Meaning
Chemical breakdown of surface-migrating lubricants occurring when polymer melts are exposed to excessive thermal energy or atmospheric oxygen. This process primarily affects erucamide or oleamide additives used to reduce the coefficient of friction in polyolefin films. When slip agent oxidation occurs, the clear film often develops a yellow tint or a burnt odor.
These degraded molecules lose their ability to migrate to the surface, causing the film to become tacky and difficult to unwind.
Degradation Pathway
High melt temperatures in the extruder barrel accelerate the reaction between oxygen and the unsaturated bonds in the amide. This changes the chemical structure of the lubricant, turning it into a non-functional byproduct. Excessive residence time in the machine further increases the damage to the additive package.
Surface Performance
Yellowing of the finished product is the most common visual indicator of a failure. A film that should be slippery instead grabs the metal rollers of the packaging machine. This defect leads to jams and lost production time during the conversion process.
Production Cost
Maintaining a low melt temperature is required to preserve the integrity of the slip agent. If the resin is overheated, the cost of the lost material and the machine downtime exceeds any savings from faster cycle times. Stable processing conditions are necessary to maintain the coefficient of friction within the specified range.
