Polyurethane Barrier Coating for Fuel Vessels
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Solution Overview
Problem
Fuel vessels and molded parts in vehicles face challenges with gasoline permeability, heat resistance, and impact resistance, leading to fuel leakage and unsatisfactory performance under stringent environmental regulations.
Innovation Solution
A fuel system is developed with a high gasoline-barrier coating layer formed by curing a polyurethane resin composition comprising active hydrogen-containing compounds and organic polyisocyanate compounds on thermoplastic resin or rubber components, enhancing adhesion, flexibility, bending resistance, and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a polyethylene-single layer type tank is used, then ease of manufacture and cost are improved, but gasoline barrier property deteriorates
Solution Approach 1:
The patent applies composite materials by creating a multilayer structure consisting of polyethylene layers and EVOH (ethylene-vinyl alcohol copolymer) barrier layers. This composite structure combines the manufacturing advantages of polyethylene with the superior gasoline barrier properties of EVOH, resolving the contradiction between ease of manufacture and gasoline barrier property.
2Reliability
If a multilayer tank comprising polyethylene and EVOH is used, then gasoline barrier property is improved, but heat resistance and impact resistance deteriorate
Solution Approach 1:
The patent applies local quality by strategically placing EVOH barrier layers only at specific positions where gasoline permeation is most critical (such as at connections and interfaces), while maintaining polyethylene structure in areas requiring heat and impact resistance. This localized application of barrier material optimizes gasoline barrier property without compromising overall structural strength.
3Reliability
If barrier resin (EVOH) is used for molded parts, then gasoline barrier property is improved, but heat fusing property and mechanical strength deteriorate
Solution Approach 1:
The patent applies local quality by forming a barrier resin coating layer only on the inner surface or specific areas of molded parts that contact fuel, while the bulk material remains as high-density polyethylene with good heat fusing and mechanical properties. This localized coating approach provides gasoline barrier protection without sacrificing the heat fusing and strength characteristics of the base material.
Solution Approach 2:
The patent applies composite materials by combining a thin barrier resin coating layer with the bulk polyethylene structure of molded parts. This composite construction provides both the gasoline barrier properties of EVOH and the heat fusing and mechanical strength of polyethylene, resolving the contradiction between barrier performance and structural properties.
4Ease of operation
If conventional rubber material tubes are used, then flexibility and ease of installation are improved, but fuel permeation resistance deteriorates
Solution Approach 1:
The patent applies composite materials by creating a laminated tube structure with an inner layer of barrier resin (such as polyamide or EVOH) and an outer layer of rubber material. The inner barrier layer provides fuel permeation resistance while the outer rubber layer maintains flexibility and ease of installation, resolving the contradiction between these two properties.
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 solution significantly reduces gasoline permeability, improves adhesion between vessel and molded parts, and provides excellent flexibility, bending resistance, and heat resistance, effectively addressing the limitations of existing technologies.
Implementation Method 1
a high gasoline-barrier coating layer formed by curing a polyurethane resin composition comprising active hydrogen-containing compounds and organic polyisocyanate compounds
Implementation Method 2
improves adhesion between vessel and molded parts
Data Source
AI summary
Provided is a fuel system comprising a fuel vessel, molded parts for a fuel and/or a tube for a fuel in which bodies are constituted from at least one of a thermoplastic resin and a synthetic rubber, wherein a coating layer is formed on the surfaces in at least one side of the insides and the outsides of the fuel vessel body, the molded part bodies for a fuel and/or the tube body for a fuel or at least one of connected parts in these bodies; the above coating layer is formed by curing a polyurethane resin composition comprising an active hydrogen-containing compound (A) and an organic polyisocyanate compound (B); and the above coating layer has a gasoline permeability coefficient of 2 g·mm/m2·day or less at 23° C. and a relative humidity of 60% RH. The above coating layer is excellent in a permeation-preventing performance against an automobile fuel (gasoline barrier property), an adhesion property between fuel vessel body and molding parts or tube, a heat resistance and an impact resistance, a flexibility, a bending resistance, etc., then a fuel vessel, molded parts for a fuel and a tube for a fuel which have excellent performances are obtained.