How much do you know about light aging tests?

What Are Light Aging Tests?

Light aging tests evaluate how materials degrade under prolonged exposure to light and environmental factors. Traditional natural exposure tests are time-consuming, so artificial accelerated aging tests are widely adopted. These tests simulate and intensify the damaging effects of natural outdoor climates (e.g., light, heat, oxygen, and ozone) to rapidly assess material performance. By accelerating the aging process, manufacturers can improve product quality, enhance weather resistance, and minimize losses caused by degradation.

Types of Light Aging Tests

Artificial light aging tests primarily include three categories: carbon-arc lamp aging, UV lamp aging, and xenon-arc lamp aging.

1. Carbon-Arc Lamp Aging Test

Principle: Carbon-arc lamps generate light through an electric arc between two carbon electrodes. Two variants exist:

Enclosed carbon-arc lamps: Initially used for textile lightfastness testing.

Sunlight carbon-arc lamps: Originally designed for coating light resistance evaluation.

Limitations: High maintenance costs, narrow spectral range, and difficulty in calibration have led to their gradual phase-out.

2. UV Lamp (UV) Aging Test

Principle: UV lamps simulate sunlight to accelerate material degradation. Common subtypes include:

UVA-340: Closely matches natural sunlight’s UV spectrum, ideal for simulating outdoor aging.

UVA-351: Mimics UV radiation filtered through window glass, suitable for indoor product testing.

UVB-313: Emits stronger UV radiation than natural sunlight, used for rapid durability testing.

Applications: Suitable for non-metallic materials (e.g., coatings, paints, rubbers, plastics).

3. Xenon-Arc Lamp Aging Test

Principle: Xenon-arc lamps emit broadband light (300–800 nm), including UV, visible, and short-wave infrared radiation. Filters modify the spectral output to match specific environmental conditions:

Daylight filters: Simulate unfiltered sunlight.

Window glass filters: Replicate indoor light exposure.

UV-enhanced filters: Intensify UV radiation for accelerated testing.

Cooling Systems: Water-cooled or air-cooled systems regulate lamp temperature.

Applications: Widely used for plastics, rubbers, coatings, dyes, pigments, and textiles.

Key Considerations for Testing

Acceleration Factors: No universal formula exists to correlate laboratory aging rates with real-world exposure. Testing cycles are negotiated based on material type, application, and environmental conditions.

Parameter Configuration:

With Standards: Follow prescribed protocols (e.g., ISO, ASTM).

Without Standards: Clients must specify parameters:

Light source type (e.g., UVA-340. xenon-arc).

Irradiance, filter type, temperature, humidity, and spray cycles.

Conclusion

Light aging tests are indispensable for evaluating material durability and ensuring product reliability. By selecting appropriate test methods and parameters, manufacturers can optimize product performance, reduce time-to-market, and enhance competitiveness in diverse industries.

Note: This article summarizes technical details for educational purposes. For specific testing requirements, consult relevant standards or certified laboratories.