Phosphine Oxide Photoinitiators with Coumarin Sensitizers for Surface Curing

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Solution Overview

Problem

Phosphine oxide photoinitiators are less effective in achieving surface curing in photopolymerizable compositions, and the interaction of Type-I photoinitiators with sensitizers is unpredictable, necessitating the development of photoinitiator packages that enhance curing efficiency without new photoinitiator creation.

Innovation Solution

A photoinitiator package comprising mono- or bisacylphosphine oxide photoinitiators, coumarin-based sensitizers, and amines, which synergistically improve the curing process through the inclusion of amines with coumarin-based sensitizers to enhance the activity of the photoinitiator package.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If phosphine oxide photoinitiators are used, then deep-cure activity is improved, but surface curing effectiveness deteriorates

Engineering Contradiction:

Improvedeep-cure activityVSAvoidsurface curing effectiveness

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent combines phosphine oxide photoinitiators with coumarin-based sensitizers and amine additives to create a photoinitiator package that merges the deep-cure capabilities of phosphine oxides with the surface-curing enhancement provided by the sensitizer and amine combination, thereby resolving the contradiction between deep-cure activity and surface curing effectiveness

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention creates a composite photoinitiator system comprising multiple components (photoinitiator, sensitizer, and amine additive) that work synergistically to provide both deep-cure and surface-curing properties, transforming the single-component limitation into a multi-component solution

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If Type-I photoinitiators are combined with sensitizers, then energy absorption is improved, but interaction predictability deteriorates

Engineering Contradiction:

Improveenergy absorptionVSAvoidinteraction predictability

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent specifies particular parameter ranges for the coumarin-based sensitizer structure (formula I with specific R1-R8 substituents) and amine additives to standardize the interaction parameters, making the energy transfer process more predictable while maintaining enhanced energy absorption capabilities

Inventive Principle:

Principle #35Parameter changes

3Productivity

If photoinitiator packages are developed to enhance activity, then curing efficiency is improved, but system complexity deteriorates

Engineering Contradiction:

Improvecuring efficiencyVSAvoidsystem complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent assigns specific functional roles to each component in the photoinitiator package: the phosphine oxide provides deep-cure activity, the coumarin-based sensitizer enhances energy absorption and surface curing, and the amine additive further boosts surface curing rate. This localized functional assignment optimizes curing efficiency while maintaining manageable system complexity through clear component differentiation

Inventive Principle:

Principle #3Local quality

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 combination significantly enhances the rate of surface curing in photopolymerizable compositions, particularly when used in photocuring applications such as coatings, adhesives, and inks, and various printing inks.

Implementation Method 1

These compounds absorb light at a different wavelength to that of the photoinitiator itself and transfer energy to the photoinitiator, improving the energy absorption by the photoinitiator

Methodology Applied

Scientific EffectEnergy transfer:

Implementation Method 2

Photoinitiators for promoting the radical polymerisation of ethylenically unsaturated compounds

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 3

Norrish Type-I, wherein an electronically excited photoinitiator fractures to form a free radical that acts to initiate the radical polymerisation

Methodology Applied

Scientific EffectNorrish Type-I fragmentation: Photodissociation

Implementation Method 4

Norrish Type-II, wherein an electronically excited photoinitiator abstracts a hydrogen radical from a further molecule to form a free radical from said further molecule

Methodology Applied

Scientific EffectNorrish Type-II hydrogen abstraction: Photodissociation

Data Source

PatentUS20250304727A1Photoinitiator package comprising phosphine oxide photoinitiators, coumarin-based sensitizers and amine additives

Publication Date: 2025.10.02 IGM GROUP

AI summary

A photoinitiator package comprising one or more mono- or bisacylphosphine oxide photoinitiators, one or more coumarin-based sensitizers and one or more amines, a photopolymerizable composition comprising the photoinitiator package and suitable polymerizable compounds, a method for polymerizing the photopolymerizable composition, a use of the photoinitiator package in photopolymerization applications and a use of a combination of one or more amines and one or more coumarin-based sensitizers for increasing the rate of surface curing in photopolymerizable compositions comprising Norrish Type-I photoinitiators.