Halogen-free flame-retardant silicone heat-conducting pouring sealant base and preparation method thereof

Abstract

The application provides a halogen-free flame-retardant silicone heat-conducting pouring sealant base material, which comprises the following components in proportion by weight: 100 parts of vinyl silicone oil, 400-600 parts of first silica powder, 100-300 parts of second silica powder, 100-300 parts of first aluminum hydroxide powder, 200-400 parts of first aluminum oxide powder and 1-20 parts of surface treatment agent, the particle size of the first silica powder is 50-70 mu m, the particle size of the second silica powder is 7-10 mu m, the particle size of the first aluminum hydroxide powder is 7-10 mu m, and the particle size of the first aluminum oxide powder is 2-3 mu m. The halogen-free flame-retardant silicone heat-conducting pouring sealant base material has the advantages of high filling amount, a halogen-free flame-retardant system, high filling, low viscosity, good fluidity, low specific gravity after dilution of the base material, material lightening, and energy saving and consumption reduction.

Description

Technical Field

[0001] This invention relates to the field of potting compound technology, specifically to a halogen-free flame-retardant silicone thermally conductive potting compound base material and its preparation method. Background Technology

[0002] Electronic devices are prone to overheating during operation, and poor heat dissipation can damage device performance and shorten equipment lifespan. Thermally conductive materials can effectively dissipate heat and improve the reliability of equipment. Silicone materials possess advantages such as temperature resistance, insulation, and flexibility, making them suitable for harsh application scenarios. They are an excellent base material for thermally conductive potting compounds. The base material of thermally conductive potting compounds is the core carrier, directly determining the filler dispersion effect and the quality of the thermal conductive pathway formation. Base material refining is also crucial for formulation development, as its quality affects various product performance aspects. Existing traditional thermally conductive potting compounds have the following drawbacks: First, the material has a relatively high specific gravity, which increases the energy consumption of equipment such as automobiles, while lightweighting is an important development direction for energy conservation and environmental protection. Second, the flame retardancy is insufficient, posing a fire and explosion hazard. Third, the filler loading is limited, resulting in high transportation and storage costs. High filler loading leads to loss of fluidity in the base material, resulting in high viscosity and poor flowability, making it difficult to fill complex structures, tiny gaps, or gaps between densely packed components. Additionally, the material is prone to stratification and sedimentation, resulting in poor storage and transportation stability, and requiring specialized equipment and professional personnel for rubber refining production. Summary of the Invention

[0003] The purpose of this invention is to provide a halogen-free flame-retardant silicone thermally conductive potting compound to solve the technical problems in the background art.

[0004] To achieve the aforementioned objectives, the present invention provides the following technical solution:

[0005] A halogen-free flame-retardant silicone thermally conductive potting compound base material comprises the following components in the following weight proportions: 100 parts vinyl silicone oil, 400-600 parts No. 1 silica powder, 100-300 parts No. 2 silica powder, 100-300 parts No. 1 aluminum hydroxide powder, 200-400 parts No. 1 alumina powder, and 1-20 parts surface treatment agent. The particle size of the No. 1 silica powder is 50-70 μm, the particle size of the No. 2 silica powder is 7-10 μm, the particle size of the No. 1 aluminum hydroxide powder is 7-10 μm, and the particle size of the No. 1 alumina powder is 2-3 μm.

[0006] The viscosity of the vinyl silicone oil is 50 mPa·s.

[0007] The surface treatment agent is any one of a silane coupling agent, a titanate coupling agent, or an aluminate coupling agent.

[0008] A method for preparing a halogen-free flame-retardant organosilicon thermally conductive potting compound includes the following steps:

[0009] S1. Add No. 1 silica powder, No. 2 silica powder, No. 1 aluminum hydroxide powder and No. 1 alumina powder to a high-speed mixer and stir for 1-5 minutes at a frequency of 20-40HZ / MIN to obtain powder filler A.

[0010] S2. The surface treatment agent is uniformly added into the powder filler A, and stirred in a high-speed mixer for 3-8 minutes at a frequency of 20-40HZ / MIN to obtain the dry modified powder filler B.

[0011] S3. Place 50cp vinyl silicone oil and modified powder filler B into a kneader at a ratio of 100:1300 and knead at a speed of 10-30Hz. Heat to 80-120℃, vacuum degree 0.05-0.1MPa, and knead for 90-120 minutes to obtain a uniform thermally conductive potting compound base.

[0012] The thermally conductive potting compound base material is diluted with vinyl silicone oil, and then hydrogen-containing silicone oil, platinum catalyst, inhibitor, and color paste are directly added to complete the potting compound formulation. The production time is ≤20 min.

[0013] Compared with existing technologies, the halogen-free flame-retardant silicone thermally conductive potting compound of this application has a high filling capacity. It adopts a halogen-free flame-retardant system to achieve high filling capacity, low viscosity, and good flowability. The specific gravity of the base material is even lower after thinning, realizing material lightweighting and meeting the requirements of energy conservation and consumption reduction. Through the base material refining, the filler and silicone oil form a stable system. Combined with the weather-resistant and moisture-proof properties of silicone itself, it effectively solves the problems of sedimentation and deterioration of filler during storage and transportation. In addition, the client only needs to use vinyl silicone oil to thin and add small materials such as hydrogen-containing silicone oil, platinum catalyst, inhibitor, and color paste to complete the production. No special equipment or professional personnel are required, which significantly reduces the production threshold and improves production efficiency. Attached Figure Description

[0014] none. Detailed Implementation

[0015] The technical solutions in the embodiments of the present invention will be clearly and completely described below.

[0016] Specific Embodiment 1: In this embodiment of the invention, a halogen-free flame-retardant organosilicon thermally conductive potting compound base material comprises the following components by weight ratio: 100 parts of vinyl silicone oil, 400-600 parts of No. 1 silica powder, 100-300 parts of No. 2 silica powder, 100-300 parts of No. 1 aluminum hydroxide powder, 200-400 parts of No. 1 alumina powder, and 1-20 parts of surface treatment agent. The particle size of No. 1 silica powder is 50-70 μm, the particle size of No. 2 silica powder is 7-10 μm, the particle size of No. 1 aluminum hydroxide powder is 7-10 μm, and the particle size of No. 1 alumina powder is 2-3 μm. The viscosity of the vinyl silicone oil is 50 mPa·s, and the surface treatment agent is any one of a silane coupling agent, a titanate coupling agent, or an aluminate coupling agent.

[0017] A method for preparing a halogen-free flame-retardant organosilicon thermally conductive potting compound includes the following processing steps:

[0018] S1. Add No. 1 silica powder, No. 2 silica powder, No. 1 aluminum hydroxide powder and No. 1 alumina powder to a high-speed mixer and stir for 1-5 minutes at a frequency of 20-40HZ / MIN to obtain powder filler A.

[0019] S2. The surface treatment agent is uniformly added into the powder filler A, and stirred in a high-speed mixer for 3-8 minutes at a frequency of 20-40HZ / MIN to obtain the dry modified powder filler B.

[0020] S3. Place 50cp vinyl silicone oil and modified powder filler B into a kneader at a ratio of 100:1300 and knead at a speed of 10-30Hz. Heat to 80-120℃, vacuum degree 0.05-0.1MPa, and knead for 90-120 minutes to obtain a uniform thermally conductive potting compound base.

[0021] The prepared potting compound base was tested for relevant performance according to industry-standard parameters. The results and actual values ​​are shown in the table below.

[0022]

[0023] The test results show that the thermal conductivity of the potting compound prepared by this invention can reach 1.45 W / m·K, meeting the requirements for high thermal conductivity applications; the product viscosity is within a reasonable process range, suitable for automated potting operations; the flame retardant rating consistently reaches UL94V0, possessing excellent halogen-free flame retardant safety performance; the product specific gravity is only 2.09, significantly lower than the standard range of conventional products, effectively achieving material lightweighting, reducing the overall energy consumption of electronic and automotive equipment, and combining the multiple advantages of high thermal conductivity, low viscosity, high flame retardancy, and lightweighting. This thermally conductive potting compound can be diluted with vinyl silicone oil, and then directly mixed with hydrogen-containing silicone oil, platinum catalyst, inhibitor, and color paste to complete the potting compound formulation. The overall production time is ≤20 min, effectively simplifying the downstream production process.

[0024] Experiment on the effect of vinyl silicone oil thinning ratio on the properties of the base material: Maintaining 100 parts of the base material of this invention, vinyl silicone oil with a viscosity of 100 cp was selected as the thinning agent. By changing the amount of vinyl silicone oil added, the effects of different addition amounts on the viscosity, thermal conductivity, and flowability of the compound were investigated. Specific experimental data are as follows:

[0025]

[0026] Experimental conclusions: Under the premise of fixed base material dosage, as the amount of 100cp vinyl silicone oil added increases, the overall viscosity of the adhesive gradually decreases and the flow and leveling performance continues to improve. However, the proportion of thermally conductive filler in the system decreases relatively, resulting in a slight decrease in thermal conductivity. Taking into account both thermal conductivity and application flowability, the preferred amount of vinyl silicone oil added in this invention is 12 parts, which achieves the best balance between thermal conductivity and application viscosity.

[0027] Comparative experiment between the system of this invention and the traditional pure alumina system: A traditional pure alumina system with the same powder particle size distribution was selected as the comparative example. After refining the base materials, vinyl silicone oil was added to dilute the powder to an oil-to-powder ratio of 1:5 for performance testing. The specific experimental data are as follows:

[0028]

[0029] To verify the stability of the base material during long-distance transportation and long-term storage, a simulated transportation vibration experiment was set up: the sample was placed on a vibration platform and continuously vibrated at a fixed frequency of 50 Hz for 72 hours. After standing, the sedimentation stratification, precipitation hardness, and thixotropic recovery properties of the sample were observed. The specific test results are as follows:

[0030]

[0031] Experimental conclusion: This invention solves the problems of filler sedimentation and stratification through base material refining and powder surface modification. The product has excellent anti-vibration and anti-settling capabilities, which can meet the needs of long-distance logistics transportation and long-term ambient temperature storage. The batch stability and product consistency are far superior to the traditional pure alumina system, which meets the needs of industrial storage and off-site supply, and is suitable for industrial mass production and market promotion and application.

[0032] Compared with existing technologies, the halogen-free flame-retardant silicone thermally conductive potting compound of this application has a high filling capacity. It adopts a halogen-free flame-retardant system to achieve high filling capacity, low viscosity, and good flowability. The specific gravity of the base material is even lower after thinning, realizing material lightweighting and meeting the requirements of energy conservation and consumption reduction. Through the base material refining, the filler and silicone oil form a stable system. Combined with the weather-resistant and moisture-proof properties of silicone itself, it effectively solves the problems of sedimentation and deterioration of filler during storage and transportation. In addition, the client only needs to use vinyl silicone oil to thin and add small materials such as hydrogen-containing silicone oil, platinum catalyst, inhibitor, and color paste to complete the production. No special equipment or professional personnel are required, which significantly reduces the production threshold and improves production efficiency.

[0033] It will be apparent to those skilled in the art that the present invention is not limited to the details of the foregoing exemplary embodiments, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description; thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention.

[0034] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A halogen-free flame-retardant silicone thermally conductive potting compound, characterized in that: It comprises the following components by weight: 100 parts vinyl silicone oil, 400-600 parts No. 1 silica powder, 100-300 parts No. 2 silica powder, 100-300 parts No. 1 aluminum hydroxide powder, 200-400 parts No. 1 alumina powder, and 1-20 parts surface treatment agent. The particle size of the No. 1 silica powder is 50-70 μm, the particle size of the No. 2 silica powder is 7-10 μm, the particle size of the No. 1 aluminum hydroxide powder is 7-10 μm, and the particle size of the No. 1 alumina powder is 2-3 μm.

2. The halogen-free flame-retardant organosilicon thermally conductive potting compound according to claim 1, characterized in that: The viscosity of the vinyl silicone oil is 50 mPa·s.

3. The halogen-free flame-retardant organosilicon thermally conductive potting compound according to claim 2, characterized in that: The surface treatment agent is any one of a silane coupling agent, a titanate coupling agent, or an aluminate coupling agent.

4. A halogen-free flame-retardant organosilicon thermally conductive potting compound according to any one of claims 2-3, characterized in that: Its preparation method includes the following steps: S1. Add No. 1 silica powder, No. 2 silica powder, No. 1 aluminum hydroxide powder and No. 1 alumina powder to a high-speed mixer and stir for 1-5 minutes at a frequency of 20-40HZ / MIN to obtain powder filler A. S2. The surface treatment agent is uniformly added into the powder filler A, and stirred in a high-speed mixer for 3-8 minutes at a frequency of 20-40HZ / MIN to obtain the dry modified powder filler B. S3. Place 50cp vinyl silicone oil and modified powder filler B into a kneader at a ratio of 100:1300 and knead at a speed of 10-30Hz. Heat to 80-120℃, vacuum degree 0.05-0.1MPa, and knead for 90-120 minutes to obtain a uniform thermally conductive potting compound base.

5. The preparation method of a halogen-free flame-retardant organosilicon thermally conductive potting compound according to claim 4, characterized in that: The thermally conductive potting compound base material is diluted with vinyl silicone oil, and then hydrogen-containing silicone oil, platinum catalyst, inhibitor, and color paste are directly added to complete the potting compound formulation. The production time is ≤20 min.

Images