Kneader Shearing for Elastomer Solvent Removal
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Solution Overview
Problem
Current processes for finishing elastomers, such as isobutylene-based elastomers, are inefficient and unsuitable for temperature-sensitive types like halogenated isobutylene-based elastomers, as they struggle with dewatering and drying due to varying slurry chemistries and viscoelasticity, necessitating a more effective method for devolatizing and drying large capacities of these materials.
Innovation Solution
A process involving a kneader with specific paddle and hook configurations is used to shear isobutylene-based elastomer streams, effectively volatilizing hydrocarbon liquids and increasing the elastomer solids content, while controlling temperature to maintain processability and prevent scorching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional dewatering and drying processes are used for isobutylene-based elastomers, then the process can handle EPDM elastomers effectively, but it fails to efficiently remove solvents from isobutylene-based elastomers due to differences in slurry chemistry and viscoelasticity
Solution Approach 1:
The patent changes the fundamental parameters of the finishing process by using a kneader with specific paddle and hook configurations that create intense shear forces, rather than relying on conventional extruder-based dewatering. This allows the process to adapt to the unique rheological properties of isobutylene-based elastomers while maintaining high solvent removal efficiency
Solution Approach 2:
The kneader is divided into multiple zones with different paddle and hook configurations along its length, allowing each section to handle specific aspects of solvent removal and elastomer processing. This segmentation enables the system to handle varying slurry chemistries and viscoelasticity profiles effectively
2Productivity
If high shear forces are applied to remove solvents from elastomer slurry, then solvent removal efficiency increases, but temperature-sensitive halogenated isobutylene-based elastomers may scorch or degrade
Solution Approach 1:
The kneader operates continuously with sustained shear forces that efficiently remove solvents without requiring high-temperature intervals. The continuous action maintains controlled temperature throughout the process while achieving thorough solvent removal, preventing thermal degradation of temperature-sensitive elastomers
Solution Approach 2:
The kneader acts as an intermediary device that transfers mechanical shear energy to the elastomer slurry in a controlled manner, mediating between the need for efficient solvent removal and the requirement to protect temperature-sensitive elastomers from thermal degradation
3Productivity
If a single finishing line is used to process large capacities of isobutylene-based elastomers, then production capacity increases, but the process becomes more complex and difficult to control
Solution Approach 1:
The kneader is designed as a universal finishing device that can handle various types of isobutylene-based elastomers and different slurry chemistries through a single integrated system. The standardized design with adjustable parameters simplifies operation and control while maintaining high processing capacity
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 significantly increases the elastomer solids content in the stream, efficiently removing solvents and diluents, and maintains the elastomer's properties by limiting temperature exposure, enabling the processing of large capacities of isobutylene-based elastomers, including temperature-sensitive variants.
Implementation Method 1
shearing the elastomer in the stream between the paddles and hooks whereby the elastomer is subjected to shearing forces and at least a portion of the hydrocarbon liquids is volatized from the stream
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
In the production of isobutylene-based elastomers the product obtained from the polymerization process is often in the form of a stream. Described herein are an apparatus and a process for removal of hydrocarbon liquids from the elastomer. The process comprises the steps of obtaining a stream comprising hydrocarbon liquids, either solvents or diluents, and an isobutylene-based elastomer; passing the stream through a kneader to volatize the hydrocarbon liquids from the elastomer.