The waterproof process of raw luminous powder usually adopts the chemical coating technology. The core process is: mix native solvent based particles with specific formulated chemical solution sufficiently, and form a dense protective film layer on the surface of the particles through chemical reaction.

After the react chemically, a protective film will be formed on the surface of the particles. This protective film is like a “raincoat” for the luminous particles, which can effectively isolate the particles from water and prevent water from penetrating into the particles, thereby ensuring that the luminous powder can maintain their original luminous effect even if they contact with water.

However, due to the different formulas used by different manufacturers, the waterproof strength also varies. Especially in harsh environments such as seawater immersion, hot water contact or long-term humidity, their glowing performance will differ considerably.

• Mixing with water-based medium:

During the production process, it needs to be mixed with various water-based medium such as water-based paint, water-based ink, water-based resin and water-based glue etc.

• High humidity environment:

The final product needs to be exposed to high humidity for a long time, such as outdoor luminous street signs used in areas with frequent rain and humid air.

• High-intensity impact:

The final product will be subjected to high-intensity impact, such as when tableware with luminous printed patterns is washed in a dishwasher.

• High-temperature hot water treatment:

The final product needs to be subjected to high-temperature hot water treatment, such as when the fabric is in dying and washing process.

• Contact with slightly corrosive liquids:

The final product needs to be in contact with slightly corrosive liquids for a long time, such as the marine luminous safety signs used on the vessel, which will frequently contact with seawater.

Using PH testing paper is the simplest and the quickest way to check the changes.

Put the waterproof luminous powder into water, and immerse PH paper. At this time, the test paper should show it as neutral. After soaking for a period of time, put another PH paper again. If the paper color changes, it means that the water has penetrated into the luminous powder through the waterproof coating, and the waterproof performance has been damaged. If there is no color change, the waterproof performance is still intact.

Our waterproof technology owns a Japanese patent. Customer cases are as following:

• Water or humidity resistance:

Even if it is mixed into water-based medium for years, or in a high humidity environment for a long time, its luminous performance remains stable. A Brazil customer use our waterproof luminous powder for outdoor luminous street signs, which can maintain good luminous effects after continuous use for 8 years in an environment with frequent rainfall and humid air.

• High-pressure impact resistance:

It can withstand the impact of high-pressure water flow generated by equipment such as dishwashers. An American customer did a test. After being washed in a dishwasher with an intensity of about 50kPa and a duration of about 2 hours, tableware printed with luminous patterns was not affected. Their luminous brightness was unchanged.

• High temperature resistance:

Reliable performance in high temperature environment. In an Indian project, when the fabrics with luminous printing patterns were washed with 80-100℃ water, it could still maintain stable luminous performance.

• Slight acid and alkali resistance:

It can resist to slightly corrosive liquids. Taking the Chinese marine luminous safety signs as an example. The signs made of waterproof luminous powder can still keep a good luminous effect after being immersed in seawater (weakly alkaline) for 3-4 years.

Luminous powder usually needs to be mixed with a certain transparent liquid medium (such as paint, ink, etc.), then it will be applied to the terminal product as a whole luminous coating. In addition to the waterproof performance, the quality of the transparent medium is also an important influencing factor:

• The adhesion of the medium:

If the adhesion of the medium itself is poor, when it is subjected to external forces such as friction, washing or extrusion, the whole luminous coating will peel off from the surface of the product. For example, if the ink adhesion is weak, the entire luminous ink pattern may fall off quickly after washes, so that the printed part will be gone and will not glow.

• Transparency of the medium:
  The transparency of the mixed medium will also affect the luminous effect. The higher the transparency, the better the luminous effect, the longer the transparency is maintained, and the longer the service life of the luminous material. If after a period of time, the medium itself produces impurities, the transparency will decrease, then the luminous effect will also become weaker.
  Therefore, we recommend choosing inks or paints with high transparency and strong adhesion, so that a good luminous effect can be maintained for a long time.