Key points for road marking and hot melt coating construction

The hot melt road marking coating utilizes the thermoplastic properties of synthetic resin to provide quick drying properties. The hot melt properties of synthetic resin are utilized to firmly bond the marking with the road surface. 

Hot melt reflective road marking coatings are generally composed of thermoplastic resins, pigments and fillers, reflective materials, and other additives. Hot melt coatings have advantages such as good adhesion, long wear life, strong night reflection performance, fast drying during construction, good weather/water resistance, and low cost, low price, and green environmental protection.

The hot melt coating is powdery at room temperature. There are no solvent volatile components in the ingredients. Construction heating causes it to melt, and then specialized equipment is used to coat it on the ground, relying on physical condensation to solidify into a film. The thickness of the marking coating made of hot melt coating is (1.0-2.5) mm, and the coating is mixed with reflective glass beads. 

During the marking construction, reflective glass beads are sprinkled on the surface. This type of road marking has good nighttime reflective performance and a long service life. Based on the estimated demand for various road marking coatings in the construction of large highways with traffic flow, it can generally reach 2-3 years.

The hot melt marking coating is a solid powder at room temperature. During construction, the coating is placed in a melting kettle, with the temperature controlled between 180 ℃ and 210 ℃. The coating is mixed while melting, and when it is in a molten flow state, it is placed in the insulation melting hopper of the marking car. 

The melt coating is then introduced back into the marking hopper and insulated to maintain the material in a molten state. Before marking, there is a pre marking machine to mark the position, and the primer should be applied using the lower coating machine according to the application position indicated on the design drawing. 

After the coating agent is completely dry, the marking paint can be applied. When starting the marking process, the marking bucket should be placed on the road surface. Due to a certain gap between the marking bucket and the ground, when the marking vehicle moves forward, a neat marking line should be scraped by automatic flow. The glass bead spreader can automatically and evenly spread a layer of reflective glass beads on the markings.

Key points for hot melt coating pavement construction:

1. When the coating is dissolved, the temperature is limited to 180-220. After dissolution, it is slowly stirred and kept warm for 3-5 minutes before being discharged, which can fully utilize the function of the hot melt road marking coating.

2. It is recommended to construct under conditions with a temperature above 0 to ensure a clean and dry working surface (please increase the material temperature appropriately for high-temperature construction).

3. Leave room for primer treatment and wait until the primer is completely dry before applying the markings.

4. For the newly completed cement pavement, please try to postpone construction or stop the bottom oil treatment twice after three months, otherwise the markings may fall off easily.

5. When constructing on roads with high traffic volume, after applying primer, please place a warning cap to prevent the wheels from crushing, taking away primer, and leaving dust.

Assuming that the material temperature is below 180, petroleum resin cannot be fully stretched, which affects the fluidity of the coating. During construction, the markings may appear fuzzed, resulting in numbness or more residue on the outside of the markings, which affects the appearance of the markings; At the same time, too low a temperature can affect the extension of petroleum resin molecules, weakening the adhesion of markings to the road surface.

The reasons for slow drying of the hot melt coating after making the marking are as follows:

1. The standard specifies an ambient temperature of 23, and the drying time for hot-melt marking coatings is below 3 minutes at 23 degrees Celsius. When the ambient temperature is higher than this temperature, the drying time correspondingly increases.

2. The temperature of the road surface is high. After the marking is completed, due to the high temperature of the road surface, the temperature of the asphalt road surface in summer is above 60 degrees. After the temperature of the hot line indicator line drops to the same temperature as the sidewalk, it no longer cools down and the signs are no longer dry. This phenomenon usually occurs during the day (around 11:00 to 16:00), especially when the double yellow line in the middle of the road surface is very serious. Due to the long sunshine time in the middle of the road, the heat dissipation is very slow.

3. The density of the marking paint itself is a problem. Excessive use of leveling agents and other additives can improve leveling performance, reduce coating costs, and reduce the softening point of the marking paint. The hot melt marking paint gradually dries and becomes soft.