Ultra-soft porous graphene composite block material as well as preparation method and application thereof

Abstract

The invention discloses an ultra-soft porous graphene composite block material as well as a preparation method and application thereof, and belongs to the technical field of graphene heat conduction materials. The preparation method comprises the following steps: uniformly adhering an adhesive to an internal network skeleton of porous graphene to prepare modified porous graphene; flatly paving the modified graphene and pressing at constant pressure to prepare a modified graphene soft sheet; spreading the graphene soft sheet on a crease plate with preset lines, and rolling to form a pre-bending deformation crease, so as to obtain a pre-crease modified graphene soft sheet; spraying an adhesive with target viscosity on the surface of the pre-creased modified graphene soft sheet, and curing to obtain a modified graphene thin-layer composite sheet with cohesiveness on a single surface; and the sheets are aligned along the pre-folding marks to be laminated and flatly laid, pressure is applied, or the sheets are wound with the edge of the side perpendicular to the direction of the pre-folding marks as the center, and the block material of a laminated structure or a roll-shaped structure is formed. The adhesive has the advantages of excellent adhesive property, outstanding ultra-soft compression resistance, excellent and stable heat-conducting property and high process controllability.

Description

Technical Field

[0001] This invention belongs to the field of graphene thermal conductive materials technology, specifically relating to an ultra-soft porous graphene composite bulk material, its preparation method, and its application. Background Technology

[0002] With the rapid development of electronic information technology, chip integration is constantly increasing and computing speed is continuously improving. This has led to a dramatic increase in the heat generated per unit area of ​​electronic devices, making thermal management a core bottleneck restricting the performance improvement and lifespan extension of electronic equipment. Thermal pads, as key gap-filling thermally conductive materials, are widely used between electronic heat-generating devices (such as CPUs, GPUs, and power modules) and heat sinks. Their core function is to fill the microscopic gaps between the contact surfaces and eliminate air at the interface. By achieving a tight fit between the device and the heat sink, they significantly reduce interfacial thermal resistance, thereby maximizing heat conduction efficiency.

[0003] Based on the above application requirements, thermal pads must simultaneously meet two core performance indicators: firstly, excellent thermal conductivity for rapid heat transfer; and secondly, good flexibility and compression recovery to adapt to the microscopic morphological differences of contact surfaces of different devices and achieve gapless adhesion. Traditional thermal pads are mostly made by filling metal powder or ceramic particles with a polymer matrix (such as silicone rubber), but their thermal conductivity is limited by the thermal conductivity and dispersion uniformity of the filler, making it difficult to meet the heat dissipation requirements of high-end electronic devices.

[0004] Graphene, a two-dimensional carbon material with a single atomic layer thickness, boasts an in-plane thermal conductivity of up to 5000 W / (m·K), far exceeding that of traditional metals and ceramics, making it an ideal raw material for preparing high-performance thermal interface materials. Among these, porous graphene (such as graphene foam and graphene aerogel) not only inherits the excellent thermal conductivity of graphene, but its three-dimensional porous structure also endows the material with a certain degree of compressive deformation capability, further meeting the application requirements of thermal pads.

[0005] However, porous graphene materials have inherent performance limitations: on the one hand, they possess extremely high specific surface areas (typically >1000 m²). 2 The graphene sheets are bound together by van der Waals forces, resulting in an imbalance of surface energy and weak hydrophilicity and polarity. Furthermore, the interfacial interactions are weak because the sheets are only bound by van der Waals forces. These two problems directly lead to extremely poor surface adhesion of porous graphene materials, making it easy for the sheets to peel off. This makes it difficult to prepare large-sized, structurally stable bulk materials using traditional molding processes, and further hinders the achievement of tight bonding and integrated molding between the material layers.

[0006] Therefore, how to overcome the bonding bottleneck of porous graphene and prepare an integrated composite bulk material with high thermal conductivity, ultra-softness and compression resistance has become a technical problem that urgently needs to be solved in the field of thermal interface materials, and it is also the core research goal of this invention. Summary of the Invention

[0007] To address the problems existing in current technologies, this invention aims to provide a method for preparing ultra-soft porous graphene composite bulk materials. Through multi-dimensional structural control and interface modification strategies, the method solves the problem of poor interlayer adhesion in graphene, ultimately obtaining a structurally stable and high-performance composite bulk material. This material can then be further processed into thermally conductive pads for use as gap-filling thermal conductive materials. The core innovation of this invention lies in achieving a synergistic improvement in the performance of graphene composite bulk materials through a step-by-step strategy of "internal network modification - flexible control - compression performance optimization - precise interlayer adhesion - integrated molding".

[0008] The objective of this invention is achieved through the following technical solution:

[0009] In a first aspect, the present invention provides a method for preparing an ultrasoft porous graphene composite bulk material, comprising the following steps:

[0010] Preparation of modified porous graphene:

[0011] Porous graphene was immersed in a silicon-based adhesive diluent, then removed horizontally at a uniform speed, and dried and cured at a constant temperature. After the diluent evaporated, the internal network skeleton of the porous graphene was uniformly attached to the cured adhesive, thus obtaining modified porous graphene with improved internal bonding performance.

[0012] Preparation of modified graphene soft sheets:

[0013] Modified porous graphene is laid flat and pressed under constant pressure to improve its internal effective connectivity and flexibility, thus obtaining a modified graphene soft sheet with uniform thickness.

[0014] Preparation of pre-crease modified graphene soft sheets:

[0015] Modified graphene sheets are laid flat on a crease plate with a pre-set texture. The rolling speed is controlled along the pre-set vertical compression direction of the modified graphene sheets to slowly roll and form a pre-bending deformation crease with alternating concave and convex structures to improve the compression deformation capacity in this direction. This structure enables tight interlayer bonding during subsequent composite processes, thus producing a pre-crease modified graphene sheet.

[0016] Preparation of adhesives for spraying:

[0017] After the silicone-based adhesive or the mixture of silicone-based adhesive and composite thermally conductive filler is stirred evenly, defoaming treatment is performed to obtain a spray adhesive with no bubbles and the target viscosity.

[0018] Preparation of modified graphene thin-film composite sheets:

[0019] The adhesive for spraying is transferred to the spray gun. The pre-folded modified graphene sheet is laid flat and fixed on the heating table. The nozzle diameter, spray amplitude, atomization parameters, heating temperature and moving speed of the spray gun are adjusted to control the thickness of the adhesive layer. The adhesive is sprayed onto the surface of the pre-folded modified graphene sheet. After the adhesive is cured, a modified graphene thin-layer composite sheet with adhesive on one side is obtained.

[0020] Preparation of ultrasoft porous graphene composite bulk materials:

[0021] Choose option one or option two;

[0022] Option 1: The modified graphene thin-layer composite material is stacked and laid flat along the pre-fold lines, and then pressure is applied in the preset vertical compression direction. Each layer is tightly interlocked to form a stacked structure of ultra-soft porous graphene composite block material.

[0023] Option 2: Using the edge of the modified graphene thin-layer composite material perpendicular to the pre-crease direction as the center, apply tension and roll it layer by layer to form a roll-shaped ultra-soft porous graphene composite block material.

[0024] Furthermore, in the preparation of modified porous graphene, the porous graphene is selected from one or more of graphene foam, graphene aerogel or graphene sponge.

[0025] The silicone-based adhesive is a thermally conductive liquid gelled silicone, silicone rubber, or organosilicon pressure-sensitive adhesive. The diluent in the silicone-based adhesive diluent is a low-boiling-point silicone oil, methyl methacrylate, ethyl acetate, isopropanol, or ethanol.

[0026] Furthermore, in the preparation of modified porous graphene, the impregnation time of porous graphene is 2s-5s;

[0027] The dilution ratio of the silicone adhesive thinner is 1:(1-6);

[0028] The temperature for constant temperature drying and curing is 50℃-100℃, and the time is 5min-10min.

[0029] Furthermore, in the preparation of modified graphene soft sheets, the pressing pressure under constant pressure is 2t-10t, and the thickness is 0.01mm-0.09mm.

[0030] Furthermore, in the preparation of pre-creased modified graphene soft sheets, the rolling speed is 2 mm / s-10 mm / s.

[0031] Furthermore, in the preparation of the adhesive for spraying, the silicone-based adhesive is a thermally conductive liquid gelled silicone, silicone rubber, or organosilicon pressure-sensitive adhesive;

[0032] The composite thermally conductive filler is one or more of the following: carbon-based filler, metal-based filler, ceramic-based filler, modified carbon-based filler, modified metal-based filler, or modified ceramic-based filler; wherein, the carbon-based filler is selected from graphene or carbon black; the metal-based filler is selected from copper powder, silver powder, silver nanopowder, silicon crystal powder, nano alumina, or nano aluminum nitride; and the ceramic-based filler is nano boron nitride.

[0033] The mixing process uses a high-speed mixer with a speed of 200 r / min-1000 r / min and a mixing time of 2 min-5 min;

[0034] Defoaming is performed using vacuum defoaming or by adding a defoamer. During vacuum defoaming, the vacuum level (gauge pressure) is controlled at -0.1 MPa, and the defoaming time is 2-5 minutes. The amount of defoamer added is 0.1%-0.5% of the total mass of the mixture.

[0035] The target viscosity of the adhesive for spraying is 500 mPa·s-2000 mPa·s.

[0036] Furthermore, in the preparation of modified graphene thin-layer composite sheets, the spray amplitude is adjusted according to the planar dimensions of the thin-layer graphene foam sheet, so that the spray amplitude of the spray gun corresponds to the full coverage of the thin-layer graphene foam sheet plane; the atomization parameters are adjusted by adjusting the air pressure valve to keep the air pressure between 0.2MPa and 0.6MPa; and the nozzle diameter is adjusted to 0.01mm-1mm.

[0037] Adjust the heating table temperature to 50℃-100℃, start the spray gun, and sweep the adhesive onto the surface of the thin graphene foam sheet at a moving speed of 5cm / s-20cm / s to form a uniform adhesive layer with a thickness of 1μm-10μm; the curing time is 1min-5min.

[0038] Furthermore, in the preparation of ultrasoft porous graphene composite bulk materials, the pressure applied in Scheme 1 is 5N-10N; the tensile force in Scheme 2 is 2N / m-10N / m, and the roll structure is a circular or square roll structure bulk material.

[0039] Secondly, the present invention provides an ultra-soft porous graphene composite bulk material, which is prepared by the above-mentioned preparation method of ultra-soft porous graphene composite bulk material to obtain ultra-soft porous graphene composite bulk materials with different stacking structures.

[0040] Thirdly, the present invention provides an application of an ultra-soft porous graphene composite bulk material, which is processed into a thermal pad for filling the gap between electronic heating devices and heat sinks with thermally conductive material.

[0041] Advantages and effects of the present invention:

[0042] (1) Excellent bonding performance: Through the dual bonding strategy of "internal network impregnation modification + uniform surface spraying and tight bonding", a strong chemical and physical bond is formed between graphene sheet layers and material layers, which solves the problems of easy peeling and unstable structure of traditional porous graphene. The bulk material does not crack during vertical compression.

[0043] (2) Outstanding ultra-soft and compression resistant properties: The thinning process improves the flexibility of graphene materials, and the pre-bent crease structure greatly increases the compression deformation and compression recovery rate of the material in the vertical heat conduction direction, which can perfectly adapt to the micro-morphological differences of the contact surfaces of different electronic devices.

[0044] (3) Excellent and stable thermal conductivity: The tight stacking between layers and the construction of directional heat conduction channels can significantly improve the vertical heat transfer efficiency of composite block materials.

[0045] (4) Strong process controllability: The process parameters of each step (such as pressure, temperature, time, etc.) are precisely quantified. The thickness, size and stacking structure of the block material can be adjusted according to actual needs to adapt to the application requirements of different scenarios and facilitate industrial mass production. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the multilayered ultrasoft porous graphene composite bulk material prepared in Example 1;

[0047] Figure 2 This is a schematic diagram of the square roll structure ultrasoft porous graphene composite bulk material prepared in Example 2;

[0048] Figure 3 This is a schematic diagram of the ultra-soft porous graphene composite bulk material with a roll structure prepared in Example 3. Detailed Implementation

[0049] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0050] A method for preparing an ultrasoft porous graphene composite bulk material includes the following steps:

[0051] Preparation of modified porous graphene:

[0052] Porous graphene is immersed in a silicone adhesive diluent for 2-5 seconds, then removed horizontally at a constant speed and dried at a constant temperature of 50℃-100℃ for 5-10 minutes to allow the diluent to fully evaporate. The adhesive is then uniformly attached to the internal network framework of the porous graphene, resulting in modified porous graphene with improved internal bonding performance. The porous graphene is selected from one or more of graphene foam, graphene aerogel, or graphene sponge. The silicone adhesive diluent is obtained by diluting the silicone adhesive with a diluent at a dilution ratio of 1:(1-6). The silicone adhesive is a thermally conductive liquid silicone gel, silicone rubber, or organosilicon pressure-sensitive adhesive, and the diluent is a low-boiling-point silicone oil, methyl methacrylate, ethyl acetate, isopropanol, or ethanol.

[0053] Preparation of modified graphene soft sheets:

[0054] Modified porous graphene is laid flat and further pressed with a constant pressure of 2t-10t to improve its internal effective connectivity and flexibility, resulting in uniform modified graphene soft sheets with a thickness of 0.01mm-0.09mm.

[0055] Preparation of pre-crease modified graphene soft sheets:

[0056] Modified graphene sheets are laid flat on a crease plate with a pre-set texture. The sheets are then slowly rolled at a speed of 2 mm / s to 10 mm / s along the pre-set vertical compression direction to form a pre-bending deformation crease with alternating concave and convex structures. This improves the compression deformation capacity in this direction and enables tight interlayer bonding in the subsequent composite process, thus producing a pre-crease modified graphene sheet.

[0057] Preparation of adhesives for spraying:

[0058] A spray adhesive with no bubbles and a target viscosity of 500 mPa·s-2000 mPa·s is prepared by vacuum defoaming or adding a defoamer to a mixture of silicone-based adhesive or silicone-based adhesive and composite thermally conductive filler.

[0059] The silicone-based adhesive is a thermally conductive liquid gelled silicone, silicone rubber, or pressure-sensitive adhesive; the composite thermally conductive filler is one or more of the following: carbon-based filler, metal-based filler, ceramic-based filler, modified carbon-based filler, modified metal-based filler, or modified ceramic-based filler; wherein the carbon-based filler is selected from graphene or carbon black; the metal-based filler is selected from copper powder, silver powder, silver nanopowder, silicon crystal powder, nano-alumina, or nano-aluminum nitride; and the ceramic-based filler is nano-boron nitride.

[0060] When using a homogeneous mixture of silicone-based adhesive and composite thermally conductive filler, use a high-speed mixer to stir the silicone-based adhesive and composite thermally conductive filler at a speed of 200r / min-1000r / min for 2min-5min;

[0061] When vacuum defoaming is used, the vacuum degree (gauge pressure) is controlled at -0.1MPa, and the defoaming treatment lasts for 2-5 minutes. When defoaming agent is used, the amount of defoaming agent added is 0.1%-0.5% of the total mass of the mixture.

[0062] Preparation of modified graphene thin-film composite sheets:

[0063] Transfer the adhesive to the spray gun hopper. Lay the pre-creased modified graphene sheet flat and fix it on the heating table. Adjust the spray gun's spray amplitude according to the planar dimensions of the graphene foam sheet to cover 100%-110% of its area. Adjust the air pressure valve to maintain an air pressure of 0.2MPa-0.6MPa to control the atomization fineness and ensure the adhesive forms uniform droplets. Adjust the nozzle diameter to 0.01mm-1mm. Set the heating table temperature to 50°C. At ℃-100℃, start the spray gun and spray the adhesive evenly on the surface of the thin graphene foam sheet at a moving speed of 5cm / s-20cm / s to form a uniform adhesive layer with a thickness of 1μm-10μm; maintain the heating temperature and let stand for 1min-5min to allow the adhesive to fully cure, thus obtaining a modified graphene thin-layer composite sheet with adhesive on one side (similar to tape, a thin sheet that is bonded on one side); adjust the nozzle diameter, spray amplitude, atomization parameters, heating temperature and moving speed of the spray gun to control the thickness of the adhesive layer.

[0064] Preparation of ultrasoft porous graphene composite bulk materials:

[0065] Choose option one or option two;

[0066] Option 1: Lay the modified graphene thin-layer composite material in layers along the pre-fold lines, and then apply a pressure of 5N-10N in the preset vertical compression direction. Each layer is tightly interlocked to form a laminated structure of ultra-soft porous graphene composite block material.

[0067] Option 2: Using the edge of the modified graphene thin-layer composite material perpendicular to the pre-crease direction as the center, a tensile force of 2N / m-10N / m is used to tightly wind and interlock the material to form a circular or square roll structure of ultra-soft porous graphene composite block material.

[0068] An ultra-soft porous graphene composite bulk material is prepared using the above-mentioned preparation method for ultra-soft porous graphene composite bulk materials, resulting in ultra-soft porous graphene composite bulk materials with different packing structures.

[0069] An application of an ultra-soft porous graphene composite bulk material is described, in which the ultra-soft porous graphene composite bulk material is processed into a thermally conductive pad for filling the gap between electronic heating devices and heat sinks.

[0070] Example 1

[0071] A method for preparing an ultrasoft porous graphene composite bulk material includes the following steps:

[0072] Preparation of modified porous graphene:

[0073] A graphene foam with an initial thickness of 0.1 mm and a size of 30 cm × 40 cm was immersed in an adhesive dilution solution prepared by mixing silicone rubber and ethyl acetate at a mass ratio of 1:5. After immersion for 2 seconds, it was removed horizontally at a uniform speed and placed on a stainless steel mesh on a 50°C constant temperature heating table. It was left to stand for 5 minutes to allow the solvent to fully evaporate and the cured adhesive to be uniformly attached to the internal network skeleton of the porous graphene, thus obtaining a modified porous graphene foam with improved internal bonding performance.

[0074] Preparation of modified graphene soft sheets:

[0075] The modified porous graphene foam is covered with high-temperature resistant silicone paper on both sides, laid flat between the pressure heads of the tablet press, and pressed into a uniform modified graphene soft sheet with a thickness of 0.03 mm by applying a constant pressure of 2t.

[0076] Preparation of pre-crease modified graphene soft sheets:

[0077] Modified graphene sheets are laid flat on a crease plate with 1mm spacing. The sheets are rolled at a speed of 2mm / s along the preset vertical compression direction to form pre-bending deformation creases with alternating concave and convex structures in the vertical compression direction, thus producing pre-crease modified graphene sheets.

[0078] Preparation of adhesives for spraying:

[0079] Silicone rubber was added to a high-speed mixer and stirred at 200 r / min for 2 min. Then, a vacuum defoaming method was used to control the vacuum degree (gauge pressure) to -0.1 MPa and defoaming for 2 min to obtain a bubble-free spray adhesive with a viscosity of 500 mPa·s.

[0080] Preparation of modified graphene thin-film composite sheets:

[0081] Transfer the adhesive for spraying into the spray gun hopper. Lay the pre-creased modified graphene sheet flat and fix it on the 80℃ heating table. Adjust the nozzle diameter to 0.01mm, the air pressure to 0.2MPa, and set the spraying width to cover an area of ​​31cm×41cm, fully covering the pre-creased modified graphene sheet. Start the spray gun and sweep the adhesive across the surface of the pre-creased modified graphene sheet at a moving speed of 20cm / s to form a uniform adhesive layer with a thickness of 1μm. Maintain the heating temperature and let it stand for 1 minute to allow the adhesive to fully cure, thus obtaining a single-layer modified graphene thin-layer composite material with stable interlayer bonding.

[0082] Preparation of ultrasoft porous graphene composite bulk materials:

[0083] Modified graphene thin-layer composite materials are stacked with fold lines aligned, and then compacted layer by layer under a pressure of 5N to obtain a stacked structure of ultra-soft porous graphene composite bulk material.

[0084] The supersoft porous graphene composite bulk material stacked structure prepared in Example 1 is as follows: Figure 1 As shown.

[0085] Example 2

[0086] A method for preparing an ultrasoft porous graphene composite bulk material includes the following steps:

[0087] Preparation of modified porous graphene:

[0088] A graphene aerogel with an initial thickness of 0.09 mm was immersed in an adhesive dilution solution prepared by mixing thermally conductive liquid gelling silica gel and methyl methacrylate at a mass ratio of 1:4. After immersion for 5 seconds, it was removed horizontally at a uniform speed and placed on a stainless steel mesh on a 70℃ constant temperature heating table. It was left to stand for 8 minutes to allow the solvent to fully evaporate and the solidified adhesive to be uniformly attached to the internal network skeleton of the porous graphene, thus obtaining a modified porous graphene aerogel with improved internal bonding performance.

[0089] Preparation of modified graphene soft sheets:

[0090] The modified porous graphene aerogel was covered with high-temperature resistant silicone paper on both sides, laid flat between the pressure heads of a tablet press, and pressed into a uniform modified graphene soft sheet with a thickness of 0.04 mm by applying a constant pressure of 3t.

[0091] Preparation of pre-crease modified graphene soft sheets:

[0092] The modified graphene sheet is laid flat on a crease plate with 1mm spacing. The modified graphene sheet is rolled at a speed of 8mm / s along the preset vertical compression direction using a rolling device to form a pre-bending deformation crease with alternating concave and convex structures in the vertical compression direction, thus producing a pre-crease modified graphene sheet.

[0093] Preparation of adhesives for spraying:

[0094] Weigh thermally conductive silicone and nano boron nitride powder at a mass ratio of 4:1, add them to a high-speed mixer and stir at 800 r / min for 4 min to obtain a uniform mixture. Add 0.3% of the total mass of the mixture as defoamer to obtain a bubble-free spray adhesive with a viscosity of 1000 mPa·s.

[0095] Preparation of modified graphene thin-film composite sheets:

[0096] Transfer the adhesive for spraying into the spray gun hopper. Lay the pre-creased modified graphene sheet flat and fix it on the 80℃ heating table. Adjust the nozzle diameter to 0.05mm and the air pressure to 0.5MPa. Spray the adhesive to fully cover the pre-creased modified graphene sheet. Start the spray gun and sweep the adhesive across the surface of the pre-creased modified graphene sheet at a moving speed of 5cm / s to form a uniform adhesive layer with a thickness of 5μm. Maintain the heating temperature and let it stand for 5 minutes to allow the adhesive to fully cure, thus obtaining a single-layer modified graphene thin-layer composite material with stable interlayer bonding.

[0097] Preparation of ultrasoft porous graphene composite bulk materials:

[0098] Centered on one edge of the modified graphene thin-layer composite material perpendicular to the pre-crease direction, it is tightly wound and bonded with a tensile force of 2 N / m to form a square roll structure of ultra-soft porous graphene composite block material.

[0099] The ultrasoft porous graphene composite bulk material prepared in Example 2 has a cube structure as shown in the figure. Figure 2 As shown.

[0100] Example 3

[0101] A method for preparing an ultrasoft porous graphene composite bulk material includes the following steps:

[0102] Preparation of modified porous graphene:

[0103] A graphene sponge with an initial thickness of 0.1 mm was immersed in an adhesive dilution solution prepared by mixing organosilicon pressure-sensitive adhesive and low-boiling-point silicone oil at a mass ratio of 1:2. After immersion for 3 seconds, it was removed horizontally at a uniform speed and placed on a stainless steel mesh on a 100℃ constant temperature heating table. It was left to stand for 10 minutes to allow the solvent to fully evaporate and the cured adhesive to be uniformly attached to the internal network skeleton of the porous graphene, thus obtaining a modified porous graphene sponge with improved internal bonding performance.

[0104] Preparation of modified graphene soft sheets:

[0105] The modified porous graphene sponge is covered with high-temperature resistant silicone paper on both sides, laid flat between the pressure heads of the tablet press, and pressed into a uniform modified graphene soft sheet with a thickness of 0.01 mm by applying a constant pressure of 10t.

[0106] Preparation of pre-crease modified graphene soft sheets:

[0107] Modified graphene sheets are laid flat on a crease plate with 0.5mm spacing. The sheets are rolled at a speed of 10mm / s along the preset vertical compression direction to form pre-bending deformation creases with alternating concave and convex structures in the vertical compression direction, thus producing pre-crease modified graphene sheets.

[0108] Preparation of adhesives for spraying:

[0109] Weigh out the silicone pressure-sensitive adhesive and micron copper powder at a mass ratio of 5:1, put them into a high-speed mixer and stir at 1000 r / min for 2 min to obtain a uniform mixture. Then, use the vacuum defoaming method to control the vacuum degree (gauge pressure) to -0.1 MPa and defoam for 5 min to obtain a bubble-free spray adhesive with a viscosity of 2000 mPa·s.

[0110] Preparation of modified graphene thin-film composite sheets:

[0111] Transfer the adhesive for spraying into the spray gun hopper. Lay the pre-creased modified graphene sheet flat and fix it on a 70℃ heating table. Adjust the nozzle diameter to 1mm and the air pressure to 0.6MPa. Spray the adhesive to fully cover the pre-creased modified graphene sheet. Start the spray gun and sweep the adhesive across the surface of the pre-creased modified graphene sheet at a moving speed of 10cm / s to form a uniform adhesive layer with a thickness of 2μm. Maintain the heating temperature and let it stand for 3 minutes to allow the adhesive to fully cure, thus obtaining a single-layer modified graphene thin-layer composite material with stable interlayer bonding.

[0112] Preparation of ultrasoft porous graphene composite bulk materials:

[0113] Centered on one edge of the modified graphene thin-layer composite material perpendicular to the pre-crease direction, a tensile force of 10 N / m is used to tightly wrap and bond the material, forming a roll-shaped ultra-soft porous graphene composite block material.

[0114] The ultrasoft porous graphene composite bulk material with a roll structure prepared in Example 3 is as follows: Figure 3 As shown.

[0115] Example 4

[0116] A method for preparing an ultrasoft porous graphene composite bulk material includes the following steps:

[0117] Preparation of modified porous graphene:

[0118] A graphene aerogel with an initial thickness of 0.08 mm was immersed in an adhesive dilution solution prepared by mixing thermally conductive liquid gelling silica gel and methyl methacrylate at a mass ratio of 1:6. After immersion for 5 seconds, it was removed horizontally at a uniform speed and placed on a stainless steel mesh on a 60℃ constant temperature heating table. It was left to stand for 6 minutes to allow the solvent to fully evaporate and the solidified adhesive to be uniformly attached to the internal network skeleton of the porous graphene, thus obtaining a modified porous graphene aerogel with improved internal bonding performance.

[0119] Preparation of modified graphene soft sheets:

[0120] The modified porous graphene aerogel was covered with high-temperature resistant silicone paper on both sides, laid flat between the pressure heads of a tablet press, and pressed into a uniform modified graphene soft sheet with a thickness of 0.09 mm by applying a constant pressure of 5t.

[0121] Preparation of pre-crease modified graphene soft sheets:

[0122] Modified graphene sheets are laid flat on a crease plate with 1mm spacing. The sheets are rolled at a speed of 5mm / s along the preset vertical compression direction to form pre-bending deformation creases with alternating concave and convex structures in the vertical compression direction, thus producing pre-crease modified graphene sheets.

[0123] Preparation of adhesives for spraying:

[0124] Weigh thermally conductive gelling silicone and nano-aluminum powder at a mass ratio of 4:1, put them into a high-speed mixer and stir at 300 r / min for 3 min to obtain a uniform mixture. Then, use a vacuum defoaming method to control the vacuum degree (gauge pressure) to -0.1 MPa and defoam for 3 min to obtain a bubble-free spray adhesive with a viscosity of 800 mPa·s.

[0125] Preparation of modified graphene thin-film composite sheets:

[0126] Transfer the adhesive for spraying into the spray gun hopper. Lay the pre-creased modified graphene sheet flat and fix it on a 50℃ heating table. Adjust the nozzle diameter to 0.01mm and the air pressure to 0.5MPa. Spray the adhesive to fully cover the pre-creased modified graphene sheet. Start the spray gun and sweep the adhesive across the surface of the pre-creased modified graphene sheet at a moving speed of 15cm / s to form a uniform adhesive layer with a thickness of 6μm. Maintain the heating temperature and let it stand for 2 minutes to allow the adhesive to fully cure, thus obtaining a single-layer modified graphene thin-layer composite material with stable interlayer bonding.

[0127] Preparation of ultrasoft porous graphene composite bulk materials:

[0128] Modified graphene thin-layer composite materials are stacked with fold lines aligned, and then compacted layer by layer under a pressure of 10N to obtain a stacked structure of ultra-soft porous graphene composite bulk material.

[0129] Example 5

[0130] A method for preparing an ultrasoft porous graphene composite bulk material includes the following steps:

[0131] Preparation of modified porous graphene:

[0132] A graphene foam with an initial thickness of 0.1 mm and a size of 200 cm × 100 cm was immersed in an adhesive dilution solution prepared by mixing organosilicon pressure-sensitive adhesive and low-boiling-point silicone oil at a mass ratio of 1:3. After immersion for 5 seconds, it was removed horizontally at a uniform speed and placed on a stainless steel mesh on an 80°C constant-temperature heating platform. It was left to stand for 5 minutes to allow the solvent to fully evaporate and the cured adhesive to be uniformly attached to the internal network skeleton of the porous graphene, thus obtaining a modified porous graphene foam with improved internal bonding performance.

[0133] Preparation of modified graphene soft sheets:

[0134] The modified porous graphene foam is covered with high-temperature resistant silicone paper on both sides, laid flat between the pressure heads of the tablet press, and pressed into a uniform modified graphene soft sheet with a thickness of 0.05 mm by applying a constant pressure of 6t.

[0135] Preparation of pre-crease modified graphene soft sheets:

[0136] Modified graphene sheets are laid flat on a crease plate with 1mm spacing. The sheets are rolled at a speed of 5mm / s along the preset vertical compression direction to form pre-bending deformation creases with alternating concave and convex structures in the vertical compression direction, thus producing pre-crease modified graphene sheets.

[0137] Preparation of adhesives for spraying:

[0138] Weigh out silicone pressure-sensitive adhesive, silver nanoparticles and nano boron nitride in a mass ratio of 2:1:1, put them into a high-speed mixer and stir at 500 r / min for 5 min to obtain a uniform mixture. Then, use a vacuum defoaming method to control the vacuum degree (gauge pressure) to -0.1 MPa and defoam for 5 min to obtain a bubble-free spray adhesive with a viscosity of 1500 mPa·s.

[0139] Preparation of modified graphene thin-film composite sheets:

[0140] Transfer the adhesive for spraying into the spray gun hopper. Lay the pre-creased modified graphene sheet flat and fix it on the 100℃ heating table. Adjust the nozzle diameter to 0.08mm and the air pressure to 0.2MPa. Set the spraying width to cover an area of ​​202cm×102cm, fully covering the pre-creased modified graphene sheet. Start the spray gun and sweep the adhesive across the surface of the pre-creased modified graphene sheet at a moving speed of 20cm / s to form a uniform adhesive layer with a thickness of 10μm. Maintain the heating temperature and let it stand for 5 minutes to allow the adhesive to fully cure, thus obtaining a single-layer modified graphene thin-layer composite material with stable interlayer bonding.

[0141] Preparation of ultrasoft porous graphene composite bulk materials:

[0142] Centered on one edge of the modified graphene thin-layer composite material perpendicular to the pre-crease direction, a tight-fitting, tightly bonded roll is formed by winding with a tensile force of 5 N / m to create an ultra-soft porous graphene composite block material with a roll structure.

[0143] Example 6

[0144] A method for preparing an ultrasoft porous graphene composite bulk material includes the following steps:

[0145] Preparation of modified porous graphene:

[0146] A graphene foam with an initial thickness of 0.1 mm and a size of 20 cm × 60 cm was immersed in an adhesive dilution solution prepared by mixing silicone rubber and low-boiling-point silicone oil at a mass ratio of 1:2. After immersion for 3 seconds, it was removed horizontally at a uniform speed and placed on a stainless steel mesh on a 60°C constant-temperature heating table. It was left to stand for 8 minutes to allow the solvent to fully evaporate and the cured adhesive to be uniformly attached to the internal network skeleton of the porous graphene, thus obtaining a modified porous graphene foam with improved internal bonding performance.

[0147] Preparation of modified graphene soft sheets:

[0148] The modified porous graphene foam is covered with high-temperature resistant silicone paper on both sides, laid flat between the pressure heads of the tablet press, and pressed into a uniform modified graphene soft sheet with a thickness of 0.02 mm by applying a constant pressure of 4t.

[0149] Preparation of pre-crease modified graphene soft sheets:

[0150] Modified graphene sheets are laid flat on a crease plate with 1mm spacing. The sheets are rolled at a speed of 2mm / s along the preset vertical compression direction to form pre-bending deformation creases with alternating concave and convex structures in the vertical compression direction, thus producing pre-crease modified graphene sheets.

[0151] Preparation of adhesives for spraying:

[0152] Weigh out silicone rubber and nano silver powder at a mass ratio of 3:1, put them into a high-speed mixer and stir at 1000 r / min for 3 min to obtain a uniform mixture. Then, use a vacuum defoaming method to control the vacuum degree (gauge pressure) to -0.1 MPa and defoam for 3 min to obtain a bubble-free spray adhesive with a viscosity of 600 mPa·s.

[0153] Preparation of modified graphene thin-film composite sheets:

[0154] Transfer the adhesive for spraying into the spray gun hopper. Lay the pre-creased modified graphene sheet flat and fix it on a 60℃ heating table. Adjust the nozzle diameter to 0.03mm and the air pressure to 0.6MPa. Set the spraying width to cover an area of ​​21cm×61cm, fully covering the pre-creased modified graphene sheet. Start the spray gun and sweep the adhesive across the surface of the pre-creased modified graphene sheet at a moving speed of 6cm / s to form a uniform adhesive layer with a thickness of 4μm. Maintain the heating temperature and let it stand for 4 minutes to allow the adhesive to fully cure, thus obtaining a single-layer modified graphene thin-layer composite material with stable interlayer bonding.

[0155] Preparation of ultrasoft porous graphene composite bulk materials:

[0156] Modified graphene thin-layer composite materials are stacked with fold lines aligned, and then compacted layer by layer under 8N pressure to obtain a stacked structure of ultra-soft porous graphene composite bulk material.

[0157] Example 7

[0158] A method for preparing an ultrasoft porous graphene composite bulk material includes the following steps:

[0159] Preparation of modified porous graphene:

[0160] A graphene sponge with an initial thickness of 0.1 mm was immersed in an adhesive dilution solution prepared by mixing organosilicon pressure-sensitive adhesive and isopropanol at a mass ratio of 1:1. After immersion for 3 seconds, it was removed horizontally at a uniform speed and placed on a stainless steel mesh on a 100℃ constant temperature heating table. It was left to stand for 10 minutes to allow the solvent to fully evaporate and the cured adhesive to be uniformly attached to the internal network skeleton of the porous graphene, thus obtaining a modified porous graphene sponge with improved internal bonding performance.

[0161] Preparation of modified graphene soft sheets:

[0162] The modified porous graphene sponge is covered with high-temperature resistant silicone paper on both sides, laid flat between the pressure heads of the tablet press, and pressed into a uniform modified graphene soft sheet with a thickness of 0.01 mm by applying a constant pressure of 10t.

[0163] Preparation of pre-crease modified graphene soft sheets:

[0164] Modified graphene sheets are laid flat on a crease plate with 0.5mm spacing. The sheets are rolled at a speed of 10mm / s along the preset vertical compression direction to form pre-bending deformation creases with alternating concave and convex structures in the vertical compression direction, thus producing pre-crease modified graphene sheets.

[0165] Preparation of adhesives for spraying:

[0166] Weigh out the silicone pressure-sensitive adhesive and micronized carbon black powder at a mass ratio of 1:1, put them into a high-speed mixer and stir at 800 r / min for 4 min to obtain a uniform mixture. Then, use a vacuum defoaming method to control the vacuum degree (gauge pressure) to -0.1 MPa and defoam for 3 min to obtain a bubble-free spray adhesive with a viscosity of 600 mPa·s.

[0167] Preparation of modified graphene thin-film composite sheets:

[0168] Transfer the adhesive for spraying into the spray gun hopper. Lay the pre-creased modified graphene sheet flat and fix it on a 90℃ heating table. Adjust the nozzle diameter to 0.08mm and the air pressure to 0.2MPa. Spray the adhesive to fully cover the pre-creased modified graphene sheet. Start the spray gun and sweep the adhesive across the surface of the pre-creased modified graphene sheet at a moving speed of 12cm / s to form a uniform adhesive layer with a thickness of 6μm. Maintain the heating temperature and let it stand for 5 minutes to allow the adhesive to fully cure, thus obtaining a single-layer modified graphene thin-layer composite material with stable interlayer bonding.

[0169] Preparation of ultrasoft porous graphene composite bulk materials:

[0170] Centered on one edge of the modified graphene thin-layer composite material perpendicular to the pre-crease direction, a tensile force of 6 N / m is used to tightly wrap and bond the material, forming a square roll structure of ultra-soft porous graphene composite block material.

Claims

1. A method for preparing an ultrasoft porous graphene composite bulk material, characterized in that, Includes the following steps: Preparation of modified porous graphene: Porous graphene was immersed in a silicon-based adhesive diluent, then removed horizontally at a uniform speed and dried and cured at a constant temperature. The adhesive was uniformly attached to the internal network framework of the porous graphene, thus obtaining modified porous graphene with improved internal bonding performance. Preparation of modified graphene soft sheets: Modified porous graphene is laid flat and pressed under constant pressure to obtain a soft sheet of modified graphene with uniform thickness. Preparation of pre-crease modified graphene soft sheets: The modified graphene sheet is laid flat on a crease plate with a preset texture. The rolling speed is controlled along the preset vertical compression direction of the modified graphene sheet to slowly roll and form a pre-bending deformation crease with alternating concave and convex structures, thus producing a pre-crease modified graphene sheet. Preparation of adhesives for spraying: After the silicone-based adhesive or the mixture of silicone-based adhesive and composite thermally conductive filler is stirred evenly, defoaming treatment is performed to obtain a spray adhesive with no bubbles and the target viscosity. Preparation of modified graphene thin-film composite sheets: The adhesive for spraying is transferred to the spray gun. The pre-folded modified graphene sheet is laid flat and fixed on the heating table. The nozzle diameter, spray amplitude, atomization parameters, heating temperature and moving speed of the spray gun are adjusted to spray the adhesive onto the surface of the pre-folded modified graphene sheet. After the adhesive is cured, a modified graphene thin-layer composite sheet with adhesive on one side is obtained. Preparation of ultrasoft porous graphene composite bulk materials: Choose option one or option two; Option 1: The modified graphene thin-layer composite material is stacked and laid flat along the pre-fold lines, and then pressure is applied in the preset vertical compression direction. Each layer is tightly interlocked to form a stacked structure of ultra-soft porous graphene composite block material. Option 2: Using the edge of the modified graphene thin-layer composite material perpendicular to the pre-crease direction as the center, apply tension and roll it up layer by layer to form a roll-shaped ultra-soft porous graphene composite block material.

2. The method for preparing an ultrasoft porous graphene composite bulk material as described in claim 1, characterized in that, In the preparation of modified porous graphene, the porous graphene is selected from one or more of graphene foam, graphene aerogel or graphene sponge. The silicone-based adhesive is a thermally conductive liquid gelled silicone, silicone rubber, or organosilicon pressure-sensitive adhesive. The diluent in the silicone-based adhesive diluent is a low-boiling-point silicone oil, methyl methacrylate, ethyl acetate, isopropanol, or ethanol.

3. The method for preparing an ultrasoft porous graphene composite bulk material as described in claim 1, characterized in that, In the preparation of modified porous graphene, the impregnation time of porous graphene is 2s-5s; The dilution ratio of the silicone adhesive thinner is 1:(1-6); The temperature for constant temperature drying and curing is 50℃-100℃, and the time is 5min-10min.

4. The method for preparing an ultrasoft porous graphene composite bulk material as described in claim 1, characterized in that, In the preparation of modified graphene soft sheets, the pressing pressure under constant pressure is 2t-10t, and the thickness is 0.01mm-0.09mm.

5. The method for preparing an ultrasoft porous graphene composite bulk material as described in claim 1, characterized in that, In the preparation of pre-creased modified graphene soft sheets, the rolling speed is 2 mm / s-10 mm / s.

6. The method for preparing an ultrasoft porous graphene composite bulk material as described in claim 1, characterized in that, In the preparation of adhesives for spraying, the silicone-based adhesive is a thermally conductive liquid gelled silicone, silicone rubber, or organosilicon pressure-sensitive adhesive. The composite thermally conductive filler is one or more of the following: carbon-based filler, metal-based filler, ceramic-based filler, modified carbon-based filler, modified metal-based filler, or modified ceramic-based filler; wherein, the carbon-based filler is selected from graphene or carbon black; the metal-based filler is selected from copper powder, silver powder, silver nanopowder, silicon crystal powder, nano alumina, or nano aluminum nitride; and the ceramic-based filler is nano boron nitride. The mixing process uses a high-speed mixer with a speed of 200 r / min-1000 r / min and a mixing time of 2 min-5 min; Defoaming is performed using vacuum defoaming or by adding a defoaming agent. During vacuum defoaming, the vacuum gauge pressure is controlled at -0.1 MPa, and the defoaming process lasts 2-5 minutes. The amount of defoaming agent added is 0.1%-0.5% of the total mass of the mixture. The target viscosity of the adhesive for spraying is 500 mPa·s-2000 mPa·s.

7. The method for preparing an ultrasoft porous graphene composite bulk material as described in claim 1, characterized in that, In the preparation of modified graphene thin-layer composite sheets, the spray amplitude is adjusted according to the planar dimensions of the thin-layer graphene foam sheet, so that the spray amplitude of the spray gun corresponds to the full coverage of the thin-layer graphene foam sheet plane; the atomization parameters are adjusted by adjusting the air pressure valve to keep the air pressure between 0.2MPa and 0.6MPa; and the nozzle diameter is adjusted to 0.01mm-1mm. Adjust the heating table temperature to 50℃-100℃, start the spray gun, and sweep the adhesive onto the surface of the thin graphene foam sheet at a moving speed of 5cm / s-20cm / s to form a uniform adhesive layer with a thickness of 1μm-10μm; the curing time is 1min-5min.

8. The method for preparing an ultrasoft porous graphene composite bulk material as described in claim 1, characterized in that, In the preparation of ultrasoft porous graphene composite bulk materials, the pressure applied in Scheme 1 is 5N-10N; the tensile force in Scheme 2 is 2N / m-10N / m, and the rolled structure is a circular or square roll structure bulk material.

9. A supersoft porous graphene composite bulk material, characterized in that, The ultra-soft porous graphene composite bulk material was prepared using the preparation method of any one of claims 1-8, and ultra-soft porous graphene composite bulk materials with different stacking structures were obtained.

10. An application of the ultrasoft porous graphene composite bulk material according to claim 9, characterized in that, Ultra-soft porous graphene composite bulk material is processed into thermal pads for filling the gaps between electronic heating devices and heat sinks.

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