TFE-PPVE Copolymer Composition for Heat-Resistant Low-Permeability Moldings

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Solution Overview

Problem

Conventional fluororesin-based eating utensils and sealed containers face issues with abrasion resistance, rigidity on heating, creep resistance, heat distortion resistance after warm water immersion, and nitrogen low permeability, leading to damage during repeated use and storage of food items.

Innovation Solution

A copolymer containing tetrafluoroethylene (TFE) and perfluoro(propyl vinyl ether) (PPVE) units, with specific content ranges and melt flow rates, is used to enhance the properties of formed articles, allowing for improved abrasion resistance, nitrogen low permeability, creep resistance, and heat distortion resistance, while minimizing fluorine ion dissolution in chemical solutions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional fluororesin is used for eating utensils and sealed containers, then the material provides basic chemical resistance, but the abrasion resistance, rigidity on heating, creep resistance, and heat distortion resistance after warm water immersion are insufficient

Engineering Contradiction:
Improveabrasion resistanceVSAvoidrigidity on heating
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies parameter changes by precisely controlling the PPVE unit content (4.9-5.7% by mass), melt flow rate (45.0-55.0 g/10 min at 372°C), and functional group count (50 or less per 10^6 main-chain carbon atoms) to achieve optimal balance between abrasion resistance and heat resistance. This quantitative control of compositional parameters resolves the contradiction between softness needed for abrasion resistance and rigidity needed for heat resistance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite material principles by creating a copolymer system combining TFE and PPVE units with specific compositional ratios. The copolymer structure integrates the chemical resistance of PTFE with the enhanced mechanical properties and heat resistance provided by controlled PPVE incorporation, achieving superior overall performance compared to conventional homopolymers.

Inventive Principle:
Principle #40Composite materials

2Reliability

If conventional fluororesin is used for sealed containers, then the material provides basic nitrogen barrier properties, but the nitrogen low permeability is insufficient for long-term food storage

Engineering Contradiction:
Improvenitrogen low permeabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent achieves improved nitrogen low permeability by changing the compositional parameters of the copolymer, specifically controlling the PPVE unit content within 4.9-5.7% by mass. This precise parameter control creates a molecular structure with optimized free volume and chain packing, resulting in superior nitrogen barrier properties without requiring complex multi-layer structures or additional manufacturing steps.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If thin coating layer is formed on small-diameter core wire by extrusion forming, then the coating productivity increases, but the coating uniformity and defect-free quality become difficult to achieve

Engineering Contradiction:
Improvecoating formation efficiencyVSAvoidcoating thickness uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent resolves the contradiction between productivity and coating quality by changing the rheological parameters of the copolymer. The controlled melt flow rate (45.0-55.0 g/10 min at 372°C) and molecular weight distribution enable the material to flow uniformly during extrusion coating while maintaining consistent thickness. The low functional group count (≤50 per 10^6 main-chain carbon atoms) reduces viscosity variations, ensuring uniform coating formation on small-diameter core wires with high productivity and defect-free quality.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If fluororesin is used in chemical solutions such as hydrogen peroxide solution, then the material provides chemical resistance, but fluorine ions dissolve out over time

Engineering Contradiction:
Improvechemical resistanceVSAvoidfluorine ion dissolution
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent addresses fluorine ion dissolution by changing the chemical compositional parameters of the copolymer. The specific PPVE unit content (4.9-5.7% by mass) and low functional group count (≤50 per 10^6 main-chain carbon atoms) create a chemically stable structure with minimized reactive sites. This compositional optimization maintains excellent chemical resistance to hydrogen peroxide solutions while significantly reducing fluorine ion dissolution compared to conventional fluororesins with higher functional group content.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20230406975A1Copolymer, molded body, injection molded body, and coated electrical wire
Publication Date: 2023.12.21 DAIKIN INDUSTRIES LTD

AI summary

There is provided a copolymer containing tetrafluoroethylene unit and perfluoro(propyl vinyl ether) unit, wherein the copolymer has a content of perfluoro(propyl vinyl ether) unit of 4.9 to 5.7% by mass with respect to the whole of the monomer units, a melt flow rate at 372° C. of 45.0 to 55.0 g/10 min, and the number of functional groups of 50 or less per 106 main-chain carbon atoms.