Polyurea Adhesion Primer for Metal-Rubber Bonding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional adhesive systems for bonding metal to rubber in tire composites face issues such as weakened adhesion over time due to mechanical and thermal stresses, accelerated degradation by humidity, and increased cost and toxicity from cobalt salts, necessitating the development of more effective and sustainable bonding solutions.
Innovation Solution
A polyurea polymer with sulfur polyaromatic polyamine units is used as an adhesion primer, providing strong bonding between metal reinforcements and unsaturated rubber matrices without the need for cobalt salts, and offering anti-corrosion properties, allowing for the use of simple textile adhesives or direct bonding with functionalized elastomers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional sulfurization brass coating is used to bond steel to rubber, then adhesion is improved, but adhesion weakens over time due to progressive evolution of sulfides under mechanical and thermal stresses
Solution Approach 1:
The invention extracts and eliminates the problematic sulfurization process from the traditional brass coating method. By using a polyurea adhesion primer instead of sulfurized brass, the patent removes the source of sulfide evolution that causes adhesion degradation over time, while maintaining strong initial bonding between metal and rubber.
Solution Approach 2:
The invention changes the chemical composition and bonding mechanism parameters of the adhesion layer. Instead of relying on sulfurized brass with evolving sulfides, the patent introduces a polyurea-based primer with different chemical properties that provides stable, durable adhesion resistant to mechanical and thermal stresses.
2Strength
If cobalt salts are used as adhesion-promoting additives, then adhesion is improved, but rubber compositions become more sensitive to oxidation and aging
Solution Approach 1:
The invention extracts and eliminates cobalt salts from the rubber composition formulation. By using a polyurea adhesion primer applied to the metal surface, the patent removes the need for cobalt salt additives in the rubber compound, thereby eliminating the associated oxidation sensitivity and aging problems while maintaining adhesion promotion.
Solution Approach 2:
The polyurea adhesion primer acts as an intermediary between the metal reinforcement and the rubber composition. This intermediate layer provides adhesion promotion without requiring harmful cobalt salts in the rubber matrix, thus protecting the rubber from oxidation and aging while still achieving strong bonding.
3Strength
If cobalt salts are used as adhesion-promoting additives, then adhesion is improved, but manufacturing cost significantly increases
Solution Approach 1:
The invention extracts and eliminates expensive cobalt salt additives from the rubber composition. By transferring the adhesion promotion function to a polyurea primer applied to the metal surface, the patent removes the need for costly metal salt additives in the rubber compound, significantly reducing material costs.
Solution Approach 2:
The polyurea adhesion primer serves as a cost-effective alternative to expensive cobalt salts. This disposable or consumable primer layer provides the necessary adhesion promotion at a fraction of the cost of metal salt additives, making the overall manufacturing process more economical.
4Ease of manufacture
If traditional adhesive systems are used without polyurea primer, then manufacturing process is simpler, but adhesion durability under stress and humidity is reduced
Solution Approach 1:
The polyurea adhesion primer is applied in advance to the metal reinforcement surface before rubber compounding and vulcanization. This preliminary action prepares the metal surface with a durable adhesion-promoting layer that ensures long-term bonding reliability under stress and humidity, without significantly complicating the overall manufacturing process.
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 polyurea polymer enhances the durability and resistance of metal-rubber composites by maintaining strong adhesion under stress and humidity, eliminating the need for cobalt salts, and providing effective anti-corrosion protection, thus improving the longevity and performance of tire components.
Implementation Method 1
the adhesive interphase between rubber and reinforcements plays a major role in the durability of these performances
Implementation Method 2
the bond between the steel and the rubber matrix being provided by sulfurization brass when vulcanizing or curing rubber
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
The invention relates to polyurea comprising at least urea units, having the formula -NH-CO-NH-, and additional units. Said polyurea is characterized in that said additional units comprise at least one secondary alcohol function and further comprise a secondary ether, thioether, or amino function in the alpha position of the secondary alcohol function. The invention also relates to the use of such a polymer as an adhesion primer for adhering a substrate, for example glass or metal, to an unsaturated rubber, or as an anti-corrosive protective coating for a metal substrate. The invention also relates to a metal reinforcement such as a wire, cable, film, or plate that is coated with a polymer according to the invention.