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.
In order to find the appropriate solution, the crucial questions for Master Bond to the user were:
- 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?
Based on the answers to the questions above, Master Bond's tech expert Agnes Brenson 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 ¼ 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 good 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.