Filler dispersion process for improving thermal stability of organic silicon insulating material

Abstract

The invention relates to the field of filler dispersion processes, and discloses a filler dispersion process for improving the thermal stability of an organic silicon insulating material, which comprises the following steps: S1, filler screening and characterization: screening at least two high-temperature-resistant fillers from hexagonal boron nitride, muscovite and phlogopite based on the microscopic characteristics of the fillers, the type, the particle size, the morphology and the crystal structure of the filler are systematically characterized; s2, surface chemical modification: carrying out surface chemical modification on the screened filler, and enhancing the interface bonding force between the filler and an organic silicon matrix through coupling agent treatment or functional modification; s3, multi-component filler synergistic dispersion; s4, optimizing process parameters; and S5, forming the composite material. Compared with the prior art, the process has the advantages that through systematic filler screening, surface modification and dispersion process control, uniform dispersion and firm interface bonding of the filler in an organic silicon matrix are achieved, and therefore the thermal stability of the composite material is remarkably improved.

Description

Technical Field

[0001] This invention relates to filler dispersion processes. Specifically, it relates to a filler dispersion process for improving the thermal stability of organosilicon insulating materials. Background Technology

[0002] Organosilicon insulating materials are widely used in the field of electrical insulation due to their silicon-oxygen backbone structure and organic side groups. However, under long-term high-temperature service conditions, the material performance faces challenges: the siloxane backbone may degrade or rearrange, the organic side groups are easily oxidized, and microcracks or even debonding may easily occur between the filler and the organosilicon matrix due to differences in thermal expansion coefficients or weakened interfacial bonding, leading to a decline in the material's mechanical and electrical insulation properties and increasing the risk of electrical equipment failure.

[0003] In existing technologies, the thermal stability of organosilicon materials is often improved by adding inorganic fillers. However, conventional methods often focus on simple physical blending of fillers or limited modifications to existing organosilicon systems. These methods often fail to systematically consider the microscopic properties of the fillers (such as crystal structure and morphology) and their interfacial interactions with the matrix, resulting in uneven dispersion of fillers in the matrix, weak interfacial bonding, and difficulty in fully realizing the heat resistance potential of the fillers. Especially when used for long-term applications at temperatures of 250°C and above, the improvement in thermal stability is limited, and the material lifespan is insufficient to meet the requirements of high-end applications. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] The technical problem to be solved by the present invention is to provide a filler dispersion process for improving the thermal stability of organosilicon insulating materials. This process aims to achieve uniform dispersion and strong interfacial bonding of fillers in organosilicon matrix through systematic filler screening, surface modification and dispersion process control, thereby significantly improving the thermal stability of composite materials.

[0006] (II) Technical Solution

[0007] To solve the above-mentioned technical problems, the technical solution provided by the present invention is: a filler dispersion process for improving the thermal stability of organosilicon insulating materials, comprising the following steps:

[0008] S1. Filler screening and characterization: Based on the microscopic characteristics of the fillers, at least two high-temperature resistant fillers were screened from hexagonal boron nitride, muscovite, and phlogopite, and the type, particle size, morphology and crystal structure of the fillers were systematically characterized.

[0009] S2. Surface chemical modification: The selected fillers are subjected to surface chemical modification. The interfacial bonding force between the fillers and the organosilicon matrix is ​​enhanced by coupling agent treatment or functional modification, which inhibits microcracks and debonding caused by the mismatch of thermal expansion coefficients.

[0010] S3. Synergistic dispersion of multi-component fillers: The surface-modified fillers are mixed with the organosilicon matrix in an optimized ratio, and a uniform multi-component composite filler system is constructed by combining mechanical stirring and ultrasonic dispersion.

[0011] S4. Optimization of process parameters: Single-factor experimental method, orthogonal experimental design and response surface analysis were used to optimize the process parameters of filler addition amount, dispersion time, temperature and shear rate to ensure that the filler is uniformly dispersed in the matrix and the interface bonding is stable.

[0012] S5. Composite material molding: The dispersed mixture is processed into high-temperature resistant organosilicon insulating material by hot pressing or injection molding, so that its 5% thermal weight loss temperature is not less than 400℃ in a nitrogen atmosphere and it can be used stably for a long time in an environment of 250℃.

[0013] As an improvement, in step S1, the particle size of the filler ranges from 0.5 μm to 50 μm, and its crystal structure is characterized by X-ray diffraction, while its morphology is observed by scanning electron microscopy.

[0014] As an improvement, the multi-component composite filler system is composed of hexagonal boron nitride and phlogopite, wherein the mass ratio of hexagonal boron nitride to phlogopite is 1:0.5 to 1:2.

[0015] As an improvement, in step S2, the coupling agent used for the surface chemical modification is a silane coupling agent, specifically γ-aminopropyltriethoxysilane or γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0016] As an improvement, in step S2, the surface chemical modification further includes a step of composite modification using succinic acid and a coupling agent.

[0017] As an improvement, in step S3, the mechanical stirring speed is 300 to 800 rpm and the stirring time is 30 to 90 minutes; the ultrasonic dispersion power is 500 to 1500 watts and the dispersion time is 20 to 60 minutes.

[0018] As an improvement, in step S4, the process parameters optimized by the response surface methodology include: the total amount of filler added is 20% to 60% of the mass of the silicone matrix, and the dispersion temperature is controlled at 50°C to 80°C.

[0019] As an improvement, after step S3, a step of characterizing the dispersion uniformity is also included, specifically: taking a small amount of the mixture sample and observing the dispersion state and interfacial bonding of the filler in the organosilicon matrix using a scanning electron microscope or a transmission electron microscope.

[0020] As an improvement, in step S5, the pressure of the hot pressing is 5 to 20 MPa, the temperature is 150 to 200°C, and the molding time is 10 to 30 minutes.

[0021] (III) Beneficial Effects

[0022] The advantages of this invention compared to the prior art are:

[0023] (1) By systematically screening and characterizing specific high-temperature resistant fillers and combining their microscopic properties to form a multi-component compound, a foundation is provided for constructing a stable composite material system.

[0024] (2) Surface chemical modification treatment enhances the interfacial compatibility and bonding force between the filler and the organosilicon matrix, which helps to alleviate the internal stress caused by the mismatch of thermal expansion coefficients and reduce the generation of microcracks at high temperatures.

[0025] (3) The synergistic effect of mechanical stirring and ultrasonic dispersion, combined with the optimized process parameters through experimental design, promotes the uniform distribution of fillers in the matrix and reduces performance defects caused by agglomeration. Detailed Implementation

[0026] The invention will now be described in further detail with reference to specific embodiments, but this should not be construed as limiting the scope of the subject matter of the invention to the following embodiments.

[0027] Example 1

[0028] A filler dispersion process for improving the thermal stability of organosilicon insulating materials, characterized in that:

[0029] Includes the following steps:

[0030] S1. Filler screening and characterization: Based on the microscopic characteristics of the fillers, at least two high-temperature resistant fillers were screened from hexagonal boron nitride, muscovite, and phlogopite. The type, particle size, morphology, and crystal structure of the fillers were systematically characterized. The particle size range of the fillers was 0.5 μm, and their crystal structure was characterized by X-ray diffraction, and their morphology was observed by scanning electron microscopy.

[0031] S2. Surface chemical modification: The selected filler is subjected to surface chemical modification. The interfacial bonding force between the filler and the organosilicon matrix is ​​enhanced by coupling agent treatment or functional modification, and microcracks and debonding caused by the mismatch of thermal expansion coefficients are suppressed. The coupling agent used in the surface chemical modification is a silane coupling agent, specifically γ-aminopropyltriethoxysilane. The surface chemical modification also includes a step of composite modification with succinic acid and coupling agent.

[0032] S3. Synergistic Dispersion of Multi-component Fillers: The surface-modified fillers are mixed with the organosilicon matrix in an optimized ratio. A uniform multi-component composite filler system is constructed by combining mechanical stirring and ultrasonic dispersion. The multi-component composite filler system consists of hexagonal boron nitride and phlogopite, wherein the mass ratio of hexagonal boron nitride to phlogopite is 1:0.5. The mechanical stirring speed is 300 rpm and the stirring time is 30 minutes. The ultrasonic dispersion power is 500 watts and the dispersion time is 20 minutes. The method also includes a step to characterize the dispersion uniformity, specifically: taking a small amount of the mixture sample and observing the dispersion state and interfacial bonding of the fillers in the organosilicon matrix using a scanning electron microscope or a transmission electron microscope.

[0033] S4. Optimization of process parameters: Single-factor experimental method, orthogonal experimental design and response surface analysis method are used to optimize the process parameters of filler addition amount, dispersion time, temperature and shear rate to ensure that the filler is uniformly dispersed in the matrix and the interface bonding is stable. The process parameters optimized by the response surface analysis method include: the total amount of filler added is 20% of the mass of the organosilicon matrix, and the dispersion temperature is controlled at 50℃.

[0034] S5. Composite material molding: The dispersed mixture is processed into a high-temperature resistant organosilicon insulating material by hot pressing or injection molding, so that its 5% thermal weight loss temperature is not lower than 400℃ under a nitrogen atmosphere and it can be used stably for a long time at 250℃. The hot pressing pressure is 5MPa, the temperature is 150℃, and the molding time is 10 minutes.

[0035] Example 2

[0036] S1. Filler screening and characterization: Based on the microscopic characteristics of the fillers, at least two high-temperature resistant fillers were screened from hexagonal boron nitride, muscovite, and phlogopite. The type, particle size, morphology and crystal structure of the fillers were systematically characterized. The particle size range of the fillers was 20 μm, and their crystal structure was characterized by X-ray diffraction and their morphology was observed by scanning electron microscopy.

[0037] S2. Surface chemical modification: The selected filler is subjected to surface chemical modification. The interfacial bonding force between the filler and the organosilicon matrix is ​​enhanced by coupling agent treatment or functional modification, and microcracks and debonding caused by the mismatch of thermal expansion coefficients are suppressed. The coupling agent used in the surface chemical modification is a silane coupling agent, specifically γ-(2,3-epoxypropoxy)propyltrimethoxysilane. The surface chemical modification also includes a step of composite modification with succinic acid and coupling agent.

[0038] S3. Synergistic Dispersion of Multi-component Fillers: The surface-modified fillers are mixed with the organosilicon matrix in an optimized ratio. A uniform multi-component composite filler system is constructed by combining mechanical stirring and ultrasonic dispersion. The multi-component composite filler system consists of hexagonal boron nitride and phlogopite, wherein the mass ratio of hexagonal boron nitride to phlogopite is 1:1. The mechanical stirring speed is 500 rpm and the stirring time is 60 minutes. The ultrasonic dispersion power is 1000 watts and the dispersion time is 40 minutes. The method also includes a step to characterize the dispersion uniformity, specifically: taking a small amount of the mixture sample and observing the dispersion state and interfacial bonding of the fillers in the organosilicon matrix using a scanning electron microscope or a transmission electron microscope.

[0039] S4. Optimization of process parameters: Single-factor experimental method, orthogonal experimental design and response surface analysis method are used to optimize the process parameters of filler addition amount, dispersion time, temperature and shear rate to ensure that the filler is uniformly dispersed in the matrix and the interface bonding is stable. The process parameters optimized by the response surface analysis method include: the total amount of filler added is 40% of the mass of the organosilicon matrix, and the dispersion temperature is controlled at 60℃.

[0040] S5. Composite material molding: The dispersed mixture is processed into a high-temperature resistant organosilicon insulating material by hot pressing or injection molding, so that its 5% thermal weight loss temperature is not lower than 400℃ in a nitrogen atmosphere and it can be used stably for a long time in an environment of 250℃. The hot pressing pressure is 10MPa, the temperature is 180℃, and the molding time is 20 minutes.

[0041] Example 3

[0042] S1. Filler screening and characterization: Based on the microscopic characteristics of the fillers, at least two high-temperature resistant fillers were screened from hexagonal boron nitride, muscovite, and phlogopite. The type, particle size, morphology and crystal structure of the fillers were systematically characterized. The particle size range of the fillers was 50 μm, and their crystal structure was characterized by X-ray diffraction and their morphology was observed by scanning electron microscopy.

[0043] S2. Surface chemical modification: The selected filler is subjected to surface chemical modification. The interfacial bonding force between the filler and the organosilicon matrix is ​​enhanced by coupling agent treatment or functional modification, and microcracks and debonding caused by the mismatch of thermal expansion coefficients are suppressed. The coupling agent used in the surface chemical modification is a silane coupling agent, specifically γ-aminopropyltriethoxysilane. The surface chemical modification also includes a step of composite modification with succinic acid and coupling agent.

[0044] S3. Synergistic Dispersion of Multi-component Fillers: The surface-modified fillers are mixed with the organosilicon matrix in an optimized ratio. A uniform multi-component composite filler system is constructed by combining mechanical stirring and ultrasonic dispersion. The multi-component composite filler system consists of hexagonal boron nitride and phlogopite, wherein the mass ratio of hexagonal boron nitride to phlogopite is 1:2. The mechanical stirring speed is 800 rpm and the stirring time is 90 minutes. The ultrasonic dispersion power is 1500 watts and the dispersion time is 60 minutes. The method also includes a step to characterize the dispersion uniformity, specifically: taking a small amount of the mixture sample and observing the dispersion state and interfacial bonding of the fillers in the organosilicon matrix using a scanning electron microscope or a transmission electron microscope.

[0045] S4. Optimization of process parameters: Single-factor experimental method, orthogonal experimental design and response surface analysis method are used to optimize the process parameters of filler addition amount, dispersion time, temperature and shear rate to ensure that the filler is uniformly dispersed in the matrix and the interface bonding is stable. The process parameters optimized by the response surface analysis method include: the total amount of filler added is 60% of the mass of the organosilicon matrix, and the dispersion temperature is controlled at 80℃.

[0046] S5. Composite material molding: The dispersed mixture is processed into a high-temperature resistant organosilicon insulating material by hot pressing or injection molding, so that its 5% thermal weight loss temperature is not lower than 400℃ under a nitrogen atmosphere and it can be used stably for a long time at 250℃. The hot pressing pressure is 20MPa, the temperature is 200℃, and the molding time is 30 minutes.

[0047] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents. In short, if those skilled in the art are inspired by these claims and design similar structural methods and embodiments without departing from the inventive spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A filler dispersion process for improving the thermal stability of organosilicon insulating materials, characterized in that: Includes the following steps: S1. Filler screening and characterization: Based on the microscopic characteristics of the fillers, at least two high-temperature resistant fillers were screened from hexagonal boron nitride, muscovite, and phlogopite, and the type, particle size, morphology and crystal structure of the fillers were systematically characterized. S2. Surface chemical modification: The selected fillers are subjected to surface chemical modification. The interfacial bonding force between the fillers and the organosilicon matrix is ​​enhanced by coupling agent treatment or functional modification, which inhibits microcracks and debonding caused by the mismatch of thermal expansion coefficients. S3. Synergistic dispersion of multi-component fillers: The surface-modified fillers are mixed with the organosilicon matrix in an optimized ratio, and a uniform multi-component composite filler system is constructed by combining mechanical stirring and ultrasonic dispersion. S4. Optimization of process parameters: Single-factor experimental method, orthogonal experimental design and response surface analysis were used to optimize the process parameters of filler addition amount, dispersion time, temperature and shear rate to ensure that the filler is uniformly dispersed in the matrix and the interface bonding is stable. S5. Composite material molding: The dispersed mixture is processed into high-temperature resistant organosilicon insulating material by hot pressing or injection molding, so that its 5% thermal weight loss temperature is not less than 400℃ in a nitrogen atmosphere and it can be used stably for a long time in an environment of 250℃.

2. The filler dispersion process for improving the thermal stability of organosilicon insulating materials according to claim 1, characterized in that: In step S1, the particle size of the filler ranges from 0.5 μm to 50 μm, and its crystal structure is characterized by X-ray diffraction, while its morphology is observed by scanning electron microscopy.

3. The filler dispersion process for improving the thermal stability of organosilicon insulating materials according to claim 1 or 2, characterized in that: The multi-component composite filler system is composed of hexagonal boron nitride and phlogopite, wherein the mass ratio of hexagonal boron nitride to phlogopite is 1:0.5 to 1:

2.

4. The filler dispersion process for improving the thermal stability of organosilicon insulating materials according to claim 1, characterized in that: In step S2, the coupling agent used for the surface chemical modification is a silane coupling agent, specifically γ-aminopropyltriethoxysilane or γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

5. The filler dispersion process for improving the thermal stability of organosilicon insulating materials according to claim 1, characterized in that: In step S2, the surface chemical modification further includes a step of composite modification using succinic acid and a coupling agent.

6. The filler dispersion process for improving the thermal stability of organosilicon insulating materials according to claim 1, characterized in that: In step S3, the mechanical stirring speed is 300 to 800 rpm and the stirring time is 30 to 90 minutes; the ultrasonic dispersion power is 500 to 1500 watts and the dispersion time is 20 to 60 minutes.

7. The filler dispersion process for improving the thermal stability of organosilicon insulating materials according to claim 1, characterized in that: In step S4, the process parameters optimized by the response surface methodology include: the total amount of filler added is 20% to 60% of the mass of the silicone matrix, and the dispersion temperature is controlled at 50°C to 80°C.

8. The filler dispersion process for improving the thermal stability of organosilicon insulating materials according to claim 1, characterized in that: After step S3, a step of characterizing the dispersion uniformity is also included, specifically: taking a small amount of the mixture sample and observing the dispersion state and interfacial bonding of the filler in the organosilicon matrix using a scanning electron microscope or a transmission electron microscope.

9. The filler dispersion process for improving the thermal stability of organosilicon insulating materials according to claim 1, characterized in that: In step S5, the hot pressing pressure is 5 to 20 MPa, the temperature is 150 to 200°C, and the molding time is 10 to 30 minutes.