Outdoor Weathering Performance
Solar radiation has a particularly harmful effect upon polymeric materials initiating degradation by causing superficial surface crazing. These crazes become sites for further erosion from water, dust, chemicals, etc. The degree to which these conditions affect the polymer depend largely upon environmental parameters such as geographical location, altitude, seasonal variations, etc.
Coxwell Thermoclear sheet has on one or both sides proprietary UV-protected surface, giving excellent resistance to outdoor weathering. This unique protection ensures long-term optical quality under intensive UV exposure, and maintains the superior toughness of the polycarbonate material in comparison to other thermoplastic glazing.
Typical Values of Thermoclear Sheet
Research into the long-term effects of weathering on glazing materials is basically focused upon measuring product performance through material property changes, typically mechanical strength, impact resistance, colour retention, transparency, etc.
Under ISO 4892, a test has been developed using high intensity Xenon lamps to simulate natural sunlight. Together with UV filters and programmable rain cycles, the test is able to simulate natural conditions.
Accelerated weathering tests have been carried out on Coxwell Thermoclear sheet by GE Structured Products. Using in-house Xenon 1200 apparatus, these tests were carried out according to ISO 4892. However, even tougher demands were placed on the material by removing the UV filter for 1/6 of the cycle. Placed within this environment, Coxwell Thermoclear sheet was exposed to 5,000 hours. Experience with the Xenon test equipment indicates that this relates to 15 years’ natural exposure in a moderate European climate. Following the test the optical properties of light transmission and yellowness index were measured and compared with an un-aged sample.
* WARRANTY :
Offers a Ten Year Limited Warranty on Coxwell Thermoclear sheet covering discolouration, loss of light transmission and loss of impact strength due to weathering as more specifically defined in such warranty. Please consult your local distributor or GE Structured Products Sales Office for more details.