Fluorine-Attached PTFE Particles for Stable Dispersion
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Solution Overview
Problem
Polytetrafluoroethylene (PTFE) particles experience decreased dispersibility and aggregation when the state of the mixed component changes, such as during evaporation of a dispersion medium or melting of a powder, due to the presence of perfluorooctanoic acid (PFOA), leading to a low dispersion state in layered materials used in electrophotographic photoreceptors.
Innovation Solution
A dispersant attached PTFE particle with a fluorine atom, where the content of perfluorooctanoic acid is limited to 0-25 ppb, utilizing a polymer dispersant obtained by homopolymerization or copolymerization of polymerizable compounds with fluorinated alkyl groups, maintaining high dispersion state even when the component state changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If perfluorooctanoic acid (PFOA) is used as a dispersant for polytetrafluoroethylene particles, then dispersibility is improved, but aggregation occurs when the state of the mixed component changes (evaporation or melting)
Solution Approach 1:
The invention changes the chemical parameter of the dispersant from PFOA to a fluorine-containing polymer dispersant with specific molecular structure (containing CF3 group and repeating units with specific fluorinated alkyl groups). This parameter change in the dispersant chemistry enables the dispersion state to be maintained when the state of mixed components changes, resolving the contradiction between initial dispersibility and long-term stability.
2Quantity of substance
If a fluorine-containing dispersant is used with polytetrafluoroethylene particles, then dispersibility is improved, but dispersibility decreases when the state of the component mixed changes
Solution Approach 1:
The invention uses a composite dispersant system consisting of a fluorine-containing polymer dispersant with specific structural units (CF3 group and fluorinated alkyl repeating units). This composite molecular structure combines the dispersing capability with the stability to maintain dispersion when component state changes, resolving the contradiction between dispersibility and reliability.
3Quantity of substance
If PFOA content exceeds 25 ppb in PTFE particles, then dispersibility is improved, but aggregation occurs leading to low dispersion state in layered materials
Solution Approach 1:
The invention changes the dispersant parameter from PFOA (carboxylic acid type) to a fluorine-containing polymer dispersant (polymer type with specific fluorinated alkyl groups). This parameter change eliminates aggregation issues and ensures uniform dispersion state in layered materials, resolving the contradiction between dispersibility and manufacturing precision.
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 dispersant attached PTFE particles maintain high dispersibility and prevent aggregation, enhancing the maintainability of the dispersion state and surface properties like lubricity and hydrophobicity in electrophotographic photoreceptors, reducing image defects and improving the performance of electrophotographic photoreceptors and image forming apparatuses.
Implementation Method 1
a dispersant having a fluorine atom is attached on its surface
Data Source
Figure 1~2
Figure 3
AI summary
A dispersant attached polytetrafluoroethylene particle on whose surface a dispersant having a fluorine atom is attached has a content of perfluorooctanoic acid of from 0 ppb to 25 ppb with respect to the polytetrafluoroethylene particle, and a composition contains a polytetrafluoroethylene particle and a dispersant having a fluorine atom in which a content of perfluorooctanoic acid is from 0 ppb to 25 ppb with respect to the polytetrafluoroethylene particle.