Photoreactive Polymer for Radiation Curable Compositions

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Solution Overview

Problem

Radiation curable compositions for food packaging and ink-jet inks face challenges with low molecular weight photo-initiators and co-initiators, which can leach into food, causing health risks and increasing solution viscosity, limiting their effectiveness and compatibility with various applications.

Innovation Solution

The development of photoreactive polymers with a hyperbranched dendritic core containing both initiating and co-initiating functional groups, which are easy to manufacture and maintain low viscosity, thereby reducing extractable residues and enhancing compatibility with a wide range of radiation curable compositions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If low molecular weight photo-initiators and co-initiators are used in radiation curable compositions, then curing efficiency is improved, but extractable residues increase causing health risks

Engineering Contradiction:

Improvecuring efficiencyVSAvoidextractable residues

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent combines the photo-initiator and co-initiator functions into a single macromolecular structure. The polymer contains both initiating groups (Norrish type I or II) and co-initiating groups (amines or thiols) integrated within the same molecular framework, eliminating the need for separate low molecular weight components that can leach out

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the molecular weight parameter from low (conventional initiators) to high (macromolecular initiators with Mn > 1000 g/mol). This parameter change reduces extractability while maintaining curing efficiency through the integrated multifunctional design

Inventive Principle:

Principle #35Parameter changes

2Productivity

If low molecular weight co-initiators are used, then curing performance is improved, but solution viscosity increases limiting application

Engineering Contradiction:

Improvecuring performanceVSAvoidsolution viscosity

Core Design Contradiction:

ProductivityVSStress or pressure

Solution Approach 1:

The patent changes the molecular weight parameter to high values (Mn > 1000 g/mol, preferably > 5000 g/mol) which reduces solution viscosity while maintaining curing performance through the integrated multifunctional design. The macromolecular structure provides sufficient mobility for curing without the viscosity problems of low molecular weight initiators

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If higher molecular weight co-initiators are used to reduce extractable residues, then health safety is improved, but functionality decreases requiring larger amounts

Engineering Contradiction:

Improveextractable residuesVSAvoidfunctionality

Core Design Contradiction:

Object-affected harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent merges multiple functional groups (initiating groups and co-initiating groups) within a single macromolecular chain, achieving high functionality despite high molecular weight. The polymer contains multiple reactive sites per molecule, compensating for the reduced number of molecules per unit mass

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The macromolecular initiator serves multiple functions simultaneously: it acts as both photo-initiator and co-initiator, provides structural framework, and enables curing without requiring separate additive components. This multi-functionality maintains effectiveness despite high molecular weight

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

These polymers demonstrate equivalent or superior curing efficiency to low molecular weight combinations while maintaining low viscosity, making them suitable for food packaging and ink-jet inks without adverse effects on packaging materials or print quality.

Implementation Method 1

a) providing a photoreactive polymer, and b) admixing the said photoreactive polymer with monomers, oligomers and/or prepolymers

Methodology Applied

Scientific EffectPhotopolymerisation: Photopolymerisation

Implementation Method 2

The development of photoreactive polymers with a hyperbranched dendritic core containing both initiating and co-initiating functional groups, which are easy to manufacture and maintain low viscosity

Methodology Applied

Scientific EffectViscosity reduction through dendritic structure:

Implementation Method 3

When low molecular weight products are not built into the polymer network, they are prone to diffuse out of the cured composition and can readily be extracted

Methodology Applied

Scientific EffectLeaching resistance through molecular weight:

Data Source

PatentUS7507773B2Radiation curable compositions

Publication Date: 2009.03.24 AGFA NV

AI summary

A radiation curable composition comprising a novel photoreactive polymer is disclosed comprising a dendritic polymer core with at least one initiating functional group and at least one co-initiating functional group.Suitable radiation curable compositions are varnishes, lacquers, printing inks and radiation curable ink-jet inks. The dendritic polymeric core is preferably a hyperbranched polymer.