Amine Co-initiator Mixture for UV Curing

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Solution Overview

Problem

Radiation-curable compositions containing photoinitiators and co-initiators face issues with migration and toxicity due to residual additives in food packaging, and existing high molecular weight, diffusion-hindered co-initiators suffer from low photoactivity and solubility problems.

Innovation Solution

A high molecular weight, diffusion-hindered amine co-initiator mixture comprising an aminobenzoate derivative and ancillary amines, which exhibits high co-initiator efficiency, solubility in acrylate resins, and reduced migration, while maintaining low toxicity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If high molecular weight, diffusion-hindered co-initiators are used to reduce migration, then migration and toxicity are reduced, but photoactivity and solubility deteriorate

Engineering Contradiction:

Improvemigration and toxicityVSAvoidphotoactivity and solubility

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The invention divides the co-initiator system into two segments: a high molecular weight diffusion-hindered amine component (for low migration) and a low molecular weight reactive amine component (for high photoactivity). This segmentation allows each component to fulfill its specific function optimally while working synergistically together.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention creates a composite co-initiator system combining two chemically distinct amine components with different molecular weights and properties. The composite mixture achieves a balance between migration resistance and photoactivity that neither component could achieve alone.

Inventive Principle:

Principle #40Composite materials

2Productivity

If conventional low molecular weight amine co-initiators are used for high photoactivity, then UV-curing efficiency is improved, but migration and toxicity increase

Engineering Contradiction:

ImproveUV-curing efficiencyVSAvoidmigration and toxicity

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The co-initiator system is segmented into functional roles: the low molecular weight amine provides rapid UV-curing efficiency through high photoactivity, while the high molecular weight diffusion-hindered amine suppresses migration and toxicity. This functional segmentation resolves the contradiction between curing efficiency and safety.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The high molecular weight diffusion-hindered amine acts as an intermediary component that mediates between the reactive low molecular weight amine and the polymer matrix. It reduces the mobility and potential harm of the reactive amine while maintaining its photoactive functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If high concentrations of amine co-initiator are used to reduce oxygen inhibition, then surface cure quality is improved, but migration likelihood increases

Engineering Contradiction:

Improvesurface cure qualityVSAvoidmigration

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the molecular weight parameter of the amine co-initiator system by incorporating high molecular weight diffusion-hindered amines. This parameter change allows achieving surface cure quality at lower effective concentrations, thereby reducing migration while maintaining reliability.

Inventive Principle:

Principle #35Parameter changes

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 co-initiator mixture demonstrates enhanced solubility and reactivity in UV-curing processes, with reduced migration and toxicity, comparable to or better than existing polymeric amine co-initiators, and promotes rapid UV-curing with improved compatibility in radiation-curable compositions.

Implementation Method 1

Radiation-curable compositions containing acrylate esters and other similar unsaturated compounds can be polymerised by exposure to ultraviolet (UV) light. For rapid, effective curing a photoinitiator is often necessary, which forms radical species upon irradiation with photons and initiates free-radical polymerisation of unsaturated groups

Methodology Applied

Scientific EffectPhotopolymerisation: Photopolymerisation

Implementation Method 2

Interaction between Type-II photoinitiators and appropriate co-initiators upon exposure to UV radiation leads to the generation of radical species which can initiate the polymerisation of UV-curable resins

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 3

A diffusion-hindered photoinitiator or co-initiator is a photoactive molecule which exhibits low mobility in a cured layer of the curable composition or ink, thus reducing its propensity to migrate. As described in the literature the ability of a molecule to migrate is often determined by its molecular weight. Therefore, for a low migration UV-curable ink or coating, photoactive components having a molecular weight of greater than 500 Daltons are preferred

Methodology Applied

Scientific EffectDiffusion: Diffusion

Data Source

PatentUS12146010B2Amine co-initiator mixture

Publication Date: 2024.11.19 ARKEMA FRANCE SA

AI summary

The invention relates to a co-initiator comprising the aminobenzoate derivative according to Formula (I) and at least one ancillary amine, wherein the reactivity and solubility of said co-imitator in UV-curable resins is sufficiently high that the co-initiator can be used in UV radiation curing processes. Formula (I) wherein R1 and R2 independently represent methyl or ethyl groups; and j, k, l and m are independently 0 to 20.