High Opacity White Ink for Packaging via Composite Resin System
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Solution Overview
Problem
Current white inks used in packaging face challenges such as decreased opacity when over-coated with lacquers or adhesives, and the commercial infeasibility of using high TiO2 load levels to achieve higher opacity while maintaining low viscosity.
Innovation Solution
A high opacity solvent-based white printing ink composition is developed, comprising 5-15% alcohol soluble polyester resins, 35-75% TiO2 pigment, and a solvent comprising one or more alcohol solvents, which maintains low viscosity and high TiO2 content, and retains opacity when over-coated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If higher load levels of TiO2 pigment (higher than 50 wt %) are used to increase opacity and hiding power, then opacity is improved, but viscosity increases making the ink commercially infeasible for flexographic or gravure printing
Solution Approach 1:
The patent changes the chemical parameters of the binder system by using a specific combination of polyester resin (5-15 wt%), polyurethane resin (10-30 wt%), and acrylic resin (5-20 wt%), along with controlled solvent composition (5-20 wt% water, 10-30 wt% alcohol), to achieve optimal solubility and dispersion that enables high TiO2 loading without excessive viscosity increase
Solution Approach 2:
The patent employs a composite binder system combining multiple resin types (polyester, polyurethane, acrylic) with complementary properties, where polyester provides opacity enhancement, polyurethane provides flexibility and adhesion, and acrylic provides durability, creating a synergistic effect that manages viscosity while maintaining high pigment load
2Adaptability or versatility
If currently available white inks are over-coated with a lacquer or adhesive, then packaging functionality is improved, but opacity levels decrease
Solution Approach 1:
The patent performs preliminary optimization of the ink formulation before over-coating occurs, incorporating specific resin combinations and surface treatment agents that create a stable, high-opacity film structure resistant to opacity reduction when subsequent lacquer or adhesive layers are applied
Solution Approach 2:
The patent enhances local quality at the pigment-binder interface through surface treatment of TiO2 particles and selective resin-pigment interactions, creating localized regions of strong adhesion and light scattering that maintain opacity even when over-coated
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 ink achieves high opacity and low viscosity, retaining over 90% of its opacity after being over-coated with lacquer or adhesive, and can be used in flexographic or gravure printing for packaging applications.
Implementation Method 1
5 to 15% by weight, based on the total weight of the ink composition, of a resin component, wherein the resin component comprises one or more alcohol soluble polyester resins
Data Source
AI summary
The present invention provides a high opacity solvent based white ink or coating composition that provides high levels of opacity to substrates used for packaging materials that are printed via flexography or gravure. The ink or coating composition contains up to 75 wt % titanium dioxide, while still having a viscosity suitable for flexographic and gravure printing methods.