Self-Sealing Elastomer Composition for Pneumatic Tires
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing self-sealing compositions for pneumatic tires face challenges in stability and effectiveness across a wide range of temperatures and have drawbacks such as high hysteresis, increased rolling resistance, and difficulties in manufacturing and use, particularly due to the use of butyl rubbers and high levels of hydrocarbon resin.
Innovation Solution
A self-sealing composition based on a blend of polybutadiene and natural rubber or synthetic polyisoprene elastomers, with a hydrocarbon resin and minimal filler, which provides improved anti-puncture performance without the need for butyl rubber or significant hydrocarbon resin, maintaining effectiveness at low temperatures and reducing rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If butyl rubber is used as the base elastomer for self-sealing composition, then sealing effectiveness is improved, but hysteresis losses increase and rolling resistance increases
Solution Approach 1:
The patent changes the chemical composition parameters by replacing butyl rubber with a blend of polybutadiene and natural rubber or synthetic polyisoprene. This parameter change maintains the self-sealing function while reducing hysteresis losses and rolling resistance, as the new elastomer blend has lower tan δ values across the temperature spectrum compared to butyl rubber.
Solution Approach 2:
The patent uses a composite elastomer system combining polybutadiene with natural rubber or synthetic polyisoprene in specific ratios. This composite approach achieves the self-sealing effect through the synergistic interaction of the elastomers and the hydrocarbon resin, while avoiding the high hysteresis inherent in pure butyl rubber compositions.
2Reliability
If high levels of hydrocarbon resin are used in self-sealing composition, then anti-puncture performance is improved, but manufacturing complexity increases and mixing time increases
Solution Approach 1:
The patent optimizes the hydrocarbon resin content to a specific range (30-90 phr) and selects resins with Tg greater than 0°C, changing the compositional parameters to achieve effective anti-puncture performance while maintaining manageable manufacturing characteristics. This controlled parameter approach reduces mixing complexity compared to formulations requiring extreme resin levels.
3Ease of operation
If liquid elastomer is used in self-sealing composition, then fluidity is improved for sealing, but creep risk increases at high temperatures
Solution Approach 1:
The patent changes the physical state parameter of the elastomer from liquid to solid form. By using solid elastomers (polybutadiene blended with natural rubber or synthetic polyisoprene) instead of liquid elastomer, the composition maintains adequate fluidity for sealing through the plasticizing effect of hydrocarbon resin while eliminating the creep risk associated with liquid elastomers at elevated temperatures.
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 seals punctures in pneumatic tires across a wide temperature range with reduced rolling resistance and improved mechanical strength, enhancing the tire's performance and durability.
Implementation Method 1
Self-sealing compositions capable of achieving such an objective, by definition capable of automatically ensuring, that is to say without any external intervention, the sealing of a pneumatic tire in the event of perforation
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a self-sealing elastomer composition which can be used in particular as an anti-puncture layer in a pneumatic object, based on at least ("phe" meaning parts by weight per hundred parts of solid elastomer): a blend of at least two solid elastomers, namely a polybutadiene elastomer or butadiene copolymer, referred to as "elastomer A", and a natural rubber elastomer or synthetic polyisoprene, referred to as "elastomer B", the elastomer A : elastomer B weight ratio being in the range of 10:90 to 90:10; between 30 and 90 phe hydrocarbon resin; and 0 to less than 120 phe filler, with 0 to less than 30 phe reinforcing filler. The invention also relates to a pneumatic object such as a pneumatic tyre provided with an anti-puncture layer comprising a composition of the invention. The anti-puncture layer is advantageously associated with an airtight layer, for example based on butyl rubber or TPS elastomer, in order to form an airtight, anti-puncture laminate in the pneumatic object.