Equipment structure
The structure of the UV weathering box is a stainless steel inner box with two rows of four lamps installed to simulate ultraviolet light. The humidification system is used to increase the temperature of the inner box to simulate a humid environment, and the spray system is used to simulate rain. The three different environments are set to cycle alternately through the program.
Standards
- - GB/T 14522-93
- - ASTM G 154
- - ISO 4892-1
- - ISO 11507
- - ASTMD 4329
Product Usage
TL-UV series UV weathering chambers can simulate the damage caused by sunlight, rain, and dew. UV uses fluorescent ultraviolet UV lamps to simulate the effect of sunlight, and uses condensed moisture to simulate rain and dew. The tested materials are placed in a cycle of alternating light and moisture at a certain temperature for testing. UV can reproduce the damage that occurs outdoors for months to years in a few days or weeks. The types of damage include: fading, discoloration, loss of gloss, chalking, cracking, turbidity, bubbles, brittleness, strength decay and oxidation. UV test data can help you choose new materials and evaluate how changes in formulations affect the durability of new products.
Widely used in coatings, inks, paints, resins, plastics, rubber, printing and packaging, aluminum profiles, adhesives, automobile and motorcycle industries, cosmetics, metals, electronics, electroplating, medicine, etc.
Test equipment
1. The structure of the test chamber is made of corrosion-resistant metal materials and contains 8 fluorescent UV lamps, a water tray, a test sample rack, and a temperature and time control system and indicator.
2. The lamp power is 40W and the lamp length is 1200mm. The uniform working area of the test chamber is 1140×500mm.
3. The lamps are installed in two rows of four, with the lamp tubes of each row installed in parallel and the center distance of the lamps being 70 mm.
4. The test sample is fixedly installed at a position 50mm away from the nearest parallel surface of the lamp surface. The test sample and its bracket constitute the inner wall of the box, and their backs are exposed to the cooling air at room temperature. Due to the temperature difference between the test sample and the air in the box, the condensation stage on the surface of the test sample produces stable condensation conditions. The test box should generate natural air convection from the bottom through the outer wall of the box and the channel of the test sample.
5. Water vapor is generated by the water pan at the bottom of the heating box. The water depth is no more than 25 mm and there is an automatic water supply controller. The water pan should be cleaned regularly to prevent scale formation.
6. The temperature of the test chamber is measured by a sensor fixed on a black aluminum plate (blackboard) with a width of 75 mm, a height of 100 mm, and a thickness of 2.5 mm. The blackboard should be placed in the center of the exposure test. The measurement range of the thermometer is 30-80°C, with a tolerance of ±1°C. The control of the illumination and condensation stages should be carried out separately, and the condensation stage is controlled by the heating water temperature.
7. The test box should be placed in a test room with a temperature of 15-35℃, 300mm away from the wall, and should be protected from the influence of other heat sources. The air in the test room should not be circulated strongly to avoid affecting the lighting and condensation conditions.
Test conditions
1. The test sample is fixed on the test rack, facing the fluorescent light. When the sample rack is not filled with the sample, it is necessary to fill the sample rack with a blackboard to keep the inner wall of the test chamber closed.
2. Test temperature: Three temperatures can be used during illumination: 50, 60, and 70°C, with 60°C being the preferred temperature. The temperature during the condensation stage is 50°C, and the temperature tolerance uniformity is ±2.
4. The cycle of illumination and condensation can be selected as 4 hours illumination, 4 hours condensation or 8 hours illumination, 4 hours condensation.
After the first illumination of 400-450 hours, one fluorescent lamp in each row of lamps needs to be replaced, and the other lamps are cycled and replaced to compensate for the loss caused by lamp aging. This operation mode ensures that the service life of each lamp is about 1600 hours.
5. When replacing the lamp, wipe the water tray dry and clean it to avoid scale formation.
Test samples and performance evaluation
1. Appearance evaluation: The main evaluation for coatings is appearance. Plastics and rubber can also be evaluated when necessary. The main items to be checked are gloss, color change, powdering, spots, blistering, cracks, and dimensional stability. Quantitative items should be tested with instruments, such as gloss and colorimeter.
2. Evaluation of mechanical and other properties: Generally, rubber materials are tested for tensile strength, elongation, and hardness; plastics are tested for impact strength, elongation at break, tensile strength, and flexural strength. Other performance test items may be specified if necessary.
