Gap filler

Thermal management

Gap fillers are soft, elastic, relatively thick thermal pads with heat-conducting properties. Thanks to their material thickness and elasticity, they compensate for height differences between components. This means, for example, that entire PCBs with different component heights can be connected to a heat sink. Gap fillers are also permanently elastic to compensate for thermal expansion coefficients (cte) and reduce stress caused by vibrations. Due to their low hardness, no high forces (contact pressure) are required to connect them to surfaces. They are therefore also suitable for mechanically sensitive components and assemblies (e.g. no bending of the PCB).

In many cases, the low natural self-adhesion of the gap fillers allows for simplified pre-assembly. Where stronger adhesive forces are required, self-adhesive versions can also be used.

More stress-resistant version thanks to additional Kapton® MT insulation

Gap fillers achieve their good conformability to different surfaces by reversibly (within limits) yielding sideways to the pressure. The thickness of the material and therefore the breakdown voltage is reduced at these pressure-loaded points. If a safe and reliable galvanic separation is required, a combination of a thin Kapton® MT film (Rth = 0.06 K/W) with a gap filler is recommended. The Kapton® film has a very high dielectric strength and hardly impedes the heat flow due to its low thickness (25µm).

Thermal Management - Gap-Filler

Hinweis: alle wärmeleitenden Materialien sind prinzipiell nicht komprimierbar. Weiche Gap-Filler reduzieren ihre Dicke durch Verformung. Unter Druck wird das Material seitwärts aus dem Druckbereich herausgepresst. Wo solch ein Auspressen nicht möglich ist (z.B. große Flächen von >10 cm²), kann auch die Materialdicke nicht wesentlich reduziert werden. Bei den meisten Anwendungen ist jedoch durch unterschiedliche Bauteilhöhe eine Materialverschiebung in Bereiche rund um die höchsten Bauteile möglich. Durch eine Dickenreduktion verändert sich auch die Spannungsfestigkeit!

All gap fillers can be supplied in the form of sheets (in the standard format or smaller) or customized as loose individual parts or as formed parts on sheets.

Select the desired thermal conductivity:


Thermal conductivity: 1.3 W/mK

CMC 15023

Gap filler
Adhesive on one side
Shore 00=5
Dielectric strength: 6 kV/mm

Available in the following thicknesses:

1.0 mm / 1.5 mm / 2.0 mm / 2.5 mm / 3.0 mm / 3.5 mm / 4.0 mm / 4.5 mm / 5.0 mm / 6.0 mm / 6.5 mm

Gap-Filler CMC 15023


Thermal conductivity: 2.0 W/mK

CMC 15014

Gap filler
one-sided adhesive
Shore 00= 20
Dielectric strength: > 10 kV/mm

Available in the following thicknesses:

0.5 mm / 1.0 mm / 1.5 mm / 2.0 mm / 2.5 mm / 3.0 mm / 3.5 mm / 4.0 mm / 5.0 mm / 6.0 mm

Gap-Filler CMC 15014


Thermal conductivity: 3.2 W/mK

CMC 15306

Gap filler
adhesive on both sides
Shore 00= 37
Dielectric strength: 15 kV/mm

Available in the following thicknesses:

0.5 mm / 1.0 mm / 1.5 mm / 2.0 mm / 2.5 mm / 3.0 mm / 4.0 mm / 5.0 mm

Gap-Filler CMC 15306


Thermal conductivity: 4.5 W/mK

CMC 15307

Gap filler
adhesive on both sides
Shore 00= 60
Dielectric strength: 15 kV/mm

Available in the following thicknesses:

0.5 mm / 1.0 mm / 1.5 mm / 2.0 mm / 2.5 mm / 3.0 mm / 4.0 mm / 5.0 mm

Gap-Filler CMC 15307


Thermal conductivity: 5.0 W/mK

CMC 15020

Gap filler
adhesive on both sides
Shore 00= 65
Dielectric strength: > 10 kV/mm

Available in the following thicknesses:

1.0 mm

Gap-Filler CMC 15020


Thermal conductivity: 5.5 W/mK

CMC 15308

Gap filler
adhesive on both sides
Shore 00= 55
Dielectric strength: 10 kV/mm

Available in the following thicknesses:

0.5 mm / 1.0 mm / 2.0 mm

Gap-Filler CMC 15308

CMC 15309

Gap filler
one-sided adhesive
Shore 00= 55
Dielectric strength: 10 kV/mm

Available in the following thicknesses:

0.5 mm

Gap-Filler CMC 15309

CMC 15041

Gap filler
adhesive on one side
Shore 00= 55
Dielectric strength: 10 kV/mm

Available in the following thicknesses:

1.0 mm

Gap-Filler CMC 15041

CMC 15042

Gap filler
adhesive on one side
Shore 00= 55
Dielectric strength: 10 kV/mm

Available in the following thicknesses:

2.0 mm

Gap-Filler CMC 15042