Microcapsule-Encapsulated Peroxo Drying Agent for Intaglio Ink

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Solution Overview

Problem

Oxidative printing inks used in intaglio printing have a short pot life, leading to inefficiencies and high waste due to the need for frequent ink replacement, and struggle with drying unevenness in thick layers and on heat-sensitive substrates, which complicates the process and increases disposal costs.

Innovation Solution

A printing ink with microcapsules containing a peroxo compound core material, encapsulated in a stable capsule shell that can be opened by pressure, temperature, or UV radiation to initiate drying, ensuring even drying and extending the pot life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If oxidative printing inks are used in intaglio printing, then the ink can be disposed of more economically and is suitable for heat-sensitive substrates, but the pot life is short leading to frequent ink replacement and high waste

Engineering Contradiction:
Improveink wasteVSAvoidpot life
Core Design Contradiction:
Loss of substanceVSDuration of action of moving object

Solution Approach 1:

The peroxo compound is pre-encapsulated in microcapsules within the ink formulation, but the drying function is activated only when needed through pressure, temperature, or UV radiation. This preliminary preparation allows the ink to maintain stability during storage while enabling rapid drying when applied, thus extending pot life without compromising the economic disposal advantages of oxidative inks.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The microcapsule acts as an intermediary carrier that releases the peroxo compound only under specific activation conditions. This intermediary mechanism prevents premature drying while ensuring the drying function is available when needed, resolving the contradiction between extended pot life and the need for rapid drying in intaglio printing.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Speed

If traditional peroxo compounds are used as drying agents, then drying occurs quickly, but the compounds are chemically unstable and release oxygen automatically after a certain time, reducing pot life

Engineering Contradiction:
Improvedrying speedVSAvoidpot life
Core Design Contradiction:
SpeedVSDuration of action of moving object

Solution Approach 1:

The peroxo compound is pre-encapsulated in microcapsules within the ink formulation, but the drying function is activated only when needed through pressure, temperature, or UV radiation. This preliminary preparation allows the ink to maintain stability during storage while enabling rapid drying when applied, thus extending pot life without compromising the economic disposal advantages of oxidative inks.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The microcapsule shell provides a protective barrier that contains the peroxo compound until activation. The shell is designed to be penetrable by pressure, temperature, or UV radiation, allowing controlled release of the drying agent. This flexible encapsulation maintains chemical stability during storage while enabling rapid drying when activated, resolving the contradiction between drying speed and pot life.

Inventive Principle:
Principle #30Flexible shells and thin films

3Manufacturing precision

If thick ink layers are applied in intaglio printing, then the printing quality is improved, but the drying becomes uneven with deeper layers drying more slowly than upper layers

Engineering Contradiction:
Improveprinting qualityVSAvoiddrying uniformity
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The peroxo compound is distributed throughout the entire ink layer via the microcapsule dispersion, ensuring that drying agents are present in both upper and lower layers. When activated, this uniform distribution enables simultaneous drying throughout the thick ink layer, maintaining printing quality while achieving even drying that conventional surface-level drying agents cannot accomplish.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The microcapsule acts as an intermediary carrier that releases the peroxo compound only under specific activation conditions. This intermediary mechanism prevents premature drying while ensuring the drying function is available when needed, resolving the contradiction between extended pot life and the need for rapid drying in intaglio printing.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enables quick and even drying of intaglio printing layers, reducing waste and disposal costs, and improving the quality and durability of the printed layers by ensuring thorough drying without the need for additional activation steps.

Implementation Method 1

The polymerization of UV-curing ink systems is initiated by irradiation with UV-A or UV-B radiation. In oxidatively drying ink systems, polymerization is started by contact with oxygen.

Methodology Applied
Scientific EffectOxidative cross-linking: Oxidation

Implementation Method 2

the capsule shell can be opened by the action of pressure, temperature and/or UV radiation in order to trigger the drying process of the printing ink or varnish by releasing the core material

Methodology Applied
Scientific EffectMicrocapsule rupture:

Implementation Method 3

The polymerization of UV-curing ink systems is initiated by irradiation with UV-A or UV-B radiation

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 4

peroxo compounds were used previously. These compounds release an oxygen atom upon contact with water, thus initiating the oxidative cross-linking of printing ink layers even in the absence of atmospheric oxygen

Methodology Applied
Scientific EffectPeroxide decomposition:

Data Source

PatentEP3660110B1Printing ink or paint for safety printing, printed safety substrate and associated method
Publication Date: 2022.01.05 GIESECKE & DEVRIENT CURRENCY TECHNOLOGY GMBH
  • EP3660110B1 patent drawingFigure 1~4

AI summary

The invention relates to a printing ink (10) or varnish for security printing, comprising a binder (12) and a plurality of microcapsules (20) dispersed in the binder, the microcapsules having a capsule shell (22) and a core material (24) enclosed by the capsule shell, wherein the core material (24) is formed by a peroxide compound acting as a drying agent, and the capsule shell (22) can be opened by the application of pressure, temperature and/or UV radiation in order to trigger the drying process of the printing ink (10) or varnish by releasing the core material (24). The invention also relates to a printed security substrate and to methods for providing a security substrate with a fully cured intaglio printing layer.