Master Bond Inc. adhesives, sealants and coatings for optical, electro-optical and fiber-optic manufacturing applications feature outstanding spectral transmittance. Select grades can be formulated as high clarity and non-yellowing systems. Superior transparency, even in sustained high temperature situations, is a crucial characteristic of an optical adhesive. Optical adhesives are often the favored solution for LEDs, circuit boards, protective coatings on displays, LCDs and lasers and may be used as bondings, coatings or encapsulations. In addition to optical clarity and non-yellowing features, Master Bond’s adhesives for optical applications can be formulated to provide a variety of performance properties, from dimensional stability to low outgassing.

Performance properties of Master Bond optical adhesives

Master Bond’s optical adhesives can be formulated for additional performance properties including dimensional stability, low shrinkage, outstanding chemical and water resistance, abrasion resistance, and low outgassing. They can also be formulated for a range of refractive indexes from 1.43 to 1.61, resistance to 1,000 hours exposure to 85°c/85% humidity and more.

Case Study: potting application in a mini display system

A manufacturer of miniature display systems requested a low viscosity potting compound that was also optically clear and flexible. They wanted to know what Master Bond recommended. A variety of factors might change the recommended formulation.

One consideration is cure method and speed. If fast curing is the primary factor, UV15-7SP4 would be a possibility. This is a UV system that cures quickly when exposed to a UV light source between 320-365 nm. It also has low viscosity, non-yellowing properties and excellent flexibility.

For a room temperature curing system, Super Gel 9 is a two part urethane modified epoxy. It too, has low viscosity and exotherm, and may be cast in larger sections. It is ideal for encapsulating sensitive electronic parts and sealing delicate optical components.

Additional products for optical applications

• EP30-1 is a low viscosity, two component epoxy for high performance fiber optics bonding, coating, potting and encapsulation. It is especially recommended where low viscosity and superior dimensional stability are required. The system withstands chemical exposure while maintaining a spectral transmittance of over 97%. EP30-1 is widely used in the fiber optics field for applications ranging from bonding ferrules and connectors to potting LED devices and fiber optics components.
• EP37-3FLF forms very flexible high strength bonds that offer excellent impact resistance as well as resistance to severe thermal cycling and shock. This optically clear, two part epoxy bonds well to a wide variety of substrates including metals, glass, ceramics, rubber and many plastics. Its relatively low exotherm makes it  just the material for large castings.
• MasterSil 151 features outstanding electrical insulation properties and a low viscosity, and is often recommended for high performance potting, casting and encapsulation. This flexibilized system provides superior resistance to vibration and shock as well as high strength and elongation. Serviceable over the wide temperature range of -65°F to +400°F, MasterSil 151 cures at room temperature or faster at elevated temperatures.

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