High-conductivity silicone rubber with excellent processability and preparation method thereof

Abstract

The invention discloses high-conductivity silicone rubber with excellent processability and a preparation method thereof, and relates to the technical field of rubber materials, the high-conductivity silicone rubber comprises the following components by weight: 20-40 parts of raw rubber, 50-60 parts of a conductive filler, 5-15 parts of white carbon black, 1.5 parts of a structured control agent, 1.04 parts of a silane coupling agent, 0.05 part of a release agent, and 3 parts of a vulcanizing agent. The raw rubber is compounded by two or three different methyl vinyl silicone rubber, and the conductive filler is one or more of nickel-coated iron, nickel-coated graphite and furnace black. According to the high-conductivity silicone rubber with excellent processability and the preparation method thereof, the nickel-coated graphite and the furnace black are compounded for use, so that target resistance can be achieved with a smaller dosage, and the high-conductivity silicone rubber has the characteristics of small dosage of the conductive filler, low specific gravity and low cost.

Description

Technical Field

[0001] The invention relates to the technical field of rubber materials, in particular to a highly conductive silicone rubber with excellent processing performance and a preparation method thereof. Background Art

[0002] In the modern electronic and electrical fields, the demand for high-performance conductive materials continues to grow. With the miniaturization, integration and high performance of electronic equipment, reliable conductive connections and electromagnetic shielding materials are needed. Highly conductive silicone rubber can meet these needs and has broad application prospects in the packaging of electronic components, electromagnetic shielding, conductive connectors, etc. Silicone rubber has excellent heat resistance, cold resistance, weather resistance, electrical insulation and chemical stability.

[0003] However, the electrical conductivity of ordinary silicone rubber is poor, which limits its application in certain specific fields. To this end, we propose a highly conductive silicone rubber with excellent processing performance and a preparation method thereof. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a highly conductive silicone rubber with excellent processing performance and a preparation method thereof, which solves the problems raised in the above-mentioned background technology.

[0005] To achieve the above objectives, the present invention is implemented through the following technical scheme: a highly conductive silicone rubber with excellent processing performance, whose components are calculated by weight: 20 to 40 parts of raw rubber, 50 to 60 parts of conductive filler, 5 to 15 parts of white carbon black, 1.5 parts of structuring control agent, 1.04 parts of silane coupling agent, 0.05 parts of release agent, and 3 parts of vulcanizing agent.

[0006] Furthermore, the raw rubber is compounded by two or three different methyl vinyl silicone rubbers.

[0007] Furthermore, the conductive filler is one or more of nickel-coated iron, nickel-coated graphite, and furnace carbon black.

[0008] Furthermore, the white carbon black is fumed white carbon black, and the specific surface area is 180 to 200 m2 / g.

[0009] Furthermore, the structuring control agent is one or more of hydroxy silicone oil, hydrogen-containing silicone oil, vinyl hydroxy silicone oil, and dimethyl diethoxy silicone oil.

[0010] Furthermore, the silane coupling agent is one or more of A151, A172, and KH570.

[0011] Furthermore, the release agent is zinc stearate.

[0012] Furthermore, the vulcanizing agent is a platinum vulcanizing agent, and the A and B components are 1.5% each.

[0013] Furthermore, a method for preparing the highly conductive silicone rubber with excellent processing performance is characterized in that the steps are as follows:

[0014] S1: Adding raw rubber, white carbon black, structure control agent and release agent into a kneader several times and kneading into a shape;

[0015] S2: After S1 is kneaded and formed, the conductive filler and the silane coupling agent are added to the kneader in multiple times, kneaded and formed to obtain a silicone rubber compound;

[0016] S3: heating the material obtained in S2, evacuating the material and stirring the material;

[0017] S4: After the rubber is discharged, it is filtered and cooled to room temperature to obtain a highly conductive silicone rubber;

[0018] S5: The silicone rubber compound and platinum vulcanizer in S4 are added into an open rubber mixer and mixed evenly, and then placed in a flat vulcanizer for vulcanization to obtain a highly conductive silicone rubber.

[0019] Furthermore, during use, platinum vulcanizing agent is added, 1.5% of each component A and B, and the rubber material is evenly mixed in an open rubber mixer, and then molded and vulcanized on a flat vulcanizing press. The vulcanization temperature is 125°C, the vulcanization time is 10 minutes, and the vulcanization pressure is 15 MPa, so as to obtain the highly conductive silicone rubber.

[0020] The present invention provides a highly conductive silicone rubber with excellent processing performance and a preparation method thereof, which has the following beneficial effects:

[0021] 1. The highly conductive silicone rubber with excellent processing performance and the preparation method thereof can achieve the target resistance with less amount of conductive filler, low specific gravity and low cost by compounding nickel-coated graphite and furnace carbon black.

[0022] 2. The highly conductive silicone rubber with excellent processing performance and its preparation method, the prepared rubber conductive filler has a small filling amount and high plasticity. In addition to high conductivity, it has good processing performance. In addition to being used in compression molding process, it can also be used in extrusion molding process. At the same time, the preparation process is simple and convenient for large-scale production. DETAILED DESCRIPTION

[0023] The following examples are used to illustrate the present invention, but they are not intended to limit the scope of the present invention.

[0024] Embodiment 1

[0025] A highly conductive silicone rubber with excellent processing performance and a preparation method thereof, the preparation steps are as follows: first, 33 parts of raw rubber, 10 parts of white carbon black, 1.5 parts of a structuring control agent, and 0.05 parts of a release agent are kneaded in a kneader to form, and then 54.32 parts of a conductive filler and 1.04 parts of a silane coupling agent are added to the vacuum kneader for multiple times, and the mixture is stirred thoroughly after each addition, and the mixture is stirred and mixed evenly. After the rubber material is kneaded and formed, the temperature is raised to 150°C, hot-refined for 30 minutes, and then vacuumed to a vacuum degree of -0.07MPa, vacuumed for 30 minutes, cooled to 80°C by cooling water, and then cooled to room temperature to obtain the highly conductive silicone rubber.

[0026] Embodiment 2

[0027] A highly conductive silicone rubber with excellent processing performance and a preparation method thereof, the preparation steps are as follows: first, 32 parts of raw rubber, 9 parts of white carbon black, 1.23 parts of a structuring control agent, and 0.05 parts of a release agent are kneaded in a kneader to form, and then 56.7 parts of a conductive filler and 1.04 parts of a silane coupling agent are added to the vacuum kneader for multiple times, and the mixture is stirred thoroughly after each addition, and the mixture is stirred and mixed uniformly. After the rubber material is kneaded and formed, the temperature is raised to 150°C, hot-refined for 30 minutes, and then vacuumed to a vacuum degree of -0.07MPa, vacuumed for 30 minutes, cooled to 80°C by cooling water, and then cooled to room temperature to obtain the highly conductive silicone rubber.

[0028] Embodiment 3

[0029] A highly conductive silicone rubber with excellent processing performance and a preparation method thereof, the preparation steps are as follows: first, 30 parts of raw rubber, 9 parts of white carbon black, 1.17 parts of a structuring control agent, and 0.05 parts of a release agent are kneaded in a kneader to form, and then 58.74 parts of a conductive filler and 1.04 parts of a silane coupling agent are added to the vacuum kneader for multiple times, and the mixture is stirred thoroughly after each addition, and the mixture is stirred and mixed evenly. After the rubber material is kneaded and formed, the temperature is raised to 150°C, hot-refined for 30 minutes, and then vacuumed to a vacuum degree of -0.07MPa, vacuumed for 30 minutes, cooled to 80°C by cooling water, and then cooled to room temperature to obtain the highly conductive silicone rubber.

[0030] Platinum vulcanizer was added to the prepared high-conductivity silicone rubber, 1.5% of each component A and B, and mixed evenly in an open rubber mixer. Vulcanization was performed on a flat vulcanizer at a vulcanization temperature of 125°C, a vulcanization time of 10 minutes, and a vulcanization pressure of 15 MPa. The vulcanization was pressed into a 2 mm thick test piece for performance testing:

[0031] Hardness test: The test standard is GB / T 531.1-2008. Prepare a suitable hardness test instrument, such as a Shore hardness tester. Place a 2mm thick test piece made by vulcanization on the test platform of the hardness tester. Ensure that the surface of the test piece is flat and there are no obvious defects or impurities that affect the test results. Adjust the pointer of the hardness tester to zero, and then slowly and vertically press the indenter of the hardness tester on the surface of the test piece. The applied pressure should meet the requirements of the standard and be maintained for a certain period of time (usually a few seconds). After the pointer of the hardness tester stabilizes, read and record the hardness value.

[0032] Density test: The test standard is GB / T533-1991. According to GB / T 533-1991, first measure the size of the test piece, accurate to 0.01mm, calculate the volume V of the test piece, use a precision balance to weigh the mass m of the test piece, the accuracy of the balance should meet the standard requirements, and calculate the density of the high conductive silicone rubber test piece according to the density calculation formula ρ=m / V, and record the data.

[0033] Tensile strength and elongation at break test: The test standard is GB / T 528-2009. According to GB / T 528-2009 standard, prepare an electronic universal material testing machine and adjust the test parameters, such as stretching speed, etc. Cut the 2mm thick test piece into a standard dumbbell-shaped specimen. The size of the specimen should strictly comply with the standard requirements to ensure that there is no damage or defect in the preparation of the specimen. Install the dumbbell-shaped specimen on the upper and lower clamps of the material testing machine to ensure that the specimen is evenly stressed during the stretching process and that the axis is consistent with the direction of the tension. Start the testing machine and stretch the specimen at the specified stretching speed. At the same time, record the force-displacement data during the stretching process until the specimen breaks. Calculate the tensile strength (maximum tensile force at break divided by the original cross-sectional area of ​​the specimen) and elongation at break (elongation at break divided by the original gauge length of the specimen multiplied by 100%) based on the test data, and record the test results.

[0034] Surface resistance test: The test standard is GB / T20891-2019. According to GB / T 20891-2019 standard, prepare a surface resistance tester, place the vulcanized 2mm thick test piece on the test bench, ensure that the test piece is in good contact with the test electrode, and the contact area and pressure should meet the standard requirements. Turn on the surface resistance tester, read the surface resistance value of the test piece after the instrument stabilizes and record it. During the test, avoid the influence of external interference factors on the test results, such as static electricity, electromagnetic interference, etc.

[0035] The performance test data of the 2 mm thick test piece made of the thermal conductive silicone rubber of the present invention is as follows:

[0036] Test items Embodiment 1 Embodiment 2 Embodiment 3 Hardness(Shore A) 75 76 78 Surface resistance(Ω) 3.6 2.9 1.8 <![CDATA[Density (kg / m 3 )]]> 1.83 1.87 1.93 Tensile strength(MPa) 2.75 2.21 2.02 Elongation(%) 203 152 128

[0037] From the table, it can be concluded that the present invention provides a highly conductive silicone rubber with excellent processing performance, hardness (Shore)>75A, tensile strength>2MPa, elongation at break>100%, and minimum surface resistance<2Ω. The process is simple and the cost can be effectively reduced.

[0038] The embodiments of the present invention are given for the purpose of illustration and description, and are not intended to be exhaustive or to limit the invention to the disclosed forms. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. A highly conductive silicone rubber with excellent processing performance, characterized in that: The components thereof are as follows by weight: 20-40 parts of raw rubber, 50-60 parts of conductive filler, 5-15 parts of white carbon black, 1.5 parts of structural control agent, 1.04 parts of silane coupling agent, 0.05 parts of release agent and 3 parts of vulcanizing agent.

2. The highly conductive silicone rubber with excellent processing performance according to claim 1, characterized in that: The raw rubber is compounded by two or three different methyl vinyl silicone rubbers.

3. The highly conductive silicone rubber with excellent processing performance according to claim 1, characterized in that: The conductive filler is one or more of nickel-coated iron, nickel-coated graphite, and furnace carbon black.

4. The highly conductive silicone rubber with excellent processing performance according to claim 1, characterized in that: White carbon black is fumed white carbon black with a specific surface area of ​​180 to 200 m2 / g.

5. The highly conductive silicone rubber with excellent processing performance according to claim 1, characterized in that: The structuring control agent is one or more of hydroxy silicone oil, hydrogen silicone oil, vinyl hydroxy silicone oil, and dimethyl diethoxy silicone oil.

6. The highly conductive silicone rubber with excellent processing performance according to claim 1, characterized in that: The silane coupling agent is one or more of A151, A172, and KH570.

7. The highly conductive silicone rubber with excellent processing performance according to claim 6, characterized in that: The release agent is zinc stearate.

8. The highly conductive silicone rubber with excellent processing performance according to claim 6, characterized in that: The vulcanizing agent is platinum vulcanizing agent, and the A and B components are 1.5% each.

9. A method for preparing a highly conductive silicone rubber with excellent processing performance as claimed in claim 8, characterized in that: The steps are: S1: Adding raw rubber, white carbon black, structure control agent and release agent into a kneader several times and kneading into a molding; S2: After S1 is kneaded and formed, the conductive filler and the silane coupling agent are added into the kneader in multiple times, kneaded and formed to obtain a silicone rubber compound; S3: heating the material obtained in S2, evacuating the material and stirring the material; S4: After the rubber is discharged, it is filtered and cooled to room temperature to obtain a highly conductive silicone rubber; S5: The silicone rubber compound and platinum vulcanizer in S4 are added into an open rubber mixer and mixed evenly, and then placed in a flat vulcanizer for vulcanization to obtain a highly conductive silicone rubber.

10. The method for preparing a highly conductive silicone rubber with excellent processing performance according to claim 9, characterized in that: The platinum vulcanizer added during use, 1.5% of each component A and B, is mixed evenly in an open rubber mixer and then subjected to compression vulcanization on a flat vulcanizer. The vulcanization temperature is 125°C, the vulcanization time is 10 minutes, and the vulcanization pressure is 15 MPa, thereby obtaining the highly conductive silicone rubber.