Jul 15 2008
WACKER, the Munich-based chemical group, has succeeded in developing UV-active silicone elasto-mers with a significantly enhanced property profile. Marketed under the tradename SEMICOSIL® UV, the new silicone grades cure at room temperature within a few minutes.
SEMICOSIL® UV silicone elastomers cure within a few minutes. The UV dose and the silicone grade determine the curing rate. SEMICOSIL® UV generates no by-products during curing, thus making it ideal for micro-electronic and sensor technology applications.
The curing rate can be controlled by adjusting the UV dose as required. This enables manufacturers to encapsulate electronic components and PCBs faster and more economically. SEMICOSIL® UV is particularly suitable for key future markets – from automotive and power electronics through to sensor technology.
The novel UV-active silicone elastomers are easy-to-manage one- and two-component systems based on polyorganosiloxanes. The elastomers are characterized by a long shelf life, fast processing and the absence of any by-products on curing.
Such properties are much sought after, especially for the encapsula-tion of electronic components. UV-curing epoxy- or acrylate-based polymers are frequently used to protect these devices. In both cases, curing requires the addition of photoinitiators. These leave either ions or free-radical decomposition products in the material, which can considerably impair quality, especially in electronic applications.
These drawbacks need not be feared when UV-active silicones are used, since SEMICOSIL® UV cures without photoinitiators. In addition, the product offers processors maximum flexibility. The curing rate can be accurately controlled by appropriate selection of elastomer, UV dose and process temperature. Even at room temper-ature, SEMICOSIL® UV offers very short activation and curing times. In consequence, cycle times for coating electronic components can be drastically reduced, even without oven curing. This boosts produc-tivity and lowers energy and production costs, especially in the case of large components.
SEMICOSIL®
For years, WACKER SILICONES has supplied a range of both heat-curing and RT-curing two-component silicone rubber grades – marketed under the tradename SEMICOSIL® UV – for use in the microelectronics industry. Encapsulation offers particularly efficient protection for microelectronic components. SEMICOSIL® is also used for coating PCBs and hybrid components (conformal coating). A pro-tective coating of this kind is cost-efficient in production and is useful wherever assemblies have to meet stiff requirements in terms of quality, reliability and correct functioning.