UV Ink Composition Balancing Cure and Adhesion With Dark Pigments
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Solution Overview
Problem
Existing ink compositions face issues with poor cure performance and adhesion, particularly when using dark pigments like carbon black, leading to problems such as offsetting and image ghosting, especially in applications like food packaging.
Innovation Solution
An ink composition comprising a phosphine oxide initiator and benzyl acrylate, with specific limits on the amounts of mono-functional monomers and benzyl acrylate, enhancing solubility and mobility of the initiator to improve cure and adhesion properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phosphine oxide initiator is used in UV curable ink, then cure performance is improved, but solubility in common monomers is limited
Solution Approach 1:
The patent changes the chemical structure parameters of the photoinitiator from conventional phosphine oxides to bis-acyl phosphine oxide compounds, which have improved solubility characteristics in UV curable monomers while maintaining effective photoinitiation performance
Solution Approach 2:
The patent creates a composite photoinitiator system by combining bis-acyl phosphine oxide structures with specific monomer formulations, achieving both solubility and cure performance through material composition optimization
2Manufacturing precision
If dark pigments such as carbon black are used, then print quality is improved, but photoinitiator solubility and cure performance deteriorate
Solution Approach 1:
The patent modifies the photoinitiator molecular structure to bis-acyl phosphine oxide compounds with enhanced solubility parameters that allow effective UV absorption and initiation even in the presence of dark pigments that would otherwise shield conventional initiators
3Adaptability or versatility
If high amount of mono-functional monomers is used, then ink composition flexibility is improved, but adhesion and cure performance worsen
Solution Approach 1:
The patent optimizes the functional group ratio by limiting mono-functional monomers to less than 45 wt% and specifying benzyl acrylate content, creating a balanced composition that maintains formulation flexibility while ensuring adequate adhesion through controlled monomer functionality
Solution Approach 2:
The patent creates a composite monomer system combining benzyl acrylate with other monomers in specific ratios, achieving both composition flexibility and improved adhesion through synergistic material combinations
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 composition achieves good cure and adhesion, even with dark pigments, suitable for high-quality printing on food packaging, with improved solubility and mobility of the phosphine oxide initiator.
Implementation Method 1
the monomers polymerise to provide the cured printed deposit. The polymerization process is often referred to as curing, in the case of UV curable inks, the curing process involves treating the printed ink composition with UV radiation
Data Source
AI summary
Provided is an ink composition for use in drop on demand inkjet printing such as piezoelectric drop on demand inkjet printing. The ink composition has a phosphine oxide initiator and benzyl acrylate. The amount of benzyl acrylate is less than 40 wt % based on the total weight of the ink composition and the total amount of mono-functional monomers is less than 45 wt % based on the total weight of the ink composition. The phosphine oxide initiator is a bis-acyl phosphine oxide, a benzoyl alkyl phosphinate, or a mixture thereof. The ink compositions are suitable for radiation curing and have good cure properties or good adhesion properties.