Crosslinked Acrylic Rubber Composition for Deteriorated Engine Oil
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Solution Overview
Problem
Acrylic rubber materials used in automotive seal and hose parts face deterioration due to severe thermal environments and exposure to deteriorated engine oil, requiring enhanced heat aging, oil, cold, and deteriorated engine oil resistance.
Innovation Solution
A crosslinked acrylic rubber composition with specific monomer unit ratios, including acrylate, methacrylate, and crosslinkable monomers with a carboxyl group, optimized for glass transition temperature and resistance tests, ensuring excellent heat aging, oil, and deteriorated engine oil resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional acrylic rubber compositions are used, then basic rubber properties are maintained, but resistance to deteriorated engine oil and heat aging deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the glass transition temperature (Tg) to be -20°C or lower and adjusting the monomer composition ratios (acrylate units: 60-80 wt%, methacrylate units: 10-40 wt%, crosslinkable monomer units: 1-30 wt%). These parameter optimizations enable the rubber to maintain flexibility at low temperatures while achieving superior resistance to deteriorated engine oil and heat aging through the specific molecular structure and crosslinking density.
Solution Approach 2:
The patent employs composite materials by creating a crosslinked acrylic rubber composed of multiple monomer units with different functions: acrylate units providing base elasticity, methacrylate units enhancing oil resistance, and crosslinkable monomer units forming the crosslinked network structure. This composite approach at the molecular level achieves synergistic effects that improve overall durability against thermal and chemical degradation.
2Temperature
If crosslinked acrylic rubber is used for seal and hose parts, then oil resistance and heat aging resistance are improved, but cold resistance and deteriorated engine oil resistance deteriorate under severe thermal environments
Solution Approach 1:
The patent resolves this contradiction by setting the glass transition temperature (Tg) at -20°C or lower, which ensures cold resistance while maintaining heat aging resistance. The specific monomer composition ratios are optimized to balance thermal stability with low-temperature flexibility, allowing the rubber to perform reliably across extreme temperature ranges and in contact with deteriorated engine oil.
3Reliability
If glass transition temperature is lowered to improve cold resistance, then oil resistance and heat aging resistance may deteriorate
Solution Approach 1:
The patent achieves the optimal balance by setting Tg at -20°C or lower while carefully controlling the monomer composition. The presence of crosslinkable monomer units (1-30 wt%) and methacrylate units (10-40 wt%) ensures that even with low Tg for cold resistance, the crosslinked structure provides sufficient heat aging resistance and oil resistance, preventing the deterioration that would normally occur with low-Tg rubbers.
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 solution provides crosslinked acrylic rubber with improved heat aging, oil, and deteriorated engine oil resistance while maintaining mechanical properties like tensile strength and elongation.
Implementation Method 1
a crosslinked acrylic rubber formed by crosslinking an acrylic rubber composition containing an acrylic rubber
Implementation Method 2
a glass transition temperature Tg of the acrylic rubber, obtained by measuring the acrylic rubber from -80°C to -50°C at a rate of 10°C/min using a differential scanning calorimeter
Data Source
AI summary
The present invention relates to an acrylic rubber containing acrylate monomer units, methacrylate monomer units, and crosslinkable monomer units, wherein a glass transition temperature is -20°C or less, a change ratio in volume after a crosslinked rubber of the acrylic rubber is immersed in IRM903 oil at 150±2°C for 72 hours is 0 to 100%, and a change ratio in weight after a crosslinked rubber of the acrylic rubber is immersed in hot water at 150±2°C for 96 hours and dried is -5.0 to 0%.