WMC-G279 | White Epoxy Molding Compound

OPTOLINQ™ WMC-G279 is a white, halogen-free, light-transmitting epoxy molding compound developed for photocoupler and optocoupler packages. It is formulated for good moldability and low-stress encapsulation, with a spiral flow of 85 cm and gel time of 22 s at 175 °C. The cured compound provides a glass transition temperature of 180 °C, flexural strength of 155 MPa, and flexural modulus of 16.6 GPa at 25 °C, supporting package integrity during molding, post-cure, and downstream thermal exposure.

For electrical and environmental reliability, WMC-G279 combines low ionic contamination, 0.5% water absorption after PCT 24 h, extract pH of 6.7, and extract conductivity of 40 µS/cm. It also provides volume resistivity of 5.0 × 1015 Ω·cm at 25 °C, CTI of 300 V, and UL 94 V-0 flammability. Optical performance is defined by 20% transmittance at 2 mm thickness at 940 nm, making it suitable for optocoupler designs that depend on controlled light transmission rather than reflective cavity behavior. For similar optical isolation molding applications, OPTOLINQ™ WMC-G279 can be positioned as a close functional alternative to Hysol GR180T.

Key Features

• White transmitting formulation: Supports optical transmission in photocoupler and optocoupler package designs.
• Good moldability: 85 cm spiral flow at 175 °C supports practical transfer molding behavior.
• Fast gel time: 22 s at 175 °C supports efficient molding cycles.
• High thermal stability: Tg of 180 °C supports reflow and thermal cycling robustness.
• Low moisture uptake: 0.5% water absorption after PCT 24 h helps limit moisture-driven reliability risk.
• Low ionic contamination: Low chloride and sodium levels support long-term electrical reliability.
• Electrical insulation capability: Volume resistivity of 5.0 × 1015 Ω·cm and CTI of 300 V support isolation-focused packages.
• UL 94 V-0 flame rating: Meets a common flammability requirement for electronic package materials.

Applications / Suitable For

• Photocouplers
• Optocouplers
• Optical isolators / opto-isolators
• Transfer-molded optoelectronic isolation packages
• Packages requiring white transmitting EMC behavior
• Applications requiring halogen-free EMC and UL 94 V-0 performance