EPDM Rubber Rigidity Stability High Temperature
Solution Overview
Problem
High rigidity rubber materials used in rubber hoses and products lose rigidity at high temperatures, making them ineffective in high temperature regions despite using carbon black and thermoplastic resins for increased rigidity at ordinary temperatures.
Innovation Solution
A rubber material composition comprising EPDM rubber, carbon black, a softening agent, a vulcanizing agent, and a sulfur compound, with specific blending ratios and amounts, including a sulfur content that maintains rigidity across a wide temperature range from 20°C to 110°C, ensuring a minimal rate of rigidity change.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If carbon black is increased as a reinforcing agent to increase rigidity of rubber materials, then rigidity in ordinary temperature region is improved, but rigidity in high temperature region becomes ineffective
Solution Approach 1:
The patent changes the chemical composition parameters of the rubber material by incorporating specific ratios of EPDM rubber (40-70 parts), carbon black (135-180 parts), and softening agent (55-100 parts) to achieve rigidity that remains effective across both ordinary and high temperature regions, resolving the temperature dependence issue
Solution Approach 2:
The patent creates a composite rubber material system combining EPDM rubber with carbon black and softening agent in specific proportions, where the synergistic interaction between components maintains rigidity at both ordinary and high temperatures, overcoming the limitation of carbon black alone
2Strength
If thermoplastic resin is added to increase rigidity of rubber materials, then rigidity in ordinary temperature region is improved, but rigidity in high temperature region becomes ineffective
Solution Approach 1:
The patent modifies the material composition by replacing thermoplastic resin with a specific combination of EPDM rubber, carbon black, and softening agent, where the vulcanized rubber matrix maintains structural integrity and rigidity at high temperatures unlike thermoplastic resins
3Strength
If high amount of carbon black is blended with EPDM rubber to increase rigidity, then rigidity is improved, but stress characteristics for thin-walled products cannot be obtained
Solution Approach 1:
The patent optimizes the carbon black content to a specific range (135-180 parts per 100 parts EPDM) and adjusts the softening agent content (55-100 parts) to achieve the right balance between rigidity and stress characteristics, enabling both high rigidity and good stress performance in thin-walled products
Solution Approach 2:
The patent creates different local properties within the rubber material by controlling the distribution and interaction of carbon black reinforcement and softening agent, where the matrix provides flexibility for stress characteristics while the reinforcement provides rigidity
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 rubber material maintains high rigidity and a small rate of rigidity change across a wide temperature range, effectively addressing the loss of rigidity at high temperatures, suitable for applications like automotive parts that experience high temperatures.
Implementation Method 1
a rubber material containing an EPDM rubber composition, in which the EPDM rubber composition contains an EPDM rubber, a carbon black, a softening agent, a vulcanizing agent, and a sulfur compound
Data Source
AI summary
The present invention relates to a rubber material containing an EPDM rubber composition containing an EPDM rubber, a carbon black, a softening agent, a vulcanizing agent and a sulfur compound, in which a blending amount of whole components from which the vulcanizing agent and the sulfur compound are excluded is from 300 to 400 parts by weight, and a total sulfur blending amount is from 1.0 to 2.8 parts by weight, in which a blending ratio of carbon black/softening agent is from 1.8 to 2.5, and in which the EPDM rubber composition has a Mooney viscosity of from 70 to 100 at 100° C., and a vulcanized composition thereof has a rate of rigidity change satisfying the following equation (1):{(30% Modulus at 100° C./30% modulus at 23° C.)−1}×100%≧−10% (1).