Purified PTFE Dispersion and Powder With Reduced Fluorinated Impurities
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Solution Overview
Problem
The production of polytetrafluoroethylene using hydrocarbon surfactants results in the generation of specific fluorine-containing compounds that need to be removed or reduced.
Innovation Solution
A method involving ion-exchange, concentration, heating, or contact with a fluorine radical source is used to remove or reduce compounds represented by specific formulas from polytetrafluoroethylene dispersions and powders produced with hydrocarbon surfactants, achieving a composition with reduced fluorine content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polytetrafluoroethylene is produced using a hydrocarbon surfactant, then the production process is simple and cost-effective, but fluorine-containing compounds (compounds of formula (1) or (2)) are generated as impurities
Solution Approach 1:
The patent applies extraction by adding a specific organic solvent to the aqueous dispersion to selectively extract and remove fluorine-containing compounds (compounds of formula (1) or (2)) from the polytetrafluoroethylene product, separating the harmful impurities from the desired product
Solution Approach 2:
The patent changes the chemical composition parameter by introducing a specific organic solvent (with particular molecular structure characteristics) to alter the system's properties, enabling selective removal of fluorine-containing compounds through solubility differences
2Manufacturing precision
If ion-exchange and concentration methods are used to remove fluorine-containing compounds from aqueous dispersion, then the purity of polytetrafluoroethylene is improved, but the process complexity and time increase
Solution Approach 1:
The patent uses extraction with organic solvent as a simpler alternative to complex ion-exchange processes, removing fluorine-containing compounds through liquid-liquid extraction which is less complex than ion-exchange equipment and procedures
Solution Approach 2:
The patent employs a simple, one-step extraction process using readily available organic solvents rather than complex, expensive ion-exchange systems requiring specialized resins and equipment, achieving purification with simpler, more economical means
3Object-generated harmful factors
If heating at 160°C or more is applied to remove fluorine-containing compounds from polytetrafluoroethylene powder, then the compound removal is effective, but energy consumption increases
Solution Approach 1:
The patent replaces thermal energy input (heating at 160°C or more) with chemical extraction using organic solvents, substituting a thermal process with a chemical separation process that operates at lower temperatures and consumes less energy
Solution Approach 2:
The patent changes the removal mechanism from thermal decomposition/extraction to solvent-based extraction, altering the fundamental parameter from temperature-dependent removal to solubility-dependent removal, thereby reducing energy requirements
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 method effectively removes or reduces the specified fluorine-containing compounds, resulting in purified polytetrafluoroethylene dispersions, powders, and molded bodies with minimal residual fluorine content.
Implementation Method 1
The removal or reduction of a compound represented by Formula (1) or (2) above preferably comprises ion-exchanging and/or concentrating the aqueous dispersion of polytetrafluoroethylene.
Implementation Method 2
The removal or reduction of a compound represented by Formula (1) or (2) above preferably comprises heating the polytetrafluoroethylene powder obtained using a hydrocarbon surfactant at a temperature of 160° C. or more.
Implementation Method 3
removing or reducing a compound represented by Formula (1) or (2) below by bringing a fluorine radical source into contact with polytetrafluoroethylene obtained using a hydrocarbon surfactant at a temperature over 100° C.
Data Source
AI summary
A composition containing polytetrafluoroethylene and substantially free from a compound represented by Formula (3):(H—(CF2)8—SO3)qM2 wherein M2 is H, a metal atom, NR54 (where R5s may be the same as or different from each other and are each H or an organic group having 1 to 10 carbon atoms), an imidazolium optionally having a substituent, a pyridinium optionally having a substituent, or a phosphonium optionally having a substituent, and q is 1 or 2. Also disclosed is a molded boy including the composition.