Highly Saturated Nitrile Rubber Composition for Automotive Seals
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Solution Overview
Problem
Existing nitrile rubber compositions for automotive applications face challenges in achieving excellent rollability, normal physical properties, oil resistance, fuel oil resistance, and tensile strength under high temperatures, particularly in cross-linked rubber products such as seals, gaskets, and hoses.
Innovation Solution
A highly saturated nitrile rubber composition is developed by blending a carboxyl group-containing highly saturated nitrile rubber with a specific ratio of α,β-ethylenically unsaturated dicarboxylic acid monoester monomer units and a polyamide resin, which is then cross-linked using an organic peroxide cross-linking agent, enhancing the rubber's properties through a twin screw extrusion process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a hydrogenated NBR elastomer matrix with dispersed Nylon microparticles and functional group-containing ethylene-based copolymer is used, then normal physical properties are improved, but rollability deteriorates and oil resistance, fuel oil resistance, and tensile strength under high temperature become inferior
Solution Approach 1:
The patent applies parameter changes by carefully controlling the content of α,β-ethylenically unsaturated dicarboxylic acid monoester monomer units (0.1-10 mol%) and the ratio of highly saturated nitrile rubber to polyamide resin (95:5 to 50:50 by weight). These parameter adjustments optimize the balance between rollability and cross-linking reactivity, resolving the contradiction between ease of processing and final product performance
Solution Approach 2:
The patent uses composite materials by combining highly saturated nitrile rubber with polyamide resin and functional group-containing ethylene-based copolymer in specific ratios. This composite approach allows the material to achieve both good rollability (from the rubber matrix) and excellent oil resistance and high-temperature strength (from the cross-linked composite structure)
2Ease of operation
If the same rubber composition is used, then rollability is improved, but oil resistance, fuel oil resistance, and tensile strength under high temperature become inferior
Solution Approach 1:
The patent optimizes parameters by controlling the dicarboxylic acid monoester monomer content (0.1-10 mol%) and the highly saturated nitrile rubber to polyamide resin ratio (95:5 to 50:50 by weight). These parameter adjustments ensure sufficient cross-linking density for reliable oil and fuel resistance while maintaining good rollability during processing
Solution Approach 2:
The composite material system combines highly saturated nitrile rubber with polyamide resin and functional group-containing ethylene-based copolymer. This composite structure provides both the processability needed for good rollability and the chemical resistance required for reliable oil and fuel resistance along with high-temperature strength
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 cross-linked rubber exhibits improved rollability, normal physical properties, oil resistance, fuel oil resistance, and tensile strength under high temperatures, while maintaining suitable hardness and workability, making it suitable for various automotive components.
Implementation Method 1
cross-linked using an organic peroxide cross-linking agent
Implementation Method 2
twin screw extrusion process
Data Source
AI summary
A highly saturated nitrile rubber composition containing a carboxyl group-containing highly saturated nitrile rubber (A1) which contains α,β-ethylenically unsaturated nitrile monomer units 15 to 60 wt % and α,β-ethylenically unsaturated dicarboxylic acid monoester monomer units 1 to 60 wt % and has an iodine value of 120 or less, a highly saturated nitrile rubber (A2) which contains α,β-ethylenically unsaturated nitrile monomer units 15 to 60 wt %, has a content of the α,β-ethylenically unsaturated dicarboxylic acid monoester monomer units of 0.9 wt % or less, and has an iodine value of 120 or less, and a polyamide resin (B), a content ratio of the carboxyl group-containing highly saturated nitrile rubber (A1) and the highly saturated nitrile rubber (A2) being a weight ratio of “carboxyl group-containing highly saturated nitrile rubber (A1):highly saturated nitrile rubber (A2)” of 2:98 to 98:2, is provided.