Water-based pigment inks

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Solution Overview

Problem

Current water-based inks for inkjet printing on non-porous substrates, such as plastic, lack the necessary properties for industrial applications, including good jetting performance, image quality, storage stability, and film-forming properties without chemical pre-treatment.

Innovation Solution

Development of water-based pigment inks using a poly(styrene-maleic acid) co-polymer or poly(styrene-maleamic acid) co-polymer as a dispersant, surfactant, and binder, which allows for direct printing on non-chemically treated substrates with improved adhesion and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If water-based inks are used for inkjet printing on non-porous substrates, then environmental friendliness and cost are improved, but adhesion and film-forming properties deteriorate

Engineering Contradiction:
Improveenvironmental friendlinessVSAvoidadhesion
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent changes the chemical parameters of the ink formulation by using poly(styrene-maleic acid) co-polymer with high acid value (≥225 mg KOH/g) to improve adhesion to non-porous substrates while maintaining water-based environmental benefits. The high acid content enables chemical interaction with the substrate surface.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite polymer system combining poly(styrene-maleic acid) co-polymer with specific pigment particles and surfactants to achieve both environmental compatibility and strong adhesion. The co-polymer structure provides multiple functional groups for different purposes.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If complex polymer dispersants are used to improve ink stability, then ink storage stability is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveink storage stabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent extracts and utilizes the high acid value property of poly(styrene-maleic acid) co-polymer as the key stabilizing mechanism, eliminating the need for complex multi-component dispersant systems. This simplifies manufacturing while maintaining stability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the critical parameter of acid value to ≥225 mg KOH/g, which provides sufficient stability through a single polymer type rather than requiring complex formulations, thereby reducing manufacturing complexity.

Inventive Principle:
Principle #35Parameter changes

3Strength

If chemical pre-treatment is applied to substrates, then adhesion is improved, but process time and cost increase

Engineering Contradiction:
ImproveadhesionVSAvoidprocess time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The patent incorporates preliminary action by pre-functionalizing the ink formulation with high acid value poly(styrene-maleic acid) co-polymer, which provides built-in adhesion capability that eliminates the need for separate substrate pre-treatment steps.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The ink formulation performs self-service by containing all necessary adhesion-promoting components (high acid value co-polymer) that enable direct bonding to non-porous substrates without requiring external pre-treatment processes.

Inventive Principle:
Principle #25Self-service

4Strength

If polymer solids content is increased to improve film-forming properties, then film robustness is improved, but jetting performance and resolubility deteriorate

Engineering Contradiction:
Improvefilm robustnessVSAvoidjetting performance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the critical parameter of acid value to ≥225 mg KOH/g, which allows effective film formation at low polymer solids content (0.5-5%). The high acid content enhances polymer-substrate interaction efficiency, reducing the quantity of polymer needed.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite system where high acid value poly(styrene-maleic acid) co-polymer works synergistically with pigments and surfactants to achieve robust film formation at low concentrations, maintaining jetting performance.

Inventive Principle:
Principle #40Composite materials

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 inks exhibit excellent jetting performance, storage stability, and film-forming properties, enabling reliable industrial inkjet printing on non-porous substrates without the need for chemical primers or pre-treatment, with low polymer solids and high acid values contributing to their effectiveness.

Implementation Method 1

a polymeric dispersant which is a co-polymer of styrene-maleic acid

Methodology Applied
Scientific EffectDispersion: Dispersion (of waves)

Implementation Method 2

a polymeric dispersant which is a co-polymer of styrene-maleic acid and additionally at least a polyurethane binder and a surfactant

Methodology Applied
Scientific EffectSurfactant action: Surfactant

Implementation Method 3

direct printing on non-chemically treated substrates with improved adhesion

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentUS11795337B2Water-based pigment inks
Publication Date: 2023.10.24 SUN CHEMICAL CORP

AI summary

The present invention relates to a printing ink composition comprising a polymer selected from a poly(styrene-maleic acid) co-polymer having an acid number of ≥225 mg KOH/g, a poly(styrene-maleamic acid) co-polymer having an acid number of ≥225 mg KOH/g or a combination thereof, wherein the co-polymer is a lithium, sodium, potassium, ammonium or quaternary ammonium salt or combinations thereof. The printing ink composition is suitable for directly printing onto non-porous substrates particularly without the need for a chemical primer layer or chemical pre-treatment.