Ultraviolet radiation not only harms the human body, but also poses significant risks to products! During the processing, storage, or use of materials or products, due to external factors such as heat, light, oxygen, mechanical stress, ozone, harmful metal ions, radiation, etc., physical or chemical changes occur inside the material, resulting in performance degradation and gradually losing its value for use.
The types of damage caused by ultraviolet radiation include fading, loss of luster, powdering, cracking, cracking, blurring, foaming, brittleness, reduced strength, and oxidation.
The range of product fields involved is also very broad, such as rubber, plastic and its products, coatings, paints, dyes, fabrics, printing and packaging, adhesives, metals, electronics, electroplating, cosmetics, etc.
The ultraviolet rays in sunlight are the main cause of product photodegradation and photoaging, because the shorter the wavelength, the higher the energy, and the stronger the penetration ability. In the solar spectrum (as shown in the figure below), ultraviolet radiation has a shorter wavelength. At this time, the lifespan of the product can often be evaluated through ultraviolet aging tests to ensure its quality.
UV aging test is a testing method for evaluating the UV resistance of new materials, usually conducted in a laboratory through a UV accelerated aging test chamber. Within just a few weeks or months, reproducible and reliable aging test data can be obtained through UV aging testing; Its short wavelength ultraviolet light irradiation and condensation cycle system can realistically simulate the destructive effects of sunlight, dew, and rainwater on materials.
The UV aging test mainly simulates the degradation effect of ultraviolet light in sunlight on the product.
At the same time, it can also reproduce the damage caused by rainwater and dew;
Conducting experiments by exposing the tested material to controlled cycles of sunlight and moisture, while increasing the temperature; Using ultraviolet fluorescent lamps to simulate sunlight, and also simulating moisture effects through condensation or spraying.
Common types of UV lamps
UVA-340 simulates the ultraviolet part of sunlight and is mainly used for photo aging testing of outdoor products;
UVA-351 simulates the ultraviolet portion of sunlight passing through window glass and is mainly used for indoor product photoaging testing;
UVB-313EL: Widely used for rapid and time-saving testing of durable materials, it accelerates material aging and sometimes leads to abnormal results. Customer consent must be obtained before use.
Let's give a simple example of UV aging test below to help everyone better understand the experiment:
A UV aging test case was conducted in the laboratory: the customer submitted several samples of a certain PVC material for use as window glass film, and UV aging tests were required to verify the reliability of the product.
Testing environment: ambient temperature 24.2 ℃, humidity 53% R.H
Testing Standard: ASTM G-154-2016 Test Method for Non Metallic Materials Exposed to Ultraviolet Light in Fluorescent Devices
Testing method:
Irradiance: 0.89W/m; Wavelength: 340nm; Exposure period: (60 ± 3 ℃) UV irradiation for 8 hours at black panel temperature;
Condensing for 4 hours at a black panel temperature of (50 ± 3 ℃);
Duration: 100 hours;
Part of the sample is wrapped in aluminum foil, while the other part is exposed outside. After testing, perform a gray card test on the wrapped and exposed areas to evaluate the gray card rating.
The results showed that after the experiment, there was no significant color change on the surface of the sample, which meets the reliability requirements under standard conditions.
The ability of a product to withstand solar radiation and its effects outdoors without shading can be evaluated through UV aging tests. Experimental parameters: temperature, humidity, lamp type wavelength, radiation intensity, light dark period, duration.
Later, due to the many standards for UV aging testing, many of which are specific to a particular product category, we have extended and summarized some general standards for your reference:
Partial General Standards for UV Aging Test
ISO 4892-3 Plastic Laboratory Light Source Exposure Test Method Part 3 Fluorescent UV Lamp
GBT 16422.3 Plastic Laboratory Light Source Exposure Test Method Part 3 Fluorescent UV Lamp
ASTM G-151 Standard Test Method for Exposure of Non Metallic Materials to Accelerated Testing Equipment Using Laboratory Light Sources
ASTM G-154 Standard Test Method for Non Metallic Materials Exposed to Ultraviolet Light in Fluorescent Devices
British Standard BS 2782: Part 5, Method 540B (Exposure to Laboratory Light Sources)
SAE J2020 Accelerated Exposure Testing of Automotive Exterior Components Using Fluorescent UV/Condensation Equipment
ASTM D4587 Cycle 4 Coatings and Related Coatings Fluorescent UV Condensation Exposure Procedure