Silica Insulating Composition for Stable Dielectric Breakdown Resistance

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Solution Overview

Problem

The challenge is to develop an insulating composition with silica particles that minimizes the elution of sodium ions, which can deteriorate the insulating properties of resin-based materials used in electronic and electrical components, especially under conditions of miniaturization where dielectric breakdown resistance and tracking resistance are critical.

Innovation Solution

The composition includes silica particles treated to reduce sodium ion elution by adjusting the pH, using cation exchange, and coating with silane compounds, ensuring the silica particles have a low Na ion content and a specific surface layer structure, thereby maintaining the insulating properties over time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If silica particles are incorporated into insulating resin to improve mechanical strength and chemical resistance, then the mechanical and chemical properties of the resin are improved, but sodium ion elution occurs which deteriorates electrical properties such as dielectric breakdown resistance and tracking resistance

Engineering Contradiction:
Improvemechanical strengthVSAvoiddielectric breakdown resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

A silane coating layer is applied as an intermediary between the silica particles and the resin matrix. This coating layer acts as a barrier that prevents sodium ions from eluting into the resin while maintaining the mechanical strength enhancement provided by the silica particles. The silane coating specifically targets and resolves the harmful sodium ion elution without compromising the beneficial mechanical properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The surface chemistry of silica particles is modified by coating with silane compounds, changing the surface parameters to reduce sodium ion content. This parameter change in the silica particle surface composition prevents sodium ion elution while preserving the mechanical reinforcement function of the silica particles in the insulating resin.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If additives such as glass fiber, colorants, or flame retardants are incorporated into insulating resin to improve specific properties, then those specific properties are improved, but electrical properties deteriorate due to additive incorporation

Engineering Contradiction:
Improvefunctional propertiesVSAvoidelectrical properties
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The silane coating is applied locally to the surface of silica particles, creating a localized protective layer that prevents sodium ion elution at the particle-resin interface. This local treatment allows the bulk silica particles to maintain their mechanical reinforcement function while the surface coating prevents electrical property deterioration.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The silane coating serves as an intermediary layer between the silica particles and the resin, preventing direct interaction that would cause sodium ion elution. This intermediary layer allows the silica particles to provide mechanical strength while preventing the harmful electrical property deterioration.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Duration of action of stationary object

If the insulating composition is exposed to environmental conditions over time, then the composition undergoes aging, but sodium ion elution increases which causes deterioration of insulating properties

Engineering Contradiction:
Improveservice lifeVSAvoidinsulating property stability
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The silane coating is applied in advance to silica particles before they are incorporated into the insulating resin. This preliminary protective layer prevents sodium ion elution during subsequent aging and environmental exposure, maintaining insulating properties throughout the service life of the composition.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The silane coating provides beforehand protection against sodium ion elution that would occur during aging. This prior cushioning measure ensures that even under environmental stress and prolonged service conditions, the insulating properties remain stable by preventing sodium ion release from silica particles.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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

This approach effectively reduces sodium ion elution from silica particles, enhancing the dielectric breakdown resistance and stability of the insulating composition, ensuring consistent performance even under increased voltage and environmental exposure.

Implementation Method 1

using cation exchange

Methodology Applied
Scientific EffectCation exchange: Ion Exchange

Implementation Method 2

coating with silane compounds

Methodology Applied
Scientific EffectHydrolysis: Hydrolysis

Implementation Method 3

coating with silane compounds

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP3680918B1Silica-containing insulating composition
Publication Date: 2023.12.27 NISSAN CHEM CORP
  • EP3680918B1 patent drawingFigure 1~2
  • EP3680918B1 patent drawingFigure 3~4
  • EP3680918B1 patent drawingFigure 5

AI summary

There is provided an insulating composition containing silica particles, a resin, and a curing agent, wherein elution of Na ions from the silica particles is prevented or reduced, and the composition undergoes a small change in insulating property over time. An insulating composition comprising silica particles (A), a resin (B), and a curing agent (C), wherein: when an aqueous solution of the silica particles (A) having an SiO2 concentration of 3.8% by mass is heated at 121°C for 20 hours, the amount of Na ions eluted from the silica particles (A) is 40 ppm/SiO2 or less, Especially, wherein the amount of Na ions eluted from the silica particles (A) after the heating may be 5 to 38 ppm/SiO2, and further, the silica particles (A) may contain a polyvalent metal oxide such that the ratio by mole of a polyvalent metal M to Si is 0.001 to 0.02; the mass ratio of Na2O/SiO2 in the silica particles may be 700 to 1,300 ppm; and the silica particles may have, on the surfaces thereof, a layer having a thickness of 0.1 to 1.5 nm and an Na2O/SiO2 mass ratio of 10 to 400 ppm, and may have an average particle diameter of 5 to 40 nm.