Study on high temperature resistant silicone / epoxy resin powder coating for automobile exhaust pipe


1 experimental part


1.1 experimental raw materials


Silicone resin, vn-203, silane coupling agent: Changzhou Jianuo silicone Co., Ltd.; silicon powder: industrial grade, Suzhou Jinyi inorganic New Material Technology Co., Ltd.; epoxy resin E-12: industrial grade, Huangshan Jinfeng Industrial Co., Ltd.; manganese iron black: Kunshan Qichuang Chemical Co., Ltd.; talcum powder: industrial grade, Changzhou fengshuo Chemical Co., Ltd.: leveling agent: Ningbo Nanhai Chemical Co., Ltd Ltd.: phenol curing agent: industrial grade, Lu'an jietongda Chemical Co., Ltd.


1.2 experimental equipment


Sp60: X-Rite, USA: thickness gauge (qnix4500): Nix, Germany; muffle furnace: Changzhou Xingguang kiln Co., Ltd.; solidified electric furnace: Nanjing boyuntong Instrument Technology Co., Ltd.; electrostatic powder coating spray gun: Swiss Jinma Co., Ltd.: electronic scale: METTLER TOLEDO instrument (Shanghai) Co., Ltd.; impact resistance instrument (qcj type): Kunshan Guojing Electronic Co., Ltd.: twin screw extruder (slj30a), pulverizer system (acm02): Yantai Donghui powder equipment Co., Ltd.; topsizer plus: Zhuhai OMAX Instrument Co., Ltd.


1.3 experiment process


1.3.1 formulation design of high temperature resistant powder coating


The application conditions of high temperature resistant powder coating are relatively bad, and the high temperature working time is long, so the requirements for coating performance are very high. First, the heat loss of raw materials is low under high temperature conditions. Second, the color retention of coating under high temperature is required to be high, otherwise it will affect the appearance, that is, the color retention of pigments and fillers under high temperature conditions is required to be high. Third, the mechanism of coating after use under high temperature conditions The mechanical properties of the coating are required to be high. If the coating is powdered, peeled or cracked after use at high temperature, the mechanical properties of the coating will be greatly reduced, which is also unable to meet the use requirements.


According to the literature, silicone silicone silicone resin has the best high temperature resistance, so in this experiment, silicone silicone resin was selected as the film-forming material of high temperature resistant powder coating, in order to reduce the cost, a small amount of epoxy resin was added. Table 1 shows the formula composition of typical high temperature resistant powder coating.


1.3.2 screening of pigments and fillers


Put the pigments and fillers of different manufacturers into muffle furnace with the same quality, bake at 600 ℃ for 1h, then take them out, observe the volatile matter and color change, and the color change is mainly subject to the color difference meter (60 °).


1.3.3 preparation process of powder coating


The pigments and fillers, organosilicon resin, epoxy resin, phenol curing agent and other raw materials selected above are added into the mixing cylinder according to the formula in Table 1, stirred for 4min at the speed of 400R / min, evenly stirred, poured into the twin-screw extruder, and extruded by melting. The heating bars of the extruder are 110 ℃ in zone I and 125 ℃ in zone II. After extrusion, they are cooled to room temperature and fed into the grinding powder When the particle size of powder coating is adjusted to 32-37 μ m, a large amount of powder can be ground to obtain high temperature resistant powder coating.


Wen / LV Ying 1, bu Qingpeng 2, Wang Xiaoqiang 2, pan Jianliang 2