Post-Cure Tire Sealant Layer for Puncture Sealing
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Solution Overview
Problem
Existing pneumatic tire sealants face issues such as excessive flow at elevated temperatures, ineffectiveness across wide temperature ranges, balance and suspension problems due to added weight, and inadequate long-term sealing against punctures, particularly with post-cure sealants.
Innovation Solution
A method involving a sealant composition comprising an elastomer, filler, diluent, quinoid curing agent, and oxidant co-curative, applied to the inner surface of a cured tire, which includes specific components like butyl rubber, polybutene, and crosslinking agents to form a post-tire cure sealant layer that enhances puncture sealing properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid sealant is used in the tire, then puncture sealing capability is improved, but the tire becomes out of balance due to excessive flow at elevated temperatures
Solution Approach 1:
The patent changes the physical and chemical parameters of the sealant by using a viscous non-drying compound instead of a liquid sealant. The sealant has a viscosity of at least 100 Pa·s at 25°C and contains no volatile solvents, preventing flow migration while maintaining sealing capability. This parameter change resolves the contradiction between sealing effectiveness and tire balance.
Solution Approach 2:
The patent uses a composite sealant composition comprising an elastomer (such as butyl rubber or polyisobutylene), a plasticizer, and a curing agent. This composite material provides both the necessary viscosity to prevent flow and the chemical reactivity to form strong adhesive bonds with the tire liner, resolving the contradiction between maintaining position and achieving sealing.
2Stability of the object's composition
If a built-in sealant layer is laminated between tire layers, then structural integrity during vulcanization is improved, but inner liner blister formation occurs due to gas generation at higher temperatures
Solution Approach 1:
The patent applies the sealant composition to the tire liner after vulcanization is complete, rather than incorporating it during the vulcanization process. This preliminary action (post-cure application) avoids exposure to high temperatures and pressures that would cause gas generation and blistering, while still providing sealing capability at lower temperatures.
Solution Approach 2:
The patent uses a thin layer of sealant composition (5-50 micrometers) applied directly to the liner surface, replacing the need for thick built-in sealant layers. This thin disposable layer suffices for sealing without generating harmful effects, resolving the contradiction between structural integrity and blister formation.
3Object-generated harmful factors
If the inner liner thickness is increased to combat blister formation, then blister formation is reduced, but manufacturing cost increases
Solution Approach 1:
The patent extracts the sealant function from the tire structure itself and applies it as a separate coating layer after vulcanization. This separation allows the use of a thin sealant layer (5-50 micrometers) instead of increasing liner thickness, reducing material costs while preventing blister formation through post-cure application at lower temperatures.
4Device complexity
If a post cure sealant layer is applied to the tire, then manufacturing complexity is reduced, but long-term seal against punctures is inadequate
Solution Approach 1:
The patent changes the chemical parameters of the sealant by using a two-part curing system with a quinoid curing agent and an oxidant co-curative. This chemical formulation enables the sealant to cure at lower temperatures after tire assembly, forming strong crosslinked bonds that provide long-term sealing capability while maintaining simple manufacturing processes.
Solution Approach 2:
The patent uses a composite sealant composition containing an elastomer, plasticizer, and specific curing agents that work synergistically. The elastomer provides adhesion and flexibility, the plasticizer maintains low-temperature flexibility, and the curing agents form strong crosslinked networks, collectively providing long-term puncture resistance with simple application.
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 solution provides improved puncture sealing, reduces migration and blister formation, and maintains structural integrity across varying temperatures, while minimizing weight and manufacturing costs, thus addressing the limitations of existing tire sealants.
Implementation Method 1
a sealant composition comprising an elastomer, a filler, a diluent, a quinoid curing agent, an oxidant co-curative
Implementation Method 2
a cure activator of formula 1: wherein R1
Data Source
Figure 1~2
Figure 3
AI summary
A method of making a pneumatic tire and a respective tire (10, 10a) is disclosed. The method comprises the steps of: mixing a sealant composition (20) comprising an elastomer, a filler, a diluent, a quinoid curing agent, an oxidant co-curative; and a cure modifier of the formula wherein R1 and R2 are independently selected to be H or a C1 to C4 alkyl, or R1 and R2 taken together form a substituted or unsubstituted phenylene group, R3 and R4 are independently selected to be H, -OH -NH2, a C1 to C4 alkyl, or -OR5 where R5 is a C1 to C4 alkyl, with the proviso that when R1 and R2 are taken together to form a substituted or unsubstituted phenylene group, R5 is a C1 to C3 alkyl; applying the sealant composition (20) to an inner surface of a cured tire (10, 10a); and curing the sealant composition (20).