Curable Coating Composition for Soft Touch Printing
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Solution Overview
Problem
Existing curable compositions for soft touch coatings in printing machines face limitations such as limited shelf-life, long curing times, poor protective properties, and the use of unhealthy isocyanates and large amounts of water or organic solvents, which hinder their application in printing machines.
Innovation Solution
A curable composition based on ethoxylated triacrylates and alkylglycidyletheracrylates, combined with a polymerization initiator, that can be processed without significant solvent addition, offering a one-part system with improved adhesion, chemical resistance, and reduced curing time, suitable for conventional printing machines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two-part curable compositions based on isocyanate chemistry are used, then soft touch coatings can be obtained, but shelf-life is limited and curing times are long
Solution Approach 1:
The patent changes the chemical parameters by replacing isocyanate-based two-part systems with a one-part composition using ethoxylated triacrylates and alkylglycidyletheracrylates. This parameter change enables single-component formulation that eliminates the need for mixing while achieving comparable soft touch coating quality with significantly reduced curing time through UV or electron beam irradiation.
Solution Approach 2:
The invention segments the curing process from the storage process by using a one-part system that remains stable during storage and only activates upon irradiation. This segmentation allows the composition to maintain shelf-life while enabling rapid curing when needed, resolving the contradiction between stability and reactivity.
2Ease of operation
If curable compositions contain large amounts of water or organic solvents, then processing ease improves, but printing speed decreases due to removal requirements
Solution Approach 1:
The patent changes the solvent content parameter by formulating a composition with minimal or no water/organic solvents. The low viscosity and good flow properties are achieved through the specific molecular structure of ethoxylated triacrylates and alkylglycidyletheracrylates, allowing easy processing without requiring solvent removal steps that would slow down production.
3Adaptability or versatility
If isocyanate-based curable compositions are used, then coating flexibility is achieved, but harmful emissions occur
Solution Approach 1:
The patent converts the harmful isocyanate chemistry into a beneficial alternative by using ethoxylated triacrylates and alkylglycidyletheracrylates that provide comparable coating flexibility and performance without the harmful emissions. The epoxy-acrylate chemistry offers the same adaptability while being environmentally friendly and suitable for indoor printing applications.
4Productivity
If curable compositions are designed for rapid curing, then productivity improves, but adhesion and chemical resistance may be compromised
Solution Approach 1:
The patent uses a composite chemical system combining ethoxylated triacrylates (providing rapid polymerization and adhesion) with alkylglycidyletheracrylates (providing chemical resistance and flexibility). This composite formulation achieves rapid curing through the acrylate groups while the epoxy groups contribute to excellent adhesion, chemical resistance, and mechanical properties, resolving the contradiction between speed and performance.
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 curable composition provides soft touch coatings with enhanced shelf-life, short curing times, robust adhesion, and improved chemical and scratch resistance, eliminating the need for excessive solvents and enabling efficient processing in printing machines.
Implementation Method 1
The polymerization initiator is preferably selected from photoinitiators and thermal free-radical initiators. Photoinitiators are compounds which form free radicals upon exposure to radiation, in particular UV radiation.
Implementation Method 2
curing by exposure to radiation, in particular visible radiation, UV radiation, electron-beam radiation or microwave radiation
Data Source
AI summary
The invention relates to curable compositions based on ethoxylated triacrylates and alkylglycidyletheracrylates which can be employed to obtain printing products with a soft touch coating. The curable compositions of the invention can easily be processed in conventional printing machines.