa for 3 hours to obtain a foamed sheet; S5. Segmented vulcanization and shaping: The foam sheet is vulcanized in segments, with the first segment vulcanization temperature controlled at 165°C for 30 minutes; the second segment vulcanization temperature controlled at 180°C for 75 minutes; and the third segment vulcanization temperature controlled at 200°C for 150 minutes, thereby obtaining a thick rubber foam material with uniform pores.

[0042] Example 7 Compared with Example 1, in Example 7, the thermal conductor 1 is replaced by aluminum oxide with an equal mass and a particle size of 10 μm.

[0043] Example 8 Compared with Example 1, in Example 8, nano-alumina with an equal mass and a particle size of 50 nm is used to replace the thermal conductor 1.

[0044] Comparative Example 1 Compared with Example 1, no thermal conductive agent 1 was added in Comparative Example 1, and the remaining steps and preparation scheme were the same as those in Example 1.

[0045] Comparative Example 2 Compared with Example 1, in Comparative Example 2, an equal mass of graphene was added instead of thermal conductor 1, and the remaining steps and preparation scheme were the same as those in Example 1.

[0046] It should be noted that the curing agents used in this application include but are not limited to DCP, DTBP, BPO, BIPB, TBPB, BP, DCBP, bis-24, bis-25; The rubber used in this application includes but is not limited to heat-vulcanized silicone rubber, fluororubber, and fluorosilicone rubber.

[0047] Performance testing Vertical thermal conductivity: Testing standard: GB / T 10294-2008 "Insulating materials - Determination of steady-state thermal resistance and related properties - Guarded hot plate method" (applicable to low thermal conductivity materials).

[0048] Tensile strength: GB / T 528-2009 “Rubber, vulcanized or thermoplastic — Determination of tensile stress-strain properties”.

[0049] The results are shown in Table 1 below: Table 1 Performance test table

[0050] From the above examples 1-8 and comparative examples 1-2 combined with Table 1 and Figure 1-3 Comparing the test results, we can find that: The vertical thermal conductivity coefficients of Examples 1-5 of the present application are significantly higher than those of Examples 7, 8, and Comparative Example 1, verifying the effectiveness of the "micron-nano synergistic thermal conductive network". It is explained that the technical solution of the present application uses a composite of micron-scale and nano-scale metal oxides to form a thermal conductive material. Micron-scale metal oxides serve as the "skeleton" of the thermal conductive network, forming long-range thermal conductive channels in the rubber matrix through their own high thermal conductivity; nano-scale metal oxides are filled in the gaps between micron particles, acting as a "bridging" medium to connect the weak areas between micron particles, eliminating the thermal resistance caused by the large spacing between micron particles, thereby constructing a continuous and dense thermal conductive network. This "micron skeleton + nano-filling" composite structure not only improves the filling efficiency of the thermal conductor, but also reduces the interfacial thermal resistance between the particles and the rubber matrix through the small size effect of the nanoparticles, further optimizing the overall thermal conductivity.

[0051] The tensile strength of Example 6 is significantly lower than that of Example 2, indicating that silica plays a key supporting role in cell stability by enhancing the mechanical properties of the matrix.

[0052] Although Comparative Example 2 has the highest thermal conductivity, its mechanical properties are significantly lower than those of the composite metal oxide system due to the poor interfacial compatibility between graphene and rubber.

[0053] The present invention has been described in detail above with reference to specific embodiments and exemplary examples. However, these descriptions should not be construed as limiting the present invention. Those skilled in the art will appreciate that various equivalent substitutions, modifications, or improvements may be made to the technical solutions and implementations of the present invention without departing from the spirit and scope of the present invention, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be determined by the appended claims.

[0054] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings conventionally understood by those skilled in the art. In the event of conflict, the definitions in this specification shall prevail.

[0055] When this specification uses the prefix "well known to those skilled in the art", "prior art" or similar terms to introduce materials, substances, methods, steps, devices or components, the objects introduced by the prefix include those commonly used in the art when this application is filed, but also include those that are not commonly used at present but will become generally recognized in the art to be suitable for similar purposes.

[0056] In the context of this specification, any matters or items not mentioned are directly applicable to those known in the art without any changes except those explicitly stated.

Claims

1. A thick rubber foam material with uniform pores, characterized in that: The composition includes the following materials in parts by weight: 100 parts of rubber; Reinforcing agent 0-75 parts; 0.5-3 parts of vulcanizing agent; 1-200 parts of thermal conductor; the thermal conductor is a metal oxide.

2. A thick rubber foam material with uniform pores according to claim 1, characterized in that: The metal oxide includes micron-sized high thermal conductivity particles and nano-sized thermal conductivity particles.

3. A thick rubber foam material with uniform pores according to claim 2, characterized in that: The micron-sized high thermal conductivity particles include at least one of aluminum oxide, magnesium oxide or zinc oxide with a particle size of 10-30 μm.

4. The thick rubber foam material with uniform pores according to claim 2, characterized in that: The nano-scale thermally conductive particles include at least one of nano-aluminum oxide or nano-magnesium oxide with a particle size of 50-200 nm.

5. The thick rubber foam material with uniform pores according to claim 1, characterized in that: The reinforcing agent includes a mixture of one or more of precipitated silica and fumed silica.

6. The thick rubber foam material with uniform pores according to claim 1, characterized in that: The vulcanizing agent includes any one or more of DCP, DTBP, BPO, BIPB, TBPB, BP, DCBP, bis-24, and bis-25.

7. The thick rubber foam material with uniform pores according to claim 1, characterized in that: The functional material includes one or more of a flame retardant, an anti-aging agent, and an antistatic agent.

8. The method for preparing a thick rubber foam material with uniform pores according to any one of claims 1 to 7, characterized in that: The method comprises the following preparation steps: S1. Thermal Conductive Agent Pretreatment: Stir and mix the thermal conductive agent and silane coupling agent, disperse them ultrasonically, and vacuum dry them to complete the thermal conductive agent pretreatment; S2, step mixing: adding rubber and thermal conductive agent into a mixing device, mixing for 10-15 minutes, then adding reinforcing agent, continuing mixing, then adding hydroxy silicone oil, mixing for 5-8 minutes, to obtain a rubber mixture; S3, pre-vulcanization treatment: After the mixed rubber and the vulcanizing agent are mixed, the roller distance is adjusted to produce a sheet after uniformity, and the sheet is hung to cool and placed after cutting to obtain a film, and the film is placed in a mold and pre-vulcanized to obtain a sheet to be foamed; S4, supercritical foaming: placing the sheet to be foamed in a supercritical foaming device, using supercritical carbon dioxide or nitrogen as a medium, foaming at 65-75°C and 14-16 MPa for 2.5-3.5 hours to obtain a foamed sheet; S5. Segmented vulcanization and shaping: The foamed sheet is vulcanized in segments to prepare a thick rubber foam material with uniform pores.

9. The method for preparing a thick rubber foam material with uniform pores according to claim 8, characterized in that: The pre-vulcanization treatment is as follows: applying a 10T uniform magnetic field in a vulcanization device, and pre-vulcanizing for 6-30 minutes at 125-145°C and 12-14MPa to complete the pre-vulcanization treatment.

10. The method for preparing a thick rubber foam material with uniform pores according to claim 8, characterized in that: The segmented vulcanization shaping comprises the following steps: The first stage vulcanization temperature is 150-180℃, and the time is 10-60min; the second stage vulcanization temperature is 170-190℃, and the time is 30-120min; the third stage vulcanization temperature is 190-210℃, and the time is 60-240min. The foamed sheet is sequentially vulcanized at 150-180° C. for 10-60 min, 170-190° C. for 30-120 min, and 190-210° C. for 60-240 min to prepare a thick rubber foam material with uniform pores.

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