Modified PTFE Dispersion for Low Viscosity at High Temperature

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Solution Overview

Problem

Existing polytetrafluoroethylene (PTFE) aqueous dispersions face issues with high viscosity at elevated temperatures, which complicates applications requiring high-temperature processing such as impregnation of fibrous substrates, and lack sufficient mechanical stability and film formability.

Innovation Solution

A modified PTFE aqueous dispersion is developed with a nonionic surfactant, containing 50-70% PTFE by mass, minimal fluorine-containing surfactants, and controlled amounts of polymerized modifying monomer units, achieving a viscosity of 80 mPa·s or lower at 55°C and a viscosity-temperature ratio of 4.00 or lower, enhancing stability and film formability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional PTFE aqueous dispersion is used, then the dispersion can be stabilized with fluorine-containing surfactants, but the viscosity becomes excessively high at elevated temperatures

Engineering Contradiction:

ImprovestabilityVSAvoidviscosity at elevated temperature

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent changes the chemical composition parameters by replacing fluorine-containing surfactants with fluorine-free surfactants and incorporating specific polymer modifiers (0.01-5.0 mass%) that alter the viscosity-temperature relationship. This parameter change enables the dispersion to maintain stability while achieving viscosity of 80 mPa·s or lower at 55°C, resolving the contradiction between stability and high-temperature viscosity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite aqueous dispersion system combining PTFE particles with fluorine-free surfactants and polymer modifiers. This composite formulation leverages the synergistic effects of the components to achieve both stability and low viscosity at elevated temperatures, overcoming the limitations of conventional single-component surfactant systems.

Inventive Principle:

Principle #40Composite materials

2Reliability

If fluorine-containing surfactants are used to stabilize PTFE aqueous dispersion, then the dispersion is stable, but the viscosity-temperature ratio becomes excessively high

Engineering Contradiction:

Improvedispersion stabilityVSAvoidviscosity-temperature ratio

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent fundamentally changes the surfactant parameter from fluorine-containing to fluorine-free compounds, and introduces polymer modifiers at controlled concentrations. This parameter transformation reduces the viscosity-temperature ratio to 4.00 or lower while maintaining dispersion stability, enabling the formulation to adapt to high-temperature processing requirements.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If high PTFE solid concentration (50-70% by mass) is achieved, then the coating efficiency is improved, but the viscosity at elevated temperatures becomes excessively high

Engineering Contradiction:

Improvecoating efficiencyVSAvoidviscosity at 55°C

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The patent modifies the physical parameters of the dispersion by introducing polymer modifiers (0.01-5.0 mass%) that change the rheological properties. This enables the high solid concentration formulation (50-70% PTFE) to maintain viscosity of 80 mPa·s or lower at 55°C, achieving both high coating efficiency and processability at elevated temperatures.

Inventive Principle:

Principle #35Parameter changes

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 modified PTFE dispersion exhibits low viscosity at high temperatures, ensuring stable impregnation and uniform coating with excellent mechanical stability and film formability, suitable for high-temperature applications.

Implementation Method 1

Adding a nonionic surfactant as a dispersant to the aqueous dispersion is a known technique to stabilize the aqueous dispersion

Methodology Applied

Scientific EffectSurfactant: Surfactant

Implementation Method 2

Polytetrafluoroethylene (hereinafter, referred to as 'PTFE') is commonly produced by emulsion polymerization of tetrafluoroethylene (hereinafter, referred to as 'TFE') in an aqueous medium using a surfactant

Methodology Applied

Scientific EffectEmulsion polymerization: Emulsion

Data Source

PatentUS12565580B2Aqueous modified polytetrafluoroethylene dispersion

Publication Date: 2026.03.03 DAIKIN INDUSTRIES LTD

AI summary

A modified polytetrafluoroethylene aqueous dispersion having low viscosity at high temperature. The modified polytetrafluoroethylene aqueous dispersion contains a modified polytetrafluoroethylene and a nonionic surfactant, has a modified polytetrafluoroethylene solid concentration of 50 to 70% by mass, is substantially free from a fluorine-containing surfactant, and has a viscosity at 55° C. of 80 mPa·s or lower, and the modified polytetrafluoroethylene contains 0.050% by mass or more and 1.00% by mass or less of a polymerized unit based on a modifying monomer.