The Future is Bright for UV/Dual Cure Silicone Sealants

The market continues to evolve as customers embrace the many benefits of UV/dual cure silicone sealants in their applications.

The future is bright for UV dual cure sealantsUV cured conformal coatings have been used in recent years to seal and protect sensitive electronics applications. UV curing has offered a number of advantages: faster curing times, elimination of hazardous solvents, lower processing costs due to quicker cycles, and a reduction in dedicated floor space. But there were drawbacks too – a lack of adhesion chemistry and UV coatings didn’t always cure at the same rate in shadowed or raised spots on a Printed Circuit Board (PCB).

We solved that issue in 2019 when we introduced the first commercially available electronics grade UV/dual cure silicone conformal coating. Our R&D lab combined a UV primary cure that cures tack free in seconds with a secondary alkoxy moisture cure that eliminates unreacted coating in shadow areas.

Novagard’s 800-505 UV/Dual Cure Silicone Conformal Coating was just the beginning of innovation in this space. We have been working with our customers and partners to develop additional products that fit their unique specifications and applications. “We are proud of the family of UV/dual cure silicone sealants that we are bringing to the market,” states an enthusiastic Jason Clark, Vice President of Electronics and EV at Novagard. “This product line continues to grow as our R&D lab offers advanced solutions targeted at solving specific challenges.”

Sprayable/Flowable Products

Sprayable/Flowable ProductsNovagard’s line of low viscosity sprayable/flowable UV/dual cure silicone products are used when a thin coating is desirable. UV coatings act as dielectric insulation – a barrier against environmental contaminants such as moisture, dirt, dust, and humidity. They offer a protective layer against abrasions & solvents, and dampen stress causing vibrations of critical components.

This class of product is primarily used for conformal coating of circuit boards, electronic components, and devices. Conformal coatings help prolong the life of a product, and are used across many markets, including electronics, automotive & transportation, military, industrial, lighting, medical electronics, and wearables.

UV/dual cure silicone sprayable products are 100% silicone, chemically stable, operate in a wide temperature range, are resistant to ozone and UV degradation, and provide superior moisture protection.

Viscosity is key to the sprayable class – the lower the viscosity (as measured in centipoises or cPs), the easier to spray the silicone coating. We currently offer sprayable UV/dual cure products ranging from 500 to 5,000 cPs, and can adjust the viscosity to fit your specific need and application.

Semi-Flowable Products

Semi-Flowable ProductsThe semi-flowable class of UV/dual cure silicone products are often used in a dam and fill method. Dam and fill is a two-step process for fully encapsulating a component or section of the substrate. A dam is first created by outlining the perimeter, and then additional silicone material is dispensed to fill the dam center. Semi-flowables can also be used for staking, or adhering, a component to a circuit board.

Our encapsulating compounds offer exceptional insulation properties, vibration damping, and barrier protection against weather and severe environmental conditions.

As with all Novagard UV/dual cure silicone products, our semi-flowables exhibit excellent dielectric properties, are solvent free, and are 100% solids with no VOCs to handle or report. Little or no heat is generated during the curing process so parts remain cool, and you can process or package a part immediately – no racking required.

Viscosity for semi-flowables start at 5,000 cPs and are generally considered to be “self-leveling.” We also produce semi-flowables with a higher thixotropic ratio. The high thixo ratio ensures that once dispensed, the silicone holds its shape until cured. With its differing viscosity under shear vs at rest, our customers report that it dispenses into position easily, and once applied, stays firmly in place.

Gel Products

UV Dual Cure Silicone Gel ProductsUV/dual cure silicone gel products are typically used for potting or filling. Potting usually encases an entire PCB to protect it from environmental contaminants, and thermal or physical shock. Filling is used more in instances where only a certain component needs the additional protection or when a thicker (¾ inch to 1 inch) cross section is needed.

A UV/dual cure silicone gel offers low viscosity prior to curing, with good flow and wetting characteristics. Gels can adhere chemically, which is typical of silicones, and can adhere physically (they can be sticky).

Our class of gel products, once cured, measure lower in the Shore Hardness Scale – ranging from Shore 00 to low Shore A. We also have a “tough gel”  under development that registers in the mid-Shore A range. We can tailor a product to meet your precise requirements.

Paste Products

UV Dual Cure Silicone Paste ProductsUV/dual cure silicone paste products are mainly used for enclosure bonding, staking, or to create the dam in the first step of a dam and fill encapsulation process.

They serve as excellent adhesive/sealants with viscosities ranging from 100,000 to 500,000 cPs. As with most silicones, UV/dual cure silicone paste products have excellent dielectric properties and offer better protection from corrosion and other harsh environmental elements than other coating technologies. As design engineers become more familiar with the capabilities of UV/dual cure silicones, we anticipate them specifying these materials in a wider variety of applications.

Customized to Fit Your Application

Within our manufacturing site in Cleveland, OH beats the heart of our business: our R&D lab. As the largest R&D group in our class, we have significant expertise and experience in a wide array of technical disciplines. Our team includes experienced Ph.D. scientists and engineers along with subject matter experts who can customize our family of UV/dual cure silicone products to fit your exact needs.

Adhesion

Any of our UV/dual cure silicone products may be modified with adhesion promotors designed for specific substrates. Our products can adhere to:

  • FR4
  • PET (Mylar)
  • PBT
  • Polypropylene
  • Copper
  • Aluminum
  • Brass
  • Gold
  • Stainless Steel
  • Common metals and plastics used in electronics applications
Physical Properties

In addition to modifying adhesion profiles of any of our UV/dual cure silicone products, we can also adjust any of the following physical properties as needed:

Uncured:
Viscosity
Thixotropy
Pot life
UV tracer
Cured:
Shore hardness
Tensile strength
Adhesion
Elongation

 

Looking to the Future

As electronics continue to be embedded into the daily fabric of our lives, the need for UV/dual cure silicone products will only increase. “We see the market growing exponentially over the course of the next 3 to 5 years,” states Clark. “Consumers are looking for solidly built products and manufacturers are embracing solutions that allow them to cut processing time and cost while delivering world class protection of critical components.”

If you’re interested in learning more about our family of UV/dual cure silicone products, please fill out this form, email products@novagard.com, or call us at (216) 881-8111. We’d be happy to discuss your specific project.