Carbon Black Masterbatching for Silica-Filled Diene Rubber
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Solution Overview
Problem
Existing rubber compositions face challenges in achieving optimal dispersion and processing of inorganic fillers like silica, which tend to clump together in the elastomeric matrix, limiting reinforcing properties and increasing viscosity, making them difficult to process.
Innovation Solution
A process involving liquid-phase compounding of diene elastomer latex with an aqueous dispersion of carbon black in a coagulation reactor, followed by incorporation of inorganic fillers like silica, results in a masterbatch with improved dispersion and hysteresis, maintaining good filler distribution and processability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If inorganic filler like silica is incorporated into the elastomeric matrix, then reinforcing properties are improved, but filler tends to clump together forming aggregates that limit dispersion
Solution Approach 1:
The patent employs silane coupling agents as intermediary substances that chemically bond to both the inorganic filler particles and the elastomer matrix. This mediator prevents direct aggregation of silica particles by creating a protective interface layer, enabling both high filler content for reinforcement and uniform dispersion without clumping.
Solution Approach 2:
The patent modifies the surface parameters of inorganic filler particles through silane treatment, changing their chemical and physical properties. This parameter change reduces surface energy and improves compatibility with the elastomer matrix, preventing aggregation and enabling uniform distribution while maintaining high reinforcing efficiency.
2Strength
If inorganic filler content is increased to improve reinforcing properties, then viscosity in uncured state increases making processing more difficult
Solution Approach 1:
Silane coupling agents serve as intermediaries that reduce interparticle friction and improve filler-matrix compatibility. This mediation allows higher filler loads to be incorporated while maintaining acceptable viscosity levels and processability during mixing and molding operations.
Solution Approach 2:
The patent changes the surface chemical parameters of inorganic filler through silane modification, which reduces particle-particle interactions and prevents network formation. This parameter change enables higher filler content to be achieved without excessive viscosity increase, improving both reinforcement and processability.
3Ease of manufacture
If conventional solid-phase compounding is used, then processing is simpler, but filler dispersion is insufficient leading to poor reinforcing properties
Solution Approach 1:
The patent applies silane coupling agent treatment to inorganic filler particles before compounding with the elastomer. This preliminary action pre-modifies the filler surface to improve compatibility and dispersion, enabling effective reinforcement while maintaining relatively simple processing procedures.
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 process achieves a Z value of greater than or equal to 60 for filler dispersion, enhancing reinforcing properties while maintaining processability, suitable for tire components.
Implementation Method 1
the compounding of these two fluids being sufficiently energetic to make it possible to almost completely coagulate the elastomer latex with the filler before the outlet orifice of the coagulation reactor
Implementation Method 2
and then in drying the coagulum obtained
Data Source
AI summary
A process for preparing a rubber composition based on at least one diene elastomer, a filler comprising at least carbon black and an inorganic filler with an inorganic filler content of less than or equal to 50 parts by weight per hundred parts of elastomer, and a crosslinking system is disclosed. The process comprises preparing a first masterbatch of diene elastomer and of carbon black; drying a coagulum obtained; and incorporating the inorganic filler and the other constituents of the composition.