SEMICOSIL® 917 is a shear-thining, addition-curing, 2-part silicone rubber that cures to a soft silicone gel when mixed with ELASTOSIL® CAT PT, ELASTOSIL® CAT PT-F, ELASTOSIL® CAT UV or SEMICOSIL® 950 UV B.


• 10 : 1 mixing ratio
• Shear-thinning
• Fast curing at room temperature with Catalyst PT-F
• Long pot life at room temperature with Catalyst PT
• Extremely fast curing with Catalyst UV
• Shadow cure with SEMICOSIL® 950 UV B
• Low Hardness
• Pronounced tackiness
• Cured properties independent on catalyst
• UV tracer for automated visual inspection


All the information provided is in accordance with the present state of our knowledge. Nonetheless, we disclaim any warranty or liability whatsoever and reserve the right, at any time, to effect technical alterations. The information provided, as well as the product's fitness for an intended application, should be checked by the buyer in preliminary trials. Contractual terms and conditions always take precedence. This disclaimer of warranty and liability also applies particularly in foreign countries with respect to third parties' rights.

Comprehensive instructions are given in the corresponding Material Safety Data Sheets. They are available on request from WACKER subsidiaries or may be downloaded via WACKER web site

Encapsulation of electronic components for the
automotive and power electronics industries.

All surfaces must be clean and free of contaminants that will inhibit the cure of SEMICOSIL® 917.

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.

SEMICOSIL® 917 contains the crosslinker, ELASTOSIL® CAT PT, PT-F, UV and SEMICOSIL® 950 UV contains the catalyst. Even traces of the platinum catalyst may cause gelling of the component containing the crosslinker. Therefore tools (spatula, stirrers, etc.) used for handling the catalyst-containing component or the catalyzed compound must not come into contact with this component.

The two components should be thoroughly mixed at a 10 : 1 ratio by weight or volume.

To eliminate any air introduced during dispensing or trapped under components or devices a vacuum encapsulation is recommended.

The system SEMICOSIL® 917 / ELASTOSIL® CAT UV (10:1) is activated by direct UV irradiation. UV irradiation should use emissions in the wavelength range between 250 and 350 nm.

The system SEMICOSIL® 917 / ELASTOSIL® CAT UV (10:1) is activated by direct UV irradiation. UV irradiation should use emissions in the wavelength range between 250 and 350 nm.

Typically D-bulbs (Fe-doped Hg-light sources) using ozone-free quartz should be used and are commercially available. H-bulbs with emissions below 250 nm are not recommended.

Curing time of the UV-active system SEMICOSIL® 917 / ELASTOSIL® CAT UV (10:1) is highly dependent both on the intensity and dose of the UV-light and the spectral intensity distribution. The curing is also dependent on the layer thickness, the optical properties of the substrate and temperature. Increase of the temperature will fasten curing reaction.


SEMICOSIL® 917 / ELASTOSIL® CAT UV (10:1) will only cure in directly irradiated areas. The combination
SEMICOSIL® 917 / SEMICOSIL® 950 UV B features same UV reactivity, but additionally ensures that the
silicone also can be cured in shadow areas which are not directly irradiated with light.

For fast cure a vented oven can be used.


SEMICOSIL® 917 should be stored dry and cool in the
tightly closed original container.
The 'Best use before end' date of each batch appears
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

Sales and support

Wacker Chemical Corporation
3301 Sutton Road
Adrian, MI 49221-9397
United States
+1  888  922-5374 (Phone)

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