Peroxide Emulsion Stability via Low Viscosity Polyvinyl Acetate
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Solution Overview
Problem
Existing organic peroxide emulsions for polymerization of ethylenically unsaturated monomers, such as vinyl chloride, face challenges in maintaining stable droplet size and low viscosity, which are crucial for preventing decomposition and ensuring transparency and flowability, especially at low temperatures.
Innovation Solution
An aqueous composition using polyvinyl acetate as an emulsifier with a high degree of hydrolysis greater than 80% and low intrinsic viscosity, combined with an antifreeze agent and a nonionic surfactant, stabilizes peroxide droplets to maintain a small average size and low viscosity, ensuring stability and flowability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If polyvinyl acetate with high degree of hydrolysis (>68%) is used as emulsifier, then droplet size stability is improved, but emulsion viscosity increases excessively
Solution Approach 1:
The patent applies parameter changes by precisely controlling two critical parameters of the polyvinyl acetate emulsifier: the degree of hydrolysis is limited to 68% or less, and the intrinsic viscosity is limited to 1.5 dl/g or less. This dual parameter control resolves the contradiction by selecting specific ranges that provide sufficient droplet stabilization without causing excessive emulsion viscosity, thereby enabling both stability and processability.
2Stability of the object's composition
If droplet size is reduced to maintain stability, then emulsion viscosity increases, but flowability deteriorates
Solution Approach 1:
The patent resolves this contradiction through parameter changes by controlling the intrinsic viscosity of the polyvinyl acetate emulsifier to be 1.5 dl/g or less. This parameter control allows the formulation to achieve both small droplet sizes (d50 ≤ 10 μm) for stability and low enough viscosity (≤ 1000 mPa·s at -10°C) to maintain flowability during handling and polymerization processes.
3Manufacturing precision
If polyvinyl acetate with high degree of hydrolysis is used, then droplet size control is improved, but emulsion becomes too viscous for handling
Solution Approach 1:
The patent applies parameter changes by establishing specific limits for polyvinyl acetate properties: degree of hydrolysis ≤ 68% and intrinsic viscosity ≤ 1.5 dl/g. These parameter specifications enable precise droplet size control (d50 ≤ 10 μm, d100 ≤ 20 μm) while maintaining emulsion viscosity at manageable levels (≤ 1000 mPa·s at -10°C), thus resolving the contradiction between manufacturing precision and ease of manufacture.
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 achieves stable droplet sizes below 10 μm and low viscosity, allowing for efficient polymerization and copolymerization processes while maintaining emulsion stability and fluidity over extended storage periods.
Implementation Method 1
An organic peroxide emulsion consists of droplets of peroxide stabilized by an emulsifier
Implementation Method 2
these emulsions include an antifreeze, allowing the emulsion to be maintained in liquid form at temperatures below -10°C
Implementation Method 3
The presence of water, as a heat transfer fluid, makes it possible to absorb and dissipate the energy generated in the event of possible decomposition of the peroxides
Implementation Method 4
the use of polyvinyl acetate having a high degree of hydrolysis with a very low intrinsic viscosity
Data Source
AI summary
The invention concerns an aqueous emulsion composition of organic peroxide, comprising: - from 10 to 65% by weight of one or a plurality of organic peroxides, - from 2 to 25% by weight of at least one antifreeze agent, - from 0.01 to 10% by weight of at least one emulsifying agent, - optionally at least one additive, - water, of which the quantity is defined in order to form the remainder of the total composition (100%), characterised in that the emulsifying agent is a colloid agent consisting of a polyvinyl acetate having a degree of hydrolysis greater than 80% and a viscosity, measured in solution in water at 4 % by weight at 20°C, less than or equal to 5 mPa.s, said viscosity being measured with a Brookfield RVT viscometer, needle no. 3, 20 rpm, in accordance with the ISO 2555 standard. The invention also relates to the method of preparing same and the use thereof.