Tire Sealant Composition Balancing Sealability and Storage Flow

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Solution Overview

Problem

Existing sealant compositions for pneumatic tires face issues with sealability against through-holes, viscosity temperature dependency, and fluidity during storage and travel, which are not adequately addressed by current technologies.

Innovation Solution

A sealant composition is developed by blending specific amounts of a tackifier and a plasticizer with a rubber component, optimizing the blend ratio to enhance sealability, reduce viscosity temperature dependency, and inhibit flow due to heat or centrifugal forces, while maintaining reduced adhesive force for improved workability and contamination resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sealant composition is designed to flow easily into through-holes to improve sealability, then the sealability is improved, but the composition may flow excessively during storage or travel due to heat or centrifugal forces

Engineering Contradiction:
ImprovesealabilityVSAvoidfluidity stability during storage
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by carefully controlling the glass transition temperature (Tg) of the plasticizer within a specific range of -50°C to -20°C, and adjusting the plasticizer content to 5-60 phr. This parameter optimization allows the sealant to have appropriate fluidity at operating temperatures for sealing while maintaining stability during storage and travel, preventing excessive flow due to heat or centrifugal forces.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the viscosity temperature dependency of the sealant composition is reduced to improve sealability, then the sealability is improved, but the composition may lose its ability to maintain shape and resist flow during travel

Engineering Contradiction:
ImprovesealabilityVSAvoidresistance to centrifugal force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent uses composite materials by combining specific elastomers (unsaturated diene elastomer, nitrile rubber, butyl rubber) with plasticizers and fillers in optimized proportions. This composite formulation achieves reduced viscosity temperature dependency for improved sealability while maintaining sufficient structural integrity to resist centrifugal forces during travel. The synergistic interaction between components provides both fluidity for sealing and strength for withstanding operational forces.

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If the adhesive force of the sealant composition is reduced to improve workability and contamination resistance, then the ease of operation is improved, but the sealability against through-holes may be compromised

Engineering Contradiction:
ImproveworkabilityVSAvoidsealability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies parameter changes by optimizing the plasticizer content within a specific range of 5-60 phr and controlling the glass transition temperature of the plasticizer between -50°C and -20°C. This parameter optimization achieves the right balance: reduced adhesive force for improved workability and contamination resistance, while maintaining sufficient sealability against through-holes through appropriate fluidity and sealing mechanism.

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 optimized sealant composition effectively flows into through-holes to maintain air pressure, exhibits improved sealability and reduced viscosity temperature dependency, and prevents flow during storage and travel, while maintaining low adhesive force for better workability and contamination resistance.

Implementation Method 1

the sealant composition easily flows into through-holes formed in the tread portion to increase sealability

Methodology Applied
Scientific EffectViscosity flow:

Implementation Method 2

a liquid plasticizer having a glass transition temperature (Tg) of lower than −20° C.

Methodology Applied
Scientific EffectGlass transition:

Implementation Method 3

the sealant composition can be prevented from flowing due to the influence of heat or centrifugal forces applied during travel

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentUS20240247134A1Sealant composition and tire using the same
Publication Date: 2024.07.25 THE YOKOHAMA RUBBER CO LTD

AI summary

A sealant composition of the present invention is formed by blending, per 100 parts by mass of a rubber component (A), less than 30 parts by mass of a tackifier (B) and 20 parts by mass or more of a plasticizer (C), and thus the sealant composition can provide improved sealability, viscosity temperature dependency, and fluidity during storage of a tire.