Enhanced protection for enhanced PCB performance
Conformal coatings are designed to protect printed circuit boards and related equipment from their environment. Typically applied at 25-75μm, these coatings ‘conform’ to the contours of the board allowing for excellent protection and coverage, ultimately extending the working life of the PCB.More info > Download product selector chart > Download product brochure >
The use of conformal coatings is particularly important in automotive, military, aerospace, marine, lighting, industrial and green energy applications. Due to the rapid expansion of the electronics industry, conformal coatings are also finding their way into the domestic and mobile electronics industries, providing the necessary combination of high performance and reliability within a vast array of electronic devices.
Conformal coatings can be used in a wide range of environments to protect printed circuit boards from moisture, salt spray, chemicals and temperature extremes in order to prevent corrosion, mould growth and electrical failures, for example. The protection provided by conformal coatings allows for higher power and closer track spacing, in turn enabling designers to meet the demands of miniaturisation and reliability.
Electrolube is among the world’s foremost experts in the formulation and application of conformal coatings designed to meet international approvals (including European and American military specifications). The range of products currently available comprises acrylics, silicones, polyurethanes, hybrid chemistries and environmentally friendly options.
Electrolube can offer both transparent and pigmented coatings to improve or camouflage the appearance of printed circuit boards. The range also includes a number of ancillary products to complement the use of our conformal coatings, including thinners and removers, peelable coating masks and thixotropic materials for dam and fill applications.
Coatings can be categorised by their base chemistry, each option having its own beneficial properties for the different environments the PCB will be operating in. The most widely used materials are historically solvent-based, the benefits of which include:
Acrylics combine reasonable price with good environmental protection; they retain clarity and can resist darkening and hydrolysis during extended exterior exposure. They do however have a limited solvent resistance, making them suitable for re-work but not applications where chemical resistance is important.
In contrast to acrylics, polyurethane coatings offer excellent chemical resistance and superior protection in harsh environments. They also maintain flexibility at very low temperatures. Like acrylics, they are also very versatile covering a broad operating temperature range.
Hybrid coatings are where a mixture of base chemistries are used. These can result in a number of different coating options, tailoring the requirements for specific applications.
Electrolube’s SCC3 range of conformal coatings are polyurethane base resins modified with silicone to enhance the high temperature properties of the resin. These coatings display a wide range of advantages over standard materials and as they are solvent-based, they also provide all the benefits of ease of application. The SCC3 range of coatings offers a wide range of performance benefits without the problems associated with standard silicone coatings; i.e. silicone migration and the effects of low molecular weight siloxanes.
Electrolube also provide other modified silicone technologies which have been specifically designed for the railway industry. These coatings offer a wide range of protection in a both challenging and rapidly changing environments.
Electrolube offer a range of hybrid coatings, including low-VOC and non-VOC options.
Water based coatings cure by evaporation of water from the system. They are low-VOC options, replacing the majority of solvent in the system with water. This improves operator safety and also dramatically reduces solvent emissions.
UV cure conformal coatings are also another example of hybrid coatings. In this case, different chemistry types are often used to produce a dual-cure system, thus avoiding issues with areas shadowed from the UV light during curing. UV cure coatings offer the fastest curing times with coatings curing in seconds under UV light. This is extremely beneficial for high throughput applications and any shadowed areas will cure via the secondary cure system over time. Due to their highly cross-linked structure when cured, they can be difficult to remove and in some cases UV cure coatings are known to suffer from reduced flexibility during thermal changes and therefore must be carefully tested.