Batchwise High-Shear Mixer for Silicone Composition
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Solution Overview
Problem
Current methods for producing silicone compositions face challenges in achieving high productivity while maintaining quality consistency, particularly with high bulk density fillers, leading to prolonged processing times and increased energy consumption.
Innovation Solution
A method involving a batchwise high-shear mixer with a rotatable mixing pan, eccentric high-speed agitator, and stationary scraper for kneading organopolysiloxane and fillers with a BET surface area of at least 10 m²/g, allowing for efficient mixing and heat treatment under controlled conditions to produce a silicone composition of consistent quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If batchwise large-size mixers are used to produce compounds of consistent quality, then manufacturing precision is improved, but productivity deteriorates due to very long powder mixing times
Solution Approach 1:
The patent changes the mixing parameters by using high shear stress (intense mechanical action) combined with high temperature (100-200°C) and reduced pressure conditions. This parameter transformation allows rapid mixing of fillers with high bulk density while maintaining compound quality consistency, resolving the contradiction between manufacturing precision and productivity
Solution Approach 2:
The patent employs periodic heating and heat treatment cycles during the mixing process. The intermittent application of thermal energy accelerates the mixing kinetics and promotes uniform filler distribution, enabling both high productivity and consistent quality output
2Productivity
If mixing vessel volume is increased to increase productivity, then productivity is improved, but use of energy deteriorates due to accordingly higher power requirements
Solution Approach 1:
The patent transforms the mixing approach by applying high temperature and reduced pressure parameters, which dramatically accelerates the mixing process. This allows achieving high productivity in a compact mixer volume, thereby avoiding the energy penalty associated with large-scale mixers while maintaining high output rates
3Productivity
If twin-screw continuous kneader/extruder units are used to achieve high productivity, then productivity is improved, but manufacturing precision deteriorates due to problems in metering, feeding, and pumping of filler
Solution Approach 1:
The patent extracts the filler addition step from the continuous processing line and performs it separately in the batchwise mixer before combining with the organopolysiloxane. This separation eliminates the metering and feeding problems inherent in continuous systems, ensuring both high productivity and consistent quality
Solution Approach 2:
The patent performs preliminary mixing of the filler with a portion of the organopolysiloxane to form a pre-mixed composition, which is then combined with the remaining organopolysiloxane. This preliminary action ensures uniform filler distribution and eliminates quality consistency issues while maintaining high productivity
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 enables the preparation of silicone compositions with improved fluidity and physical properties within a short time, reducing energy consumption and accommodating various types of compositions, thus enhancing productivity and energy efficiency.
Implementation Method 1
batchwise high-shear mixer with a rotatable mixing pan, eccentric high-speed agitator
Implementation Method 2
kneading organopolysiloxane and fillers with a BET surface area of at least 10 m²/g, allowing for efficient mixing and heat treatment
Data Source
Figure 1
AI summary
A silicone composition comprising an organopolysiloxane containing at least two silicon-bonded alkenyl and/or hydroxyl groups in the molecule and a filler having a BET surface area of at least 10 m2/g is prepared by kneading the components in a batchwise high-shear mixer. The mixer includes a rotatable mixing pan (1), a high-speed rotation agitator (3) disposed eccentrically in the pan, and a stationary scraper (4) disposed in the pan for creating a vertical counterflow.