Toner Particle Size Control via Carboxylic Acid in Emulsion Polymerization

Solution Overview

Problem

Existing toner production methods face challenges due to variability in starting materials, leading to inconsistent particle sizes and undesirable physical characteristics, making it difficult to produce toners suitable for electrostatographic apparatuses.

Innovation Solution

The process involves using a carboxylic acid, such as acrylic acid, in combination with a stabilizer like beta carboxyethyl acrylate to control the particle size of latex resins during emulsion polymerization, ensuring consistent and suitable toner particle sizes through the formation of seed particles and subsequent latex polymerization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional toner production methods are used, then existing processing equipment can be utilized, but particle size variability increases due to material impurities

Engineering Contradiction:

Improveparticle size consistencyVSAvoidprocess sensitivity to material variability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-forming seed particles with controlled size and composition before the main polymerization step. These seed particles serve as templates that dictate the final toner particle size, making the process less sensitive to variations in subsequent material additions. The seed particles are formed first, then monomers are polymerized around them in a controlled manner.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent utilizes parameter changes by carefully controlling the molecular weight and composition of the polymer used to form seed particles. By adjusting parameters such as polymer chain length, functional group content, and crosslinking density, the process achieves consistent toner particle sizes despite variations in starting materials. The molecular weight of the seed-forming polymer is specifically optimized to control final particle dimensions.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If emulsion aggregation methods are used, then toner particles can be formed by aggregating colorant with latex polymer, but particle size control becomes sensitive to material variability

Engineering Contradiction:

Improveprocess simplicityVSAvoidparticle size control

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-forming seed particles with controlled size and composition before the main polymerization step. These seed particles serve as templates that dictate the final toner particle size, making the process less sensitive to variations in subsequent material additions. The seed particles are formed first, then monomers are polymerized around them in a controlled manner.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent utilizes parameter changes by carefully controlling the molecular weight and composition of the polymer used to form seed particles. By adjusting parameters such as polymer chain length, functional group content, and crosslinking density, the process achieves consistent toner particle sizes despite variations in starting materials. The molecular weight of the seed-forming polymer is specifically optimized to control final particle dimensions.

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

This approach effectively minimizes the impact of material variability, producing toners with desired particle sizes ranging from 80 nm to 800 nm, suitable for use in electrostatographic apparatuses, and enhances the stability and quality of the toner production process.

Implementation Method 1

processes including contacting a latex with a carboxylic acid and a stabilizer... wherein the carboxylic acid is present in an amount sufficient to reduce the particle size of the resulting latex resin

Methodology Applied

Scientific EffectEmulsion polymerization:

Data Source

PatentUS8455171B2Toner compositions

Publication Date: 2013.06.04 GENESEE VALLEY INNOVATIONS LLC

AI summary

The present disclosure provides processes for reducing the particle size of latex resins and toners produced with such resins. In embodiments, a carboxylic acid may be added to materials utilized to produce a latex and reduce the particle size of the resulting latex particles and toner particles. In accordance with the present disclosure, one may be able to utilize materials for the production of latex resins and toners which may otherwise produce particles that are too large in the absence of the carboxylic acid.