Page 67 - Plastics News March 2025
P. 67
PRODUCT NEWS
Modifying the Slip of Plastic
Films with Additives
Although there is no consensus on COF levels,
in practice the following values are usually taken
as reference:
Low COF ≤0.20
Medium COF 0.20-0.40
High COF >0.40
Plastic film’s slip and friction characteristics are
essential for optimal performance in flexible
packaging. Modifying these characteristics with
additives can greatly benefit manufacturers.
The slip and friction of plastic films are essential
properties that help achieve adequate function- A typical slip measurement device for plastic
ality in flexible packaging. films. Courtesy of The effect of polyolefin for-
mulation and processing variables on slip agent
The COF and blocking force affect material flow, performance.
package opening, and stack stability. These are
critical factors in the converting, filling, storage, The film’s external surface usually has a slightly
transportation, and distribution. higher COF than the inside (sealing), generating
a higher level of friction.
Slip Additives
The most used slip additives are based on fatty
These additives lower the COF (Coefficient of
Friction) by modifying the films’ surface. A low acid amides, such as erucamide, which migrate
COF is indispensable for proper material flow to the surface, forming an oily layer that reduces
over converting and packaging machines’ rollers friction. These additives have an excellent cost-
and metal surfaces (FFS machines). benefit balance; however, the speed and direc-
tion of migration are quite variable. Resins with-
March 2025 PLASTICS NEWS 67
