Compounding Creativity with Technology
Color trends have varied over the years, but white seems to never go out of style. Whether its shades of white, or finishes, white railing, fence and windows remain the predominant color for these outdoor applications.
As end customers have spent more for these products as of late, they are asking more of their performance in terms of consistency of overall appearance (shade and gloss), inherent physical properties such as scratch or abrasion, or long-term resistance to color change and fading. With performance expectations rising, it becomes that much more critical to have a high-performing white compound that delivers and, to that end, new enhanced grades of PVC have done just that for capstocking building products.
Available in a range of finishes, from matte to high gloss, the customer can select the desired finish for the application, all while knowing the performance exceeds that of conventional white PVC compounds. Depending on the application, like railing, post sleeves or spindles, non-chalking grades are available. Chalking grades for windows and fence applications are suggested for added UV protection (the surface of the part will exhibit a “chalk” like effect for added protection against UV rays.) Teknor Apex capstock materials show significant improvements to reduce yellowing by as much as 1-2 units compared to conventional grades (tested via accelerated weathering.)
We rigorously test new capstock grades – in four geographic locations (FL, AZ and OH in addition to Xenon, QUV and environmental chamber testing. On top of outdoor and accelerated weathering, we perform a battery of physical property tests, including tensile and flexural strength and modulus, impact strength, scratch and abrasion resistance. This testing is performed to help our customers make informed decisions regarding expected long-term performance and to help alleviate the burden of some of their own internal testing.
Figure 1 below compares the shift in color or Delta E (DE) over two years when exposed to a Florida environment. The higher the DE value, the greater the shift in overall color. An initial shift of colorto the blue side is not uncommon, but ultimately returns back towards the control or slightly yellow. This would explain why the curves have an initial upward trend, and then shift downward. In each case, the enhanced formulation results in a lower color shift (DE) as compared to the conventional white capstock.
Figure 1: 24 months exposure in Florida-chalking grades
Figure 2 shows the same comparison as Figure 1 but using non-chalking technology. As one might expect, the performance of color retention is not as good as the chalking grades, however the enhanced white formulations remain significantly better in terms of overall color retention. Non-chalking grades would be used in applications where the profile would be touched, leaned against or in some way, in contact with the consumer, and would not leave a white residue (porch railings, spindles, columns, etc).
Figure 2: 24 months exposure in Florida (Non-chalking grades)
Finally, in Figure 3, a similar comparison is made using accelerated weathering (QUV), evaluating enhanced and conventional formulations, with chalking and non-chalking grades of white.
Accelerated QUV Weathering
Figure 3: QUV conditions follow ASTM G154 Cycle 1. Color Measurements were taken with specular included D65-10°
In short, PVC compounds in various shades and gloss levels of white stand the test of time better than ever. This helps outdoor building products manufacturers produce cost-effective profiles, potentially allowing for the use of recycled content, without sacrificing the long-term appearance of the end product. The data provided here is a sample of the type of information Teknor Apex provides its customers as they work toward designing and developing products for outdoor use. And if other colors are required, Teknor offers a complete line of high-performance alloy capstocks, for medium and dark colors, and an extensive weathering database to demonstrate long-term performance.
With the ever-growing demand for better outdoor living experiences, these capstocks provide for a more striking aesthetic while providing the low maintenance that creates high levels of customer satisfaction.
Contact us to learn more about the custom color match and finishes that round out your portfolio.
