Chloroprene Rubber Low-Temperature Properties via Monomer Control
Solution Overview
Problem
Chloroprene rubbers exhibit poor low-temperature properties, particularly in compression set and dynamic properties, which are not effectively improved by traditional methods that modify blending technology, as increased amounts of softening agents lead to bleeding and reduced adhesiveness.
Innovation Solution
Incorporating antiperiplanar trans-1-chlorobuta-1,3-diene and cis-1-chlorobuta-1,3-diene in a total amount of 0.5 mass % or more, along with 2,3-dichlorobuta-1,3-diene in an amount of 2.0 mass % or more, during emulsion polymerization to enhance the low-temperature properties of chloroprene rubber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the amount of softening agent is increased to improve low-temperature properties, then low-temperature resistance is improved, but softening agent bleeding occurs and adhesiveness deteriorates
Solution Approach 1:
The invention changes the chemical composition parameters of the rubber polymer itself by controlling the content of specific monomers (1-chlorobuta-1,3-diene isomers and 2,3-dichlorobuta-1,3-diene) during polymerization, rather than changing the amount of softening agent added. This internal modification of the polymer structure improves low-temperature properties without causing bleeding or adhesion issues.
Solution Approach 2:
The invention extracts the function of improving low-temperature properties from the softening agent and transfers it to the rubber polymer itself through controlled monomer composition. This eliminates the need for high amounts of softening agents that cause bleeding, as the polymer's inherent structure provides the low-temperature performance.
2Temperature
If traditional blending technology is modified to improve low-temperature properties, then low-temperature resistance is improved, but the complexity of the formulation increases
Solution Approach 1:
The invention extracts the low-temperature improvement function from the blending process and incorporates it directly into the polymer synthesis process through controlled monomer selection. This eliminates the need for complex blending formulations and multiple additives, simplifying the overall technology while achieving the same performance improvement.
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 resulting chloroprene rubber composition demonstrates improved low-temperature properties, including enhanced crystallization resistance and compression set, without the drawbacks of softening agent bleeding, leading to more stable and effective vulcanizates and formed bodies.
Implementation Method 1
a product obtained by emulsion polymerization of raw monomers containing antiperiplanar trans-1-chlorobuta-1,3-diene and cis-1-chlorobuta-1,3-diene in a total amount of 0.5 mass % or more and, 2,3-dichlorobuta-1,3-diene in an amount of 2.0 mass % or more
Data Source
AI summary
Provided are a chloroprene rubber, a chloroprene rubber composition and the vulcanizate and formed body thereof superior in low-temperature properties.A chloroprene rubber is obtained by emulsion polymerization of raw monomers containing antiperiplanar trans-1-chlorobuta-1,3-diene and cis-1-chlorobuta-1,3-diene in a total amount of 0.5 mass % or more, 2,3-dichlorobuta-1,3-diene in an amount of 2.0 mass % or more, and the rest being chloroprene. A composition containing the chloroprene is vulcanized into a formed body.