Thermoplastic road marking paint, also called hot melt marking paint, is a kind of powder paint. When applied as road surface markings, a hot melt kettle is used to heat it to to melt the powder, after which it is sprayed on the road surface. After cooling, the paint forms a thick polymer layer, which is wear-resistant, bright, and reflective. In recent years, practical applications tests have proved that the marking lines lack surface roughness and can easily cause wheel slip, resulting in a traffic crash in snow and rainy weather. Therefore, some countries once restricted the use of this paint or demand the use of anti-skid particles. In order to increase the antiskid performance of the line, thermoplastic paint has added reflective glass beads and other coarse fillers. Thermoplastic can be used very effectively for large anti-skid areas on roads and pedestrian walkways by adding glass beads. It can be produced in any colour and is suitable for car parks, factory walkways, and many other areas. It hardens quickly and can be driven over after just a few minutes.
Thermoplastic marking paint consists of synthetic (polymeric or non-polymeric) resin, glass beads, pigments, fillers (fine like calcium carbonate and coarse like sand), packing materials, additives, etc.
A road marking machine is a machine specially used to mark different traffic lines on road surface, and some can remark on old lines directly. It can screed, extrude, or spray processed road paint onto the road surface to form durable coating lines. A hot melt kettle is used for continuously heating, melting, and stirring thermoplastic marking paints, preparing molten paints for the thermoplastic machine, especially for long-distance road-line-marking work. The molten paint quality can affect the line quality greatly.
Marking materials often suffer a decline in retroreflectivity over time due to abrasion, contamination and embedment of wear products. Independent field studies show that elements such as well-graded glass beads and higher-solid-content paint can raise retroreflectivity by about 10 % and extend service life significantly. In some cases, mechanical or water-based cleaning of existing markingsâÂÂsuch as low-pressure or high-pressure water-blastingâÂÂhas been reported to improve visibility and refreshing of aged markings.
Thermoplastic paints, when used as road markings, are a source of microplastic pollution. Abrasive wear of road marking paint resins has been claimed to be responsible for 7% of all microplastic pollution, with estimates ranging from 0.7% to 19%.