Elastomeric Copolymer Particles Anti-Agglomeration LCST Process
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Solution Overview
Problem
Elastomeric ethylene/α-olefin copolymer particles tend to agglomerate during processing, leading to fouling and process disruptions, and existing anti-agglomerants like calcium stearate and talcum interfere with cure systems and cause haziness, necessitating a more effective anti-agglomerant solution.
Innovation Solution
A process involving an organic medium with elastomeric ethylene/α-olefin copolymer and an organic diluent is contacted with an aqueous medium containing a Lower Critical Solution Temperature (LCST) compound, which precipitates above a certain temperature, reducing agglomeration and allowing for the formation of a stable aqueous slurry with minimal residual diluent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fatty acid salts of multivalent metal ions (calcium stearate, zinc stearate) are added as anti-agglomerants, then the elastomeric ethylene/α-olefin copolymer particles show reduced tendency to agglomerate and stay suspended, but the chemical interaction with cure systems causes slower cure times and haziness in the final product
Solution Approach 1:
The patent removes harmful multivalent metal ion salts and talcum from the process by extracting the anti-agglomerant function and assigning it to the LCST compound instead, which prevents agglomeration without interfering with cure systems or causing haziness
Solution Approach 2:
The LCST compound acts as an intermediary substance that mediates between the elastomeric particles and the aqueous medium, providing anti-agglomerant properties through its temperature-dependent solubility behavior rather than through chemical interaction with the polymer or cure system
2Reliability
If traditional wet finishing process with multivalent metal ion salts is used, then anti-agglomerant effect is achieved, but chemical interaction with cure systems occurs causing slower cure times
Solution Approach 1:
The LCST compound functions as a temporary, process-specific anti-agglomerant that is effective only during the aqueous slurry formation and handling stages, and can be easily removed or becomes inert after drying, unlike persistent metal salt additives that continue to interfere with curing
Solution Approach 2:
The patent changes the fundamental parameter of anti-agglomerant mechanism from chemical interaction (metal salts) to physical phase behavior (LCST temperature-dependent solubility), allowing control of particle suspension through temperature rather than chemical composition
3Reliability
If talcum is added as anti-agglomerant, then particle agglomeration is reduced, but haziness is caused in the final product
Solution Approach 1:
The patent extracts the anti-agglomerant function from solid particulate additives like talcum and transfers it to a soluble LCST compound that provides suspension stability through molecular-level interactions rather than particle-particle contact, eliminating the scattering effect that causes haziness
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 effectively prevents agglomeration of elastomeric ethylene/α-olefin copolymer particles in aqueous media, reducing the need for multivalent metal ion salts and talcum, thereby improving process efficiency and product purity by maintaining the particles in a suspended state without interfering with cure systems.
Implementation Method 1
an aqueous medium comprising at least one LCST compound having a cloud point of 0 to 100°C, preferably 5 to 100°C, more preferably 15 to 80°C and even more preferably 20 to 70°C
Implementation Method 2
contacting an organic medium comprising i) at least one elastomeric ethylene/α-olefin copolymer and ii) an organic diluent with an aqueous medium
Data Source
AI summary
The teachings herein relates to elastomeric particles including 98.5 weight percent or more of an elastomeric ethylene/α-olefin copolymer. The copolymer preferably has a weight average molecular weight of 10 to 2,000 kg/mol. The copolymer preferably has a Mooney viscosity of at least 10 (ML 1+4 at 125° C., ASTM D1646). The particles preferably include 0 to 0.4 weight percent of salts of multivalent metal ions. The salts of multivalent metal ions preferably includes stearates and palmitates of multivalent metal ions. The elastomeric ethylene/α-olefin copolymer preferably is an EPM or an EPDM. The blends including the particles preferably comprise a different elastomer, a filler, or a curing system.