PC Hollow Sheet is widely used in greenhouses, buildings, carports and other light-transmitting roof structures thanks to its excellent light transmittance. However, many users find that after only a few years, PC Hollow Sheet will turn brittle, yellow and age, with declining light transmission and faded appearance.
Full replacement would cost a substantial amount, while continuing to use deteriorated sheets leads to unsatisfactory performance. This article analyzes the root causes behind yellowing of PC Hollow Sheet and shares effective prevention solutions.
Cause 1: Raw Material Quality
The core factor lies in raw materials, and price usually reflects quality. Low-cost PC Hollow Sheet products are mostly manufactured with domestic raw materials or recycled regrind, while high-quality versions adopt brand-new imported PC pellets, resulting in obvious gaps in durability and anti-aging performance. Premium sheets have far lower risks of yellowing and aging, as well as a much longer service life.
Cause 2: UV Coating Technology
The long service life of qualified PC Hollow Sheet mainly relies on a critical production process: UV anti-ultraviolet coating. This layer effectively blocks ultraviolet radiation and prevents yellowing and aging of PC substrates.
10,000-Hour Accelerated Aging Lab Test
A 14-month continuous xenon lamp weathering test was conducted on standard transparent double-layer 6mm PC Hollow Sheet. The test result outperformed industry benchmarks:
- Industry standard requirement: Yellow index ≤ 3 after 2,000 hours of aging
- Test result: Yellow index of 2.5 after 2,000 hours
- Light transmittance retained at 70% after 10,000 hours of accelerated aging
Conversion Reference for Xenon Lamp Test Hours vs. Actual Outdoor Exposure
A general reference ratio is provided: 500 hours of xenon lamp testing equals approximately one year of real outdoor service.
There is no unified global standard conversion formula between accelerated test hours and actual outdoor years. Annual ultraviolet radiation, temperature and humidity vary drastically across regions and years, making fixed conversion coefficients unfeasible.
Cause 3: Incorrect Installation Methods
Improper installation is a common mistake made by most users. Most commercial PC Hollow Sheets are single-sided UV coated. During installation, the UV-coated surface must face direct sunlight. If installed backwards, the sheet loses its ultraviolet protection layer and will rapidly yellow and turn brittle under UV exposure, drastically shortening its usable life and reducing light transmission.
