Polyurethane Printing Ink Varnish with Branched Amine Chain Extender
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Solution Overview
Problem
Conventional printing inks face challenges in achieving excellent laminate strength, blocking resistance, dot reproducibility, and plate clogging resistance, particularly in toluene-free systems, where dot reproducibility and plate clogging issues are unresolved.
Innovation Solution
A polyurethane-based printing ink varnish is developed using a polymeric polyol and polyisocyanate, with a polyfunctional amine containing secondary amino groups as a chain extender, allowing for uniform synthesis in an organic solvent and maintaining stability in solution form, which enhances laminate strength, blocking resistance, and plate clogging resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional polyurethane resins are used in toluene-free systems, then laminate strength and blocking resistance are improved, but dot reproducibility and plate clogging resistance deteriorate
Solution Approach 1:
The invention changes the chemical structure parameters of the polyurethane resin by introducing a branched structure with specific functional groups (hydroxyl, carboxyl, amine, or isocyanate groups) at predetermined positions. This structural modification enables the resin to maintain both laminate strength and dot reproducibility in toluene-free systems by controlling the resin's interaction with solvents and substrates through its branched architecture and functional group positioning.
Solution Approach 2:
The invention creates a composite polyurethane resin system combining polymeric polyol, polyisocyanate, and branched-chain compounds with specific functional groups. This composite structure integrates the advantages of different components: the polymeric polyol provides base properties, the polyisocyanate forms crosslinks for strength, and the branched-chain compounds with functional groups provide both laminate strength and dot reproducibility through their unique molecular architecture.
2Strength
If conventional polyurethane resins are used in toluene-free systems, then laminate strength and blocking resistance are improved, but plate clogging resistance deteriorates
Solution Approach 1:
The invention modifies the molecular parameters of the polyurethane resin by incorporating branched structures with specific functional groups that prevent aggregation and clogging. The branched architecture with hydroxyl, carboxyl, amine, or isocyanate groups at predetermined positions creates steric hindrance that prevents resin molecules from aggregating in the gravure cylinder, thereby maintaining plate clogging resistance while preserving blocking resistance through the same structural features.
3Strength
If polyfunctional amine is used as chain extender in aqueous emulsion polymerization, then laminate strength is improved, but solution-based resin synthesis becomes difficult
Solution Approach 1:
The invention introduces a branched-chain compound with specific functional groups (hydroxyl, carboxyl, amine, or isocyanate groups) as an intermediary chain extender in the polyurethane synthesis. This intermediary molecule mediates between the polymeric polyol and polyisocyanate, enabling controlled chain extension and crosslinking in solution-based systems while forming the branched structure necessary for laminate strength, thus solving the contradiction between synthesis ease 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 solution achieves superior laminate strength, blocking resistance, and plate clogging resistance while maintaining dot reproducibility, even in toluene-free systems, by utilizing a polyurethane resin with a branched structure that stabilizes pigment dispersion and prevents swelling.
Implementation Method 1
a polyurethane prepared using a polymeric polyol and a polyisocyanate as the main structural components, wherein the polyurethane is synthesized using, as a chain extender, a polyfunctional amine
Implementation Method 2
a polyurethane resin with a branched structure that stabilizes pigment dispersion and prevents swelling
Data Source
AI summary
The present invention relates to an oil-based printing ink varnish comprising a polyurethane prepared using a polymeric polyol and a polyisocyanate as the main structural components, wherein the polyurethane is synthesized using, as a chain extender, a polyfunctional amine which contains at least one secondary amino group in each molecule and in which the total of the number of primary amino groups and the number of secondary amino groups is 3 or more per molecule. The present invention is able to provide a printing ink varnish containing a non-aromatic organic solvent and having excellent laminate strength, blocking resistance, dot reproducibility and plate clogging resistance, as well as a laminate ink containing the varnish.