Thermal Grizzly launches PhaseSheet PTM Pro with a new composition and an easier to remove liner

Thermal Grizzly has introduced PhaseSheet PTM Proa new version of its phase change thermal foil for processors and graphics chips. The manufacturer has modified the composition to improve thermal conductivity and changed the support film that is removed during installation.

The sheet of 40×40mm It already appears in its European store for 19.90 euros, with VAT included and shipping apart. The innovations affect both the material that transmits heat and its handling, a part of the assembly in which a sheet can break when separating the protections.

An easier to remove backing film

Thermal Grizzly notes that the new support Peels off more easily on both sides. This aims to reduce the risk of tearing the material before placing it between the chip and the heatsink. The sheet arrives solid and can be handled at room temperature.

The brand also announces an improvement in conductivity compared to PhaseSheet PTM. The published information does not specify this difference with a value in W/mK or with a temperature reduction in degrees. The improvement remains, therefore, a statement by the manufacturer pending a comparison measured under the same conditions.

PhaseSheet PTM Pro does not conduct electricity. Its main applications are processors and GPUs, where the material occupies the space between the two surfaces and facilitates heat transfer to the cooling system.

The material begins to liquefy above 45 °C

The sheet is made of a phase change material, known as acronym PCM. At room temperature it remains solid and begins to liquefy when it exceeds 45 °C. During operation it can adapt to the contact between the chip and the base of the heatsink in a similar way to thermal paste.

When cooled it returns to the solid state. This behavior is repeated with the load and rest cycles of the equipment, while the support film only intervenes in the installation and must be removed before using the material.

To distribute it in a thin layer, the marking indicates an approximate assembly force of 300 to 400 N. It is a condition of application of the product: the pressure between the surfaces intervenes in how the material spreads once it reaches the phase change temperature.

The brand describes a very low viscosity in liquid state and a contraction upon re-solidification. This behavior is related to one of the problems that this type of interface tries to reduce: the displacement of thermal paste during heating and cooling cycles.

The problem of pasta displacement

The silicon of the chip and the copper of the heatsink expand differently when heated. In each cycle, small deformations can occur in the contact surfaces, which recover their shape when cooled.

Over time, that movement can push some of a thermal paste toward the edges and reduce the amount that remains in the contact area. The phenomenon is often called pump out and is especially relevant in assemblies with a copper base on a graphics chip.

Thermal Grizzly claims that the solidification and shrinkage of PhaseSheet PTM Pro helps limit that displacement. The company thus maintains the operating principle of PhaseSheet PTM, with a new composition and a revised support film.