The Application
A customer that manufactures mini display systems is looking for an optically clear, flexible compound. It is also very important that the product has a low viscosity, as it will be used for potting in a new product they are developing.
Finding the Answers
- Does the material need to cure quickly?
- Can you add heat for curing?
- What are the dimensions of the potting?
- Do you have a refractive index requirement?
- Do you have a desired hardness value for the material?
The Solution
Based on the answers to the questions above, Agnes made several recommendations that all met the clarity, viscosity and flexibility requirements. If a rapid cure was the primary consideration, Master Bond UV15-7SP4 would fit the bill with cures in 10-30 seconds upon exposure to a UV light source emitting at a wavelength of 320-365 nm. This one part UV system is very easy to handle and can be cured in sections approaching 1/4 inch thick.
For a deeper cure, MasterSil 151 would be well suited as it features the ability to cure in thicknesses beyond 1 inch. Since it is a silicone system, it offers exceptional flexibility and high temperature resistance. MasterSil 151 is an addition cured system and does not require exposure to moisture for complete crosslinking.
Master Bond has options for when a silicone or UV system wouldn't be appropriate. Super Gel 9 is a two component, urethane modified epoxy system that cures readily at room temperature to form a soft, resilient, gel-like system with dimensional stability. It has extremely low viscosity and exotherm, enabling it to be cast in larger sections. Its combination of properties enables it to be used for encapsulating sensitive electronic parts and sealing delicate optical components.
EP37-3FLF is also a superb optically clear potting, encapsulating and casting system. It has very low viscosity and is low in exotherm, which is another consideration for relatively large castings. As with the other compounds, it possesses superior electrical insulation properties. This two component epoxy has a convenient one to one mix ratio by weight or volume and has a longer working life.
Summary of Products
| Product | Chemistry | Cure Type | Viscosity | Refractive Index | Flexibility |
|---|---|---|---|---|---|
| UV15-7SP4 | One part UV system | UV | Very low | 1.531 | Yes |
| MasterSil 151 | Two part silicone | Room temperature or heat | Very low | 1.43 | Yes |
| Super Gel 9 | Two part urethane modified epoxy gel | Room temperature or heat | Low | 1.5253 | Yes |
| EP37-3FLF | Two part epoxy | Room temperature or heat | Very low | 1.51 | Yes |
Meet Our Tech Expert: Agnes Brenson
Agnes Brenson earned a double degree in engineering from Stevens Institute of Technology. She puts her engineering skills to use on a daily basis by helping clients determine the best suited materials for process and application requirements. Often, challenging applications also require an investigation into adhesive modifications to solve the situation at hand.
