The Reflective Effect of Hot-Melt Road Marking Paint in Rainy Night Conditions

In the field of road traffic safety, the visibility of markings is crucial for ensuring driving safety, especially at night and in adverse weather conditions, and its importance is self-evident. Among them, the rainy night environment is one of the severe tests for the reflective performance of road markings. After rainwater covers the road surface, a layer of water film will form, which will seriously interfere with the light reflection path of ordinary markings, causing the driver’s line of sight to be blurred and difficult to identify the lane, thereby greatly increasing the risk of accidents. Therefore, improving the reflective effect of hot-melt coating markings in rainy night environments has become a key direction for industry technological breakthroughs and product upgrades. TOP ROAD Transportation Technology Co., Ltd., as a company that has been deeply involved in the field of road marking materials for many years, has always been committed to improving the performance of its hot melt coating products in complex environments through technological innovation.

1、 The Challenge and Principle of Reflecting on Rainy Nights
The reflection of traditional hot-melt reflective markings mainly relies on glass beads scattered on the surface. In a dry state, glass beads can efficiently reflect the light of the car lights back into the driver’s eyes. However, in rainy night environments, this mechanism faces a dual challenge:

Water film interference: Rainwater forms a continuous water film on the surface of the marking, changing the refractive index of light at the interface between glass beads and air. After entering the water film, the light undergoes refraction, and most of it cannot effectively return to the direction of the light source, resulting in the “disappearance” of the marking or a sharp decrease in brightness.
Mirror reflection: The smooth surface of the marking line combined with a water film is prone to mirror reflection, scattering the light of the car lamp in other directions, forming a dazzling spot that interferes with the driver’s line of sight.
Therefore, in order to achieve effective rain night reflection, the marking must be able to maintain or generate special anti reflection ability even when covered by rainwater.

Hot melt marking construction

2、 The technical path to improve the reflective performance on rainy nights
To address this challenge, the industry has mainly innovated in two aspects: material formulation and structural design. TOP ROAD Transportation Technology Co., Ltd. has comprehensively applied the following technological paths in the research and development of its hot melt coating products to enhance the reflective effect on rainy nights:

The application of high refractive index glass beads: This is one of the core technologies for improving the reflective performance on rainy nights. TOP ROAD uses specialized rain night reflective glass beads with higher refractive index. Even under rainwater infiltration, high refractive index glass beads can more effectively “capture” and “guide” light passing through the water film, reflecting it back towards the driver’s direction, thereby maintaining a considerable reflective brightness on damp surfaces.
Optimizing the glass bead spreading process and embedding state: In addition to the performance of the glass beads themselves, the spreading amount and embedding coating state are also crucial. TOP ROAD ensures a reasonable distribution density and appropriate embedding depth of glass beads on the marking surface through precise control of the production process. A portion of the glass beads are partially exposed on the surface of the coating, and can directly come into contact with air even under thin layers of rainwater to function; The other part is firmly embedded as a reflective reserve for subsequent wear and tear, jointly ensuring the continuous reflective ability of the markings throughout their lifecycle.
Special surface structure design: Some high-end hot melt coatings are adjusted through formula to form fine concave convex textures or structures after the marking line is cured. This structure helps to break the continuous water film on the surface of the marking line, forming discontinuous water droplets or thinning the water film, reducing the loss of light in the water film, and increasing the probability of light reflection. Some of TOP ROAD’s high anti slip and rain night enhanced hot melt products incorporate this design concept.
Ensure coating thickness and durability: Adequate coating thickness is the foundation for carrying sufficient glass beads and ensuring their long-term adhesion. TOP ROAD’s hot melt coating ensures a standard and uniform thickness after marking construction through a stable resin system and filler ratio, providing a solid “anchoring” foundation for glass beads to resist vehicle rolling and rainwater erosion, prevent premature detachment of glass beads, and maintain long-term reflective ability on rainy nights.
3、 The decisive impact of construction quality on the reflective effect on rainy nights
Even high-quality materials require standardized construction to achieve their design performance. For hot melt marking lines that pursue reflective effects on rainy nights, the control of the construction process is particularly crucial:

Strict temperature control: The construction temperature of hot melt coating directly affects its fluidity, settlement and embedding state of glass beads. The temperature is too low, the coating leveling is poor, and the glass beads cannot be effectively embedded; If the temperature is too high, it may cause resin aging, affecting adhesion and the fixation of glass beads. TOP ROAD’s technical service team will provide professional construction temperature guidance for different seasons and product models.
Accurate glass bead spreading: The timing, amount, and uniformity of spreading must be strictly controlled. Spread too early, the glass beads may be covered too deeply by the coating; If the spreading is too late or insufficient, the surface reflective beads will be insufficient. TOP ROAD not only provides high-quality glass bead products, but also has accumulated rich experience in construction parameters, which can assist construction teams in optimizing this key process.
Base treatment and drying construction: Before construction, it is necessary to ensure that the road surface is clean and dry. Any oil, dust, or moisture can affect the adhesion between the coating and the road surface, and may form bubbles under the action of water vapor, damaging the integrity of the marking and indirectly affecting the uniformity of reflection. This is also a fundamental requirement repeatedly emphasized by TOP ROAD in various construction guidelines.
Hot melt marking construction

4、 Performance verification and standard compliance
The performance of reflective markings on rainy nights is not subjective, but is regulated by clear national standards such as GB/T 16311. This standard sets specific requirements for the reflectance brightness coefficient of Type II reflective markings (i.e. rain night reflective markings) under dry, humid, and continuous rainfall conditions. This means that a qualified rain night reflective hot melt coating must be able to demonstrate through laboratory simulations and on-site testing that it can maintain a low level of reflective performance under continuous rain conditions.

TOP ROAD Transportation Technology Co., Ltd.’s product research and quality control system strictly benchmarks and is committed to exceeding national standards. The company continuously verifies and optimizes the reflective data of its hot melt coating products under simulated rainy night conditions through laboratory simulation testing and actual road application tracking, ensuring the reliable performance of the products in practical applications. Choosing TOP ROAD’s hot melt coating means choosing a rigorously validated traffic safety solution that can withstand the challenges of rainy nights.

The reflective effect of road markings in rainy night environments is an important indicator for measuring the safety level of modern transportation facilities. It not only relies on a single high-quality material, but also is a systematic engineering that covers high-performance glass beads, scientific coating formulas, precision construction processes, and strict quality standards.

TOP ROAD Transportation Technology Co., Ltd., with a profound understanding of road safety requirements and continuous technological investment, has developed a series of hot-melt marking paint products that are a product of this systematic thinking. The company not only provides core materials with excellent rain night reflective potential, but also extends this performance guarantee to the entire process of pre-sales consultation, construction guidance, and post maintenance services. On the path of pursuing “safe and far-reaching”, TOP ROAD is committed to providing clearer and more lasting light on rainy nights to protect every road user.

Our company is a professional manufacturer of road hot-melt coatings, road retroreflective measuring instruments, and road marking machines. If you are interested, please feel free to communicate with me via email at any time export@toproadtraffic.com