Development of Room Temperature Curing High Temperature Adhesive II

From Table 2, it can be seen that with the increase of the amount of the curing agent B, the shear strength at room temperature decreases, the shear strength at high temperature increases, and the peeling strength increases, indicating that the curing agent B has a great influence on the performance of the system; however, due to the curing agent The activity of B is relatively high. Adding too much of it will cause the system to burst. Comprehensive consideration of 50 selected better.

2.3 Effect of Accelerator on Adhesive Properties

According to 1.3.2 preparation of curing agent, the amount of accelerator added according to the epoxy resin mass 0%, 1%, 3%, 5% added to observe the room temperature curing 1d after the shear strength, peel strength and application period The changes are shown in Table 3.

From Table 3, it can be seen that the accelerator has a low reaction rate, the curing effect of the system is not good, and it is difficult to achieve high strength in a short period of time; the amount of the accelerator is too much, the curing speed of the system is increased, and the regularity of the molecular arrangement is decreased. The strength will also decrease, affecting the high temperature performance of the adhesive. Based on the above analysis, the choice of accelerator is about 3% better.

2.4 Effect of Mixed Fillers on High Temperature Resistance of Adhesives

In this experiment, asbestos and kaolin were used as mixed fillers, micron-sized asbestos and kaolin were dried at high temperature, organically activated with KH-550, then dried at high temperature for different periods of time, and finally vacuum dried. The unmodified and activated treated mixed fillers were added separately at 5% by weight of the epoxy resin. Room temperature curing 1d, measured shear strength and peel strength in Table 4.

From Table 4, it can be seen that mixed fillers have little effect on the shear strength strength and peel strength at normal temperature, but have a certain influence on the high temperature performance at 125°C and 250°C. The main reason is that the heat-resistant filler improves the anti-ablative properties of the adhesive. The active mixed fillers have better temperature resistance than untreated mixed fillers, mainly because of the condensation reaction of the alkoxy groups of the coupling agent on the surface of the filler, the increase of the crosslink density, the improvement of the heat resistance, and the high temperature shear of the adhesive. The intensity increased.

(to be continued)