Rheological tests on cap liners manufactured for plastic bottle caps

Did you know that the liner inside a bottle cap is a highly engineered part? Selecting a suitable cap liner is a critical task in order to ensure a tight seal upon closing the bottle cap. When the bottles contain food items, water, soft drinks, medicines and products that are directly associated with consumer safety, the material of the seal is of utmost importance. The liner materials are chosen based on various requirements like leakage prevention, creating a moisture barrier, chemical resistance, and shelf life. A wide variety of polymers (Teflon, silicone, polyolefins), paper-backed foams, aluminum foils, are used for manufacturing cap liners.