Page 69 - Plastics News March 2025
P. 69
PRODUCT NEWS
These produce micro-roughness on the surface achieve the best packaging performance.
that allows air to enter between the films in con-
tact, easing their separation. It is important to Most of the polyethylene resins used in film ex-
note that anti-blocks are not migratory, and only trusion for flexible packaging contain slip and
the particles that protrude from the film surface anti-blocking additives. However, evaluating the
contribute to their functionality. need to use masterbatch additives to achieve
the best packaging performance is crucial.
Anti-slip Additives
Certain applications require stacking packages
during storage, transport, or display, so manu-
facturers increase the outer layer’s COF us-
ing anti-slip additives. These can increase the
stickiness of the surface (smooth finish anti-slip)
Size and shape of main inorganic anti-block. or produce roughness. Usually, the goal is to
Courtesy of Ampacet Corporation. achieve a static COF greater than 0.45. It is im-
portant to note that using resins with migratory
Some commonly used anti-blocking compounds slip additives interferes with the anti-slip effect,
are talc, natural silica, and synthetic silica. Nat- generating an antagonistic effect.
ural silica (or diatomaceous earth/DE) and talc
are the most efficient anti-blocking compounds, Resins without slip additives produce high COF
given their irregular shapes. levels, but most applications require a low COF
on the inner sealing layer and a high COF on the
Organic Antiblocking Compounds
outer side. Manufacturers use slip additives to
There are also organic antiblocking compounds achieve this balance.
that can function as slip additives.
In conclusion, smart use of slip, anti-slip, and
anti-block additives is important for producing
high-performance flexible packaging.
Source – Plastics Engineering
This graph compares blocking force of mineral
antiblock vs level in ppm. Courtesy of Ampacet
Corporation.
Slip and anti-blocking additives have a synergis-
tic effect, so they are typically used together to
March 2025 PLASTICS NEWS 69
