The Universal Selection Source:
Plastics & Elastomers
Product News

WACKER at PCIM: Launches Silicone Rubber Gap Filler for Electronics Applications

Published on 2016-05-10. Author : SpecialChem

WACKER, the Munich-based chemical company, showcases a new heat-conducting silicone-based gap filler material for the electronics industry at the Power Conversion and Intelligent Motion electronics tradeshow PCIM Europe. Available under the tradename SEMICOSIL® 961 TC, the silicone rubber is ideal as an interface material for thermally connecting electronic circuits, ensuring effective heat management. The product is characterized by good flow and processing properties. Furthermore, wear of the mixing and metering equipment used in its application is low. This year’s PCIM takes place in Nuremberg, Germany, from May 10 to 12.

Fig. 1: WACKER

With the new silicone gap filler material, WACKER is expanding its portfolio of thermal interface materials. SEMICOSIL® 961 TC is a highly filled, two-part silicone rubber that cures at room temperature via a platinum-catalyzed addition reaction to form a soft silicone elastomer with a tacky surface. The cured rubber achieves a thermal conductivity of two watts per meter kelvin and, at the same time, is electrically insulating.

Before it cures, SEMICOSIL® 961 TC is a non-sag material. However, its viscosity decreases with increased shearing, for example during mixing and metering. Its shear-thinning property is adjusted so that the silicone rubber can easily be fed by machine and applied as a bead. Processors can achieve a high metering rate and very high dosing accuracy.

SEMICOSIL® 961 TC ensures optimum heat transfer from the electrical circuit to a heat sink. In practice, the gap filler is first applied to the heat sink. The circuit board is then pressed on or fitted by means of a vacuum process. During compression, a continuous film forms that conforms snugly to the surfaces of the two joining parts. In this way, surface irregularities and tolerances can be evened out perfectly. Furthermore, the film maximizes the contact area and thus promotes heat transfer.

WACKER at PCIM: Launches Silicone Rubber Gap Filler for Electronics Applications
Fig. 2:
WACKER at PCIM: Launches Silicone Rubber
Gap Filler for Electronics Applications

The film cures to form a silicone layer between the joining parts. Thanks to its soft consistency, it ensures a reliable, tight fit even if there are frequent temperature changes and vibrations. In addition, the new silicone gap filler can be used over a wide temperature range. Its properties remain unchanged between -45 and +180 degrees Celsius. High thermal and thermal-shock resistance and the ability to absorb vibrations are important for applications in automotive electronics and electromobility, for example.

SEMICOSIL® 961 TC is a two-component system. Despite its high filler loading, it has a comparatively minor abrasive effect on the mixing and metering equipment used to apply it. This means that there is less abrasive damage to feed pumps, for example, than is usually the case with highly filled silicone rubber. Consequently, significantly longer service lives of mixing and metering equipment and major cost advantages in processing are possible.

The new gap filler contains hardly any volatile components. In terms of fire-safety properties, tests show that the silicone product meets the specifications for classification V-0 as per UL 94 of Underwriters Laboratories. SEMICOSIL® 961 TC is available in both Euro cartridges and 30-kilogram pails.


WACKER is a globally-active chemical company with some 16,700 employees and annual sales of around € 4.83 billion (2014). WACKER has a global network of 25 production sites, 21 technical competence centers and 48 sales offices.

WACKER Silicones

Silicone fluids, emulsions, rubber and resins; silanes; pyrogenic silicas; thermoplastic silicone elastomers.

WACKER Polymers

Polyvinyl acetates and vinyl acetate copolymers in the form of dispersible polymer powders, dispersions, solid resins and solutions used as binders for construction chemicals, paints and coatings, adhesives, plasters, textiles and nonwovens, as well as for polymeric materials based on renewable resources.

WACKER Biosolutions

Biotech products such as cyclodextrins, cysteine and biologics, as well as fine chemicals and PVAc solid resins.

WACKER Polysilicon

Polysilicon for the semiconductor and photovoltaic industries.


Hyperpure silicon wafers and monocrystals for semiconductor components.

Source: WACKER

PS: If you liked this News, you might enjoy our Plastics & Elastomers Product Newsletter. All the Product News delivered once a week right to your inbox. Sign up here!

Fluoropolymers and chemistry that make a difference
The Chemicals Sales & Marketing Toolbox
Back to Top