Inkjet-Receptive Coating Composition for Substrates

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Solution Overview

Problem

Existing inkjet printing technologies face challenges in achieving effective ink absorption and retention on substrates, leading to issues with image quality and durability.

Innovation Solution

A coating composition comprising poly(diallyldimethyl ammonium chloride), a crosslinkable cationic polymer, colloidal silica, silica gel, a binder such as vinyl acetate-ethylene copolymer, and water, which forms a matte-finished inkjet coating on substrates like polyester, vinyl, and paper, enhancing inkjet image quality with rapid drying, low color density loss, and water resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional inkjet printing is used on substrates, then the printing process is simple, but the ink absorption and retention are insufficient leading to poor image quality

Engineering Contradiction:
Improveimage qualityVSAvoidcoating composition complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-treating the substrate surface with a specially formulated coating composition before inkjet printing. This coating layer is applied in advance to modify the substrate surface properties, creating optimal conditions for subsequent ink absorption and retention. The coating contains cationic polymers, colloidal silica, and binders that are prepared and applied before the printing process to ensure proper ink interaction.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent employs composite materials by formulating a multi-component coating composition that combines cationic polymers (such as poly(diallyldimethyl ammonium chloride) and crosslinkable cationic copolymers), colloidal silica, silica gel, and binder resins (vinyl acetate-ethylene copolymer). This composite formulation creates a synergistic effect where each component contributes specific properties: cationic polymers for ink attraction, silica particles for surface structure and absorption, and binders for adhesion, collectively achieving superior inkjet receptivity and image quality.

Inventive Principle:
Principle #40Composite materials

2Reliability

If a coating composition is applied to improve ink absorption, then ink retention improves, but the coating process and composition formulation become more complex

Engineering Contradiction:
Improveink retentionVSAvoidcoating composition formulation
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by carefully controlling and optimizing the concentrations of each component in the coating formulation, the particle size distribution of silica materials, the molecular weight and charge density of cationic polymers, and the crosslinking degree of the coating film. These parameter optimizations ensure reliable ink retention while managing formulation complexity through systematic control of key variables rather than arbitrary composition.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The coating composition acts as an intermediary layer between the substrate and the inkjet ink. This intermediate coating modifies the interface properties, providing a controlled environment for ink deposition and absorption. The cationic polymers and binder resins in the coating mediate the interaction between the hydrophobic substrate surface and the ink, facilitating reliable ink retention without requiring direct modification of the substrate or complex ink formulations.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If rapid drying is achieved, then productivity increases, but ink absorption and color density may be compromised

Engineering Contradiction:
Improvedrying speedVSAvoidcolor density
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating a coating structure with different regions having distinct functions: the upper surface layer provides rapid water evaporation and drying properties for high productivity, while the lower layer and porous structure maintain high ink absorption capacity and color density retention. The colloidal silica and silica gel create a hierarchical pore structure that facilitates rapid moisture escape while trapping ink molecules, achieving both fast drying and excellent color density locally within different coating zones.

Inventive Principle:
Principle #3Local quality

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 coating composition ensures excellent ink absorption and retention, resulting in high-quality, water-resistant, and adhesive inkjet images with improved color density and rapid drying on various substrates.

Implementation Method 1

an ability to absorb and retain the ink effectively

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

forms a matte-finished inkjet coating on substrates... rapid drying

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentUS7651748B2Coating compositions for forming inkjet-receptive coatings on a substrate
Publication Date: 2010.01.26 ISP INVESTMENTS LLC

AI summary

An inkjet coating composition for coating a substrate to absorb ink from an inkjet printer comprises a combination of (a) polydiallyldimethyl ammonium chloride (pDADMAC), (b) a crosslinkable cationic polymer, (c) colloidal silica, (d) silica gel, (e) a binder, preferably vinyl acetate-ethylene copolymer, and (f) water.