Non‑silicone thermal pad and preparation method therefor
By using non-silicone polymers and alumina and aluminum nitride fillers with specific particle sizes, as well as coupling agents, the problem of silicone oil overflow is solved, resulting in non-silicone thermal pads with high thermal conductivity and hardness, suitable for heat dissipation in electronic products.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- SHANGHAI ALLIED PLASTIC IND
- Filing Date
- 2025-05-16
- Publication Date
- 2026-06-18
AI Technical Summary
The silicone oil component in existing thermal pads is prone to overflow at high temperatures, affecting the performance of electronic products, and there is room for improvement in thermal conductivity.
Non-silicone polymers such as polyester polyols are used as the main raw materials, combined with hydrogenated MDI crosslinking agents and alumina and aluminum nitride thermally conductive fillers of specific particle sizes. Continuous thermally conductive channels are formed through crosslinking curing and close packing. Coupling agents are added to improve interfacial compatibility, and vacuum treatment reduces impurity content.
To prevent silicone oil from overflowing at high temperatures, increase the thermal conductivity to over 10 W/m·K, and ensure a hardness of not less than 50 Shore 00, thereby enhancing product stability and thermal conductivity.
Smart Images
Figure PCTCN2025095331-FTAPPB-I100001
Abstract
Description
A non-silicone thermal pad and its preparation method Technical Field
[0001] This invention relates to the field of thermally conductive materials, and more specifically, to a non-silicone thermally conductive pad and its preparation method. Background Technology
[0002] With the rapid development of electronic information technology, the miniaturization trend of electronic products is becoming increasingly apparent. However, miniaturization has also brought new problems, namely, the heat generated by electronic products during operation is difficult to dissipate effectively, which can damage the device, accelerate component aging, shorten service life, and even lead to malfunction. Therefore, how to quickly conduct and dissipate heat has become a key technical problem that urgently needs to be solved in current electronic products. In the field of thermal conductive materials, thermal pads have received widespread attention due to their excellent performance. Thermal pads are mainly made of silicone oil as the main raw material, with the addition of fillers such as metal oxides, and are processed through special processes. They have the characteristics of low thermal resistance, high thermal conductivity, good insulation, and strong sealing, and can transfer heat between heat-generating and heat-dissipating parts through tiny gaps in the pad, thereby effectively achieving rapid heat dissipation. However, the silicone oil component in thermal pads may leak out under high-temperature environments. Especially in electronic products, the volatilization of small siloxane molecules in silicone oil can adsorb onto the interface surface, which can indirectly affect the performance of the device. Therefore, finding a new type of thermal conductive material that does not have the problem of silicone oil leakage is particularly important. Non-silicone thermal pads have emerged in this context. Compared to thermal pads, the biggest advantage of non-silicone thermal pads is that they do not contain silicone oil. Therefore, they can effectively avoid problems caused by silicone oil overflow, enabling products to work and operate more stably in high-temperature environments.
[0003] The prior art CN118185325A discloses a high-performance non-silicone thermal conductive ester and its preparation method. The raw materials mainly include non-silicone oil, thermally conductive composite filler, treatment agent and antioxidant. The thermal conductivity of the product can reach more than 5.2 W / m·K, but there is still significant room for improvement in thermal conductivity.
[0004] Therefore, how to prepare a non-silicon thermal pad with high thermal conductivity and high hardness is an industry-wide technical problem that is currently being focused on in this field. Summary of the Invention
[0005] To address the aforementioned technical problems, the first aspect of this invention provides a non-silicone thermally conductive pad, the raw materials for which include: a non-silicone polymer, a thermally conductive filler, a treatment agent, an antioxidant, a crosslinking agent, and a catalyst.
[0006] As an feasible example, the raw materials for preparing the non-silicone thermal pad include, by weight parts: 5-10 parts non-silicone polymer, 180-200 parts thermally conductive filler, 0.3-0.5 parts treatment agent, 0.3-0.5 parts antioxidant, 0.4-1 parts crosslinking agent, and 0.03-0.2 parts catalyst.
[0007] Furthermore, the raw materials for preparing the non-silicone thermal pad include, by weight, 6.2 parts non-silicone polymer, 192 parts thermally conductive filler, 0.4 parts treatment agent, 0.4 parts antioxidant, 0.9 parts crosslinking agent, and 0.1 parts catalyst.
[0008] As an implementable example, the non-silicone polymer includes one or more of the following: polyester polyols, polyether polyols, polyurethane resins, acrylate resins, polystyrene resins, and epoxy resins.
[0009] Furthermore, the non-silicone polymer is a polyester polyol, and the polyester polyol may be graded PH-100D, purchased from Ito Oil Co., Ltd.
[0010] To address the technical shortcomings of existing silicone oil-based thermal conductive materials, such as silicone oil easily overflowing at high temperatures and causing product damage, this invention preferentially uses non-silicone polymer polyester polyol as the raw material. Under the action of catalysts and crosslinking agents, it can crosslink and cure, which not only improves the firmness between thermally conductive filler particles, but also further enhances the mechanical properties of non-silicone thermal conductive pads, making their application range wider.
[0011] As an implementable example, the thermally conductive filler includes one or more of the following: carbon nanotubes, alumina, 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 example, the aluminum nitride includes one or more of the following: spherical aluminum nitride, near-spherical aluminum nitride, monocrystalline aluminum nitride, polycrystalline aluminum nitride, and near-monocrystalline aluminum nitride.
[0016] As an implementable example, the aluminum nitride has a particle size of 80-100 μm, including one or more of 80 μm, 90 μm, and 100 μm.
[0017] Furthermore, the aluminum nitride comprises spherical aluminum nitride with a particle size of 80 μm.
[0018] As an implementable example, the alumina includes one or more of the following: spherical alumina, near-spherical alumina, monocrystalline alumina, polycrystalline alumina, and near-monocrystalline alumina.
[0019] As an implementable example, the alumina has a particle size of 0.5-40 μm, including one or more of the following: 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 single-crystal alumina is 0.5-1 μm, and the particle size of 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 particles with a diameter of 40 μm, being larger, can form a "skeleton" in the thermally conductive filler, providing the main heat conduction path. Spherical alumina particles with a diameter of 10 μm have a moderate particle size, which can fill the gaps between the 40 μm particles, further increasing the continuity of the heat conduction channel. Single-crystal alumina particles with a diameter of 0.5 μm, being the smallest particles, can penetrate into the tiny gaps between larger particles, forming a tight packing, reducing thermal resistance, and providing higher thermal conductivity through the single-crystal structure. In addition, due to the more ordered internal lattice structure, single-crystal alumina has better thermal conductivity than polycrystalline alumina, reducing heat scattering and heat accumulation at grain boundaries. 0.5 μm single-crystal alumina can act as an efficient thermally conductive "bridge," connecting larger alumina particles to form a more efficient thermally conductive network. By compounding three types of alumina with different particle sizes, a thermally conductive filler system with a wide particle size distribution can be obtained, which is conducive to forming a dense packing and continuous thermally conductive channels, thereby improving the overall thermal conductivity of the non-silicone thermally conductive pad. Aluminum nitride is a material with a high thermal conductivity, with a theoretical thermal conductivity of up to 600 W / m·K, which is much higher than that of alumina. In this invention, large spherical aluminum nitride particles with a particle size of 80 μm are added to the thermally conductive filler system, which can further improve the thermal conductivity and hardness of the non-silicone thermally conductive pad, so that the thermal conductivity of the product can reach more than 10 W / m·K and the hardness is not less than 50 Shore 00.
[0026] As an example of an implementable method, the treatment agent includes one or more of the following: coupling agent, dispersant, plasticizer, and water-absorbing agent.
[0027] Furthermore, the treatment agent is a coupling agent.
[0028] As an implementable example, the coupling agent includes one or more of the following: octyltrimethoxysilane, dodecyltrimethoxysilane, n-octyltriethoxysilane, vinyltrimethoxysilane, hydroxyl polydimethylsiloxane, and diol-based polydimethylsiloxane.
[0029] Furthermore, the coupling agent is dodecyltrimethoxysilane.
[0030] While the coupling agent dodecyltrimethoxysilane itself has a low thermal conductivity, its coating on the surface of the thermally conductive filler can reduce the system's thermal resistance by minimizing defects and voids. Simultaneously, the coupling agent improves the interfacial compatibility between the thermally conductive filler and the matrix material, facilitating smoother heat transfer. Therefore, the addition of the coupling agent can significantly improve the thermal conductivity of thermally conductive materials. Furthermore, dodecyltrimethoxysilane can enhance the interaction and compatibility between the various raw materials, resulting in a denser packing and continuous thermal channels within the non-silicone thermally conductive pad, further reducing the product's thermal resistance and increasing its thermal conductivity.
[0031] This invention does not further limit the selection of antioxidants. Any component that can play an antioxidant and anti-aging role is acceptable, 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 example, the crosslinking 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 groups of hydrogenated MDI have high reactivity and can undergo nucleophilic addition reactions with the hydroxyl groups in polyester polyols to form polyurethane components with high crosslinking density, which is beneficial to improving the hardness of non-silicone thermal pads.
[0035] As an implementable example, the catalyst comprises at least one of the following: dibutyltin dilaurate, dibutyltin dioctanoate, N,N-dimethylethanolamine, stannous octanoate, dibutyltin diacetate, di(dodecyl sulfide)dibutyltin, N-methylmorpholine, N-ethylmorpholine, N-methylimidazolium, triethanolamine, and triethylamine.
[0036] Furthermore, the catalyst is dibutyltin dioctanoate.
[0037] A second aspect of the present invention provides a method for preparing a non-silicone thermal pad, comprising:
[0038] S1. Mix the antioxidant, non-silicone polymer, treatment agent, and thermally conductive filler, and stir at 60-80℃ for 30-60 minutes.
[0039] S2. Add crosslinking agent and catalyst, heat to 110-130℃, and stir under vacuum for 30-60 minutes.
[0040] S3. Discharge, calender, and obtain the final product. Beneficial effects
[0041] (i) In this invention, non-silicone polymer polyester polyol is selected as the main raw material to replace silicone oil, so that the non-silicone thermal pad will not leak oil under high temperature environment.
[0042] (ii) The present invention selects hydrogenated MDI as a crosslinking agent and blends it with polyester polyol, which can further improve the hardness of the product and its adhesion performance on electronic products.
[0043] (III) This invention selects spherical alumina with a particle size of 40 μm, and combines spherical alumina with a particle size of 10 μm and single-crystal alumina with a particle size of 0.5 μm. This allows for the formation of a dense packing and continuous thermal conductive channels, thereby improving the overall thermal conductivity of the non-silicon thermal pad.
[0044] (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 80μm to the thermally conductive filler system, which can make the thermal conductivity of the product reach more than 10W / m·K and the hardness not less than 50 Shore 00.
[0045] (v) The present invention performs a heating and vacuuming operation during the preparation of non-silicone thermal pads, 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 non-silicone thermal pads. Detailed Implementation
[0046] Example 1
[0047] The first aspect of this example provides a non-silicone thermally conductive pad, the raw materials for which, by mass parts, include: 6.2 parts of non-silicone polymer, 192 parts of thermally conductive filler, 0.4 parts of treatment agent, 0.4 parts of antioxidant, 0.9 parts of crosslinking agent, and 0.1 parts of catalyst.
[0048] The non-silicone polymer is a polyester polyol, brand name PH-100D, purchased from Ito Oil Co., Ltd.
[0049] The thermally conductive filler, by mass parts, consists of: 102 parts of spherical aluminum nitride with a particle size of 80 μm, 40 parts of spherical alumina with a particle size of 40 μm, 30 parts of spherical alumina with a particle size of 10 μm, and 20 parts of single-crystal alumina with a particle size of 0.5 μm, all of which are commercially available products.
[0050] The treatment agent is dodecyltrimethoxysilane.
[0051] The antioxidant mentioned is antioxidant 1010, a commonly available commercial product.
[0052] The crosslinking agent is hydrogenated MDI.
[0053] The catalyst is dibutyltin dioctanoate.
[0054] The second aspect of this example provides a method for preparing a non-silicone thermal pad, including:
[0055] S1. Mix the antioxidant, non-silicone polymer, treatment agent, and thermally conductive filler, and stir at 65°C for 30 minutes.
[0056] S2. Add crosslinking agent and catalyst, heat to 120°C, and stir under vacuum for 30 minutes.
[0057] S3. Discharge the material and roll it into a 2mm thick non-silicone thermal pad.
[0058] Example 2
[0059] The first aspect of this example provides a non-silicone thermally conductive pad, the raw materials for which, by mass parts, include: 5 parts non-silicone polymer, 193 parts thermally conductive filler, 0.5 parts treatment agent, 0.5 parts antioxidant, 0.4 parts crosslinking agent, and 0.03 parts catalyst.
[0060] The non-silicone polymer is a polyester polyol, brand name PH-100D, purchased from Ito Oil Co., Ltd.
[0061] The thermally conductive filler, by mass parts, consists of: 60 parts of spherical aluminum nitride with a particle size of 120 μm, 50 parts of spherical alumina with a particle size of 70 μm, 46 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 commercially available products.
[0062] The treatment agent is dodecyltrimethoxysilane.
[0063] The antioxidant mentioned is antioxidant 1010, a commonly available commercial product.
[0064] The crosslinking agent is hydrogenated MDI.
[0065] The catalyst is dibutyltin dioctanoate.
[0066] The second aspect of this example provides a method for preparing a non-silicone thermal pad, including:
[0067] S1. Mix the antioxidant, non-silicone polymer, treatment agent, and thermally conductive filler, and stir at 65°C for 30 minutes.
[0068] S2. Add crosslinking agent and catalyst, heat to 120°C, and stir under vacuum for 30 minutes.
[0069] S3. Discharge the material and roll it into a 2mm thick non-silicone thermal pad.
[0070] Example 3
[0071] The first aspect of this example provides a non-silicone thermally conductive pad, the raw materials for which, by mass parts, include: 10 parts of non-silicone polymer, 184 parts of thermally conductive filler, 0.3 parts of treatment agent, 0.3 parts of antioxidant, 1 part of crosslinking agent, and 0.2 parts of catalyst.
[0072] The non-silicone polymer is a polyester polyol, brand name PH-100D, purchased from Ito Oil Co., Ltd.
[0073] The thermally conductive filler, by mass parts, consists of: 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 commercially available products.
[0074] The treatment agent is dodecyltrimethoxysilane.
[0075] The antioxidant mentioned is antioxidant 1010, a commonly available commercial product.
[0076] The crosslinking agent is hydrogenated MDI.
[0077] The catalyst is dibutyltin dioctanoate.
[0078] The second aspect of this example provides a method for preparing a non-silicone thermal pad, including:
[0079] S1. Mix the antioxidant, non-silicone polymer, treatment agent, and thermally conductive filler, and stir at 65°C for 30 minutes.
[0080] S2. Add crosslinking agent and catalyst, heat to 120°C, and stir under vacuum for 30 minutes.
[0081] S3. Discharge the material and roll it into a 2mm thick non-silicone thermal pad.
[0082] Example 4
[0083] The first aspect of this example provides a non-silicone thermally conductive pad, the raw materials for which, by mass parts, include: 6.05 parts of non-silicone polymer, 193 parts of thermally conductive filler, 0.4 parts of treatment agent, 0.4 parts of antioxidant, 0.1 parts of crosslinking agent, and 0.03 parts of catalyst.
[0084] The non-silicone polymer is a polyester polyol, brand name PH-100D, purchased from Ito Oil Co., Ltd.
[0085] The thermally conductive filler, by mass parts, comprises: 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 near-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 commercially available products.
[0086] The treatment agent is dodecyltrimethoxysilane.
[0087] The antioxidant mentioned is antioxidant 1010, a commonly available commercial product.
[0088] The crosslinking agent is hydrogenated MDI.
[0089] The catalyst is dibutyltin dioctanoate.
[0090] The second aspect of this example provides a method for preparing a non-silicone thermal pad, including:
[0091] S1. Mix the antioxidant, non-silicone polymer, treatment agent, and thermally conductive filler, and stir at 65°C for 30 minutes.
[0092] S2. Add crosslinking agent and catalyst, heat to 120°C, and stir under vacuum for 30 minutes.
[0093] S3. Discharge the material and roll it into a 2mm thick non-silicone thermal pad.
[0094] Example 5
[0095] The first aspect of this example provides a non-silicone thermally conductive pad, the raw materials for which, by mass parts, include: 6.07 parts of non-silicone polymer, 193 parts of thermally conductive filler, 0.4 parts of treatment agent, 0.4 parts of antioxidant, 0.1 parts of crosslinking agent, and 0.03 parts of catalyst.
[0096] The non-silicone polymer is a polyester polyol, brand name PH-100D, purchased from Ito Oil Co., Ltd.
[0097] The thermally conductive filler comprises, by mass parts: 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.
[0098] The treatment agent is dodecyltrimethoxysilane.
[0099] The antioxidant mentioned is antioxidant 1010, a common commercially available product.
[0100] The crosslinking agent is hydrogenated MDI.
[0101] The catalyst is dibutyltin dioctanoate.
[0102] The second aspect of this example provides a method for preparing a non-silicone thermal pad, including:
[0103] S1. Mix the antioxidant, non-silicone polymer, treatment agent, and thermally conductive filler, and stir at 65°C for 30 minutes.
[0104] S2. Add crosslinking agent and catalyst, heat to 120°C, and stir under vacuum for 30 minutes.
[0105] S3. Discharge the material and roll it into a 2mm thick non-silicone thermal pad.
[0106] Performance Evaluation
[0107] Test subject: Non-silicone thermal pads prepared in Examples 1-5.
[0108] Test items: thermal conductivity and hardness.
[0109] The test methods and test results are detailed in Table 1.
[0110] Table 1
[0111] The experimental results of Examples 1 and 4-5 above show that 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 thermally conductive fillers can further improve the thermal conductivity and hardness of non-silicon thermal pads.
Claims
1. A non-silicon thermally conductive gasket, characterized by, The preparation raw materials of the non-silicon heat-conducting gasket comprise 5-10 parts of non-silicon polymer, 180-200 parts of heat-conducting filler, 0.3-0.5 parts of treating agent, 0.3-0.5 parts of antioxidant, 0.4-1 parts of crosslinking agent and 0.03-0.2 parts of catalyst according to mass fraction.
2. The non-silicon heat-conducting gasket according to claim 1, wherein The catalyst comprises at least one of dibutyl tin dilaurate, dibutyl tin dioctoate, N,N-dimethyl ethanolamine, stannous octoate, dibutyl tin diacetate, bis(dodecylthio)dibutyl tin, N-methyl morpholine, N-ethyl morpholine, N-methyl imidazole, triethanolamine and triethylamine.
3. The non-silicon heat-conducting gasket of claim 1, wherein, The non-silicon polymer comprises one or more of polyester polyol, polyether polyol, polyurethane resin, acrylate resin, polystyrene resin and epoxy resin.
4. The non-silicon thermally-conductive gasket of claim 1, wherein, The heat-conducting filler comprises one or more of carbon nanotube, aluminum oxide, zinc oxide, boron nitride, aluminum nitride, aluminum powder, graphene and silicon carbide.
5. The non-silicon heat-conducting gasket according to claim 4, wherein The heat-conducting filler comprises aluminum nitride and aluminum oxide, and the mass ratio of aluminum nitride to aluminum oxide is (100-115):(80-100).
6. The non-silicon heat-conducting gasket according to claim 5, wherein The aluminum nitride comprises one or more of spherical aluminum nitride, quasi-spherical aluminum nitride, single-crystal aluminum nitride, polycrystalline aluminum nitride and quasi-single-crystal aluminum nitride, and the particle size of the aluminum nitride is 80-100 μm.
7. The non-silicon heat-conducting gasket according to claim 6, wherein The aluminum oxide comprises one or more of spherical aluminum oxide, quasi-spherical aluminum oxide, single-crystal aluminum oxide, polycrystalline aluminum oxide and quasi-single-crystal aluminum oxide, and the particle size of the aluminum oxide is 0.5-40 μm.
8. The non-silicon heat-conducting gasket according to claim 7, wherein The aluminum oxide comprises spherical aluminum oxide and single-crystal aluminum oxide, the particle size of the single-crystal aluminum oxide is 0.5-1 μm, and the particle size of the spherical aluminum oxide is 10-40 μm.
9. The non-silicon heat-conducting gasket of claim 8, wherein, The mass ratio of the single-crystal aluminum oxide to the spherical aluminum oxide is (3-5):
1.
10. A method of producing the non-silicon heat-conducting gasket according to any one of claims 1 to 9, characterized by, The method comprises the following steps: S1, mixing the antioxidant, non-silicon polymer, treating agent and heat-conducting filler, and stirring at 60-80 ℃ for 30-60 min; S2, adding the crosslinking agent and catalyst, and stirring at 110-130 ℃ under vacuum for 30-60 min; S3, discharging and calendering to obtain the product.