A method for preparing a high thermal conductivity and high insulation aramid flexible film material

Abstract

The invention belongs to the technical field of aramid film preparation, and discloses a preparation method of a high-thermal-conductivity and high-insulation aramid flexible film material, comprising the synthesis, neutralization, mixing of stock solution and film forming of aramid polymer, using aramid polymer as an ultra-thin flexible insulating substrate, adding micro-nano hexagonal boron nitride and micro-nano mica to make a boron nitride high-thermal-conductivity and high-insulation aramid flexible film, which can effectively improve the heat dissipation efficiency of electronic components and reduce signal transmission delay by virtue of its high thermal conductivity and low dielectric constant and other characteristics; has excellent electrical insulation, chemical stability, and corona resistance, and ensures the normal operation and safety of electronic equipment; has high temperature resistance, oxidation resistance and other characteristics to extend the service life of the product without performance degradation; has an ultra-thin thickness of up to 5um or even thinner, and can meet the demand for insulating materials in small spaces of more miniaturized products; has the special performance of soft deformation, can be closely attached to the surfaces of different special-shaped products to provide all-round protection, and the performance at the bends remains normal.

Description

Technical Field

[0001] The invention belongs to the technical field of aramid film preparation, and in particular relates to a method for preparing a high-thermal-conductivity and high-insulation aramid flexible film material. Background Art

[0002] Aramid 1313 polymer, also known as poly(m-phenylene isophthalamide) fiber, is a polymer material with excellent properties of high temperature resistance, flame retardancy, insulation and chemical stability.

[0003] With the increasingly urgent demands for miniaturization, centralized functions, lightweight materials, safe operation, device weight reduction and thinning of products in the fields of aerospace, new energy, low-altitude economy, artificial intelligence, fly-by-wire power distribution, supercomputing and chip electronic applications, the corresponding high-end precision miniaturized electronic components, micro motors and chips must not only be smaller in size, but also generate greater power output to meet normal use under the above harsh conditions.

[0004] It has become a huge problem for existing tiny electronic components to solve the problems of rapid heat dissipation, insulation protection under high voltage, whether there are ultra-thin insulation materials to meet the needs of miniaturization, and the need for overall or local protection of special-shaped products without dead corners. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing a high thermal conductivity and high insulation aramid flexible film material to solve the problems of low thermal conductivity, weak electrical insulation and inability to meet the needs of miniaturization of existing micro electronic components.

[0006] In order to achieve the above object, the present invention provides the following technical solution: a method for preparing a high thermal conductivity and high insulation aramid flexible film material, comprising the following steps: Sp1: Synthesis of aramid polymer, dissolving m-phenylenediamine in amide polar organic solvent DMAC, controlling the reaction temperature to be below 0°C, adding a corresponding amount of 90-95wt% of isophthaloyl chloride to carry out low-temperature polycondensation reaction, and after 2 hours, adding the remaining corresponding amount of 5-10wt% of isophthaloyl chloride to continue the low-temperature polycondensation reaction to obtain a by-product of hydrogen chloride; Sp2: Neutralization of aramid polymer: by-product hydrogen chloride is neutralized with alkaline earth metal oxide, calcium hydroxide or ammonia, and the temperature of the neutralization reaction is controlled below 30°C to obtain aramid polymer; Sp3: Mixing stock solution, adding micro-nano hexagonal boron nitride and micro-nano mica into the aramid polymer and stirring and mixing them evenly to form aramid membrane stock solution; Sp4: Film forming, the aramid film stock solution is filtered and then subjected to high-temperature vacuum degassing, and the aramid flexible film material is prepared by a biaxial stretching film-making process. The coating method can be divided into an impregnation method, a casting method and a biaxial stretching method according to the different processes. In order to obtain better physical properties, electrical properties and thermal stability, the present invention uses a biaxial stretching method, combined with biaxial orientation, namely longitudinal positioning and transverse positioning. The longitudinal positioning is to perform single-point positioning of the film (solid content 15.0%-25.0 wt%) in the mechanical direction at a temperature of 30-300°C, and the transverse positioning is to preheat the film and perform transverse expansion positioning, film crystallization, thermal setting and curing, etc., to complete the production of the aramid flexible film material.

[0007] Preferably, the reaction temperature in Sp1 is controlled below 0°C.

[0008] Preferably, the neutralization reaction temperature in Sp2 is controlled below 30°C.

[0009] Preferably, the aramid membrane stock solution in the Sp4 is filtered through a 1-5 μm filter medium.

[0010] Preferably, the temperature range of vacuum degassing in Sp4 is set at 80-100°C.

[0011] Preferably, the vacuum-degassed aramid membrane stock solution in Sp4 is stored at 10-50°C.

[0012] Preferably, the micro-nano hexagonal boron nitride and micro-nano mica in the Sp3 are mixed and ground with a fine grinder and a solvent before use, and the particle size of the micro-nano hexagonal boron nitride and micro-nano mica is ground to 0.5-0.8 um.

[0013] The beneficial effects of the present invention are as follows: The present invention adopts aramid polymer as an ultra-thin flexible insulating substrate, and adds micro-nano hexagonal boron nitride and micro-nano mica to make a high thermal conductivity and high insulation aramid flexible film. With its high thermal conductivity and low dielectric constant, it can effectively improve the heat dissipation efficiency of electronic components and reduce signal transmission delay; it has excellent electrical insulation, chemical stability, and corona resistance to ensure the normal operation and safety of electronic equipment; it has high temperature resistance and oxidation resistance to extend the service life of the product without performance degradation; the ultra-thin thickness can reach 5um or even thinner, which can meet the demand for insulating materials in small spaces of more miniaturized products; it has the special property of soft deformation and can be tightly attached to the surfaces of different special-shaped products to provide all-round protection, and the performance at the bends remains normal. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a flow chart of the present invention; Figure 2The figure is a flow chart of the biaxial stretching film-making process of the present invention. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] Example: like Figure 1 to Figure 2 The embodiment of the present invention provides a method for preparing a high thermal conductivity and high insulation aramid flexible film material, comprising the following steps: Sp1: Synthesis of aramid polymer, dissolving m-phenylenediamine in amide polar organic solvent DMAC, controlling the reaction temperature to be below 0°C, adding a corresponding amount of 90-95wt% of isophthaloyl chloride to carry out low-temperature polycondensation reaction, and after 2 hours, adding the remaining corresponding amount of 5-10wt% of isophthaloyl chloride to continue the low-temperature polycondensation reaction to obtain a by-product of hydrogen chloride; Sp2: Neutralization of aramid polymer, by-product hydrogen chloride is neutralized with alkaline earth metal oxide, calcium hydroxide or ammonia, the temperature of the neutralization reaction is controlled below 30°C, to obtain aramid polymer, the concentration of aramid polymer is 15-25wt%, [η] is 1.7-2.5, and the pH value is 4-7; Sp3: Mixing stock solution, adding micro-nano hexagonal boron nitride and micro-nano mica to the aramid polymer, stirring and mixing them evenly to form the aramid membrane stock solution, the micro-nano hexagonal boron nitride and micro-nano mica are mixed and ground by a fine grinder and a solvent before use, the particle size of the micro-nano hexagonal boron nitride and micro-nano mica is ground to 0.5-0.8um, and the addition amount is basically controlled at 5-20wt% of the aramid polymer volume, the micro-nano mica and the micro-nano hexagonal boron nitride each account for half, and the proportion of the two can be adjusted according to the specific situation; Sp4: film forming, the aramid film stock solution is filtered through a 1-5μm filter medium and then vacuum degassed at high temperature. The temperature range of vacuum degassed is set at 80-100°C. The vacuum degassed aramid film stock solution is stored at 10-50°C. The biaxial stretching film making process is used to complete the preparation of the aramid flexible film material. The coating method can be divided into an impregnation method, a casting method and a biaxial stretching method according to the different processes. In order to obtain better physical properties, electrical properties and thermal stability, the present invention uses a biaxial stretching method, combined with biaxial orientation, namely longitudinal positioning and transverse positioning. The longitudinal positioning is to perform single-point positioning of the film (solid content 15.0%-25.0 wt%) in the mechanical direction at a temperature of 30-300°C. The transverse positioning is to preheat the film and then perform transverse expansion positioning, film crystallization, thermal setting and curing to complete the production of the aramid flexible film material.

[0017] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0018] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a high thermal conductivity and high insulation aramid flexible film material, characterized in that: The following steps are involved: Sp1: Synthesis of aramid polymer, dissolving m-phenylenediamine in amide polar organic solvent DMAC, adding a corresponding amount of 90-95wt% of isophthaloyl chloride to carry out low-temperature polycondensation reaction, and after 2 hours, adding the remaining corresponding amount of 5-10wt% of isophthaloyl chloride to continue the low-temperature polycondensation reaction to obtain a by-product of hydrogen chloride; Sp2: Neutralization of aramid polymer, by-product hydrogen chloride is neutralized with alkaline earth metal oxide, calcium hydroxide or ammonia to obtain aramid polymer; Sp3: Mixing stock solution, adding micro-nano hexagonal boron nitride and micro-nano mica into the aramid polymer and stirring and mixing them evenly to form aramid membrane stock solution; Sp4: Film forming: the aramid film stock solution is filtered and then subjected to high-temperature vacuum degassing, and the biaxial stretching film-making process is used to complete the preparation of the aramid flexible film material.

2. The method for preparing an aramid flexible film material according to claim 1, characterized in that: The reaction temperature in the Sp1 is controlled below 0°C.

3. The method for preparing an aramid flexible film material according to claim 1, characterized in that: The neutralization reaction temperature in the Sp2 is controlled below 30°C.

4. The method for preparing an aramid flexible film material according to claim 1, characterized in that: The aramid membrane stock solution in the Sp4 is filtered through a 1-5 μm filter medium.

5. The method for preparing an aramid flexible film material according to claim 1, characterized in that: The temperature range of vacuum degassing in the Sp4 is set at 80-100°C.

6. The method for preparing an aramid flexible film material according to claim 1, characterized in that: The vacuum degassed aramid membrane stock solution in the Sp4 is stored at 10-50°C.

7. The method for preparing an aramid flexible film material according to claim 1, characterized in that: The micro-nano hexagonal boron nitride and micro-nano mica in the Sp3 are mixed and ground with a fine grinder and a solvent before use, and the particle sizes of the micro-nano hexagonal boron nitride and micro-nano mica are ground to 0.5-0.8 um.

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