Elastomer Compound Dry Mixing at Low Temperatures
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Solution Overview
Problem
High temperatures during the dry mixing of elastomer composite masterbatches can degrade the rubber compounds, leading to undesirable reductions in molecular weight and mechanical properties, especially when using natural rubber and higher surface area carbon blacks.
Innovation Solution
Dry mixing of elastomer composite masterbatches is conducted at temperatures below 130°C, with specific temperature ranges for one-stage or two-stage processes, to prevent degradation and enhance properties such as hysteresis and reinforcement, while reducing energy consumption and processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If longer and more intensive mixing is used to achieve better carbon black macro-dispersion, then dispersion quality is improved, but the molecular weight of the elastomer is reduced due to mechanical/thermal degradation
Solution Approach 1:
The mixing process is divided into multiple stages with different intensity levels. A first stage of intensive mixing achieves initial dispersion, followed by a second stage of gentler mixing that completes dispersion without excessive degradation. This segmentation allows the process to achieve good macro-dispersion while limiting molecular weight loss by reducing continuous high-intensity mechanical stress on the elastomer chains.
2Manufacturing precision
If higher mixing intensity is applied to improve carbon black dispersion, then dispersion uniformity is enhanced, but mechanical properties of the rubber compound are degraded
Solution Approach 1:
The mixing process employs periodic variation in mixing intensity rather than continuous high-intensity mixing. The mixer operates at high intensity for predetermined intervals to achieve dispersion, then reduces intensity or pauses briefly. This periodic action pattern allows carbon black particles to progressively separate and distribute uniformly throughout the elastomer while giving the polymer chains periodic relief from mechanical stress, thereby preserving mechanical properties.
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 method maintains or improves mechanical reinforcement and hysteresis properties of elastomer compounds, achieving equivalent or superior results compared to traditional high-temperature dry mixing processes, with reduced energy usage and processing time.
Implementation Method 1
elastomer latex or synthetic rubber solution is combined in a liquid form with particulate filler slurry fluid to produce elastomer composite
Implementation Method 2
The latex and carbon black slurry are mixed and coagulated in the coagulation tank into small beads
Implementation Method 3
Dry mixing of elastomer composite masterbatches is conducted at temperatures below 130°C, with specific temperature ranges for one-stage or two-stage processes, to prevent degradation and enhance properties
Data Source
AI summary
Methods to prepare elastomer compounds are described that include dry mixing at least one additive to an elastomer composite masterbatch at low temperatures over a shortened mixing cycle with reduced energy consumption. The elastomer composite masterbatch is produced in a liquid masterbatch process. The resulting elastomer compounds are further described as well as property improvements that can be achieved.