Carbon fiber long fiber heat conducting gasket, its preparation method and application

Abstract

The application discloses a carbon fiber long fiber heat-conducting gasket and a preparation method and application thereof. Raw materials include, in parts by weight, methyl vinyl silicone rubber 8-10 parts, vinyl silicone oil 20-25 parts, dimethyl silicone oil 10-12 parts, hydrogen-containing silicone oil 2-4 parts, carbon fiber long fiber 55-60 parts, a catalyst 1-2 parts, an inhibitor 0.05-0.1 parts and a coupling agent 0.5-1.0 parts. The heat-conducting gasket has low Shore hardness and compression clamping stress, high steady-state thermal conductivity and small steady-state contact thermal resistance, has a self-adapting reversible structure, can realize carbon fiber long fiber tilt 30-45° slip drag reduction in the process of optical module insertion, and can realize long fiber automatic reset to 90° vertical orientation after optical module pulling-out unloading, 100% rebound without permanent deformation, perfect adaptation to high-frequency insertion and extraction heat dissipation of high-speed optical modules and long-term stable working scenes.

Description

Technical Field

[0001] This invention belongs to the technical field of thermal conductive materials for optical module thermal interfaces, specifically relating to a carbon fiber long-fiber thermal conductive pad, its preparation method and application, and in particular, a carbon fiber long-fiber thermal conductive pad, its preparation method and its application in the field of heat dissipation during optical module insertion and removal. Background Technology

[0002] Currently, high-speed optical modules are iterating towards 400G, 800G, and 1.6T ultra-high speeds and high power consumption, resulting in a sharp increase in device heat flux density. At the same time, frequent plugging and unplugging is required in operation and maintenance scenarios, which puts forward stringent requirements on thermal interface materials, such as ultra-low clamping stress, extremely low contact thermal resistance, 100% springback resistance to plugging and unplugging, no device damage, and stable heat dissipation without drift.

[0003] Traditional optical module thermal pads have fixed structures and formulations, making them unsuitable for high-frequency plugging and unplugging scenarios requiring high-reliability heat dissipation. They generally suffer from the following technical challenges:

[0004] (1) Traditional powder-filled silicone thermal pads have a large amount of substrate filling, which has disadvantages such as poor rebound, high hardness and large compression modulus. The assembly clamping stress is high, the frictional resistance is large and the assembly stress is concentrated during the insertion and removal of optical modules. Long-term repeated insertion and removal can easily cause problems such as optical module shell deformation, gold finger micro-deformation and cavity offset, which ultimately lead to abnormal optical link insertion loss, optical power attenuation and device failure.

[0005] (2) Existing short-cut carbon fiber thermal pads adopt a disordered mixed filling structure. The material is isotropic as a whole. After being compressed, it has no adaptive tilt angle sliding ability. The insertion and removal resistance is large, and the elastic recovery is significantly delayed. After repeated insertion and removal, it is easy to produce irreversible permanent deformation, resulting in the breakage of the thermal conduction path, a large drift of the contact thermal resistance, and extremely poor long-term heat dissipation stability.

[0006] (3) In order to achieve a high thermal conductivity of more than 20 W / (m·K), a high proportion of hard ceramic powders such as alumina and aluminum nitride are usually filled into the thermal pads. This results in loss of matrix flexibility, material stiffness, a significant decrease in resilience, and a significant increase in compressive stress, forming an industry technical contradiction of "high thermal conductivity must be high stress, and low stress must be low thermal conductivity". It is impossible to meet the core requirements of high thermal conductivity and low stress non-destructive plugging and unplugging of optical modules.

[0007] In summary, there is currently a lack of a dedicated thermal pad for optical modules that combines ultra-soft and ultra-low stress, 100% full resilience, plug-in adaptive tilt reversible structure, long fiber continuous high thermal conductivity, and ultra-low steady-state thermal resistance, which restricts the iterative upgrade and long-term stable operation and maintenance of high-speed optical communication modules. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a carbon fiber long-fiber thermal conductive pad, its preparation method, and its application.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a carbon fiber long fiber thermal conductive pad, wherein, by weight, the raw materials include 8-10 parts of methyl vinyl silicone rubber, 20-25 parts of vinyl silicone oil, 10-12 parts of dimethyl silicone oil, 2-4 parts of hydrogen-containing silicone oil, 55-60 parts of carbon fiber long fiber, 1-2 parts of catalyst, 0.05-0.1 parts of inhibitor and 0.5-1.0 parts of coupling agent.

[0011] Compared to existing optical module thermal pads, which suffer from high insertion and extraction resistance, high clamping stress, poor resilience, poor thermal resistance stability, susceptibility to permanent deformation, and low long-term reliability, this invention completely solves the technical contradiction between high thermal conductivity and low stress and high resilience by using continuous carbon fiber long fibers as the single thermal conductive medium, combined with a compound ultra-soft, flexible, and highly resilient matrix of dimethyl silicone oil, low-viscosity vinyl silicone oil, and methyl vinyl silicone oil.

[0012] The long fibers in the carbon fiber thermal conductive pad of the present invention are carbon fibers arranged in the same direction. By combining vertical pre-orientation and low-temperature molding process, the technical contradiction between high thermal conductivity and low stress and high resilience can be completely solved.

[0013] The thermal pad provided by this invention has both low Shore hardness and compressive clamping stress, high steady-state thermal conductivity and low steady-state contact thermal resistance. It also has an adaptive and reversible structure, which can achieve drag reduction by tilting the carbon fiber long fiber at 30-45° during the insertion of the optical module. After the optical module is pulled out and the force is released, the long fiber automatically returns to a 90° vertical orientation, with 100% springback and no permanent deformation. It is perfectly adapted to the high-frequency insertion and removal heat dissipation and long-term stable operation scenarios of high-speed optical modules.

[0014] In this invention, the methyl vinyl silicone rubber comprises 8-10 parts, such as 8 parts, 8.5 parts, 9 parts, 9.5 parts, 10 parts, etc., but is not limited to the listed values. Other unlisted values ​​or ranges within the numerical range are also applicable. The vinyl silicone oil comprises 20-25 parts, such as 20 parts, 21 parts, 22 parts, 23 parts, 24 parts, 25 parts, etc., but is not limited to the listed values. Other unlisted values ​​or ranges within the numerical range are also applicable. The dimethyl silicone oil comprises 10-12 parts, such as 10 parts, 10.5 parts, 11 parts, 11.5 parts, 12 parts, etc., but is not limited to the listed values. Other unlisted values ​​or ranges within the numerical range are also applicable. The hydrogen-containing silicone oil comprises 2-4 parts, such as 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, etc., but is not limited to the listed values. Other unlisted values ​​or ranges within the numerical range are also applicable. The carbon fiber long fiber comprises 5 parts. 5-60 parts, such as 55, 56, 57, 58, 59, 60 parts, etc., but not limited to the listed values. Other unlisted point values ​​or ranges within the value range are also applicable. Catalyst 1-2 parts, such as 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, etc., but not limited to the listed values. Other unlisted point values ​​or ranges within the value range are also applicable. Inhibitor 0.05-0.1 parts, such as 0.05 parts, 0.06 parts, 0.07 parts, 0.08 parts, 0.09 parts, 0.1 parts, etc., but not limited to the listed values. Other unlisted point values ​​or ranges within the value range are also applicable. Coupling agent 0.5-1.0 parts, such as 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1.0 parts, etc., but not limited to the listed values. Other unlisted point values ​​or ranges within the value range are also applicable.

[0015] Preferably, in the thermally conductive pad, the long carbon fiber fibers are arranged vertically in the Z-direction, giving the thermally conductive pad excellent thermal conductivity with a thermal conductivity ≥20 W / (m·K), such as 20 W / (m·K), 21 W / (m·K), 22 W / (m·K), 23 W / (m·K), 24 W / (m·K), 25 W / (m·K), 26 W / (m·K), 27 W / (m·K), 28 W / (m·K), 29 W / (m·K), 30 W / (m·K), etc., but not limited to the listed values. Other unlisted point values ​​or range values ​​within the value range are also applicable.

[0016] Preferably, the Shore 00 hardness of the carbon fiber long-fiber thermal conductive pad is ≤20, such as 20, 18, 16, 15, 14, 12, 10, 9, 8, 7, 5, etc., but not limited to the listed values. Other unlisted point values ​​or range values ​​within the value range are also applicable.

[0017] Preferably, the compression clamping stress of the carbon fiber thermal conductive pad is ≤5 psi, such as 5 psi, 4.8 psi, 4.5 psi, 4.2 psi, 4 psi, 3.8 psi, 3.5 psi, 3.2 psi, 3 psi, 2.8 psi, 2.5 psi, 2 psi, etc., but not limited to the listed values. Other unlisted point values ​​or range values ​​within the numerical range are also applicable.

[0018] Preferably, the resilience of the carbon fiber long-fiber thermal conductive pad is ≥99.9%.

[0019] Preferably, the Mooney viscosity of the methyl vinyl silicone rubber is 40-70 Mooney, such as 40 Mooney, 42 Mooney, 45 Mooney, 48 Mooney, 50 Mooney, 52 Mooney, 55 Mooney, 58 Mooney, 60 Mooney, 65 Mooney, 70 Mooney, etc., but is not limited to the listed values. Other unlisted point values ​​or range values ​​within the numerical range are also applicable.

[0020] Preferably, the vinyl content of the methyl vinyl silicone rubber is 0.1-0.5 wt%, such as 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, etc., but is not limited to the listed values. Other unlisted point values ​​or range values ​​within the value range are also applicable.

[0021] Preferably, the viscosity of the vinyl silicone oil is 100-200 mPa·s, such as 100 mPa·s, 110 mPa·s, 120 mPa·s, 130 mPa·s, 140 mPa·s, 150 mPa·s, 160 mPa·s, 170 mPa·s, 180 mPa·s, 190 mPa·s, 200 mPa·s, etc., but is not limited to the listed values. Other unlisted point values ​​or range values ​​within the numerical range are also applicable.

[0022] Preferably, the vinyl content of the vinyl silicone oil is 1-3 wt%, such as 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, etc., but not limited to the listed values. Other unlisted point values ​​or range values ​​within the value range are also applicable.

[0023] Preferably, the viscosity of the dimethyl silicone oil is 100-200 mPa·s, such as 100 mPa·s, 110 mPa·s, 120 mPa·s, 130 mPa·s, 140 mPa·s, 150 mPa·s, 160 mPa·s, 170 mPa·s, 180 mPa·s, 190 mPa·s, 200 mPa·s, etc., but is not limited to the listed values. Other unlisted point values ​​or range values ​​within the numerical range are also applicable.

[0024] Preferably, the viscosity of the hydrogen-containing silicone oil is 20-40 mPa·s, such as 20 mPa·s, 22 mPa·s, 25 mPa·s, 28 mPa·s, 30 mPa·s, 32 mPa·s, 35 mPa·s, 38 mPa·s, 40 mPa·s, etc., but not limited to the listed values. Other unlisted point values ​​or range values ​​within the numerical range are also applicable. The hydrogen content is 0.1-0.5 wt%, such as 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, etc., but not limited to the listed values. Other unlisted point values ​​or range values ​​within the numerical range are also applicable.

[0025] Preferably, the catalyst comprises a platinum-based catalyst, and more preferably any one or a combination of at least two of the following: isopropanol chloroplatinate complex, platinum-1,3-divinyltetramethyldisiloxane complex (Karstedt catalyst), or platinum cyclic olefin complex.

[0026] Preferably, the inhibitor comprises any one or a combination of at least two of the following: alkynyl alcohols, polyvinylcyclosiloxanes, alkynyl-modified organosilicon compounds, or fumarate compounds.

[0027] Preferably, the coupling agent comprises a silane coupling agent, and more preferably any one or a combination of at least two of 3-glycidyl etheroxypropyltrimethoxysilane, 3-glycidyl etheroxypropyltriethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltriethoxysilane or 3-methacryloyloxypropylmethyldimethoxysilane.

[0028] This invention overcomes the structural limitations of traditional short-fiber disordered filling and hard powder doping. It employs a continuous, powder-free, long-fiber oriented arrangement structure, combined with a silicone oil-mixed elastic matrix, to construct an intelligent, reversible thermally conductive structure that can slide under stress, reset under stress, and maintain uninterrupted thermal conductivity. This structurally solves the core problems of traditional gaskets, such as high insertion and removal resistance, easy deformation, and thermal resistance drift. Specifically:

[0029] (1) Free state: The carbon fiber long fibers in the thermal pad of the present invention are arranged vertically at 90°, which can construct a complete and continuous vertical thermal conduction channel. It is dense, continuous and without breaks, ensuring ultra-high thermal conductivity, thermal conductivity ≥20 W / (m·K), and extremely low basic thermal resistance.

[0030] (2) Optical module insertion, squeezing and sliding state: When the optical module is pushed in, the heat-conducting pad is subjected to the combined action of lateral shear force and positive pressure. The ultra-soft silicone oil matrix allows the carbon fiber long fiber array to slide flexibly as a whole. The fiber angle is adaptively tilted to 30-45°. The structure conforms to the insertion and removal displacement, greatly reducing the insertion resistance and clamping stress. The clamping stress of the whole machine is ≤5 psi, which will not squeeze the optical module shell and protect the optical module shell from deformation.

[0031] (3) Working fit state: The tilted long fibers still maintain a densely overlapping thermal conductive network, the interface fit is greatly improved, and the steady-state thermal resistance is ≤0.14 cm. 2 • K / W, excellent heat dissipation performance;

[0032] (4) Optical module unloading state: Relying on the ultra-high resilience of the dual silicone oil elastic matrix, after the external force is unloaded, the silicone oil cross-linked elastic network rebounds instantly, driving the carbon fiber long fiber to recover to the initial 90° vertical state without hysteresis or residual deformation, achieving complete self-reset of the structure, with no permanent deformation of the structure, and the rebound rate can reach 100%, allowing for unlimited cycles of insertion and removal.

[0033] In other words, the carbon fiber long-fiber thermal conductive pad provided by this invention, without the need for high-hardness ceramic powder filling, possesses the advantages of being ultra-soft, low-stress, and highly resilient. Specifically: thermal conductivity ≥20 W / (m·K), Shore 00 hardness ≤20, resilience reaching 100% with no permanent deformation, compressive stress ≤5 psi, and steady-state contact thermal resistance ≤0.14 cm. 2 The K / W type tilts at 30-45° when the optical module is inserted and immediately returns to a 90° vertical position after being removed. It is suitable for applications such as high-speed optical module frequent insertion and removal heat dissipation and low-stress precision bonding heat dissipation.

[0034] In a second aspect, the present invention provides a method for preparing a carbon fiber long-fiber thermal conductive pad as described in the first aspect, the method comprising:

[0035] The carbon fiber long fibers arranged in the same direction are surface treated with a coupling agent;

[0036] The slurry is prepared by mixing the formulated amounts of methyl vinyl silicone oil, vinyl silicone oil, dimethyl silicone oil, hydrogen-containing silicone oil, catalyst, and inhibitor.

[0037] The surface-treated, co-oriented carbon fiber long fibers are impregnated with slurry, cured, and then cut perpendicular to the direction of the carbon fiber long fibers to obtain a carbon fiber long fiber thermal conductive pad.

[0038] Preferably, the method for impregnating the slurry includes: impregnating under negative pressure, and performing vacuum treatment after impregnation.

[0039] Preferably, the curing method includes gradient temperature curing, specifically including holding at 40-60℃ (e.g., 40℃, 45℃, 50℃, 55℃, 60℃, etc., but not limited to the listed values; other unlisted values ​​or ranges within the range are also applicable) for 30-60 min (e.g., 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, etc., but not limited to the listed values; other unlisted values ​​or ranges within the range are also applicable), then raising the temperature to 80-100℃ (e.g., 80℃, 85℃, 90℃, 95℃, 100℃, etc., but not limited to the listed values; other unlisted values ​​or ranges within the range are also applicable) and holding at that temperature for 30-60 min (e.g., 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, etc., but not limited to the listed values; other unlisted values ​​or ranges within the range are also applicable) ...). (e.g., min, but not limited to the listed values; other unlisted point values ​​or range values ​​within the value range also apply). Finally, raise the temperature to 120-150℃ (e.g., 120℃, 130℃, 140℃, 145℃, 150℃, etc., but not limited to the listed values; other unlisted point values ​​or range values ​​within the value range also apply) and hold at that temperature for 30-60 min (e.g., 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, etc., but not limited to the listed values; other unlisted point values ​​or range values ​​within the value range also apply).

[0040] As a preferred embodiment of the present invention, the preparation method includes:

[0041] S1. Take continuous, unbroken carbon fiber long fibers and perform regularization treatment through combing, straightening, and arranging to ensure that the fibers are arranged in parallel, without entanglement, misalignment, or breakage. The co-oriented carbon fiber long fibers are then impregnated with a coupling agent to improve the interfacial compatibility and bonding strength between the carbon fiber long fibers and the dual silicone oil matrix, preventing problems such as fiber delamination, slippage, detachment, and peeling failure during long-term insertion and removal. Preferably, the coupling agent is used in solution form, with a concentration of 10-20 wt% (e.g., 10 wt%, 12 wt%, 15 wt%, 18 wt%, 20 wt%, etc., but not limited to the listed values; other unlisted point values ​​or ranges within the numerical range are also applicable). The solvent used includes any one or a combination of at least two of anhydrous ethanol, isopropanol, ethyl acetate, toluene, or xylene.

[0042] S2. According to the weight parts, mix methyl vinyl silicone oil, vinyl silicone oil and dimethyl silicone oil at room temperature at 100-300 rpm (e.g. 100 rpm, 150 rpm, 200 rpm, 250 rpm, 300 rpm, etc., but not limited to the listed values, other unlisted point values ​​or range values ​​within the value range are also applicable) for 15 minutes to make the silicone oil system completely blended and compatible, forming a low modulus, ultra-soft, high toughness and high resilience composite elastic matrix. Then add the formulated amount of hydrogen-containing silicone oil, vulcanization inhibitor and platinum vulcanization catalyst, stir gently until uniform and free of bubbles, seal and store for later use to avoid premature cross-linking and curing.

[0043] S3. The straightened vertical carbon fiber bundles are completely immersed in the three-silicone oil composite matrix and placed in a vacuum degassing device for negative pressure impregnation treatment to remove the air between the fibers and inside the matrix. Then, the composite preform is placed flat into the mold and vacuumed again for 20 minutes to further remove the air between the fibers and inside the matrix, ensuring that the silicone oil matrix completely penetrates the fiber gaps, realizing the fiber-matrix integrated void-free composite, and eliminating the problems of increased thermal resistance and uneven performance caused by pore defects. Then the mold is sealed.

[0044] S4. A segmented gradient low-temperature vulcanization process is adopted to complete the matrix cross-linking reaction in stages. The process involves holding the temperature at 40-60℃ for 30-60 min, raising the temperature to 80-100℃ and holding it for 30-60 min, and finally raising the temperature to 120-150℃ and holding it for 30-60 min. This slow vulcanization and cross-linking process effectively eliminates internal stress in the matrix, fully preserves the extreme flexibility and resilience of the silicone oil system, and eliminates defects such as gasket hardening, increased brittleness, and decreased resilience caused by traditional high-temperature vulcanization.

[0045] S5. After vulcanization, the material is naturally cooled to room temperature to ensure structural dimensional stability and no deformation. Then, it is cut and polished to obtain an ultra-soft, ultra-low stress, high resilience, and self-resetting carbon fiber long-fiber thermal conductive pad.

[0046] Thirdly, the present invention provides an application of the carbon fiber long-fiber thermal conductive pad as described in the first aspect in the field of heat dissipation for optical module plug-in, preferably in the fields of heat dissipation for 5G / 6G communication optical modules, high-speed switches, data center optical transceiver modules, and high-frequency optoelectronic modules.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] (1) Ultra-low stress non-destructive insertion and removal, suitable for high-frequency operation and maintenance: This invention adopts a dual soft matrix system with elastic cross-linking of dimethyl silicone oil, low viscosity vinyl silicone oil and methyl vinyl silicone oil, and eliminates hard powder filling. The finished product has a Shore 00 hardness of only 10, clamping stress ≤ 5 psi, and extremely low insertion and removal friction resistance. It avoids the problems of shell extrusion deformation, gold finger damage and cavity displacement during optical module insertion and removal from the root, and is fully suitable for high-frequency disassembly and assembly operation and maintenance scenarios in data centers.

[0049] (2) High thermal conductivity and ultra-low thermal resistance, with excellent heat dissipation performance: This invention uses continuous long carbon fiber to construct a fully continuous vertical heat conduction path, eliminating thermal islands and powder interface contact thermal resistance. The heat conduction path is continuous and stable, with the finished product having a thermal conductivity ≥20 W / (m·K) and a steady-state operating thermal resistance ≤0.14 cm. 2 • K / W, which can quickly dissipate the high-density heat of the 800 G / 1.6 T high-speed optical module, meeting the heat dissipation requirements of ultra-high power consumption devices;

[0050] (3) 100% elastic recovery, no permanent deformation: The dual silicone oil composite cross-linked network has excellent flexibility and elastic recovery ability. There is no structural damage during the insertion and removal of the gasket under force. After the external force is unloaded, it can be completely restored without hysteresis and residual deformation. The rebound rate is 100%. After tens of thousands of insertion and removal cycles, there is no collapse, no relaxation, and no thermal resistance drift. The long-term working reliability is extremely high.

[0051] (4) Adaptive and reversible structure with strong adaptability to working conditions: This invention provides an adaptive heat conduction structure for optical modules. When inserted, the carbon fiber long fiber is tilted at 30-45° to achieve sliding and drag reduction, reducing assembly difficulty. It maintains a stable heat conduction path during operation to ensure heat dissipation efficiency. When pulled out, it automatically resets to a 90° vertical structure to achieve reversible switching of functions, perfectly adapting to the optical module insertion and removal alternating working mode.

[0052] (5) Ultra-soft bonding and high heat dissipation stability: The ultra-low Shore 00 hardness (Shore 00=10) has excellent flexible bonding performance, which can adaptively fill the tiny gaps in the heat dissipation surface of the optical module, completely eliminate the interface air insulation layer, stably maintain ultra-low contact thermal resistance, and ensure long-term constant temperature stable operation of the equipment. Detailed Implementation

[0053] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below.

[0054] It should be noted that the specific embodiments listed below are merely descriptions of the principles and features of the present invention, and the examples are only used to explain the present invention and are not intended to limit the scope of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0055] For example, in this invention, the coupling agent includes any one or a combination of at least two of 3-glycidyl etheroxypropyltrimethoxysilane, 3-glycidyl etheroxypropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, or 3-methacryloxypropylmethyldimethoxysilane. This invention only uses KBM-403 and KBM-503 as examples and does not mean that only KBM-403 and KBM-503 can be used. In this invention, KBM-403 and KBM-503 can also be replaced by combinations of 3-glycidyl etheroxypropyltriethoxysilane, γ-methacryloxypropyltriethoxysilane, or 3-methacryloxypropylmethyldimethoxysilane. Other structures and raw materials of this invention can be understood in the same way.

[0056] Unless otherwise specified, in this invention, the terms "first," "second," etc., are used to distinguish different objects, rather than to describe a specific order or primary / secondary relationship.

[0057] Unless otherwise stated, the terminology used in this invention has the common meaning as generally understood by those skilled in the art.

[0058] Unless otherwise stated, the values ​​of the parameters mentioned in this invention can be determined using various testing methods commonly used in the art, for example, according to the testing methods given in the embodiments of this invention. Unless otherwise stated, the test temperature for each parameter is 25°C.

[0059] Unless otherwise specified, the raw materials involved in the following specific embodiments of the present invention are all conventional materials in the art, and can be purchased from commercially available products. Some raw material information is as follows:

[0060] Methyl vinyl silicone rubber-1: Mooney viscosity ML (1+4) 40-70 Mooney at 100℃, vinyl content 0.13-0.18 wt%, purchased from Dongjue Organosilicon Group Co., Ltd., grade 110-2;

[0061] Methyl vinyl silicone rubber-2: Mooney viscosity ML (1+4) 40-70 Mooney at 100℃, vinyl content 0.19-0.24 wt%, purchased from Dongjue Organosilicon Group Co., Ltd., grade 110-3;

[0062] Methyl vinyl silicone rubber-3: Mooney viscosity ML (1+4) 40-70 Mooney at 100℃, vinyl content 1.8-5.0 wt%, purchased from Dongjue Organosilicon Group Co., Ltd., grade 110-7;

[0063] Vinyl silicone oil-1: with a viscosity of 100 mPa·s at 25℃ and a vinyl content of 1.9 wt%, purchased from Guangdong Chenxi New Material Technology Co., Ltd., grade CX-352-100;

[0064] Vinyl silicone oil-2: viscosity at 25℃ is 200 mPa·s, vinyl content is 1.1 wt%, purchased from Guangdong Chenxi New Material Technology Co., Ltd., grade CX-352-200;

[0065] Vinyl silicone oil-3: viscosity at 25℃ is 10000 mPa·s, vinyl content is 0.3 wt%, purchased from Guangdong Chenxi New Material Technology Co., Ltd., grade CX-352-10000;

[0066] Dimethyl silicone oil-1: The viscosity at 25℃ is 100 mPa·s, purchased from Dow Corning, brand name PMX-200-100;

[0067] Dimethyl silicone oil-2: viscosity at 25℃ is 200 mPa·s, purchased from Dow Corning, grade PMX-200-200;

[0068] Dimethyl silicone oil-3: viscosity at 25℃ is 1000 mPa·s, purchased from Dow Corning, grade PMX-200-1000;

[0069] Hydrogen-containing silicone oil-1: The viscosity at 25℃ is 25 mPa·s, and the hydrogen content is 0.36 wt%. It was purchased from Dow Chemical Company, and the brand name is MHX-0036.

[0070] Hydrogen-containing silicone oil-2: viscosity at 25℃ is 20 mPa·s, hydrogen content is 0.4 wt%, purchased from Shin-Etsu Chemical Industry Co., Ltd., brand name KF-99-LH;

[0071] Carbon fiber long fiber-1: purchased from Hunan Dongying Carbon Materials, grade TYG-2;

[0072] Carbon fiber long fiber-2: purchased from Hunan Dongying Carbon Materials, grade TYG-3;

[0073] Platinum catalyst: purchased from Shin-Etsu Chemical Industry Co., Ltd., brand name CAT-PL-56;

[0074] Inhibitor: Purchased from Shin-Etsu Chemical Industry Co., Ltd., brand name INH-S;

[0075] Coupling agent-1: purchased from Shin-Etsu Chemical Industry Co., Ltd., brand name KBM-403;

[0076] Coupling agent-2: purchased from Shin-Etsu Chemical Industry Co., Ltd., brand name KBM-503;

[0077] Examples and Comparative Examples

[0078] This embodiment provides a carbon fiber long-fiber thermal conductive pad, the specific composition of which is shown in Table 1-2:

[0079] Table 1

[0080]

[0081] Table 2

[0082]

[0083] The preparation method is as follows:

[0084] S1. Take continuous, unbroken carbon fiber long fibers and perform regularization treatment through combing, straightening, and arranging to ensure that the fibers are arranged in parallel, without entanglement, misalignment, or breakage. Soak the carbon fiber long fibers arranged in the same direction in a 16 wt% coupling agent solution (solvent is anhydrous ethanol) at room temperature for 30 min.

[0085] S2. According to the weight parts, methyl vinyl silicone oil, vinyl silicone oil and dimethyl silicone oil are stirred at 200 rpm for 15 min at room temperature and mixed evenly. Then add the formulated amount of hydrogen-containing silicone oil, sulfurization inhibitor and platinum sulfurization catalyst and mix evenly. Seal and set aside for later use.

[0086] S3. The straightened vertical carbon fiber bundles are completely immersed in the three silicone oil composite matrix and placed in a vacuum degassing device for negative pressure (0.9 MPa) impregnation treatment. Then, the composite blank is placed flat into the mold and treated with a vacuum pump for a second vacuum (0.9 MPa) for 20 min, and then the mold is sealed.

[0087] S4. Hold at 60℃ for 30 min, raise the temperature to 90℃ and hold for 30 min, and finally raise the temperature to 120℃ and hold for 30 min to slowly complete the vulcanization crosslinking.

[0088] S5. After vulcanization, allow the material to cool naturally to room temperature, then cut and polish to obtain carbon fiber long-fiber thermal conductive pads.

[0089] Comparative Example 10

[0090] This comparative example provides a conventional commercial thermal pad (purchased from Laird, brand name Laird Tflex SF10).

[0091] Performance testing

[0092] The performance of the samples provided in the examples and comparative examples was tested using the following methods:

[0093] (1) Thermal conductivity: The thermal conductivity was tested using a Ruiling thermal conductivity tester, in accordance with ASTM D5470 "Standard Test Method for Thermal Conductivity of Thin Thermally Conductive Solid Electrical Insulators";

[0094] (2) Shore 00: The Shore 00 hardness tester was used and the test was conducted in accordance with ASTM D2240 "Standard Test Methods for Rubber Properties - Hardness Tester".

[0095] (3) Compression stress: The test was conducted using an Instron universal testing machine, in accordance with ASTM D575-91(2012) "Standard Test Method for Compression Properties of Rubber";

[0096] (4) Steady-state thermal resistance: The test was conducted using a Ruixing thermal tester, referring to ASTM D5470 "Standard Test Method for Thermal Conductivity of Thin Thermally Conductive Solid Electrical Insulators";

[0097] (5) Insertion and removal test: Insertion and removal test is performed with a test pressure of 5 psi;

[0098] The test results are as follows:

[0099] Table 3

[0100]

[0101] As demonstrated by the embodiments and performance tests, the carbon fiber long-fiber thermal conductive pad provided by this invention possesses excellent thermal conductivity, while also exhibiting the advantages of being ultra-soft, low-stress, and highly resilient. Specifically: thermal conductivity ≥20 W / (m·K), Shore 00 hardness ≤10, resilience reaching 100% with no permanent deformation, compressive stress ≤5 psi, and steady-state contact thermal resistance ≤0.14 cm. 2• K / W, which tilts 30-45° when the optical module is inserted, and immediately resets to 90° vertical after being pulled out, without permanent deformation.

[0102] As can be seen from the comparison between Examples 1-6 and Comparative Examples 1-3, the preferred combination of methyl vinyl silicone oil, vinyl silicone oil and dimethyl silicone oil in this invention, combined with carbon fiber long fibers, enables the resulting carbon fiber long fiber thermal conductive pad to have the advantages of being ultra-soft, low-stress and highly resilient.

[0103] As can be seen from the comparison of Example 1 and Comparative Examples 1-10, the weight proportions of methyl vinyl silicone oil, vinyl silicone oil and dimethyl silicone oil need to be within the limits of this invention, and all three are indispensable. Only when combined with carbon fiber long fibers can a thermally conductive pad that meets the performance requirements be obtained.

[0104] The present invention has been illustrated through the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A carbon fiber long-fiber thermal conductive pad, characterized in that, By weight, the raw materials include 8-10 parts of methyl vinyl silicone rubber, 20-25 parts of vinyl silicone oil, 10-12 parts of dimethyl silicone oil, 2-4 parts of hydrogen-containing silicone oil, 55-60 parts of carbon fiber long fibers, 1-2 parts of catalyst, 0.05-0.1 parts of inhibitor and 0.5-1.0 parts of coupling agent.

2. The carbon fiber long-fiber thermal conductive pad according to claim 1, characterized in that, In the thermally conductive pad, the long carbon fiber fibers are arranged vertically in the Z-direction.

3. The carbon fiber long-fiber thermal conductive pad according to claim 1 or 2, characterized in that, The Shore 00 of the carbon fiber thermal conductive pad is ≤10. And / or, the compressive holding stress of the carbon fiber thermal pad is ≤5 psi; And / or, the resilience of the carbon fiber thermal pad is ≥99.9%.

4. The carbon fiber long-fiber thermally conductive pad according to any one of claims 1-3, characterized in that, The methyl vinyl silicone rubber has a Mooney viscosity of 40-70 and a vinyl content of 0.1-0.5 wt%. And / or, the viscosity of the vinyl silicone oil is 100-200 mPa·s, and the vinyl content is 1-3 wt%; And / or, the viscosity of the dimethyl silicone oil is 100-200 mPa·s.

5. The carbon fiber long-fiber thermally conductive pad according to any one of claims 1-4, characterized in that, The hydrogen-containing silicone oil has a viscosity of 20-40 mPa·s and a hydrogen content of 0.1-0.5 wt%.

6. The carbon fiber long-fiber thermally conductive pad according to any one of claims 1-5, characterized in that, The catalyst includes a platinum-based catalyst, preferably including any one or a combination of at least two of the following: isopropanol chloroplatinate complex, platinum-1,3-divinyltetramethyldisiloxane complex, or platinum cycloolefin complex. And / or, the inhibitors include any one or a combination of at least two of the following: alkynyl alcohols, polyvinylcyclosiloxanes, alkynyl-modified organosilicon compounds, or fumarate compounds; And / or, the coupling agent comprises a silane coupling agent, preferably any one or a combination of at least two of 3-glycidyl etheroxypropyltrimethoxysilane, 3-glycidyl etheroxypropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane or 3-methacryloxypropylmethyldimethoxysilane.

7. A method for preparing a carbon fiber long-fiber thermally conductive pad as described in any one of claims 1-6, characterized in that, The preparation method includes: The carbon fiber long fibers arranged in the same direction are surface treated with a coupling agent; The slurry is prepared by mixing the formulated amounts of methyl vinyl silicone oil, vinyl silicone oil, dimethyl silicone oil, hydrogen-containing silicone oil, catalyst, and inhibitor. The surface-treated, co-oriented carbon fiber long fibers are impregnated with slurry, cured, and then cut perpendicular to the direction of the carbon fiber long fibers to obtain a carbon fiber long fiber thermal conductive pad.

8. The preparation method according to claim 7, characterized in that, The method for impregnating the slurry includes: impregnating under negative pressure, and performing vacuum treatment after impregnation.

9. The preparation method according to claim 7 or 8, characterized in that, The curing method includes gradient temperature curing, preferably including holding at 40-60℃ for 30-60 min, raising the temperature to 80-100℃ and holding for 30-60 min, and finally raising the temperature to 120-150℃ and holding for 30-60 min.

10. The application of a carbon fiber long-fiber thermally conductive pad as described in any one of claims 1-6 in the field of heat dissipation for optical module plug-in, preferably in the fields of heat dissipation for 5G / 6G communication optical modules, high-speed switches, data center optical transceiver modules, and high-frequency optoelectronic modules.

Images