The principle of UV aging test chambers:

The ultraviolet weather resistance test equipment is another type of light aging test equipment that simulates sunlight, mainly simulating ultraviolet light in sunlight.

At the same time, it can also reproduce the damage caused by rainwater and dew. The device conducts the experiment by exposing the material to sunlight and placing it in a controlled interactive cycle of sunlight and moisture, while changing the temperature. The device uses ultraviolet fluorescent lamps to simulate sunlight, and can also simulate the influence of moisture through condensation or spraying.

In just a few days or weeks, the device can reproduce the damage that takes months or years outdoors. The damage caused mainly includes fading, discoloration, decreased brightness, powdering, cracking, blurring, embrittlement, decreased strength, and oxidation.

The test data provided by the equipment is of great help in selecting new materials, improving existing materials, or evaluating changes in the composition that affect product tolerance. The device can predict the changes that the product will encounter outdoors very well.

Although ultraviolet light only accounts for 5% of sunlight, it is the main light factor causing a decrease in the tolerance of outdoor products. This is because the photochemical reaction of sunlight increases with the decrease of wavelength.

Therefore, when simulating the destructive effect of sunlight on the physical properties of materials, it is not necessary to reproduce the entire sunlight spectrum. In most cases, only short wave UV light needs to be simulated. The reason why UV lamps are used in the UV accelerated weathering testing machine is that they are more stable than other lamp tubes and can better reproduce the test results.

The best method is to simulate the impact of sunlight on physical properties, such as brightness reduction, cracking, peeling, etc., using fluorescent UV lamps. There are several different UV lamps to choose from. Most of these UV lamps mainly produce ultraviolet light, rather than visible and infrared light. The main difference between lamps is the total UV energy generated within their respective wavelength ranges.

When the ultraviolet aging test chamber is used for aging test, the sample surface temperature is an important exposure parameter. Generally, high temperature will accelerate the polymer degradation process. The allowable test temperature should be determined according to the tested material and aging performance evaluation index.

Fluorescent ultraviolet lamps emit less infrared than xenon lamps and carbon arc lamps, and the heating effect on the surface of the sample is basically formed by the convection of hot air. Therefore, the temperature difference between the blackboard thermometer, black standard thermometer, sample surface, and exposure chamber air is very small.

The following two exposure methods: exposure methods 1 and 2 correspond to the equipment described in ① and ②, respectively. Customers can also use other methods, but the exposure conditions should be specified in the test conditions.

1. After a period of light exposure, the sample undergoes a cycle test without an irradiator, and the test time is carried out according to relevant standards. If there are no specified cycle conditions, we recommend the following cycle methods:

①. Expose to radiation at a black standard temperature of 60 ℃± 3 ℃ for 4 or 8 hours; Then, expose to non irradiation condensation for 4 hours at a black standard temperature of 50 ℃± 3 ℃; It should be noted that the aging degradation of some polymers (such as PVC) is sensitive to temperature. In this case, it is recommended to use irradiation exposure temperatures below 60 ℃ (such as 50 ℃) to simulate colder climates;

②. When selecting the program of irradiation exposure followed by condensation exposure, the allowable irradiation or condensation exposure time is 2 hours to ensure that the conditions of each exposure period reach equilibrium;

2. After a period of exposure to light, the sample undergoes a cycle test without an irradiator. The sample is subjected to continuous irradiation exposure and periodic water spraying cycle tests, and the test time is carried out according to relevant standards. If there are no specified cycle conditions, we recommend the following cycle methods:

①. Expose to radiation at a black standard temperature of 50 ℃± 3 ℃ and a relative humidity of (10 ± 5)% in the air for 5 hours, then continue to expose to radiation at a black standard temperature of 20 ℃± 3 ℃ and spray water for 1 hour; Attention: In the equipment, the exposed surface of the sample is moistened by condensation through a moisture condensing machine. Moisture is generated by heating water in the container located below the sample holder;

②. When the equipment does not meet the requirements of 1, the method of providing relative humidity in the exposure room or spraying the sample with pure water or simulated acid rain aqueous solution can be adopted;

When conducting tests in the UV test chamber, the exposure method can be selected according to one’s actual test requirements; Different experimental standards use different methods;

Precautions for UV aging test chamber:
1. Because ultraviolet radiation can cause certain harm to the human body, do not directly open the chamber door or look directly at the lit light during the experiment, nor directly expose the skin to the light. It is best not to open the chamber door during the experiment, but if debugging is required during the experiment, it is best to first take protective measures before proceeding.

2. If the sample needs to be tested in the ultraviolet environment for a relatively long time, there may be water shortage during the test process. To ensure accurate test results, it is necessary to regularly check whether the water shortage light on the equipment is on. If it is on, it is best to supplement it in a timely manner.

3. Because the UV aging test chamber is not an explosion-proof and flame proof testing equipment, it is best not to put samples containing flammable and explosive substances into the studio for testing. It is best not to contain corrosive substances in the same sample, otherwise it may cause corrosion on the walls of the test chamber.

UV aging test Chamber is designed for evaluating the resistant performance of non-metallic materials, organic materials (plastics, paints, coatings, rubbers, etc.) under the specified conditions such as sunlight, temperature, and other climatic conditions. It creates a man-made testing environment imitating the natural light source such as sunlight and other damages in the nature, such as rain and dew damage, to impose on the materials and to assess the degree of color changing and fading under the accelerated environment conditions. The chamber fully complies with the requirements of Standard ISO 4892-1, ISO 4892-3, GB/T16585-1996, GB14522-93, GB/T16422.3-1997, ASTMG53 and etc., provides the best UV sunlight simulation, and is easy to use and operate.