Sealant- The Silicone Tube is a quick-setting sealant that sets in as little as 12 hours. The 100% silicone formula offers a translucent color that is UV resistant and permanently flexible. Compatible with polycarbonate sheet and most other kinds of plastics. A sealant is a viscous material that changes state to become a solid once it is applied. Sealants create a barrier to prevent the penetration of air, gas, dust, fire, smoke, liquid, and even noise from one location into another. Typically, sealants are used to close small openings that are difficult to eliminate through other processes or materials.