SEMICOSIL® 911 A/B
SEMICOSIL® 911 A/B is a pourable, addition-curing, two-part silicone rubber that cures to a soft silicone gel.
- two-part, 1 : 1 mixing ratio
- rapid heat cure
- forms a soft gel on vulcanization
- low content of volatiles
- low content of uncured polymer
- almost constant properties between -40 °C and +180 °C
- low ion content
Because of the thixotropic behaviour, SEMICOSIL® 911 A/B is specially recommended for local encapsulation of delicate electronic components.
All surfaces must be clean and free of contaminants that will inhibit the cure of SEMICOSIL® 911 A/B. Examples of inhibiting contaminants are sulfur containing materials, plasticizers, urethanes, amine containing materials and organometallic compounds – especially organotin compounds. If a substrate’s ability to inhibit cure is unknown, a small scale test should be run to determine compatibility.
Component A of SEMICOSIL® 911 A/B contains the platinum catalyst, component B the crosslinker. Even traces of the platinum catalyst may cause gelling of the component containing the crosslinker. Therefore tools (spatula, stirrers, etc.) used for handling the platinum-containing component or the catalyzed compound must not come into contact with this component. The two components should be thoroughly mixed at a 1 : 1 ratio by weight or volume. To eliminate any air introduced during mixing or trapped under components or devices a vacuum de-airing under a vacuum of 10 - 20 mm mercury for 5 - 10 min is recommended.
Curing time of addition-curing silicone rubber is highly dependent on temperature, size and heat sink properties of the component being potted.
Temperature Curing time
100 °C 5 min
130 °C 2 min
We recommend running preliminary tests to optimize conditions for the particular application. Comprehensive processing instructions are given in our leaflet "Wacker RTV-2 Silicone Rubber - Processing".
The 'Best use before end' date of each batch is shown on the product label.
Storage beyond the date specified on the label does not necessarily mean that the product is no longer usable. In this case however, the properties required for the intended use must be checked for quality assurance reasons.