Acrylic Rubber Copolymer Heat Aging Resistance
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Solution Overview
Problem
Acrylic rubber compositions face challenges in maintaining tensile strength and elongation at break after heat aging, which affects their heat resistance and mechanical properties, especially in high-temperature engine applications.
Innovation Solution
Copolymerizing alkyl acrylate with alkyl methacrylate and a crosslinkable monomer having an epoxy group, such as glycidyl methacrylate, to create an acrylic rubber that can be vulcanized with additional components like vulcanizers and antioxidants, enhancing heat resistance without compromising normal state physical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If acrylic rubber is used in engine room components, then it provides good oil resistance and mechanical properties, but heat resistance is insufficient for high-temperature applications
Solution Approach 1:
The patent changes the chemical composition parameters of acrylic rubber by incorporating specific ratios of alkyl acrylate (100 parts) and alkyl methacrylate (10-100 parts), along with a crosslinkable monomer having an epoxy group (0.5-4 parts). This compositional parameter change enables the rubber to maintain tensile strength above 80% after heat aging at 150°C for 228 hours, resolving the heat resistance issue while maintaining reliability
Solution Approach 2:
The patent creates a composite acrylic rubber system by combining multiple monomer units (alkyl acrylate and alkyl methacrylate) with a crosslinkable monomer containing epoxy groups. This composite structure at the molecular level provides both the base rubber's oil resistance and the crosslinked network's heat resistance, achieving superior performance in high-temperature engine room applications
2Temperature
If acrylic rubber is heat treated to improve heat resistance, then temperature tolerance increases, but tensile strength and elongation at break deteriorate
Solution Approach 1:
The patent applies preliminary action by incorporating a crosslinkable monomer with epoxy groups into the acrylic rubber composition before heat aging occurs. This pre-established crosslinking capability allows the rubber to form a stable three-dimensional network structure during controlled vulcanization, preventing the degradation of tensile strength and elongation at break that would normally occur during heat treatment
Solution Approach 2:
The patent utilizes parameter changes by controlling the amount of crosslinkable monomer (0.5-4 parts per 100 parts of alkyl acrylate) and the vulcanization conditions. This precise parameter control enables the rubber to achieve adequate crosslinking for heat resistance while maintaining tensile strength above 80% and acceptable elongation at break after heat aging
3Reliability
If crosslinking is increased to improve heat aging resistance, then heat resistance improves, but normal state physical properties are impaired
Solution Approach 1:
The patent applies parameter changes by optimizing the concentration of the crosslinkable monomer with epoxy groups to a specific range (0.5-4 parts per 100 parts of alkyl acrylate). This controlled parameter adjustment ensures sufficient crosslinking for heat aging resistance while preventing excessive crosslinking that would degrade normal state physical properties such as flexibility and processability
Solution Approach 2:
The patent applies local quality by creating a controlled crosslinked network structure within the acrylic rubber matrix. The crosslinking is distributed uniformly at an optimal density, providing local reinforcement for heat resistance while maintaining the overall flexibility and physical properties of the rubber in its normal state
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 vulcanized products exhibit improved heat aging resistance with minimal change in tensile strength and elongation at break, maintaining excellent mechanical properties even after exposure to high temperatures.
Implementation Method 1
copolymerizing 100 parts by mass of an alkyl acrylate with from 10 to 100 parts by mass of an alkyl methacrylate and from 0.5 to 4 parts by mass of a crosslinkable monomer having an epoxy group
Data Source
AI summary
To provide an acrylic rubber composition having an excellent heat resistance, especially an excellent balance between the residual ratio of the tensile strength and the residual ratio of the elongation after heat aging, when formed into a vulcanized product, and a hose article, a sealing article and a rubber vibration insulator using the acrylic rubber composition. An acrylic rubber composition containing an acrylic rubber obtainable by copolymerizing 100 parts by mass of an alkyl acrylate with from 10 to 100 parts by mass of an alkyl methacrylate and from 0.5 to 4 parts by mass of a crosslinkable monomer. Here, the alkyl methacrylate is preferably at least one compound selected from the group consisting of methyl methacrylate, ethyl methacrylate and n-butyl methacrylate, and the alkyl acrylate is preferably at least one compound selected from the group consisting of methyl acrylate, ethyl acrylate and n-butyl acrylate.