Why does the hot-melt marking paint change color

The specific color change of hot-melt marking paint is that the white marking tone turns yellow, while the yellow marking tone turns dark. The consequences not only affect the visual recognition of the marking, but also cause a decrease in adhesion and durability. The reason for this situation is mostly due to the deterioration of organic substances such as resin, titanium dioxide, and other additives in hot melt coatings under high conditions, and the long-term exposure of hot melt coatings to ultraviolet radiation.

It is not difficult to prevent such problems as long as the heating temperature and construction conditions are mastered. The discoloration of hot-melt marking paint can be controlled within the specified quality range. The heating temperature of the marking paint in the hot melt kettle should be between 180 ℃ and 230 ℃. After 5-10 minutes of rotating mixing, the material is applied and scratched. If the temperature is too high or the burning time is too long, the organic substances in the paint will change their characteristics and cause discoloration. This requires careful operation and construction during the heating and construction process.
The products provided by the manufacturer should be made of heat-resistant and cracking resistant materials, and the color of the resin and whether the filler can meet the fineness requirements at high temperatures. Recent construction experience has confirmed that the heat resistance and cracking resistance of petroleum resins are slightly worse than those of resins. Hot melt marking should have UV resistance, such as using rutile titanium dioxide or using additives with UV resistance to improve marking materials, which is also a reasonable method to prevent discoloration of hot melt marking coatings.