Moisture-Curable Thermal Interface Composition With Lower Filler Density
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Solution Overview
Problem
Conventional thermal interface materials rely on high weight percentages of expensive metals like silver or inorganic fillers such as aluminum nitride or boron nitride to achieve desired thermal conductivity, leading to high product density, cost, and environmental concerns, while silicone-based materials pose contamination risks and polyurethane solutions have health and flexibility issues.
Innovation Solution
A two-part curable composition comprising a first part with a metal catalytic component, non-reactive diluent, wetting agent, filler, and rheology modifier, and a second part with silane terminated polyurethane polymer, moisture scavenger, filler, and wetting agent, which cures to form a thermally conductive product with balanced properties, including thermal conductivity, flexibility, and environmental safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high weight percentages of expensive metals like silver or inorganic fillers such as aluminum nitride or boron nitride are used to achieve desired thermal conductivity, then thermal conductivity is improved, but product density and cost increase
Solution Approach 1:
The patent uses a composite material system combining silane-terminated polyurethane polymer with aluminum oxide filler particles. This composite achieves thermal conductivity of 2.0 to 5.0 W/m·K with a balanced density of 2.0 to 3.2 g/cm³, resolving the contradiction between thermal performance and weight by creating a synergistic material system rather than relying on high concentrations of single high-performance fillers
Solution Approach 2:
The patent optimizes the filler weight percentage to a specific range (30-80%) rather than using high weight percentages conventionally. This parameter change achieves effective thermal conductivity while controlling density, as the silane-terminated polyurethane matrix provides adequate thermal transmission at moderate filler concentrations
2Temperature
If high weight percentages of expensive metals like silver or inorganic fillers such as aluminum nitride or boron nitride are used to achieve desired thermal conductivity, then thermal conductivity is improved, but manufacturing cost increases
Solution Approach 1:
The patent substitutes expensive metals like silver and inorganic fillers like aluminum nitride or boron nitride with aluminum oxide, a more cost-effective filler material. This replacement maintains adequate thermal conductivity (2.0 to 5.0 W/m·K) while significantly reducing material costs, making the thermal interface material more economically viable for mass production
3Temperature
If silicone-based materials are used for thermal interface, then thermal conductivity is achieved, but contamination risks increase
Solution Approach 1:
The patent extracts the problematic silicone base material from the formulation and replaces it with silane-terminated polyurethane polymer. This extraction eliminates the contamination risks associated with silicone while maintaining the thermal conductivity function through the alternative polymer matrix combined with aluminum oxide filler
4Ease of manufacture
If conventional polyurethane solutions are used for thermal interface, then ease of manufacture is improved, but health and flexibility issues arise
Solution Approach 1:
The patent modifies the polyurethane chemistry by using silane-terminated polyurethane polymer that cures via moisture cure mechanism. This parameter change in the curing chemistry eliminates health concerns associated with conventional polyurethane isocyanate systems while maintaining ease of manufacture and achieving flexible cured properties suitable for thermal interface applications
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 achieves thermal conductivity ranging from 2.0 to 5.0 W/m·K, low density (2.0 to 3.2 g/cm³), and excellent mechanical properties, with minimal environmental impact and reduced manufacturing costs, suitable for bonding heat-generating components in electric vehicles.
Implementation Method 1
silane terminated polyurethane (STP) polymers crosslinked by moisture
Implementation Method 2
at least one metal catalytic component for catalyzing the cure reaction
Implementation Method 3
thermal interface materials are employed for functional sheets, integrated circuit (IC) packaging, heat sinks... Thermal interface materials comprising particles of, for example, aluminum oxide, silicon nitride, aluminum nitride, boron nitride, graphite and carbon nanotubes, which are useful for heat dissipation
Data Source
AI summary
A two-part curable composition which cures to form a thermally conductive cured product, including: (a) a first part including: (1) at least one metal catalytic component for catalyzing the cure reaction; (2) a non-reactive diluent component; (3) a wetting agent component; (4) a filler component; (5) a rheology modifier component; and (6) a pigment component; and (b) a second part including: (1) at least one silane terminated polyurethane polymer; (2) a moisture scavenger; (3) a non-reactive diluent component; (4) a filler component; and (5) a wetting agent component, wherein at least one of the filler components of the first-part and the second-part comprises a thermally conductive filler.