Cationic Resin Treatment Liquid for Inkjet Beading and Density
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Solution Overview
Problem
Existing treatment liquids for inkjet recording, particularly those containing cationic resins, cause skin irritation, sensitization, and image smearing due to high cationization degrees, and result in beading and medium tearing when used on non-ink absorbent or low absorbency recording media.
Innovation Solution
A treatment liquid comprising a water-soluble organic solvent, at least two cationic resins with a cationization degree of 4 meq/g or greater at pH 4.0 and weight average molecular weights between 5,000 to 25,000, which react with carboxyl group-containing resins in the aqueous recording ink to aggregate colorants, preventing beading and improving image density while ensuring safety and reducing friction between recording media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a cationic resin with high cationization degree is used to aggregate colorant and prevent beading, then image density is improved, but skin irritation and sensitization increase
Solution Approach 1:
The patent optimizes the cationization degree parameter to a specific range (3.0-6.0 meq/g) rather than using high cationization degrees, and controls the molecular weight within 5,000-25,000 range. This parameter optimization maintains colorant aggregation capability while reducing skin irritation and sensitization effects.
Solution Approach 2:
The patent uses a composite approach by combining multiple cationic resins with different molecular weights and/or cationization degrees in the treatment liquid. This composite material strategy allows achieving effective colorant aggregation while balancing safety requirements through the synergistic effects of different resin components.
2Manufacturing precision
If a cationic resin with high cationization degree is used to aggregate colorant, then beading is prevented, but friction coefficient between recording media increases causing smearing and tearing
Solution Approach 1:
The patent controls the molecular weight parameter of cationic resins within 5,000-25,000 range, which optimizes the balance between colorant aggregation capability and friction characteristics. This parameter control prevents beading while maintaining acceptable friction coefficients that avoid smearing and tearing.
Solution Approach 2:
The patent employs composite materials by combining multiple cationic resins with different molecular weights and properties. This composite approach enables the treatment liquid to achieve effective colorant aggregation while maintaining suitable friction characteristics through the combined effects of different resin components.
3Device complexity
If only one cationic resin is used in treatment liquid, then formulation is simple, but image density and beading resistance are insufficient
Solution Approach 1:
The patent uses a composite material strategy by combining multiple cationic resins with different molecular weights and/or cationization degrees. This composite approach enhances colorant aggregation capability and improves image density while maintaining reasonable formulation complexity through systematic selection of resin components.
4Manufacturing precision
If cationic resin with molecular weight of 1,000 or less is used, then beading is prevented, but safety is compromised
Solution Approach 1:
The patent optimizes the molecular weight parameter to a specific range (5,000-25,000) that balances beading resistance and safety requirements. This parameter optimization ensures effective colorant aggregation while maintaining acceptable safety profiles, avoiding the use of excessively low molecular weight resins that compromise safety.
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 solution effectively aggregates colorants, prevents beading, and enhances image density while ensuring safety and reducing friction between recording media, thus improving the overall quality and durability of inkjet recordings.
Implementation Method 1
a cationic resin has an index, which is called a cationization degree, and indicates the strength of cationy. The ability of aggregating a colorant in an aqueous recording ink is higher, as the cationization degree is higher.
Data Source
AI summary
A treatment liquid, which contains a water-soluble organic solvent, at least two cationic resins, and water, wherein the cationic resins have a cationization degree of 4 meq/g or greater at pH of 4.0, and a repeating unit represented by the following structural formula 1:and the cationic resins have mutually different weight average molecular weights in the range of 5,000 to 25,000.