Protected Negative-Expansion Resin Composition for Stable Molding

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Solution Overview

Problem

Existing resin compositions with negative thermal expansion materials face issues of high production costs due to the use of rare elements and unstable supply, and functional deterioration during processing with thermoplastic resins, leading to insufficient thermal expansion suppression.

Innovation Solution

A resin composition incorporating metal oxide particles with a negative thermal expansion property, coated with a protective layer containing Si, Al, or Ti, which suppresses electron transfer and maintains thermal stability during processing, combined with a thermoplastic resin to achieve balanced thermal expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal oxide particles with negative thermal expansion property are added to thermoplastic resin, then thermal expansion suppression is improved, but functional deterioration occurs during melt extrusion or injection molding processing

Engineering Contradiction:

Improvethermal expansion suppressionVSAvoidfunctional deterioration during processing

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

A protective layer is formed on the surface of the metal oxide particles before blending with the thermoplastic resin. This preliminary protective coating prevents electron transfer and functional deterioration during subsequent melt extrusion or injection molding processing, while maintaining the negative thermal expansion property.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The protective layer acts as an intermediary between the metal oxide particles and the thermoplastic resin matrix. It prevents harmful electron transfer during processing while allowing the metal oxide particles to maintain their negative thermal expansion function, thus mediating between the processing requirements and the functional requirements.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If rare metal elements are used to achieve negative thermal expansion property, then thermal expansion suppression is improved, but production cost increases and supply stability deteriorates

Engineering Contradiction:

Improvethermal expansion suppressionVSAvoidproduction cost and supply stability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive rare metal elements with more economical metal oxide particles that can be readily obtained. While the individual particles may have limited stability during processing, the protective layer compensates for this, making the overall system both cost-effective and functionally stable.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention changes the material parameters by selecting metal oxide particles with specific properties (negative thermal expansion coefficient) and applying a protective layer, rather than relying on rare metal elements. This parameter change achieves the desired thermal expansion suppression while improving cost-effectiveness and supply stability.

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 effectively suppresses thermal expansion in thermoplastic resins, maintaining mechanical properties and optical accuracy in molded bodies, suitable for precision equipment.

Implementation Method 1

metal oxide particles with a negative coefficient of linear expansion at 0° C. to 60° C. (hereinafter also referred to as 'negative thermal expansion metal oxide particles')

Methodology Applied

Scientific EffectNegative thermal expansion: Negative Thermal Expansion

Implementation Method 2

a surface of the metal oxide particles is provided with a compound containing at least one metal element selected from Si, Al, and Ti

Methodology Applied

Scientific EffectElectron transfer suppression:

Data Source

PatentUS12479972B2Resin composition and resin molded body thereof

Publication Date: 2025.11.25 CANON KK

AI summary

The present invention aims to obtain a resin composition with low thermal expansion property by suppressing functional deterioration in negative thermal expansion property when a negative thermal expansion material is added to a thermoplastic resin and heat-processed. The present invention provides a resin composition including metal oxide particles and a thermoplastic resin, both having a negative thermal expansion property. The negative thermal expansion of the particles is attributed to a crystal phase transition, which is driven by electron transfer between the constituent metals, and a covalent protective layer that inhibits the electron transfer is formed between the particles and the thermoplastic resin.