Cross-linked Polymer Capsules for Additive Dispersion in Tyre Compounds
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Solution Overview
Problem
The incorporation of additives into elastomeric compounds for tires is hindered by poor dispersibility, leading to non-homogeneous distributions and sub-optimal properties due to the chemical affinity issues between additives and the elastomeric mass, particularly affecting vulcanizing agents and accelerants.
Innovation Solution
The use of cross-linked polymer capsules coated with materials like cellulose derivatives, starch, and phenol-formaldehyde resins to encapsulate additives, which provides high affinity and thermal stability, allowing for better dispersion and controlled release of additives during the vulcanization process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If additives are incorporated directly into elastomeric material, then the process is simple, but dispersibility is poor leading to non-homogeneous distribution
Solution Approach 1:
The patent uses an organic solvent as an intermediary medium to dissolve both the elastomeric polymer and additives before mixing. This solvent-mediated approach allows all components to be thoroughly combined in a homogeneous solution, eliminating the dispersibility problems associated with direct mixing of solid additives into elastomeric material. The solvent acts as a bridge that enables complete compatibility between incompatible components.
Solution Approach 2:
The patent changes the physical state and solubility parameters of the components by using a common organic solvent system. By selecting a solvent that dissolves both the elastomeric polymer and the additives, the patent transforms the mixing process from a solid-state dispersion problem into a liquid-phase solution process, thereby achieving homogeneous distribution.
2Quantity of substance
If additives are used in small quantities (a few phr), then the compound composition is optimized, but dispersion becomes even more critical and difficult
Solution Approach 1:
The organic solvent serves as a mediator that ensures even trace amounts of additives are uniformly distributed throughout the elastomeric compound. The solvent allows complete dissolution and mixing at the molecular level, preventing aggregation or clumping of small quantities of additives that would otherwise be difficult to disperse uniformly.
Solution Approach 2:
The patent performs preliminary dissolution of additives in the organic solvent before incorporating them into the elastomeric polymer. This preliminary action ensures that even small quantities of additives are pre-dissolved and ready for uniform distribution, eliminating the need for intensive mixing that would be required to achieve homogeneous dispersion of undissolved particles.
3Device complexity
If non-cross-linked capsules are used to encapsulate additives, then release occurs at low temperatures, but thermal stability during processing is reduced
Solution Approach 1:
The patent creates a composite capsule structure where the capsule wall is formed by polymerization of vinyl monomers in the presence of the elastomeric polymer. This composite structure combines the properties of the capsule wall material (which provides controlled release) with the elastomeric polymer (which provides thermal stability and compatibility with the final product). The composite nature allows the capsule to withstand processing temperatures while still enabling controlled release of additives.
Solution Approach 2:
The patent applies different properties to different parts of the capsule system: the capsule wall has specific permeability and degradation characteristics for controlled additive release, while the elastomeric polymer matrix provides thermal stability and mechanical strength. This local differentiation of properties allows the system to achieve both controlled release and thermal stability simultaneously.
4Strength
If cross-linked polymer capsules are used, then thermal and mechanical stability is enhanced, but the capsule preparation process becomes more complex
Solution Approach 1:
The patent merges the capsule formation process with the elastomeric compound preparation process. The vinyl monomers are polymerized in situ within the elastomeric compound matrix, combining two processes (capsule synthesis and compound formulation) into one. This eliminates the need for separate capsule manufacturing and loading steps, reducing overall process complexity while maintaining the benefits of cross-linked capsule structure.
Solution Approach 2:
The elastomeric compound matrix itself serves as the medium for capsule formation and stabilization. The cross-linked polymer capsules form and maintain their structure within the elastomeric matrix, which provides the necessary mechanical support and thermal stability. The system is self-supporting, eliminating the need for additional external structures or processes.
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
This approach ensures homogeneous distribution of additives, enhances the thermal and mechanical stability of the elastomeric compounds, and protects additives from environmental degradation, resulting in improved tire performance and processing efficiency.
Implementation Method 1
cross-linked polymer obtained by cross-linking at least one cross-linkable polymer
Implementation Method 2
coating comprises at least one cross-linked polymer obtained by cross-linking at least one cross-linkable polymer selected from cellulose derivatives, starch and derivatives, chitosans, alginates, polyesters, phenol-formaldehyde resins, urea-formaldehyde resins
Implementation Method 3
capsule comprising a coating and a core, wherein the coating comprises at least one cross-linked polymer... and the core comprises at least one additive for tyre compounds
Data Source
Figure 1
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AI summary
The present invention relates to capsules comprising additives for tyre compounds, to processes for the preparation thereof, to the use thereof for an optimal dispersion of the same in elastomeric tyre compounds and to the compounds thus obtained. The capsules of the invention are characterised by a cross-linked coating, which imparts considerable thermal and mechanical resistance to them, thus allowing said additives and fillers to be distributed efficiently and uniformly.