Core-Shell Polymer Clear Ink for Uniform Gloss Brightness

Solution Overview

Problem

Existing ink jet recording technologies face challenges in achieving uniform gloss brightness and clarity when using combinations of pigment inks with different pigment content, as previous solutions have issues with polymer particle stability, size, and cross-linked structures that affect ejection stability and film-forming ability.

Innovation Solution

A clear ink with a core-shell structured polymer fine particle is developed, where the core polymer includes a unit derived from a monomer with a chain structure saturated alkyl group, providing improved van der Waals forces for surface retention and dispersion stability, and the shell polymer is optimized for acid value and molecular weight to enhance ejection and film formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If cross-linked core-shell structured polymer particles are used to improve surface retention and film formation, then gloss brightness and uniformity are improved, but ejection stability deteriorates

Engineering Contradiction:

Improvegloss brightness uniformityVSAvoidejection stability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The polymer particle is divided into two distinct functional regions: a cross-linked core providing structural stability and surface retention, and a non-cross-linked shell providing flexibility and ejection stability. This segmentation allows each region to independently fulfill its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different parts of the polymer particle have different structural properties: the core has cross-linked structure for rigidity and surface adhesion, while the shell has non-cross-linked structure for flexibility and ejection performance. This local differentiation resolves the contradiction between surface retention and ejection stability.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If polymer particles with higher molecular weight are used to improve film-forming ability, then gloss clarity is improved, but ejection stability deteriorates

Engineering Contradiction:

Improvegloss clarityVSAvoidejection stability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The polymer particle is divided into two distinct functional regions: a cross-linked core providing structural stability and surface retention, and a non-cross-linked shell providing flexibility and ejection stability. This segmentation allows each region to independently fulfill its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different parts of the polymer particle have different structural properties: the core has cross-linked structure for rigidity and surface adhesion, while the shell has non-cross-linked structure for flexibility and ejection performance. This local differentiation resolves the contradiction between surface retention and ejection stability.

Inventive Principle:

Principle #3Local quality

3Quantity of substance

If pigment ink with high pigment content is used to achieve deep color, then color saturation is improved, but gloss brightness uniformity deteriorates

Engineering Contradiction:

Improvepigment contentVSAvoidgloss brightness uniformity

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The clear ink containing core-shell polymer particles acts as an intermediary layer applied over the pigment ink. This intermediary polymer layer fills in the gloss variations caused by high pigment content, providing a unifying surface that restores gloss brightness uniformity without reducing color saturation.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 clear ink achieves high ejection stability, uniform gloss brightness, and excellent gloss clarity, regardless of the type of pigment ink used, by ensuring the polymer particles remain on the surface and form a uniform film, improving image sharpness and durability.

Implementation Method 1

the core polymer includes a unit derived from a monomer with a chain structure saturated alkyl group, providing improved van der Waals forces for surface retention

Methodology Applied

Scientific Effectvan der Waals force: Van der Waals Force

Data Source

PatentEP2270109B1Clear ink, ink jet recording method, ink set, ink cartridge, recording unit and ink jet recording apparatus

Publication Date: 2014.10.08 CANON KK

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AI summary

Provided is an ink jet clear ink containing a polymer fine particle. The polymer fine particle has a core-shell structure obtained by polymerizing an α,β-ethylenically unsaturated hydrophobic monomer (b) as a core polymer in the presence of a shell polymer that is a copolymer having at least a unit derived from an α,β-ethylenically unsaturated hydrophobic monomer (a) and a unit derived from a monomer selected from an α,β-ethylenically unsaturated acid monomer and a salt thereof. The α,β-ethylenically unsaturated hydrophobic monomer (b) includes at least a monomer containing a chain structure saturated alkyl group.