Fluororubber Composition Using CNT Masterbatch for Wear-Resistant Seals

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Solution Overview

Problem

Fluororubber compositions used in high load environments face issues with abrasion resistance and blister resistance, particularly when carbon nanotubes are compounded with fluororubber polymers, leading to inferior roll kneading properties and rough rubber surfaces.

Innovation Solution

A fluororubber composition is developed using a kneaded mixture of a carbon nanotube masterbatch containing 4 to 20 parts by weight of multilayer carbon nanotubes, which are fibrous carbon nanostructures without monolayer carbon nanotubes, compounded with a fluororubber polymer at 0.5 to 6 wt.%, along with a reinforcing filler, to produce a crosslinked molded article with improved abrasion and blister resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If carbon nanotubes are compounded with fluororubber polymer to improve sealing properties, then abrasion resistance and blister resistance are improved, but roll kneading properties deteriorate and rubber surface becomes rough

Engineering Contradiction:
Improvesealing propertiesVSAvoidroll kneading properties
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent divides the carbon nanotube addition into two stages: first creating a masterbatch with high carbon nanotube concentration (4-20 parts by weight per 100 parts fluororubber polymer), then adding a smaller amount (0.5-6 wt.% in final mixture) to the fluororubber raw material. This segmentation allows controlled dispersion and maintains kneading properties while achieving desired sealing performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent specifies precise parameter ranges for carbon nanotube content (0.5-6 wt.% in kneaded mixture) and masterbatch composition (4-20 parts per 100 parts fluororubber polymer) to optimize both sealing properties and kneading characteristics. These parameter controls prevent surface roughness while maintaining abrasion and blister resistance.

Inventive Principle:
Principle #35Parameter changes

2Strength

If high amount of carbon nanotubes is compounded to enhance reinforcing properties, then tensile strength and breaking elongation increase, but kneading processability and surface quality deteriorate

Engineering Contradiction:
Improvetensile strengthVSAvoidkneading processability
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent segments carbon nanotube addition into masterbatch preparation and final compounding stages. The masterbatch contains 4-20 parts carbon nanotubes per 100 parts fluororubber polymer, but only 0.5-6 wt.% of this masterbatch is added to the final mixture, achieving strength enhancement without excessive nanotube content that would harm processability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The carbon nanotube masterbatch acts as an intermediary carrier that pre-disperses carbon nanotubes in a manageable concentration. This masterbatch then serves as a controlled addition source to the fluororubber raw material, ensuring uniform distribution and maintaining kneading processability while achieving desired tensile strength.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If carbon nanotubes are added to fluororubber to achieve blister resistance, then sealing reliability is improved, but rubber compound surface becomes rough

Engineering Contradiction:
Improveblister resistanceVSAvoidrubber compound surface quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent precisely controls carbon nanotube content at 0.5-6 wt.% in the kneaded mixture and specifies masterbatch composition (4-20 parts per 100 parts fluororubber polymer) to achieve optimal balance. This parameter control ensures blister resistance while preventing surface roughness that would occur with higher concentrations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

By segmenting the addition process into masterbatch preparation and controlled final compounding, the patent achieves uniform carbon nanotube distribution that provides blister resistance without creating surface roughness. The segmented approach allows precise control over final nanotube concentration and dispersion quality.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS11613612B2Fluororubber composition, method for producing the same and fluororubber crosslinked molded article
Publication Date: 2023.03.28 NOK CORP

AI summary

A fluororubber composition that is a kneaded mixture of a carbon nanotube masterbatch comprising 4 to 20 parts by weight of multilayer carbon nanotubes, which are fibrous carbon nanostructures that do not contain monolayer carbon nanotubes, based on 100 parts by weight of a fluororubber polymer, and a fluororubber raw material comprising at least a fluororubber polymer and a reinforcing filler, in which the multilayer carbon nanotubes are compounded in an amount of 0.5 to 6 wt. % in the kneaded mixture. The kneading is performed using a roll or a kneader when the fluororubber composition is produced. The fluororubber composition can provide a fluororubber crosslinked molded article that exhibits abrasion resistance and blister resistance.