Effect of Carbon Black Variety on the Wear Resistance of Silicone Rubber Mixed with Conductive Silicone Rubber Self-adhesive Tape
100 parts of methyl vinyl silicone rubber with 0.5% mole fraction of (CH3)(CHr=CH)SiO link ends at both ends of the molecule (CH3)3Si01/2 chain links (polymerization degree about 6,000) Add 20 parts of furnace carbon black a (product of Mitsubishi Chemicals Co., Ltd.: RCF# 10) with a particle size of 84nm and a DBP oil absorption of 0.86 mL/g, and a hydrochloric acid absorption volume of 0.20 mL/g, and an iodine adsorption value. 30 parts of 48 mg/g acetylene carbon black (products of Nihon Denki Industry Co., Ltd.: Yin>Li 7E, /Xi HS-100) are mixed in a kneader to form a rubber compound. The rubber material is mixed uniformly with 2 parts of the vulcanizing agent 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane on a double-roll rubber mixing machine to form a conductive mixed silicone rubber. For comparison, replace the furnace carbon black a in the above formula with 20 parts of furnace carbon black b (Mitsubishi Chemicals product: RCF#40) with a primary particle size of 24 nm and a DBP oil absorption of 1.1 mL/g. Mixed silicone rubber; without furnace carbon black, 50 parts of acetylene carbon black are used alone to make conductive mixed silicone rubber. Then, the prepared 3 kinds of mixed silicone rubbers were hot-pressed and vulcanized at 170 °C for 10 min to form, and then vulcanized at 200 °C for 4 h to make test pieces. The Akron abrasion and Taber abrasion were measured. Measure volume resistivity.
Effect of Carbon Black Variety on Wear Resistance of Conductive Mixed Silicone Rubber
Note: ①speed 250r/min, sample contact angle 10°, test revolutions 1000 times; ②speed 60r/min, load 500g, wear wheel 11-18, test revolutions 2,000 times.
In order to prepare highly conductive compounded silicone rubber, when a large amount of conductive carbon black is filled into the raw silicone rubber, the viscosity of the compound is usually too high, the processability is significantly reduced, and the vulcanizing agent loses its effect due to the strong surface activity of the carbon black. , It is difficult to obtain stable sulfide. The furnace carbon black with ADBP oil absorption of 0.40~1.5 mL/g and Dmod particle size (particle size in aggregate state) of 250~400 rnn can be used to produce carbon black with high filling content, good processability and stable sulfide properties. High conductivity compounded silicone rubber [227]. The ADBP oil absorption value of carbon black is the difference between the DBP oil absorption and the compressed DBP oil absorption (24M4DBP oil absorption, ASTM.D3493), which is a characterizing parameter of the degree of carbon black agglomeration. It is difficult to obtain the desired conductivity with ADBP less than 0.40 mL/g. The compound formulated with ADBP at 1.5 mL/g has high viscosity and poor processability. When the Dmod particle size of carbon black is less than 250 run, the dispersibility in the raw silicone rubber is not good, which makes the viscosity of the rubber too large and the processability becomes worse; while when it is greater than 400 nm, the conductivity is not ideal. Suitable carbon black specifications for high-conductivity mixed silicone rubber: ①DBP oil absorption 1.0~1.5 mL/g; ②Specific surface area (ASTMD 3037) 30 m2/g or less; ③UV absorbance below 0.1;④ The true density is above 1.82.
