Multilayer Fuel Container with EVOH and Adhesive Resin

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Solution Overview

Problem

Fuel containers made of plastic, particularly those with an EVOH layer, face issues with foreign matter contamination that reduce impact resistance and fuel barrier properties over time, leading to instability in production.

Innovation Solution

A multilayer fuel container structure comprising an EVOH layer, a maleic anhydride-modified polyolefin adhesive resin layer, and a high-density polyethylene layer, with specific composition and thickness ratios to enhance fuel barrier properties and impact resistance, while minimizing foreign matter generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a multilayer structure with EVOH layer is used to improve fuel barrier properties, then fuel barrier properties are improved, but foreign matter derived from EVOH occurs in recovered material layer, reducing impact resistance and fuel barrier properties over time

Engineering Contradiction:
Improvefuel barrier propertiesVSAvoidproduction stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The invention divides the fuel container into multiple layers with distinct functions: an inner layer made of recovered material containing EVOH for fuel barrier properties, and an outer layer made of virgin high-density polyethylene for impact resistance and structural integrity. This segmentation allows each layer to perform its specific function optimally while preventing foreign matter from compromising the entire structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the fuel container are assigned different material qualities: the inner layer uses recovered material with EVOH content of 5-50 mass% to provide fuel barrier properties, while the outer layer uses virgin high-density polyethylene to provide impact resistance. This local differentiation of material properties resolves the contradiction between fuel barrier performance and production stability.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If recovered material layer is used to reduce waste and production cost, then environmental protection and cost reduction are achieved, but foreign matter derived from EVOH reduces impact resistance and fuel barrier properties

Engineering Contradiction:
Improveproduction costVSAvoidimpact resistance
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The fuel container is segmented into an inner layer using recovered material (containing EVOH and adhesive resin) and an outer layer using virgin high-density polyethylene. This segmentation allows the use of cost-effective recovered material while maintaining impact resistance through the virgin material outer layer.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention creates a composite structure where the inner layer is a mixture of recovered material components (EVOH, adhesive resin, and other polymers) and the outer layer is virgin high-density polyethylene. This composite approach combines the fuel barrier properties of EVOH with the impact resistance of virgin polyethylene, achieving both cost reduction and maintained strength.

Inventive Principle:
Principle #40Composite materials

3Reliability

If EVOH content in recovered material is increased to improve fuel barrier properties, then fuel barrier properties are improved, but foreign matter occurrence increases, reducing production stability

Engineering Contradiction:
Improvefuel barrier propertiesVSAvoidproduction stability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The EVOH-containing recovered material is localized to the inner layer where it provides fuel barrier properties, while the outer layer uses virgin material free from foreign matter. This spatial localization allows high EVOH content (5-50 mass%) in the inner layer without compromising production stability, as the foreign matter remains confined to the inner layer and does not affect the overall structural integrity.

Inventive Principle:
Principle #3Local quality

Data Source

PatentUS11279117B2Fuel container
Publication Date: 2022.03.22 KURARAY CO LTD

AI summary

Provided is a fuel container composed of a multilayer structure containing: an ethylene-vinyl alcohol copolymer (A) layer; an adhesive resin (B) layer; a high-density polyethylene (C) layer; and a resin composition (D) layer, wherein the ethylene-vinyl alcohol copolymer (A) contains 15 to 44 mol % of ethylene, the adhesive resin (B) is a maleic anhydride-modified polyolefin having an acid value of 0.1 to 10 mgKOH/g and containing 1 to 8.5 μmol/g of magnesium element, calcium element, zinc element, or a combination thereof, the resin composition (D) contains the ethylene-vinyl alcohol copolymer (A), the adhesive resin (B), and the high-density polyethylene (C), the thickness of the (A) layer, the (B) layer, and the (C) layer satisfies specific conditions, and the ethylene-vinyl alcohol copolymer (A), the adhesive resin (B), and the high-density polyethylene (C) satisfies specific conditions. The fuel container is excellent in fuel barrier properties and impact resistance and enables stable production.