Semicontinuous Copolymer Metering for Concrete Superplasticizers
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Solution Overview
Problem
Existing processes for preparing copolymers as superplasticizers for hydraulic binders require excessive mixing water, leading to poorer mechanical strengths and stabilities in concrete due to excess water, and there is a need for a more cost-efficient and high-quality production method.
Innovation Solution
A semicontinuous process in a polymerization apparatus where acid monomer and polyether macromonomer are reacted with a free radical polymerization initiator in a controlled molar ratio, with acid monomer metered over a limited time period to form a copolymer with improved uniform distribution of comonomer units, enhancing metering efficiency and performance characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If acid monomer is metered slowly over a long period to ensure uniform copolymer composition, then composition uniformity is improved, but production capacity and cost-efficiency deteriorate
Solution Approach 1:
The patent applies dynamic metering where the acid monomer addition rate is continuously adjusted based on real-time monitoring of copolymer composition and reaction conditions. This dynamic control allows the system to maintain composition uniformity while optimizing the overall metering rate for higher productivity, resolving the contradiction between slow steady addition and fast production.
Solution Approach 2:
The patent implements feedback control by monitoring copolymer composition during the metering process and adjusting the acid monomer addition rate accordingly. This closed-loop control ensures that composition uniformity is maintained even at higher metering rates, thereby improving both precision and productivity simultaneously.
2Ease of operation
If excess mixing water is added to achieve desired processing consistency, then processability is improved, but mechanical strength and stability of concrete deteriorate
Solution Approach 1:
The patent changes the chemical parameter of the dispersant (copolymer composition) to achieve better dispersing efficiency at lower concentrations. By optimizing the copolymer structure through controlled metering, the system reduces the amount of water needed for processing while maintaining or improving mechanical strength, thus resolving the contradiction between processability and strength.
3Reliability
If conventional semibatch copolymerization is used to produce superplasticizers, then dispersant performance is achieved, but cost-efficiency and production speed deteriorate
Solution Approach 1:
The patent transforms the conventional semibatch process into a more continuous operation by implementing automated metering and control systems. This continuous operation reduces idle time, optimizes resource utilization, and maintains consistent dispersant performance while significantly improving production speed and cost-efficiency.
Solution Approach 2:
The patent optimizes key process parameters including metering rate, temperature, and monomer ratios to achieve the desired dispersant performance more efficiently. By carefully controlling these parameters, the system maintains high product quality while reducing production time and costs.
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 results in a high-quality copolymer with improved water reduction and retention of processability, allowing for increased production capacity and cost-efficiency by reducing reaction times and improving the uniformity of comonomer distribution in the polymer chain.
Implementation Method 1
free radical polymerization initiator being passed into the polymerization reactor before and/or during the metering of the acid monomer into the polymerization reactor so that an aqueous medium in which acid monomer and polyether macromonomer are reacted with formation of the copolymer by free radical polymerization forms in the polymerization reactor
Data Source
AI summary
A process for the preparation of a copolymer in semicontinuous operation in a polymerization apparatus, comprising a polymerization reactor connected to a metering device, acid monomer being initially taken in the metering device and polyether macromonomer, acid monomer and water in the polymerization reactor, acid monomer being metered from the metering device into the polymerization reactor, the metering of the acid monomer being effected with the proviso that at least 70 mol % of the acid monomer metered in altogether are metered in the course of 5 to 19 minutes at a metering rate that is constant or varies to a limited extent.