Thermally Conductive Sheet Using Zinc Oxide Acicular Crystals
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Solution Overview
Problem
Current thermally conductive materials and sheets fail to provide excellent thermal conductivity, electrical insulation, flexibility, and toughness, leading to inefficiencies in heat dissipation and potential contamination in electronic devices due to issues like silicone grease leakage and poor compatibility with semiconductor elements.
Innovation Solution
A thermally conductive material comprising a hydrogenated copolymer and zinc oxide with acicular crystal parts, optionally with paraffin oil or a flame retardant, which maintains flexibility and thermal conductivity while ensuring electrical insulation and toughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If silicone grease is applied for heat dissipation in compact devices, then heat dissipation is achieved, but work efficiency is low and part contamination occurs due to grease squeezing out
Solution Approach 1:
The patent replaces permanent silicone grease with a disposable thermally conductive sheet that is discarded after single use. This eliminates the reliability issues of grease squeezing out and contaminating parts, while maintaining effective heat dissipation during the device's operational lifetime.
Solution Approach 2:
The patent changes the physical state from liquid grease to solid sheet material, and controls the thickness parameter (0.5-2.0 mm) to optimize both thermal conductivity and mechanical properties. This parameter optimization prevents material breaking during installation while ensuring adequate heat dissipation performance.
2Ease of operation
If silicone rubber-based thermally conductive sheet is used, then ease of handling is improved, but manufacturing cost increases due to expensive silicone resin and additional curing steps
Solution Approach 1:
The patent uses inexpensive thermoplastic resin instead of expensive silicone resin, and employs simple melting and molding without curing steps. The material is designed for single-use applications, eliminating the need for costly curing processes while maintaining adequate performance.
Solution Approach 2:
The patent changes the material class from silicone rubber to thermoplastic resin, which allows processing at lower temperatures and without curing. The melting point is controlled (80-150°C) to enable easy handling and molding while reducing manufacturing complexity and cost.
3Temperature
If silicone resin-based thermally conductive sheet is used, then thermal conductivity is improved, but contact failure occurs due to low molecular weight siloxane gas generation and silicon dioxide formation
Solution Approach 1:
The patent uses a disposable thermoplastic resin-based sheet that does not generate harmful gases during use. Since the material is discarded after single use, there is no opportunity for low molecular weight substances to migrate and cause contact failure, eliminating the harmful effects associated with silicone resin.
Solution Approach 2:
The patent converts the potential harm of material degradation into a benefit by choosing a material (thermoplastic resin) that does not degrade into harmful substances. The simple polymer structure of thermoplastic resin avoids the low molecular weight siloxane issue inherent in silicone resin, preventing contact failure.
4Length of stationary object
If thermally conductive sheet with thickness greater than 1 mm is used to bridge gaps, then gap filling is improved, but flexibility and toughness requirements increase to prevent material breaking
Solution Approach 1:
The patent optimizes the thickness parameter to 0.5-2.0 mm, which balances gap-filling capability with mechanical strength. This controlled thickness range ensures the sheet is thick enough to bridge gaps but thin enough to maintain flexibility and resist breaking during installation.
Solution Approach 2:
The patent uses composite materials combining thermoplastic resin with thermally conductive fillers (such as metal powders or ceramic particles). This composite structure provides both the mechanical flexibility needed for thin sheets and the thermal conductivity required for heat dissipation, while the thermoplastic matrix gives toughness to prevent breaking.
5Temperature
If thin aluminum film is used for floor heating, then thermal conductivity is improved, but cushioning is lacking resulting in poor proximity of pipes and floor
Solution Approach 1:
The patent uses composite materials combining thermoplastic resin with thermally conductive fillers to achieve both flexibility and thermal conductivity. The thermoplastic matrix provides cushioning and conformability to bridge gaps between pipes and floor, while the conductive filler ensures effective heat transfer.
Solution Approach 2:
The patent changes from thin metal film to a thicker polymer-based composite sheet (0.5-2.0 mm), which provides the necessary cushioning and flexibility. The material can deform to conform to irregular surfaces while maintaining adequate thermal conductivity through the conductive filler content.
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 solution achieves enhanced thermal conductivity and electrical insulation while maintaining flexibility and toughness, effectively addressing the limitations of existing materials in heat dissipation and compatibility with semiconductor elements.
Implementation Method 1
a thermally conductive material comprising: a hydrogenated copolymer (1) satisfying conditions (a) to (d) which is produced by hydrogenating a copolymer of a conjugated diene and a vinyl aromatic; and zinc oxide (3) comprising a core part and acicular crystal parts extending from the core part in four different axial directions
Implementation Method 2
a hydrogenated copolymer (1) satisfying the following conditions (a) to (d) which is produced by hydrogenating a copolymer of a conjugated diene and a vinyl aromatic
Data Source
AI summary
Disclosed is a thermally conductive material having excellent heat conductivity and insulating properties and having flame retardancy while retaining flexibility and toughness. More specifically, there is provided a thermally conductive material comprising: a hydrogenated copolymer (1) and/or a modified hydrogenated copolymer (2) in which each has a specific structure and is contained in a specific amount; and zinc oxide (3) comprising a core part and acicular crystal parts extending from the core part in four axial directions. The thermally conductive material optionally further comprises a paraffin oil (4), a flame retardant (5), or a filler (6) having a thermal conductivity of 10 to 400 W/m·K (the zinc oxide (3) is excluded).