Polysiloxane Coating for Wiring Board Heat Dissipation

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Solution Overview

Problem

Wiring boards with heat-dissipating ceramic layers made from water-soluble clay suffer from poor adhesion to metal substrates due to hygroscopicity, leading to short-term heat dissipation effectiveness.

Innovation Solution

A method involving a polysiloxane structure and inorganic particles with insulating and heat-dissipating properties is applied to the metal substrate, cured through condensation, providing a stable and adherent layer that maintains heat dissipation over long periods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a water-soluble clay is applied to form a heat-dissipating ceramic layer, then heat dissipation capability is improved, but adhesion to metal substrate deteriorates due to high hygroscopicity

Engineering Contradiction:

Improveheat dissipation capabilityVSAvoidadhesion to substrate

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

An organic solvent is introduced as an intermediary substance to replace water in the clay composition. This intermediary prevents the hygroscopicity problem while maintaining the heat dissipation function, resolving the contradiction between heat dissipation capability and adhesion reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The chemical composition parameter of the clay slurry is changed by substituting water with organic solvent. This parameter change eliminates the hygroscopicity issue that causes poor adhesion, while preserving the thermal conductivity properties needed for heat dissipation.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If the ceramic layer is made from water-soluble clay, then manufacturing ease is improved, but durability over time deteriorates due to falling off substrate

Engineering Contradiction:

Improveapplication process simplicityVSAvoidlong-term durability

Core Design Contradiction:

Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The organic solvent acts as a intermediary that maintains the slurry's applicability while preventing long-term durability issues. It allows easy application like water-based slurries but prevents the material from detaching over time by eliminating hygroscopicity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent avoids using water-soluble clay that would require frequent replacement due to detachment. By using organic solvent-based clay, the coating becomes a long-lasting solution that maintains adhesion throughout the product lifecycle.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Temperature

If inorganic particles with high thermal conductivity are used, then heat dissipation is improved, but adhesion to substrate deteriorates due to hygroscopicity

Engineering Contradiction:

Improveheat dissipation efficiencyVSAvoidbonding strength

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The organic solvent serves as a intermediary medium that allows inorganic particles to be suspended and applied effectively while preventing hygroscopicity. This maintains both the heat dissipation efficiency from the inorganic particles and the bonding strength to the substrate.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a composite material system combining inorganic particles (for heat dissipation) with organic solvent-based binder (for adhesion). This composite approach allows both thermal performance and bonding reliability to be optimized simultaneously.

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 solution ensures a wiring board with sustained heat dissipation capabilities, enhanced adhesion, and resistance to ultraviolet deterioration, maintaining performance under harsh conditions.

Implementation Method 1

the curing results from condensation by dehydration or dealcoholization

Methodology Applied

Scientific EffectCondensation by dehydration: Condensation

Implementation Method 2

the curing results from condensation by dehydration or dealcoholization

Methodology Applied

Scientific EffectCondensation by dealcoholization: Condensation

Implementation Method 3

The term 'heat-dissipating properties' refers to the nature of a substance which absorbs heat from the wiring parts of a wiring board with which the substance is in contact, and releases the heat to other parts or the atmosphere

Methodology Applied

Scientific EffectHeat dissipation: Conduction (thermal)

Data Source

PatentEP2230889B1Method for producing wiring board and wiring board

Publication Date: 2020.04.22 ASAHI RUBBER

Figure 1(A)~1(D)

AI summary

The present invention provides a wiring board giving good heat dissipation over a long period of use. The present invention also provides a method for producing a wiring board, including coating a surface of a metal substrate 2, which is made of an aluminium plate, with a composition 3 containing a substance having a polysiloxane structure and inorganic particles having insulating and heat-dissipating properties (Fig. 1(B)), curing the composition 3, then bonding a copper foil 4 to the cured composition 3A (Fig. 1(C)), and partially removing the copper foil 4, thereby forming a wiring layer 5 (Fig. 1(D)).