High-thermal-conductivity low-viscosity silica gel material and preparation method thereof

Abstract

The invention provides a high-thermal-conductivity and low-viscosity silica gel material and a preparation method thereof. The high-thermal-conductivity and low-viscosity silica gel material comprises the following components in parts by mass: 60-70 parts of a silica gel matrix, 30-40 parts of a thermal conductive filler, 5-8 parts of a functional additive, 5-8 parts of an auxiliary additive, 2-3 parts of polytetrafluoroethylene and 5-10 parts of a fluorocarbon solvent. According to the invention, polydimethylsiloxane, polyethylene terephthalate and gamma-trifluoropropyl methyl polysiloxane with excellent thermal stability and chemical stability are selected as matrix materials, so that the molecular structure and crosslinking density of silica gel can be optimized, and the characteristic of low viscosity is realized; the silica gel material has a high heat conductivity coefficient and excellent dispersity by introducing the carbon nanotubes with high heat conductivity, graphene, aluminum oxide and boron nitride, the heat conductivity of the silica gel material can be effectively improved, and the dispersity of the heat-conducting filler in a silica gel matrix can be improved by adding a proper amount of functional aids such as the flatting agent and the coupling agent, so that the heat conductivity of the silica gel material is improved. The viscosity is reduced, and the mechanical property of the material is enhanced.

Description

Technical Field

[0001] The invention relates to a silicone material and a preparation method thereof, in particular to a high thermal conductivity and low viscosity silicone material and a preparation method thereof, belonging to the technical field of silicone materials. Background Art

[0002] Silicone material is a rubber material containing silicon, also known as silicone rubber. It has the advantages of being safe and non-toxic, insoluble in water and any solvents, non-toxic and tasteless, and stable in chemical properties. Silicone does not react with any substance except strong alkali and hydrofluoric acid. Silicone also has highly active adsorption materials and an open porous structure, so it has strong adsorption and can adsorb a variety of substances. Silicone can be formed by molding, injection, extrusion, calendering, infusion and other methods. These processes enable silicone to produce products with different shapes, hardness and uses. With the rapid development of electronic equipment, the requirements for heat dissipation performance are increasing. As an excellent thermal insulation and shock absorption material, silicone has been widely used in electronic equipment.

[0003] In the prior art, the thermal conductivity of silica gel materials is relatively poor, which is determined by its molecular structure and chemical properties. Silica gel is an organic polymer compound, and its molecular chain is mainly composed of silicon-oxygen bonds and organic groups. This structure makes silica gel have certain limitations in thermal conductivity;

[0004] Moreover, under the influence of its special molecular structure and chemical properties, the silicone molecular chains have a high mutual attraction, thus forming a strong cohesive force, which is manifested as the viscosity of the silicone material on a macro scale. Although the existence of viscosity makes the silicone material have a certain degree of adhesion and plasticity, in some applications that require low viscosity, the high viscosity of silicone will become a limiting factor for its use;

[0005] Therefore, the traditional silicone material has poor thermal conductivity and high viscosity, and it is difficult to meet the application requirements of high thermal conductivity and low viscosity. Therefore, a high thermal conductivity and low viscosity silicone material and a preparation method thereof are proposed. Summary of the invention

[0006] In view of this, the present invention provides a high thermal conductivity and low viscosity silicone material and a preparation method thereof to solve or alleviate the technical problems existing in the prior art and at least provide a beneficial choice.

[0007] The technical solution of the embodiment of the present invention is implemented as follows: a high thermal conductivity and low viscosity silicone material, comprising the following components by mass: 60-70 parts of silicone matrix, 30-40 parts of thermal conductive filler, 5-8 parts of functional additive, 5-8 parts of auxiliary additive, 2-3 parts of polytetrafluoroethylene, and 5-10 parts of fluorocarbon solvent;

[0008] The silica gel matrix comprises the following components in parts by mass: 25-30 parts of polydimethylsiloxane, 20-30 parts of polyethylene terephthalate, 15-20 parts of γ-trifluoropropylmethylpolysiloxane, 10-20 parts of a crosslinking agent and 2-5 parts of a catalyst;

[0009] The thermal conductive filler comprises the following components in parts by mass: 5-15 parts of carbon nanotubes, 3-10 parts of graphene, 1-3 parts of surfactant, 5-15 parts of aluminum oxide and 5-15 parts of boron nitride.

[0010] Further preferably, the functional additive includes the following components in parts by mass: 1-3 parts of a leveling agent, 1-2 parts of a coupling agent and 1-2 parts of a diluent, and the auxiliary additive includes the following components in parts by mass: 1-2 parts of a dye, 1-2 parts of an antibacterial agent and 1-3 parts of an antifungal agent.

[0011] More preferably, the cross-linking agent is an acrylic polymer, and the surfactant is trimethylsilylamine.

[0012] In addition, the present invention also provides a method for preparing a high thermal conductivity and low viscosity silicone material, comprising the following steps:

[0013] Step 1: pre-treating the thermal conductive filler to form a paste-like mixture;

[0014] Step 2: pre-mixing the base material and uniformly dispersing the base material by ultrasonic dispersion;

[0015] Step 3: Add the thermal conductive filler, the base material and the functional additive into the mixer and mix them thoroughly;

[0016] Step 4: Take out the mixed material and put it into a mold to perform a vulcanization reaction to shape the silicone material. The vulcanization reaction type is selected to be a condensation vulcanization reaction using an organic tin catalyst or an addition vulcanization reaction using a platinum catalyst;

[0017] Step 5: Heat treatment and surface treatment of the cured silicone material.

[0018] Further preferably, in step one, carbon nanotubes, graphene, surfactant, aluminum oxide and boron nitride are added to a sample tank, clean water is added in an equal proportion to the surfactant, and the mixture is homogenized using a non-invasive material homogenizer to fully break up the filler particles to form a mixture, and the mixture forms a non-flowing paste.

[0019] Further preferably, in step 2, polydimethylsiloxane, polyethylene terephthalate and γ-trifluoropropylmethylpolysiloxane are put into an ultrasonic disperser for mixing and dispersion.

[0020] Further preferably, in step three, the mixed raw materials are transferred to a defoaming machine for decompression defoaming treatment to remove bubbles generated during the mixing process.

[0021] Further preferably, in step one, MXene is added to the thermally conductive filler, and a combination of MXene and boron nitride is prepared using chemical vapor deposition technology, and the wettability and compatibility of the surfaces of carbon nanotubes and boron nitride are improved using a chemical modification method.

[0022] Further preferably, in step three, the pretreated raw materials are placed in a mixer, auxiliary additives are added, and high-speed stirring and mixing are performed. During the mixing process, the operating temperature of the mixer is 200°C-350°C, the mixing time is 30-40min, and the speed of the mixer is 200-300r / min.

[0023] Further preferably, in step five, polytetrafluoroethylene powder is dissolved in a fluorocarbon solvent to prepare a polytetrafluoroethylene solution, the polytetrafluoroethylene solution is evenly sprayed on the surface of the silicone material, and then the silicone material is heat treated. After the heat treatment, the thermal conductivity, viscosity and mechanical strength properties of the silicone material are tested.

[0024] Since the embodiments of the present invention adopt the above technical scheme, they have the following advantages: the present invention can optimize the molecular structure and cross-linking density of silica gel and achieve the characteristics of low viscosity by selecting polydimethylsiloxane, polyethylene terephthalate and γ-trifluoropropylmethylpolysiloxane with excellent thermal stability and chemical stability as the matrix material; by introducing carbon nanotubes, graphene, aluminum oxide and boron nitride with high thermal conductivity, the silica gel material can have a high thermal conductivity coefficient and excellent dispersibility, which can effectively improve the thermal conductivity of the silica gel material; and by adding an appropriate amount of functional additives such as leveling agents and coupling agents, the dispersibility of thermal conductive fillers in the silica gel matrix can be improved, the viscosity can be reduced, and the mechanical properties of the material can be enhanced.

[0025] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present invention will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 The present invention is a flowchart of the steps of a method for preparing a high thermal conductivity and low viscosity silicone material. DETAILED DESCRIPTION

[0028] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0029] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0030] Embodiment 1

[0031] In the prior art, traditional silicone materials have the problems of poor thermal conductivity and high viscosity, making it difficult to meet the application requirements of high thermal conductivity and low viscosity.

[0032] To do this, see Figure 1 The embodiment of the present invention provides a high thermal conductivity and low viscosity silicone material, comprising the following components by mass: 60 parts of silicone matrix, 30 parts of thermal conductive filler, 5 parts of functional additive, 5 parts of auxiliary additive, 2 parts of polytetrafluoroethylene, and 5 parts of fluorocarbon solvent;

[0033] The silica gel matrix includes the following components in parts by mass: 30 parts of polydimethylsiloxane, 30 parts of polyethylene terephthalate, 20 parts of γ-trifluoropropylmethylpolysiloxane, 20 parts of a crosslinking agent, and 5 parts of a catalyst;

[0034] The thermal conductive filler includes the following components in parts by mass: 5 parts of carbon nanotubes, 3 parts of graphene, 3 parts of surfactant, 15 parts of aluminum oxide and 15 parts of boron nitride;

[0035] By adding a certain amount of polydimethylsiloxane, polyethylene terephthalate and γ-trifluoropropylmethylpolysiloxane to the silica gel matrix, since the above materials have the characteristics of high heat resistance, small adhesion change with temperature and good thermal conductivity, the purpose of reducing the viscosity of the silica gel material and improving the thermal conductivity effect can be achieved.

[0036] In Example 1, the functional additive includes the following components in parts by mass: 1 part of a leveling agent, 1 part of a coupling agent and 2 parts of a diluent, and the auxiliary additive includes the following components in parts by mass: 2 parts of a dye, 2 parts of an antibacterial agent and 1 part of an antifungal agent.

[0037] In Example 1, the crosslinking agent is an acrylic polymer, the surfactant is trimethylsilylamine, and polydimethylsiloxane, polyethylene terephthalate and γ-trifluoropropylmethylpolysiloxane are formed into a polymer compound by polymerization reaction of acrylic monomers, which can have good heat resistance, chemical resistance and physical properties.

[0038] In addition, the present invention also provides a method for preparing a high thermal conductivity and low viscosity silicone material, comprising the following steps:

[0039] Step 1: pre-treating the thermal conductive filler to form a paste-like mixture;

[0040] Step 2: pre-mixing the base material and uniformly dispersing the base material by ultrasonic dispersion;

[0041] Step 3: Add the thermal conductive filler, the base material and the functional additive into the mixer and mix them thoroughly;

[0042] Step 4: Take out the mixed material and put it into the mold to carry out vulcanization reaction to shape the silicone material;

[0043] Step 5: Heat treatment and surface treatment of the cured silicone material.

[0044] In Example 1, in step 1, carbon nanotubes, graphene, surfactant, aluminum oxide and boron nitride are added to a sample tank, clean water is added in an equal proportion to the surfactant, and the mixture is homogenized using a non-invasive material homogenizer to fully break up the filler particles to form a mixture, and the mixture forms a non-flowing paste.

[0045] In Example 1, in step 2, polydimethylsiloxane, polyethylene terephthalate and γ-trifluoropropylmethylpolysiloxane are put into an ultrasonic disperser for mixing and dispersion.

[0046] In Example 1, in step 3, the mixed raw materials are transferred to a degassing machine for decompression degassing treatment to remove bubbles generated during the mixing process. The degassing machine can be used to remove bubbles to improve product quality.

[0047] In Example 1, in step 5, polytetrafluoroethylene powder is dissolved in a fluorocarbon solvent to prepare a polytetrafluoroethylene solution, the polytetrafluoroethylene solution is evenly sprayed on the surface of the silicone material, and then the silicone material is heat-treated. After the heat treatment, the thermal conductivity, viscosity and mechanical strength of the silicone material are tested. After spraying, the polytetrafluoroethylene solution can form a non-sticky film on the surface of the silicone material, thereby effectively preventing adhesion between substances.

[0048] In order to solve the technical problems existing in the prior art, the present invention provides a high thermal conductivity and low viscosity silicone material, and solves the problem through the following technical solutions:

[0049] By selecting polydimethylsiloxane, polyethylene terephthalate and γ-trifluoropropylmethylpolysiloxane with excellent thermal stability and chemical stability as the matrix material, the molecular structure and cross-linking density of silica gel can be optimized to achieve the characteristics of low viscosity. By introducing carbon nanotubes, graphene, alumina and boron nitride with high thermal conductivity, the silica gel material can have a high thermal conductivity coefficient and excellent dispersibility, which can effectively improve the thermal conductivity of the silica gel material. By adding an appropriate amount of functional additives such as leveling agents and coupling agents, the dispersibility of thermal conductive fillers in the silica gel matrix can be improved, the viscosity can be reduced, and the mechanical properties of the material can be enhanced.

[0050] Embodiment 2

[0051] like Figure 1 As shown, an embodiment of the present invention provides a high thermal conductivity and low viscosity silicone material, including the following components by mass: 70 parts of silicone matrix, 40 parts of thermal conductive filler, 8 parts of functional additives, 8 parts of auxiliary additives, 3 parts of polytetrafluoroethylene, and 8 parts of fluorocarbon solvent;

[0052] The silica gel matrix includes the following components in parts by mass: 28 parts of polydimethylsiloxane, 25 parts of polyethylene terephthalate, 18 parts of γ-trifluoropropylmethylpolysiloxane, 15 parts of a crosslinking agent, and 4 parts of a catalyst;

[0053] The thermal conductive filler includes the following components in parts by mass: 10 parts of carbon nanotubes, 8 parts of graphene, 2 parts of surfactant, 10 parts of aluminum oxide and 11 parts of boron nitride;

[0054] By adding a certain amount of polydimethylsiloxane, polyethylene terephthalate and γ-trifluoropropylmethylpolysiloxane into the silica gel matrix, the above materials all have the characteristics of high heat resistance, small adhesion change with temperature and good thermal conductivity, thereby achieving the purpose of reducing viscosity and improving thermal conductivity;

[0055] Due to the unique physical and chemical properties of carbon nanotubes, graphene, alumina, and boron nitride, when used as raw materials, they can improve the thermal conductivity of silicone materials and reduce viscosity, while further improving the durability and stability of silicone materials. By adding alumina to silicone materials, not only can the thermal conductivity of the material be improved, but also the mechanical strength and wear resistance of the silicone material can be enhanced.

[0056] In Example 2, the functional additives include the following components in parts by mass: 3 parts of leveling agent, 2 parts of coupling agent and 2 parts of diluent, and the auxiliary additives include the following components in parts by mass: 1 part of dye, 2 parts of antibacterial agent and 1 part of mildewproof agent.

[0057] In Example 2, an acrylic polymer is used as a crosslinking agent, trisilylamine is used as a surfactant, and polydimethylsiloxane, polyethylene terephthalate and γ-trifluoropropylmethylpolysiloxane are formed into a polymer compound by polymerization reaction of acrylic monomers, which can have good weather resistance, chemical resistance and physical properties.

[0058] In addition, the present invention also provides a method for preparing a high thermal conductivity and low viscosity silicone material, comprising the following steps:

[0059] Step 1: pre-treating the thermal conductive filler to form a paste-like mixture;

[0060] Step 2: pre-mixing the base material and uniformly dispersing the base material by ultrasonic dispersion;

[0061] Step 3: Add the thermal conductive filler, the base material and the functional additive into the mixer and mix them thoroughly;

[0062] Step 4: Take out the mixed material and put it into the mold to carry out vulcanization reaction to shape the silicone material;

[0063] Step 5: Heat treatment and surface treatment of the cured silicone material.

[0064] In Example 2, in step 1, MXene is added to the thermal conductive filler, and a combination of MXene and boron nitride is prepared by chemical vapor deposition technology;

[0065] Chemical vapor deposition is a method of forming MXene materials by depositing metal atoms and carbon source atoms on a substrate at high temperature using chemical vapor deposition technology. The preparation process of this method mainly includes three steps: substrate surface treatment, chemical vapor deposition and post-processing. First, the substrate surface needs to be treated to improve the adhesion and stability of the MXene material. Secondly, the metal atoms and carbon source atoms are deposited on the substrate by chemical vapor deposition technology to form MXene materials. Finally, through the post-processing step, impurities and unreacted raw materials are removed to obtain pure MXene materials.

[0066] Using chemical modification methods to improve the wettability and compatibility of the carbon nanotube and boron nitride surfaces, and promote the close combination of carbon nanotubes and boron nitride;

[0067] For example: Fluorination treatment: fluorine atoms can be introduced into the surface of boron nitride through fluorination treatment to form fluorinated boron nitride. The introduction of fluorine atoms can change the electronic structure and chemical properties of the surface of boron nitride, thereby improving its wettability and compatibility.

[0068] By combining MXene with boron nitride, the thermal conductivity can be significantly improved while maintaining the insulating properties of the silicone material.

[0069] In Example 2, in step 3, the pretreated raw materials are placed in a mixer, auxiliary additives are added, and high-speed stirring and mixing are performed. During the mixing process, the operating temperature of the mixer is 300°C, the mixing time is 35 minutes, and the speed of the mixer is 250r / min. By mixing the raw materials in the mixer, a variety of raw materials can be polymerized to prepare a silicone material with high thermal conductivity and low viscosity.

[0070] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of various changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A high thermal conductivity and low viscosity silicone material, characterized in that: The invention comprises the following components by mass: 60-70 parts of silica gel matrix, 30-40 parts of thermal conductive filler, 5-8 parts of functional additive, 5-8 parts of auxiliary additive, 2-3 parts of polytetrafluoroethylene, and 5-10 parts of fluorocarbon solvent; The silica gel matrix comprises the following components in parts by mass: 25-30 parts of polydimethylsiloxane, 20-30 parts of polyethylene terephthalate, 15-20 parts of γ-trifluoropropylmethylpolysiloxane, 10-20 parts of a crosslinking agent and 2-5 parts of a catalyst; The thermal conductive filler comprises the following components in parts by mass: 5-15 parts of carbon nanotubes, 3-10 parts of graphene, 1-3 parts of surfactant, 5-15 parts of aluminum oxide and 5-15 parts of boron nitride.

2. The high thermal conductivity and low viscosity silicone material according to claim 1, characterized in that: The functional additives include the following components by mass: 1-3 parts of a leveling agent, 1-2 parts of a coupling agent and 1-2 parts of a diluent, and the auxiliary additives include the following components by mass: 1-2 parts of a dye, 1-2 parts of an antibacterial agent and 1-3 parts of an antifungal agent.

3. The high thermal conductivity and low viscosity silicone material according to claim 1, characterized in that: The cross-linking agent is an acrylic acid polymer, and the surfactant is trimethylsilylamine.

4. A method for preparing a high thermal conductivity and low viscosity silicone material, applied to a high thermal conductivity and low viscosity silicone material as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: pre-treating the thermal conductive filler to form a paste-like mixture; Step 2: pre-mixing the base material and uniformly dispersing the base material by ultrasonic dispersion; Step 3: Add the thermal conductive filler, the base material and the functional additive into the mixer and mix them thoroughly; Step 4: Take out the mixed material and put it into the mold to carry out vulcanization reaction to shape the silicone material; Step 5: Heat treatment and surface treatment of the cured silicone material.

5. The method for preparing a high thermal conductivity and low viscosity silicone material according to claim 4, characterized in that: In step one, carbon nanotubes, graphene, surfactants, aluminum oxide and boron nitride are added to a sample tank, clean water in an equal proportion to the surfactant is added, and the mixture is homogenized using a non-invasive material homogenizer to fully break up the filler particles to form a mixture, and the mixture forms a non-flowing paste.

6. The method for preparing a high thermal conductivity and low viscosity silicone material according to claim 4, characterized in that: In step 2, polydimethylsiloxane, polyethylene terephthalate and γ-trifluoropropylmethylpolysiloxane are put into an ultrasonic disperser for mixing and dispersion.

7. The method for preparing a high thermal conductivity and low viscosity silicone material according to claim 4, characterized in that: In step three, the mixed raw materials are transferred to a degassing machine for decompression degassing treatment to remove bubbles generated during the mixing process.

8. The method for preparing a high thermal conductivity and low viscosity silicone material according to claim 4, characterized in that: In step one, MXene is added to the thermal conductive filler, and the combination of MXene and boron nitride is prepared using chemical vapor deposition technology. The wettability and compatibility of the surfaces of carbon nanotubes and boron nitride are improved using chemical modification methods.

9. The method for preparing a high thermal conductivity and low viscosity silicone material according to claim 4, characterized in that: In step three, the pretreated raw materials are placed in a mixer, auxiliary additives are added, and high-speed stirring and mixing are performed. During the mixing process, the working temperature of the mixer is 200°C-350°C, the mixing time is 30-40 minutes, and the speed of the mixer is 200-300r / min.

10. The method for preparing a high thermal conductivity and low viscosity silicone material according to claim 4, characterized in that: In step five, polytetrafluoroethylene powder is dissolved in a fluorocarbon solvent to prepare a polytetrafluoroethylene solution, the polytetrafluoroethylene solution is evenly sprayed on the surface of the silicone material, and then the silicone material is heat treated. After the heat treatment, the thermal conductivity, viscosity and mechanical strength properties of the silicone material are tested.

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