Thermoplastic Resin Composition Thermal Conductivity Moldability

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Solution Overview

Problem

Existing thermoplastic resin compositions with PAN-based carbon fibers exhibit poor thermal conductivity, while those with high graphite content have poor moldability, and compositions lacking graphite show inadequate thermal conductivity in molded bodies.

Innovation Solution

A thermoplastic resin composition comprising a polyamide resin, pitch-based carbon fibers with a mass average fiber length of 0.1 mm to 0.3 mm, and graphite at a content rate of 1% to 20% by mass, which enhances thermal conductivity and mechanical properties in molded bodies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If PAN-based carbon fiber is used as the only carbon fiber, then the thermoplastic resin composition can be produced, but the molded body exhibits poor thermal conductivity

Engineering Contradiction:
Improvethermal conductivityVSAvoidmoldability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses a composite material system combining pitch-based carbon fiber and graphite particles within the thermoplastic resin. This composite approach leverages the high thermal conductivity of pitch-based carbon fiber (400-1500 W/mK) and the thermal conductive network formation capability of graphite particles to achieve superior thermal conductivity in the molded body, resolving the limitation of using PAN-based carbon fiber alone

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent specifies precise parameter ranges: pitch-based carbon fiber content at 30-70 mass%, graphite content at 1-20 mass%, and fiber length at 0.1-0.3 mm. These parameter optimizations balance thermal conductivity enhancement with moldability maintenance, allowing the resin composition to be properly filled and molded while achieving the desired thermal performance

Inventive Principle:
Principle #35Parameter changes

2Reliability

If high content rate of graphite is used, then thermal conductivity improves, but moldability deteriorates

Engineering Contradiction:
Improvethermal conductivityVSAvoidmoldability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent optimizes graphite content to 1-20 mass% (preferably 2-12 mass%) to achieve thermal conductivity improvement without excessive graphite accumulation that would harm moldability. This parameter optimization allows sufficient graphite particles to form thermal conductive networks while maintaining proper resin flow and filling characteristics during molding

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a synergistic composite system where pitch-based carbon fiber (30-70 mass%) provides the primary thermal conduction pathway with its high intrinsic conductivity (400-1500 W/mK), while graphite particles (1-20 mass%) supplement the thermal network. This composite structure reduces the reliance on high graphite content, thereby maintaining moldability while achieving excellent thermal conductivity

Inventive Principle:
Principle #40Composite materials

3Reliability

If pitch-based carbon fiber content is increased to improve thermal conductivity, then thermal conductivity improves, but the composition becomes difficult to mold

Engineering Contradiction:
Improvethermal conductivityVSAvoidmoldability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent optimizes pitch-based carbon fiber content to 30-70 mass% (preferably 35-65 mass%) and fiber length to 0.1-0.3 mm. This parameter optimization ensures sufficient thermal conductivity enhancement while preventing excessive fiber concentration that would increase viscosity and hinder mold filling. The controlled fiber length also improves processability

Inventive Principle:
Principle #35Parameter changes

4Reliability

If graphite is not included in the composition, then moldability is maintained, but thermal conductivity of the molded body is insufficient

Engineering Contradiction:
Improvethermal conductivityVSAvoidmoldability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs a dual-component reinforcement system combining pitch-based carbon fiber and graphite particles. The pitch-based carbon fiber provides the primary thermal conduction pathway with its high intrinsic conductivity, while the graphite particles (1-20 mass%) form additional thermal conductive networks and bridges, creating a synergistic effect that achieves superior thermal conductivity without compromising moldability

Inventive Principle:
Principle #40Composite materials

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 a thermal conductivity of 10 W/mK or more and a tensile strength of 100 MPa or more in molded bodies, improving both thermal conductivity and mechanical properties while maintaining moldability.

Implementation Method 1

a thermal conductivity of a molded body which is obtained by molding the thermoplastic resin composition and has a thickness of 1 mm measured by a hot wire method is 10 W/mK or more

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS11279808B2Thermoplastic resin composition, method for producing thermoplastic resin composition, and molded body
Publication Date: 2022.03.22 MITSUBISHI CHEM CORP

AI summary

Provided is a thermoplastic resin composition which provides a molded body having excellent thermal conductivity and excellent mechanical characteristics. A thermoplastic resin composition which contains (A) a thermoplastic resin, (B) pitch carbon fibers and (C) graphite, and wherein: the content of the graphite (C) is from 1% by mass to 20% by mass (inclusive) relative to 100% by mass of the thermoplastic resin composition; and a molded body, which is obtained by molding this thermoplastic resin composition and has a thickness of 1 mm, has a thermal conductivity of 10 W/mK or more as determined by a hot wire method.