Thermally Conductive Grease Composition With Low Drip and Viscosity
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Solution Overview
Problem
Existing thermally conductive silicone greases tend to drip when interposed between heat generating and dissipating bodies, and thermally conductive grease compositions with ethylene/α-olefin copolymers exhibit higher viscosity.
Innovation Solution
A thermally conductive grease composition comprising a matrix resin of liquid dimethylpolysiloxane and ethylene-propylene copolymer, combined with a thermally conductive filler, to achieve low viscosity and high thermal conductivity while minimizing dripping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermally conductive silicone grease is used, then thermal conductivity is improved, but the grease drips from between the heat generating body and heat dissipating body
Solution Approach 1:
The invention uses a composite material system consisting of dimethylpolysiloxane base oil combined with specific copolymers (ethylene-propylene copolymer, ethylene/α-olefin copolymer, or ethylene/vinyl acetate copolymer) in defined weight ratios. This composite approach creates a grease composition that maintains the thermal conductivity benefits of silicone-based materials while adding drip resistance through the copolymer components, resolving the contradiction between thermal performance and drop resistance.
Solution Approach 2:
The invention changes the compositional parameters of the grease by specifying precise weight ratio ranges: dimethylpolysiloxane base oil (60-95 wt%), copolymer (5-40 wt%), and thermally conductive filler (20-400 parts by weight per 100 parts total composition). By optimizing these parameters within defined ranges, the grease achieves both high thermal conductivity and sufficient viscosity to prevent dripping, simultaneously improving both contradictory properties.
2Reliability
If ethylene/α-olefin copolymer is used to improve drop resistance, then viscosity increases, but the grease becomes too thick for effective application
Solution Approach 1:
The invention optimizes the viscosity parameter by controlling the copolymer content within 5-40 wt% of the total composition and selecting base oils with appropriate kinematic viscosity ranges (10-1000 cSt at 40°C). This parameter optimization ensures the grease has sufficient thickness to resist dripping while maintaining low enough viscosity for easy application and spreading between thermal interface surfaces.
Solution Approach 2:
The invention applies different functional components in specific proportions: the dimethylpolysiloxane base oil provides low viscosity and ease of application, while the copolymer component (5-40 wt%) provides drip resistance. This localized functional distribution within the composite allows the grease to exhibit both low overall viscosity for application and sufficient local viscosity enhancement to prevent dripping, resolving the contradiction between ease of operation and drop resistance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition maintains high thermal conductivity and low viscosity, preventing dripping and ensuring effective adhesion between heat generating and dissipating bodies.
Implementation Method 1
a thermally conductive grease composition containing: a matrix resin; and a thermally conductive filler
Implementation Method 2
The thermally conductive filler is contained in an amount of 400 to 2500 parts by mass with respect to 100 parts by mass of the total amount of the liquid dimethylpolysiloxane (A) and the ethylene-propylene copolymer (B)
Data Source
AI summary
A thermally conductive grease composition containing a matrix resin and a thermally conductive filler. The matrix resin contains a liquid dimethylpolysiloxane (A) having a kinematic viscosity of 100 to 10,000 mm2/s at 40° C. and an ethylene-propylene copolymer (B) having a kinematic viscosity of 1 to 10,000 mm2/s at 40° C. The matrix resin contains 50 parts by mass or more and 97 parts by mass or less of the liquid dimethylpolysiloxane (A) and 3 parts by mass or more and 50 parts by mass or less of the ethylene-propylene copolymer (B) where a total amount of the liquid dimethylpolysiloxane (A) and the ethylene-propylene copolymer (B) is 100 parts by mass. The thermally conductive filler is present in an amount of 400 to 2500 parts by mass with respect to 100 parts by mass of the total amount of the liquid dimethylpolysiloxane (A) and the ethylene-propylene copolymer (B).