Disc-Shaped Pigment Microstructure for Flexible Color-Shift Security Inks
Solution Overview
Problem
Existing color-changing pigments for screen printing are costly and limited in color palette, with color changes typically occurring from reddish to yellowish-green and not vice versa, and are difficult to achieve colorless or white appearances.
Innovation Solution
A platelet-shaped pigment with a layered structure comprising a carrier substrate, a transparent embossed varnish layer, a reflection-enhancing coating, and a translucent color layer, reflecting light in multiple spatial directions due to a relief structure with reflective mosaic elements, and optionally a flat metallized surface with different color layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional printing inks are used, then application is simple, but security features are insufficient and easily replicated
Solution Approach 1:
The printing process is segmented into multiple sequential steps (first printing, drying, second printing) with each layer containing different pigment types. This segmentation allows complex security features to be built up gradually rather than requiring all features in a single printing pass, resolving the contradiction between security reliability and process complexity.
Solution Approach 2:
The first pigment layer is printed and dried beforehand to establish a base layer with specific properties (e.g., non-metallic pigments for background). This preliminary action prepares the substrate for subsequent security feature layers, allowing complex security features to be added systematically without requiring all complexity in one step.
2Reliability
If multiple pigment layers are printed to create security features, then security reliability improves, but production time increases
Solution Approach 1:
The printing process is designed so that each pigment layer is applied and dried continuously in sequence without interruption. The first layer serves as preparation for the second, and both contribute to the final security feature simultaneously. This continuous multi-layer approach achieves high security reliability while minimizing total production time compared to sequential separate printing operations.
3Reliability
If specific pigment combinations are used for security features, then security reliability improves, but manufacturing complexity increases
Solution Approach 1:
The patent specifies precise pigment composition parameters including particle size ranges (0.1-10 μm), concentration ratios (first pigment 5-50 wt%, second pigment 50-95 wt%), and refractive index differences. These parameter specifications enable standardized manufacturing processes that produce reliable security features while maintaining ease of manufacture through consistent parameter control rather than complex procedural variations.
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 provides a cost-effective means to achieve versatile color changes, including colorless or white appearances, by reflecting light in multiple directions, enhancing color flexibility and applicability to security features and decorative uses.
Implementation Method 1
a first pigment and a second pigment are mixed, wherein the first pigment has a first particle size distribution and a first refractive index, and the second pigment has a second particle size distribution and a second refractive index
Implementation Method 2
the first pigment has a first particle size distribution and a first refractive index, and the second pigment has a second particle size distribution and a second refractive index
Data Source
Figure 1~3
Figure 4A~6
Figure 7a~9
AI summary
The invention relates to a disc-shaped pigment with a layered structure, having the following layers in this sequence: - optionally a substrate; - a transparent embossing varnish layer having an embossed relief structure; - a reflection-enhancing coating following the relief structure forming a reflective microstructure, wherein the reflective microstructure is present in the form of a mosaic of a plurality of reflective mosaic elements and the reflective mosaic elements do not reflect the incident light in the direction of the mirror reflection relative to the plane of the disc, but in a direction differing from this and each have a lateral dimension 1, that is greater than 2 μm.