Using epoxy resin as the sealing material of the hot runner electric heating tube, its formula and process are not exactly the same, there are basically two kinds.
One is the heating and pressurization process, which uses 634# epoxy resin and m-phenylenediamine, double-mixed according to the weight of 5:2 to form a mixed body potting, and seals with natural mica flakes at 20kg/cm2 It is formed by drying at 120°C for 4 hours under pressure.
The other is a non-pressurized heating process, which can use 6207 epoxy resin and maleic acid as the hardener. The sealing material formed can be used for a long time in a working environment of 250°C.
Special epoxy resin sealing materials can also be formulated according to the following ingredients:
Epoxy resin 634# 100 copies
35 parts of phthalic anhydride
Quartz powder (fumed silica) 270 mesh 150 parts
15 parts of dibutyl phthalate
Because this formula is mixed with silica, it has a significant effect on improving the thermal shock performance. It is not necessary to add silica in places where the thermal shock is not large.
Using epoxy resin as a sealing material, its temperature resistance is generally only about 150-250. The materials prepared during the sealing must be prepared and used. The performance of the electric heating tube components must be intact before sealing, otherwise, it will be difficult to rework after the epoxy resin is hardened.