Palram PALGAR - Manual (Page 11)

PALSUN® PALGARD™
Glazing Guide
11
9. Durability under Environmental & Climatic Conditions:
The UV segment of the Solar radiation is destructive and harmful to most plastics & polymers.
The extent of crazing, deterioration of external surface & final disintegration depends on type of polymer
and duration of exposure.
Further damage and accelerated deterioration might be caused by environmental aspects such as ice,
water & humidity, extreme temperature changes, strong winds with dust and sand particles, air &
chemical pollution etc. Amount of damage depend on location, height (above sea level and relative to
near surroundings) climate conditions, air pollution level & nature etc.
A typical & easily recognizable sign of deterioration is substantial yellowing followed by significant
transparency loss, surface roughness & shallow crazing. Such deterioration also indicated a serious drop
in strength and impact resistance.
PALSUN and PALGARD of all types are UV shielded by an integral co-extruded UV protective layer, on one
(external) or both sides (for outdoors applications), providing long-term safeguard against UV
deterioration. Both sheets are inherently resistant to extreme weather condition s most environmental
circumstances. PALGARD has a few more enhanced attributes as mentioned in page 7.
QUV Laboratory tests (accelerated UV exposure) made according to ASTM E-58 (88) US Standards show
that after 2,000 h of accelerated exposure, equal to 20 years of normal exposure to intensive solar
radiation at hot & sunny climates, there was an almost negligible reduction in light transmission and
minimal decrease in physical properties.
All the above assure product longevity and years of service. PALSUN and PALGARD will keep their look,
strength & optical quality for many years of service, under extreme conditions and intensive exposure to
direct sunlight with the minimal reduction of physical properties.
Following graphs show influence of said QUV tests on unprotected polycarbonate sheet Vs PALSUN.
Graph 3. Change in % Light Transmission
as a Result of QUV Exposure Hours
(PALTUF
- flat solid polycarbonate sheet for
indoors use)
Graph 4. Change in Yellowness Index
as a Result of QUV Exposure Hours