Friction Reducer
Fatty acid derivatives serve as functional additives to lower the coefficient of friction on the surface of polyolefin films. While erucamide is typically used in low density polyethylene and polypropylene, its primary role is to ensure that plastic sheets do not stick to themselves or to metal processing equipment. Surface lubrication ensures that materials move efficiently through high speed bag making and automated filling operations.
Migration Mechanism
Melt blending incorporates the additive into the polymer before migration to the surface occurs after cooling. This process, often called blooming, occurs because the amide molecule is partially incompatible with the polymer matrix. Once on the surface, the molecules form a thin lubricating layer that interferes with the molecular forces responsible for friction.
Because erucamide has a higher molecular weight and lower vapor pressure than other common slip agents, it is often preferred for applications involving high processing temperatures or long storage periods.
Performance Variable
High ambient temperatures accelerate the migration speed and can lead to an excess of additive on the film surface. If the concentration of erucamide becomes too high, it may interfere with the adhesion of printing inks or the strength of heat seals. Formulations must balance the need for slip with the requirements for downstream converting and optical clarity.