Polyamide Gas Tank Liner with Nucleating Agent

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Solution Overview

Problem

Existing gas storage tank liners suffer from insufficient barrier properties, leading to fiber degradation and permeation issues, which result in material inefficiencies and potential buckling when pressure is low.

Innovation Solution

A polymer composition for the liner comprising polyamide A, a nucleating agent at least 0.001 weight percent, and an impact modifier at least 1 weight percent, which enhances barrier properties, reduces fiber degradation, and minimizes buckling, while maintaining stiffness and blow molding properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional polyethylene liner is used, then the liner provides basic containment, but the barrier properties are insufficient leading to gas permeation and fiber degradation

Engineering Contradiction:
Improvebarrier propertiesVSAvoidgas permeation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the liner material by incorporating polyamide resin (6-16 weight percent), copolyamide resin (16-60 weight percent), and impact-resistant material (20-50 weight percent) to achieve superior barrier properties against gas permeation while maintaining structural integrity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite material system combining polyamide resin, copolyamide resin, and impact-resistant material in specific proportions to create a liner that simultaneously provides excellent barrier properties, mechanical strength, and impact resistance, resolving the contradiction between containment and permeation prevention

Inventive Principle:
Principle #40Composite materials

2Reliability

If the liner thickness is increased to improve barrier properties, then permeation resistance improves, but material usage increases and processing becomes more difficult

Engineering Contradiction:
Improvebarrier propertiesVSAvoidprocessing difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent optimizes the compositional parameters of the polymer mixture to achieve high barrier properties in a thin liner configuration (0.5-2.0 mm thickness), where the specific resin combination provides superior gas permeation resistance per unit thickness compared to conventional materials, thus reducing overall material usage while maintaining effectiveness

Inventive Principle:
Principle #35Parameter changes

3Reliability

If a polyamide-based liner with impact modifier is used, then barrier properties improve, but the stiffness of the liner may be reduced

Engineering Contradiction:
Improvebarrier propertiesVSAvoidstiffness
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent creates a balanced composite material system where polyamide resin provides stiffness and structural integrity, copolyamide resin enhances barrier properties, and impact-resistant material (added in 20-50 weight percent) improves toughness without compromising overall stiffness, thus resolving the contradiction between barrier performance and mechanical strength

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent assigns different functional properties to different components: polyamide resin for stiffness, copolyamide for barrier enhancement, and impact-resistant material for toughness, allowing each component to optimize its local function while contributing to overall liner performance

Inventive Principle:
Principle #3Local quality

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 improved liner exhibits reduced permeability to gases like helium and nitrogen, allows for thinner or fewer layers, and better protects vacuum spaces from permeation, resulting in material savings and improved structural integrity.

Implementation Method 1

a nucleating agent in an amount of at least 0.001 weight percent with respect to the total amount of the polymer composition

Methodology Applied
Scientific EffectNucleation: Nucleation

Implementation Method 2

Gas which permeates through the liner may brittle the fibers

Methodology Applied
Scientific EffectPermeation: Permeation

Data Source

PatentUS9470366B2Liner for gas storage tank
Publication Date: 2016.10.18 ENVALIOR BV

AI summary

This invention relates to a liner for a gas storage tank containing a polymer composition comprising: i. a polyamide A, and ii. a nucleating agent in an amount of at least 0.001 weight percent with respect to the total amount of the polymer composition, and iii. an impact modifier in an amount of at least 1 weight percent with respect to the total amount of the polymer composition. The invention also relates to a gas storage tank comprising a structural fiber composite comprising continuous carbon or glass fibers, as well as a method for preparing a liner by blow molding.