Acrylic Rubber Copolymer with Ether Side Chains for Cold Resistance
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Solution Overview
Problem
Current acrylic rubber compositions face challenges in maintaining oil resistance while improving cold resistance, particularly in extremely cold conditions, with existing solutions either compromising oil resistance or failing to achieve desired cold resistance levels.
Innovation Solution
A copolymer composition of 1 to 3 wt.% fumaric acid monoalkyl ester, 45 to 65 wt.% n-butyl acrylate, 12 to 32 wt.% 2-methoxyethyl acrylate, and 11 to 30 wt.% ethoxyethoxyethyl acrylate, compounded with an aromatic diamine vulcanizing agent, which improves cold resistance without significantly reducing oil resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the alkyl chain is merely extended to improve cold resistance, then cold resistance is improved, but oil swelling resistance overly increases
Solution Approach 1:
The patent changes the chemical structure parameters by introducing ether bonds into the side chain of the acrylic rubber monomer. Specifically, it uses alkoxyalkyl acrylates (containing C-O-C ether bonds) instead of simple alkyl acrylates. This structural parameter change allows the material to achieve both improved cold resistance (TR-10 value of -45°C or lower) and maintained oil swelling resistance (within 50% volume increase in industrial oil at 100°C for 70 hours), resolving the contradiction between these two properties.
Solution Approach 2:
The patent creates a composite molecular structure by combining acrylic rubber with ether-containing side chains (alkoxyalkyl acrylate units) in a copolymer system. This composite approach at the molecular level integrates the cold-resistant properties of ether bonds with the elastomeric properties of acrylic rubber, achieving a material that simultaneously provides excellent cold resistance and oil resistance that cannot be obtained with simple alkyl chain extension alone.
2Reliability
If acrylic rubber is used as an oil seal molding material, then oil resistance is maintained, but use in extremely cold areas is difficult due to insufficient cold resistance
Solution Approach 1:
The patent modifies the molecular structure parameters of acrylic rubber by incorporating 5-50 mol% of alkoxyalkyl acrylate units (containing ether bonds) into the polymer chain. This structural modification lowers the glass transition temperature (Tg) to -50°C or lower, achieving TR-10 values of -45°C or lower, while maintaining oil resistance characteristics. This enables the material to function as an oil seal molding material in extremely cold environments down to -45°C.
3Temperature
If a methoxy triethylene glycol ester is used to improve cold resistance, then cold resistance is improved, but tensile strength and elongation at break are deteriorated
Solution Approach 1:
The patent optimizes the compositional parameters by controlling the content of alkoxyalkyl acrylate units within 5-50 mol% of the total monomer composition. This parameter optimization balances the competing requirements: sufficient ether bond content to achieve the desired cold resistance (Tg ≤ -50°C) while limiting the concentration to maintain adequate tensile strength (≥5 MPa) and elongation at break (≥100%). This compositional control prevents the deterioration of mechanical properties while achieving the target cold resistance.
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 a reduced TR-10 value of -41.0°C or lower, enhancing cold resistance while maintaining adequate oil resistance and compression set resistance characteristics.
Implementation Method 1
copolymer rubber of alkyl (meth)acrylate and (meth)acrylate having an ether group forming a side chain is used as the acrylic rubber
Data Source
AI summary
An acrylic rubber that is a copolymer in which 1 to 3 wt.% of a fumaric acid monoalkyl ester monomer containing an alkyl group having 1 to 8 carbon atoms is copolymerized as a crosslinkable comonomer, wherein 45 to 65 wt.% of n-butyl acrylate, 12 to 32 wt.% of 2-methoxyethyl acrylate, and 11 to 30 wt.% of ethoxyethoxyethyl acrylate are copolymerized in 100 wt.% of comonomers other than the crosslinkable comonomer. This acrylic rubber can suppress the reduction of oil resistance while improving cold resistance represented by a TR-10 value.