Silicone rubber with double functions of heat conduction and electromagnetic shielding and preparation method thereof

Abstract

The invention discloses silicon rubber with double functions of heat conduction and electromagnetic shielding and a preparation method thereof, and belongs to the technical field of rubber materials. According to the invention, the magnetic conductive filler aluminum nickel-plated powder or aluminum iron-plated powder, and the heat-conducting filler alpha-Al2O3, aluminum nitride or carbon nanotubes are added into the silicone rubber, so that the prepared silicone rubber has good heat-conducting property and electromagnetic shielding property at the same time. The heat conduction coefficient can reach 2.0 W / (m.K) or above, the electromagnetic shielding effectiveness is 60 dB or above, the tensile strength at break is larger than or equal to 3 MPa, the elongation at break is larger than or equal to 100%, the excellent electromagnetic shielding effectiveness, heat conduction performance and mechanical performance are achieved, and the requirements of electronic equipment for heat dissipation and electromagnetic protection can be met.

Description

Technical Field

[0001] The invention belongs to the technical field of rubber materials, and in particular relates to a heat-conducting and electromagnetic-shielding dual-function silicone rubber and a preparation method thereof. Background Art

[0002] With the increasing popularity of electronic devices and the continuous improvement of their performance, the heat and electromagnetic radiation generated by electronic devices during operation have a serious impact on the performance and reliability of the equipment. Silicone rubber, as a polymer material with excellent flexibility, high and low temperature resistance and electrical insulation, has been widely used in the field of electronic packaging. However, the thermal conductivity and electromagnetic shielding properties of traditional silicone rubber are poor, and cannot meet the heat dissipation and electromagnetic protection requirements of modern electronic equipment. Therefore, it is of great practical significance to develop a silicone rubber with both good thermal conductivity and electromagnetic shielding properties. Summary of the invention

[0003] The present invention aims to provide a heat-conducting and electromagnetic shielding dual-function silicone rubber and a preparation method thereof. The method comprises adding magnetic filler aluminum-nickel-plated powder or aluminum-iron-plated powder, heat-conducting filler α-Al 2 O 3 , aluminum nitride or carbon nanotubes to prepare silicone rubber with good thermal conductivity and electromagnetic shielding properties.

[0004] The specific steps of the present invention are as follows: A heat-conducting and electromagnetic shielding dual-function silicone rubber is prepared from the following raw materials in parts by weight: 100 parts of base material, 200-260 parts of magnetic conductive filler, 10-80 parts of thermal conductive filler, 2-4 parts of vulcanizer, and 2 parts of softener; the base material is dimethyl silicone rubber, methyl vinyl silicone rubber or methyl phenyl vinyl silicone rubber, the magnetic conductive filler is aluminum nickel-plated powder or aluminum iron-plated powder, and the thermal conductive filler is α-Al 2 O 3 , aluminum nitride or carbon nanotubes, the vulcanizing agent is 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (DBPMH), 2,4-dichlorobenzoyl peroxide (DCBP), diisopropylbenzene peroxide (DCP) or a platinum catalyst, and the softening agent is paraffin or vaseline.

[0005] A method for preparing a heat-conducting and electromagnetic-shielding dual-function silicone rubber is carried out according to the following steps: Step 1, prepare raw materials: prepare base material, magnetic conductive filler, thermal conductive filler, vulcanizer and softener; Step 2, filler pretreatment: the thermal conductive filler and the magnetic conductive filler are mixed evenly in a high-speed mixer, and then a silane coupling agent is added, and the mixture is continued to be mixed to obtain a pretreated filler; Step 3, mixing: adding the base material, vulcanizing agent and softening agent prepared in step 1 and the pretreated filler obtained in step 2 into an open mill and mixing them thoroughly; Step 4, vulcanization: Put the materials mixed evenly in step 3 into a vulcanizer for vulcanization, so that the silicone rubber and the filler are closely combined to form a silicone rubber with dual functions of heat conduction and electromagnetic shielding; Step 5, processing: the vulcanized thermal conductive and electromagnetic shielding dual-function silicone rubber is processed into a desired shape by molding or cutting.

[0006] In the above technical solution, in step 1, the raw materials are respectively as follows in parts by weight: 100 parts of base material, 200-260 parts of magnetic conductive filler, 10-80 parts of thermal conductive filler, 2-4 parts of vulcanizing agent, and 2 parts of softener.

[0007] In the above technical solution, in step 1, the silicone rubber is dimethyl silicone rubber, methyl vinyl silicone rubber or methyl phenyl vinyl silicone rubber, the magnetic conductive filler is aluminum nickel-plated powder or aluminum iron-plated powder, the vulcanizing agent is 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (DBPMH), 2,4-dichlorobenzoyl peroxide (DCBP), diisopropylbenzene peroxide (DCP) or a platinum catalyst, and the softener is paraffin or vaseline.

[0008] In the above technical solution, in step 2, the silane coupling agent is mercaptopropyltrimethoxysilane coupling agent (A189), vinyltriethoxysilane (A151) or octyltriethoxysilane coupling agent (A137).

[0009] In the above technical solution, in step 3, the mixing temperature is 30° C., and the mixing time is 60 min-90 min.

[0010] In the above technical solution, in step 4, the vulcanization temperature is 180° C.-210° C., and the vulcanization time is 300 minutes.

[0011] Beneficial effects: 1. The present invention reasonably selects thermal conductive fillers and electromagnetic shielding fillers and adopts a specific preparation method to make the prepared silicone rubber have good thermal conductivity and electromagnetic shielding performance. The thermal conductivity coefficient can reach more than 2.0 W / (m·K), which is conducive to the rapid dissipation of heat inside the equipment; the electromagnetic shielding effectiveness is more than 60 dB, which can meet the requirements of electronic equipment for heat dissipation and electromagnetic protection.

[0012] 2. Excellent mechanical properties: The silicone rubber matrix itself has good mechanical properties, with tensile strength at break ≥3MPa and elongation at break ≥100%. DETAILED DESCRIPTION

[0013] The present invention is described in detail below in conjunction with embodiments, but the present invention is not limited to these embodiments.

[0014] The filler aluminum nickel-plated powder and aluminum iron-plated powder in the embodiments of the present invention are raw materials prepared in the laboratory, and other raw materials are purchased through commercial channels.

[0015] The analysis method in the embodiment of the present invention is as follows: The present invention is further described in detail below in conjunction with specific embodiments.

[0016] Example 1 A heat-conducting and electromagnetic-shielding dual-function silicone rubber comprises the following raw materials in parts by weight: 100 parts of methyl vinyl silicone rubber; α-Al 2 O 3 50 copies; 200 parts of aluminum nickel plating powder; Silane coupling agent A189 5 parts; Curing agent DBPMH 2 parts.

[0017] Specifically, the preparation method of the dual-function silicone rubber with thermal conductivity and electromagnetic shielding comprises the following steps: 1) Filler pretreatment α-Al 2 O 3 The aluminum-nickel-plated powder and the aluminum-nickel-plated powder were mixed evenly in a high-speed mixer, and then the silane coupling agent A189 was added and the mixing was continued for 1.5 hours to obtain a pretreated filler.

[0018] 2) Mixing After accurately weighing each component according to the above weight portion, place it in an open mixer for mixing; during mixing, control the mixing temperature to be 30° C. and the mixing time to be 60 min.

[0019] 3) Compression molding The above-mentioned mixed rubber was molded using a flat-plate vulcanizer, and then subjected to two-stage vulcanization; wherein the molding temperature was controlled to be 180°C, the molding pressure was controlled to be 20 MPa, and the molding time was controlled to be 5 min; the temperature of the two-stage vulcanization was controlled to be 180°C, and the time was controlled to be 300 min, thereby obtaining a dual-function silicone rubber with thermal conductivity and electromagnetic shielding.

[0020] Example 2 A heat-conducting and electromagnetic-shielding dual-function silicone rubber comprises the following raw materials in parts by weight: 100 parts of methyl vinyl silicone rubber; α-Al 2 O 3 80 copies; 220 parts of aluminum nickel plating powder; Silane coupling agent A151 5 parts; Curing agent DBPMH 2 parts.

[0021] Specifically, the preparation method of the dual-function silicone rubber with thermal conductivity and electromagnetic shielding comprises the following steps: 1) Filler pretreatment Aluminum nitride and aluminum nickel-plated powder were mixed evenly in a high-speed mixer, and then silane coupling agent A151 was added and mixed for 1.5 hours to obtain a pretreated filler.

[0022] 2) Mixing After accurately weighing each component according to the above weight portion, place it in an open mixer for mixing; during mixing, control the mixing temperature to be 30° C. and the mixing time to be 60 min.

[0023] 3) Compression molding The above-mentioned mixed rubber is molded using a flat-plate vulcanizer, and then subjected to two-stage vulcanization; wherein the molding temperature is controlled to be 180°C, the molding pressure is controlled to be 20 MPa, and the molding time is controlled to be 10 min; the temperature of the second-stage vulcanization is controlled to be 180°C, and the time is controlled to be 300 min, to obtain a dual-function silicone rubber with thermal conductivity and electromagnetic shielding.

[0024] Example 3 A heat-conducting and electromagnetic-shielding dual-function silicone rubber comprises the following raw materials in parts by weight: 100 parts of methyl vinyl silicone rubber; 80 parts of aluminum nitride; 240 parts of aluminum nickel plating powder; Silane coupling agent A151 5 parts; 2 parts of softener paraffin; Curing agent DBPMH 4 parts.

[0025] Specifically, the preparation method of the dual-function silicone rubber with thermal conductivity and electromagnetic shielding comprises the following steps: 1) Filler pretreatment The carbon nanotubes and aluminum nickel-plated powder were mixed evenly in a high-speed mixer, and then the silane coupling agent A151 was added and the mixing was continued for 2 hours to obtain a pretreated filler.

[0026] 2) Mixing After accurately weighing each component according to the above weight portion, place it in an open mixer for mixing; during mixing, control the mixing temperature to be 30° C. and the mixing time to be 90 min.

[0027] 3) Molding The mixed rubber was extruded and formed by an extruder, and then subjected to two-stage vulcanization; wherein the temperature of the tunnel furnace was 180°C, the belt conveying speed was 10 m / min, the temperature of the second-stage vulcanization was 210°C, and the time was 300 min, thereby obtaining a thermally conductive and electromagnetically shielding dual-functional silicone rubber.

[0028] Example 4 A heat-conducting and electromagnetic-shielding dual-function silicone rubber comprises the following raw materials in parts by weight: 100 parts of methyl vinyl silicone rubber; 10 parts of carbon nanotubes; 260 parts of aluminum nickel plating powder; Silane coupling agent A137 20 parts; 2 parts of softener paraffin; Platinum catalyst 0.2 parts; 10 parts of hydrogen silicone oil.

[0029] Specifically, the preparation method of the dual-function silicone rubber with thermal conductivity and electromagnetic shielding comprises the following steps: 1) Filler pretreatment The carbon nanotubes and aluminum nickel-plated powder were mixed evenly in a high-speed mixer, and then the silane coupling agent A137 was added and the mixture was mixed for 2 hours to obtain a pretreated filler.

[0030] 2) Mixing After accurately weighing each component according to the above weight portion, place it in an open mixer for mixing; during mixing, control the mixing temperature to be 30° C. and the mixing time to be 90 min.

[0031] 3) Extrusion molding The mixed rubber is extruded and molded by an extruder, and then subjected to two-stage vulcanization; wherein the temperature of the tunnel furnace is 160°C, the belt conveying speed is 8 m / min, the temperature of the two-stage vulcanization is 210°C, and the time is 300 min, to obtain a conductive rubber.

[0032] Example 5 A heat-conducting and electromagnetic-shielding dual-function silicone rubber comprises the following raw materials in parts by weight: 100 parts of methyl vinyl silicone rubber; 20 parts of carbon nanotubes; 260 parts of aluminum iron plating powder; Silane coupling agent A137 20 parts; 2 parts of softener Vaseline; 0.2 parts of platinum catalyst; 10 parts of hydrogen silicone oil.

[0033] Specifically, the preparation method of the dual-function silicone rubber with thermal conductivity and electromagnetic shielding comprises the following steps: 1) Filler pretreatment α-Al 2 O 3 and aluminum-plated iron powder were mixed evenly in a high-speed mixer, and then silane coupling agent A137 was added and mixed for 2 hours to obtain a pretreated filler; 2) Mixing After accurately weighing each component according to the above weight portion, place it in an open mixer for mixing; during mixing, control the mixing temperature to be 30° C. and the mixing time to be 90 min.

[0034] 3) Extrusion molding The mixed rubber is extruded and molded by an extruder, and then subjected to two-stage vulcanization; wherein the temperature of the tunnel furnace is 160°C, the belt conveying speed is 8m / min, the temperature of the two-stage vulcanization is 210°C, and the time is 300 min, to obtain a conductive rubber.

[0035] Comparative Example 1 Compared with Example 1, no thermal conductive filler is added, and the remaining raw materials and preparation methods are the same.

[0036] Comparative Example 2 Compared with Example 1, no magnetic conductive filler is added, and the remaining raw materials and preparation methods are the same.

[0037] Comparative Example 3 Compared with Example 1, no magnetic conductive filler or thermal conductive filler is added, and the remaining raw materials and preparation methods are the same.

[0038] The performance of the prepared thermal conductive and electromagnetic shielding dual-functional silicone rubber was tested.

[0039] Mechanical properties: According to GB / T 528-2009 Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber, the tensile strength at break and the elongation at break are tested.

[0040] Electromagnetic shielding performance: According to GB / T 30142-2013 Measurement method for shielding effectiveness of planar electromagnetic shielding materials, the electromagnetic shielding performance is tested in the frequency range of 30 MHz~3 GHz.

[0041] Thermal conductivity: Thermal conductivity is tested according to GB / T 11205-2009 hot wire method for determination of thermal conductivity of rubber.

[0042] The thermal conductivity, electromagnetic shielding effectiveness, tensile strength at break and elongation at break of the silicone rubber prepared in Examples 1-5 and Comparative Examples 1-3 were tested and the results are shown in the following table: Table 1 Test results comparison table

[0043] It can be seen from the above test results that the thermal conductive and electromagnetic shielding dual-function silicone rubber prepared in the present invention has excellent thermal conductive properties, electromagnetic shielding properties and mechanical properties.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A thermally conductive and electromagnetically shielding dual-function silicone rubber, characterized in that: The invention is prepared from the following raw materials in parts by weight: 100 parts of base material, 200-260 parts of magnetic conductive filler, 10-80 parts of thermal conductive filler, 2-4 parts of vulcanizing agent and 2 parts of softening agent; the base material is dimethyl silicone rubber, methyl vinyl silicone rubber or methyl phenyl vinyl silicone rubber, the magnetic conductive filler is aluminum nickel-plated powder or aluminum iron-plated powder, the thermal conductive filler is α-Al2O3, aluminum nitride or carbon nanotubes, the vulcanizing agent is 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 2,4-dichlorobenzoyl peroxide, diisopropylbenzene peroxide or platinum catalyst, and the softening agent is paraffin or vaseline.

2. A method for preparing a dual-function silicone rubber having thermal conductivity and electromagnetic shielding, characterized in that: Follow the steps below: Step 1, prepare raw materials: prepare base material, magnetic conductive filler, thermal conductive filler, vulcanizer and softener; Step 2, filler pretreatment: the thermal conductive filler and the magnetic conductive filler are mixed evenly in a high-speed mixer, and then a silane coupling agent is added, and the mixture is continued to be mixed to obtain a pretreated filler; Step 3, mixing: adding the base material, vulcanizing agent and softening agent prepared in step 1 and the pretreated filler obtained in step 2 into an open mill and mixing them thoroughly; Step 4, vulcanization: Put the materials mixed evenly in step 3 into a vulcanizer for vulcanization, so that the silicone rubber and the filler are closely combined to form a silicone rubber with dual functions of heat conduction and electromagnetic shielding; Step 5, processing: the vulcanized thermal conductive and electromagnetic shielding dual-function silicone rubber is processed into a desired shape by molding or cutting.

3. The method for preparing a heat-conducting and electromagnetic-shielding dual-function silicone rubber according to claim 2, characterized in that: In step 1, the raw materials are respectively as follows in parts by weight: 100 parts of base material, 200-260 parts of magnetic conductive filler, 10-80 parts of thermal conductive filler, 2-4 parts of vulcanizing agent, and 2 parts of softening agent.

4. The method for preparing a heat-conducting and electromagnetic-shielding dual-function silicone rubber according to claim 2, characterized in that: In step 1, the silicone rubber is dimethyl silicone rubber, methyl vinyl silicone rubber or methyl phenyl vinyl silicone rubber, the magnetic conductive filler is aluminum nickel-plated powder or aluminum iron-plated powder, the vulcanizing agent is 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, 2,4-dichlorobenzoyl peroxide, diisopropylbenzene peroxide or platinum catalyst, and the softener is paraffin or vaseline.

5. The method for preparing a heat-conducting and electromagnetic-shielding dual-functional silicone rubber according to claim 2, characterized in that: In step 2, the silane coupling agent is mercaptopropyltrimethoxysilane coupling agent, vinyltriethoxysilane or octyltriethoxysilane coupling agent.

6. The method for preparing a heat-conducting and electromagnetic-shielding dual-functional silicone rubber according to claim 2, characterized in that: In step 3, the mixing temperature is 30° C., and the mixing time is 60 min-90 min.

7. The method for preparing a heat-conducting and electromagnetic-shielding dual-functional silicone rubber according to claim 2, characterized in that: In step 4, the vulcanization temperature is 180° C.-210° C., and the vulcanization time is 300 min.

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