Why do we need aging testing?

Weather and sunlight exposure are the leading causes of damage to coatings, plastics, inks and other polymers, causing billions of dollars in economic losses each year due to light and moisture damage to materials. Such damage includes loss of gloss, fading, yellowing, cracking, peeling, embrittlement, loss of strength and delamination.

Even indoor light and sunlight coming through glass windows can cause some materials to deteriorate, for example causing pigments, dyes, etc. to fade or change color. Obviously, aging resistance and light stability are important for many products. Various methods have been used over the years.

Most researchers now use the natural exposure method for testing, which has many advantages: it is practical, cheap and easy to perform. However, most manufacturers are unwilling to wait years to see if a new and improved product design is actually an improvement. The principle of the xenon weathering Test Chamber is that for durable materials, short-wavelength ultraviolet rays can cause significant aging damage. A xenon Tester simulates the full spectrum of sunlight, including ultraviolet, visible, and infrared).

Natural factors that cause product aging

Greater aging damage is caused by three factors: light, heat and moisture.

Any of these three factors can contribute to material degradation. Together, they often cause more damage than any one of these factors alone.

Light

Different materials have different sensitivities to light. For durable materials, such as most paints and plastics, short-wavelength UV light is responsible for the aging of most polymers. However, for less durable materials, such as some pigments and dyes, long-wavelength UV or even visible light can cause severe aging.

high temperature

As the temperature rises, so does the damaging effect of light. While temperature does not affect primary photodamage responses, it does affect secondary chemical reactions. Laboratory aging tests need to provide accurate temperature control, and the aging process is often accelerated by increasing the temperature.

humidity

Dew, rain, and high humidity are the main causes of moisture hazards. Our research shows that items placed outdoors are exposed to humidity for extended periods of time each day (8 to 12 hours per day on average).

humidity

The study also found that dew from moisture was a major contributor to outdoor humidity. Dew can do more damage than rain because it sticks to the material longer and causes more moisture absorption. Of course, rainwater is also very harmful to materials. Rain can cause thermal shock, for example, when a car is on a hot summer day, the temperature suddenly rises due to rain showers and a sudden drop in temperature, creating a shocking phenomenon.

The mechanical erosion caused by rain will also accelerate the aging of materials, such as wood coatings. Rain washing can remove the aging layer on the surface, and will not age the inner layer to cause further aging when exposed to sunlight. For interior materials, the main effect of moisture is usually mechanical stress. This is caused by the material trying to maintain a moisture balance with the surrounding environment. The more moisture a material is subjected to, the greater the pressure to overcome.

Although indoor items such as textiles are only exposed to moisture, moisture is still a significant factor in the deterioration of outdoor materials. Outside, the relative humidity (RH) of the surroundings can affect how quickly wet materials dry.