Photocurable Ink for Automotive Glass with High Optical Density
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Solution Overview
Problem
Existing inks used for decorating display cover glass in automotive interiors suffer from deficiencies such as requiring multiple layers for desired optical density, having low production throughput, and failing to provide adequate adhesion to the glass under varying environmental conditions.
Innovation Solution
A photocurable ink comprising at least 10 wt % pigment, with a thickness of less than or equal to 25 μm and an optical density of greater than or equal to 4.0, which after curing exhibits a pencil hardness of greater than or equal to 3H and adhesion to the glass substrate of greater than or equal to 4B even after exposure to high temperature and humidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing inks are applied through screen-printing process, then adhesion to glass substrate is achieved, but production throughput is low and multiple layers are required to provide desired optical density
Solution Approach 1:
The patent changes the chemical composition parameters of the ink by incorporating specific photoinitiators, reactive monomers, and pigments in optimized ratios. This enables the ink to achieve high optical density (OD ≥ 4.0) in a single thin layer (≤ 25 μm) while remaining compatible with inkjet printing processes, thereby increasing productivity and reducing structural complexity
Solution Approach 2:
The patent replaces the mechanical screen-printing process with a photocurable inkjet printing system. The ink is deposited as a thin film and then cured through UV-LED irradiation, eliminating the need for manual screen printing operations and enabling automated high-throughput production with single-layer application
2Length of stationary object
If UV-curable inks are used to achieve desired optical density, then thickness is reduced, but adhesion to glass substrate deteriorates under environmental testing conditions
Solution Approach 1:
The patent creates a composite material system combining reactive monomers (such as acrylates), photoinitiators, and pigments in specific proportions. This composite formulation enables the ink to form a thin opaque layer (≤ 25 μm) that maintains strong adhesion to glass substrates even after exposure to high temperature and humidity conditions, resolving the contradiction between thickness reduction and adhesion maintenance
Solution Approach 2:
The patent optimizes chemical composition parameters including monomer molecular weight, photoinitiator concentration, and pigment dispersion characteristics. These parameter adjustments enable the formulation of a photocurable ink that cures to form a thin, adherent, and environmentally stable opaque layer, achieving both reduced thickness and maintained reliability
3Manufacturing precision
If multiple layers of ink are applied to achieve desired optical density, then optical density is improved, but production time increases and throughput decreases
Solution Approach 1:
The patent fundamentally changes the ink composition parameters to include high-concentration pigment dispersions, optimized photoinitiator packages, and reactive monomers that provide rapid cure kinetics. This enables the deposition of a single thin layer (≤ 25 μm) that achieves high optical density (OD ≥ 4.0) upon UV-LED curing, eliminating the need for multiple coating passes and thereby maximizing production throughput while maintaining manufacturing precision
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 photocurable ink achieves high optical density and adhesion to the glass substrate, ensuring reliable performance under environmental testing conditions, while also being compatible with high-throughput inkjet printing processes and free from environmentally harmful solvents.
Implementation Method 1
after curing via exposure to curing light from an ultraviolet light ('UV') light emitting diode ('LED')
Data Source
AI summary
Described herein is a glass article comprising a glass substrate having a major surface and an opaque layer disposed on the major surface. The opaque layer comprises a photocurable ink that comprises at least 10 wt % of a pigment. The opaque layer comprises a thickness of less than or equal to 25 μm and an optical density of greater than or equal to 4.0. After curing via exposure to curing light from an ultraviolet light (“UV”) light emitting diode (“LED”), the opaque layer exhibits: (a) a pencil hardness of greater than or equal to 3H when measured according to ASTM 3363, and (b) an adhesion to the glass substrate of greater than or equal to 4B after being subjected to a temperature of 85° C. at 95% relative humidity for a period of at least 500 hours, when tested according to ASTM 3359.