Low temperature curable epoxy siloxane hybrid materials for LED encapsulant

• Published in: Journal of applied polymer science Vol. 131; no. 6; pp. np - n/a
• Main Authors: Kim, HweaYoon, Bae, Jun-young, Kim, Yong Ho, Kim, Yu Bae, Bae, Byeong-Soo
• Format: Journal Article
• Language: English
• Published: Hoboken, NJ Blackwell Publishing Ltd 15.03.2014; Wiley; Wiley Subscription Services, Inc
• Subjects: Anhydrides; Applied sciences; Chemical modifications; differential scanning calorimetry; Exact sciences and technology; Inorganic and organomineral polymers; Materials science; optical properties; packaging; Physicochemistry of polymers; Polymers; thermal properties; thermogravimetric analysis; Transparency; Transport properties; Property composition relationship; Thermal ageing; Refraction index; Oxetane derivatives; Plastic packaging; Thermal stability; Crosslinked copolymer; Steam permeability; Optical properties; Siloxane polymer; Cationic copolymerization; Mechanical properties; packaging; thermogravimetric analysis; Glycidyl ether copolymer; Hardness; Experimental study; Light emitting diode; Thermal properties; Humidity effect; differential scanning calorimetry; Epoxide; Prepolymer; Ring opening copolymerization; Siloxane copolymer
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.39968

ABSTRACT A thermally cured epoxy‐siloxane hybrid material that is curable at low temperature (L‐expoxy hybrimer) was investigated for use as an LED encapsulant. This new hybrimer was fabricated using thermally initiated, cationic polymerization of cycloaliphatic epoxy oligosiloxane (CAEO) resin, derived from non‐hydrolytic sol–gel, mixed with oxetane hardener in the presence of a hexafluoroantimonate‐type thermo‐cationic initiator. The L‐epoxy hybrimer was cured at a lower temperature (below 120°C) than previously reported for an epoxy hybrimer with anhydride hardener (above 180°C). The L‐epoxy hybrimer showed high thermal resistance to yellowing under long‐term high temperature condition, and maintained good optical transmittance. Also, it had a high refractive index (up to 1.57), as well as the hardness (Shore D 80), and low water‐vapor permeability, when the new hybrimer was used to encapsulate an LED, it showed good adhesion without cracks or delamination and maintained their initial performance after the long‐term aging tests (120 and 85°C at 85% humidity). © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014, 131, 39968.