Artificial Latex Emulsification via Controlled Rotor Tip Speed
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Solution Overview
Problem
Existing processes for producing artificial latexes face challenges with emulsion stability, mechanical instability, and molecular weight reduction during the emulsification step, particularly in scaling up to commercial sizes, which affects the particle size and distribution of the latex.
Innovation Solution
A process involving the formation of a premix using a hydrocarbon solvent and an aqueous soap solution, followed by homogenization with a rotor/stator homogenizer at specific tip speeds to create a stable oil-in-water emulsion with median particle sizes between 0.5 to 2.0 μm, using a combination of homogenizers and a static mixer in a recycle loop to maintain molecular weight and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional emulsification processes are used to produce artificial latex, then the latex can be produced, but the emulsion becomes unstable and the molecular weight of the rubber is reduced
Solution Approach 1:
The patent applies parameter changes by precisely controlling the rotor tip speed (15-30 m/s) and stator- rotor gap (0.5-2 mm) in the homogenizer, and by controlling the temperature (20-40°C) during emulsification. These parameter optimizations enable effective emulsification while minimizing molecular weight reduction and maintaining emulsion stability.
Solution Approach 2:
The patent uses a surfactant as an intermediary substance to stabilize the emulsion during the emulsification process. The surfactant acts as a mediator between the hydrocarbon solvent and water, preventing coagulation and molecular weight reduction while maintaining emulsion stability throughout the process.
2Stability of the object's composition
If high shear mixing is used to create stable emulsion, then emulsion stability improves, but molecular weight of the rubber decreases due to mechanical degradation
Solution Approach 1:
The patent optimizes the shear mixing parameters by controlling the rotor tip speed within 15-30 m/s and the stator-rotor gap within 0.5-2 mm. This controlled approach provides sufficient shear force for stable emulsion formation while minimizing mechanical degradation and molecular weight reduction of the rubber.
Solution Approach 2:
The patent employs continuous emulsification using a rotor-stator homogenizer operating at controlled speeds. The continuous action at optimized parameters ensures stable emulsion formation without excessive mechanical stress that would cause molecular weight reduction, maintaining both stability and polymer integrity.
3Productivity
If the emulsification process is scaled up to commercial sizes, then production capacity increases, but variability in particle size and distribution increases
Solution Approach 1:
The patent employs continuous emulsification using a rotor-stator homogenizer, which maintains consistent shear conditions throughout the process. This continuous action ensures uniform particle size distribution even at commercial production scales, eliminating the variability that occurs with batch processing scaling.
Solution Approach 2:
The patent maintains precise control over critical parameters (rotor tip speed 15-30 m/s, stator-rotor gap 0.5-2 mm, temperature 20-40°C) during scaled-up production. This parameter control ensures that particle size and distribution remain consistent regardless of production volume, enabling reliable commercial-scale manufacturing.
4Ease of manufacture
If mechanical agitation is used during emulsification, then mixing efficiency improves, but coagulation occurs and equipment becomes coated with coagulated rubber
Solution Approach 1:
The patent introduces a surfactant as an intermediary that prevents direct coagulation of rubber particles during mechanical agitation. The surfactant forms a protective interface between the polymer and aqueous phases, allowing efficient mixing without the coagulation and equipment coating problems that occur with conventional agitation methods.
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 process achieves stable emulsions with maintained molecular weight and desired particle size distribution, reducing variability and improving the scalability of the latex production, ensuring the quality of the final product for applications like gloves and condoms.
Implementation Method 1
homogenization with a rotor/stator homogenizer at specific tip speeds to create a stable oil-in-water emulsion
Implementation Method 2
operated at a tip speed of the outer ring of the rotor in the range of from 8 to 16 m/s, and wherein the premix is subsequently homogenized in a rotor/stator homogenizer operated at a tip speed of the outer ring of the rotor in the range of from 16 to 35 m/s
Data Source
AI summary
A process of producing an artificial latex, comprising the steps:(a) cement formation, wherein a rubber is dissolved in a suitable hydrocarbon solvent;(b) emulsification of the cement formed in step (a), together with an aqueous soap solution, thus forming an oil-in-water emulsion;(c) hydrocarbon solvent removal, resulting in a latex of the rubber having particles of a median particle size in the range of from about 0.5 to 2.0 μm, and optionally(d) latex concentration, forming an artificial latex with a higher solids content, characterized in that in step (b) a premix is formed first, which is subsequently homogenized into an oil-in-water emulsion, and wherein the premix is formed by mixing the cement with the aqueous soap solution at a volume ratio of 1:1.5 to 1:3 using at least one homogenizer comprising a stator and a rotor, that is operated at a tip speed of the outer ring of the rotor in the range of from 8 to 16 m/s, and wherein the premix is subsequently homogenized in a rotor/stator homogenizer operated at a tip speed of the outer ring of the rotor in the range of from 16 to 35 m/s.