Wet Modification And Application Of Kaolin

The green tire is the development direction of the tire, the use of green filler is one of the key ways for it. Our country is rich in kaolin, it has many good physical and chemical properties and process characteristics, meanwhile, it is cheap and easy to get, so the application of kaolin in tire attracts widespread attention. Because of the hydrophilic inorganic and lamellar structure, poor compatibility with rubber and bad dispersion in rubber, resulting in the limit of application in tire. In this paper, we used three arm remote claw type boric acid ester coupling agent and high speed dispersing machine to modify kaolin, and studied the application of modified kaolin in NR and SBR.In this paper, the preparation method of boric acid ester emulsion was studied.The results showed that, when the SDBS as an emulsifier, the particle size and distribution of the emulsion was smaller and narrower, the viscosity and Zeta potential was the biggest. The emulsion stability was better than others that PSS, CMC-Na and SA as emulsifier. When the emulsion concentration is 2%, the emulsifier is 2% of the Zr-201 dosage, the emulsion could be kept stable for a long time.The kaolin was wet modified with different time and different content of modifiers, then filled in the steel radial truck tire tread, meanwhile, the modification effect of kaolin was studied. When all of the silica was replaced by the modified kaolin, the processing performance was improved and the energy consumption was reduced. The resilience and tensile properties increased, the compression heat and hysteresis loss of vulcanizates reduced, the heat aging resistance became better, but the 300% modulus stress, abrasion resistance and tear resistance decreased. When the modification time was 10 min, the comprehensive performance of compound material was the best. The tensile strength and tear strength were first increased and then decreased with the Zr-201 content increased, but other properties showed no significant difference. When Zr-201 dosage of kaolin was 2%, the comprehensive performance of compound material was the best.In this paper, research focused on the optimum formula which is the application of wet modified kaolin in tread compound, and the efffects of Si-69, S, and anti-wear agent L-727 on tire tread was studied. The results showed that the processing performance improved with the Si-69 content decreased, the tensile strength, tear strength, and the dynamic compression performance of rubber were first increased and then decreased, the modulus stress and hardness decreased, the wear resistance and resilience changed a little, and the aging resistance properties decreased slightly. When Si-69 dosage was 2 phr, the comprehensive performance of compound material was the best. The rate of production improved with the S content increased, the value of(MH-ML)increased, the tensile strength and the aging resistance properties decreased slightly, the modulus stress, tear strength, hardness and resilience increased, the wear resistance and dynamic compression performance became better gradually. When S dosage was 1.3phr, the comprehensive performance of compound material was the best. The anti-wear agent L-727 was added to improve the tear strength and wear resistance obviously, when the modified kaolin and L-727 ratio reached 10:5, the comprehensive performance of vulcanizates was the best. Finally, the optimal ratio of anti-wear agent and modified kaolin, the amount of S and Si-69 was preferably used in the same compound, compared with the original recipe, the physical and mechanical properties improved significantly, especially the tear strength and wear resistance is increased by 15.1% and 18.9%, meanwhile, the gap between the silica formula reduced greatly.Compared with the conventional fillers such as carbon black and silica, the application of kaolin in the SBR compounds had lower mixing energy consumption and Payne, and better processing performance. The overall performance of vulcanizates had a large gap with N660 compounds, meanwhile, it was slightly inferior to silica, but obviously superior to calcium carbonate compound. Compared with the unmodified kaolin, the modified kaolin/SBR composites had higher mechanical properties and better wear resistance.