Non-silicon heat-conducting gasket and preparation method thereof

Abstract

The invention relates to the field of heat-conducting materials, in particular to a non-silicon heat-conducting gasket and a preparation method thereof. The non-silicon heat-conducting gasket is prepared from the following raw materials in parts by mass: 5 to 10 parts of a non-silicon polymer, 180 to 200 parts of heat-conducting filler, 0.3 to 0.5 part of a treating agent, 0.3 to 0.5 part of an antioxidant, 0.4 to 1 part of a cross-linking agent and 0.03 to 0.2 part of a catalyst, wherein the non-silicon polymer comprises polyester polyol, and the heat-conducting filler comprises aluminum nitride and aluminum oxide. The heat conductivity coefficient of the prepared non-silicon heat-conducting gasket can reach 10 W / m.K or above, the hardness is not smaller than 50 shore 00, and the non-silicon heat-conducting gasket has an excellent heat-conducting effect.

Description

Technical Field

[0001] The invention relates to the field of heat-conducting materials, and in particular to a non-silicon heat-conducting gasket and a preparation method thereof. Background Art

[0002] With the rapid development of electronic information technology, the trend of miniaturization of electronic technology products is becoming increasingly obvious. However, miniaturization also brings new problems, that is, the heat generated by electronic products during work is difficult to dissipate effectively, which in turn causes damage to the body, accelerates device aging, shortens service life, and even causes malfunction. Therefore, how to quickly conduct and dissipate heat has become a key technical problem that current electronic products need to solve urgently. In the field of thermal conductive materials, thermal conductive gaskets have attracted widespread attention for their excellent performance; thermal conductive gaskets are mainly made of silicone oil as the main raw material, and are added with fillers such as metal oxides and processed by special processes. It has the characteristics of low thermal resistance, high thermal conductivity, good insulation, and strong sealing. It can transfer heat between the heating part and the heat dissipation part through the tiny gap on the gasket, thereby effectively realizing the rapid dissipation of heat. However, the silicone oil component in the thermal conductive gasket may overflow under high temperature environment. Especially in electronic products, the volatilization of small siloxane molecules in silicone oil will be adsorbed on the interface surface, which will indirectly affect the performance of the body. Therefore, it is particularly important to find a new thermal conductive material that does not have the problem of silicone oil overflow. Non-silicon thermal conductive gaskets came into being in this context. Compared with thermal conductive gaskets, the biggest feature of non-silicone thermal conductive gaskets is that the raw materials do not include silicone oil, so it can effectively avoid the problems caused by silicone oil overflow, allowing the product to work and operate more stably in a high temperature environment.

[0003] Prior art CN118185325A discloses a high-performance non-silicone thermal conductive ester and a preparation method thereof. The preparation raw materials mainly include non-silicone oil, thermal conductive composite filler, treatment agent and antioxidant; the thermal conductivity coefficient of the product can reach above 5.2W / m·K, but the thermal conductivity performance still has obvious room for improvement.

[0004] Therefore, how to prepare a non-silicon thermal conductive gasket with high thermal conductivity and high hardness is an industry-wide technical issue that is currently being focused on in this field. Summary of the invention

[0005] In order to solve the above technical problems, the first aspect of the present invention provides a non-silicon thermally conductive gasket, the raw materials for preparing the non-silicon thermally conductive gasket include: non-silicon polymer, thermally conductive filler, treatment agent, antioxidant, cross-linking agent, and catalyst.

[0006] As an implementable case, the raw materials for preparing the non-silicon thermal conductive gasket include, by weight: 5-10 parts of non-silicon polymer, 180-200 parts of thermal conductive filler, 0.3-0.5 parts of treatment agent, 0.3-0.5 parts of antioxidant, 0.4-1 parts of cross-linking agent, and 0.03-0.2 parts of catalyst.

[0007] Furthermore, the raw materials for preparing the non-silicon thermally conductive gasket include, by weight: 6.2 parts of non-silicon polymer, 192 parts of thermally conductive filler, 0.4 parts of treating agent, 0.4 parts of antioxidant, 0.9 parts of cross-linking agent, and 0.1 parts of catalyst.

[0008] As an implementable case, the non-silicone polymer includes: one or more of polyester polyol, polyether polyol, polyurethane resin, acrylate resin, polystyrene resin, and epoxy resin.

[0009] Furthermore, the non-silicone polymer is polyester polyol, and the brand of polyester polyol may include PH-100D, which is purchased from Ito Oil Manufacturing Co., Ltd.

[0010] In order to solve the technical defect of the existing silicone oil system thermal conductive materials that silicone oil is easy to overflow at high temperature and cause product damage, the present invention preferably uses non-silicone polymer polyester polyol as the preparation raw material, which can be cross-linked and cured under the action of catalyst and cross-linking agent, which not only improves the firmness between the thermal conductive filler particles, but also can further improve the mechanical properties of the non-silicone thermal conductive gasket, so that its application range is wider.

[0011] As an implementable case, the thermally conductive filler includes one or more of carbon nanotubes, aluminum oxide, zinc oxide, boron nitride, aluminum nitride, aluminum powder, graphene, silicon carbide, and quartz powder.

[0012] Furthermore, the thermally conductive filler includes: aluminum nitride and aluminum oxide.

[0013] Furthermore, the mass ratio of aluminum nitride to aluminum oxide is (100-115):(80-100).

[0014] Furthermore, the mass ratio of aluminum nitride to aluminum oxide is 102:90.

[0015] As an implementable case, the aluminum nitride includes one or more of spherical aluminum nitride, quasi-spherical aluminum nitride, single-crystal aluminum nitride, polycrystalline aluminum nitride, and quasi-single-crystal aluminum nitride.

[0016] As an implementable case, the particle size of the aluminum nitride is 80-100 μm, including one or more of 80 μm, 90 μm, and 100 μm.

[0017] Furthermore, the aluminum nitride includes spherical aluminum nitride with a particle size of 80 μm.

[0018] As an implementable case, the alumina includes one or more of spherical alumina, quasi-spherical alumina, single-crystal alumina, polycrystalline alumina, and quasi-single-crystal alumina.

[0019] As an implementable case, the particle size of the aluminum oxide is 0.5-40 μm, including one or more of 0.5 μm, 0.8 μm, 1 μm, 3 μm, 5 μm, 10 μm, 20 μm, and 40 μm.

[0020] Furthermore, the alumina includes spherical alumina and single crystal alumina.

[0021] Furthermore, the mass ratio of the single crystal alumina to the spherical alumina is (3-5):1.

[0022] Furthermore, the particle size of the single crystal alumina is 0.5-1 μm, and the particle size of the spherical alumina is 10-40 μm.

[0023] Furthermore, the alumina includes: spherical alumina with a particle size of 40 μm, spherical alumina with a particle size of 10 μm and single crystal alumina with a particle size of 0.5 μm.

[0024] Furthermore, the mass ratio of the spherical alumina with a particle size of 40 μm, the spherical alumina with a particle size of 10 μm and the single crystal alumina with a particle size of 0.5 μm is 40:30:20.

[0025] Spherical alumina with a particle size of 40μm, as a larger particle, can form a "skeleton" in the thermal conductive filler and provide the main thermal conduction path; spherical alumina with a particle size of 10μm has a moderate particle size and can fill the gaps between 40μm particles, further increasing the continuity of the thermal conduction channel; and 0.5μm single-crystalline alumina, as the smallest particle, can penetrate into the tiny gaps between larger particles to form a tight stacking, reduce thermal resistance, and provide higher thermal conductivity through the single crystal structure; in addition, due to the more ordered internal lattice structure, single-crystalline alumina is superior to polycrystalline alumina in thermal conductivity, reducing thermal scattering and heat accumulation at the grain boundaries. 0.5μm single-crystalline alumina can serve as an efficient thermal conduction "bridge" to connect larger alumina particles to form a more efficient thermal conduction network. By compounding three types of alumina with different particle sizes, a thermal conductive filler system with a wide particle size distribution can be obtained, which is conducive to forming a compact stack and a continuous thermal conductive channel, thereby improving the overall thermal conductivity of the non-silicon thermal conductive gasket; and aluminum nitride is a material with a high thermal conductivity coefficient, and its theoretical thermal conductivity coefficient can reach 600W / m·K, which is much higher than that of aluminum oxide. In the present invention, large-particle spherical aluminum nitride with a particle size of 80μm is added to the thermal conductive filler in the system, which can further improve the thermal conductivity and hardness of the non-silicon thermal conductive gasket, so that the thermal conductivity of the product can reach more than 10W / m·K, and the hardness is not less than 50shore 00.

[0026] As an implementable case, the treatment agent includes: one or more of a coupling agent, a dispersant, a plasticizer, and a water absorbent.

[0027] Furthermore, the treating agent is a coupling agent.

[0028] As an implementable case, the coupling agent includes: one or more of octyltrimethoxysilane, dodecyltrimethoxysilane, n-octyltriethoxysilane, vinyltrimethoxysilane, hydroxypolydimethylsiloxane, and glycol-based polydimethylsiloxane.

[0029] Furthermore, the coupling agent is dodecyltrimethoxysilane.

[0030] The coupling agent dodecyltrimethoxysilane itself has a low thermal conductivity, but after being coated on the surface of the thermal conductive filler, it can reduce the thermal resistance of the system by reducing the defects and gaps in the system; at the same time, the coupling agent can also improve the interface compatibility between the thermal conductive filler and the matrix material, making the heat transfer process smoother. Therefore, the addition of the coupling agent can significantly improve the thermal conductivity of the thermal conductive material; in addition, dodecyltrimethoxysilane can also enhance the interaction and compatibility between the raw materials of each component, so that a tighter stacking and continuous thermal conductive channel are formed inside the non-silicon thermal conductive gasket, further reducing the thermal resistance of the product and improving the thermal conductivity.

[0031] The present invention does not further limit the selection of antioxidants, and any component that can play an antioxidant and anti-aging role can be used, including but not limited to: one or more of antioxidant 1010, antioxidant 168, antioxidant 1076, antioxidant 264, antioxidant 2246, antioxidant 330, and antioxidant DNP.

[0032] As an implementable case, the cross-linking agent includes: one of MDI, TDI, HDI, hydrogenated MDI, hydrogenated TDI, and hydrogenated HDI.

[0033] Furthermore, the crosslinking agent is hydrogenated MDI (4,4′-diisocyanate dicyclohexylmethane).

[0034] The isocyanate group of hydrogenated MDI has high reactivity and can undergo nucleophilic addition reaction with the hydroxyl group in polyester polyol to form a polyurethane component with high cross-linking density, which is beneficial to improve the hardness of the non-silicone thermal conductive gasket.

[0035] As an implementable case, the catalyst includes: at least one of dibutyltin dilaurate, dibutyltin dioctoate, N,N-dimethylethanolamine, stannous octoate, dibutyltin diacetate, di(dodecylsulfide)dibutyltin, N-methylmorpholine, N-ethylmorpholine, N-methylimidazole, triethanolamine, and triethylamine.

[0036] Furthermore, the catalyst is dibutyltin dioctoate.

[0037] A second aspect of the present invention provides a method for preparing a non-silicon thermally conductive pad, comprising:

[0038] S1. Mix the antioxidant and non-silicon polymer, the treatment agent and the thermal conductive filler, and stir at 60-80°C for 30-60 minutes;

[0039] S2, add cross-linking agent and catalyst, raise the temperature to 110-130°C, and stir under vacuum for 30-60 minutes;

[0040] S3, discharging and calendering, and the product is obtained.

[0041] Beneficial Effects

[0042] (i) In the present invention, non-silicone polymer polyester polyol is selected as the main raw material for preparation instead of silicone oil, so that the non-silicone thermal conductive gasket of the product will not leak oil in a high temperature environment.

[0043] (ii) The present invention selects hydrogenated MDI as a cross-linking agent and mixes it with polyester polyol, which can further improve the hardness of the product and its adhesion performance on electronic products.

[0044] (III) The present invention selects spherical alumina with a particle size of 40 μm, spherical alumina with a particle size of 10 μm and single crystal alumina with a particle size of 0.5 μm to form a compact stack and a continuous heat conduction channel, thereby improving the overall thermal conductivity of the non-silicon thermal conductive pad.

[0045] (iv) In order to further improve the thermal conductivity and hardness of the product, the present invention adds spherical aluminum nitride with a particle size of 80 μm to the thermal conductive filler system, which can make the thermal conductivity of the product reach above 10 W / m·K and the hardness not less than 50 shore00.

[0046] (V) The present invention performs a heating and vacuuming operation during the preparation of the non-silicon thermally conductive gasket, which can effectively reduce the content of impurities such as water and air in the product, thereby improving the aging resistance and thermal conductivity of the non-silicon thermally conductive gasket. DETAILED DESCRIPTION

[0047] Example 1

[0048] The first aspect of this example provides a non-silicon thermally conductive gasket, the raw materials for its preparation, calculated by weight, include: 6.2 parts of non-silicon polymer, 192 parts of thermally conductive filler, 0.4 parts of treating agent, 0.4 parts of antioxidant, 0.9 parts of cross-linking agent, and 0.1 parts of catalyst.

[0049] The non-silicon polymer is polyester polyol, with the brand name PH-100D, purchased from Ito Oil Manufacturing Co., Ltd.

[0050] The thermal conductive filler is calculated by weight as follows: 102 parts of spherical aluminum nitride with a particle size of 80 μm, 40 parts of spherical aluminum oxide with a particle size of 40 μm, 30 parts of spherical aluminum oxide with a particle size of 10 μm, and 20 parts of single crystal aluminum oxide with a particle size of 0.5 μm, all of which are common commercially available products.

[0051] The treating agent is dodecyltrimethoxysilane.

[0052] The antioxidant is antioxidant 1010, a common commercial product.

[0053] The cross-linking agent is hydrogenated MDI.

[0054] The catalyst is dibutyltin dioctoate.

[0055] A second aspect of this example provides a method for preparing a non-silicon thermally conductive gasket, comprising:

[0056] S1. Mix the antioxidant and non-silicon polymer, the treatment agent and the thermal conductive filler, and stir at 65°C for 30 minutes;

[0057] S2, add cross-linking agent and catalyst, raise the temperature to 120°C, and stir under vacuum for 30 minutes;

[0058] S3, discharge the material and roll it into a non-silicon thermal conductive pad with a thickness of 2 mm.

[0059] Example 2

[0060] The first aspect of this example provides a non-silicon thermally conductive gasket, the raw materials for its preparation, calculated by weight, include: 5 parts of non-silicon polymer, 193 parts of thermally conductive filler, 0.5 parts of treating agent, 0.5 parts of antioxidant, 0.4 parts of cross-linking agent, and 0.03 parts of catalyst.

[0061] The non-silicon polymer is polyester polyol, with the brand name PH-100D, purchased from Ito Oil Manufacturing Co., Ltd.

[0062] The thermal conductive filler is calculated by weight as follows: 60 parts of spherical aluminum nitride with a particle size of 120 μm, 50 parts of spherical aluminum oxide with a particle size of 70 μm, 46 parts of spherical aluminum oxide with a particle size of 10 μm, and 37 parts of single crystal aluminum oxide with a particle size of 0.5 μm, all of which are common commercially available products.

[0063] The treating agent is dodecyltrimethoxysilane.

[0064] The antioxidant is antioxidant 1010, a common commercial product.

[0065] The cross-linking agent is hydrogenated MDI.

[0066] The catalyst is dibutyltin dioctoate.

[0067] A second aspect of this example provides a method for preparing a non-silicon thermally conductive gasket, comprising:

[0068] S1. Mix the antioxidant and non-silicon polymer, the treatment agent and the thermal conductive filler, and stir at 65°C for 30 minutes;

[0069] S2, add cross-linking agent and catalyst, raise the temperature to 120°C, and stir under vacuum for 30 minutes;

[0070] S3, discharge the material and roll it into a non-silicon thermal conductive pad with a thickness of 2 mm.

[0071] Example 3

[0072] The first aspect of this example provides a non-silicon thermally conductive gasket, the raw materials for its preparation, calculated by weight, include: 10 parts of non-silicon polymer, 184 parts of thermally conductive filler, 0.3 parts of treating agent, 0.3 parts of antioxidant, 1 part of cross-linking agent, and 0.2 parts of catalyst.

[0073] The non-silicon polymer is polyester polyol, with the brand name PH-100D, purchased from Ito Oil Manufacturing Co., Ltd.

[0074] The thermal conductive filler is calculated by weight as follows: 57 parts of spherical alumina with a particle size of 120 μm, 50 parts of spherical alumina with a particle size of 90 μm, 40 parts of spherical alumina with a particle size of 10 μm, and 37 parts of single crystal alumina with a particle size of 0.5 μm, all of which are common commercially available products.

[0075] The treating agent is dodecyltrimethoxysilane.

[0076] The antioxidant is antioxidant 1010, a common commercial product.

[0077] The cross-linking agent is hydrogenated MDI.

[0078] The catalyst is dibutyltin dioctoate.

[0079] A second aspect of this example provides a method for preparing a non-silicon thermally conductive gasket, comprising:

[0080] S1. Mix the antioxidant and non-silicon polymer, the treatment agent and the thermal conductive filler, and stir at 65°C for 30 minutes;

[0081] S2, add cross-linking agent and catalyst, raise the temperature to 120°C, and stir under vacuum for 30 minutes;

[0082] S3, discharge the material and roll it into a non-silicon thermal conductive pad with a thickness of 2 mm.

[0083] Example 4

[0084] The first aspect of this example provides a non-silicon thermally conductive gasket, the raw materials for its preparation, calculated by weight, include: 6.05 parts of non-silicon polymer, 193 parts of thermally conductive filler, 0.4 parts of treating agent, 0.4 parts of antioxidant, 0.1 parts of cross-linking agent, and 0.03 parts of catalyst.

[0085] The non-silicon polymer is polyester polyol, with the brand name PH-100D, purchased from Ito Oil Manufacturing Co., Ltd.

[0086] The thermal conductive filler is calculated by weight as follows: 60 parts of spherical alumina with a particle size of 120 μm, 45 parts of spherical alumina with a particle size of 90 μm, 10 parts of spherical alumina with a particle size of 40 μm, 41 parts of quasi-spherical alumina with a particle size of 10 μm, 20 parts of spherical alumina with a particle size of 0.8 μm, and 17 parts of spherical alumina with a particle size of 0.2 μm, all of which are common commercially available products.

[0087] The treating agent is dodecyltrimethoxysilane.

[0088] The antioxidant is antioxidant 1010, a common commercial product.

[0089] The cross-linking agent is hydrogenated MDI.

[0090] The catalyst is dibutyltin dioctoate.

[0091] A second aspect of this example provides a method for preparing a non-silicon thermally conductive gasket, comprising:

[0092] S1. Mix the antioxidant and non-silicon polymer, the treatment agent and the thermal conductive filler, and stir at 65°C for 30 minutes;

[0093] S2, add cross-linking agent and catalyst, raise the temperature to 120°C, and stir under vacuum for 30 minutes;

[0094] S3, discharge the material and roll it into a non-silicon thermal conductive pad with a thickness of 2 mm.

[0095] Example 5

[0096] The first aspect of this example provides a non-silicon thermally conductive gasket, the raw materials for its preparation, calculated by weight, include: 6.07 parts of non-silicon polymer, 193 parts of thermally conductive filler, 0.4 parts of treatment agent, 0.4 parts of antioxidant, 0.1 parts of cross-linking agent, and 0.03 parts of catalyst.

[0097] The non-silicon polymer is polyester polyol, with the brand name PH-100D, purchased from Ito Oil Manufacturing Co., Ltd.

[0098] The thermal conductive filler is calculated by weight as follows: 110 parts of spherical alumina with a particle size of 80 μm, 46 parts of spherical alumina with a particle size of 10 μm, 20 parts of spherical alumina with a particle size of 0.8 μm, and 17 parts of spherical alumina with a particle size of 0.2 μm.

[0099] The treating agent is dodecyltrimethoxysilane.

[0100] The antioxidant is antioxidant 1010, which is a common commercial product.

[0101] The cross-linking agent is hydrogenated MDI.

[0102] The catalyst is dibutyltin dioctoate.

[0103] A second aspect of this example provides a method for preparing a non-silicon thermally conductive gasket, comprising:

[0104] S1. Mix the antioxidant and non-silicon polymer, the treatment agent and the thermal conductive filler, and stir at 65°C for 30 minutes;

[0105] S2, add cross-linking agent and catalyst, raise the temperature to 120°C, and stir under vacuum for 30 minutes;

[0106] S3, discharge the material and roll it into a non-silicon thermal conductive pad with a thickness of 2 mm.

[0107] Performance Evaluation

[0108] Test object: the non-silicon thermally conductive gasket prepared in Examples 1-5.

[0109] Test items: thermal conductivity and hardness.

[0110] The test methods and test results are detailed in Table 1.

[0111] Table 1

[0112]

[0113] It can be seen from the experimental results of the above-mentioned Examples 1 and 4-5 that the thermal conductivity and hardness of the non-silicon thermally conductive gasket can be further improved by selecting spherical aluminum nitride with a particle size of 80 μm, spherical alumina with a particle size of 40 μm, spherical alumina with a particle size of 10 μm and single crystal alumina with a particle size of 0.5 μm as thermal conductive fillers.

Claims

1. A non-silicon thermally conductive pad, characterized in that: The raw materials for preparing the non-silicon thermally conductive gasket include, by weight, 5-10 parts of non-silicon polymer, 180-200 parts of thermally conductive filler, 0.3-0.5 parts of treating agent, 0.3-0.5 parts of antioxidant, 0.4-1 parts of cross-linking agent, and 0.03-0.2 parts of catalyst.

2. The non-silicon thermally conductive pad according to claim 1, characterized in that: The catalyst comprises at least one of dibutyltin dilaurate, dibutyltin dioctoate, N,N-dimethylethanolamine, stannous octoate, dibutyltin diacetate, dibutyltin didodecylsulfide, N-methylmorpholine, N-ethylmorpholine, N-methylimidazole, triethanolamine and triethylamine.

3. The non-silicon thermally conductive pad according to claim 1, characterized in that: The non-silicon polymer includes one or more of polyester polyol, polyether polyol, polyurethane resin, acrylate resin, polystyrene resin and epoxy resin.

4. The non-silicon thermally conductive pad according to claim 1, characterized in that: The thermal conductive filler includes one or more of carbon nanotubes, aluminum oxide, zinc oxide, boron nitride, aluminum nitride, aluminum powder, graphene, silicon carbide, and quartz powder.

5. The non-silicon thermally conductive pad according to claim 4, characterized in that: The thermal conductive filler comprises aluminum nitride and aluminum oxide; the mass ratio of aluminum nitride to aluminum oxide is (100-115):(80-100).

6. The non-silicon thermally conductive pad according to claim 5, characterized in that: The aluminum nitride includes one or more of spherical aluminum nitride, quasi-spherical aluminum nitride, single-crystal aluminum nitride, polycrystalline aluminum nitride, and quasi-single-crystal aluminum nitride; the particle size of the aluminum nitride is 80-100 μm.

7. The non-silicon thermally conductive pad according to claim 6, characterized in that: The alumina includes one or more of spherical alumina, quasi-spherical alumina, single-crystal alumina, polycrystalline alumina, and quasi-single-crystal alumina; the particle size of the alumina is 0.5-40 μm.

8. The non-silicon thermally conductive pad according to claim 7, characterized in that: The alumina includes spherical alumina and single-crystal alumina; the particle size of the single-crystal alumina is 0.5-1 μm, and the particle size of the spherical alumina is 10-40 μm.

9. The non-silicon thermally conductive pad according to claim 8, characterized in that: The mass ratio of the single crystal alumina to the spherical alumina is (3-5):

1.

10. A method for preparing a non-silicon thermally conductive gasket according to any one of claims 1 to 9, characterized in that: include: S1. Mix the antioxidant and non-silicon polymer, the treatment agent and the thermal conductive filler, and stir at 60-80°C for 30-60 minutes; S2, add cross-linking agent and catalyst, raise the temperature to 110-130°C, and stir under vacuum for 30-60 minutes; S3, discharging and calendering, and the product is obtained.

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