Introduction
TOPAS® COC, a high-Tg amorphous polyolefin copolymer, can be used as an anti-block in LLDPE films. The glass transition temperatures of COC resins mean that at typical use conditions the COC phase is still a glassy solid. The hard COC domains function as an anti-block while also adding to the stiffness, heat seal strength, and hot tack of the film.
Formulations
Three, 50µm films were produced for this study; their formulations are below.
Results and Analysis
The use of 20% COC in DOWLEX 2045 resulted in reductions in relative coefficient of friction (COF) and increases in relative haze.
The Relative COF is the ratio of the Static COF values of the blend and the control films. A lower Relative COF for a blend means that it has a lower COF. Similarly for Relative Haze, a lower Relative Haze would mean that the sample film has a lower haze value than the control.
The addition of 20% 8007F-04 into DOWLEX 2045 resulted in a significant reduction in COF, but also a 3x increase in the haze value of the film. The haze increase could likely be mitigated by using a thinner layer in a coextruded film setup. The coextruded film approach is ideal because the surface property of COF can be changed even with a thin layer.
Secondary Benefits of TOPAS COC Addition
As shown in other entries in Performance Data, adding COC to LLDPE increases film stiffness, enhances easy tear, and improves hot tack.
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