UV Flexo Ink Adhesion via Polyurethane and Phosphate Esters

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Solution Overview

Problem

Energy curable inks and coatings exhibit poor adhesion to certain substrate films, such as bi-axially oriented polypropylene (BOPP) and polyethylene terephthalate (PET), which hampers their use in flexographic printing.

Innovation Solution

Incorporating a water-soluble or dispersible inert polyurethane resin and a water-soluble or dispersible phosphate ester into the energy curable compositions, which improves adhesion to these substrates while maintaining printability and opacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If inert polyurethane resin is added to improve adhesion to BOPP, then adhesion is improved, but printability deteriorates when too much resin is added

Engineering Contradiction:

ImproveadhesionVSAvoidprintability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent optimizes the concentration parameter of inert polyurethane resin to a specific range (0.1-15 wt%) and introduces phosphate ester at controlled concentrations (0.1-5 wt%), transforming the qualitative relationship between resin amount and adhesion into a quantitative optimization problem with clear parameter boundaries that balance adhesion improvement and printability maintenance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite adhesion promotion system by combining inert polyurethane resin with phosphate ester, where the synergistic interaction between these two materials achieves superior adhesion to BOPP while maintaining printability, overcoming the limitations of using polyurethane resin alone

Inventive Principle:

Principle #40Composite materials

2Reliability

If more inert polyurethane resin is added to improve adhesion, then adhesion to PET is improved, but the ink becomes difficult to print

Engineering Contradiction:

Improveadhesion to PETVSAvoidprintability

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent establishes optimal parameter ranges for both inert polyurethane resin (0.1-15 wt%) and phosphate ester (0.1-5 wt%), creating a formulation window that maximizes adhesion to PET while preserving printability through precise control of compositional parameters

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Phosphate ester acts as an intermediary substance that facilitates the interaction between the inert polyurethane resin and the PET substrate, enhancing adhesion while the controlled addition of phosphate ester prevents negative impacts on printability

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP4150019B1Adhesion promoters for UV flexographic inks and coatings

Publication Date: 2023.09.27 SUN CHEMICAL CORP

AI summary

The present invention provides water-based energy curable compositions that exhibit improved printability, adhesion, opacity, and wash-up properties. The compositions comprise one or more inert water-based polyurethane resins and one or more water-based phosphate esters. Addition of the inert polyurethane resins and phosphate esters improves adhesion of the energy curable compositions to a variety of substrates.