Fluoropolymer Composition for Methane Barrier and High-Temperature Rigidity

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Solution Overview

Problem

Conventional fluorine-containing copolymers, such as terpolymers containing tetrafluoroethylene, hexafluoropropylene, and perfluoro(ethyl vinyl ether), lack superior high-temperature abrasion resistance, high-temperature rigidity, and durability, particularly in applications like methane gas supply tubes and films, which require excellent methane low permeability, tensile creep resistance, and durability under high-temperature conditions.

Innovation Solution

A fluorine-containing copolymer comprising tetrafluoroethylene, hexafluoropropylene, and perfluoro(propyl vinyl ether) units, with specific content ranges of 9.5 to 12.2% hexafluoropropylene, 0.5 to 1.4% perfluoro(propyl vinyl ether), and a melt flow rate of 0.8 to 4.0 g/10 min, optimized to enhance extrusion formability and achieve excellent 50° C. abrasion resistance, methane low permeability, 100° C. high-temperature rigidity, 130° C. tensile creep resistance, and durability to repeated loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional fluorine-containing copolymers (terpolymers containing tetrafluoroethylene, hexafluoropropylene, and perfluoro(ethyl vinyl ether)) are used, then basic copolymerization is achieved, but superior high-temperature abrasion resistance, high-temperature rigidity, and durability are not obtained

Engineering Contradiction:
Improvehigh-temperature abrasion resistanceVSAvoidcopolymer composition control
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by precisely controlling the composition ratios of monomer units (tetrafluoroethylene: 78.0-90.0 mass%, hexafluoropropylene: 9.5-12.2 mass%, perfluoro(propyl vinyl ether)l: 0.5-1.4 mass%) and adjusting the melt flow rate (0.8-4.0 g/10min) to achieve optimal high-temperature abrasion resistance and rigidity while maintaining manufacturability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite fluorine-containing copolymer structure by combining three different monomer units with specific functional characteristics: tetrafluoroethylene provides base polymer strength, hexafluoropropylene enhances chemical resistance and mechanical properties, and perfluoro(propyl vinyl ether) improves processability and surface properties, achieving superior high-temperature performance through compositional synergy

Inventive Principle:
Principle #40Composite materials

2Reliability

If conventional fluorine-containing copolymers are used, then basic film formation is achieved, but excellent methane low permeability, tensile creep resistance, and durability under high-temperature conditions are not obtained

Engineering Contradiction:
Improvemethane low permeabilityVSAvoidfilm thickness uniformity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent achieves excellent methane low permeability and film uniformity by optimizing the melt flow rate parameter (0.8-4.0 g/10min) and controlling the composition of perfluoro(propyl vinyl ether) unit (0.5-1.4 mass%), which improves processability and enables precise film formation with consistent thickness while maintaining low gas permeability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The composite copolymer structure combines tetrafluoroethylene (providing low gas permeability), hexafluoropropylene (enhancing mechanical strength for creep resistance), and perfluoro(propyl vinyl ether) (improving processability for uniform film formation), achieving multiple performance requirements simultaneously through compositional design

Inventive Principle:
Principle #40Composite materials

3Strength

If hexafluoropropylene content is increased to improve mechanical properties, then abrasion resistance and rigidity improve, but extrusion formability deteriorates

Engineering Contradiction:
Improveabrasion resistanceVSAvoidextrusion formability
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent resolves this contradiction by precisely controlling the hexafluoropropylene content (9.5-12.2 mass%) to maximize mechanical properties while simultaneously adjusting the perfluoro(propyl vinyl ether) content (0.5-1.4 mass%) and melt flow rate (0.8-4.0 g/10min) to maintain excellent extrusion formability, achieving a balanced optimization of competing requirements

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If perfluoro(propyl vinyl ether) content is increased to improve processability, then extrusion formability improves, but high-temperature rigidity deteriorates

Engineering Contradiction:
Improveextrusion formabilityVSAvoidhigh-temperature rigidity
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The patent optimizes the perfluoro(propyl vinyl ether) content (0.5-1.4 mass%) within a narrow range to achieve sufficient extrusion formability while preventing excessive softening at high temperatures, and compensates by precisely controlling the hexafluoropropylene content (9.5-12.2 mass%) to maintain high-temperature rigidity through compositional balance

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20230399436A1Fluorine-containing copolymer
Publication Date: 2023.12.14 DAIKIN INDUSTRIES LTD

AI summary

There is provided a fluorine-containing copolymer containing tetrafluoroethylene unit, hexafluoropropylene unit, and a perfluoro(propyl vinyl ether) unit, wherein the copolymer has a content of hexafluoropropylene unit of 9.5 to 12.2% by mass with respect to the whole of the monomer units, a content of perfluoro(propyl vinyl ether) unit of 0.5 to 1.4% by mass with respect to the whole of the monomer units, a melt flow rate at 372° C. of 0.8 to 4.0 g/10 min, and a number of —CF2H of more than 50 per 106 main-chain carbon atoms.