Plastic bottles have found increasingly wide application in the food and beverage industries nowadays, with plastic bottles in all shapes and sizes for soft drinks, juices and water found everywhere in our daily life. Along with their wider application and acceptance are more, and stricter, requirements for quality and safety control and testing. One such test is the pull-off strength of plastic bottle caps where the force required to pull the bottle cap off the bottle is routinely checked and monitored by manufacturers. These manufacturers commonly use a Tinius Olsen tensile tester to take these measurements. In these cases, Tinius Olsen recommends the use of the grip attachment model S540, which comprises of two parts; the lower bottle cap holder and the upper cap “Pull off” attachment. Operators simply insert the cap in the lower attachment, lower the upper attachment onto the cap and start the tensile test; at the end of the test, the testing machine reports the “Pull Off force”
Users typically test one in 3000 bottle caps and monitor the standard deviation of results to ensure a consistent pull off force.