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Photoinitiators for Low Migration Applications

Leading the wayWhat is Migration?

Substrate

Ink

Substrate

Ink

Substrate

Ink

Penetration Migration Contact/ Set off migration

Substrate

Ink

Evaporation Migration

Substrate

Ink

Condensation Migration

Leading the wayUV Energy Curing Formulation

Resins and Oligomers

Monomers and Diluents

Photoinitiators

Additives

100% solids formulation

Low migration potential: High acrylate functionality and molecular weight.

High migration potential:Low acrylate functionality and molecular weight.

Small molecules will readily migrate. Low migration photoinitiators can be used.

Many additives will readily migrate.Specialist low migration options may be available.

Leading the wayMigration from Photoinitiators

O

R R

CH3N(R)

2

OH

CH2N(R)

2

. .

Aryl aryl ketone Amine synergist Ketyl radicalinert

Alkylamino radicalreactive

O

OH

R

O

OH. .

Aryl alkyl ketone Benzoyl radical Alkyl radical

Type I photoinitiators

Type II photoinitiators

Fragments cause potential migration issues in some applications.

Unreacted species cause potential migration issues in some applications.

Leading the wayRegulation Around Migration

Originally regulation imposed by industries on food packaging applications. • EuPIA regulation (November 2016). • Nestle List (Version 4.0.1. 2016) • Swiss Ordinance (Annex 10, RS817.023.12)• EU No 10/2011

Regulation on migration in non-food applications. IKEA (IOS-MAT-0066)

Standard photoinitiators can be used as long as migration levels are below the threshold values and excluded products are not used. Polymeric photoinitiators provide an

alternative with lower migration risk.

Leading the wayMolecular Weight and Migration

0

10

20

30

40

50

60

70

80

90

250 500 750 1000

Mig

ration

Molecular Weight / g mol-1

Low

High

Low Molecular WeightPhotoinitiators SpeedCure 73, 84, BP, ITXhave MWs of 250 g mol-1 or less and are known to readily migrate.

High Molecular WeightPhotoinitiators with MW around 500 g mol-1

give low migration.Those with MW of 1000 g mol-1 give near-zero migration.

Green, W. Arthur. Industrial Photoinitiators: A Technical Guide. CRC Press, 2010.

Leading the wayPolymeric Photoinitiators

PI

PI

PI

PI

PI

PI

Features:High molecular weight Low volatilityLow odourHigh viscosity Affects rheology.Reactivity Depends on mole fraction PI.

High molecular weight structures have been designed to reduce migration

Leading the wayPolymeric Photoinitiator Products

7005

• Liquid polymeric benzophenone.• Molecular weight (Mn) ~ 1200 g mol-1. • Very low migration and low odour.• Used in combination with a polymeric amine

synergist. 0

0.5

1

1.5

2

2.5

3

3.5

210 260 310 360 410

Ab

sorb

ance

Wavelength (nm)

Leading the way

• Highly active multifunctional polymeric thioxanthone• Mercury and LED active• Molecular weight (Mn) ~ 1800 g mol-1. • Very low migration and low yellowing• Used with a polymeric amine synergist

0

0.5

1

1.5

2

2.5

3

210 260 310 360 410

Ab

sorb

ance

Wavelength (nm)

7010

Polymeric Photoinitiator Products

Leading the wayPolymeric photoinitiator Products

• Liquid polymeric amine.• Molecular weight (Mn) ~1050 g mol-1.• Highly efficient polymeric amine synergist.• Very low migration and low odour.

0

0.5

1

1.5

2

2.5

3

210 260 310 360 410

Ab

sorb

ance

Wavelength (nm)

7040

Leading the wayPolymeric Photoinitiator Products

• Liquid polymeric thioxanthone in EO-TMPTA.• Designed for low migration inks and coatings (mercury & LED active)• Used in combination with polymeric amine synergist

• Low migration ready to use formulated PI (mercury & LED active)• Designed for food packaging related applications of UV

Flexographic, Offset and Screen Printing inks where low migration as a main characteristic is mandatory.

LM

7010-L

01

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