I am presently dealing with an application that involves PET bottles. The problem is the physical characteristics of the bottle tend to change over time. Bottles tested earlier in the year,that had set in unopened bulk packaged cartons showed no signs of tackiness, however fresh bottles, less then a few days old, are extremely tacky and will not run on the newly purchased machine. However these same bottles left exposed to the atmosphere will after only a few days lose most of their tackiness.
I am aware of treating the bottles with an anti-stat agent to eliminate the static charge on the bottles and I am also aware that this can also act as a lubricant to minimize the tackiness of the bottles. My questions are
1) What causes this tackiness?
2) Can it be eliminated instead of controlled and if so, how?