Chloroprene-Nitrile Statistical Copolymer Feed Control for Oil Resistance
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Solution Overview
Problem
The existing methods for copolymerizing chloroprene and unsaturated nitrile compounds face challenges in achieving sufficient oil resistance and dynamic properties, particularly due to reactivity differences between chloroprene and acrylonitrile, leading to inadequate performance in applications such as power transmission belts and hoses.
Innovation Solution
A method involving continuous or intermittent addition of chloroprene monomer during polymerization, maintaining a target ratio of unreacted monomers to ensure consistent polymerization, with the addition of a xanthic compound as a chain transfer agent, to produce a statistical copolymer with improved oil resistance and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chloroprene and unsaturated nitrile are copolymerized using conventional methods, then polymerization can proceed, but the oil resistance is insufficient due to inadequate acrylonitrile copolymerization quantity
Solution Approach 1:
The patent applies preliminary action by adding a chain transfer agent (xanthic compound) before polymerization begins. This agent pre-establishes conditions that promote acrylonitrile incorporation into the copolymer chain, ensuring sufficient acrylonitrile copolymerization quantity from the start of the reaction, which directly improves oil resistance.
Solution Approach 2:
The patent changes key polymerization parameters including using a specific chain transfer agent (xanthic compound) at controlled concentrations (0.01-5 wt% based on total monomer), maintaining specific temperature ranges (5-50°C), and controlling monomer feed ratios. These parameter changes optimize the copolymerization process to achieve both high acrylonitrile incorporation and satisfactory oil resistance.
2Quantity of substance
If chloroprene is added portionwise to maintain high acrylonitrile concentration, then acrylonitrile copolymerization quantity increases, but the process complexity increases
Solution Approach 1:
The patent extracts the function of controlling monomer composition from the complex portionwise addition process by using a chain transfer agent instead. This eliminates the need for multiple addition steps and complex monitoring systems, simplifying the process while maintaining high acrylonitrile copolymerization quantity through the chemical action of the xanthic compound.
Solution Approach 2:
The xanthic compound acts as an intermediary that mediates the polymerization process. Rather than directly controlling monomer addition rates and timing, the chain transfer agent indirectly influences copolymer composition by controlling chain growth and termination, thereby simplifying the overall process complexity while achieving the desired acrylonitrile incorporation.
3Reliability
If conventional copolymerization methods are used, then production can proceed, but dynamic properties such as compression set and flex fatigue resistance are insufficient
Solution Approach 1:
The patent optimizes multiple manufacturing parameters simultaneously: using xanthic compound as chain transfer agent at specific concentrations (0.01-5 wt%), controlling polymerization temperature (5-50°C), and adjusting monomer ratios. These coordinated parameter changes produce copolymers with improved dynamic properties (compression set ≤50%, flex fatigue resistance ≥100,000 cycles) while maintaining manufacturing simplicity through a single-step process.
4Stability of the object's composition
If the reactivity difference between chloroprene and acrylonitrile is not addressed, then polymerization is simple, but the copolymer composition is inconsistent
Solution Approach 1:
The patent implements feedback control through the chain transfer agent mechanism. The xanthic compound continuously interacts with growing polymer chains, regulating monomer incorporation based on instantaneous composition. This self-regulating feedback ensures consistent copolymer composition throughout the reaction without requiring complex external monitoring and adjustment systems.
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 produces a statistical copolymer with enhanced oil resistance, compression set, and flex fatigue resistance, meeting requirements for applications like power transmission belts and hoses, with improved mechanical characteristics such as tensile strength and elongation at break.
Implementation Method 1
a method involving continuous or intermittent addition of chloroprene monomer during polymerization, maintaining a target ratio of unreacted monomers to ensure consistent polymerization, with the addition of a xanthic compound as a chain transfer agent
Implementation Method 2
a step for conducting continuous addition of the chloroprene monomer after initiation of a polymerization reaction
Data Source
AI summary
To provide a statistical copolymer containing a chloroprene monomer unit and an unsaturated nitrile monomer unit which has a satisfactory oil resistance. A method for producing a statistical copolymer containing a chloroprene monomer unit and an unsaturated nitrile monomer unit comprising a step for conducting continuous addition or 10 cycles or more of intermittent portionwise addition of the chloroprene monomer after initiation of a polymerization reaction is provided. A rubber composition using a statistical copolymer according to the invention or a vulcanized molded article containing said rubber composition is excellent in terms of oil resistance, mechanical strength, compression set at a low temperature and flex fatigue resistance.