Vinyl Chloride-Vinyl Acetate Latex with Controlled Monomer Feeding
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Solution Overview
Problem
Existing methods for preparing vinyl chloride-based copolymers in an aqueous dispersion medium result in latex with low degree of polymerization and low molecular weight due to the differing reactivities of the monomers, leading to poor stability and difficulty in controlling reaction parameters.
Innovation Solution
A semi-continuous emulsion polymerization process is employed, optimizing the feeding mode of vinyl chloride monomer and emulsifier, with controlled additional feeding of initiator, monomer, and emulsifier to manage reaction heat and rate, resulting in high degree of polymerization and uniform particle composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If vinyl chloride monomer and vinyl acetate monomer are polymerized in aqueous dispersion medium, then the process cost is reduced and eco-friendly water-based products are achieved, but the degree of polymerization and molecular weight become low due to different reactivity of monomers
Solution Approach 1:
The patent applies preliminary action by pre-mixing the vinyl chloride monomer and vinyl acetate monomer in specific ratios before polymerization, and by pre-selecting appropriate initiators and emulsifiers. This preliminary preparation ensures that the monomers are properly distributed and ready for controlled polymerization, addressing the reactivity difference issue before the reaction begins, thereby achieving both cost efficiency and controlled molecular weight.
Solution Approach 2:
The patent employs parameter changes by systematically varying polymerization temperature, monomer feed rates, initiator concentration, and emulsifier type to optimize the polymerization process. By adjusting these parameters, the patent achieves high degree of polymerization and molecular weight control while maintaining the benefits of aqueous dispersion medium, thus resolving the contradiction between ease of manufacture and manufacturing precision.
2Ease of manufacture
If vinyl chloride monomer and vinyl acetate monomer are polymerized in aqueous dispersion medium, then the process cost is reduced, but the particle composition uniformity becomes poor
Solution Approach 1:
The patent applies continuity of useful action by using a semi-continuous polymerization process where monomers are fed continuously or in staged batches rather than all at once. This continuous feeding approach maintains steady-state polymerization conditions, ensuring uniform particle composition throughout the reaction while keeping the process simple and cost-effective using aqueous dispersion medium.
Solution Approach 2:
The patent employs dynamics by making the monomer feeding rate adjustable and variable during the polymerization process. The feeding rate is optimized based on reaction progress and heat generation, allowing dynamic adjustment to maintain uniform particle composition. This dynamic control approach resolves the contradiction between process simplicity and composition uniformity.
3Device complexity
If conventional polymerization method is used, then the process is simple, but the reaction heat and reaction rate become difficult to control
Solution Approach 1:
The patent applies segmentation by dividing the polymerization process into distinct stages: initiation stage, propagation stage, and termination stage, with different monomer feeding rates and initiator additions for each stage. This segmentation allows better control of reaction heat and rate while maintaining overall process simplicity. The reaction mixture is also segmented into aqueous dispersion medium and monomer phases, facilitating heat management.
Solution Approach 2:
The patent uses emulsifiers and dispersants as intermediaries to stabilize the polymerization system. These intermediaries create stable micelles and emulsion droplets that control monomer release and polymerization rate, thereby managing reaction heat generation. The intermediaries simplify heat control without requiring complex cooling systems, maintaining process simplicity while improving reliability.
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 produces vinyl chloride-vinyl acetate copolymer latex with high molecular weight and stable particle distribution, suitable for eco-friendly water-based applications without additional processing, enhancing mechanical strength in products like inks, paints, and coatings.
Implementation Method 1
it is intended to solve the above problem by performing an emulsion polymerization of a vinyl chloride monomer and a vinyl acetate monomer in the presence of an aqueous dispersion medium and an emulsifier
Implementation Method 2
a vinyl chloride-based resin is prepared using an oily or aqueous dispersion medium, and may be obtained in the state of latex, in which vinyl chloride-based resin particles are dispersed in the dispersion medium
Implementation Method 3
performing an emulsion polymerization of a vinyl chloride monomer and a vinyl acetate monomer in the presence of an aqueous dispersion medium and an emulsifier
Implementation Method 4
it is possible to obtain a latex including vinyl chloride-vinyl acetate copolymer particles with a high degree of polymerization and a high molecular weight and a uniform particle composition by easily controlling the heat of reaction and reaction rate
Data Source
AI summary
Provided is a method of preparing a vinyl chloride-vinyl acetate copolymer latex.Specifically, in one embodiment of the present invention, provided is a method of preparing a latex including vinyl chloride-vinyl acetate copolymer particles with a high degree of polymerization and molecular weight and a uniform particle composition by performing an emulsion polymerization of a vinyl chloride monomer and a vinyl acetate monomer in the presence of an aqueous dispersion medium and an emulsifier while optimizing a feeding mode of the vinyl chloride monomer and the emulsifier.