Surface Treatment in Packaging Applications
TOPAS® Cyclic Olefin Copolymer (COC) has a naturally low surface energy due to its nature as a polyolefin, like polyethylene (PE) or polypropylene (PP). The surface energy of TOPAS is essentially identical to that of PE and PP prior to treatment. COC can be surface treated like other olefins, using standard technologies such as corona, plasma or flame. The table below has example surface energies for some untreated materials:
Where COC differentiates itself from PE and PP is the surface energy level that can be achieved with surface treatment and the longevity of the surface energy. COC can be raised to a surface energy 50dyn/cm or more with a corona treater power density of 10W/min/m2. By comparison, it can take more than 40W/min/m2 to achieve the 50dyn/cm level for PE and PP films. The chart below shows the measured surface energy for four films when treated with different power densities:
As it ages, a treated surface will tend to lose some of the surface energy increases. TOPAS retains the higher surface energy better than PE and PP. This can be observed in the next chart where the same four films had their surface energy measured after aging for 14 days.
Surface Energy in Healthcare Applications
In healthcare, other polymers may have a higher energy surface that can compromise drug storage. Lower surface tension can promote liquid transfer efficiency to maximize drug utility, leaving less active ingredient remaining in the container.
For more information on TOPAS medical plastic for Healthcare, see our Medical Brochure.
For more information on TOPAS resin for Packaging, see our Packaging Brochure.
Consult our general Brochure or our parent company site Polyplastics.com for more general information.