Antiblocks for Blown Film

Blocking is an undesirable attraction between adjacent layers of film or sheet, often making it difficult to the separate individual layers. Certain polymers including, polyolefins and polyesters have an inherent tendency to block.

Blocking can occur during extrusion, conversion processes or during storage. Blocking can reduce packing efficiencies on automated and manual packing lines as it causes for example bags to be more difficult to open and stacks of thermoformed trays harder to separate.

The introduction of an antiblocking agent into a polymer will reduce the blocking tendency allowing films or sheets to be easily separated. The antiblocking agent will create a microscopic roughening of the film or sheet surface which reduces the available contact area between adjacent layers.