C. Thermal / Composite Materials

Thermal Grease TIM2

TIM2 Thermal Grease is a high-performance thermal interface material designed for gap-filling applications between heat sources and heat sinks, including CPUs, GPUs, Power Modules, Cold Plates, and various cooling systems. It effectively fills microscopic surface gaps at the interface, reducing thermal resistance and improving overall heat dissipation efficiency. The product features excellent thermal conductivity, stable viscosity, and good printability for processing, while maintaining reliable thermal performance during long-term operation. The product series includes both silicone-based and non-silicone formulations. The non-silicone thermal grease offers low volatility and low oil bleeding, making it ideal for applications requiring higher cleanliness and reliability.

GTA provides multiple model options, as shown below, to deliver optimal solutions for various thermal management needs.

Basic components of GTA Thermal Grease

Component	Function
Base Oil	Flowability, interface wetting	- Silicone-based：Silicone oil
Base Oil	Flowability, interface wetting	- None-Silicone-based：low Tg acrylic polymer
Thermal Filler	Provides thermal conduction pathways (Aluminum, Aluminum Oxide, Zinc Oxide)
Additives	Stability, anti-separation properties

Technical Specifications of GTA Thermal Grease

Item	Cause / Concern	GTA Result
Oil Bleeding	Poor compatibility between base oil and filler	Pass
High-Temperature Long-Term Reliability	150 ^oC x 1000h may cause dry-out, increased thermal resistance, and powdering	Pass
Silicone Sensitivity of System	Low-molecular-weight siloxanes (L-MW siloxanes) may volatilize during thermal cycling. The evaporated silicone vapor can contaminate circuit boards and optical communication modules.	Non-silicone HSG-A501

Scenario

Specification

Item	Unit	None-Silicone-based HSG-S331	None-Silicone-based HSG-A501	None-Silicone-based HSG-A601	Silicone-based HSA-S501
Viscosity	Pa-sec	550	1900	1200	1800
Specific Gravity	-	2.6	2.4	2.2	2.4
Non-volatile Content 150^oC x 3h	%	99.8	99.9	98.5	99.9
Thermal Conductivity^** Hot Disk, isotropic	W/m·K	3.3	5.1	6.0	5.0
Thermal Impedance^* @40psi & 80^oC	°C·cm²/W	0.18	0.04	0.10	0.04
Bond line Thickness@40 psi& 30^oC	mm	0.046	0.02	0.047	0.02

* Hot plate method, ASTM D5470, LW-9389. **Hot disk method, ISO 22007-2, TPS 500 S.

High temperature reliability test of TIM2

Thermal grease HSG-S501 and Dow 5888 were stored at 150°C for 1,500 hours. Both Thermal resistance and viscosity showed an increasing trend over time, with changes remaining within the same order of magnitude.

–Aging Conditions: air circulating oven at 150°C
–During the aging test, samples of thermal grease were taken out every 100–200 hours for viscosity and thermal resistance measurements.