Plastic cover classification
One: without air cap
Air-free caps are also called airtight caps, plastic caps, anti-theft caps, etc.
It has good airtightness, and there is a ring-shaped leak-proof ring on the inner wall of the top of the general plastic cover; there are also ordinary plastic bucket covers that need to be matched with the inner cover, so there is no need to design a leak-proof ring; there are several ribs around the main body of the plastic cover, Facilitate the application of torsion force on the plastic cover
Two: air cover
Air-containing caps are also called vent caps, exhaust caps, combined vent caps, and so on.
The breathable cover is generally composed of a main body outer cover with small holes and an inner cover with a breathable membrane. The breathable membrane can effectively vent and block the effect of liquid. This cover can balance the pressure inside and outside the container to avoid The product expands or contracts due to physical or chemical changes
Three: inner cover
The inner cap also becomes the inner stopper, the inner cap of the barrel mouth, the inner cap of the bottle mouth, the stopper, etc.
Generally, containers with a capacity of more than 3L can be equipped with an inner lid. The inner lid increases the tightness of the container, and the sealing effect is better than a single outer lid!