喷涂型汽车油箱点焊密封胶的研制

Study on preparing sprayable spot-welding sealant for automobile fuel tank

从油箱喷塑固化工艺条件出发,以环氧树脂(EP)和小分子聚酰胺为主要原料,制备了两种不同配方的汽车油箱用点焊密封胶。测试了点焊胶在90#汽油和0#柴油中的耐油性和粘接强度,并对三种不同连接接头(胶接、点焊、胶焊)的粘接强度进行了对比和分析。结果表明:点焊胶的固化工艺与汽车镀锌板类油箱表面漆层的固化工艺相同,故不必增加点焊胶的固化设备和工序;两种点焊胶具有较好的粘接性能,其T型剥离强度分别为89.0kN/m和92.0kN/m,拉伸剪切强度分别为13.3MPa和12.9MPa;两种点焊胶在90#汽油和0#柴油中浸泡360d后,试样的粘接强度降幅不明显,说明其具有一定程度的耐油性;将两种点焊胶用于汽车油箱的密封中,既具有良好的粘接密封性能,又解决了镀锌板类油箱渗漏油等问题。

With epoxy resin（EP） and polyamide with small molecule as main materials, so two types of sprayable spot-welding sealants with different formula for automobile fuel tank were prepared based on curing process conditions of fuel tank surface coat spurted by plastic. The oil-resistance and bonding strength in 90# gasoline or 0~ diesel oil were tested for spot-welding sealants, and the bonding strength of three different joints（such as bonding, spot-welding and bond-welding） were respectively compared and analysed. The results showed that the spot-welding sealants need not add curing equipment and process because the curing process conditions between spot-welding sealant and automobile fuel tank surface（namely galvanized plate＇s surface） coat spurted by plastic were same. Two types of spot-welding sealants had better bonding performances and oil-resistance because their T-peeling strengths were 89.0 kN/m and 92.0 kN/m respectively, and tensile shear strengths were 13.3 MPa and 12.9 MPa respectively, the decrease of bonding strength weren＇t obvious after marinating in 90# gasoline or 0# diesel oil for 360 d. Two types of spot-welding sealants, which were used as sealants of automobile fuel tank, had well bonding airproofing performance, and could solve the problem of leaking oil from galvanized plate＇s gap of fuel tank.