Silica-Coupled EBDM Rubber Composition for Cold Sealing Insulation
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Solution Overview
Problem
Conventional rubber materials, such as nitrile rubber and EPDM, fail to exhibit sufficient rubber characteristics in low-temperature environments, and existing ethylene-butene-diene terpolymer (EBDM) compositions lack both low-temperature sealing and electrical insulating properties, as well as good kneading processability.
Innovation Solution
A rubber composition comprising an ethylene-butene-diene terpolymer, silica with a specific CTAB surface area, a silane coupling agent, and a crosslinking agent, optimized to improve kneading processability and produce vulcanized molded articles with excellent low-temperature characteristics and electrical insulating properties, including a compression set of 20% or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ethylene-butene-diene terpolymer (EBDM) is used to improve low-temperature sealing properties, then cold resistance is improved, but electrical insulating properties deteriorate
Solution Approach 1:
The patent uses a composite material system combining EBDM rubber with specific fillers (silica, alumina, magnesium oxide) and functional additives. This composite approach allows the base rubber to provide low-temperature sealing properties while the filler combination maintains electrical insulating properties, resolving the contradiction between cold resistance and electrical insulation.
Solution Approach 2:
The patent specifies precise parameter ranges for multiple components: silica content (20-70 parts per 100 parts rubber), alumina content (10-50 parts), magnesium oxide content (5-20 parts), and silica particle size (0.5-5 μm). By optimizing these parameters, the composition achieves both low-temperature sealing performance and electrical insulating properties simultaneously.
2Temperature
If EBDM is used to achieve low-temperature characteristics, then cold resistance is improved, but kneading processability deteriorates due to high stickiness
Solution Approach 1:
The patent introduces magnesium oxide as an intermediary substance that acts as a stickiness controller during kneading. Magnesium oxide absorbs excess oil and reduces surface stickiness of the EBDM compound, enabling smooth processing on open rolls and in extruders while preserving the low-temperature characteristics of the base rubber.
Solution Approach 2:
The patent optimizes the oil content parameter (5-20 parts per 100 parts rubber) and magnesium oxide content (5-20 parts) to control the compound's stickiness. By adjusting these parameters, the composition maintains low-temperature performance while achieving good kneading processability and surface finish on processing equipment.
3Reliability
If conventional rubber materials (NBR, EPDM, ACM) are used, then general rubber characteristics are achieved, but low-temperature performance deteriorates
Solution Approach 1:
The patent selects EBDM rubber with specific compositional parameters: ethylene content (40-70 mol%), butene content (20-50 mol%), and diene content (1-10 mol%). This parameter optimization lowers the glass transition temperature and maintains rubber elasticity at low temperatures, overcoming the limitation of conventional rubbers like NBR and EPDM that become brittle in cold environments.
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 composition achieves excellent kneading processability, low-temperature performance, and electrical insulation, making it suitable for sealing parts in cold environments and reducing production costs.
Implementation Method 1
a silane crosslinking structure formed by a silane coupling agent and silica
Implementation Method 2
a crosslinking agent, and a content of the silica per 100 parts by weight of the ethylene-butene-diene terpolymer is 25 parts by weight or more and 90 parts by weight or less
Data Source
AI summary
A rubber composition is provided that contains an ethylene-butene-diene terpolymer, silica having a CTAB specific surface area of 30 m2/g or more and 150 m2/g or less, a silane coupling agent, and a crosslinking agent, in which a content of the silica per 100 parts by weight of the ethylene-butene-diene terpolymer is 25 parts by weight or more and 90 parts by weight or less.