Aqueous EVA Pour Point Dispersion Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing pour point depressant compositions for crude oils face challenges in maintaining a low pour point over a broad temperature range and long-term stability against creaming, particularly when using ethylene vinyl acetate copolymers dispersed in an aqueous medium, as they often require flammable solvents and struggle with high melting points and inadequate dispersion.
Innovation Solution
A method involving the combination of ethylene vinyl acetate copolymer, a dispersing agent such as sodium or potassium salts of oleic acid, and a stabilizing agent like polyvinyl alcohol, in an extruder to form an aqueous dispersion with a specific particle size and ratio of water to freezing point depressant, ensuring the composition remains liquid and stable from ambient to 40°C.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If EVA copolymer is dispersed in aqueous medium without flammable solvents, then safety and environmental performance improve, but dispersion quality and stability deteriorate due to high melting point and inadequate dispersibility
Solution Approach 1:
The patent introduces a dispersing agent as an intermediary substance between the EVA copolymer and aqueous medium. This dispersing agent facilitates the dispersion of hydrophobic EVA particles in water without requiring flammable organic solvents, thereby maintaining safety while improving dispersion quality and stability.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the dispersion system by controlling particle size (reducing to sub-micron range), adjusting concentration ratios, and optimizing the composition of the dispersing agent. These parameter changes enable stable dispersion of EVA in aqueous medium without flammable solvents.
2Reliability
If EVA copolymer with low vinyl acetate content is used, then pour point depression effectiveness improves, but melting point increases making dispersion difficult
Solution Approach 1:
The patent applies preliminary action by pre-heating the EVA copolymer above its melting point before adding the dispersing agent and aqueous medium. This preliminary heating softens the polymer, making it more amenable to dispersion. Additionally, the dispersing agent is pre-prepared and added at the optimal moment to maximize its effectiveness during the dispersion process.
Solution Approach 2:
The dispersing agent serves as a mediator that bridges the incompatibility between the hydrophobic EVA copolymer and hydrophilic aqueous medium. It reduces the interfacial tension and prevents aggregation, enabling effective dispersion of low vinyl acetate content EVA that would otherwise be difficult to disperse due to its high melting point.
3Quantity of substance
If high solids content is achieved in aqueous EVA dispersion, then economic efficiency improves, but flowability at low temperatures deteriorates
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: controlling particle size distribution (sub-micron range), adjusting the molecular weight and vinyl acetate content of the EVA copolymer, optimizing the concentration and type of dispersing agent, and controlling the water-to-EVA ratio. These coordinated parameter changes enable the dispersion to maintain both high solids content and good low-temperature flowability.
Solution Approach 2:
The patent creates a composite dispersion system comprising EVA copolymer particles, dispersing agent molecules, and water. This composite structure allows the system to exhibit properties that neither component alone could provide: high solids content from the concentrated EVA particles, while maintaining flowability through the dispersing agent that prevents aggregation and ensures uniform distribution.
4Device complexity
If conventional dispersion techniques are used without dispersing agents, then process complexity is reduced, but dispersion quality and long-term stability are insufficient
Solution Approach 1:
The dispersing agent acts as an intermediary that simplifies the overall process by enabling effective dispersion in a single step without requiring complex multi-stage processing equipment or procedures. The dispersing agent molecules adsorb onto the EVA particle surfaces, providing steric or electrostatic stabilization that prevents creaming and aggregation, thereby achieving long-term stability with a relatively simple dispersion process.
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 method effectively lowers the pour point of crude oils, maintains stability against creaming, and avoids the use of flammable solvents, ensuring the composition remains effective and safe across a broad temperature range.
Implementation Method 1
a dispersing agent, preferably a sodium salt of oleic acid, stearic acid, behenic acid or erucic acid
Implementation Method 2
mixing the aqueous dispersion of EVA with iv) an aqueous freezing point depressant, preferably sodium chloride, potassium chloride, calcium chloride, methanol, ethanol, propanol, propylene glycol, glycerine
Data Source
Figure 1
AI summary
The present invention relates to an aqueous pour point depressant dispersion composition comprising a thermoplastic polymer, preferably ethylene vinyl acetate (EVA); a dispersing agent; water; optionally an aqueous freezing point depressant; and optionally a stabilizing agent wherein the volumn average particle size of the dispersed thermoplastic polymer is equal to or less than 1 micrometers and a method to make and use said composition.