Pneumatic Tire Innerliner Insulation Adhesion
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Solution Overview
Problem
Pneumatic tires with high butyl-based rubber content for improved air retention exhibit poor vulcanized adhesion to other rubber compounds, leading to peeling issues, especially at the joint portion during the tire building process.
Innovation Solution
A pneumatic tire design incorporating an innerliner rubber composition with 80-100% butyl-based rubber, 40-70 parts carbon black, 0.5-5.0 parts zinc oxide, and 0.2-5.0 parts sulfur, and an insulation rubber composition with 20-90% butyl-based rubber, 10-80% isoprene-based rubber, 40-80 parts carbon black, and 0.2-5.0 parts sulfur, where the butyl-based rubber content in the innerliner exceeds or equals that in the insulation, enhancing adhesion and air retention properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the butyl-based rubber content in the innerliner is increased to improve air retention properties, then air retention improves, but vulcanized adhesion to the insulation deteriorates, causing peeling at the interface
Solution Approach 1:
The invention changes the chemical composition parameters of the rubber compounds by introducing specific additives (zinc oxide in innerliner, sulfur in both layers) and controlling the ratio of butyl-based rubber to other components. This allows achieving both high air retention (80-100% butyl-based rubber) and adequate adhesion through chemical modification of the rubber composition rather than reducing the butyl-based rubber content
Solution Approach 2:
The invention uses zinc oxide and sulfur as intermediary substances that facilitate adhesion between the high-butyl innerliner and the insulation. These additives act as chemical mediators that enable vulcanized bonding at the interface, allowing the high-butyl composition to maintain both air retention and adhesion properties simultaneously
2Strength
If a butyl tape is attached to the joint portion to improve adhesion, then adhesion at the joint portion improves, but peeling may still occur in portions other than the joint portion, and the solution is insufficient
Solution Approach 1:
The invention makes the rubber composition itself universally effective throughout the entire innerliner and insulation structure, rather than applying a localized patch (butyl tape) only at the joint portion. The chemical composition modification applies globally across all components, providing comprehensive adhesion protection throughout the entire tire structure, not just at specific weak points
Solution Approach 2:
The invention incorporates adhesion-enhancing additives (zinc oxide, sulfur) into the rubber composition during manufacturing, before the tire is assembled and put into service. This preliminary chemical preparation ensures that the adhesion capability is built into the material structure itself, rather than attempting to address adhesion issues after peeling has begun to occur during tire operation
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 tire achieves excellent air retention and adhesion at the interface between the innerliner and insulation, particularly in the joint portion, reducing peeling and maintaining internal pressure effectively.
Implementation Method 1
Innerliners are tire components that provide air retention properties by reducing air leakage (air permeation) from inside to outside of the tire. These components contain butyl-based rubbers having low air permeability
Implementation Method 2
the innerliner rubber composition containing a polymer component including, based on 100% by mass thereof, 80 to 100% by mass of a butyl-based rubber and containing, per 100 parts by mass of the polymer component, 40 to 70 parts by mass of carbon black, 0.5 to 5.0 parts by mass of zinc oxide, and 0.2 to 5.0 parts by mass of sulfur
Data Source
Figure 1
AI summary
Provide is a pneumatic tire that is excellent in air retention properties and adhesion at the interface between the innerliner and the insulation, particularly in the joint portion. Included is a pneumatic tire including: a carcass; an insulation adjacent to the radially inner side of the carcass; and an innerliner adjacent to the radially inner side of the insulation, the innerliner including an innerliner rubber composition, the innerliner rubber composition containing a polymer component including, based on 100% by mass thereof, 80 to 100% by mass of a butyl-based rubber and containing, per 100 parts by mass of the polymer component, 40 to 70 parts by mass of carbon black, 0.5 to 5.0 parts by mass of zinc oxide, and 0.2 to 5.0 parts by mass of sulfur, the insulation including an insulation rubber composition, the insulation rubber composition containing a polymer component including, based on 100% by mass thereof, 20 to 90% by mass of a butyl-based rubber and 10 to 80% by mass of an isoprene-based rubber and containing, per 100 parts by mass of the polymer component, 40 to 80 parts by mass of carbon black and 0.2 to 5.0 parts by mass of sulfur, the innerliner and insulation rubber compositions having butyl-based rubber contents based on 100% by mass of the polymer component that satisfy the following relationship: Butyl-basedrubbercontentofinnerlinerrubbercompositionâ„Butyl-basedrubbercontentofinsulationrubbercomposition.