Radiation Curable Ink with Dendritic Polyester Acrylate
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Solution Overview
Problem
Radiation curable inks face challenges with low adhesion and flexibility, particularly on a variety of substrates, due to the use of higher functional monomers that sacrifice adhesion for fast curing, limiting their application in inkjet printing.
Innovation Solution
The development of radiation curable ink compositions incorporating a dendritic and hyperbranched polyester acrylate component, combined with an oligomer and monomer component, which improves adhesion and flexibility, allowing for fast curing with low viscosity and reduced substrate heating, suitable for a wide range of substrates including polyolefins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher functional monomers are used to achieve fast curing, then curing speed is improved, but adhesion deteriorates
Solution Approach 1:
The patent changes the functional parameter of the acrylate monomers from high functionality (3+ functional groups) to low functionality (1-2 functional groups). This parameter change allows the ink to maintain fast curing speed through efficient UV polymerization while preserving adhesion properties, as lower functional monomers do not sacrifice flexibility and adhesion for curing speed like higher functional monomers do.
Solution Approach 2:
The patent creates a composite ink composition by combining low functional acrylate monomers (for adhesion and flexibility) with photoinitiators and colorants. This composite formulation achieves fast curing through the photoinitiator system while the low functional acrylate monomers maintain adhesion and flexibility, resolving the contradiction between curing speed and adhesion.
2Productivity
If higher functional monomers are used to achieve fast curing, then curing speed is improved, but flexibility deteriorates
Solution Approach 1:
The patent changes the functionality parameter of the acrylate monomers from 3 or higher to 1-2 functional groups. This parameter change maintains flexibility because lower functional monomers do not create excessive cross-linking that causes cracking when substrates are folded or wrinkled, while still enabling fast curing through efficient UV polymerization of the acrylate groups.
3Area of stationary object
If conventional inks are used on heat-sensitive substrates, then substrate coverage is achieved, but substrate damage occurs due to heating
Solution Approach 1:
The patent replaces conventional thermal drying mechanisms with UV photopolymerization. Instead of using heat to evaporate solvents and dry the ink (which damages heat-sensitive substrates), the ink uses UV-responsive photoinitiators to trigger rapid polymerization and curing at room temperature. This substitution of the drying mechanism eliminates substrate heating while achieving complete substrate coverage.
4Reliability
If low functional acrylate monomers are used, then adhesion and flexibility are improved, but curing speed deteriorates
Solution Approach 1:
The patent introduces photoinitiators as intermediaries to enable fast curing of low functional acrylate monomers. The photoinitiators absorb UV energy and generate radicals that rapidly initiate polymerization of the acrylate groups. This intermediary system allows the low functional monomers (which inherently cure slower) to achieve fast curing speeds without sacrificing adhesion and flexibility.
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 compositions demonstrate enhanced adhesion and flexibility, with elongation of 70% to 200%, and low viscosity, enabling effective curing on heat-sensitive substrates and a broad range of materials without premature peeling or cracking.
Implementation Method 1
Radiation curable ink compositions... fast curing speed... cured with a certain amount of UV energy
Implementation Method 2
The ink performance... are highly dependent on the ink compositions... cured with a certain amount of UV energy
Data Source
AI summary
The radiation curable ink compositions exhibit fasting curing, high flexibility and good adhesion to a broad range of substrates. The ink compositions include a dendritic or hyperbranched polyester acrylate component, which is present in an amount of 10-45% by weight and has a functionality of greater than 5. The compositions further include an oligomer component, a monomer component, a photoinitiator component, a colorant component, and an additive component. The compositions have a viscosity of not greater than 40cP at 25°C. The radiation curable compositions are suitable for inkjet printing on a variety of substrates.