Elastomer composite material as well as preparation method and application thereof

Abstract

The invention provides an elastomer composite material as well as a preparation method and application thereof. The method comprises the following steps: pre-stirring hydroxyl silicone oil and liquid metal at room temperature for 0.5-3 minutes, then adding a cross-linking agent and a catalyst, stirring at room temperature for 3-10 minutes, and curing at room temperature for 2-4 hours to obtain the elastomer composite material. Starting from the design of the polymer matrix, the polymer matrix is prepared from the hydroxyl silicone oil, the cross-linking agent and the catalyst, and the polymer matrix is compounded with the gallium-indium alloy, so that the elastomer composite material with high tensile strength, high thermal conductivity and low modulus, of which the elongation at break is up to 450%, the thermal conductivity is up to 4.56 W / (m.K) and the Young modulus is up to 390kPa, can be prepared.

Description

Technical Field

[0001] The present invention relates to the technical field of materials, and in particular to an elastomer composite material and a preparation method and application thereof. Background Art

[0002] With the development of flexible electronics, wearable electronics and mobile devices, the miniaturization of electronic devices and the rapidly increasing power density have brought new challenges to thermal management. The reliability of these electronic devices is significantly affected by their operating temperature. Thermal management has become a key issue for the reliable and efficient operation of electronic devices, and the demand for thermal interface materials with high thermal conductivity is growing. However, materials with high thermal conductivity are usually rigid and show poor mechanical properties, which cannot meet the mechanical properties requirements of miniaturization for high thermal conductivity materials.

[0003] There is still a great demand for thermal interface materials (TIMs) with high thermal conductivity, low modulus and stretchability. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides an elastomer composite material and a preparation method and application thereof.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] The invention provides an elastomer composite material, which is prepared from hydroxy silicone oil, liquid metal, a crosslinking agent and a catalyst.

[0007] Furthermore, the volume fraction of the added amount of the liquid metal is greater than 40% and less than or equal to 70%.

[0008] Furthermore, the liquid metal includes at least one of a gallium-indium alloy and a gallium-indium-tin alloy; wherein the mass fraction of gallium in the gallium-indium alloy is 75% to 75.5%, and the mass fraction of indium is 24.5% to 25%; the mass fraction of gallium in the gallium-indium-tin alloy is 62% to 72%, the mass fraction of indium is 15.5% to 25.5%, and the mass fraction of tin is 7.5% to 17.5%.

[0009] Furthermore, the viscosity of the hydroxy silicone oil is 500 mpa·s to 50,000 mpa·s.

[0010] Furthermore, the hydroxy silicone oil is specifically one or more of αω-dihydroxy polydimethylsiloxane, hydroxyalkyl di-terminated polydimethylsiloxane or hydroxy-terminated diphenyl dimethyl.

[0011] Furthermore, the molar ratio of the crosslinking agent to the hydroxy silicone oil is 4:1 to 10:1.

[0012] Furthermore, the cross-linking agent is specifically decyltrimethoxysilane; the catalyst is specifically dibutyltin dilaurate, and the mass fraction of the dibutyltin dilaurate is 0.1wt% to 0.6wt% of the hydroxy silicone oil.

[0013] The present invention also provides a method for preparing the above-mentioned elastomer composite material, which comprises the following steps: pre-stirring the hydroxy silicone oil and liquid metal at room temperature for 0.5 to 3 minutes, then adding a crosslinking agent and a catalyst, stirring at room temperature for 3 to 10 minutes, and curing at room temperature for 2 to 4 hours to obtain the elastomer composite material.

[0014] Furthermore, the room temperature curing temperature is 20°C to 30°C.

[0015] The present invention also provides applications of the above-mentioned elastomer composite material in the fields of flexible electronics, wearable electronic devices and mobile devices.

[0016] Compared with the prior art, the technical solution provided by the present invention has at least the following advantages:

[0017] The present invention provides an elastomer composite material and a preparation method and application thereof. The present invention starts from designing a polymer matrix, prepares a polymer matrix through hydroxy silicone oil, a crosslinking agent and a catalyst, and compounds it with a gallium-indium alloy to prepare an elastomer composite material with high tensile strength, high thermal conductivity and low modulus, with a maximum elongation at break of 450%, a maximum thermal conductivity of 4.56 W / (m·K) and a maximum Young's modulus of 390 kPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplifications do not constitute limitations on the embodiments. Unless otherwise stated, the pictures in the drawings do not constitute proportional limitations.

[0019] Figure 1 It is a flow chart of the preparation of the elastomer composite material in the present invention. DETAILED DESCRIPTION

[0020] Thermal interface materials are elastomeric composites consisting of a polymer matrix and thermally conductive fillers. Most researchers overfill fillers to optimize the thermal conductivity of TIMs, however this approach significantly reduces the tensile properties of TIMs and increases the elastic modulus of the composite, inevitably compromising its mechanical properties. It is currently critical to use new polymer matrix methods to balance the mechanical and thermal properties of elastomeric composites.

[0021] The present invention selects a suitable polymer skeleton and a cross-linking agent and a catalyst to form a polymer matrix, and uses an alloy that is liquid at room temperature, that is, liquid metal, as a filler. Compared with other high-conductivity and rigidity fillers, the unique properties of liquid metal represented by gallium-indium alloy can greatly improve the mechanical properties of the composite material. The oxide layer formed by the gallium-indium alloy in the air can increase the viscosity of the droplets, and finally evenly distribute in the polymer matrix. When the polymer matrix is ​​stretched, the liquid metal particles can form a synergistic effect with the matrix, and the liquid metal is also stretched from a sphere to an ellipsoid, so that the TIMs have excellent mechanical properties. Figure 1 This is a flow chart for preparing the elastomer composite material in the present invention, which includes premixing hydroxy silicone oil and liquid metal, adding a crosslinking agent and a catalyst into the premix, further stirring, and curing to obtain the elastomer composite material.

[0022] The present invention is described in detail below in conjunction with specific implementation modes.

[0023] Example 1

[0024] (A) 6 g of hydroxy silicone oil (αω, dihydroxypolydimethylsiloxane) and 57.32 g (volume fraction 60%) of gallium-indium alloy (wherein the mass fraction of gallium is 75% and the mass fraction of indium is 25%) are premixed in a planetary stirrer at room temperature for 30 seconds to obtain a premix of hydroxy silicone oil and gallium-indium alloy.

[0025] (B) 0.4 g of decyltrimethoxysilane (the molar ratio of decyltrimethoxysilane to hydroxysilicone oil is 8:1) and a catalyst dibutyltin dilaurate (0.3 wt%) were added to the premix of hydroxysilicone oil and gallium-indium alloy, mixed in a planetary mixer at room temperature for 2 min, and poured into a polytetrafluoroethylene mold.

[0026] (C) Curing in a mold at room temperature for 4 hours to obtain the elastomer composite material of the present invention.

[0027] Example 2

[0028] (A) 6 g of hydroxy silicone oil (αω, dihydroxypolydimethylsiloxane) and 88.74 g (70% by volume) of gallium-indium alloy (wherein the mass fraction of gallium is 75% and the mass fraction of indium is 25%) are premixed in a planetary stirrer at room temperature for 30 seconds to obtain a premix of hydroxy silicone oil and gallium-indium alloy.

[0029] (B) 0.5 g of decyltrimethoxysilane (the molar ratio of decyltrimethoxysilane to hydroxysilicone oil is 10:1) and a catalyst dibutyltin dilaurate (0.3 wt%) were added to the premix of hydroxysilicone oil and gallium-indium alloy, mixed in a planetary mixer at room temperature for 2 min, and poured into a polytetrafluoroethylene mold.

[0030] (C) Curing in a mold at room temperature for 4 hours to obtain the elastomer composite material of the present invention.

[0031] Example 3

[0032] The formula and steps used in Example 1 are the same, except that the obtained elastomer composite material is pressed multiple times before the thermal conductivity test.

[0033] Example 4

[0034] The formula and steps used in Example 2 are the same, except that the obtained elastomer composite material is pressed multiple times before the thermal conductivity test.

[0035] Example 5

[0036] (A) 6 g of hydroxyalkyl di-terminated polydimethylsiloxane and 88.5 g of gallium-indium-tin alloy (60% by volume) (wherein the mass fraction of gallium is 68.5%, the mass fraction of indium is 21.5%, and the mass fraction of tin is 10%) are premixed in a planetary stirrer at room temperature for 30 seconds to obtain a premix of hydroxyalkyl di-terminated polydimethylsiloxane and gallium-indium-tin alloy.

[0037] (B) To the premix of hydroxyalkyl di-terminated polydimethylsiloxane and gallium indium tin alloy, 0.4 g of decyltrimethoxysilane (the molar ratio of decyltrimethoxysilane to hydroxy silicone oil is 8:1) and catalyst dibutyltin dilaurate (0.4 wt%) were added, mixed in a planetary mixer at room temperature for 2 min, and poured into a polytetrafluoroethylene mold.

[0038] (C) Curing in a mold at room temperature for 4 hours to obtain the elastomer composite material of the present invention.

[0039] Example 6

[0040] (A) 6 g of hydroxyalkyl di-terminated polydimethylsiloxane and 118 g of gallium-indium-tin alloy (70% by volume) (wherein the mass fraction of gallium is 68.5%, the mass fraction of indium is 21.5%, and the mass fraction of tin is 10%) are premixed in a planetary stirrer at room temperature for 30 seconds to obtain a premix of hydroxyalkyl di-terminated polydimethylsiloxane and gallium-indium-tin alloy.

[0041] (B) To the premix of hydroxyalkyl di-terminated polydimethylsiloxane and gallium indium tin alloy, add 0.5 g of decyltrimethoxysilane (the molar ratio of decyltrimethoxysilane to hydroxy silicone oil is 10:1) and catalyst dibutyltin dilaurate (0.5 wt%), mix in a planetary mixer at room temperature for 2 min, and pour into a polytetrafluoroethylene mold.

[0042] (C) Curing in a mold at room temperature for 4 hours to obtain the elastomer composite material of the present invention.

[0043] Test method:

[0044] (1) Thermal conductivity test:

[0045] The standard test method for determining vertical thermal conductivity by the steady-state method. The test instrument is the Hot Disk thermal constant analyzer. The specific steps are as follows: Place the temperature probe between two pieces of elastomer composite materials. During the test, a constant output current is passed through the probe. Due to the increase in temperature, the resistance of the probe changes, resulting in a certain degree of voltage drop at both ends of the probe. Due to the different thermal conductivity of the samples, the heat dissipation of the probe is different, and the voltage change generated is also different. Therefore, by recording the change in voltage over a period of time, the thermal conductivity of the sample under test can be obtained.

[0046] (2) Mechanical properties test:

[0047] The mechanical properties of the samples were measured using a universal tensile machine (Instron 4465). The samples were cut into dumbbell shapes and all mechanical tests were performed at room temperature at a tensile speed of 10 mm / min.

[0048] Comparative Examples 1 to 9 are disclosed thermally conductive materials. The thermal conductivity, elongation at break, and Young's modulus of the thermal interface materials provided by Examples 1 to 4 are tested according to the above method. The results are shown in Table 1:

[0049]

[0050]

[0051] It can be seen from Comparative Examples 1 to 9 in Table 1 that it is difficult for current thermal conductive materials to simultaneously meet high elongation at break and low Young's modulus while meeting high thermal conductivity. When the Young's modulus is at a relatively low value (such as a Young's modulus value <500kPa), the thermal conductivity of the current thermal conductive material ranges from 0.36 to 1.5, which is much lower than the thermal conductivity of the thermal conductive material in the technical solution provided by the present invention. For materials with higher elongation at break (such as elongation at break of 100 to 600%), the thermal conductivity ranges from 0.36 to 1.69W / m·K, which is also much lower than the thermal conductivity of the thermal conductive material in the technical solution provided by the present invention. For thermal conductive materials with a thermal conductivity greater than 2, their Young's modulus can exceed 600kPa, which is much higher than the Young's modulus of the thermal conductive material in the technical solution provided by the present invention. Therefore, compared with current thermal conductive materials, the thermal conductive material of the present invention simultaneously has the characteristics of high thermal conductivity, low Young's modulus and high elongation at break.

[0052] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for implementing the present application, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the present application. Any person skilled in the art can make their own changes and modifications without departing from the spirit and scope of the present application, so the scope of protection of the present application shall be based on the scope defined in the claims.

Claims

1. An elastomer composite material, characterized in that: The elastomer composite material is prepared from hydroxy silicone oil, liquid metal, a cross-linking agent and a catalyst.

2. The elastomer composite material according to claim 1, characterized in that: The volume fraction of the added amount of the liquid metal is greater than 40% and less than or equal to 70%.

3. The elastomer composite material according to claim 1, characterized in that: The liquid metal includes at least one of a gallium-indium alloy and a gallium-indium-tin alloy; wherein the mass fraction of gallium in the gallium-indium alloy is 75% to 75.5%, and the mass fraction of indium is 24.5% to 25%; the mass fraction of gallium in the gallium-indium-tin alloy is 62% to 72%, the mass fraction of indium is 15.5% to 25.5%, and the mass fraction of tin is 7.5% to 17.5%.

4. The elastomer composite material according to claim 1, characterized in that: The viscosity of the hydroxy silicone oil is 500 mpa·s to 50000 mpa·s.

5. The elastomer composite material according to claim 4, characterized in that: The hydroxy silicone oil is specifically one or more of αω-dihydroxy polydimethylsiloxane, hydroxyalkyl di-terminated polydimethylsiloxane or hydroxy-terminated diphenyl dimethyl.

6. The elastomer composite material according to claim 1, characterized in that: The molar ratio of the crosslinking agent to the hydroxy silicone oil is 4:1 to 10:

1.

7. The elastomer composite material according to claim 1, characterized in that: The cross-linking agent is specifically decyltrimethoxysilane; the catalyst is specifically dibutyltin dilaurate, and the mass fraction of the dibutyltin dilaurate is 0.1wt% to 0.6wt% of the hydroxy silicone oil.

8. The method for preparing the elastomer composite material according to any one of claims 1 to 7, characterized in that: The method consists of the following steps: The hydroxy silicone oil and liquid metal are pre-stirred at room temperature for 0.5 to 3 minutes, and then a cross-linking agent and a catalyst are added, stirred at room temperature for 3 to 10 minutes, and cured at room temperature for 2 to 4 hours to obtain an elastomer composite material.

9. The method for preparing the elastomer composite material according to claim 8, characterized in that: The room temperature curing temperature is 20°C to 30°C.

10. Use of the elastomer composite material as claimed in claim 9 in electronic equipment.

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