Quels sont les processus d'étanchéité utilisés dans les socs de LED ?

In outdoor landscape lighting, LED strip lights are highly favored for their flexibility and decorative appeal. However, traditional LED strip lights are often susceptible to water damage in outdoor environments, leading to diminished lighting performance or even damage. Waterproof LED strip lights effectively address this issue. Waterproof LED light strips not only offer superior waterproof performance but also maintain stable lighting under various harsh weather conditions without compromising their decorative effects.

However, there are various types of waterproof LED strip lights, and many people may not be well-informed about them. When selecting them, one should consider their price and evaluate their waterproof performance, the intended usage environment, safety, and lighting color, among other factors. Below, I will provide a detailed introduction to the relevant waterproofing techniques for LED strip lights.

What are the waterproofing processes for COB and SMD LED strips?

Currently, the main waterproofing processes for COB and SMD LED strips include spray coating, drip coating, tubing, potting, extrusion, and coating. Each of these processes has its own characteristics. Let’s take a look at the differences between them:

Spray Coating Process

The spray adhesive process primarily uses a spray adhesive machine to apply silicone adhesive to the surface of the light strip. The thickness of the adhesive layer is generally quite thin, typically around 30-50 microns. Due to the thinness of the adhesive layer, it has minimal impact on the original optical performance of the light strip, such as brightness, color temperature, and color rendering index.

Spray-coated LED strips are LED lighting products that combine adhesive bonding technology. This gel provides splash-proof protection, enabling the spray-coated LED strip products to achieve an IP54 or higher protection rating, thereby enhancing the LED strip’s waterproof, dustproof, and high-temperature resistance performance. These LED strips are typically installed in bathrooms, kitchens, outdoor areas, or splash-proof environments. They are suitable for both dry and humid environments, such as living rooms, kitchens, and bathrooms. They are not recommended for use in areas prone to water splashes.

Drop-glue Process

The drop-glue process involves first securing the light strip in a straight line and then using a high-precision dispensing machine to move along the PCB path of the light strip, injecting epoxy resin or PU adhesive onto the surface of the light strip. By controlling the adhesive output from the nozzle, the adhesive layer is uniformly applied to cover the light-emitting components and circuitry.

The thickness of the droplets is generally controlled around 2mm. LED light strips produced using the drop-coating process achieve an IP67 or higher protection rating while maintaining flexibility and heat dissipation performance. This process is suitable for humid environments, effectively providing surface waterproofing, and can be used in various settings such as hotels, homes, and offices.

The advantages of drop glue LED strips include simple operation and lower costs, but the protection rating is limited (typically IP54-IP65). Disadvantages include potential impact on heat dissipation, as well as some effects on color temperature and brightness, and the tendency to yellow over time with prolonged outdoor use.

Hollow Sleeve Process

The sleeve LED strip process is relatively simple, primarily involving inserting the entire LED strip into a silicone/PVC tube and then sealing both ends to prevent water ingress from rain or other sources. This process enables the LED strip to achieve a waterproof rating of approximately IP66.

The advantages of sleeve LED light strips include good flexibility, suitability for curved installations, and effective water resistance. However, a drawback is that LED light strips with sleeves are only suitable for regions with higher temperatures in the south. In colder northern regions, the LEDs inside the sleeves may generate heat during operation. When the external environment is cold, the air and water inside the sleeves may oxidize, potentially corroding the LEDs or oxidizing the circuit board. The manufacturing cost of tubular LED light strips is relatively high, and their heat dissipation performance is slightly inferior, which may affect their lifespan when used continuously for extended periods.

Please watch the following video to learn how to make a hollow sleeve LED strip.

Sleeve Filling Process

The LED strip sleeve filling process involves slipping a transparent PVC or silicone sleeve over the LED strip surface, then mixing two-component organic silicone or epoxy resin in the correct ratio to eliminate bubbles (to prevent air pockets after curing). An automatic encapsulation machine then uniformly injects the encapsulation material into the sleeve along the length of the strip. After curing, a sealed layer forms inside the sleeve, effectively enhancing waterproofing and mechanical performance.

After filling, the LED strip achieves an IP68 waterproof rating, enabling use in outdoor or harsh environments. Potted LED strips, with their sealing properties, weather resistance, and chemical stability, are widely applicable in demanding scenarios such as outdoor lighting, industrial illumination, and vehicle decoration, making them an ideal choice for long-term, maintenance-free lighting solutions.

Extrusion Process

The extrusion process for flexible LED strips involves heating and melting thermoplastic materials (such as PVC or silicone), then using a screw extruder to force the material into a precision mold, continuously extruding it into a strip-like structure. LED chips and wires are simultaneously embedded, and a protective layer is applied using co-extrusion technology. After cooling and forming, the strip is wound onto a core. This process ensures the flexibility, waterproofing, and uniform light emission of the light strips, making them suitable for curved decorative lighting. It also offers high production efficiency and customizable colors and sizes.

The waterproof rating of extruded light strips can reach IP68, thanks to their one-piece waterproof structure (using an extrusion process that wraps the light core with silicone) and excellent weather resistance and installation flexibility. They are widely used in various scenarios, particularly suitable for applications requiring waterproofing, durability, or complex environmental lighting.

PECVD Nano-Coating Process

The coating process for LED strips primarily uses PECVD nano-coating waterproof coating technology, which forms an ultra-thin and dense nano-level waterproof coating on the surface of LED fixtures through plasma-enhanced chemical vapor deposition. The coating thickness can range from 1 to 100 μm. When the coating thickness is sufficient, it achieves all-around waterproofing and moisture resistance (IP68 rating) without affecting LED chip heat dissipation.

The nano-coating on the LED strip is colorless and transparent, so it doesn’t affect light transmission, ensuring the product’s lighting and visual effects. The coating thickness is controllable, with PECVD coating thicknesses ranging from 1 to 100 μm. While meeting waterproofing requirements, the coating thickness can be as thin as 0.1 μm, so it doesn’t affect the heat dissipation of the LED chips.

Selection of Waterproof LED Strip Lights

When selecting waterproof LED strip lights, the following key factors should be considered based on current mainstream application requirements:

1. Selection based on waterproof rating

• ‌IP54 Surface-Spray LED Strip Lights: These lights feature a surface-applied adhesive layer, providing splash resistance but not immersion resistance. They are suitable for lightly humid environments such as kitchen cabinets and dry areas in bathrooms.

• IP65 Drop-Coated LED Strip Lights: Effectively provide surface waterproofing, suitable for various settings such as hotels, homes, and offices.

• IP66 Hollow Silicone Sleeve Waterproof LED Strips: Achieve spray resistance through hollow silicone tubes, suitable for semi-outdoor settings like balconies and courtyards, but may leak if submerged for extended periods.

• IP67/IP68 Solid Silicone Filling LED strips (including sleeve potting and solid extrusion): Using a fully enclosed solid silicone process, these can be directly submerged for use (e.g., in fish tanks or pools). They are flexible and can be freely bent into shapes. They use a low-voltage 24V design to avoid the risk of electric shock.

• IP65-IP68 Nano-Coated LED Strips: The waterproof performance of this process is flexible, allowing the coating thickness to be customized based on waterproofing requirements. For example, in an IP65 environment, the coating thickness can be 0.1-0.3 microns; in an IP68 environment, the coating thickness must be 1-2 microns.

For more information on IP ratings, please read the blog: Guide d'étanchéité des bandes lumineuses à LED (indice IP).

2. Matching based on usage scenarios

• Underwater/extremely humid environments: IP68 silicone solid LED strips are mandatory, such as for pool walls or aquarium lighting.

• Outdoor buildings/canopies: LED strips with IP65 or higher are recommended, requiring professional installation to prevent electric shock.

• Bathroom mirror cabinets/cabinet bottoms: IP65 low-voltage potted LED strips are safer, moisture-resistant, and emit soft light.

• ‌Tunnels/construction lighting‌: High-brightness waterproof light strips with encapsulated or coated options are preferred and must be used with protective enclosures.

3. Voltage safety‌

• 24V low-voltage light strips must be used in areas where human contact is likely (e.g., baseboards, furniture shelves);

• High-voltage light strips must only be installed by professionals in high or concealed locations.

4. Luminous efficacy and quality‌

• If a color rendering index (CRI) of ≥90Ra (preferably ≥95Ra) is required to ensure color accuracy, COB waterproof light strips should be prioritized.

• If high light consistency is required, Bandes lumineuses LED with over 120 LEDs per meter or COB light strips with over 320 LEDs per meter should be selected to avoid a grainy appearance.

• If high color temperature accuracy and temperature control are required, choose spray-coated or coated LED strips. These types of LED strips have a thinner coating, so the color temperature does not drift, and they have better heat dissipation performance.

5. Voltage drop control

• 24V LED strips should be ≤20 meters per strip, and 12V LED strips should be ≤5 meters per strip. For longer lengths, a parallel power supply is required to prevent dimming at the ends.

6. Installation and maintenance tips

• Transformer Hiding: Plan power supply locations in advance (e.g., air conditioner maintenance openings, recessed light holes);

• Cutting Flexibility: Prefer models where each LED can be cut to achieve precise dimensions.

• Material Durability: Silicone material has better aging resistance than PVC tubing, extending outdoor lifespan by over 30%.

Résumé: First confirm waterproofing requirements (IP rating) → Match scene voltage → Check light efficiency parameters (CRI/LED count/color temperature) → Plan the installation scheme (transformer location + voltage drop handling). Example: For bathroom mirror cabinets, choose a 24V IP68 silicone LED strip (3000K, 120 LEDs/meter) paired with a hidden transformer installed within the ceiling.

The Impact of Different Processes on Color Temperature in Waterproof LED Strips

Those familiar with waterproof LED strips know that the addition of different materials, such as silicone, PVC, and PU adhesive, causes color shifts when light passes through these materials. Therefore, different manufacturing processes result in varying changes in color temperature. As shown in the table below, this is a summary of color temperature corresponding to different manufacturing processes compiled by Sainai Optoelectronics based on years of experience in producing waterproof LED strips, for reference:

Referring to the above table, when designing LED strips, we must adjust the color temperature accordingly based on the changes caused by the waterproofing process. For example, if you need a waterproof silicone-coated COB LED strip with a color temperature of 3000K, selecting a 3000K color temperature LED strip for silicone coating is incorrect, as the resulting color temperature will be around 3300K. Instead, you should choose a COB LED strip with a color temperature of 2700K for silicone coating, as the color temperature will increase by 10% after the process, resulting in the desired 3000K color temperature for the final product.

Test data on the impact of waterproofing processes on color temperature: Please refer to the author’s other article: Quels sont les types de bandes LED ?

Cost Comparison of Different Processes for Waterproof LED Strips

Among waterproof LED strips, the spray coating process has the lowest cost, with simple equipment suitable for small-area precision coating; the drip coating process has moderate equipment costs but high production efficiency, suitable for medium-volume production; and the injection molding and extrusion processes require the highest equipment investment but achieve 95% material utilization and a 3-5 times increase in production efficiency, suitable for continuous large-scale production. The coating process has the highest overall cost, with equipment costing 1-3 million yuan, requiring a vacuum environment, and high energy consumption. However, it can achieve nanoscale thin films, and the cost per unit decreases significantly with increased production volume.

Résumé

In summary, the selection of production processes for waterproof LED strips should consider the usage environment (humidity, temperature), protection rating, heat dissipation requirements, and cost budget.

If waterproofing requirements are not stringent, the spray process can be chosen for its cost-effectiveness; if waterproofing requirements are high, the extrusion process can be selected, though it is more expensive. If color temperature and heat dissipation requirements are high, the nano-coating process is recommended. Nano-coating waterproof coating technology offers innovative solutions to waterproofing and heat dissipation challenges for LED strip lighting fixtures with its unique advantages.

With ongoing technological advancements and further cost reductions, the future holds promising prospects for LED strip lighting waterproofing and heat dissipation technology, driven by the emergence of new materials and processes.