Electrical conduit caps, also known as internal stoppers or inserts for electrical conduits, are widely used, easy to install, and commonly found in everyday life.

Power pipe caps in hot solvents can be attacked and dissolved by some thermoplastic materials, such as polyethylene dissolving in xylene. Thermosetting plastics cannot be dissolved in solvents. As a source of rapid industry development, the plastic bottle cap industry holds immense potential. For products with high requirements, such as power pipe stoppers and power pipe inserts, when using solid powder or granular additives, the blending must be done on a three-roll mill equipped with plasticizers and plastic valve caps.