Polyamide Resin Thermal Conductivity via Graphite Fiber Composite
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Solution Overview
Problem
Current polyamide resin compositions face challenges in achieving high thermal conduction and mechanical properties without using carbon fibers with thermal conductivity above 100 W/mK, while maintaining productivity and preventing degradation of electrical insulating properties under high-temperature and high-humidity conditions, and ensuring uniform thermal conductivity in molded articles.
Innovation Solution
A polyamide resin composition comprising 50 to 100 parts by volume of flake graphite, 5 to 40 parts by volume of PAN carbon fibers, and 0.1 to 5 parts by volume of polyhydric alcohol, along with specific metal oxide particles, which are melt-kneaded to produce a stable and uniform thermal conductivity without opening the extruder head, ensuring excellent mechanical and electrical insulating properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If graphite is incorporated into thermoplastic resin to improve thermal conduction properties, then thermal conduction properties are improved, but the proportion of melted resin is reduced making it difficult to maintain high productivity
Solution Approach 1:
The patent combines flake graphite with PAN carbon fibers to create a composite filler system that achieves superior thermal conduction properties (10 W/mK or more) while maintaining resin meltability and productivity, resolving the contradiction between thermal performance and manufacturing efficiency
2Temperature
If carbon fibers with thermal conductivity of 100 W/mK or more are incorporated to improve thermal conduction properties, then thermal conduction properties are improved, but mechanical strength and electrical insulating properties deteriorate
Solution Approach 1:
The patent uses a composite filler system of flake graphite and PAN carbon fibers that achieves thermal conduction of 10 W/mK or more while maintaining electrical insulating properties and mechanical strength, avoiding the need for high-conductivity carbon fibers that compromise reliability
3Temperature
If magnesium oxide is incorporated to improve thermal conduction properties, then thermal conduction properties are improved, but the proportion of melted resin is reduced making it difficult to maintain high productivity
Solution Approach 1:
The patent replaces magnesium oxide with a flake graphite-PAN carbon fiber composite that provides comparable or superior thermal conduction while maintaining resin meltability and high productivity in extrusion processes
4Temperature
If flake graphite is incorporated to improve thermal conduction properties, then thermal conduction properties are improved, but thermal conductivity varies depending on location of measurement
Solution Approach 1:
The patent combines flake graphite with PAN carbon fibers to create a composite filler system that achieves uniform thermal conductivity distribution throughout the molded article, eliminating location-dependent variations while maintaining high thermal conduction properties
Solution Approach 2:
The patent optimizes the ratio of flake graphite to PAN carbon fibers and controls particle size distributions to achieve uniform thermal conductivity throughout the molded article, ensuring consistent thermal performance regardless of measurement location
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 excellent mechanical and electrical insulating properties with uniform thermal conductivity, even after high-temperature and high-humidity treatment, and allows for stable production using a general kneader, enhancing the performance of polyamide resin in electronic devices.
Implementation Method 1
a polyhydric alcohol (D), relative to 100 parts by volume of the polyamide resin (A)... which is obtainable by melt-kneading
Implementation Method 2
the thermal conduction properties of the resin are improved according to the amount of the graphite incorporated... 50 to less than 100 parts by volume of flake graphite (B), 5 to less than 40 parts by volume of carbon fibers (C)
Data Source
Figure 1
AI summary
(1) A polyamide resin composition comprising, relative to 100 parts by volume of a polyamide resin, 50 to less than 100 parts by volume of flake graphite, 5 to 40 parts by volume of carbon fibers, and 0.1 to 5 parts by volume of a polyhydric alcohol; (2) a polyamide resin composition comprising a polyamide resin and, as a property imparting component, at least one member selected from the group consisting of a metal oxide, a nitrogen compound, and a silicon compound, wherein the dicarboxylic acid units of the polyamide resin are oxalic acid in an amount of 70 mol% or more, based on the total dicarboxylic acid units; or (3) a polyamide resin composition comprising a polyamide resin and metal oxide particles, wherein the polyamide resin composition contains the metal oxide particles in an amount of 70 to 85% by mass, based on the mass of the polyamide resin composition, wherein the metal oxide particles contain those having a particle size of 70 µm or more in an amount of 10 to 50% by mass and those having a particle size of 20 µm or less in an amount of 1 to 50% by mass, based on the total mass of the metal oxide particles.