Core-shell resin particles for aqueous ink fixability
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Solution Overview
Problem
Ink jet recording technologies face challenges in achieving high fixability and abrasion resistance due to limitations in the composition of resin particles used in existing inks, particularly with core-shell structured resin particles that fail to adequately entangle and form stable films on recording media.
Innovation Solution
An aqueous ink containing resin particles with a specific core-shell structure, where the second resin layer has a tetrahydrofuran-insoluble fraction of 10% or more, includes a unit derived from an aromatic-group-containing ethylenically unsaturated monomer and an ionic-group-containing ethylenically unsaturated monomer, and the first resin layer has a limited aromatic-group content to facilitate entanglement and film formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resin particles with core-shell structure are used to improve fixability and abrasion resistance, then image stability improves, but the resin particles fail to entangle and form stable films adequately
Solution Approach 1:
The resin particle is designed with a core-shell structure where the core contains aromatic-group-containing monomer units for strong adhesion to recording media, while the shell contains ionic-group-containing monomer units for rapid entanglement and film formation. This local differentiation of functional groups resolves the contradiction by assigning specific roles to different regions of the same particle.
Solution Approach 2:
The invention uses composite resin particles combining two types of monomer units (aromatic-group-containing and ionic-group-containing) within a single particle structure. This composite approach allows the particle to exhibit both strong adhesion properties and rapid entanglement capabilities, simultaneously achieving fixability and film formation stability.
2Strength
If resin particles with core-shell structure are used to improve abrasion resistance, then image durability improves, but the resin particles fail to entangle and form stable films adequately
Solution Approach 1:
The core region with aromatic groups provides abrasion resistance through strong adhesion, while the shell region with ionic groups enables rapid entanglement for stable film formation. This spatial separation of functions resolves the contradiction between durability and film stability.
Solution Approach 2:
By combining aromatic-group-containing monomer units and ionic-group-containing monomer units in a core-shell composite structure, the resin particle achieves both high abrasion resistance and excellent film formation stability through the synergistic interaction of different functional groups.
3Reliability
If aromatic-group-containing ethylenically unsaturated monomer units are increased to improve adhesion, then fixability improves, but entanglement and film formation become insufficient
Solution Approach 1:
The invention concentrates aromatic-group-containing monomer units in the core region for adhesion, while concentrating ionic-group-containing monomer units in the shell region for entanglement. This local quality differentiation resolves the contradiction by preventing aromatic groups from interfering with entanglement processes.
Solution Approach 2:
The resin particle is segmented into core and shell regions with different functional group compositions. This segmentation allows aromatic groups to fulfill adhesion functions without hindering the entanglement process, which is facilitated by ionic groups in the shell region.
Data Source
AI summary
An aqueous ink for ink jet including a resin particle. The resin particle includes a first layer and a second layer in this order from the inside to the outside thereof. The first layer is composed of a first resin, wherein the proportion of a unit derived from an aromatic-group-containing ethylenically unsaturated monomer in the first resin is 10% by mass or less. The second layer has a tetrahydrofuran-insoluble fraction of 10% by mass or more and is composed of a second resin having a unit derived from an aromatic-group-containing ethylenically unsaturated monomer and a unit derived from an ionic-group-containing ethylenically unsaturated monomer, wherein the proportion of the unit derived from the ionic-group-containing ethylenically unsaturated monomer in the second resin is 3% by mass or more to 70% by mass or less.