Double-layer pepper ball is also called compound pepper ball. Generally, the plastic ball inside is made of solid plastic pepper ball made of engineering plastic, and the outer layer is usually made of soft plastic with good elasticity. Its advantages are guaranteed strength and long service life, but its disadvantages are high manufacturing cost and low efficiency.It is relatively easy to manufacture the solid pepper ball inside the double-layer pepper ball, but the processing technology of the plastic ball outside is more complicated. Usually, PVC powder material is used. First, the PVC material is mixed into paste liquid, then the inner ball is heated. When the inner ball is heated to about 90 degrees, the inner ball is immersed in the PVC paste liquid, and then the plastic solid ball covered with PVC liquid is put into a special furnace for heating and molding. Generally, after more than 10 minutes of heating and molding, the molded composite pepper ball is taken out of the furnace.