Friction coefficient of functional design of flexible packaging
The coefficient of friction has an important influence on the opening of the packaging bag, the adaptability of the roll stock to automatic packaging, and the operability of the bag-making process in the packaging factory.
When there is relative motion or relative motion tendency between two objects in contact with each other, the mechanical force on the contact surface that hinders the relative motion is the frictional force. The friction performance of a material can be characterized by the coefficient of dynamic and static friction of the material. Static friction is the maximum resistance of two contact surfaces at the beginning of relative movement, and its ratio to the normal force is the coefficient of static friction. Kinetic friction is the resistance of the two contact surfaces when they move relative to each other at a certain speed, and the ratio to the normal force is the kinetic friction coefficient.
When studying the friction coefficient, special attention should be paid to the great influence of temperature on the friction coefficient. Therefore, not only the friction coefficient of the packaging material at room temperature should be measured, but also the friction coefficient at the actual use environment temperature should be investigated. The temperature conditions of the film may be different in actual use, such as in tropical climate conditions, high temperature conditions of heat sealing rods of cigarette packaging machines, etc. Usually from 30°C onwards, the coefficient of friction of the film rises sharply. This is because the commonly used lubricants are close to their melting point and become bonded. The force applied during the test fluctuates greatly, showing an intermittent sliding bonding effect. In order to alleviate this intermittent slip-stick phenomenon, another completely different high temperature lubricant is required - silicone, which has unique properties due to its high molecular weight polymer, even at higher temperature friction coefficient remains low.
