Self-Sealing Elastomer Composition Using Hot Compounding
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Solution Overview
Problem
Current self-sealing compositions for tires face challenges in manufacturing due to high resin content, which affects hysteresis, rolling resistance, and cohesion, leading to issues like creep at high temperatures and undesirable adhesive bonding to equipment.
Innovation Solution
A process involving a blend of polybutadiene and natural rubber elastomers with a hydrocarbon resin, using a masterbatch prepared at a hot compounding temperature, and incorporating a crosslinking agent, which eliminates the need for liquid plasticizers and reduces manufacturing difficulties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high content of hydrocarbon resin is used to achieve self-sealing property, then sealing effectiveness is improved, but hysteresis increases and rolling resistance worsens
Solution Approach 1:
The patent changes the physical state parameter of the elastomer from liquid to solid, while maintaining the resin content for self-sealing effectiveness. This parameter change allows achieving sealing reliability without the excessive energy loss associated with liquid elastomer formulations.
Solution Approach 2:
The patent uses a composite formulation combining solid elastomer with hydrocarbon resin and filler. This composite structure provides both the self-sealing property (from resin) and reduced hysteresis (from solid elastomer and filler), resolving the contradiction between sealing effectiveness and rolling resistance.
2Reliability
If high content of hydrocarbon resin is used to achieve self-sealing property, then sealing effectiveness is improved, but manufacturing complexity increases due to lengthy kneading
Solution Approach 1:
Changing the elastomer to solid state and optimizing the resin content range (50-90 parts per 100 parts elastomer) simplifies the kneading process. The solid elastomer provides better processability during mixing while maintaining self-sealing effectiveness, reducing manufacturing complexity.
3Ease of manufacture
If liquid elastomer is used to improve fluidity of composition, then processability is improved, but creep risk increases at high temperature
Solution Approach 1:
The patent changes the elastomer from liquid to solid state, fundamentally altering the temperature-stability profile. Solid elastomer provides inherent creep resistance at high temperatures while maintaining adequate processability during manufacturing through controlled mixing conditions.
4Stability of the object's composition
If filler such as carbon black is added to improve cohesion, then compositional stability is improved, but adhesive bonding to equipment increases undesirably
Solution Approach 1:
The patent applies local quality by using minimal filler (0-30 parts per 100 parts elastomer) specifically to provide cohesion where needed, while keeping the overall formulation low in filling agents to prevent excessive adhesion to equipment. The resin content is optimized to provide localized tackiness for self-sealing without causing equipment bonding issues.
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 process results in a high-performance self-sealing composition that maintains airtightness over a wide temperature range with reduced rolling resistance and improved cohesion, preventing excessive creep and adhesive issues.
Implementation Method 1
high-performance self-sealing compositions, based on natural rubber and on hydrocarbon resin as tackifying agent (tackifier)
Implementation Method 2
incorporating a crosslinking agent, which eliminates the need for liquid plasticizers and reduces manufacturing difficulties
Data Source
AI summary
Process for the manufacture of an elastomer composition having a self-sealing property which is based on at least (phr meaning parts by weight per 100 parts of solid elastomer): a blend of at least two solid elastomers, a polybutadiene or butadiene copolymer elastomer, referred to as “elastomer A”, and a natural rubber or synthetic polyisoprene elastomer, referred to as “elastomer B”, the elastomer A:elastomer B ratio by weight being within a range from 10:90 to 90:10; between 30 and 90 phr of a hydrocarbon resin; from 0 to less than 30 phr of filler, in which, during a first stage or stage (a), a masterbatch comprising at least the elastomers A and B and between 30 and 90 phr of a hydrocarbon resin is prepared by mixing these various components in a mixer at a “hot compounding” temperature or up to a “hot compounding” temperature which is greater than the softening temperature of the hydrocarbon resin.