Two-component heat-conducting insulating EMI (Electro-Magnetic Interference) shielding material and preparation method thereof

Abstract

The invention discloses a two-component heat-conducting insulating EMI shielding material and a preparation method thereof, and relates to the technical field of EMI electromagnetic shielding materials. The two-component heat-conducting insulating EMI shielding material can effectively conduct heat generated by electronic equipment out, so that the equipment is prevented from being overheated, the safety of the equipment is improved, and the service life of the equipment is prolonged; meanwhile, the insulating property is excellent, internal elements and circuits can be effectively isolated, the electrical stability is improved, and normal operation of equipment is ensured; high shielding effectiveness can be achieved within the range of 20M-20GHz, the influence of electromagnetic radiation on equipment and the surrounding environment is effectively reduced, and the equipment is protected from external electromagnetic interference; the composite material can be applied to multiple fields such as consumer electronics, communication equipment, medical equipment, aerospace, military affairs, unmanned driving and electric automobiles, and meets the requirements of different industries for heat conduction, insulation and EMI shielding; the potting adhesive is low in viscosity and good in fluidity, can be easily processed into various shapes and sizes, and is suitable for potting and shielding requirements of different equipment.

Description

Technical Field

[0001] The invention belongs to the technical field of EMI electromagnetic shielding materials, and in particular relates to a two-component thermally conductive insulating EMI shielding material and a preparation method thereof. Background Art

[0002] As electronic devices are rapidly developing towards high integration and high frequency, electromagnetic interference (EMI) problems between electronic components have emerged. The rapid dissipation of accumulated heat and effective electromagnetic interference (EMI) shielding have attracted widespread attention. Giving thermal management materials EMI shielding properties is an effective way to overcome both heat dissipation and EMI problems. Existing metal or non-metallic conductive powders have high thermal conductivity and excellent electrical properties, and are suitable for the preparation of EMI shielding thermal management materials. By establishing a continuous conductive and thermal conductive network, excellent EMI shielding performance and high thermal conductivity can be obtained. However, existing conductive fillers will inevitably affect the electrical insulation performance, resulting in short circuits in electrical structures such as circuits.

[0003] In order to solve the above problems, researchers have tried to introduce insulating coatings on the surface of thermally conductive shielding materials, or to prepare electrically insulating EMI shielding thermal management materials by multi-layer composites with thermally conductive insulating materials. These methods can effectively improve the electrical insulation properties of EMI shielding materials and maintain their shielding properties.

[0004] The existing EMI shielding materials have problems of insufficient thermal conductivity and electromagnetic shielding performance because the thermal conductive powder cannot be added in large quantities. Therefore, a two-component thermal conductive insulating EMI shielding material and a preparation method thereof are proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a two-component thermally conductive insulating EMI shielding material and a preparation method thereof to solve the existing problems.

[0006] In order to solve the above technical problems, the present invention is achieved through the following technical solutions:

[0007] The present invention is a method for preparing a two-component thermally conductive insulating EMI shielding material, comprising the following steps:

[0008] S1. Depositing an insulating layer on the surface of a metal powder by plasma vapor phase chemical deposition to obtain an insulating metal powder, and then modifying the insulating metal powder with a vinyl silane coupling agent to obtain modified insulating metal powders with different particle sizes;

[0009] S2. Under vacuum conditions, component A is prepared from 4-40 parts by weight of single-end vinyl-containing polysiloxane, 60-90 parts of modified insulating metal powders of different particle sizes, and 0.06-1 parts of a catalyst as raw materials;

[0010] S3. Under vacuum conditions, component B is prepared from 2-30 parts by weight of single-end vinyl polysiloxane, 60-90 parts of modified insulating metal powders of different particle sizes, 0.5-5 parts of side chain hydrogen-containing polysiloxane, 1-10 parts of single-end hydrogen-containing polysiloxane and 0.0006-0.015 parts of inhibitor as raw materials;

[0011] S4. Mix component A and component B in a mass ratio of 1:1 and react to obtain the two-component thermally conductive insulating EMI shielding material.

[0012] Furthermore, the method for modifying the insulating metal powder with the vinyl silane coupling agent in step S1 is:

[0013] S101, add acetic acid to pure water to adjust the pH value to 3-4, then add ethanol and stir at 120-280 rpm for 3-6 minutes;

[0014] S102, add vinyl silane coupling agent and stir at 120-208 rpm for 3-6 minutes;

[0015] S103, then add insulating metal powder and stir at 160-308 rpm, while heating to 65-76°C and continuing stirring for 1.5-2h;

[0016] S14, after filtering out the aqueous solution, heat to 115-125° C., stir at a constant temperature and 220-620 rpm in vacuum for 0.6-1.2 h, and finally cool to room temperature to obtain the modified insulating metal powder.

[0017] Furthermore, the mass ratio of the insulating metal powder, the silane coupling agent, pure water and ethanol is 96-99:0.3-1.8:0.5-1.5:0.5-4.

[0018] The two-component thermally conductive insulating EMI shielding material is prepared by the preparation method described above.

[0019] The present invention has the following beneficial effects:

[0020] Excellent thermal conductivity: Two-component thermally conductive insulating EMI shielding materials can effectively conduct away the heat generated by electronic equipment, prevent equipment from overheating, and improve the safety and service life of the equipment.

[0021] Excellent electrical insulation performance: The two-component thermally conductive insulating EMI shielding material has excellent insulation, which can effectively isolate internal components and circuits, improve electrical stability, and ensure the normal operation of the equipment.

[0022] Good EMI shielding effect: It can achieve high shielding effectiveness in the range of 20M-20GHz, effectively reduce the impact of electromagnetic radiation on the equipment and the surrounding environment, and protect the equipment from external electromagnetic interference.

[0023] Wide applicability: Two-component thermally conductive insulating EMI shielding materials can be used in multiple fields such as consumer electronics, communication equipment, medical equipment, aerospace, military, unmanned driving and electric vehicles, meeting the needs of different industries for thermal conductivity, insulation and EMI shielding.

[0024] Flexible processing performance: Two-component thermally conductive insulating EMI shielding material has low viscosity, good fluidity, and is easy to process into various shapes and sizes to meet the potting and shielding needs of different equipment.

[0025] Of course, any product implementing the present invention does not necessarily need to achieve all of the advantages described above at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0027] Figure 1 The present invention is a flow chart of a method for preparing a two-component thermally conductive insulating EMI shielding material. DETAILED DESCRIPTION

[0028] 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.

[0029] In the description of the present invention, it should be understood that the terms "upper", "middle", "outer", "inner" and the like indicating directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the components or elements referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0031] See also Figure 1 As shown, the preparation method of the two-component thermally conductive insulating EMI shielding material of this embodiment includes the following steps:

[0032] S1, depositing an insulating layer on the surface of a metal powder by plasma vapor phase chemical deposition to obtain an insulating metal powder, and then modifying the insulating metal powder with a vinyl silane coupling agent to obtain a modified insulating metal powder;

[0033] S2. Under vacuum conditions, firstly, 3.8 parts of single-end vinyl-containing polysiloxane and 9.5 parts of 0.2 μm modified insulating metal powder were mixed by weight, stirred at 20 rpm, dispersed at 1000 rpm, and then stirred at a vacuum degree of -0.15 MPa for 10 min;

[0034] Then, 19 parts of 7 μm modified insulating metal powder were added to the obtained mixture, stirred at 20 rpm, dispersed at 800 rpm, and stirred for 10 min at a vacuum degree of -0.09 MPa;

[0035] 28.5 parts of 120 μm modified insulating metal powder were added to the obtained mixture, stirred at 20 rpm, dispersed at 300 rpm, and then stirred for 10 min at a vacuum degree of -0.2 MPa; the obtained mixture was heated and stirred to a temperature of 100°C, stirred at 20 rpm, and then stirred for 30 min at a vacuum degree of -0.2 MPa;

[0036] The obtained mixture was cooled to room temperature, 0.05 parts of platinum (0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex was added, and the mixture was stirred at 40 rpm, and then stirred for 10 minutes at a vacuum degree of -0.2 MPa to obtain the A component;

[0037] S3. Under vacuum conditions, 1.6 parts of single-end vinyl-containing polysiloxane and 9.5 parts of 3 μm modified insulating metal powder were mixed by weight, stirred at 20 rpm, dispersed at 1000 rpm, and then stirred at a vacuum degree of -0.15 MPa for 10 min;

[0038] 19 parts of 7 μm modified insulating metal powder were added to the obtained mixture, stirred at 20 rpm, dispersed at 800 rpm, and stirred for 10 min at a vacuum degree of -0.15 MPa;

[0039] 38.5 parts of 120 μm modified insulating metal powder were added to the obtained mixture, stirred at 20 rpm, dispersed at 300 rpm, and then stirred for 10 min at a vacuum degree of less than -0.15 MPa;

[0040] The mixture was heated and stirred to 100° C., stirred at 20 rpm, and then stirred for 30 min at a vacuum degree of less than -0.15 MPa;

[0041] The mixture was cooled to room temperature, 0.1 parts of side chain hydrogen-containing polysiloxane, 0.2 parts of single-end hydrogen-containing polysiloxane and 0.0005 parts of 1-ethynyl-1-cyclohexanol were added, and the mixture was stirred at a vacuum degree of -0.15 MPa for 10 minutes to obtain the B component;

[0042] S4. Component A and component B are mixed in a mass ratio of 1:1 and reacted to obtain a two-component thermally conductive insulating EMI shielding material.

[0043] In one embodiment, the method of modifying the insulating metal powder with the vinyl silane coupling agent in step S1 is:

[0044] S101, add acetic acid to 1 part of pure water to adjust the pH value to 3.5, then add 2 parts of ethanol and stir at 150 rpm for 4 minutes;

[0045] S102, add 1 part of vinyl silane coupling agent and stir at 200 rpm for 4 min;

[0046] S103, then add 98 parts of insulating metal powder and stir at 280 rpm while heating to 68°C

[0047] Then continue stirring for 1.6h;

[0048] S14, after filtering out the aqueous solution, heat to 120°C, stir at a constant temperature and 420 rpm for 1 hour in a vacuum, and finally cool to room temperature to obtain a modified insulating metal powder.

[0049] The two-component thermally conductive insulating EMI shielding material of this embodiment is prepared by the above-mentioned preparation method.

[0050] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0051] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing a two-component thermally conductive insulating EMI shielding material, characterized in that: The following steps are involved: S1. Depositing an insulating layer on the surface of a metal powder by plasma vapor phase chemical deposition to obtain an insulating metal powder, and then modifying the insulating metal powder with a vinyl silane coupling agent to obtain modified insulating metal powders with different particle sizes; S2. Under vacuum conditions, component A is prepared from 4-40 parts by weight of single-end vinyl-containing polysiloxane, 60-90 parts of modified insulating metal powders of different particle sizes, and 0.06-1 parts of a catalyst as raw materials; S3. Under vacuum conditions, component B is prepared from 2-30 parts by weight of single-end vinyl polysiloxane, 60-90 parts of modified insulating metal powders of different particle sizes, 0.5-5 parts of side chain hydrogen-containing polysiloxane, 1-10 parts of single-end hydrogen-containing polysiloxane and 0.0006-0.015 parts of inhibitor as raw materials; S4. Mix component A and component B in a mass ratio of 1:1 and react to obtain the two-component thermally conductive insulating EMI shielding material.

2. The method for preparing a two-component thermally conductive insulating EMI shielding material according to claim 1, characterized in that: The method for modifying the insulating metal powder by the vinyl silane coupling agent in step S1 is: S101, add acetic acid to pure water to adjust the pH value to 3-4, then add ethanol and stir at 120-280 rpm for 3-6 minutes; S102, add vinyl silane coupling agent and stir at 120-208 rpm for 3-6 minutes; S103, then add insulating metal powder and stir at 160-308 rpm, while heating to 65-76°C and continuing stirring for 1.5-2h; S14, after filtering out the aqueous solution, heat to 115-125° C., stir at a constant temperature and 220-620 rpm in vacuum for 0.6-1.2 h, and finally cool to room temperature to obtain the modified insulating metal powder.

3. The method for preparing a two-component thermally conductive insulating EMI shielding material according to claim 1, characterized in that: The mass ratio of the insulating metal powder, the silane coupling agent, pure water and ethanol is 96-99:0.3-1.8:0.5-1.5:0.5-4.

4. A two-component thermally conductive insulating EMI shielding material, characterized in that: A two-component thermally conductive insulating EMI shielding material is prepared by the preparation method described in any one of claims 1 to 3.

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