SEMICOSIL® 915 HT is a pourable, addition-curing, 2-part silicone that cures to a silicone gel when mixed with ELASTOSIL® CAT PT, ELASTOSIL® CAT PT-F or ELASTOSIL® CAT UV.


  •  two-part, 10 : 1 mixing ratio
  •  low viscosity
  •  fast curing at room temperature with ELASTOSIL® CAT PT-F
  •  long pot life at room temperature with ELASTOSIL® CAT PT
  •  extremely fast curing with ELASTOSIL® CAT UV
  •  medium gel hardness
  •  excellent tackiness
  •  excellent heat resistance at 210°C

Encapsulation of electronic components for the power electronics industries.

All surfaces must be clean and free of contaminants that will inhibit the cure of  SEMICOSIL® 915 HT.

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® 915 HT contains the crosslinker, ELASTOSIL® CAT PT, PT-F and CAT UV contain 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.

Curing of SEMICOSIL® 915 HT catalyzed with ELASTOSIL® CAT PT or ELASTOSIL® CAT PT-F (10:1) is possible at ambient temperature (ca. 23°C) and is promoted by elevated temperature.

For fast cure a vented oven can be used.


The system SEMICOSIL® 915 HT / 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® 915 HT / 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® 915 HT / ELASTOSIL® CAT UV (10:1) will only cure in directly irradiated areas.


SEMICOSIL® 915 HT should be stored dry and cool in the tightly closed original container.

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.

Sales and support

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

How can we help you?

  • Do you need help in choosing a product or do you require technical support? If so, please contact our experts.
Ask a question


My media

My favorites

My products