Photoinitiator Blend With Optical Brighteners for Surface Curing

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Solution Overview

Problem

Phosphine oxide photoinitiators are less effective in achieving surface curing, and the interaction of different Type-I photoinitiators with sensitizers is unpredictable, limiting their broad application in photopolymerization processes.

Innovation Solution

A photoinitiator package comprising bisacylphosphine oxide and further acylphosphine oxide photoinitiators, along with optical brightener sensitizers, forming a liquid blend at 25°C and standard pressure, enhances photopolymerization by improving surface curing abilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

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

Engineering Contradiction:

Improvedeep-cure activityVSAvoidsurface curing ability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent combines phosphine oxide photoinitiators with other photoinitiator types (such as Type-II photoinitiators or different Type-I photoinitiators) to create a photoinitiator package that delivers both deep-cure activity from the phosphine oxide component and surface curing ability from the complementary photoinitiator component

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention uses composite photoinitiator systems where multiple photoinitiator compounds are blended together, each contributing different functional properties - the phosphine oxide provides deep penetration and the complementary photoinitiator provides surface curing, creating a composite system with superior overall performance

Inventive Principle:

Principle #40Composite materials

2Productivity

If new Type-I photoinitiators are developed, then photopolymerization activity is improved, but prediction of sensitizer interaction becomes more difficult

Engineering Contradiction:

Improvephotopolymerization activityVSAvoidsensitizer interaction predictability

Core Design Contradiction:

ProductivityVSDifficulty of detecting and measuring

Solution Approach 1:

The patent modifies molecular parameters of photoinitiators (such as substituent groups on the phosphine oxide structure) to tune photophysical properties like absorption wavelength and energy levels, thereby improving activity while systematically understanding sensitizer interactions through controlled parameter variation

Inventive Principle:

Principle #35Parameter changes

3Productivity

If photoinitiator packages are created to enhance activity, then photopolymerization performance is improved, but formulation complexity increases

Engineering Contradiction:

Improvephotopolymerization performanceVSAvoidformulation complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent develops photoinitiator packages where the combination of components provides multiple functions simultaneously - enhanced deep-cure activity, improved surface curing, and broadened spectral sensitivity - allowing a single package formulation to perform multiple roles that would otherwise require separate additive components

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

The combination of bisacylphosphine oxide and acylphosphine oxide photoinitiators with optical brightener sensitizers results in unexpectedly excellent photoinitiator properties, including enhanced surface curing capabilities.

Implementation Method 1

Photoinitiators for promoting the radical polymerisation of ethylenically unsaturated compounds

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

an electronically excited photoinitiator fractures to form a free radical that acts to initiate the radical polymerisation

Methodology Applied

Scientific EffectPhotoinitiation:

Implementation Method 3

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 4

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 EffectHydrogen abstraction:

Data Source

PatentEP4534614B1Photoinitiator package comprising specialised bisacylphosphine oxide photoinitiators, further acylphosphine oxide photoinitiators and optical brightener sensitizers

Publication Date: 2026.04.15 IGM GROUP

AI summary

A photoinitiator package comprising one or more bisacylphosphine oxide photoinitiators, one or more further acylphosphine oxide photoinitiators and one or more optical brightener sensitizers, a photopolymerizable composition comprising the photoinitiator package and suitable polymerizable compounds, a method for polymerizing the photopolymerizable composition and a use of the photoinitiator package in photopolymerization applications.