Microcapsule Shell Cross-Linking for Ink Jetting and Weather Fastness
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Solution Overview
Problem
Existing ink jet inks with microcapsules containing isocyanate compounds with aromatic rings form coarse particles, leading to poor jetting properties and weather fastness, while microcapsules without polymerizable groups fail to form films.
Innovation Solution
A microcapsule with a three-dimensional cross-linked shell containing a hydrophilic group and a polymerizable group, such as an epoxy or blocked isocyanate group, is developed, which suppresses the formation of coarse particles and enhances jetting properties and weather fastness by forming a film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If aromatic isocyanate compound is used as raw material for forming microcapsule, then microcapsule can be formed easily, but coarse particles are formed and jetting properties deteriorate
Solution Approach 1:
The invention changes the chemical structure parameter of the isocyanate compound from aromatic to non-aromatic (aliphatic or alicyclic). This parameter change reduces the reactivity of the isocyanate compound, preventing excessive reaction rates that lead to coarse particle formation, while still allowing microcapsule formation to proceed effectively.
2Ease of manufacture
If aromatic isocyanate compound is used as raw material, then microcapsule formation is facilitated, but weather fastness deteriorates
Solution Approach 1:
The invention changes the chemical stability parameter by selecting non-aromatic isocyanate compounds (aliphatic or alicyclic) that exhibit superior weather fastness and resistance to degradation from UV light, oxidation, and hydrolysis compared to aromatic isocyanate compounds, while maintaining adequate reactivity for microcapsule formation.
3Ease of manufacture
If microcapsule without polymerizable group is used, then manufacturing is simplified, but film formation capability is lost
Solution Approach 1:
The invention merges two previously separate functionalities into a single microcapsule structure: (1) the microcapsule shell formed from non-aromatic isocyanate compound, and (2) polymerizable groups (vinyl, acrylic, or epoxy groups) incorporated into the shell. This combination enables both simplified manufacturing (avoiding aromatic compounds) and film formation capability (through polymerizable groups) to coexist.
Solution Approach 2:
The microcapsule shell is designed to serve multiple functions simultaneously: it provides structural integrity as a microcapsule shell, offers weather fastness through non-aromatic chemistry, and enables film formation through incorporated polymerizable groups. This multi-functionality eliminates the need for separate components or post-treatments.
4Adaptability or versatility
If microcapsule with polymerizable group is used, then film formation is enabled, but manufacturing complexity increases
Solution Approach 1:
The polymerizable groups are incorporated directly into the microcapsule shell during the microcapsule formation process itself, rather than requiring separate coating or treatment steps. This merging of functions occurs in a single manufacturing process, avoiding additional equipment or process complexity.
Solution Approach 2:
The polymerizable groups are pre-incorporated into the microcapsule shell structure during microcapsule synthesis. This preliminary incorporation eliminates the need for subsequent coating or modification steps, simplifying the overall manufacturing process despite the enhanced functionality.
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 microcapsule achieves excellent jetting properties and weather fastness when used as an ink jet ink, with improved film formation and stability under various environmental conditions.
Implementation Method 1
the core contains at least one chemically reactive compound that is irradiated with ultraviolet rays so as to form a reaction product and contains a photopolymerization initiator
Data Source
AI summary
Provided are a microcapsule including a shell that has a three-dimensional cross-linked structure containing a hydrophilic group and Structure (1) and including a core that is in the interior of the shell, in which at least one of the shell or the core has a polymerizable group; and an application thereof. In Structure (1), X represents a (p + m + n)-valent organic group formed by linking at least two groups selected from -NH-, >N-, -C(=O)-, -O-, -S-, and an aliphatic hydrocarbon group which may have a ring structure, provided that an organic group having an aromatic ring is excluded from X, R1 to R3 represent an aliphatic hydrocarbon group having 5 to 15 carbon atoms which may have a ring structure, provided that an aliphatic hydrocarbon group having an aromatic ring is excluded from R1 to R3, and * represents a binding position, each of p, m, and n is equal to or greater than 0, and p + m + n equals 3 or greater.