Multimodal Elastomer Composition for Viscosity Management
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Solution Overview
Problem
Elastomeric polymer compositions with high Mooney viscosity are difficult to process due to their long polymer chains, leading to increased manufacturing costs and performance sacrifices, as they often require extender oils to reduce viscosity, which add weight and cost.
Innovation Solution
A multimodal elastomer composition with a blend of 85-95% of a first polymer fraction and 5-15% of a second polymer fraction, where the second fraction has significantly higher Mooney viscosity, achieved through a series reactor blend process using Ziegler-Natta polymerization, allowing for higher Mooney viscosities without extender oil, enhancing processing ease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If higher Mooney viscosity polymers are used to gain strength and desired properties, then the strength and performance of finished articles are improved, but the difficulty of processing the polymer composition increases
Solution Approach 1:
The patent applies segmentation by creating a multimodal polymer composition divided into distinct molecular weight fractions (first fraction with lower Mooney viscosity and second fraction with higher Mooney viscosity). This allows the composition to exhibit both easy processability (from the lower viscosity fraction) and high strength (from the higher viscosity fraction), resolving the contradiction between strength and ease of manufacture.
Solution Approach 2:
The patent changes the parameter of molecular weight distribution by controlling the polymerization process to produce a multimodal distribution with specific Mooney viscosity ranges for each fraction. By adjusting the proportion and viscosity characteristics of each fraction, the composition achieves optimal balance between processability and strength.
2Ease of manufacture
If extender oil is added to lower the effective viscosity of the polymer composition, then the processability is improved, but the performance of the polymer deteriorates and the weight increases
Solution Approach 1:
The patent extracts the need for extender oil by incorporating lower viscosity polymer fraction directly into the composition. This eliminates the harmful effect of adding external oils while maintaining processability, as the low viscosity fraction naturally provides fluidity without the weight and performance penalties of extender oil additives.
Solution Approach 2:
The patent creates a composite polymer composition by blending polymer fractions with different molecular weights and viscosity characteristics. This composite structure provides the flow properties of lower viscosity materials and the strength of higher viscosity materials, replacing the need for extender oil additives.
3Ease of manufacture
If extender oil is added to reduce viscosity, then the effective viscosity of the polymer composition is lowered, but the cost for the elastomer producer and downstream manufacturer increases
Solution Approach 1:
The patent uses inexpensive polymer fractions with different viscosity characteristics that are produced as byproducts or intermediate products during polymerization. These fractions are blended to achieve desired processability without requiring expensive extender oil additives, thereby reducing overall material costs.
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 composition exhibits superior processing performance with lower viscosity in downstream formulations, maintaining strength and elasticity benefits of high Mooney viscosities without the need for extender oils, thus reducing costs and improving manufacturing efficiency.
Implementation Method 1
The polymerization process employs a Ziegler-Natta catalyst system comprising a catalyst and co-catalyst
Data Source
AI summary
Provided herein are multimodal elastomer compositions comprising a first polymer fraction and a second polymer fraction, and methods for making such compositions. The elastomer compositions are preferably ethylene, a-olefin, copolymers or ethylene, a-olefin, polyene terpolymers. The elastomer compositions have high Mooney viscosity, thereby providing for improved elastomeric properties in compounds and other articles formed from the elastomer compositions. Surprisingly, the high Mooney viscosity compositions exhibit a much lower than expected viscosity when formulated into elastomer compounds. Thus, the processing detriments typically associated with high Mooney viscosity elastomers are minimized through the use of the elastomer compositions, and methods for making them, disclosed herein.