Characteristics and Adhesion Principle of Painting Glass Beads

With economic activities become frequent day by day, there has been an increasing traffic congestion, resulting in a year-on-year increase in road traffic accidents, which becomes a social problem that needs to be settled urgently. A road traffic marker, placed on the road surface or other facilities, is a facility to control the traffic direction and disperse the flow of traffic through prescribed lines, arrows, text, façade markings, cornices, or other guiding devices. It conveys fixed base information about the road to vehicles and pedestrians, which is particularly important for drivers. Traffic signs are mainly laid on the surface of the road, which is exposed to the sun, rain, wind, snow and ice, and the impact of the vehicle, so there are strict requirements on its performance. Firstly, it requires short drying time and simple operation to reduce traffic interference; secondly, it requires strong reflective ability, bright color and strong reflective light for good visibility at day and night; thirdly, it has anti-slip and wear resistance to ensure traffic safety and service life.

After spreading the glass beads with a thermoplastic coating on the marker, it should have quick-drying properties in a short time (less than 5min) regardless of the climate. In general, glass beads for road marking paint have good, quick drying (hardening) properties. It hardens quickly in the cold season and slowly in the warm season. The coated film cures quickly and kinks due to shrinkage. The surface flow creates parallel gaps. Glass beads for road marking paint also have poor fixation quality. When the coating cures slowly, not only do the scattered glass beads sink into the coating and reduce reflective power, but they also slow down the traffic open time and reduce travel capacity. So, the temperature of the paint in the molten state is usually lowered to reduce the curing time.

There must be a strong adhesion between the marking film and the pavement, which is not easy to flake or break. It adheres well to the road surface and the coating, which does not flake off quickly due to vehicle crushing, skidding, and braking; it also won't crack, flex, or peel as the pavement swells and contracts from seasonal temperature changes. The thermoplastic road marking coating is heated to 180℃-220℃ with a hot-melt axe (choose the temperature according to the type of petroleum resin used in the coating and the formula), making the thermoplastic resin in the coating melt, and the coating becomes molten and flowing. Then it is coated on the road surface with a special marking machine. Meanwhile, spread the glass beads for road marking paint and cure it at room temperature. When applied on cement pavement, the high-temperature molten coating and the cement pavement are connected mechanically, so the adhesion is poor. Therefore, it is necessary to apply the undercoating agent for road marking to enhance the adhesion between the road surface and the coating in advance.