Core-Shell Polyester Silane Toner Additives

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Solution Overview

Problem

In electrophotographic processes, toner additives face challenges in maintaining flowability, preventing embedding, and ensuring tribocharge stability while also facilitating low-temperature fusing and high storage stability, without interfering with the printing process.

Innovation Solution

The development of core-shell composite particles comprising a polyester core and a polymer or copolymer shell of ethylenically unsaturated silane compounds, produced through a process involving radical polymerization and hydrolysis, which are used as toner additives to enhance flowability and fusing properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If hard additive particles are used to maintain flowability and prevent agglomeration, then spacing and flowability are improved, but embedding in soft toner particles increases and tribocharge characteristics deteriorate

Engineering Contradiction:

ImproveflowabilityVSAvoidtribocharge characteristics

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent applies parameter changes by carefully controlling the size range of silica particles (0.1-10 micrometers) and their surface properties to achieve optimal flowability while preventing embedding. The specific particle size parameters are optimized to balance spacing functionality with resistance to embedding in soft toner particles.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining silica particles with specific surface treatments and coatings that provide both the hardness needed for flowability maintenance and the surface properties that prevent embedding and preserve tribocharge characteristics.

Inventive Principle:

Principle #40Composite materials

2Strength

If larger additive particle sizes are used to reduce embedding, then embedding is reduced, but drop-off from toner particles increases

Engineering Contradiction:

Improveresistance to embeddingVSAvoidadditive drop-off

Core Design Contradiction:

StrengthVSLoss of substance

Solution Approach 1:

The patent applies parameter changes by optimizing the particle size distribution of additives to a specific range (0.1-10 micrometers) that balances resistance to embedding with sufficient adhesion to prevent drop-off. This precise parameter control resolves the contradiction between these two opposing requirements.

Inventive Principle:

Principle #35Parameter changes

3Temperature

If softer polymers are used to reduce fusing temperature and energy consumption, then fusing temperature is reduced, but toner particle cohesion decreases and agglomeration increases

Engineering Contradiction:

Improvefusing temperatureVSAvoidparticle cohesion

Core Design Contradiction:

TemperatureVSStability of the object's composition

Solution Approach 1:

The patent uses composite materials by combining softer polymer matrices with carefully selected additive particles that provide both low-temperature fusing capability and sufficient particle cohesion. The composite structure allows the soft polymer to reduce fusing temperature while the additive particles maintain structural integrity.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by creating regions of different properties within the toner particle structure, where the softer polymer provides low-temperature fusing in specific areas while the additive particles and harder polymer regions maintain overall particle cohesion and prevent agglomeration.

Inventive Principle:

Principle #3Local quality

4Speed

If toner additives are used to improve flowability and prevent embedding, then spacing is improved, but interference with the printing and fusing process increases

Engineering Contradiction:

ImproveflowabilityVSAvoidprinting process interference

Core Design Contradiction:

SpeedVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by optimizing the concentration, size, and surface properties of additives to ensure they provide flowability benefits while their physical and chemical parameters are tuned to be compatible with the printing and fusing processes, minimizing interference.

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

These particles improve toner flow and fusion at lower temperatures, maintain structural integrity, and ensure stability during storage and printing, thereby enhancing print quality and durability.

Implementation Method 1

radically polymerizing the ethylenically unsaturated silane compound to provide a dispersion of core-shell particles

Methodology Applied

Scientific EffectRadical polymerization: Photopolymerisation

Implementation Method 2

cross-linking the polymerized ethylenically unsaturated silane compound by hydrolyzing and condensing at least a portion of the alkoxysilane groups

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Implementation Method 3

cross-linking the polymerized ethylenically unsaturated silane compound by hydrolyzing and condensing at least a portion of the alkoxysilane groups

Methodology Applied

Scientific EffectCondensation: Condensation

Data Source

PatentUS11773255B2Nanocomposites containing crystalline polyester and organosilica

Publication Date: 2023.10.03 CABOT CORP

AI summary

The invention provides a process for preparing core-shell composite particles comprising a polyester, polymerized ethylenically unsaturated silane compounds, and optionally a hydrophobic surface treatment. The invention further provides a composite particle comprising a polyester and a radically polymerized ethylenically unsaturated silane compound.