Nitrile Copolymer Rubber Composition for Fuel Hose Applications
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Solution Overview
Problem
Current nitrile copolymer rubber compositions, while offering improved gasoline permeation resistance and cold resistance, still fall short in meeting the enhanced mechanical property demands for applications such as fuel hoses, seals, and packings, particularly in terms of tensile strength and fatigue resistance.
Innovation Solution
A nitrile copolymer rubber composition comprising α,β-ethylenically unsaturated nitrile monomer units, conjugated diene monomer units, and α,β-ethylenically unsaturated carboxylic acid monomer units in specific ratios, combined with an inorganic filler of aspect ratio 30 to 2,000, and optionally a vinyl chloride resin or acrylic resin, to create a cross-linkable composition that maintains original state physical properties while enhancing gasoline permeation resistance and cold resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a nitrile copolymer rubber composition containing cationic monomer units and flat-shaped inorganic filler is used to improve gasoline permeation resistance, then gasoline permeation resistance is improved to a certain degree, but mechanical properties such as tensile strength and fatigue resistance deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters by introducing α,β-ethylenically unsaturated carboxylic acid monomer units (a3) at 0.5 to 20 wt% in addition to the nitrile monomer units (a1) and conjugated diene units (a2). This compositional parameter change modifies the rubber matrix properties to simultaneously achieve good mechanical strength and improved gasoline permeation resistance when combined with flat-shaped inorganic filler.
Solution Approach 2:
The patent creates a composite material system by combining the nitrile copolymer rubber (A) with specific compositional ratios of three types of monomer units and flat-shaped inorganic filler (B) with aspect ratio of 30 to 2,000. The synergistic interaction between the carboxylic acid groups in the rubber and the inorganic filler creates a composite structure that maintains mechanical properties while blocking gasoline permeation pathways.
2Reliability
If the nitrile copolymer rubber composition is optimized for gasoline permeation resistance, then resistance to gasoline permeation is improved, but cold resistance deteriorates
Solution Approach 1:
The patent carefully balances the compositional parameters by limiting the carboxylic acid monomer content to 0.5 to 20 wt% and optimizing the ratio between nitrile units (35 to 80 wt%), conjugated diene units (19.5 to 64.5 wt%), and carboxylic acid units. This parameter optimization ensures the rubber maintains flexibility and cold resistance while achieving improved gasoline permeation resistance through the synergistic effect with flat-shaped inorganic filler.
Data Source
AI summary
A nitrile copolymer rubber composition including a nitrile copolymer rubber (A) containing 35 to 80 wt % of α,β-ethylenically unsaturated nitrile monomer units (a1), 19.5 to 64.5 wt % of conjugated diene monomer units (a2), and 0.5 to 20 wt % of α,β-ethylenically unsaturated carboxylic acid monomer units (a3) and an inorganic filler (B) with an aspect ratio of 30 to 2,000, wherein a content of the inorganic filler (B) with respect to 100 parts by weight of the nitrile copolymer rubber (A) is 1 to 200 parts by weight is provided.