Metal-Detectable Fluororubber Composition With Low Compression Set

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Solution Overview

Problem

Existing fluororubber compositions used in food production facilities fail to detect tiny rubber pieces and do not provide adequate compression set resistance, posing a risk of contamination and reduced product life.

Innovation Solution

A fluororubber composition compounded with triiron tetraoxide having a BET specific surface area of 4.0 m2/g or less at a ratio of 7.0 vol % or more, enabling detection by a metal detector and maintaining excellent compression set resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If fluororubber is compounded with metal oxide (black iron oxide), then detection by metal detector is improved, but compression set resistance deteriorates

Engineering Contradiction:
Improvedetection capabilityVSAvoidcompression set resistance
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the parameters of the metal oxide additive by specifying triiron tetraoxide with a BET specific surface area of 4.0 m2/g or less and a volume fraction of 7.0 vol% or more. This specific parameter combination resolves the contradiction by achieving both detection capability (improved by metal oxide presence) and compression set resistance (maintained by controlling surface area and concentration).

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite fluororubber material containing triiron tetraoxide particles distributed within the rubber matrix. This composite structure enables the material to simultaneously provide detection capability through the magnetic metal oxide particles and maintain compression set resistance through the fluororubber base material with optimized composition.

Inventive Principle:
Principle #40Composite materials

2Measurement precision

If metal oxide is added to fluororubber, then detectability of rubber pieces is improved, but product life is reduced

Engineering Contradiction:
ImprovedetectabilityVSAvoidproduct life
Core Design Contradiction:
Measurement precisionVSDuration of action of stationary object

Solution Approach 1:

The patent optimizes the parameters of metal oxide addition by specifying triiron tetraoxide with controlled BET specific surface area (4.0 m2/g or less) and volume fraction (7.0 vol% or more). This parameter optimization ensures sufficient detectability while maintaining the structural integrity and longevity of the fluororubber product.

Inventive Principle:
Principle #35Parameter changes

3Strength

If filler is used in rubber compounding, then mechanical properties are improved, but filler leakage occurs

Engineering Contradiction:
Improvemechanical propertiesVSAvoidfiller leakage
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent employs a composite fluororubber material containing triiron tetraoxide particles that are evenly distributed and firmly embedded in the rubber matrix. This composite structure provides enhanced mechanical properties while preventing filler leakage, as the particles remain contained within the cured rubber structure.

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 crosslinked product is detectable by a metal detector for pieces up to 1 mm and exhibits a compression set of 21% or less after 70 hours at 175°C, suitable for use in food production facilities.

Implementation Method 1

A crosslinked product obtained from the fluororubber composition according to the present invention can be detected by a metal detector even if it is tiny pieces

Methodology Applied
Scientific EffectMagnetic detection: Magnetism

Implementation Method 2

A crosslinked product obtained from the fluororubber composition according to the present invention

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Data Source

PatentUS20250346791A1Fluororubber composition
Publication Date: 2025.11.13 NOK CORP

AI summary

A fluororubber composition in which fluororubber is compounded with triiron tetraoxide having a BET specific surface area of 4.0 m2/g or less at a ratio of 7.0 vol % or more as a volume fraction. A crosslinked product obtained by the fluororubber composition according to the present invention can be detected 1 mm pieces thereof by using a metal detector ND-840, produced by Nissin Electronics Co., Ltd., under the detection sensitivity conditions (Fe: 0.6 in diameter, SUS: 1.5 in diameter). Further, the compression set of the crosslinked product using an O-ring at 175° C. after 70 hours is 21% or less, and thus the crosslinked product can be effectively used for gaskets, O-rings, and the like for food production facilities, food machinery, automobiles, etc.