Stycast 1265

Stycast 1265 is a clear, two-component, epoxy encapsulant specifically engineered for embedding stress-sensitive electronic components. Designed to cure into a soft, resilient gel, it provides a protective “cushion” that absorbs mechanical shock and thermal expansion stresses. Because the material remains transparent and relatively soft after curing, it is ideal for applications requiring visual inspection or the potential for component repair and replacement.

In its uncured state, Stycast 1265 consists of a resin (Part A) and an amine hardener (Part B) that are mixed at a simple 1:1 ratio by weight. The mixed system features a remarkably low viscosity of 600 mPa·s and an exceptionally long work life of over 24 hours for a 100g mass. This long pot life and low exotherm make it particularly suited for large-scale castings where heat buildup during the curing process must be avoided. To ensure a void-free embedment, vacuum deairing at 1 to 5 torr is recommended before pouring the mixture into the mould or cavity.

The curing profile is highly flexible, allowing the material to set over 3 to 7 days at room temperature (25°C) or as quickly as 4 hours at 95°C. Once cured, the encapsulant exhibits a Shore A hardness of approximately 25, which can be slightly adjusted by varying the cure temperature. It offers excellent electrical insulation with a volume resistivity of 1×10¹² ohm-cm and a dielectric constant of 3.0. A unique feature of Stycast 1265 is its repairability: the gel can be easily cut away to replace a component, and fresh material can be poured into the void and cured to restore a seamless, perfect seal.