Toner External Additives Preventing Aggregation via Silane Coupling
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Solution Overview
Problem
Hydrotalcite particles containing fluorine, when used with silica particles, tend to form aggregates due to strong adhesion, hindering the microcarrier effect and leading to deterioration in electrification properties and fluidity, especially during long-term use in varying environments.
Innovation Solution
A toner composition is developed with specific ratios of hydrotalcite and silica particles, where fluorine is intercalated within the hydrotalcite layers, and the silica particles are surface-treated to control their chemical structure and interaction, ensuring optimal electrification, developability, and fluidity through careful adjustment of content ratios and surface treatment agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrotalcite particles containing fluorine and silica particles are used together as external additives, then electrification property is improved, but the silica particles adhere to the surface of hydrotalcite particles to form aggregates, hindering the microcarrier effect
Solution Approach 1:
A silane coupling agent is introduced as an intermediary substance between the silica particles and hydrotalcite particles. The silane coupling agent chemically bonds to both surfaces, creating a protective interface that prevents direct adhesion between silica and hydrotalcite particles, thereby eliminating aggregation while preserving the electrification enhancement benefits of both additives
Solution Approach 2:
The surface chemical properties of silica particles are modified by controlling the silane treatment conditions, including the type of silane coupling agent, treatment temperature, and treatment time. These parameter changes create an optimized surface state that reduces electrostatic attraction between particles while maintaining the desired electrification properties of the toner
2Ease of operation
If silica particles are added to improve fluidity, then fluidity is enhanced, but aggregation with hydrotalcite particles occurs, deteriorating developability
Solution Approach 1:
The silane coupling agent serves as a mediator that allows silica particles to maintain their fluidity-enhancing function while preventing their harmful aggregation effect. By chemically modifying the silica surface, the agent enables particles to remain dispersed and mobile (improving fluidity) while simultaneously preventing adhesion to hydrotalcite particles (preserving developability)
3Reliability
If fluorine is added to hydrotalcite particles to enhance electrification property, then electrification is improved, but adhesion to silica particles increases, causing aggregation
Solution Approach 1:
The silane coupling agent acts as a force-dampening intermediary between the fluorine-containing hydrotalcite particles and silica particles. It chemically bonds to both surfaces, creating a buffer layer that reduces the strong electrostatic adhesion forces between the oppositely charged particles, thereby preventing aggregation while allowing both additives to function
Solution Approach 2:
A composite surface structure is created on the silica particles through silane treatment, forming a multi-layered interface that combines the properties of silica, silane coupling agent, and hydrotalcite. This composite structure reduces direct particle-to-particle contact and minimizes adhesion forces while maintaining the electrification benefits
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 toner achieves high electrification properties, developability, and fluidity consistently across different environments, preventing aggregation and maintaining performance over long-term use by controlling the content and surface treatment of hydrotalcite and silica particles.
Implementation Method 1
hydrotalcite particles containing fluorine... in order to impart a high electrification property
Implementation Method 2
the silica particles may adhere to the surface of the hydrotalcite particles containing fluorine to form aggregates
Data Source
AI summary
A toner comprising a toner particle and an external additive, wherein the external additive comprises a silica particle and a hydrotalcite particle containing fluorine which is present in cross sections of the hydrotalcite particle, wherein, when a content of the hydrotalcite particle containing the fluorine and a content of the silica particle to 100 parts by mass of the toner particle are defined as Wh and Ws respectively, Wh and Ws are in specific ranges, and a sum of areas of peaks which are present in a range of −140 to 100 ppm of a chemical shift of the silica particle obtained by a solid-state 29Si-NMR DD/MAS method is defined as S, the area of the peak of a D unit and Q unit are defined as D and Q respectively, the Wh, the Ws, S, the D, and the Q satisfy a specific relationship.