High-intensity LED UV curing and surface marking system.

Abstract

The invention relates to a surface marking system (1) for the application and UV curing of a surface marking, the system (1) comprising at least one paint applicator (6), at least one LED UV lamp array (4), an on-board rechargeable power pack (3) and an air-cooling assembly, wherein the system (1) is operable to cure in a single pass, in ambient air and without the use of glass beads or other optically-transmissive fillers, a UV-curable coating having a dry-film thickness of up to 500 µm at a travel speed of at least 1 km / h. The invention further relates to a method of marking a surface with a surface marking system (1) of the invention.

Description

[0001] High-intensity LED UV curing and surface marking system.

[0002] The present invention relates to a mobile high-intensity LED UV curing and surface marking system specifically designed for the application and curing of high-performance coatings in road / surface marking, for outdoor environments, and in off-highway or non-public road markings, for indoor and private environments.

[0003] Road markings and lines are applied in outdoor environments, such as for example on public roads, city centres, public parking’s. Typical surfaces where the markings are applied to are asphalt, concrete, pavement tiling. Indoor line markings are applied in indoor environments, such as warehouses, logistic centers and private company areas. Typical surfaces where the line markings are applied include concrete, pavement tiling and industrial flooring.

[0004] Indoor application

[0005] Some indoor UV line marking applications still rely on manual rolling techniques, leading to inconsistent coverage and resulting in a high rate of application failures due to inadequate curing. These methods do not leverage the full potential of UV curing technology and often result in subpar performance, affecting durability, adhesion, and overall effectiveness under demanding conditions.

[0006] Contrary to road markings, line markings in indoor environments such as warehouses, need to have markings that are both strong and applied in thin layers. Due to the impact and abrasion from e.g. forklift wheels and heavy machinery, excessively thick line markings (those thicker than approximately 300 micrometers) are not preferable. Thick coatings can become more susceptible to damage. The challenge, therefore, lies in achieving a strong, thin, yet wear-resistant layer that can withstand the demanding conditions of indoor industrial settings.

[0007] Current UV indoor line marking systems present several problems. They typically require manual application methods such as rolling or brushing. This manual application is not only labor-intensive but also results in inconsistent layer thicknesses. Operators find it difficult to control the coating thickness accurately when applying by hand, especially when aiming for thin layers with minimal margin for error. This inconsistency often leads to curing failures due to uneven application and insufficient UV penetration, compromising the durability and adhesion of the markings.

[0008] Moreover, known UV curing systems for indoor markings are limited in the thickness of the resin paint layer that can be effectively cured, generally up to about 100 micrometers per layer or coat. Achieving uniform thin layers within this limited thickness range is challenging with manual application methods. The inability to consistently control layer thickness increases the risk of under-cured areas, leading to subpar performance and reduced wear resistance.

[0009] Current systems often rely on curing units with either conventional UV light sources or LED UV light sources, each with notable limitations. Conventional UV light sources, such as medium-pressure mercury vapor light sources and gallium-doped light sources, emit light over a broader spectrum which may support thicker layer curing; however, these light sources require frequent cooling intervals, slowing down the overall curing process. They are also more sensitive to shocks and vibrations, leading to increased maintenance and susceptibility to damage during transport. Additionally, conventional UV light sources have higher energy demands and require regular bulb replacements, making them less suitable for efficient, fully mobile indoor applications. Alternatively, LED UV systems used in some indoor applications allow for more consistent curing but require significantly slower movement speeds due their lower intensity or small surface dwelling over the paint. Having lower intensity LED UV light sources or a smaller surface dwelling over the paint to ensure adequate curing of the coatings, limits the efficiency of this application.

[0010] Furthermore, both conventional UV and LED UV curing systems currently used typically rely on being plugged into an electric outlet, restricting operators' mobility and range due to the electric cord, which hinders practical use in larger indoor spaces. These limitations highlight the need for an advanced solution to address the challenges of durability, mobility, and efficiency in indoor UV line marking.

[0011] Currently, there are systems capable of curing coating layers exceeding 100- 200 microns in thickness; however, they achieve this by incorporating glass beads, which are either partially or fully embedded within the coating layer. These glass beads facilitate curing by creating an excimer-like effect that helps extend UV penetration depth, allowing for full curing of thicker layers that would otherwise be challenging to achieve. This reliance on glass beads to reach sufficient curing depth limits the flexibility of these systems, particularly in contexts where beads are impractical or undesired.

[0012] While glass beads are essential in outdoor road marking applications — primarily for retroreflectivity on highways to improve night-time visibility — these beads are typically unnecessary and rarely used in off-highway or indoor settings. Indoor environments, such as warehouses, logistic centers, and private parking facilities, do not require the reflective properties provided by glass beads, which are primarily needed to ensure safety for nighttime vehicle navigation. Consequently, for these indoor applications, systems that rely on glass beads for effective curing may present added costs, logistical complexity, and reduced functionality without delivering relevant benefits. A challenge in known systems arises from the difficulty of curing coatings that contain higher levels of pigmentation, as these pigments, such as titanium dioxide (TiO2), are essential to achieve the necessary opacity and visual contrast in indoor settings. In applications where thin layers are preferred, such as warehouses or private parking areas, coatings must have sufficient pigmentation to provide clear, high-contrast line markings that are easily visible to operators and pedestrians. However, the presence of these pigments creates a technical obstacle, as they absorb and scatter UV light, which complicates the curing process, particularly in pigmented coatings where a full cure is essential for durability.

[0013] Higher concentrations of pigments, such as TiO2at 5-20 weight percent, contribute to optimal opacity and brightness in the marking system but pose challenges for UV penetration. Titanium dioxide, often used as a white pigment, strongly absorbs UV light below approximately 380 nm, which restricts the depth to which UV light can penetrate, potentially leaving the coating incompletely cured. This effect is compounded by other pigments, like yellow, which also fully absorb UV light within the standard LED UV curing wavelengths, further preventing light from reaching lower layers. Consequently, systems designed for these applications require stronger UV light sources to ensure sufficient light penetration, allowing for a complete cure despite the higher pigment load. This balance is critical to achieve the visual contrast and durability necessary for effective indoor line marking applications.

[0014] Outdoor application

[0015] UV curing technology has traditionally been confined to highly controlled environments, such as industrial settings, where the application conditions can be tightly managed. However, extending UV curing technology to outdoor applications, particularly in the field of line marking, presents significant challenges related to i.a. a mobile application in an uncontrolled environment.

[0016] For indoor applications minimizing downtime is of great importance.

[0017] Conventional UV light sources, such as medium-pressure mercury vapor light sources and gallium-doped light sources, emit light over a broader spectrum of wavelengths, which can enhance curing performance and allow for curing thicker layers, specifically required for outdoor applications. However, aside from some of the light sources emitting ozone, these light sources are very sensitive to harsher conditions encountered on the road; that is, they are prone to damage from mechanical shock and vibration during transport, leading to frequent light source failures and increased maintenance requirements. Additionally, they demand more energy and require regular bulb replacements, making them less suitable for full mobile applications.

[0018] In known traditional road marking systems, micro beads such as glass beads are added to the paint to achieve retroreflectivity, enhancing night-time visibility by reflecting light back to its source. However, a further problem with known UV road marking systems is that they rely on glass beads (or reflectors) to achieve sufficient curing depth when applying thicker layers of UV-curable paint. Without the inclusion of glass beads, the maximum achievable layer thickness of cured paint in available systems would be significantly reduced.

[0019] Glass beads are primarily needed for retroreflectivity in outdoor road markings, such as highways, to ensure source, like minimum reflective properties for safety reasons. By reflecting light back towards the car's headlights, glass beads enhance the visibility of road markings during night-time driving conditions. In contrast, the present invention decouples retroreflectivity from curing: glass beads may be included to satisfy road-safety retroreflectivity requirements, but are not required for curing performance. The system achieves one-pass curing of 300-500 pm layers without optically-transmissive components, under ambient air. Where beads are used, they are retained solely for retroreflectivity.

[0020] Glass beads can be incorporated into road marking systems either by premixing into the material — common in many thermoplastic applications — or by postspraying onto the surface immediately after application, as is typical in standard paint-based surface markings.

[0021] Another problem in known systems is related to the high concentration of pigments, such as titanium dioxide (TiO2), commonly used in known UV systems at about 5 to 13 weight percent. To achieve optimum opacity and brightness, the marking system needs a sufficiently high amount of pigments.

[0022] This presents a challenge for UV curing systems with high layer thicknesses because it is well known that pigments — including TiO2 used as a white pigment — absorb and scatter UV light, preventing thicker layers from being fully cured (both at the surface and in depth). The higher the concentration of pigments, the better the opacity and visual appearance, but the more difficult it becomes to cure thicker layers of UV paint with UV light. Titanium dioxide, for example, is a very opaque material and strongly absorbs UV light below approximately 380 nm.

[0023] Different pigments absorb UV light at various wavelengths, making it harder for the light to penetrate and fully cure the coating. For instance, yellow pigments completely absorb UV light in available LED UV curing wavelength ranges. Along with the fact that road marking paints are preferably applied at high film thicknesses, this situation is exactly the opposite of the ideal for UV curing, where low film thicknesses and clear or lightly pigmented paints are preferred.

[0024] The application of UV coatings in road marking, particularly for outdoor use, presents significant challenges due to the need for durability and visibility. While thicker coatings can enhance durability by better withstanding environmental factors and heavy traffic, local regulations may require specific coating thicknesses to meet safety standards. Traditionally, achieving both high durability and visibility in UV-cured coatings — whether thin or thick — has been difficult due to curing limitations with highly pigmented layers.

[0025] Curing efficiency in UV curing processes is a significant challenge, particularly for thicker or more opaque materials. It is highly dependent on the peak irradiance — the maximum UV light intensity at the material's surface. High peak irradiance enhances curing efficiency by providing sufficient energy to penetrate deeper into the coating, ensuring a full cure throughout the entire thickness (through-cure), which results in improved adhesion and durability. While dwell time (the duration of exposure) plays a role, curing efficiency is not solely dependent on it. Factors such as irradiance intensity, spectral distribution and the material's absorption characteristics also critically influence the curing process. By utilizing high peak irradiance, the system can achieve effective curing more efficiently, potentially reducing the required dwell time and optimizing the total energy used for curing.

[0026] Avoiding incomplete curing is a significant challenge. In thicker coatings, deeper layers may remain uncured if the UV light does not provide sufficient irradiance. This can lead to poor adhesion, surface tackiness, and compromised durability of the cured material (e.g., failed application).

[0027] Known systems as disclosed in US10822755B1 (Strouds), W02021020975A1 (Damar) and , EP0915136A1 (Showa Denko) or WO2008141743A1 (Hexion) present one or other of the above limitations.

[0028] The road and surface marking industry, encompassing indoor settings like warehouses and outdoor environments such as highways, requires a robust solution capable of high-intensity UV curing under varied and often harsh conditions while ensuring operator safety and compliance with high safety standards. This invention addresses these needs.

[0029] The purpose of the present invention is to provide a solution to one or more of the aforementioned and other disadvantages.

[0030] To this end the invention concerns a surface marking system for the application and UV curing of a surface marking, the system comprising a paint applicator, a LED UV lamp array and a power supply, whereby the system is movable over a road or surface, and the system is configured such that as it moves, the paint applicator applies a coating layer of UV paint on a road or surface, and the LED UV lamp array cures the coating layer, characterised in that the system comprises: a. at least one paint applicator arranged to dispense a UV-curable coating on a surface, b. at least one LED UV lamp array arranged downstream of a paint applicator and configured to: i) emit radiation having a peak wavelength in the range 365-495 nm, preferably 365-405 nm; ii) provide a peak irradiance of at least 2500 mW / cm2at the coating surface, and iii) deliver an energy dose of at least 2500 mJ / cm2in a single pass; c. an air-cooling assembly configured to maintain an LED-junction temperature of at most 100 °C, preferably 90 °C, during continuous operation at the irradiance specified in feature (b); d. an on-board rechargeable power pack, comprising one or more battery modules, capable of supplying at least 3600 W continuous electrical power and at least 18 kW peak electrical power; wherein the system is operable to cure in a single pass, in ambient air and without the use of glass beads or other optically-transmissive fillers, a UV-curable coating having a dry-film thickness up to 500 pm at a travel speed of at least 1 km / h.

[0031] In one embodiment the system is operable to cure a UV-curable coating having a dry-film thickness of up to 400 pm and a concentration of pigment of 2-10 wt %, preferably 2-8 wt %.

[0032] In another embodiment the system is operable to cure UV-curable coating having a dry-film thickness of up to 500 pm and a concentration of pigment of 0.1 -4 wt %, preferably 0.1 -2 wt %.

[0033] In a specific embodiment the system is operable to cure a UV-curable coating having a dry-film thickness of up to 400 pm and a concentration of titanium dioxide pigment not exceeding 2.5 wt %.

[0034] In another specific embodiment the system is operable to cure a UV-curable coating having a dry-film thickness of up to 500 pm and a concentration of titanium dioxide pigment not exceeding 1 wt %.

[0035] In a specific embodiment the system is operable to cure a UV-curable coating having a dry-film thickness of up to 300 pm and a concentration of pigment of 3- 10 wt %, and a dry-film thickness of up to 500 pm and a concentration of pigment of 0-3 wt %.

[0036] In one embodiment the system is self-propelled and comprises a traction drive powered by the power pack.

[0037] In one embodiment of a system the power pack provides at least 4 kW continuous electrical power.

[0038] In a preferred embodiment the pigment is titanium-dioxide. In one embodiment the irradiance is applied at a distance of approximately 3 to 5 cm from the surface.

[0039] In one embodiment the energy dose used for indoor environments is preferably 2500-3500 mJ / cm2. In another embodiment the energy dose used for outdoor environments is preferably 2500-4500 mJ / cm2.

[0040] Known systems as disclosed in Damar (W02021020975A1 ) and Strouds (US10822755B1 ) achieve UV curing of coatings by incorporating glass beads into the paint as light guides; Res Derivatives (US 5,294,798) describes only alternator-driven solvent-based striping rigs; and Komatsu (JP H04-350204) uses a scanning laser in a nitrogen atmosphere.

[0041] Conventional UV road-marking solutions, such as WO 2021 / 020975 (Damar), US 5,294,798 (Res Derivatives), and JP H04-350204 (Komatsu), rely on either mercury lamps, nitrogen inerting, or embedded glass beads to achieve effective curing depth. These systems are bulky, environmentally constrained, or unsuitable for field deployment.

[0042] Mobile surface marking units typically face limitations concerning energy supply. The challenge is to find a balance between light source intensity (irradiance in mW / cm2), exposure time (dwell time), and coating thickness, all while managing a limited energy draw.

[0043] Existing UV surface curing systems are limited by weaker or smaller UV light sources, typically constrained to coatings of about < 250 pm thickness at 5-13 wt% TiO2, and application speeds of only 1 .5-2 km / h. (State of the art)

[0044] In a specific embodiment the present invention enables one-pass curing of indoor bead-free coatings containing < 2.5 wt% TiO2, at < 400 pm thickness, in ambient air, and outdoor bead-inclusive coatings containing 3-8 wt% TiO2, at 500 pm thickness, with beads included solely for retroreflectivity. Application speeds of up to 5 km / h are achievable while maintaining curing depth, opacity, and adhesion. These bead-free embodiments limit TiO2 to < 2.5 wt%, ensuring opacity with curability, while bead-inclusive embodiments permit higher TiO2 contents e.g., 3-8 wt%, for visibility, with beads used solely for retroreflectivity. The high-intensity LED flood array provides sufficient irradiance and dose to through-cure these layers in ambient air.

[0045] In a specific embodiment, typically for indoor environments and low-pigmented outdoor environments, the system is a self-propelled surface-marking system comprising: a) a paint applicator arranged to dispense a UV-curable coating on a surface; b) a LED ultraviolet lamp array arranged downstream of the applicator and configured to i) emit radiation having a peak wavelength in the range 365-405 nm, ii) provide a peak irradiance of at least 2 500 mW per square centimetre at the coating surface, and iii) deliver an energy dose of at least 2 500 mJ per square centimetre in a single pass; c) an air-cooling assembly that maintains an LED-junction temperature not exceeding 90°C during continuous operation at the irradiance specified in feature (b); d) an on-board rechargeable battery pack capable of supplying at least 3 600 W continuous electrical power and at least 18 kW peak electrical power to the system; and e) a traction drive powered by the battery pack, wherein the system is operable to cure, in one pass and without the use of glass beads or other optically-transmissive fillers, a UV-curable white coating having:

[0046] - a dry-film thickness of up to 400 pm, and

[0047] - a titanium-dioxide pigment content not exceeding 2.5 wt %, at a travel speed of at least 1 km h1.

[0048] The system of the invention distinguishes from known systems by one or more of the following features and advantages. Flood LED lamp array as opposed to UV scanning lamps. High-intensity LED flood curing: > 2500 mW / cm2irradiance and > 2500 mJ / cm2dose for one-pass curing of bead-free coatings up to 500 pm thickness with limited pigment / titanium dioxide content. Beads are not required for curing. Coating thickness is typically 500 pm for outdoor environments and 400 pm for indoor environments. Optional drop-on beads only for reflectivity purposes. No nitrogen inerting: curing occurs in ambient air using a stationary flood array, simplifying industrial floor or warehouse marking. Quantified thermal management: engineered airflow, ducting, and IMS / TIM interfaces maintain LED junction below 100 °C, preferably < 90 °C, a feature not taught in prior art. True battery-powered mobility: > 3.6 kW continuous battery power supply supports sustained indoor operation without alternators or external power. Multi-layer flexibility: supports primer / base / topcoat application with controlled gel-cure and full cure sequences, improving durability and workflow efficiency. Multi-layered single pass coating supports thicker tension- free coatings compared to one layer of the same thickness.

[0049] UV coatings require a high-intensity UV light to cure rapidly and fully, particularly for pigmented coatings applied in thicker layers. The invention addresses these challenges by incorporating high-intensity UV light sources into a mobile unit capable of curing UV coatings up to 500 pm thick, combined with low pigmented systems. For low pigmented systems (e.g. 0-2% by weight titanium dioxide), the system enables the curing of coatings up to 500 pm thick in a single pass. For higher pigmented systems (e.g. 2-10% by weight titanium dioxide), the invention effectively cures coatings at thicknesses that comply with local regulations and meet durability and visibility requirements, and this without requiring optically transmissive components or glass beads for the purpose of fully curing the layer. Contrary to known systems where the use of glass beads or other reflectors fully embedded in the paint only has a purpose for better curing, the system of the invention does not require glass beads or other reflectors for effective curing. The optional glass beads or other reflectors on the surface of a coating merely have the effect of better retroreflectivity for standard regulations on road safety.

[0050] This battery-driven configuration enables fully mobile operation within indoor and off-highway environments without reliance on external power sources, providing operators with a cord-free, maneuverable solution adaptable to a variety of surface types and applications.

[0051] In thicker coatings, such as for outdoor applications and road-marking, deeper layers may remain uncured if the UV light does not provide sufficient irradiance.

[0052] In a specific embodiment of a surface marking system as previously set out the least one LED UV lamp array provides a peak irradiance of at least 3500 mW / cm2at the coating surface, and delivers an energy dose of at least 5000 mJ / cm2in a single pass; and the on-board power pack is a hybrid power pack comprising one or more rechargeable battery modules and optionally an auxiliary generator, wherein the power pack is capable of supplying at least 6000 W, preferably at least 4000 W, continuous electrical power and at least 20 kW, preferably at least 18 kW, peak electrical power; wherein the system is operable to cure in ambient air, in a single pass and without the use of glass beads or other optically-transmissive fillers for effective curing, a UV-curable coating having a dry-film thickness up to 500 pm, at a travel speed of at least 2 km / h.

[0053] In a specific embodiment the system is operable to cure UV-curable coating having a concentration of pigment not exceeding 3-8 wt %. As such, in a specific embodiment typically for high-pigmented outdoor environments, the invention concerns a surface marking system for the application and UV curing of a surface marking, the system comprising a paint applicator, an LED UV lamp array and a power supply, whereby the system is movable over a road or surface, and the system is configured such that as it moves, the paint applicator applies a coating layer of UV paint on a road or surface, and the LED UV lamp array cures the coating layer, characterised in that the system comprises: a. at least one paint applicator arranged to dispense a UV-curable coating on a surface, b. at least one LED UV lamp array arranged downstream of a paint applicator and configured to: i) emit radiation having a peak wavelength in the range 365-495 nm, preferably 365-405 nm; ii) provide a peak irradiance of at least 3500 mW / cm2at the coating surface, and iii) deliver an energy dose of at least 5000 mJ / cm2in a single pass; c. an air-cooling assembly that maintains an LED-junction temperature not exceeding 90 °C during continuous operation at the irradiance specified in feature (b); d. an on-board hybrid power pack comprising one or more rechargeable battery modules and optionally an auxiliary generator, the hybrid power pack capable of supplying at least 6000 W, preferably at least 4000 W, continuous electrical power and at least 20 kW, preferably at least 18 kW, peak electrical power; wherein the system is operable to cure in a single pass, in ambient air and without the use of glass beads or other optically-transmissive fillers, a UV-curable coating having a dry-film thickness up to 500 pm, and a pigment content not exceeding 3-8 wt %, at a travel speed of at least 2 km / h. In one embodiment the system comprises an optional drop-on dispenser positioned adjacent the paint applicator for dropping glass beads or other retro- reflective particles onto the surface of a freshly applied coating layer before UV curing.

[0054] In one embodiment of a system of the invention a controller synchronizes the dispenser with a switch-on of the LED UV lamp array so that the glass beads or other retro-reflective particles are at least partly embedded in the coating before curing.

[0055] In one embodiment of a system of the invention a controller synchronises the bead dispenser with the switch-on of the LED lamp array so that the beads are at least partly embedded before the coating surface receives more than 500 mJ / cm2.

[0056] In one embodiment the system is a ride-on or truck-mounted road marking system comprising a traction drive powered by the hybrid power pack.

[0057] In one embodiment of a system of the invention the hybrid power pack supplies at least 8 kW continuous electrical power.

[0058] In one embodiment of a system of the invention the auxiliary generator recharges the battery modules during transit between marking sites.

[0059] In one embodiment of a system of the invention the on-board power pack is exchangeable and connectable to an external charger or auxiliary generator.

[0060] In one embodiment of a surface marking system of the invention, the LED UV light source comprises a UV floodlight with an intensity of 2000-6000mW / cm2, preferably 2500-4000mW / cm2, and a more focused UV light source with a high- intensity of 5000-16000mW / cm2, preferably 5000-8000mW / cm2. In one embodiment of the invention the power supply unit is a full battery system comprising one or more rechargeable power stations. In another embodiment the power supply unit (3) comprises a hybrid system comprising one or more rechargeable power stations in combination with an engine-driven alternator, with an optional recharging of the power stations by the alternator during use of the system.

[0061] In a specific embodiment, typically for outdoor environments, the system is a ride-on or truck-mounted road-marking system comprising: a) a paint applicator arranged to dispense a UV-curable marking composition on a road surface; b) a dispenser positioned adjacent the paint applicator for dropping glass beads or other retro-reflective particles on to the fresh composition; c) a LED ultraviolet lamp array arranged downstream of the applicator and configured to i) emit radiation having a peak wavelength in the range 365-405 nm, ii) provide a peak irradiance of at least 3 500 mW cm-2, and iii) deliver an energy dose of at least 5 000 mJ cm-2 in a single pass; d) a cooling assembly, air- or liquid-based, that maintains a LED-junction temperature not exceeding 90 °C during continuous operation at the irradiance specified in feature (c); e) a traction drive and a hybrid power pack comprising one or more rechargeable battery modules and optionally an auxiliary generator, the power pack supplying at least 6 kW continuous electrical power and at least 18 kW peak electrical power to the system; wherein the system cures, in one pass, a UV-curable road-marking coating having a dry-film thickness up to 500 pm and a pigment content of 3 wt % to 8 wt % TiO2, the coating optionally containing partially-embedded glass beads, and the system travels at a speed of at least 2 km / h during application. The present invention delivers several technical advantages over known UV curing and road-marking systems by introducing a fully mobile LED flood-array curing platform. Delivers higher irradiance and dose: at least 3500 mW / cm2peak irradiance and > 5000 mJ / cm2dose, enabling one-pass curing of up to 500 pm outdoor coatings. Removes dependency on glass beads for curing: bead- free curing up to 400 pm with TiO22.5 wt%; beads are retained only for roadsafety retroreflectivity. Bead-limited thick-layer curing: layers of up to 500 pm cured in one pass, with beads included solely for retroreflectivity; Introduces quantified cooling management: an air-cooling assembly (or optional liquid loop) maintains LED junction below 100 °C, preferably < 90 °C during continuous high-power operation. Uses a scalable high-power battery / hybrid power supply - providing > 6 kW continuous and > 18 kW peak, enabling sustained field curing, scalable batteries, or alternator recharging. Operates in ambient air, not inert gas - curing occurs outdoors under ambient conditions, eliminating nitrogen shielding. Enables wet-surface curing: enables curing on damp or slightly wet road surfaces, reducing lane-closure time. Industrial-grade LED floodlamp array: multi-zone (365-405 nm) high-irradiance design (>2,500 mW / cm2, >3,000 mJ / cm2dose).

[0062] The invention introduces a differentiation between coatings with varying purposes, such as indoor and outdoor usage, and varying pigment levels. Current UV road marking coatings containing more than 5% by weight titanium dioxide (TiO2) provide the necessary opacity and retroreflectivity required for safety and visibility. Although these coatings are more challenging to cure due to their high pigment concentration obstructing UV penetration, the system's high-intensity light sources efficiently overcome this obstacle, enabling effective curing regardless of the coating thickness. This allows for compliance with safety standards while optimizing curing efficiency. In contrast to known systems using 5-20 wt % TiO2,

[0063] Furthermore, the invention enables the use of specially formulated low- pigmented UV line marking paints containing between 0 and 2% by weight titanium dioxide (TiO2) for white coatings. These low-pigment formulations offer dual benefits: they reduce environmental impact by decreasing TiO2content, thereby lowering the carbon footprint, and they leverage the inherent advantages of UV curing technology, such as minimal to zero volatile organic compound (VOC) emissions. The system is capable of curing these low- pigmented coatings at thicknesses up to 500 pm and application speeds of up to 5 km / h, representing a significant advancement in UV curing technology.

[0064] This system provides a robust, efficient, and environmentally friendly solution for modern road marking, capable of meeting stringent durability and visibility requirements even under challenging uncontrolled outdoor conditions.

[0065] Higher-intensity UV flood light sources on a mobile platform, particularly those operating at levels above 2000 mW / cm2, require substantial energy to function effectively. Despite advancements in LED UV technology, these high-intensity light sources still demand significant power supplies. Traditional mobile systems are typically constrained by their energy sources, such as standard engines on mobile units or battery-driven units, which are insufficient to support the operation of powerful LED UV light sources. The invention addresses these limitations by incorporating an innovative energy battery supply system, enabling even smaller mobile units to reliably power LED UV flood curing light sources at intensities exceeding 2000 mW / cm2. This capability allows for the integration of higher-intensity UV light sources into various configurations, optimizing the curing process for different applications.

[0066] The terms LED UV lamp array and LED UV light source are used interchangeably throughout the text.

[0067] The integrated LED UV light sources are designed to achieve optimal curing of thick and pigmented coatings for visible line marking applications requiring high opacity. This system incorporates both high energy (measured in J / cm2) and high-intensity (measured in W / cm2) in the curing process, particularly when applying thicker coatings.

[0068] Energy and intensity are two interrelated factors that work together to achieve thorough curing, ensuring that the entire coating, especially thicker layers, receives sufficient exposure to initiate and complete the curing process. Energy, or UV dosage, represents the total accumulated photon quantity that reaches the surface and is directly related to the dwell time under the LED UV light source.

[0069] For UV coating applications, where pigmented coatings can easily exceed 100 pm in thickness, intensity becomes a paramount factor. High intensity, defined as the radiant power arriving at a surface per unit area, ensures that sufficient energy penetrates through the top layers of the coating to reach the deeper layers. This is particularly important because, as UV light penetrates a coating, its power diminishes due to absorption and scattering. According to the Beer-Lambert law, higher surface intensity leads to greater energy availability at deeper layers, making it possible to cure thick films effectively.

[0070] Moreover, higher intensity not only accelerates the polymerization process but also improves the durability of the system by completing a full cure. High- intensity curing with the right wavelengths helps to overcome issues such as surface tackiness, deep cure failures and oxygen inhibition, which are common challenges in UV curing. By rapidly initiating the curing process, high intensity mitigates these issues and ensures a more uniform and durable cure throughout the coating.

[0071] Flood light source

[0072] To effectively cure material layers exceeding 400 pm in thickness, the invention provides various UV light source configurations designed to deliver both extended dwell time and high irradiance. The extended dwell time — the duration during which the LED UV light source remains over the coating — ensures sufficient exposure for thorough curing. Simultaneously, the high irradiance facilitates deeper penetration of UV energy into the coating, overcoming absorption losses and enabling complete curing of thick layers.

[0073] In one embodiment of a surface marking system of the invention the LED UV light source is a high-intensity flood LED UV light source with a uniform irradiance.

[0074] The configuration features a LED UV curing light source with an optimized surface area designed to maximize dwell time and ensure thorough curing, particularly when treating larger surfaces. Unlike smaller high-intensity LED UV light sources, these flood light sources are engineered to deliver consistent irradiance across the entire coverage area, ensuring uniform curing without compromising on application speed or quality.

[0075] The size and width of these flood light sources are customizable to match the specific requirements of different mobile units in a surface marking system of the invention. This flexibility allows for the optimization of curing performance based on the energy capacity available on the unit in relationship to the output of the paint on the unit.

[0076] Typically, for indoor applications, these light sources are designed to be around 150mm wide and up to 250mm long, providing sufficient energy for indoor environments and applications needs. For outdoor use, where larger surface areas, faster application speeds and thicker coating thicknesses are required for greater durability, the LED UV light sources can be designed with widths ranging from 150 mm to 550mm. Outdoor light sources may typically have lengths from 300 mm up to 1000 mm, depending on the size of the mobile unit to accommodate the broader, more demanding applications typical in road marking.

[0077] The flood LED UV light source operates with a uniform irradiance typically ranging from 2000 mW / cm2to 6000 mW / cm2making the light source highly effective for consistent curing across large surfaces. The consistent output ensures that the curing process is not only reliable but also optimized for speed, allowing for faster processing times without sacrificing the quality of the cure.

[0078] In a specific embodiment the LED UV light source is configured to emit a uniform irradiance ranging from 2000 mW / cm2to 4000 mW / cm2in air-cooled configurations, preferably ranging from 2500 mW / cm2to 3500 mW / cm2.

[0079] LED UV lamp zoning

[0080] The LED UV curing light sources integrated into this invention are designed in various configurations, each tailored to meet the specific demands of different applications. Depending on the intended use — whether for indoor environments like warehouses or off-highway road markings like airports or private parkings, or outdoor road marking on highways or urban environments — these light sources are designed to address the unique requirements associated with each scenario.

[0081] For instance, indoor applications may prioritize precise, controlled curing over smaller areas, often requiring thinner coatings and lower curing speeds. In contrast, outdoor applications typically require faster application, with thicker coatings and higher-speed processes, demanding more robust and powerful light source configurations.

[0082] The invention offers a range of LED UV light source configurations with varying intensities and widths, enabling optimal curing performance across all types of applications. The system can be adjusted to match the specific curing requirements of the application.

[0083] By incorporating these versatile light source options, the invention ensures that the curing process is consistently effective, regardless of the application’s thickness speed, or changing environmental conditions we experience for this type of UV application. This adaptability allows for the most efficient use of energy and resources while delivering more consistent application and curing results in both indoor and outdoor UV curing applications.

[0084] In one embodiment, typically for indoor environments and low-pigmented outdoor environments as disclosed above, the LED UV lamp array comprises a first section that emits radiation having a peak wavelength of 405 nm at an irradiance of 5000-8000 mW / cm, and a second section, located downstream of the first section, that emits radiation having a peak wavelength of 365 nm at an irradiance of 2500-4000 mW / cm. The LED UV lamp array may be divided into transverse modules that are independently switchable in increments of not more than 25 mm to match a selected line width.

[0085] In another embodiment, typically for high-pigmented outdoor environments as disclosed above, the LED UV lamp array comprises a first section that emits radiation having a peak wavelength of 405 nm at an irradiance of 8000-10000 mW / cm, preferably 6000-10000 mW / cm, and a second section, located downstream of the first section, that emits radiation having a peak wavelength of 365 nm at an irradiance of 3500-5000 mW / cm. The LED UV lamp array may be divided into transverse modules that are independently switchable in 50 mm increments to match a selected line width.

[0086] The LED UV lamp array modules are dimmable over a range of 0-100 % of maximum output. The system of the invention provides a LED UV light source comprising multiple (energy saving) UV sections having a different irradiance and / or wavelength. The UV sections are typically configured widthwise, whereby a specific section covers the full width of the light source, but only part of the length. The sum of the length of the sections corresponds to the length of the LED UV light source unit.

[0087] In one embodiment the sections comprise a different irradiance and an identical wavelength. In another embodiment the sections comprise a different wavelength and an identical irradiance. Yet in another embodiment the sections comprise a different wavelength and a different irradiance.

[0088] In a specific embodiment of a surface marking system of the invention a LED UV light source is provided comprising multiple sections, with a higher intensity section typically configured near the front of the light source, and a lower intensity section near the back of the light source. As such the higher intensity UV section cures the coating first, followed by the lower intensity UV section.

[0089] In one embodiment the LED UV lamp array comprises a UV floodlamp with an intensity of 2000-6000mW / cm2, preferably 2500-4000mW / cm2, and a more focused UV lamp array with a high-intensity of 5000-16000mW / cm2.

[0090] Hereby the system uses a LED UV configuration that builds upon the traditional flood lights described previously, introducing an additional feature to address specific curing challenges associated with thicker or more heavily pigmented coatings. The enhanced flood lights maintain the same foundational design, providing uniform coverage across the application area. However, they incorporate a specialized higher-intensity section, typically located at the beginning of the lighted area, that is the section of the light source that hits the line marking first. The flood LED UV light source comprises one irradiance surface (flood light), but in a combination that provides different intensity. The combination e.g., can be a flood light source with a higher-intensity light source at the front of the light source, or a flood light source divided in at least two significantly different sections of intensity. These two sections provide a long dwell time and a higher peak.

[0091] The highest intensity and / or highest wavelength section is provided typically near the front of the LED UV light source, compared to the driving / application direction of the mobile unit. In other words, the higher intensity section of the LED UV light source reaches the coating first. As such a coating is first cured at a higher intensity and / or wavelength, and thereafter at a lower intensity or wavelength. The lower-intensity section is typically configured at the back of the light source.

[0092] Some examples and embodiments of a multiple section configuration of a flood light source of the invention are set out next.

[0093] In one embodiment, the flood light source is arranged as a LED board comprising multiple sections of different width and / or length. These sections can be switched on or off as required, optimising energy usage for the line width being applied. In one variant, sections of different width span the full lamp length, and the sum of section widths equals the lamp width (where “length” corresponds to travel direction and “width” to the applied line).

[0094] In one embodiment the LED UV light source sections have a uniform irradiance and wavelength, in which case the zoning is used solely for energy saving.

[0095] In one embodiment the LED UV light sources are configured into sections of varying widths, optimizing energy usage based on the specific requirements of the road marking application. Road markings, whether for indoor or outdoor use, have standard line widths that vary depending on the application, local regulations, and specific project requirements. For instance, indoor applications often require line widths of 50mm or 100mm.

[0096] In scenarios where the LED UV curing light source on the mobile unit has a total irradiance width of 150mm or 200mm, using the full width of the light source for a narrower 50mm line would result in significant energy loss. To address this, our UV light source controller could be equipped with a switch that enables or disables customizable sections of a certain width within the light source.

[0097] For example, if the application calls for a 50mm UV paint line, and the LED UV curing light source has a 150mm irradiance width, the controller can deactivate certain sections to reduce the effective light source width to 100mm. This adjustment ensures that the entire 50mm line is cured effectively while minimizing unnecessary energy consumption. Should the same application later require a 100mm UV line, the previously disabled section can be reactivated, expanding the curing width back to 150mm and ensuring full coverage and curing of the wider line.

[0098] For instance, if an application requires a 150mm line but the LED UV light source has a 300mm irradiance width, activating only 200mm of the light source’s width can reduce energy usage by approximately 33%. This allows the light source to deliver the necessary intensity across the entire 150mm line without wasting energy on areas that do not require curing. By enabling this sectioned configuration, the system significantly improves energy efficiency while maintaining the high performance and thorough curing needed for both indoor and outdoor road marking applications.

[0099] In a further specific embodiment of a surface marking system of the invention the LED UV light source comprises multiple sections of different lengths over the full width whereby the sections have a different intensity and wavelength. In an example embodiment of a surface marking system of the invention the LED UV light source comprises an LED UV section with a uniform intensity and a wavelength of mainly 405 nM (at the front of the LED UV light source) and partially 365 nM (typically at the back of the LED UV light source), and at the front of the LED UV light source further a higher-intensity section and a wavelength of 405 nM, and two separate intensity controllers (0-100%).

[0100] By way of example the system may comprise an air-cooled uniform LED UV flood light with two energy saving sections. The system comprises a traditional LED UV flood light section with a uniform intensity of 3500 mW / cm2, 470mm long and 300 mm wide, a wavelength of mainly 405 nM (at the front of the LED UV light source) and partially 365 nM (typically at the back of the LED UV light source) , and at the front of the LED UV light source further a higher-intensity section with an intensity of 6000 mW / cm2, 30mm long and 300 mm wide, a wavelength of 405 nM, two separate intensity controllers (0-100%).

[0101] The longer mixed wavelength LED UV flood light section is typically provided at the front of the light source (i.e. with the lowest wavelength at the back), whereas higher-intensity sections are typically located before the lower-intensity sections.

[0102] Energy consumption varies depending on the application, with the high-intensity sections requiring more power. For systems exceeding 3600 watts, energy distribution is managed across multiple power supplies, ensuring stable and efficient operations.

[0103] This enhanced configuration is particularly advantageous in applications where achieving a deep, thorough cure is critical, such as in high-traffic road markings or other demanding applications, such as highly pigmented coatings and faster application speeds. By providing an extra boost of intensity exactly where it is needed, these light sources ensure that even the more challenging UV coating applications are fully cured, enhancing the durability and effectiveness of the applied markings.

[0104] Portable power stations

[0105] Given the substantial energy requirements of UV light sources - recreating the controlled conditions of a controlled industrial conveyor belt on a mobile platform in non-controlled outdoor environments - traditional power solutions like alternators alone are often insufficient and not desirable in indoor settings. To address this, the invention incorporates high-capacity portable power stations. These portable power stations are rechargeable battery units that can be charged via solar energy or standard power outlets, delivering both AC and DC power for extended periods.

[0106] One of the key advantages of some of these portable power stations is their ability to handle high peak current draws, thanks to their high-quality pure sine inverters. They can deliver high continuous current, ensuring that the LED UV light sources receive consistent power during extended marking operations.

[0107] While these portable power stations are limited in capacity, their flexibility allows them to be used in conjunction with a traditional alternator connected to the engine. The alternator can recharge the portable power station while it is in use, effectively extending its operational time. Additionally, the modular design of these power stations means they can be quickly and easily exchanged for fully charged units, ensuring continuous operation without downtime. This system not only enhances the mobility and efficiency of the marking unit but also ensures that the power supply remains consistent, even in remote or urban settings where access to traditional power sources may be limited.

[0108] By integrating these interchangeable power sources, the mobile unit can maintain the high energy output necessary for optimal UV curing, while also offering the flexibility to adapt to various environmental and operational conditions. This makes it a robust and versatile solution for modern road marking applications, capable of delivering industrial-quality results in a compact, portable form.

[0109] In one embodiment of the invention the power supply for the high energy demands of UV is provided by one or more (portable) power stations. (Portable) power stations are a line of rechargeable portable batteries that charge via solar energy or power outlets and produce AC and DC power which lasts for several hours.

[0110] An advantage of some battery power stations is that they typically have a high peak current draw due to high-quality pure sine inverters, some are even able to reach 18000W / 80 A peak. Another advantage is that it can deliver similar amounts of continuous current to a standard electric plug, 3600W / 16 A.

[0111] These battery power stations can be used alone or in combination with a traditional alternator of an engine for recharging the portable power station.

[0112] In one embodiment the system utilizes a hybrid power supply that combines portable power stations with traditional engine-driven alternators. This approach ensures longer continuous power delivery for the high-intensity UV curing before having to change the support battery.

[0113] The portable power stations are equipped with high-quality pure sine inverters capable of handling high peak current draws. The stations can be recharged via solar energy or standard outlets, providing flexibility and sustainability.

[0114] The stations can handle high peak current draws and provide both AC and DC power. Modularity of power stations is a major advantage whereby power stations are designed to be easily exchanged for fully charged units, ensuring continuous operation without downtime.

[0115] Alternatively, to keep production going, low battery power stations can be exchanged for fully charged ones, while being recharged in the meantime.

[0116] Battery power stations can optionally be recharged via alternators. This allows the use of high-intensity UV light sources of any size: small focus lights, bigger flood lights or combinations thereof.

[0117] In one embodiment the system is designed to withstand the rigors of outdoor use, with durable components that can operate effectively in a wide range of environmental conditions, including extreme temperatures and varying humidity levels.

[0118] The materials used in the construction of the system are chosen for their resistance to corrosion, UV radiation, and other environmental factors, ensuring long-term durability and reliability.

[0119] The system's components are made of high-quality materials, such as corrosion-resistant metals and UV-resistant polymers, ensuring long-term durability and reliability and ensuring to withstand harsh conditions. The system is capable of operating effectively in extreme temperatures and varying humidity levels, making it suitable for use in diverse environments.

[0120] Quantified thermal management

[0121] Cooling management of the high-irradiance UV lamps of the invention is key as temperature affects the power and lifetime of UV LED diodes. Contrary to prior art systems the invention teaches a quantified air-cooling architecture for a high-irradiance LED flood lamp on a mobile unit, providing a performance cap on LED junction temperature during continuous operation. The air-cooling architecture combines better cooling fans and an optimised heat sink.

[0122] The air-cooling architecture features a large finned sink, high-CFM fans, high-k IMS and a ducted airflow that holds the LED junction temperature below 100 °C, preferably 90°C, at full power, in the specific mobile-UV context of the invention powered on a battery energy budget under given the dust ingress and weight issues.

[0123] In one embodiment, the system comprises an air-cooling assembly directing forced airflow across a finned aluminium heat sink thermally coupled to an insulated metal substrate (IMS) PCB carrying the LEDs. A thermal interface material (TIM) is disposed between the IMS PCB and the heat sink to ensure efficient thermal conduction. The lamp housing defines inlet and outlet apertures and internal guide rails or baffles which form a duct, ensuring that the majority of airflow is directed across the finned region and LED board rather than bypassing the assembly.

[0124] The airflow, thermal conductivity of the IMS PCB, and thickness and conductivity of the TIM are selected such that the LED junction temperature remains below 100 °C, preferably below 90 °C during continuous operation at the target irradiance. This specification provides sufficient stability to maintain optical output without degradation of LED lifetime.

[0125] Example (V13). Under ambient conditions of 25 °C, a configuration employing high-flow axial fans (> 110 m3 / h each), a finned sink of approximately 250 x 184 x 80-85 mm, an IMS PCB with in-plane thermal conductivity of « 16 W / m K, and a TIM layer « 0.5 mm thickness with thermal conductivity > 6 W / m K, together with housing apertures of 50-65 mm and internal guide rails of 3-5 mm, maintained maximum LED junction temperature below 90 °C at a lamp electrical input of ~0.9 kW. The glass and housing surfaces remained well below safety limits. Equivalent alternative components achieving the same thermal performance are envisaged.

[0126] As such the invention claims the following thermal management system.

[0127] In one embodiment of a system of the invention the cooling assembly is an air- cooling assembly configured to maintain an LED-junction temperature of at most 100 °C, preferably 90 °C during continuous operation at a peak irradiance of at least 2500 mW / cm2.

[0128] In one embodiment of a system of the invention the air-cooling assembly comprises at least one forced-air device providing a combined volumetric flow of at least 200 m3 / h across a finned heat-sink having a height of 70-95 mm and a planform area of at least 40 000 mm2.

[0129] In one embodiment of a system of the invention the LEDs are mounted to an IMS PCB with in-plane thermal conductivity of at least 10 W m-1K"1, coupled to the heat-sink by a TIM layer of 0.3-0.7 mm thickness and thermal conductivity of at least 5 W m-1K"1.

[0130] In one embodiment of a system of the invention a lamp housing defines inlet / outlet apertures of 50-65 mm and internal guide rails or baffles of 3-5 mm that duct airflow across the LED board and fins.

[0131] In one embodiment of a system of the invention the lamp array electrical input during operation is 0.6-1 .2 kW. The above air-cooling management of the LED UV array applies to units for indoor and outdoor environments. In larger outdoor units, the cooling assembly may alternatively or additionally comprise a closed liquid loop including a pump, coolant channels thermally coupled to LED substrates, and a heat-exchanger mounted to the vehicle.

[0132] In one embodiment of a system of the invention the system comprises a closed liquid loop including a pump, heat exchanger and coolant channels in thermal contact with the LED UV lamp array substrates.

[0133] In a further aspect the system of the invention provides a lamp module for mobile UV curing with a surface marking system of the invention, the lamp module comprising an LED UV array, an air-cooling assembly including a finned heat-sink and a ducted airflow path formed by a lamp housing, and an IMS PCB and TIM disposed between the array and the heat-sink, the module configured such that the LED junction temperature does not exceed 90 °C during continuous operation at a peak irradiance of at least 2500 mW / cm2.

[0134] Paint viscosity and temperature control

[0135] In one embodiment the system of the invention comprises a closed-loop heated hose and an optional insulated paint tank that maintain the temperature of the UV-curable coating between 25 °C and 40 °C.

[0136] Temperature control is a main aspect of UV coating applications, for ensuring constant optimal performance of the coating in terms of viscosity, curing efficiency, and durability, even under variable environmental conditions. UV coatings are sensitive to temperature fluctuations, which significantly impact their viscosity and, consequently, the application process and the final properties of the cured coating. Certain components within UV paint formulations — such as photoinitiators, monomers, and oligomers — can degrade or react undesirably when exposed to temperatures above approximately 50 °C for extended periods. This thermal degradation can lead to compromised quality and durability of the coating, resulting in issues such as reduced reactivity, incomplete curing, or altered mechanical properties. Maintaining the coating material below these temperatures is therefore favourable to preserve its integrity and ensure optimal performance.

[0137] The viscosity of UV coatings is directly influenced by temperature. At lower temperatures, the viscosity increases, making the coating thicker and more challenging to apply uniformly. This elevated viscosity leads to poor flow characteristics, resulting in uneven or non-uniform application. The increased resistance to flow can cause the coating to be applied inconsistently across the substrate, increasing the likelihood of applying it too thick in certain areas. Excessively thick coatings unevenly divided increase the risk of curing failures, as UV light may not penetrate sufficiently to cure the deeper layers. Incomplete curing can lead to poor adhesion, surface tackiness, and reduced durability of the coating.

[0138] High viscosity also impedes the coating's ability to properly wet the substrate, and to improve for a strong adhesion. Poor wetting can result in adhesion problems, potentially causing defects such as delamination or peeling, ultimately leading to premature failure of the coating.

[0139] Conversely, at higher temperatures, the viscosity decreases, making the coating more fluid. While this reduction in viscosity can ease the application process by allowing the coating to flow more readily, it can also lead to issues such as sagging, running, and difficulty in controlling the application thickness. Excessively low viscosity may cause the coating to spread beyond the intended area, leading to uneven film thickness and potential thinning in some regions. Thin coatings may not provide adequate coverage or achieve the necessary mechanical properties, negatively affecting the performance and durability of the cured coating.

[0140] Maintaining the coating material within an optimal and consistent temperature range impedes the application process. Typically, this optimal temperature range is between 25 °C and 40 °C. Keeping the coating within this temperature range ensures that the viscosity remains at a level conducive to uniform application, appropriate film thickness control, and effective curing.

[0141] The system is particularly well-suited for outdoor and indoor applications and even colder / non heated storage facilities, where environmental conditions can vary widely.

[0142] In controlled industrial environments, maintaining the appropriate temperature for UV coatings is more straightforward due to the stable ambient conditions and the availability of sophisticated temperature regulation systems. However, line marking applications, particularly those conducted outdoors, present unique challenges. The variability in environmental conditions, such as extreme heat in summer or cold in winter, can significantly impact the temperature of the coating during application.

[0143] In the field of line marking, temperature control options are limited, especially for smaller mobile units. While larger trucks and more complex setups, such as two-component epoxy trucks used in some parts of the USA for example, may offer temperature control systems, smaller units often lack the necessary energy resources to implement these features.

[0144] It is favorable not to heat the UV coating too intensely because certain components within UV paint formulations — such as photoinitiators, monomers, and oligomers — can degrade or react undesirably when exposed to temperatures above approximately 50 °C for extended periods. Excessive heating can lead to premature polymerization, reduced reactivity, or degradation of the coating material, compromising its quality and performance.

[0145] For this reason, the system avoids using airless flow heaters, which typically operate at high temperatures and rapidly heat the coating material. Such rapid and intense heating can potentially affect the UV coating due to thermal stress. Instead, the system employs heated hoses that gradually and uniformly warm the paint throughout the delivery system. This approach maintains the coating material within the optimal temperature range, ensuring consistent viscosity when the paint reaches the spray nozzle and optionally during recirculation if applicable.

[0146] The present invention addresses these challenges by incorporating a closed heated loop system consisting of a heated hose system — available for both high-pressure airless and low-pressure conventional spraying options — and, optionally, an insulated heated tank. The hose is heated for instance by means of electric heating elements that gradually heat the hose over its full length.

[0147] In one embodiment of a surface marking system of the invention the system further comprises a closed loop heated hose system and optionally a heated paint tank for maintaining the paint at a constant paint temperature of 20-50 °C, typically 30-40 °C, and a consistent viscosity. The closed loop heated hose system comprises a heated paint hose running from the paint tank to the nozzle of the applicator, and optionally a heated return hose from the nozzle back to the tank. The heated paint tank is double-sided, optionally insulated, and comprises internal heating pads.

[0148] The system employs heated hose assemblies where both the supply hose (typically 6 mm or 10 mm in diameter, equivalent to 1 / 4 inch or 3 / 8 inch) delivering the coating material to the application gun and, optionally, the return hose from the gun back to the tank are heated. By heating both hoses, the system ensures that the coating material maintains a consistent temperature throughout its circulation. The hoses may be wrapped with insulating material to minimize heat loss, thereby enhancing temperature stability during the application process.

[0149] The length of the hoses can range from 1 m to 45m, depending on the application and energy options.

[0150] The heated tank may comprise a closed lid to protect the UV paint against light and air contamination. The tank wall is optionally insulated in between the inner and outer walls of the double-sided tank. A heated hose is connected to the tank for recirculation of the paint.

[0151] The tank is typically made of plastic or stainless steel. The inside wall of the tank optionally has an epoxy coating to protect the wall against the chemical impact of the paint.

[0152] The tank and / or hopper is heated typically by heating pads provided in the double-sided wall. Typically 1 ,2 or 3 pads of 200-300W each are provided for smaller units. For bigger tanks custom made solutions are provided.

[0153] The tank is optionally interchangeable for fast paint (color) changes, or fitted with disposable liners.

[0154] To manage the flow of the UV coating material when not spraying, the system incorporates back-pressure valves or manual valves. These valves allow for slow, continuous recirculation of the UV paint even when spraying is paused. Maintaining a continuous flow of the UV material is favorable because it prevents the paint from sitting stationary in the hoses, which can lead to increases in viscosity or potential overheating within the lines due to prolonged exposure to heat. Continuous flow also helps maintain a consistent temperature throughout the system, ensuring optimal viscosity for uniform application when spraying resumes. Depending on the operator's preference and specific application requirements, these valves can be operated automatically or manually.

[0155] The tank design varies depending on the type of application.

[0156] Additionally, the tanks can be insulated with materials such as polyurethane (PUR) to further enhance temperature retention in colder conditions.

[0157] By integrating advanced temperature control mechanisms, including heated hoses and optionally heated tanks, this invention ensures that UV coatings are applied at their optimal, consistent viscosity ensuring optimal curing, and overall performance. These features result in high-quality, durable road markings, particularly in the challenging and variable conditions typical of line marking applications. Maintaining a stable material temperature not only improves efficiency and reliability of the coating process but also ensures that the final markings meet the highest standards of durability and safety.

[0158] An example of a heated hose customized insulated airless is as follows: voltage 230 V - 50 Hz, heating power 300 Watt per hose, 5m V* airless hose, max. working pressure 250 bar, temperature control 20-100°C (stepless).

[0159] An example of a heated hose standard airless is as follows: voltage 230 V - 50 Hz, heating power 1100 W, hose DN10 / 30m PU sheath, max. working pressure 250 bar, temperature control 20-60°C (stepless), weight 23kg, hose length 30m. Safety

[0160] In one embodiment the system of the invention comprises a UV-blocking shield positioned 5-40 mm above the marking surface so as to block at least 99 % of stray ultraviolet radiation.

[0161] Safety is of paramount importance when working with high-intensity ultraviolet (UV) light, particularly due to the potential harm that prolonged or intense exposure can cause to human skin and eyes. UV light at the intensities used in UV curing applications can pose significant health risks if not properly managed. In most industrial settings, UV light sources — whether LED or conventional — are typically enclosed or shielded to prevent direct exposure, thereby protecting operators and nearby personnel from harmful UV radiation.

[0162] By applying UV curing technology to line marking in both indoor and outdoor environments, the present invention extends UV curing applications into public and less controlled spaces, such as public roads and indoor facilities where other individuals may be present. While operators are required to use personal protective equipment (PPE), such as UV-resistant goggles and protective clothing, the risk of unintended exposure increases when UV curing is conducted in public more uncontrolled areas. Bystanders, including pedestrians, motorists, or workers adjacent to the application, may be unaware of the hazards and could inadvertently be exposed to intense UV light, especially if they are drawn to look toward the bright light source.

[0163] To mitigate these risks, the invention incorporates a UV protective shroud mounted or surrounding the LED UV light source for blocking and / or filtering UV radiation. This shroud is designed to minimize the escape of harmful UV radiation to an absolute minimum, effectively filtering out UV light from escaping into the surrounding environment. The protective shroud allows the necessary UV light to reach the coating being cured while shielding operators and bystanders from both direct and reflected UV exposure as much as possible. By containing the UV radiation within the immediate curing area, this design ensures that the curing process can be carried out more safely in public or shared spaces without compromising the effectiveness of the UV curing or posing health risks to individuals in the vicinity.

[0164] In one embodiment of a surface marking system of the invention the LED UV protective shroud comprises a top panel covering the LED UV light source, extending into front, back and side panels surrounding the light source and floating above the surface at 2-100 mm, preferably 5-40mm.

[0165] The shroud protects operators and bystanders from potentially harmful high- intensity UV exposure. The shroud not only improves safety (no unfiltered UV light escapes into the surrounding environment) but also still allows for effective visual monitoring of the curing process.

[0166] The shroud is made of UV-filtering materials, such as polycarbonate, PET-G, or (specially treated) plexiglass, with polycarbonate being the preferred material.

[0167] Polycarbonate is especially suitable for this application due to its inherent ability to filter out a significant portion of harmful UV radiation, particularly in the UV-B and UV-C ranges. It offers excellent fire-resistant properties, chemical resistance, and high optical clarity. Notably, polycarbonate is much stronger than glass of the same thickness, making it an ideal choice for situations where safety, visibility and durability are crucial. The material's optical properties ensure that visible light is effectively transmitted, allowing operators to monitor the curing process while maintaining a safe environment. By effectively filtering harmful UV radiation, the polycarbonate shroud minimizes the risk of UV exposure to operators and bystanders without impeding the performance of the UV curing process.

[0168] The protective shroud can make use of clear polycarbonate UV or alternatively colored polycarbonate UV to block the light even more. The shroud is preferably made of 1 mm to 3 mm thick polycarbonate UV, providing high clarity and durability while effectively blocking UV radiation.

[0169] The shroud is constructed around the LED UV light source and may include optional UV protective brushes. This design allows the light source's distance from the substrate to be adjusted as needed, with the shroud moving in unison to maintain effective UV shielding.

[0170] Traditionally, mainly brushes have been used around UV lights to block stray light, but this approach presents two significant issues. Firstly, the operator still needs to visually confirm that the UV curing light is functioning, especially since they must monitor both the paint application and, optionally, the distribution of glass beads. For outdoor applications, and optionally for indoor uses, the LED UV curing unit is integrated onto the same unit as the UV paint gun and the glass bead applicator, allowing the operator to see the light and ensure that the system is working properly.

[0171] Secondly, brushes cannot be brought completely to the ground at the front of the UV light where the curing process begins. If the brushes were to touch the uncured paint, they would disrupt the application, resulting in a damaged line. To address this, the invention applies a system of brushes on the sides of the UV light, with optional placement at the back and minimal length at the front. This configuration maintains a safe distance between the brushes and the uncured paint, ensuring that the application remains intact while still providing UV protection.

[0172] Moreover, the shroud is designed to allow the operator to adjust the height of the UV curing light source. The adjustability allows to optimize the intensity and focus of the UV light based on the specific requirements of the application, ensuring that the curing process is both effective and safe. Advanced control mechanisms

[0173] In one embodiment, the system integrates advanced control mechanisms to ensure precise UV coating application. These controls replicate, as far as possible, the conditions of a controlled industrial environment while operating in variable outdoor settings. By combining industry-standard spraying equipment with electronic controls, the mobile unit delivers consistent, high-quality finishes that approach industrial standards, even in uncontrolled field conditions.

[0174] The mobile unit is designed to achieve a highly consistent and controlled UV coating in the uncontrolled nature of this application. By using industry-standard spraying technologies such as airless systems (including double diaphragm airless pumps and bellow pump airless systems) or conventional pressure tank spraying with an optional software-controlled flow meter, the system ensures that the applied layer thickness is consistently accurate. This combination not only minimizes the risk of uncured applications but also reduces the likelihood of errors, resulting in a low failure rate and a professional, industry-like finish.

[0175] In one embodiment of a system of the invention an electronic controller governs the traction-drive speed so that the travel speed varies by no more than ±5 % of a set value during curing.

[0176] In one embodiment the mobile units are equipped with speed control systems to enhance application consistency and curing efficiency. Implementing speed control allows these mobile units to replicate the continuous, set-speed conveyor belts commonly used in industrial UV curing environments. This replication ensures consistent application rates and uniform curing, eliminating variability caused by operator speed inconsistencies during manual operation.

[0177] In one embodiment of a system of the invention a flow-meter and feedback controller maintain a constant volumetric flow rate of the UV-curable coating during application. In a specific embodiment an electronic controller monitors the coating flow rate, travel speed and LED output and adjusts parameters in real time to maintain a target energy dose per unit length.

[0178] This setup allows the operator precise control over the actual amount of paint being applied which supports maintaining a consistent layer thickness.

[0179] The flow meter continuously monitors and adjusts the paint flow rate in real time, and the software controller displays the application in real time based on the speed of the mobile unit and other variables such as line width, ensuring that the correct amount of paint is consistently applied across the surface.

[0180] This level of control not only ensures that the coating is applied at the correct thickness but also significantly reduces the risk of errors and variations that are common in less controlled systems, such as manual roller applications. By providing such precise control, the system delivers a professional, industrystandard application, ensuring that the final product is durable, fully cured, and meets the highest quality standards.

[0181] In one embodiment of a surface marking system of the invention the system comprises an electric height adjustment system for optimizing the distance between the spray nozzle and the surface and for controlling the line width.

[0182] Via the feature of electric gun height adjustment the operator can maintain and configure the optimal distance between the spray nozzle and the application surface, without interrupting the application ensuring correct line width.

[0183] The electric gun height adjustment feature optimizes the distance between the spray nozzle and the application surface. This system ensures consistent line width by maintaining the correct spray height without having to interrupt the operation, regardless of surface variations or operator handling. By automating this aspect of the process, the operator or support personnel can remain at a safe distance from the application section, reducing exposure to potentially hazardous environments while ensuring precise line application. This system is advantageous on smaller mobile road marking systems.

[0184] An (electric) height adjustment system can also be applied to the LED UV light source unit for adjusting the height of the light source compared to the surface to be marked.

[0185] In one embodiment, to further facilitate precision and control of the application process, the system integrates a dual or triple laser line projection system mounted at the rear of the spray gun, providing visual cues for maintaining an accurate line width during the marking process.

[0186] The laser system visually displays the intended width of the line on the surface behind the spray application. The operator can visually monitor these laser guides, ensuring that the application remains within the desired parameters, resulting in consistent and accurate line markings. This combination of automated height adjustment and visual laser guidance significantly improves the reliability and precision of the line-marking process.

[0187] Line width in spray applications is influenced by several factors, including the height of the spray gun above the surface, the type and size of the nozzle or spray tip, the viscosity of the paint, the spray pressure, and the speed of the application unit. Environmental conditions, particularly ambient temperature, can significantly affect these factors — most notably the paint's viscosity - during the application.

[0188] As temperatures fluctuate throughout the day, the viscosity of the paint changes correspondingly. To maintain a consistent line width under these varying environmental conditions, it is efficient and practical to have the ability to adjust the height of the spray gun relative to the surface. By modifying the gun height, the operator can compensate for changes in paint viscosity and other environmental factors without needing to change the nozzle or adjust the spray pressure frequently. Raising the spray gun increases the distance between the nozzle and the surface, resulting in a wider spray pattern and broader line. Conversely, lowering the spray gun decreases this distance, producing a narrower spray pattern and line.

[0189] In one embodiment of a surface marking system of the invention and as an enhanced safety feature, the system comprises an overspray suction system configured as a spray booth surrounding the spray gun and nozzle, and equipped with suction mechanisms to capture overspray particles during paint application.

[0190] The overspray suction system is designed to minimize the dispersion of paint particles during application. The system is particularly beneficial in indoor settings, where controlling overspray is critical for maintaining a clean work environment and reducing environmental contamination and health risks related to UV spray applications.

[0191] Integrated into the marking system, the suction system can be activated as needed based on specific application requirements. Positioned near the spray gun / nozzle, it creates a controlled section that captures and extracts overspray particles before they can disperse into the surrounding environment. By effectively reducing the amount of airborne paint particles, the system helps prevent unintentional deposition on unintended surfaces and minimizes exposure risks to operators and bystanders.

[0192] In one embodiment the coating layer is applied by means of airless spraying.

[0193] Multi-set paint application and curing in a single pass

[0194] The system of the invention enables the application of thicker tension-free coatings by means of multiple, preferably double, thin layer application in a single pass, whereby the thinner layers are applied on top of one another. This typically applies for high-pigmented coatings comprising 5-13% of pigment content and having a total coating thickness of 250 up to 400-500 pm. The individual layers preferably have a thickness below 250 pm.

[0195] This ensures that the coating is fully cured and avoids possible tension and stress in a layer which would otherwise be applied and cured in one thick coating. A multi-layered single pass coating is less brittle compared to a single layered coating of identical thickness.

[0196] In this way multiple thinner coating layers are applied on top of one another, instead of applying one thicker layer. The system hereby avoids brittleness and tension in thicker coatings.

[0197] A multi-layered single pass coating is applied by consecutively applying and curing layers on top of one another in a single pass. In the example of double layers, the first layer is typically gelled and the second layer is fully cured. This ensures that the layers are blended while cured.

[0198] Multi-layered single pass coating is specifically advantageous for high-pigmented systems achieving coating thickness of 450-500 pm.

[0199] In a further embodiment of a system of the invention the system comprises multiple sets of a paint applicator and an LED UV lamp array arranged downstream one another for consecutively applying and curing multiple coating layers in a single pass.

[0200] The multiple layers are applied and cured consecutively meaning one after another immediately and without an interruption, that is one layer on top of another layer. Thereto multiple sets of a paint applicator and an LED UV lamp array are mounted or arranged downstream one another on the surface marking system.

[0201] In a specific embodiment a multi-section LED UV lamp array may function as a multiple set of an LED UV lamp array in the above sense whereby the multi- sections are switched on / off accordingly and function as separate sets. Dedicated controllers enable the separate scaling of wavelength and section size, and this by wavelength, unit size, power pack abilities, etc.

[0202] In a specific embodiment the system is arranged to apply two layers of UV-curable coating in a single pass. In one embodiment the UV-curable coating comprises two layers of identical UV-curable paint (having identical pigmentation content etc.). In another embodiment the UV-curable coating comprises two layers of nonidentical UV-curable paint (having different pigmentation content etc.). In the case of non-identical coating paint, the system may comprise two paint tanks or a split paint tank for housing different paint compositions.

[0203] In one embodiment of a system of the invention the system comprises a first paint applicator (6a) and a first LED UV lamp array (4a) configured for applying and curing a first coating layer, and a second paint applicator (6b) and a second LED UV lamp array (4a) arranged downstream of the first, and configured for immediately applying and curing a second coating layer onto the cured first coating layer.

[0204] In one example of a system of the invention a thicker surface marking up to 500 pm is applied in two thinner coating layers on top of one another in a “double one pass” application and curing. Two surface markings, one above the other, are applied and cured in one pass. As the system moves over the surface, a first coating up to 250 pm is applied and cured or gelled, immediately followed by applying and curing a second UV-curable coating up to 250 pm on top of the freshly applied and cured first coating in one and the same pass as the system moves over the surface. Optional glass beads can be dropped onto the surface of the second coating before curing.

[0205] In a specific embodiment the coating layers each have a thickness of 220 pm. The system cures surface markings up to 500 pm. In one embodiment the first and second layer have a thickness of 220 micron and comprise 6% of TiO2. Optionally the pigment content of the first layer is lower than the pigment content of the second layer. The first layer is gelled by LED UV light of 405 nM to guarentee deep curing of the layer.

[0206] Glass beads are optionally dropped onto the surface of the first layer, e.g. 150-200 g / m2 with a size of 250-850 micron. Glass beads are optionally dropped onto the surface of the second layer, e.g. 250-400 g / m2 with a size of 250-850 pm.

[0207] Optically transmissive components

[0208] In one embodiment of the invention, and relevant for reflectivity in outdoor or off- highway purposes, the system further comprises a micro bead applicator or dispenser (pressurized or non-pressurized) to obtain retroreflectivity. The optically transmissive components, such as micro beads, glass beads, reflect light back to the source, e.g. car headlights, for better visibility. This is specifically beneficial for outdoor road markings.

[0209] In one embodiment of a surface marking system of the invention the system comprises a dispenser for dispensing optically transmissive components, wherein the dispenser is configured in between the paint applicator and the LED UV light source, whereby in direction of movement of the surface marking system, the dispenser drops optically transmissive components on the surface of a coating layer before UV curing.

[0210] Contrary to known systems, such as disclosed in US10822755B1 , the retroreflective optically transmissive components of the present invention, such as glass beads, are not required for effective UV curing. The retroreflective materials are only required to meet regulatory standards concerning road safety. In one embodiment of the present invention, low pigmented UV coatings comprise retroreflective optically transmissive components that are exposed on the surface of the coating.

[0211] In one embodiment the optically transmissive components comprise micro beads, such as glass or quartz beads, and / or angled glass particles.

[0212] Coated optically transmissive components

[0213] In one embodiment of the invention the optically transmissive components comprise coated optically transmissive components. The coating of the optically transmissive components is a UV coating. When the coating is worn-off light can enter into the optically transmissive components and reflect against the coating on the opposite side of the components.

[0214] The coated optically transmissive components are especially applied or dropped onto the surface of the coating layer for an improved retroreflective effect and to comply to standard regulations of road safety.

[0215] In one embodiment the optically transmissive components comprise partially coated optically transmissive components. The advantage of only partially coating the optically transmissive components, for example glass beads, is that when they are exposed on the surface of the coating layer, an immediate retroreflective effect is achieved where light enters the exposed non-coated part of the optically transmissive components. This effect is contrary to fully coated glass beads where the coating must be abradable and needs to be worn-off first before acquiring a retroreflective effect.

[0216] When optically transmissive components are coated on one side for example, at least 50% of the optically transmissive components will result in an immediate retroreflective effect when the components are partly exposed on the surface of a marking. The optically transmissive components comprise micro beads, such as glass or quartz beads, and / or angled glass particles. The coated optically transmissive components comprise coated micro beads, such as coated glass or quartz beads, and / or coated angled glass particles.

[0217] The optically transmissive components preferably have a size of 250-850 pm.

[0218] In a preferred embodiment a mix of coated optically transmissive components, preferably 60%, and standard optically transmissive components, preferably 40%, are dispensed.

[0219] In another preferred embodiment the drop-on coated optically transmissive components are embedded in the coating layer to a depth of approximately 40- 60% of their volume and have a size between 150-650 pm.

[0220] In one embodiment of the invention, low pigmented UV coatings comprise a mix of coated and non-coated optically transmissive components to comply with regulatory safety standards on retroreflectivity of line markings. The coated optically transmissive components are present at least at the surface of the coating before curing. Therefor the concentration of pigment (e.g. TiO2) in the coating layer is not crucial for high retroreflectivity and can be kept very low for a deeper and more effective curing of the coating layer.

[0221] In one embodiment the dispenser is a drop-on bead dispenser, and 40-60% of the optically transmissive components are coated on the surface with a retro-reflecting pigment for applying to road safety standards regarding reflectivity. The coating of the optically transmissive components is abradable. The material of the optically transmissive components is translucent / transparent. The optically transmissive components are optionally made of glass and the retro-reflecting pigment is titanium dioxide. In one embodiment the optically transmissive components are coated with a concentration of titanium dioxide of at least 30% by weight, preferably at least 45% by weight, more preferably at least 60% by weight. The coating of the optically transmissive components preferably comprises 1 -10 g of titanium dioxide for every 100 grams of optically transmissive components, preferably 2-6 g, ensuring full coverage and maximum retroreflectivity.

[0222] In one embodiment the coated optically transmissive components are drop-on beads. The coating layer may comprise a drop on mix of coated and uncoated optically transmissive components. In another embodiment the optically transmissive components are premixed in the UV paint.

[0223] According to the invention coated optically transmissive components provide high light reflections while saving on TiO2 in the UV paint coating layer itself. The low TiO2 concentration in the UV paint providing very poor opacity and whiteness for reflection is hereby compensated to meet regulatory standards.

[0224] The coated optically transmissive components are micro beads having a size ranging from 150 to 12000 pm, preferably 150-1800 pm. The surface of the micro beads is coated with a layer of TiO2.

[0225] The micro beads are prefereably made of glass. Alternatively thermoplastic micro beads are coated, or micro beads made of other materials.

[0226] UV-curable coating of microbeads

[0227] The UV-curable coating serves as a durable and strong adhesion promoter, improving the bond between the micro-beads and the different road marking compositions. The coating material can be a UV-curable resin that may optionally include pigments such as titanium dioxide (TiO2) to impart color or enhance reflective properties. By focusing on adhesion promotion through the UV-curable coating, the beads maintain their retro-reflective properties over time due to improved adherence to the road marking material.

[0228] UV-curable adhesion coatings offer flexibility in formulation to suit specific application requirements. For example, the coating can be tailored to include adhesion promoters, crosslinking agents, and optional pigments to optimize performance under various conditions. The composition ensures a balance between durability, adhesion, and improved retroreflectivity, making it suitable for demanding road marking applications, including those involving thermoplastics or cold plastics.

[0229] In one embodiment the micro-beads comprise a transparent UV-curable coating in an amount ranging from 0.1% to 5% by weight of the micro-beads. In another embodiment the UV-curable coating includes pigments, such as titanium dioxide (TiO2).

[0230] The invention also relates to the use of UV-cured coated micro-beads according to the invention in a road marking process, whereby the UV cured coated micro are mixed into a road marking composition or are dropped onto an applied road marking.

[0231] When road markings are applied, the coated glass beads are typically dropped onto the uncured marking material. Preferably, the beads embed partially into the surface layer of the road marking, ensuring optimal positioning for retroreflective performance while maintaining strong adhesion to the marking composition.

[0232] By being exposed to weather conditions and traffic, the UV-cured coating on the exposed parts of the micro-beads will wear off, thereby allowing light to enter these micro-beads and being reflected back. When exposed to weather and traffic, the UV-cured coating on the micro-beads gradually wears off. For unpigmented coatings, this has minimal impact on reflection, allowing the micro-beads to provide immediate retroreflective properties upon application. In contrast, coatings with optional pigments may slightly reduce initial retro reflectivity, but as the coating wears away, more light enters the beads, progressively enhancing their reflective performance. This process ensures sustained visibility and long-term durability of the road markings.

[0233] When the UV-cured coated micro-beads are dropped onto the applied road marking, as in known systems, they become partially embedded in the road marking material. Depending on the size of the glass beads, they typically embed 40% to 60% into the marking. The UV-curable adhesion promoter coating enhances the bond between the beads and the road marking material, ensuring that the beads stick better and remain better attached over time. This improved adhesion reduces bead loss due to traffic wear and environmental factors, maintaining the retro-reflective properties of the road marking for a longer period.

[0234] When the UV-cured coated micro-beads are mixed into the road marking composition, such as thermoplastics or cold plastics used as fillers, they are incorporated throughout the material. In applications involving thermoplastics, which are often heated to temperatures 180-240 degrees Celsius, the UV-curable coating provides better thermal stability. Unlike traditional coatings, the UV-cured adhesion promoter withstands the high temperatures and the shear forces experienced during mixing in tanks. This ensures that the beads maintain their adhesion-promoting function without degradation. As the road marking layer wears over time due to traffic and environmental exposure, the embedded beads gradually become exposed, continuing to enhance the retro-reflective properties of the marking.

[0235] Optionally, these adhesion-promoting UV-curable coatings can include pigments to enhance the reflectivity or other optical or visual properties. The UV-curable adhesion coating can be pigmented to improve retro-reflection over time by including pigments such as titanium dioxide (TiO2), and / or yellow pigments and / or orange pigments and / or other pigments. In this way, the coated micro beads can contribute to enhanced visibility and brightness of the road markings. This pigmentation is beneficial in both drop-on and intermix applications, as it provides an additional means of maintaining or improving retro-reflectivity as the road marking material wears.

[0236] In one embodiment the UV-curable coating composition comprises:

[0237] • 10 to 20 % by weight multifunctional acrylate oligomers;

[0238] • 5 to 10% by weight additional polymers based on methacrylates with molecular weight 30.000-40.000 g / mol and a glass transition temperature between 45-55 °C;

[0239] • 25 to 35 % by weight multi and / or mono-functional monomers;

[0240] • 1 to 5% by weight phenyl phosphinate photoinitiators ,

[0241] • 0,1 to 2 % by weight supplementary photoinitiators for enhanced LED / UV light sensitivity;

[0242] • 0,1 to 3,0 % by weight defoamers based on organic polymers, silicone free and silicone based to prevent air entrapment;

[0243] • 0,1 to 0,5 % by weight polymerisation inhibitor or stabilizer for radically curable resins;

[0244] • 0,1 to 1 ,0 % by weight polymeric, silicone-free and silicone containing flow and levelling agents for better substrate wetting;

[0245] • 0,5 to 2,0 % by weight waxes based on modified Polypropylene - micronized D50% in pm 5-10 for surface protection;

[0246] • 25 to 45 % by weight pigments for color and opacity;

[0247] • 0,5 to 5 % by weight fillers or extenders for opacity and mechanical properties;

[0248] • 2-6% by weight acrylated amine synergist for enhanced Cure characteristics and adhesion properties.

[0249] In one embodiment the coated optically transmissive components are dropped on the surface of the uncured coating layer after the latter is applied on the surface. The layer is then cured. The optically transmissive components are intended to embed into the paint to a depth of approximately 50-60% of their diameter, ensuring optimal retroreflectivity. This precise level of embedment is important; it allows the optically transmissive components to be firmly anchored within the coating while maintaining their ability to reflect light back towards oncoming traffic. If the optically transmissive components are embedded too deeply (beyond 60% of their diameter) they become less effective, as they are partially covered by the paint layer. Conversely, if the embedment is too shallow (less than 50%) the optically transmissive components may dislodge easily under traffic conditions, reducing the overall longevity and effectiveness of the marking.

[0250] The coating on the non embedded part of the optically transmissive components is worn off by traffic running over them. As such, the light hits the abraded optically transmissive components on the surface of the coating layer, travels through the glass bead and reflects back against the coating of the optically transmissive components.

[0251] The optically transmissive components used typically range in size from 150 to 1200 microns. Smaller beads enhance initial retroreflectivity and provide a smoother finish, while larger beads offer greater durability and superior light reflection, particularly in high-traffic areas. The choice of bead size balances retroreflectivity, durability, and surface adhesion to ensure optimal road visibility under varying conditions.

[0252] The UV-curable coating applied to the optically transmissive components contains a high concentration of TiO2, typically between 30% by weight to 60% by weight and 60% by weight or more, to achieve the necessary reflectivity for white road markings.

[0253] For every 100 grams of optically transmissive components, approximately 2 to 4 grams of this high TiO2 content coating is applied, ensuring full coverage and maximum retroreflectivity. The high TiO2 content in the coating means that when these beads are applied to the road surface, they provide significant retroreflectivity even as the base paint doesn’t have a high content of pigments. The drop on beads are a mix of coated optically transmissive components with uncoated beads with a ratio of e.g. 40% uncoated beads and 60% coated beads.

[0254] The drop-on optically transmissive components are partially embedded into the coating layer typically into the paint to a depth of approximately 50-60% of their diameter, depending on the size.

[0255] By coating the optically transmissive components with high-TiO2coatings, the TiO2content in the UV paint itself can be reduced to < 1 wt% while still meeting or exceeding regulatory retroreflectivity standards.

[0256] In one embodiment of the invention, the UV coating comprises a TiO2 in the amount of 1 % by weight or lower. Known marking systems have a TiO2 content between about 4-15% by weight.

[0257] An additional advantage is that by coating part of the optically transmissive components with e.g. 40% or more TiO2, an extreme amount of TiO2 can be saved in the entire application. It is well known that TiO2 is extremely harmful to the environment. Through this solution, the UV system becomes more sustainable and less environmentally demanding than other systems.

[0258] Some examples of mobile units

[0259] In a first example an electric walk behind UV mobile unit comprises the following components: a screw compressor, KTC compact 2, delivery 31 Ol / min at 6 bar, energy draw: 2,7 KW; an airless double diaphragm pump, processable materials: water-borne, solvent-borne, abrasive, shear sensitive, sensitive to moisture, maximum material pressure: 250 bar (at 6 bar air inlet), volumetric flow per double stroke: 10 cm3(2L / min flow per minute), transmission ratio: 40:1 , material temperature: 10-80 °C; a high-intensity LED UV curing light, 250 mm long, 150mm wide, 405 nM wavelength (150mm) and 365 nM (100mm), 405 nM LED diodes with 60 degrees glass lenses, 365 nM LED diodes with 30 degrees glass lenses, intensity 3000 mW (405 nm), 2000 mW (365 nM) at 30mm, air cooled, energy needed: 3000 W at 100% power; a heated hose / gun, 1 x 5m V* airless hose with 300 Watt heating power per hose (230 V - 50 Hz), max. working pressure: 250 bar, temperature control: 20 - 100 ° C (stepless), manual airless guns with recirculation (+ recirculation valve); an electric height adjustment, manually operated electric linear module with DC motor; engine: electric capacity: 2,1 Kwh per battery each, rated power: 3600 W, peak power: 18000W; two IG1 batteries in frame, one for compressor, one for UV light source, heating and height system.

[0260] In a second example an engine driven walk behind UV mobile unit comprises the following components: a compressor: optional for pressurized glass beads; a converted electric bellow pump airless; processable materials: water-borne, solvent-borne, abrasive, shear sensitive, sensitive to moisture; electric drive: Graco Mark VII pump engine with customized adaptor for pump section; pump section: Graco 35:1 Bellow pump with UV packings into protective shroud; max. material pressure: 220 bar; volumetric flow per double stroke: approx.. 110 cm3(approx. 6 l / min); UV lamp: higher-intensity LED UV curing light, 250mm long, 150mm wide, 405 nM wavelength (150mm) and 365 nM (100mm), 405 nM LED diodes with 60 degrees glass lenses, 365 nM LED diodes with 30 degrees glass lenses, intensity 3000mW (405 nm), 2000mW (365 nM) at 30mm, air cooled, energy needed: 3000W at 100% power, heated hose / gun, 1 x 7,5m 3 / 8” airless hose Heated hose with 450 Watt heating power per hose (230 V - 50 Hz), max. working pressure: 250 bar, temperature control: 20 - 100 ° C (stepless), manual airless guns with recirculation (+ recirculation valve); electric height adjustment: manual operated electric linear module (hard-anodized, ball bearings carriage length 150 mm) with DC motor; engine: electric (battery), 2 x Instagrid IG1 , 1 for compressor 1 for UV lamp, heating and height system, capacity: 2,1 Kwh per battery each, rated power: 3600 W, peak power: 18000W, battery in frame: 2 IG1 batteries in frame.

[0261] In a third example an engine driven UV ride on mobile unit for outdoor application comprises the following components: a compressor: rotary vane compressor; motor power (hp / kW) 7.5 HP / 5.5 kW; pump: double diaphragm airless : Wagner Cobra 4025; processable materials: water-borne, solvent-borne, abrasive, shear sensitive, sensitive to moisture; air inlet pressure: 2.5-6 bar; max. material pressure: 250 bar (at 6 bar); volumetric flow per double stroke: 25 cm3(5L per minute flow); LED UV curing: a LED UV high-intensity curing light; 500mm long, 300mm wide; 405 nM wavelength; intensity 4500 mW / cm2, air cooled; energy needed: 2 x3600W (total 7200W); hoses / guns; heating power: 1100 W (230V); hose: DN10 / 30 m PU sheath (working pressure: 250 bar); temperature control: 20 - 60 ° C (stepless); automatic airless guns with recirculation valves; electric height adjustment: manual operated electric linear module (hard-anodized, ball bearings carriage length 150 mm) with DC motor; glass beads applicator: Pressurized bead applicator; engine: Vanguard 18HP with supporting exchangeable power station; 2 x EcoFlow DELTA Pro 3; capacity: 4 Kwh each; rated power 4000W (up to 6000W via X-Boost); recharging via AC charging input 200-240V~12.5A,2900W max.

[0262] Method of marking a surface

[0263] In a second aspect the invention relates to a method of marking a surface with a surface marking system according to any of the preceding claims, the method comprising the steps of: a) moving a surface marker along the surface at a travel speed of at least 1 km / h and in a single pass: b) applying with the paint applicator a UV-curable coating layer up to 500 pm to the surface; and c) exposing the coating to the LED UV lamp array and curing or gelling the coating.

[0264] In one embodiment the coating layer is fully cured and hardened within 60 seconds of application.

[0265] In one embodiment of a method of the invention step b is followed by the step of dispensing drop-on glass beads or optically transmissive components onto the surface of the final coating layer before curing. In a specific embodiment of the invention a method of marking an indoor surface is provided, the method comprising the steps of: i) dispensing a UV-curable white coating while travelling at a speed of at least 1 km h-1, and ii) exposing the coating to the LED UV lamp array so that the coating is fully cured within 60 seconds of application.

[0266] In another specific embodiment of the invention a method of marking an outdoor road surface is provided, the method comprising the steps of: i) dispensing the UV-curable road-marking composition and glass beads while the system travels at a speed of at least 2 km h-1 , and ii) curing the composition in one pass to form a fully hardened coating layer having a Konig hardness of at least 100 s within 60 seconds of application.

[0267] An example of a method for applying a thick UV linemarking with a thickness between 400-700 micron on an outdoor surface is set out here below.

[0268] Applying an UV coating layer (containing e.g. 0-4% by weight TiO2) by airless spraying (airless pump pressure at 100-140 bar) onto an outdoor surface (e.g. asphalt road) with a thickness between 400-700 micron. A closed loop system with heated hose ensures a temperature of 25-40 degrees, maintaining a stable viscosity for the UV paint. Dispensing drop-on optically transmissive components (mixed of e.g. 60% highly pigmented / coloured and 40% standard optically transmissive components), onto the freshly applied UV coating layer (at a rate of e.g. approx. 0,4-0,75 kg / m2) for improved visibility and durability. The optically transmissive components aim for an embedment in the wet material of 30-60% for optimised retroreflective results. The optically transmissive components have an approximate size, mixed from 200-850 micron. Curing the linemarking material using an LED UV light source (wavelength 405 nM and 365 nM) that passes over the applied coating layer at a distance of 40mm. The curing process is initiated immediately after the application of the UV coating layer and optically transmissive components. In an example, the strength of the LED UV flood light source and curing speed are optimized based on the thickness of the UV linemarking material. The LED UV light source has a uniform strength of approx. 3500 mW / cm2at approx.20mm (at 75% of power) providing a dose of 2500-3000 mJ / cm2, allowing us to have application speeds up to approx. 3km / h. The light source has a protective hood with brushes to filter and block the UV light as much as possible for the safety of operators and road users.

[0269] In an example, the energy consumption of the light source is 7200W (split 2X3600W) at 100% power. This is supplied by two power stations with each a capacity of 4000Wh, with each 230V / 16A, 4000W capacity total (Surge 8000W). The batteries can be charged by the engine of the mobile marking machine (Support 12V / 24V battery, 8A) or via an alternator on the machine to extend the use or be exchanged and recharged with AC charging input at 2900W Max, 230V-12.5A or solar charge (charge input 1600W Max, 11 -150V, 15A).

[0270] In an example, the strength of the LED UV flood light source and curing speed are optimized based on the thickness of the UV linemarking material. The LED UV light source has a uniform strength of approx. 3500 mW / cm2at approx..80% of power) providing a dose of 2500-3000 mJ / cm2, allowing curing speeds up to approx. 3km / h. The light source uses 3000W (at. Approx. 80% of power).

[0271] The mobile curing unit has an optional electric transaxle drive (gear Ratio: 33.7:1 , Motor: 600W-DC 24V-2600 RPM), to ensure that the operator maintains a continuous speed during the curing process, to ensure a consistent curing speed. This creates a continuous process similar to UV curing applications in controlled industrial UV applications. The optional electric transaxle drive comes with a controller on the steering bar, so the operator can control everything during the application. The unit comes with two pre-set speeds (for gelling and full curing speeds), a free speed functions (operator via a thumb throttle), reverse / front function, a horn, an emergency stop, battery indicator and the possibility to disconnect should the battery be empty to be able to still move the unit. The LED UV light source unit is 25cm (front to back) long and 15cm wide, and has two sections with different wavelengths. The LED UV light source comprises an aluminium housing with a 3 mm quartz glass protective panel, IP67 metal connection panel with LED 405 nm (front) mixed with 365 nm (back) with narrow beam glass dome LEDs divided into sections every 5 cm each with 95 LEDs per section, sections can be controlled individually or together via controller, 12 VDC 60 mm x 60 mm cooling fan.

[0272] The front section of the LED UV light source emits a wavelength of 405 nM for deep curing, length 15cm, (optionally 20cm), strength 3000 mW / cm2at 40mm distance (LEDS with narrow beam lenses), LEDs divided into 5 subsections, 5 cm each with 95 LEDs per subsection, subsections can be controlled individually or together. Used to deep cure the UV material applied on the substrate.

[0273] The back section emits a wavelength of 365 nM for top curing, length 10cm, (optionally 5, strength approx. 2400 mW / cm2at 40mm distance (LEDS with narrow beam lenses), LEDs divided into 5 subsections, 5 cm each with 95 LEDs per subsection, subsections can be controlled individually or together. Used to deep cure the UV material applied on the substrate.

[0274] The LED UV light source unit has a protective hood with brushes to filter and block the UV light as much as possible for the safety of operators and road users.

[0275] The power of the mobile unit is 100% supplied via two expandable power stations reworked in the frame. Each power station has an output voltage of 230 V (AC) I 50 Hz, a rated capacity of 2.1 kWh, a power output of 3.6 kW (16 A) and a peak power output of 18.0 kW (80 A). The power supply is configured as follows: on the UV paint application unit: one power station is used to supply the compressor of electric power in order to feed the air motor of the double diaphragm pimp, and one power station is used to supply tank / hose heating, electric height set up of necessary power. On the UV curing unit: one power station is used to supply the LED UV light source of the necessary power, and one power station is used to supply the optional electric transaxle drive. The power stations can optionally be exchanged by a sliding mechanism to avoid downtime during charging

[0276] In one embodiment a method for applying and UV curing an outdoor thin coating layer is provided. The method comprises the steps of: a) applying a coating layer having a thickness between 300 and 400 micron with a paint comprising 2-10% by weight pigment; b) optionally dispensing drop-on coated optically transmissive components onto the surface of the coating layer; and c) curing the coating layer using an LED UV light source.

[0277] An example of a method for applying an outdoor thin UV linemarking with a thickness between 300-400 micron in an application of an off-highway base coat is set out here below.

[0278] Applying an UV linemarking material (containing 4-8% by weight pigments such as TiO2) by airless spraying (airless pump pressure at 90-140 bar) onto an off- highway road surface with a thickness from 150-400 micron. A closed loop system with heated hose ensures a temperature of 25-40 degrees, maintaining a stable viscosity for the UV paint. Drop-on optically transmissive components are optionally applied onto the wet UV material (at a rate of e.g. approx. 0,2-0,45 kg / m2) for improved visibility and durability. The optically transmissive components aim for an embedment in the wet material of 30-60% into the wet material for optimised retroreflective results. The optically transmissive components have an approximate size, mixed from 150-650 micron. Curing the linemarking material using an LED UV light source (mixed wavelength, 405 nM and 365 nM) that passes over the applied material at a distance of 30mm. The curing process is initiated immediately after the application of the UV material and optically transmissive components on the road surface.

[0279] In an example, the LED UV flood light source strength and curing speed are optimized based on the thickness of the UV linemarking material. The LED UV light source has a dual wavelength (405 nM and 365 nM), where the 405 nM has an intensity of approx. 4000 mW / cm2at approx.30mm (at approx. 80% of power, the 365 nM has an intensity of 2500 mW / cm2providing a dose of 2500-3000 mJ / cm2, allowing us to have application speeds up to approx. 3km / h. The light source has a protective hood with brushes to filter and block the UV light as much as possible for the safety of operators and road users.

[0280] In an example, the energy consumption of the light source is 7800W (split 2X3900W) at full power. This is supplied by 2 expandable power stations with each a capacity of 4096Wh, with each 230V / 16A, 4000W with 6000W max in expanded set up. (Surge 8000W). The batteries can be charged by the machine’s engine (Support 12V 8A max. / 48V 20A max) or with an alternator on engine to extend the use OR be exchanged and recharged with AC charging input at 2900W Max, 200-240V-12.5A, 50 / 60HZ.

[0281] Multi-layer application and curing

[0282] The system of the invention supports multi-layer application with controlled gelcure and full cure sequences, improving durability and workflow efficiency. An example is the application of one or more layers of a primer, a base coat and an optional top coat, typically for indoor environments.

[0283] In a specific embodiment the method steps are repeated for the following UV- curable coating layers: i) one to three layers of a UV adhesion primer having a thickness of 0-150 pm in a single pass, the coating layer comprising a concentration of pigment of 0-10 wt %, preferably 0-4 wt %; ii) a UV base coat having a thickness of 0-300 pm in a single pass, the coating layer comprising a concentration of pigment of 3-10 wt %, preferably 5-8 wt %; and iii) an optional UV top coat having a thickness of 0-400 pm, in a single pass, wherein the top coat is a clear coat or comprising a concentration of pigment of 0-10 wt %, preferably 0-3 wt %. In another embodiment the method steps are repeated for the following UV- curable coating layers: a) a UV adhesion primer having a thickness of 0-200 pm in a single pass, the coating layer comprising a concentration of pigment of 0-10 wt %, preferably 0-4 wt %; b) a UV base coat having a thickness of 0-400 pm in a single pass, the coating layer comprising a concentration of pigment of 0-10 wt %, preferably 5-8 wt %; and c) an optional UV top coat having a thickness of 50-250 pm in a single pass, the coating layer comprising a concentration of pigment of 0- 10 wt %, preferably 0-5 wt %.

[0284] In one embodiment of a method of the invention, the primer is not fully cured but gelled; the base coat is not fully cured but gelled if a further top coat is applied onto the base coat; otherwise the base coat is fully cured; and the optional top coat is fully cured.

[0285] In a specific embodiment the method comprises the steps of: a) moving the surface marker along the surface; b) applying a primer comprising 0% by weight pigment, optionally 2-4% by weight; c) applying UV light to the primer and curing the primer, wherein the primer is not fully cured but gelled; d) optionally repeating steps b and c several times for applying multiple layers of primer; e) applying a base coat comprising 3-8% by weight pigment; f) applying UV light to the base coat and curing the base coat, wherein the base coat as top coat is fully cured, or wherein the base coat is not fully cured but gelled if a further top coat is applied onto the base coat; g) applying an optional top coat, wherein the top coat is a clear coat or comprising 3-8% by weight pigment; and h) applying UV light to the optional top coat and curing the top coat fully.

[0286] An example of a method for applying an indoor UV linemarking material in multiple layers comprising a UV primer, a base coat and an optional top coat is set out as follows.

[0287] Applying the UV linemarking primer (clear primer with 0% by weight pigment or optionally containing 2-4% by weight pigments such as TiO2). The primer can be applied by roll but preferably by airless spraying (airless double diaphragm pump pressure at 80-140 bar) a layer onto the surface with a thickness from 50-100 micron. The primer is applied on concrete or difficult surfaces to ensure a good adhesion for the paint. A closed loop system with heated hose ensures a temperature of 25-40 degrees, maintaining a stable viscosity for the UV paint. The primer is not fully cured but lightly gelled to ensure optimal intercoat adhesion for the next layer the linemarking Primer using a separate LED UV light source mobile unit (wavelength, 405 nM only for deep curing) that passes over the applied material at a distance of 30mm. The gelation process is initiated as soon as possible after the application of the UV primer.

[0288] The base coat is applied on a gelled (sticky) primer. This is the higher pigmented layer (containing 4-8% by weight pigments such as TiO2) for good opacity. The base coat can be applied by roll but preferably by airless spraying (airless double diaphragm pump pressure at 80-140 bar) a layer onto the surface with a thickness from 80-200 micron. A closed loop system with heated hose ensures a temperature of 25-40 degrees, maintaining a stable viscosity for the UV paint. The UV linemarking base coat is now fully cured (if this is the last layer, or gelled to ensure optimal intercoat adhesion for the UV top coat layer clear or pigmented) by using a separate LED UV light source mobile unit (wavelength, only 405 nM if aiming for gelation or 405 nM and 365 nm aiming for full cure) that passes over the applied material at a distance of 30 mm. The gelation or curing process is initiated as soon as possible after the application of the UV primer.

[0289] Optionally, when the basecoat is gelled and not fully cured, a UV top coat is applied over base coat. This is an extra layer that makes the system stronger and more durable. The UV top coat is applied on a gelled (sticky) base coat. This is a clear coat (optionally containing 3-8% by weight pigments such as TiO2). The top coat contains waxes to make the line more durable and avoid dirt pick up. Standard they are without pigments, but optionally can contain pigments for good opacity. The UV top coat can be applied by roll but preferably by airless spraying (airless double diaphragm pump pressure at 80-140 bar) a layer onto the surface with a thickness from 80-150 micron. A closed loop system with heated hose ensures a temperature of 25-40 degrees, maintaining a stable viscosity for the UV paint. The UV linemarking top coat is fully cured by using a separate LED UV light source mobile unit (wavelength, 405 nM and 365 nm for deep and top cure) that passes over the applied material at a distance of 30mm. The curing process is initiated as soon as possible after the application of the UV primer.

[0290] Multi-layered single pass coating

[0291] The invention also relates to a method for applying multi-layered coatings in a single pass, steps b and c are repeated with multiple sets of a paint applicator and an LED UV lamp array arranged downstream one another for consecutively applying and curing or gelling an additional coating layer onto the freshly applied and cured or gelled former coating layer.

[0292] In a specific embodiment the invention relates to a method of applying a doublelayered single pass coating with two sets of a paint applicator and an LED UV lamp array, the method comprising the steps of: a) moving a surface marker as disclosed above along a surface and in a single pass: b) applying with a first paint applicator a first UV-curable coating layer up to 250 pm to the surface; c) optionally dropping glass beads or other optically transmissive components onto the surface of the first layer; d) exposing the coating layer to a first LED UV lamp array and curing or gelling the coating layer; e) repeating steps b to d with a second paint applicator and a second LED UV light, whereby the second layer is fully cured.

[0293] In the specific application of primer / base coat / optional top coat, the layers may be applied and cured in separate move along of the surface marker, or alternatively double (or multiple) layers may be applied in a single pass or a single “move along” of the surface marker, for example applying a primer and a base coat in a single pass by means of multiple sets of a paint applicator and an LED UV light.

[0294] In the case of applying different UV paints in a single pass with multiple sets of a paint applicator and LED UV lamp array arranged downstream, the system may comprise multiple paint tanks or split-tanks, for example a double tank for a primer and a base coat paint.

[0295] In a specific embodiment two or more primer, base coat and optional top coat layers are applied in one move along of the surface marker and in a single pass, curing or gelling layer per layer whereby the surface marker comprises multiple sets of a paint applicator and an LED UV lamp array arranged downstream one another.

[0296] Multi-layered primer and top coat

[0297] In yet another specific embodiment of a method of marking an indoor surface steps b and c are repeated several times to apply and gel-cure multiple layers of primer, preferably one to three layers of primer. A top coat is applied and cured using an LED UV light source with a dual wavelength of 405 nM (front zone deep cure) and 365 nm (back zone top cure).

[0298] As such, the present invention discloses a method of marking an indoor surface, comprising 1 to 3 layers of primer sealed with a top coat, the method comprising the steps of: a) moving a surface marker along the surface; b) applying a primer with a clear primer comprising 0% by weight pigment, optionally 2-4% by weight; c) curing the primer using an LED UV light source, wherein the primer is not fully cured but gelled; d) optionally repeating steps b and c several times for applying multiple layers of primer; e) applying a top coat, wherein the top coat is a clear coat comprising 3-8% by weight pigment, and / or the top coat comprises waxes; and f) curing the top coat fully using an LED UV light source with a dual wavelength of 405 nM (front zone deep cure) and 365 nm (back zone top cure). An example of a method for applying an indoor UV linemarking material comprising multiple layers of pigmented primer and a top coat is set out as follows.

[0299] Applying a first coat of UV linemarking primer (containing 2-4% by weight pigments such as TiO2). The primer can be applied by roll but preferably by airless spraying (airless bellow pump with UV resistant packings, pressure at 80-140 bar) 1 layer onto the surface with a thickness from 50-100 micron (first layer preferably as thin as possible for optimal adhesion). The primer is applied ensure a good adhesion and is pigmented to provide more opacity for pigmented UV systems. The closed loop system with heated hose ensures a temperature of 25-40 degrees, maintaining a stable viscosity for the UV paint, approx. The UV linemarking primer is lightly gelled to ensure optimal intercoat adhesion for the next layer using an on board LED UV light source on the airless application unit (wavelength, 405 nM) that passes over the applied material at a distance of 30mm. The gelation process is initiated as soon as possible after the application of the UV primer. The previous steps are repeated at least one more time until the required opacity has been reached.

[0300] The UV top coat (clear or pigmented containing 3-8% by weight pigments such as TiO2) can be applied by roll but preferably by airless spraying (airless bellow pump pressure at 80-140 bar) a layer onto the surface with a thickness from 80-150 micron. A closed loop system with heated hose ensures a temperature of 25-40 degrees, maintaining a stable viscosity for the UV paint. The UV top coat is fully cured using an on board LED UV light source on the airless application unit (wavelength, 405 nM and 365 nm) that passes over the applied material at a distance of 30mm. The gelation process is initiated as soon as possible after the application of the UV primer. The LED UV light source is 25cm (front to 25 back) long and 15cm wide, and uses two wavelengths. LED UV unit consist of an Aluminium housing with a 3 mm quartz glass protective panel, IP67 metal connection panel with LED 405 nm (Front) mixed with 365 nm (back) with narrow beam glass dome LEDs divided into zones every 5 cm each with 95 LEDs per zone, zones can be controlled individually or together via controller, 30 12 VDC 60 mm x 60 mm cooling fan PCB specifications Aluminium PCB, 70 pm copper, white solder resist, black.

[0301] The front zone of the LED UV light source emits a wavelength of 405 nM, length 15cm, (optionally 20cm), strength approx. 3000 mW / cms at 40mm distance (LEDS with narrow beam lenses), LEDs divided into 5 subzones, 5 cm each with 95 LEDs per subzone, subzones 5 can be controlled individually or together. Used to deep cure the UV material applied on the substrate.

[0302] The back zone of the LED UV light source emits a wavelength of 365 nM, length 10cm, (optionally 5, strength approx. 2400 mW / cmz at 40mm distance (LEDS 10 with narrow beam lenses), LEDs divided into 5 subzones, 5 cm each with 95 LEDs per subzone, subzones can be controlled individually or together. Used to deep cure the UV material applied on the substrate.

[0303] In yet another embodiment of a method for marking a surface, only a UV top coat is applied and cured as a protective UV coat over an existing base coat.

[0304] As such, the present invention further discloses a hybrid method of indoor line marking, whereby a UV top coat (clear top coat or with 3%-8% by weight pigments such as TiO2) is applied as a protective UV coat over existing or standard non UV- curable linemarking products. This system is developed to allow more cost effective base coat applications with the benefits of an UV top coating.

[0305] An example of a hybrid method is set out as follows.

[0306] Applying a base coat of standard material for indoor usage, where the compatibility (for adhesion) is certified and tested by the manufacturer of the UV coating. This can be water based, solvent based, 2-component PU, MMA or epoxy systems applied. This can be applied in any thickness, color according to the manufacture’s guideline. Alternatively this can be an odourless 2-component UV based material cured by a peroxide initiator. Wait until is cured (mainly important that all VOCs are out of the system). The UV top coat (clear or pigmented containing 3-8% by weight pigments such as TiO2) can be applied by roll, but preferably by airless spraying (airless bellow pump pressure at 80-140 bar) a layer onto the surface with a thickness from 80-150 micron. A closed loop system with heated hose ensures a temperature of 25-40 degrees, maintaining a stable viscosity for the UV paint. The UV linemarking top coat (clear or pigmented containing 3-8% by weight pigments such as TiO2) is fully cured using an on board LED UV light source on the airless application unit (wavelength, 405 nM and 365 nm) or via a separate UV curing unit that passes over the applied material at a distance of 30mm. The gelation process is initiated as soon as possible after the application of the UV primer.

[0307] The LED UV light source is 25cm (front to back) long and 15cm wide, and uses two wavelengths. LED UV unit consist of an aluminium housing with a 3 mm quartz glass protective panel, IP67 metal connection panel with LED 405 nm (Front) mixed with 365 nm (back) with narrow beam glass dome LEDs divided into zones every 5 cm each with 95 LEDs per zone, zones can be controlled individually or together via controller, 12 VDC 60 mm x 60 mm cooling fan PCB specifications Aluminium PCB, 70 pm copper, white solder resist, black.

[0308] The front zone of the LED UV light source emits a wavelength of 405 nM, length 15cm, (optionally 20cm), strength approx. 3000 mW / cm2at 40mm distance (LEDS with narrow beam lenses), LEDs divided into 5 subzones, 5 cm each with 95 LEDs per subzone, subzones can be controlled individually or together. Used to deep cure the UV material applied on the substrate.

[0309] The back zone of the LED UV light source emits a wavelength of 365 nM, length 10cm, (optionally 5, strength approx. 2400 mW / cm2at 40mm distance (LEDS with narrow beam lenses), LEDs divided into 5 subzones, 5 cm each with 95 LEDs per subzone, subzones can be controlled individually or together. Used to deep cure the UV material applied on the substrate.

[0310] Surface marking and paint composition

[0311] In a third aspect the invention relates to a surface marking for outdoor surfaces applied by a surface marking system or by a method as disclosed above, characterised in that the marking comprises a UV curable coating layer comprising a paint composition adapted for curing by exposure to UV light, the paint composition comprising: a) one or more multifunctional acrylate oligomers in a concentration of 25 to 45% by weight; b) one or more high molecular acrylic binders for enhanced adhesion and flexibility with a molecular weight Mn 10.000- 20.000 Daltons: 1 to 5% by weight; c) one or more multi and / or mono-functional monomers in a concentration of 20 to 45% by weight; d) a main photoinitiator in a concentration of 1 to 5% by weight; and e) one or more alternative or supplementary photoinitiators for different UV light ranges in a concentration of 1 to 5% by weight.

[0312] The paint composition further comprises: a) a polymerization inhibitor or stabilizer for radically curable resins in a concentration of 0,1 to 0,5% by weight; b) one or more polymeric, silicone-free and silicone containing flow and levelling agents for better substrate wetting in a concentration of 0,1 to 1 ,0% by weight; c) one or more defoamers based on organic polymers, silicone free and silicone based to prevent air entrapment in a concentration of 0,1 to 3,0% by weight; d) a hindered amine light stabilizer (HALS) to reduce degradation by sunlight in a concentration of 0,1 to 1 ,5% by weight; e) one or more pigments for color and opacity in a concentration of 0,5 to 5% by weight; f) one or more fillers / extenders for opacity and mechanical properties in a concentration of 15 to 25% by weight; g) one or more adhesion promoters for better adherence to substrates in a concentration of 0,5 to 1 ,5% by weight; and h) one or more rheology modifiers based on hydrophobic pyrogenic silica for optimal flow, leveling and sedimentation in a concentration of 0,1 to 1 ,5% by weight. In one embodiment the paint composition further comprises optically transmissive components.

[0313] In a specific embodiment the surface marking is retroreflective and comprises coated optically transmissive components exposed on the surface of the coating layer.

[0314] In another embodiment the optically transmissive components comprise coated and non-coated components.

[0315] In one embodiment the optically transmissive components are partially coated.

[0316] In a preferred embodiment the optically transmissive components are micro beads, such as glass or quartz beads, and / or angled glass particles.

[0317] In a first specific embodiment of a surface marking according to the invention the coating layer has a thickness between 400 and 500 micron and a concentration of pigment of 0.1 -4% by weight, and comprises drop-on coated optically transmissive components on the surface of the marking. This surface marking is typically a thick outdoor coating for highways.

[0318] In a second specific embodiment of a surface marking according to the invention the coating layer has a thickness between 300 and 400 micron and a concentration of pigment of 4-8% by weight, and optionally comprises drop-on coated optically transmissive components on the surface of the marking. This kind of surface marking is typically a thin outdoor coating for off-highway roads.

[0319] For surface markings comprising coated optically transmissive components on the surface of the marking, the surface of said markings exposes abraded coated optically transmissive components. The coating of the portion of coated optically transmissive components that is exposed on the surface of the marking is abraded by traffic and weather conditions.

[0320] In one embodiment the UV curable coating layer is a top coat applied on an existing base coat.

[0321] In a specific embodiment the surface marking comprises a base coat and a top coat, the base coat comprising any material (dried or cured in any manner), wherein the top coat is UV cured and has a thickness of 80-150 micron, and the top coat optionally comprises coated optically transmissive components, wherein the top coat is a clear coating or a pigmented coating comprising 3-8% by weight pigment.

[0322] In one embodiment the surface marking comprises a primer, a base coat and an optional top coat.

[0323] The primer has a thickness of 0-200 pm and a concentration of pigment of 0-10% by weight, preferably 0-4% by weight. The base coat has a thickness of 0-400 pm and a concentration of pigment of 0-10% by weight, preferably 5-8% by weight. The top coat has a thickness of 50-250 pm and a concentration of pigment of 0- 10% by weight, preferably 0-5% by weight.

[0324] In a specific embodiment, typically for indoor line marking and off-highway applications, the primer has a thickness of 0-150 pm and a concentration of pigment of 0-10% by weight, preferably 0-4% by weight. The base coat has a thickness of 0-300 pm and a concentration of pigment of 3-10% by weight. The top coat has a thickness of 0-400 pm and a concentration of pigment of 0-3% by weight.

[0325] In a specific embodiment the surface marking is a UV cured coating layer comprising one or more layers of primer, a base coat comprising 4-8% by weight pigment and an optional top coat comprising 3-8% by weight pigment. In one embodiment the primer is a clear primer comprising 0% by weight pigment or comprising 2-4% by weight pigment quartz beads, and / or angled glass particles.

[0326] In a specific embodiment the surface marking for outdoor or off-highway or indoor surfaces, comprises an existing base coat and a top coat, the base coat comprising any material (dried or cured in any manner), wherein the top coat is UV cured and has a thickness of 80-150 micron, wherein the top coat is a clear coating or a pigmented coating comprising 3-8% by weight pigment.

[0327] With the intention of better showing the characteristics of the invention, some embodiments according to the invention are described, by way of an example without any limiting nature, with reference to the accompanying drawings, wherein: figure 1 represents an embodiment of a frame for an electric driven mobile unit according to the invention; figure 2 represents an embodiment of a frame of a mobile unit according to the invention comprising a frame integrated power pack and a LED UV light source with height adjustment; figure 3 represents an embodiment of a mobile unit according to the invention further comprising a unit having an electric bellow pump, a heated tank and a flow meter, and a laser indicator; figure 4 represents an embodiment of a mobile unit according to the invention comprising a unit having an air-powered pump, a heated tank and a flow meter ; figure 5 represents an embodiment of a mobile unit according to the invention comprising a unit having a compressor (more than 200l / m); figure 6 represents an embodiment of a UV blocking shroud according to the invention; figure 7 represents an embodiment of an overspray suction system according to the invention; figure 8 represents an embodiment of a height adjustment system according to the invention; figure 9 represents an embodiment of a heated tank for storing UV paint according to the invention; figure 10 represents a first embodiment of a LED UV light source according to the invention; figure 11 represents a second embodiment of a LED UV light source according to the invention; figure 12 represents a third embodiment of a LED UV light source according to the invention; and figure 13 represents an embodiment of the UV curing process.

[0328] Figure 1 represents an embodiment of a frame 5 for an electric driven 2 mobile unit 1 according to the invention. The frame has two wheels powered by the power supply 3 (not shown) of the marking system. The frame has a handle bar for guidance by an operator.

[0329] The frame could also have remote controlled guidance and steering. The adjustment system for height, line width, flow meter, etc. could also be controlled remotely and automatically. In this way the mobile unit operator does not need to be close to the mobile unit and high-intensity UV light sources.

[0330] Figure 2 further represents the mobile unit of figure 1 with a power pack 3 integrated in / on the bottom of the frame and a LED UV light source 4 held at the side of the frame mounted by holding means 16. The frame also houses an electric height adjustment system 14 for adjusting the height of the LED UV light source 4.

[0331] The LED UV light source 4 has a front working section 4A and a back working section 4B. The front / back working sections are related to the driving direction of the mobile unit indicated by the arrow. Figure 3 further represents the mobile unit of figures 1 and 2 wherein the frame further houses an electric bellow pump 11 , a heated tank 7, a manual (airless) pistol spray gun 6 with a heated hose, a flow meter 12 and a laser indicator 15.

[0332] The frame further houses a second electric height adjustment system 14 for adjusting the height of the spray gun 6 and the laser indicator 15.

[0333] Placement of the components on the frame can differ in alternative mobile units depending on the specific use, power and size of the unit.

[0334] Figures 4 further represents the mobile unit of figure 3 with a compressor 10. The LED UV light source 4 and a height adjustment system is not shown in figure 4.

[0335] Figure 5 represents another embodiment of a mobile unit 1 according to the invention further comprising a glass bead dispenser (pistol) 9 for applying coated optically transmissive components based on gravity or by pressure. The compressor 10 has a rate of more than 200 l / min. The pump 11 is an airless double membrane or bellow pump powered by an air engine. The LED UV light source 4 is not shown in figure 5.

[0336] This type of mobile unit is a larger unit and typically applies to outdoor applications.

[0337] Figure 6 represents a preferred embodiment of a UV protective shroud 19. The shroud has a top panel 20 in transparent UV filtering / blocking material, two side panels 21 and a front and back panel 22. The panels surround the LED UV light source 4. Other similar configurations for a UV protective shroud surrounding the LED UV light source are possible, as long as the UV light spread out in any direction of the LED UV light source is optimally blocked or filtered from an operator or bystander. Figure 7 represents a mobile unit 1 further comprising an overspray suction system 24 mounted as a hood over the spray gun and spray nozzle 6 (not shown). The overspray suction system 24 is fixed to the frame. The suction system comprises an exhaust and a replaceable filter system to capture the overspray particles.

[0338] Figure 8 represents a detail of an adjustable height adjustment system 14. The main guiding arm 17 / 18 towards the laser indicator 15 and the spray gun 6 (not shown) is adjustable in height.

[0339] Figure 9 represents an embodiment of a heated tank 7 for storing UV paint according to the invention. The tank 7 mainly has the shape of a round reservoir 7a with a hopper shape 7b at the bottom, where the tank connects to a pump via outlet 7c. The connection may comprise an optional valve to open or close the tank for allowing the hopper to be dismounted easily. The tank 7a / 7b is doublesided.

[0340] Figures 10 and 11 represent a LED UV light source comprising multiple sections. The sections are comprised in one light source housing 4 and are divided either according to the front / back (fig. 10) or the left / right (fig. 11 ) sections of the light source.

[0341] Figure 10 represents a first embodiment of a LED UV light source according to the invention. The LED UV light source (housing) is a uniform flood light, and is divided into two different irradiance sections. Alternatively the LED UV light source (housing) can be divided in more than two irradiance sections. This setup avoids separate housings, but mainly it avoids potential gaps in between the flood light and the focus light. This set up further allows bigger light sources, providing a longer dwell time, at higher speeds, but allows energy savings on mobile units that have limited energy supply. The first irradiance section 23a is a flood LED UV light source with a uniform intensity typically between 2000 mW / cm2up to 5000 mW / cm2. This irradiance section 23a is typically configured at the back of the light source 1 .

[0342] The second irradiance section 23b at the front of the light source 1 is a higher- intensity LED UV light source with an intensity typically between 4000 mW / cm2up to 16000 mW / cm2.

[0343] The sections can be organized by different PLC’s, switches, energy supply, etc. Alternatively, the stronger irradiance section can also be in front of the LED UV light source housing.

[0344] Figure 11 represents a second embodiment of a LED UV light source according to the invention. Figure 11 represents a flood LED UV light with three uniform LED UV sections. The two energy saving sections 23a at the lengthwise side parts of the LED UV light source can be separately switched on or off to save energy. The three sections have an identical irradiance and wavelength in this example.

[0345] As an example the total width of the LED UV light source is 30cm. Section 23b has a width of 20 cm, section 23a is 5 cm wide per section. Via the controller section 23a can be switched off (individually or both) to save energy. If both sections 23a are switched off, the width of the light source that is working is now 20cm (section 23b). This allows the operator to easily cure 15cm lines, while doing significant energy savings. Should the operator encounter a 20cm line, he can switch on one or both sections 23a and cure the line.

[0346] Figure 12 represents a third embodiment of a LED UV light source according to the invention. Figure 12 represents a LED UV light source comprising different irradiance and wavelength sections.

[0347] The light source (housing) 1 comprises a LED UV flood light with different sections. As per example the total length of the light source is 500mm long and 300 mm wide. The first irradiance section 23a near the front of the light source is a LED UV light source 405 nM wavelength with a higher intensity typically between 4000 mW / cm2. The second irradiance section 23b is a LED UV light source 405 nm wavelength with a lower intensity typically between 2000 mW / cm2up to 5000 mW / cm2. The third irradiance section 23c near the back of the LED UV light source is a LED UV light source 365 nm wavelength with an intensity typically between 2000 mW / cm2up to 3000 mW / cm2.

[0348] Figure 13 represents an embodiment of a UV application and curing process of spraying a layer of UV paint with a spray gun 6, using a laser-guided line width indicator 15 for enhancing the precision and reliability of the application process, dispensing coated optically transmissive components with a bead dispenser 9 on the freshly applied wet UV paint and curing the coating layer with the drop-on beads with a LED UV light source 4.

Claims

Claims1 . A surface marking system (1 ) for the application and UV curing of a surface marking, the system comprising a paint applicator (6), an LED UV lamp array (4) and a power supply (3), whereby the system is movable over a road or surface, and the system is configured such that as it moves, the paint applicator (6) applies a coating layer of UV paint on a road or surface, and the LED UV lamp array (4) cures the coating layer, characterised in that the system comprises: a. at least one paint applicator (6) arranged to dispense a UV-curable coating on a surface, b. at least one LED UV lamp array (4) arranged downstream of a paint applicator and configured to: i. emit radiation having a peak wavelength in the range 365-495 nm, preferably 365-405 nm; ii. provide a peak irradiance of at least 2500 mW / cm2at the coating surface, and iii. deliver an energy dose of at least 2500 mJ / cm2in a single pass; c. an air-cooling assembly configured to maintain an LED-junction temperature of at most 100 °C, preferably 90 °C, during continuous operation at the irradiance specified in feature (b); d. an on-board rechargeable power pack, comprising one or more battery modules, capable of supplying at least 3600 W continuous electrical power and at least 18 kW peak electrical power; wherein the system is operable to cure in a single pass, in ambient air and without the use of glass beads or other optically-transmissive fillers, a UV- curable coating having a dry-film thickness of up to 500 pm at a travel speed of at least 1 km / h.

2. The system according to claim 1 , characterised in that the system is operable to cure a UV-curable coating having a dry-film thickness of up to 400 pm and a concentration of pigment of 2-10 wt %, preferably 2-8 wt %.

3. The system according to claim 1 , characterised in that the system is operable to cure UV-curable coating having a dry-film thickness of up to 500 pm and a concentration of pigment of 0.1-4 wt %, preferably 0.1-2 wt %.

4. The system according to claim 1 or 2, characterised in that the system is operable to cure a UV-curable coating having a dry-film thickness of up to 400 pm and a concentration of titanium dioxide pigment not exceeding 2.5 wt %.

5. The system according to claim 1 or 3, characterised in that the system is operable to cure a UV-curable coating having a dry-film thickness of up to 500 pm and a concentration of titanium dioxide pigment not exceeding 1 wt %.

6. The system according to claim 1 , characterised in that the system is self- propelled and comprises a traction drive powered by the power pack.

7. The system according to claim 1 , characterised in that the power pack provides at least 4 kW continuous electrical power.

8. The system according to claim 1 , characterised in that the LED UV lamp array (4) comprises a first section that emits radiation having a peak wavelength of 405 nm at an irradiance of 5000-8000 mW / cm, and a second section, located downstream of the first section, that emits radiation having a peak wavelength of 365 nm at an irradiance of 2500-4000 mW / cm.

9. The system according to claim 1 or 8, characterised in that the LED UV lamp array (4) is divided into transverse modules that are independently switchable in increments of not more than 25 mm to match a selected line width.

10. The system according to any of the preceding claims, characterised in that the least one LED UV lamp array (4) provides a peak irradiance of at least 3500 mW / cm2at the coating surface, and delivers an energy dose of at least 5000 mJ / cm2in a single pass; and the on-board power pack is a hybrid power pack comprising one or more rechargeable battery modules and optionally an auxiliary generator, wherein the power pack is capable of supplying at least 4000 W continuous electrical power and at least 18 kW peak electrical power, wherein the system is operable to cure in ambient air, in a single pass and without the use of glass beads or other optically- transmissive fillers for effective curing, a UV-curable coating having a dryfilm thickness up to 500 pm at a travel speed of at least 2 km / h.

11. The system according to claim 10, characterised in that the system is operable to cure UV-curable coating having a concentration of pigment not exceeding 3-8 wt %.

12. The system according to claim 10, characterised in that the system comprises a drop-on dispenser positioned adjacent the paint applicator for dropping glass beads or other retro-reflective particles onto the surface of a freshly applied coating layer before UV curing.

13. The system according to claim 12, characterised in that a controller synchronizes the dispenser with a switch-on of the LED UV lamp array (4) so that the glass beads or other retro-reflective particles are at least partly embedded in the coating before curing.

14. The system according to claim 10, characterised in that the system is a ride-on or truck-mounted road marking system comprising a traction drive powered by the hybrid power pack.

15. The system according to claim 10, characterised in that the hybrid power pack supplies at least 8 kW continuous electrical power.

16. The system according to claim 10, characterised in that the auxiliary generator recharges the battery modules during transit between marking sites.

17. The system according to claim 10, characterised in that the LED UV lamp array (4) comprises a first section that emits radiation having a peak wavelength of 405 nm at an irradiance of 6000-10000 mW / cm and a second section, located downstream of the first section, that emits radiation having a peak wavelength of 365 nm at an irradiance of 3500-5000 mW / cm.

18. The system according to claim 1 or 17, characterised in that the LED UV lamp array is divided into transverse modules that are independently switchable in 50 mm increments to match a selected line width.

19. The system according to any of the preceding claims, characterised in that the LED UV lamp array (4) modules are dimmable over a range of 0-100 % of maximum output.

20. The system according to any of the preceding claims, characterised in that the LED UV lamp array comprises a UV floodlamp with an intensity of 2000- 6000mW / cm2, preferably 2500-4000mW / cm2, and a more focused UV lamp array with a high-intensity of 5000-16000m W / cm2.

21. The system according to any of the preceding claims, characterised in that the on-board power pack is exchangeable.

22. The system according to any of the preceding claims, characterised in that it comprises a UV-blocking shield positioned 5-40 mm above the marking surface so as to block at least 99 % of stray ultraviolet radiation.

23. The system according to any of the preceding claims, characterised in that it comprises a closed-loop heated hose and an optional insulated paint tank that maintain the temperature of the UV-curable coating between 25 °C and 40 °C.

24. The system according to any of the preceding claims, characterised in that an electronic controller governs the traction-drive speed so that the travel speed varies by no more than ±5 % of a set value during curing.

25. The system according to any of the preceding claims, characterised in that a flow-meter and feedback controller maintain a constant volumetric flow rate of the UV-curable coating during application.

26. The system according to any of the preceding claims, characterised in that an electronic controller monitors coating flow rate, travel speed and LED UV lamp array output and adjusts the parameters in real time to maintain a target energy dose per unit length.

27. The surface marking system according to any of the preceding claims, whereby the system comprises an overspray suction system (24) configured as a spray booth surrounding the spray gun and nozzle, and equipped with suction mechanisms to capture overspray particles during paint application.

28. The system according to any of the preceding claims, characterised in that the pigment is titanium-dioxide.

29. The system according to any of the preceding claims, characterised in that the air-cooling assembly comprises at least one forced-air device providing a combined volumetric flow of at least 200 m3 / h across a finned heat-sink having a height of 70-95 mm and a planform area of at least 40 000 mm2.

30. The system according to claim 29, characterised in that the LEDs are mounted to an IMS PCB with in-plane thermal conductivity of at least 10 W m-1K"1, coupled to the heat-sink by a TIM layer of 0.3-0.7 mm thickness and thermal conductivity of at least 5 W m-1K"1.

31. The system according to any of claims 29 or 30, characterised in that a lamp housing defines inlet / outlet apertures of 50-65 mm and internal guide rails or baffles of 3-5 mm that duct airflow across the LED board and fins.

32. The system according to any of claims 29 to 31 , characterised in that the LED UV lamp electrical input during operation is 0.6-1 .2 kW.

33. The system according to any of the preceding claims, characterised in that the system further comprises a closed liquid loop including a pump, heat exchanger and coolant channels in thermal contact with the LED UV lamp array.

34. The system according to any of the preceding claims, characterised in that the system comprises multiple sets of a paint applicator (6) and an LED UV lamp array (4) arranged downstream one another for consecutively applying and curing multiple coating layers in a single pass.

35. The system according to claim 34, characterised in that the system comprises a first paint applicator (6a) and a first LED UV lamp array (4a)configured for applying and curing a first coating layer, and a second paint applicator (6b) and a second LED UV lamp array (4a) arranged downstream of the first, and configured for immediately applying and curing a second coating layer onto the cured first coating layer.

36. The system according to claim 34 or 35, characterised in that the system comprises multiple paint tanks or a split-tank for different UV-curable paints.

37. The system according to any of claims 34 to 36, characterised in that the system is operable to cure UV-curable coating having 5-13% of pigment content and having a total coating thickness of 250 up to 400-500 pm.

38. The system according to any of claims 34 to 37, characterised in that the individual layers have a thickness below 250 pm.

39. A method of marking a surface with a surface marking system according to any of the preceding claims, the method comprising the steps of: a. moving a surface marker along the surface at a travel speed of at least 1 km / h and in a single pass: b. applying with the paint applicator a UV-curable coating layer up to 500 pm to the surface; and c. exposing the coating to the LED UV lamp array and curing or gelling the coating.

40. The method according to claim 39, wherein the coating layer is fully cured and hardened within 60 seconds of application.41 . The method according to claim 39 or 40, wherein step b is followed by the step of dispensing drop-on glass beads or optically transmissive components onto the surface of the final coating layer before curing.

42. The method according to any of claims 39 to 41 , wherein the method steps are repeated for the following UV-curable coating layers: i. One to three layers of a UV adhesion primer having a thickness of 0- 150 pm in a single pass, the coating layer comprising a concentration of pigment of 0-10 wt %, preferably 0-4 wt %; ii. a UV base coat having a thickness of 0-300 pm in a single pass, the coating layer comprising a concentration of pigment of 3-10 wt %, preferably 5-8 wt %; iii. an optional UV top coat having a thickness of 0-400 pm, in a single pass, wherein the top coat is a clear coat or comprising a concentration of pigment of 0-10 wt %, preferably 0-3 wt %.

43. The method according to claim 42, wherein i. the primer is not fully cured but gelled; ii. the base coat is not fully cured but gelled if a further top coat is applied onto the base coat; otherwise the base coat is fully cured; iii. the optional top coat is fully cured.

44. The method according to any of claims 39 to 43, for applying multi-layered coatings in a single pass wherein steps b and c are repeated with multiple sets of a paint applicator and an LED UV lamp array arranged downstream one another for consecutively applying and curing / gelling an additional coating layer onto the freshly applied and cured former coating layer.

45. The method according to claim 44, for applying a double-layered single pass coating with two sets of a paint applicator and an LED UV lamp array, the method comprising the steps of: a) moving a surface marker along a surface and in a single pass: b) applying with a first paint applicator a first UV-curable coating layer up to 250 pm to the surface; c) optionally dropping glass beads or other optically transmissive components onto the surface of the first layer;d) exposing the coating layer to a first LED UV lamp array and curing or gelling the coating layer; e) repeating steps b to d with a second paint applicator and a second LED UV light, whereby the second layer is fully cured.

46. The method according to any of claims 42 to 45, wherein two or more of the primer, base coat and optional top coat layers are applied in one move along of the surface marker and in a single pass, curing or gelling layer per layer whereby the surface marker comprises multiple sets of a paint applicator and an LED UV lamp array arranged downstream one another.

47. The method according to any of claims 39 to 46, wherein a UV top coat is applied and cured as a protective UV coat over an existing base coat.

48. A lamp module for a surface marking system of any of claims 1 to 38, the lamp module comprising an LED UV array, an air-cooling assembly including a finned heat-sink and a ducted airflow path formed by a lamp housing, and an IMS PCB and TIM disposed between the array and the heat-sink, the module configured such that the LED junction temperature does not exceed 90 °C during continuous operation at a peak irradiance of at least 2500 mW / cm249. The system according to any of claims 1 to 38, characterised in that the system is operable to cure a UV-curable coating having a dry-film thickness of up to 300 pm and a concentration of pigment of 3-10 wt %, and a dry-film thickness of up to 500 pm and a concentration of pigment of 0-3 wt %.

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