Consistent Optical and Mechanical Performance – IOTA LEDH 3220 for SMD LEDs
For LED packagers seeking stable processing and field performance, the IOTA LEDH 3220 phenyl-type high refractive index encapsulant offers a practical choice. Engineered for SMD LED applications, it combines optical clarity with mechanical strength and environmental resilience.
The product is supplied as a two-part silicone with a mixing ratio of 1:5 (A:B). Viscosities at 25°C are 4,500 mPa·s (Part A) and 6,000 mPa·s (Part B), reaching a mixed viscosity of 6,000 mPa·s. This rheological profile allows for precise dispensing and efficient degassing. The recommended cure profile is 100°C for 1 hour, followed by 150°C for 3 hours, producing a crosslinked material with a Shore D hardness of 52D.
Key optical properties include a refractive index of 1.54 and a transmittance of 92%, supporting effective light output from encapsulated LEDs. Mechanical performance includes a tensile strength of 8 MPa and elongation at break of 40%, providing sufficient flexibility to accommodate thermal expansion mismatches between components.
Reliability features include good resistance to sulfur ingress and heat-induced degradation. These characteristics help maintain junction cleanliness and optical transmission over time. The material also demonstrates a moisture vapor transmission rate of 5.70 g/m²·24h and an oxygen transmission rate of 270 cm³/m²·24h. The coefficient of linear thermal expansion is 170 ppm, contributing to reduced interfacial stress during temperature cycling.
The IOTA LEDH 3220 is suitable for mid-to-high-power LED encapsulation where balance between hardness, optical performance, and environmental stability is required. It enables consistent packaging outcomes without overpromising on extreme conditions.