Thermoplastic Resin Composition for High Thermal Conductivity and Weld Strength

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Solution Overview

Problem

Conventional methods fail to produce a thermoplastic resin composition that balances high thermal conductivity with excellent weld strength, especially when filled with a large amount of filler, due to limitations in filler types and processing complexities.

Innovation Solution

A thermoplastic resin composition comprising a thermoplastic polyester resin with a weight average molecular weight of 50,000 to 200,000, a polyalkylene terephthalate block copolymer, and a highly thermally conductive inorganic compound, such as graphite or aluminum nitride, which enhances both thermal conductivity and weld strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a large amount of highly thermally conductive inorganic filler is mixed with thermoplastic resin to increase thermal conductivity, then thermal conductivity is improved, but weld strength becomes extremely low

Engineering Contradiction:

Improvethermal conductivityVSAvoidweld strength

Core Design Contradiction:

TemperatureVSStrength

Solution Approach 1:

A graft copolymer serving as a coupling agent is introduced as an intermediary between the inorganic filler particles and the thermoplastic resin matrix. This coupling agent chemically bonds to both the filler surface and the resin, creating a bridge that transfers stress effectively and maintains weld strength even at high filler loadings (50-90 wt%) that would otherwise cause extreme brittleness

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention creates a multi-phase composite material system consisting of thermoplastic resin, high-volume inorganic filler (50-90 wt%), and graft copolymer coupling agent. This composite structure allows the filler to provide thermal conductivity while the coupling agent maintains interfacial adhesion, achieving both high thermal conductivity (0.3-1.5 W/m·K) and acceptable weld strength simultaneously

Inventive Principle:

Principle #40Composite materials

2Strength

If glass fiber with controlled aspect ratio is used to increase weld strength, then weld strength is improved, but the filler type is limited and cannot be filled with a large amount of another filler

Engineering Contradiction:

Improveweld strengthVSAvoidfiller type flexibility

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The graft copolymer coupling agent provides universal compatibility with multiple types of inorganic fillers including metal oxides (alumina, aluminum nitride, magnesium oxide), carbon-based fillers (graphite, carbon fiber), and other ceramics. This single coupling mechanism allows versatile filler selection based on thermal conductivity requirements without being restricted to specific filler types as would be the case with glass fiber reinforcement

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Temperature

If a thermoplastic resin is filled with a large amount of filler to achieve high thermal conductivity, then thermal conductivity is improved, but moldability deteriorates

Engineering Contradiction:

Improvethermal conductivityVSAvoidmoldability

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The graft copolymer coupling agent modifies the interfacial parameters between filler and resin, reducing friction and improving stress transfer. This allows the use of very high filler volumes (50-90 wt%) without the severe moldability deterioration that would normally occur, enabling injection molding of complex shapes even with such high filler loadings that would typically make processing impossible

Inventive Principle:

Principle #35Parameter changes

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 high thermal conductivity and strong weld portions even when filled with a large amount of filler, improving moldability and thermal durability while maintaining mechanical strength.

Implementation Method 1

a polyalkylene terephthalate block copolymer composed of a polyether segment and a polyethylene terephthalate segment which includes an ethylene terephthalate unit as a main component

Methodology Applied

Scientific EffectPhonon transport:

Implementation Method 2

at least one kind of highly thermally conductive inorganic compound selected from the group consisting of graphite, electrically conductive metal powder, soft magnetic ferrite, carbon fiber, electrically conductive metal fiber, zinc oxide, boron nitride, aluminum nitride, silicon nitride, aluminum oxide, magnesium oxide, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, beryllium oxide, and diamond

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS10030138B2High thermal conductivity thermoplastic resin composition with excellent injection moldability

Publication Date: 2018.07.24 KANEKA CORP

AI summary

A highly thermally conductive thermoplastic resin composition of the present invention contains: (A) a thermoplastic polyester resin having a weight average molecular weight of 50,000 to 200,000; (B) a polyalkylene terephthalate block copolymer composed of a polyether segment and a polyethylene terephthalate segment which includes an ethylene terephthalate unit as a main component; and (C) a highly thermally conductive inorganic compound, the highly thermally conductive thermoplastic resin composition containing, with respect to 100 parts by weight of (A) the thermoplastic polyester resin, 20 parts by weight to 200 parts by weight of (B) the polyalkylene terephthalate block copolymer and 20 parts by weight to 250 parts by weight of (C) the highly thermally conductive inorganic compound.