PVC/Acrylic Alloy Capstock
Understanding UV Resistance and Weatherability
Aurora Plastics is a dynamic and innovative company known for producing the highest quality PVC compounds in both powder and pellet form. Our compounds perform consistently and reliably in a variety of applications.Our AuroraShield™ line of PVC/acrylic alloy capstocks are highly weatherable, pelletized compounds designed for exterior applications such as fencing, siding, decking, arbors/pergolas, windows and doors. AuroraShield™ PVC/Acrylic alloys exhibit excellent weathering stability and resistance to water whitening. A major additional benefit is that AuroraShield™ products possess superior processability attributes.
UV Resistance and Weatherability Defined
UV resistance represents the ability of a material to resist ultraviolet (UV) light present in sunlight. UV light, or sunlight, will cause non-resistant materials and surfaces to fade, discolor and degrade unprotected materials. Weatherability is the way that a material endures or resists exposure to weather. This encompasses moisture as well as temperature, UV and radiation.
Measuring UV Resistance and Weatherability
QUV Accelerated Weathering Tests are performed utilizing specially designed equipment. The test chamber simulates the effects of moisture and (UV) sunlight on a polymer over a given period of exposure. The QUV testing equipment can provide results in a much shorter period of time than actual outdoor weathering and attempts to replicate what can happen to materials over several months or years in actual outdoor environments.
Aurora Plastics utilizes equipment that not only tests materials to help improve quality and durability, but also allows us to create new products based on customers’ unmet needs. The test materials are exposed to alternating cycles of UV light (utilizing specialized UVA-340 lamps) and moisture at measured elevated temperatures. These specialized lamps accurately replicate the short-wave UV energy created by sunlight that can damage polymers.
Many might ask, “What is pass/fail for the tested materials?” Change in color on the material samples is measured by delta E*. Delta E* is a numerical value measuring color differential. The smallest value that the human eye can see is a delta E* of 1.0.
Aurora Plastics has dedicated research and development efforts to focus on unmet needs in the marketplace, particularly as it pertains to weathering and UV resistance of dark color exterior polymers. As a result, we consistently bring leading material technology to market in weatherable and UV-resistant polymers for exterior applications.
AuroraShield™ 4005 series of PVC/Acrylic alloys exhibit excellent accelerated weathering stability and resistance to water whitening as indicated in the following chart:
||Delta – E* (Color Change)
||AAMA One Year Study Results† Arizona/Ohio/Florida
|Delta – E* (Color Change)
|Water Whitening: 0.43
|AAMA One Year Study Results† Arizona/Ohio/Florida: 0.88/0.52/1.37
|Color: Medium Brown
|Water Whitening: 0.85
|AAMA One Year Study Results† Arizona/Ohio/Florida: 1.33/1.80/0.97
|Color: Light Brown
|Water Whitening: 0.24
|AAMA One Year Study Results† Arizona/Ohio/Florida: 0.18/0.51/0.34
†QUV Test time is 3,000 hours with the following cycle and conditions: AAMA (American Architectural Manufacturers Association) consists of samples placed in exterior environment in Arizona, Ohio, and Florida. The following test samples represent a control color material (center), a leading ASA capstock material (right), and Aurora Plastics PVC/Acrylic alloy capstock (left) after 3,000 hours of testing time:
delta E* of 0.55
Control Sample Prior
delta E* of 15.22
Water resting on a horizontal surface at elevated temperatures, known as water submersion, may result in some whitening which is more apparent in darker colored surfaces. Aurora Plastics uses accelerated testing methods to compare product performance and utilizes this data, in addition to traditional QUV tests, to develop high performance compounds for the variety of weather and real world environmental conditions.
Aurora Plastics has the ability to custom color match compounds with L*a*b* values.