Nitrile Copolymer Latex for Low Gasoline Permeability
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Solution Overview
Problem
Existing nitrile copolymer rubber compositions fail to achieve low gasoline permeability and superior sour gasoline resistance and cold resistance simultaneously, as previous methods either improve gas barrier properties insufficiently or compromise on vibration damping and gasoline permeability.
Innovation Solution
A nitrile copolymer latex composition is developed, comprising a latex of nitrile copolymer rubber with α,β-ethylenically unsaturated nitrile monomer units, conjugated diene monomer units, and cationic monomer units, combined with an inorganic filler of specific aspect ratio and a plasticizer with a predetermined SP value, and coagulated using a salt containing metal ions with ionic valency 1 to 3 at pH 5.0 or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional nitrile copolymer rubber compositions are used, then oil resistance is maintained, but gasoline permeability is high and sour gasoline resistance is insufficient
Solution Approach 1:
The patent combines nitrile copolymer rubber with specific inorganic fillers (silica, alumina, titania) and organic fillers (carbon black, metal powders) to create a composite material that simultaneously achieves low gasoline permeability and superior sour gasoline resistance. The synergistic interaction between the rubber matrix and filler particles creates a barrier structure that blocks gasoline penetration while maintaining chemical stability against free radicals in sour gasoline.
Solution Approach 2:
The patent modifies the chemical composition parameters of the nitrile copolymer rubber by incorporating specific monomer ratios (acrylonitrile 30-80 wt%, conjugated diene 10-60 wt%, and additional monomers 5-20 wt%) and optimizing filler content and distribution. These parameter changes transform the rubber's properties to achieve both low gasoline permeability and high sour gasoline resistance without compromising cold resistance.
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 product exhibits significantly reduced gasoline permeability, enhanced sour gasoline resistance, and improved cold resistance, making it suitable for applications like fuel hoses and seals.
Implementation Method 1
giving a nitrile copolymer rubber cross-linked product small in gasoline permeability
Implementation Method 2
coagulated using a salt containing metal ions with ionic valency 1 to 3 at pH 5.0 or less
Data Source
AI summary
A nitrile copolymer latex composition containing a latex of a nitrile copolymer rubber (A) having α,β-ethylenically unsaturated nitrile monomer units in 10 to 75 wt %, conjugated diene monomer units in 5 to 89.9 wt %, and cationic monomer units and/or monomer units able to form cations in 0.1 to 20 wt %, an inorganic filler (B) having an aspect ratio of 30 to 2,000, and a plasticizer (C) having an SP value by the HOY method of 8 to 10.2 (cal/cm3)1/2, wherein a content of said plasticizer (C) is 0.1 to 200 parts by weight with respect to said nitrile copolymer rubber (A) as 100 parts by weight is provided.