Liquid bisacylphosphine oxide photoinitiator

Abstract

A photoinitiator mixture comprising the components (a) a compound of the formula (I) ##STR00001##
wherein Ar.sub.1 and Ar.sub.2 independently of each other are ##STR00002##  or naphthyl which is unsubstituted or substituted one or more times by R.sub.1, R.sub.2, R.sub.3 or R′; R.sub.1 and R.sub.3 in-dependently of each other are C.sub.1-C.sub.4alkyl, C.sub.1-C.sub.4alkoxy or halogen; R.sub.2 is hydrogen, C.sub.1-C.sub.4alkyl, halogen, C.sub.1-C.sub.4alkoxy or C.sub.2-C.sub.20alkoxy which is interrupted by one or more O; Q is C.sub.1-C.sub.4alkylene; R.sub.4 is methyl or ethyl; R′ and R″ independently of each other are hydrogen or PG-Y—R′″—X—; PG is a polymerizable group or methyl or ethyl; Y is a direct bond, O or S; X is a direct bond, O or S; R′″ is a direct bond, C.sub.1-C.sub.20alkylene or C.sub.2-C.sub.20alkylene which is interrupted by one or more O; (b) one or more compounds of the formula (II) ##STR00003##
wherein Ar.sub.1, Ar.sub.2 and Q are as defined above, and R.sub.5 is for example C.sub.3-C.sub.30alkyl which is unsubstituted or substituted and (c) optionally a compound of the formula (III)
R.sub.5—OH  (III),
wherein R.sub.5 is as defined above; provides a liquid photointiator.

Claims

1. A liquid photoinitiator mixture comprising the components (a) a compound of the formula (I) ##STR00028##  wherein Ar.sub.1 and Ar.sub.2 independently of each other are ##STR00029##  or naphthyl which is unsubstituted or substituted one or more times by R.sub.1, R.sub.2, R.sub.3 or R′; R.sub.1 and R.sub.3 independently of each other are C.sub.1-C.sub.4alkyl, C.sub.1-C.sub.4alkoxy or halogen; R.sub.2 is hydrogen, C.sub.1-C.sub.4alkyl, halogen, C.sub.1-C.sub.4alkoxy or C.sub.2-C.sub.20alkoxy which is interrupted by one or more O; Q is C.sub.1-C.sub.4alkylene; R.sub.4 is methyl or ethyl; R′ and R″ independently of each other are hydrogen or PG-Y—R′″—X—; PG is a polymerizable group or methyl or ethyl; Y is a direct bond, O or S; X is a direct bond, O or S; R′″ is a direct bond, C.sub.1-C.sub.20alkylene or C.sub.2-C.sub.20alkylene which is interrupted by one or more O; (b) one or more compounds of the formula (II) ##STR00030##  wherein Ar.sub.1, Ar.sub.2 and Q are as defined above, and R.sub.5 is C.sub.3-C.sub.30alkyl which is unsubstituted or substituted by one or more of the groups selected from OH and ##STR00031## or R.sub.5 is C.sub.2-C.sub.28alkyl which is interrupted by one or more O or C.sub.3-C.sub.8cycloalkylene and which interrupted C.sub.2-C.sub.28alkyl is unsubstituted or substituted by one or more of the groups selected from OH and ##STR00032##  and (c) optionally a compound of the formula (III)
R.sub.5—OH  (III), wherein R.sub.5 is as defined above.

2. The liquid photoinitiator mixture according to claim 1, wherein the mixture comprises 0.1-25% of component (a), 75-99.9% of component (b) and 0-25% of component (c).

3. The liquid photoinitiator mixture according to claim 1, wherein the compounds of the formula (I), (II) and (III) R.sub.1, R.sub.2 and R.sub.3 are C.sub.1-C.sub.4alkyl; R′ and R″ are hydrogen; Q is methylene, and R.sub.5 is C.sub.3-C.sub.30alkyl which is unsubstituted or substituted by ##STR00033##  or R.sub.5 is C.sub.2-C.sub.28alkyl which is interrupted by C.sub.3-C.sub.8cycloalkylene and which interrupted C.sub.3-C.sub.28alkyl is substituted by ##STR00034##

4. The liquid photoinitiator mixture according to claim 1, further comprising a further photoinitiator (C).

5. A photopolymerizable composition comprising (A) at least one monomeric or oligomeric ethylenically unsaturated photopolymerizable compound and (B) at least one liquid photoinitiator mixture according to claim 1.

6. The photopolymerizable composition according to claim 5, which further comprises at least one component selected from the group consisting of a photoinitiator (C) and other customary additives (D).

7. The photopolymerizable composition according to claim 6, wherein the additional photoinitiator (C) is selected from the group consisting of alpha-hydroxy ketones, benzophenone, substituted benzophenone compounds, benzildimethylketal, phenylglyoxylate compounds and alpha-amino ketone compounds.

8. The photopolymerizable composition according to claim 5, comprising 0.05 to 15% by weight of the liquid photoinitiator mixture (B) or the photoinitiators (B)+(C), based on the composition.

9. A process for the photopolymerization of monomeric, oligomeric or polymeric compounds containing at least one ethylenically unsaturated double bond, which comprises adding to the above mentioned compounds a liquid photoinitiator mixture according to claim 1 and irradiating the resulting composition with electromagnetic radiation.

10. A process according to claim 9 for producing coatings, printing inks, printing plates, adhesives, dental compositions, gel coats, photoresists for electronics, for encapsulating electrical and electronic components, for producing magnetic recording materials, for producing micromechanical parts, waveguides, optical switches, plating masks, etch masks, colour proofing systems, glass fibre cable coatings, screen printing stencils, for producing three-dimensional objects by a rapid prototyping or additive manufacturing technology based on a photolithographic or polymer jetting process using light curable materials, for producing image recording material, for holographic recording, for producing microelectronic circuits or for producing decolorizing materials.

11. A coated substrate which is coated on at least one surface with the composition according to claim 5 and irradiated with electromagnetic radiation.

12. A polymerized or crosslinked composition obtained by curing the polymerizable composition according to claim 5.

13. A process for the preparation of the liquid photoinitiator mixture as defined in claim 1, comprising reacting the compound of the formula (I), with an alcohol of the formula (III)
R.sub.5—OH  (III), wherein R.sub.5 is as defined in claim 1, in the presence of a catalyst and taking means to remove the alcohol of the formula (IV) which is formed during the reaction
R.sub.4—OH  (IV), wherein R.sub.4 is methyl or ethyl.

14. The photopolymerizable composition according to claim 5, comprising 0.1 to 5% by weight of the liquid photoinitiator mixture (B) or the photoinitiators (B)+(C), based on the composition.

Description

EXAMPLES

(1) General: The experiments are performed in a round flask with a magnetic stirrer, distillation equipment and vacuum connection. Solvents are used as received. Analysis is performed using .sup.1H- and .sup.31P-NMR spectroscopy and HPLC (Agilent Zorbax XDB Phenyl, 2.1×150 mm/5 μm reversed phase column at 50° C. The eluent gradient is water (75%)/methanol (25%) to 100% methanol over 20 min, followed by 5 min elution using methanol).

Example 1

Preparation of a Liquid Bisacylphosphine Oxide Mixture Using a Large Excess of Alcohol Under Light Vacuum

(2) 3 g (7.2 mmol) [Bis-(2,4,6-trimethyl-benzoyl)-phosphanyl]-acetic acid methyl ester prepared as described in WO06/056541, 40 mg dibutyltin dilaurat and 9.4 g (72 mmol) mixture of octyl alcohols, Exxal 8 (ExxonMobile) are placed in the reaction flask, forming a suspension of the bisacylphosphine oxide in the alcohol. A slight vacuum (280 mbar) is applied and the reaction mixture is heated to 130° C. while stirring. The mixture becomes a clear yellowish solution. The reaction mixture is kept at this temperature for 4 hours while methanol and small amounts of Exxal 8 are distilled off. The progress of the reaction is monitored in regular intervals by HPLC. After 4 hours the ratio methyl ester/octyl ester is >98%. The reaction mixture is cooled to room temperature and the excess alcohol distilled off in high vacuum. An easily pourable yellowish liquid is obtained, which according to .sup.1H-NMR-analysis and HPLC analysis consists of 0.2% bis-(2,4,6-trimethyl-benzoyl)-phosphanyl]-acetic acid methyl ester, 92.4% of the mixture of the corresponding octyl esters (of Exxal 8) and 7.4% Exxal 8. The viscosity of the liquid is 3100 mPas at 23° C.

Example 2

Preparation of a Liquid Bisacylphosphine Oxide Mixture Using a Large Excess of Alcohol Under Higher Vacuum

(3) The reaction as reported in example 1 is repeated except that a vacuum of 100 mbar is applied. Under these conditions, a ratio methyl ester/octyl ester of 96:4 is reached after only one hour at 130° C. After isolation a yellowish liquid containing 88% of the mixture of octyl esters of bis-(2,4,6-trimethyl-benzoyl)-phosphanyl]-acetic acid, 4% bis-(2,4,6-trimethyl-benzoyl)-phosphanyl]-acetic acid methyl ester and 8% Exxal 8 is obtained.

Example 3

Preparation of a Liquid Bisacylphosphine Oxide Mixture Using a Large Excess of Alcohol Under Higher Vacuum and Zr(acac)4 as Catalyst

(4) The reaction as reported in example 2 is repeated except that zirconium(IV)acetyl acetate is used as catalyst instead of dibutyltin dilaurat. Under these conditions, a ratio methyl ester/octyl ester of 96:4 is reached after 4 hours at 130° C. After isolation a yellowish liquid containing 89% of the mixture of octyl esters of bis-(2,4,6-trimethyl-benzoyl)-phosphanyl]-acetic acid, 4% bis-(2,4,6-trimethyl-benzoyl)-phosphanyl]-acetic acid methyl ester and 7% Exxal 8 is obtained.

Example 4

Preparation of a Liquid Bisacylphosphine Oxide Mixture Using a Small Excess of Alcohol Under Higher Vacuum and Zr(acac)4 as Catalyst

(5) 3 g (7.2 mmol) [Bis-(2,4,6-trimethyl-benzoyl)-phosphanyl]-acetic acid methyl ester prepared as described in WO06/056541, 40 mg zirconium(IV)acetyl acetate and 1.4 g (8 mmol) Exxal 8 (ExxonMobile) are placed in the reaction flask. A light vacuum of 100 mbar is applied and the reaction mixture slowly heated to 130° C. The reaction mixture is kept at 130° C. while methanol and small amounts of Exxal 8 are distilled off. The progress of the reaction is monitored in regular intervals by H PLC. After 6.5 hours the ratio methyl ester/octyl ester is 92:8. The reaction mixture is cooled to room temperature. An easily pourable yellowish liquid is obtained without distillation of excess alcohol, which according to .sup.1H-NMR-analysis and HPLC analysis consist of 8% bis-(2,4,6-trimethyl-benzoyl)-phosphanyl]-acetic acid methyl ester, 88% of the mixture of esters corresponding to the Exxal 8 and 4% Exxal 8.

Example 5

Preparation of a Liquid Bisacylphosphine Oxide Mixture Using a Small Excess of Alcohol Under Higher Vacuum and Cyclohexane as Entrainer

(6) 3 g (7.2 mmol) [Bis-(2,4,6-trimethyl-benzoyl)-phosphanyl]-acetic acid methyl ester prepared as described in WO06/056541, 40 mg zirconium(IV)acetyl acetate, 1.4 g (8 mmol) Exxal 8 (ExxonMobile) and 50 ml cyclohexane are placed in the reaction flask forming a turbid suspension. The reaction mixture is slowly heated to 100° C. while stirring without applying vacuum. The reaction mixture becomes a clear yellowish solution. Cyclohexane containing methanol is continuously distilled off and replaced by approximately the same amount of fresh cyclohexane. After 6 hours the ratio methyl ester/octyl ester is 94:6. The reaction mixture is cooled to room temperature. Cyclohexane is distilled off in vacuum providing an easily pourable yellowish liquid, which according to .sup.1H-NMR-analysis and HPLC analysis consist of 5% bis-(2,4,6-trimethyl-benzoyl)-phosphanyl]-acetic acid methyl ester, 92% of the mixture of the esters corresponding to Exxal 8 and 3% Exxal 8.

Example 6

Preparation of a Liquid Bisacylphosphine Oxide Mixture Using a Small Excess of a Mixture of Isomeric Nonanols Under Higher Vacuum and Zr(acac)4 as Catalyst

(7) 622 g (1.5 mol) [bis(2,4,6-trimethylbenzoyl)phosphanyl]acetic acid methyl ester prepared as described in WO06/056541 is added in 5 portions to 238 g (1.65 mol) Nonanol N at 70° C. over 30 min. 1.8 g (0.00375 mol) of zirconium(IV) acetylacetonate is then added and the reaction mixture heated to 95° C. and placed under a vacuum of 60 mbar. Four additional 1.8 g portions zirconium(IV) acetylacetonate are added over the next 4 hours and, subsequently, the reaction mixture is held at 95° C. for a further 2 h. During the course of the reaction, methanol and a small amount of Nonanol N are removed by distillation. At the end of the reaction, a yellow oil is obtained which consists of 87% of isomeric [bis(2,4,6-trimethylbenzoyl)phosphanyl]acetic acid nonyl esters, 8.5% [bis(2,4,6-trimethyl-benzoyl)phosphanyl]acetic acid methyl ester and 4.5% Nonanol N by HPLC analysis.

Example 7

Preparation of a Liquid Bisacylphosphine Oxide Mixture Using 1,6-hexandiol in Toluene and 1,5,7-triazabicyclo[4.4.0]dec-5-ene as Catalyst

(8) 3.03 g (7.3 mmol) [bis(2,4,6-trimethylbenzoyl)phosphanyl]acetic acid methyl ester prepared as described in WO06/056541 and 0.44 g 1,6-hexandiol (3.7 mmol) are suspended in 40 ml toluene. 0.05 g 1,5,7-triazabicyclo[4.4.0]dec-5-ene are added and the mixture is heated to 130° C. Toluene is distilled off during the reaction and continuously replaced by the same amount of solvent. After 8 hours the mixture is cooled to room temperature and volatiles are removed in vacuum. 3.25 g of a yellowish oil is obtained which consists according to NMR analysis of 1,6-hexandiol [bis(2,4,6-trimethyl-benzoyl)phosphanyl]acetic acid diester (approximately 55%), 1,6-hexandiol [bis(2,4,6-trimethylbenzoyl)phosphanyl]acetic acid monoester (31%), bis(2,4,6-trimethyl-benzoyl)-phosphanyl]acetic acid methyl ester (8%) and 1,6-hexandiol (6%).

Example 8

Preparation of a Liquid Bisacylphosphine Oxide Mixture Using 1,4-bis(hydroxymethyl)cyclohexane in Cyclohexne and 1,5,7-triazabicycle-[4.4.0]dec-5-ene as Catalyst

(9) 8.29 g (20 mmol) [bis(2,4,6-trimethylbenzoyl)phosphanyl]acetic acid methyl ester prepared as described in WO06/056541 and 0.72 g 1,4-bis(hydroxymethyl)cyclohexane (5 mmol) are suspended in 50 ml cyclohexane. 0.001 g 1,5,7-triazabicyclo[4.4.0]dec-5-ene are added and the mixture is heated to 80° C. Cyclohexane is distilled off during the reaction and continuously replaced by the same amount of solvent. After 9 hours the mixture is cooled to room temperature and volatiles are removed in vacuum. 3.25 g of a yellowish viscous oil is obtained which consists according to NMR analysis of 1,4-bis(hydroxymethyl)cyclohexane [bis(2,4,6-trimethylbenzoyl)phosphanyl]acetic acid di-ester (approximately 65%), 1,4-bis(hydroxymethyl)cyclohexane [bis(2,4,6-trimethyl-benzoyl)phosphanyl]acetic acid monoester (27%), and bis(2,4,6-tri methyl-benzoyl)-phosphanyl]acetic acid methyl ester (8%).

Application Examples

Example A1

Storage Stability

(10) 3 g of the liquid bisacylphosphine oxide photoinitiator obtained according to example 4 are placed under air in a brown flask. The flask is closed by a stopper and stored under exclusion of light using a “heat and freeze” cycle during which the storage temperature is altered in regular intervals (1 day) between room temperature (22-24° C.) and freezer temperature (3° C.). The condition of the liquid is visually evaluated once per week. After 6 months of storage under these conditions, the photoinitiator is still liquid without any formation of solid parts and easily pourable at room temperature.

Example A2

Dissolution in Monomers

(11) The time and conditions for completely dissolving 2% of bisacylphosphine oxide photoinitiators in different monomers is evaluated.

(12) 2% of the bisacylphosphine oxide photoinitiator and 98% of the monomer are placed in a beaker equipped with a magnetic stirring bar and a heating bath. The mixture is visually evaluated and the time and conditions when a clear solution is formed is rated.

(13) TABLE-US-00001 rating dissolved after 1 15 min at room temperature 2 10 min at 40° C. 3 10 min at 50° C. 4 10 min at 60° C. 5 >10 min at 60 C.

(14) The following results are obtained (average of 5 measurements):

(15) TABLE-US-00002 Photoinitiator HDDA TPGDA TMPTA bis(2,4,6-trimethylbenzoyl)-phenyl 2.5 3.8 4.7 phosphine oxide (Irgacure ® 819) bis(2,4,6-trimethyl-benzoyl)-phosphanyl]- 2.1 2.2 2.8 acetic acid methyl ester bisacylphosphine oxide photoinitiator 1 1 1 obtained according to example 4 HDDA = 1,6-hexanediol diacrylate TPGDA = tripropylene glycol diacrylate TMPTA = trimethylolpropane triacrylate

Example A3

Photoinitiator Performance in a White Pigmented Polyester Acrylate Coating

(16) Photocurable white-pigmented polyester acrylate formulations are prepared, comprising 2% of the photoinitiator to be tested. The formulations are applied onto white-coated chipboards in a thickness of 100 □m and cured with a 80 W mercury medium pressure lamp by passing the samples on a belt under the lamp with a belt speed of 5 m/min.

(17) Determined are curing performance via the pendulum hardness (PH) in seconds according to Konig DIN 53157. The higher the PH value, the more reactive is the tested photoinitiator compound. The yellowing of the formulation after curing is determined via colorimetric determination of the b* value according to the Cielab system. The higher the value, the more colored is the cured coating.

(18) The following results are obtained:

(19) TABLE-US-00003 Photoinitiator PH [s] b* bis(2,4,6-trimethylbenzoyl)-phenyl phosphine oxide 161 4.2 (Irgacure ® 819) bis(2,4,6-trimethyl-benzoyl)-phosphanyl]-acetic 161 4.1 acid methyl ester bisacylphosphine oxide photoinitiator obtained 161 3.3 according to example 4

Example A4

Photoinitiator Performance in Different White Pigmented Photocurable Formulations Using Phenyl-1-hydroxycyclohexyl Ketone as Additional Photoinitiator (C)

(20) The following photocurable formulations are prepared:

(21) Formulation 1

(22) TABLE-US-00004 40.0% by wt of a polyester acrylate (Laromer ® PE9074, provided by BASF SE) 34.3% by wt of dipropylene glycol diacrylate (Laromer ® DPGDA, provided by BASF SE) 0.2% by wt of a slip aid (EFKA ® 3030, provided by BASF SE) 0.5% by wt of a wetting aid (EFKA ® 5220, provided by BASF SE) 21.0% by wt of titanium dioxide (Kronos ® 2300, provided by Kronos) 1.0% by wt of the photoinitiator according to example 6 3.0% by wt of phenyl-1-hydroxycyclohexyl ketone (Irgacure ® 184, provided by BASF SE)

(23) Formulation 2

(24) TABLE-US-00005 30.0% by wt of a polymer based on: polyetherpolyol; epoxy resin; acrylic ester (Laromer ® LR8986, provided by BASF SE 22.3% by wt of an amine modified polyetheracrylate (PO77F, provided by BASF) 22.0% by wt of tripropylene glycol diacrylate (TPGDA) 0.2% by wt of a slip aid (EFKA ® 3030, provided by BASF SE) 0.5% by wt of a wetting aid (EFKA ® 5220, provided by BASF SE) 21.0% by wt of titanium dioxide 1.0% by wt of the photoinitiator according to example 6 3.0% by wt of phenyl-1-hydroxycyclohexyl ketone (Irgacure ® 184, provided by BASF SE)

(25) Formulation 3

(26) TABLE-US-00006 58.3% by wt of an amine modified polyetheracrylate (PO94F provided by BASF) 16.0% by wt of a polyester acrylate (Laromer ® PE9079, provided by BASF SE) 0.2% by wt of a slip aid (EFKA ® 3030, provided by BASF SE) 0.5% by wt of a wetting aid (EFKA ® 5220, provided by BASF SE) 21.0% by wt of titanium dioxide 1.0% by wt of the photoinitiator according to example 6 3.0% by wt of phenyl-1-hydroxycyclohexyl ketone (Irgacure ® 184, provided by BASF SE)

(27) Formulation 4

(28) TABLE-US-00007 30.0% by wt of a polymer based on: polyetherpolyol; epoxy resin; acrylic ester (Laromer ® LR8986, provided by BASF SE 22.3% by wt of an amine modified polyetheracrylate (PO77F, provided by VSF) 22.0% by wt of tripropylene glycol diacrylate (TPGDA) 0.2% by wt of a slip aid (EFKA ® 3030, provided by BASF SE) 0.5% by wt of a wetting aid (EFKA ® 5220, provided by BASF SE) 21.0% by wt of titanium dioxide 2.0% by wt of the photoinitiator according to example 6 2.0% by wt of phenyl-1-hydroxycyclohexyl ketone (Irgacure ® 184, provided by BASF SE)

(29) A4.1: Reactivity

(30) The formulation to be tested is applied with a bar coater on white coil with a thickness of 24 μm. Curing of the formulation is achieved by moving the sample on a belt under a UV Hg high pressure lamp (200 W/cm) with a defined speed. The highest speed which can be used to fully cure the formulation is determined (Full cure is determined by finger nail scratching). The results are collected in the following table 1.

(31) A4.2: Yellowing

(32) The formulation to be tested is applied on white coil with a thickness of 100 μm. Curing of the formulation is achieved by moving the sample on a belt under a Hg lamp (200 W/cm) at a belt speed of 5 m/min. The yellowing of the formulation is determined directly after curing, after 1 h, after 72 h and after further irradiation with a TL03 lamp, via colorimetric determination of the b* value according to the Cielab system. The higher the value, the more yellowish is the cured coating. The results are collected in the following table 1.

(33) A4.3: Pendulum Hardness

(34) The formulation to be tested is applied on white coil with a thickness of 100 μm. Curing of the formulation is achieved by moving the sample on a belt under a Hg lamp (200 W/cm) at a belt speed of 5 m/min. The pendulum hardness (PH) in seconds according to Konig DIN 53157 is determined directly after curing and 72h after storing in a temperature-controlled room at 22° C. The higher the PH value, the more reactive is the tested photoinitiator compound. The results are collected in the following table 1.

(35) A4.4: Maximum Curable Film Thickness

(36) The formulations are poured into a lid of a polyethylene cup, so that the wet thickness is about 2 mm and cured with a 200 W gallium-doped mercury medium pressure lamp by passing the samples on a belt under the lamp with a belt speed of 5 m/min. Then the cured layer is removed from the lid and any uncured material is removed with acetone, dried and the thickness of the sample is measured.

(37) Determined is the maximum film thickness curable under these conditions. The results are collected in the following table 1.

(38) TABLE-US-00008 TABLE 1 Formu- Formu- Formu- Formu- Example lation 1 lation 2 lation 3 lation 4 A4.1; reactivity: belt speed [m/min] 20 30 70 45 A4.2: yellowing b* directly after curing 2.2 2.2 2.3 3.2 b* after 1 h 2.1 1.7 2.2 2.7 b* after 72 h 1.9 1.6 2.2 2.6 b* after further irradiation 0.3 −0.3 0.3 −0.2 A4.3: pendulum hardness [s] directly after curing 63 81 34 88 after 72 h 73 80 21 87 A4.4: maximum film thickness 206 281 253 223 cured [μm]

Example A5

Photoinitiator Performance in a Photocurable Blue Coating Formulation Using Phenyl-1-hydroxycyclohexyl Ketone as Additional Photoinitiator (C)

(39) The Following Photocurable Formulations 5a-5c are Prepared:

(40) Basic Blue Coating Formulation:

(41) TABLE-US-00009 20.0 g of trimethylolpropane triacrylate (TMPTA) 40.0 g of an amine modified polyetheracrylate (PO94F provided by BASF) 30.0 g of a polyester acrylate (Laromer ® PE9079, provided by BASF SE) 0.2 g of a slip aid (EFKA ® 3030, provided by BASF SE) 0.8 g of a wetting aid (EFKA ® 7731, provided by BASF SE) 5.0 g of Heliogen Blue 7110F (PB15:4 blue pigment, by BASF SE) 3.0 g of phenyl-1-hydroxycyclohexyl ketone (Irgacure ®184, provided by BASF SE)

(42) To the Basic Formulation the Following Amounts of Photoinitiator are Added:

(43) Formulation 5a: 0.5 g of the photoinitiator according to example 6

(44) Formulation 5b: 1.0 g of the photoinitiator according to example 6

(45) Formulation 5c: 1.5 g of the photoinitiator according to example 6

(46) A5.1: Reactivity

(47) The formulation to be tested is applied on white coil with a thickness of 25 μm. Curing of the formulation is achieved by moving the sample on a belt under a Hg lamp (120 W/cm) followed by a Ga-doped Hg lamp (120 W/cm) with a defined speed. The highest speed which can be used to fully cure the formulation (finger nail test) is determined. The results are collected in the following table 2.

(48) A5.2: Maximum Curable Film Thickness

(49) The formulations are poured into a lid of a polyethylene cup, so that the wet thickness is about 2 mm and cured with a 200 W gallium-doped mercury medium pressure lamp by passing the samples on a belt under the lamp with a belt speed of 5 m/min. Then the cured layer is removed from the lid and any uncured material is removed with acetone, dried and the thickness of the sample is measured.

(50) Determined is the maximum film thickness curable under these conditions. The results are collected in the following table 2.

(51) TABLE-US-00010 TABLE 2 Formulation Formulation Formulation Example 5a 5b 5c A5.1; reactivity by belt 50 70 90 speed [m/min] A5.2: maximum film 175 220 215 thickness cured [μm]

Example A6

Photoinitiator Performance in a Photocurable Yellow Coating Formulation Using Phenyl-1-hydroxycyclohexyl Ketone as Additional Photoinitiator (C)

(52) The Following Photocurable Formulations 6a-6c are Prepared:

(53) Basic Yellow Coating Formulation:

(54) TABLE-US-00011 20.0 g of trimethylolpropane triacrylate (TMPTA) 40.0 g of an amine modified polyetheracrylate (PO94F provided by BASF) 30.0 g of a polyester acrylate (Laromer ® PE9079, provided by BASF SE) 0.2 g of a slip aid (EFKA ® 3030, provided by BASF SE) 0.8 g of a wetting aid (EFKA ® 7731, provided by BASF SE) 5.0 g of Paliotol Yellow L0962HD (PY 138, yellow pigment, by BASF SE) 3.0 g of phenyl-1-hydroxycyclohexyl ketone (Irgacure ®184, provided by BASF SE)

(55) To the Basic Formulation the Following Amounts of Photoinitiator are Added:

(56) Formulation 6a: 0.5 g of the photoinitiator according to example 6

(57) Formulation 6b: 1.0 g of the photoinitiator according to example 6

(58) Formulation 6c: 1.5 g of the photoinitiator according to example 6

(59) A6.1: Reactivity

(60) The reactivity evaluation is performed as described for A5.1. The results are collected in the following table 3.

(61) A6.2: Maximum Curable Film Thickness

(62) Evaluation of the maximum curable film thickness is performed as described for A5.21. The results are collected in the following table 3.

(63) TABLE-US-00012 TABLE 3 Formulation Formulation Formulation Example 6a 6b 6c A6.1; reactivity by belt 50 50 60 speed [m/min] A6.2: maximum film 37 45 45 thickness cured [μm]

Example A7

Photoinitiator Performance in a Photocurable Red Coating Formulation Using phenyl-1-hydroxycyclohexyl Ketone as Additional Photoinitiator (C)

(64) The Following Photocurable Formulations 7a-7c are Prepared:

(65) Basic Red Coating Formulation:

(66) TABLE-US-00013 20.0 g of trimethylolpropane triacrylate (TMPTA) 40.0 g of an amine modified polyetheracrylate (PO94F provided by BASF) 30.0 g of a polyester acrylate (Laromer ® PE9079, provided by BASF SE) 0.2 g of a slip aid (EFKA ® 3030, provided by BASF SE) 0.8 g of a wetting aid (EFKA ® 7731, provided by BASF SE) 5.0 g of Iragazin ® Red L3670HD (PR254, red pigment, provided by BASF) 3.0 g of phenyl-1-hydroxycyclohexyl ketone (Irgacure ® 184, provided by BASF SE)

(67) To the Basic Formulation the Following Amounts of Photoinitiator are Added:

(68) Formulation 7a: 0.5 g of the photoinitiator according to example 6

(69) Formulation 7b: 1.0 g of the photoinitiator according to example 6

(70) Formulation 7c: 1.5 g of the photoinitiator according to example 6

(71) A7.1: Reactivity

(72) The reactivity evaluation is performed as described for A5.1. The results are collected in the following table 4.

(73) A7.2: Maximum Curable Film Thickness

(74) Evaluation of the maximum curable film thickness is performed as described for A5.21. The results are collected in the following table 4.

(75) TABLE-US-00014 TABLE 4 Formulation Formulation Formulation Example 6a 6b 6c A7.1; reactivity by belt 45 50 50 speed [m/min] A7.2: maximum film 45 50 50 thickness cured [μm]

Example A8

Curing Performance of the Photoinitiator According to Example 6 Alone and in Combination with phenyl-1-hydroxycyclohexyl Ketone as Additional Photoinitiator (C) in a White Pigmented Photocurable Formulation

(76) The Following Photocurable Formulations 8a-8b are Prepared:

(77) Basic White Coating Formulation

(78) TABLE-US-00015 15.0 g of trimethylolpropane triacrylate (TMPTA) 35.3 g of an amine modified polyetheracrylate (PO94F provided by BASF) 20.0 g of a polyester acrylate (Laromer ® PE9079, provided by BASF SE) 0.2 g of a slip aid (EFKA ® 3030, provided by BASF SE) 0.8 g of a wetting aid (EFKA ® 5220, provided by BASF SE) 25.0 g of titanium dioxide (TiO.sub.2 CL 2310)

(79) To the Basic Formulation the Following Amounts of Photoinitiator are Added:

(80) Formulation 8a: 1.0 g of the photoinitiator according to example 6 and 3.0 g phenyl-1-hydroxycyclohexyl ketone (Irgacure®184, provided by BASF) as additional photoinitiator (C)

(81) Formulation 8b: 4.0 g of the photoinitiator according to example 6

(82) A8.1: Reactivity

(83) The reactivity evaluation is performed as described for A5.1. The results are collected in the following table 5.

(84) A8.2: Maximum Curable Film Thickness

(85) Evaluation of the maximum curable film thickness is performed as described for A5.2. The results are collected in the following table 5.

(86) A8.3 Storage Stability

(87) In order to check the storage stability of the ready-to-use formulations 8a and 8b, the two formulations are stored at 40° c for 3 months. After this time the evaluation tests A8.1 and A8.2 are repeated. The results are collected in the following table 5.

(88) TABLE-US-00016 TABLE 5 Example Formulation 8a Formulation 8b A7.1; reactivity by belt speed 70 30 [m/min] after 3 months storage at 40° C. 70 35 A7.2: maximum film 210 175 thickness cured [μm] after 3 months storage at 40° C. 210 165

Example A9

Curing Performance of the of the Photoinitiator According to Example 6 in Combination with Different Additional Photoinitiators (C) in a White Pigmented Photocurable Formulation

(89) The Following Photocurable Formulations 9a-9e are Prepared:

(90) Basic White Coating Formulation

(91) TABLE-US-00017 80.3% by wt of an epoxy acrylate (Laromer ® LR898/6, provided by BASF SE) 0.2% by wt of a slip aid (EFKA ® 3030, provided by BASF SE) 0.5% by wt of a wetting aid (EFKA ® 5220, provided by BASF SE) 15.0% by wt of titanium dioxide (TiO.sub.2 CL 2310)

(92) To the Basic Formulation the Following Amounts of Photoinitiator are Added:

(93) Formulation 9a: 1.0% by wt of the photoinitiator according to example 6 and 3.0% by wt of a difunctional α-hydroxy ketone (Esacure® ONE, provided by Lamberti Spa) as additional photoinitiator (C)

(94) Formulation 9b: 1.0% by wt of the photoinitiator according to example 6 and 3.0% by wt of 2-hydroxy-2-methyl-1-phenyl-propanone (Darocur0 1173, provided by BASF SE) as additional photoinitiator (C)

(95) Formulation 9c: 1.0% by wt of the photoinitiator according to example 6 and 3.0% by wt of phenyl-1-hydroxycyclohexyl ketone (Irgacure® 184, provided by BASF SE) as additional photoinitiator (C)

(96) Formulation 9d: 1.0% by wt of the photoinitiator according to example 6 and 3.0% by wt of methyl α-oxo benzeneacetate (Darocur® MBF, provided by BASF SE) as additional photoinitiator (C)

(97) Formulation 9e: 1.0% by wt of the photoinitiator according to example 6 and 3.0% by wt of 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one (Irgacure® 127, provided by BASF SE) as additional photoinitiator (C)

(98) A9.1: Reactivity

(99) The formulation to be tested is applied on white coil with a wet thickness of 100 μm. Curing of the formulation is achieved by moving the sample on a belt under a Hg lamp (200 W/cm) with a defined speed. The highest speed which can be used to fully cure the formulation is determined by finger nail scratch. The results are collected in the following table 6.

(100) A9.2: Pendulum Hardness

(101) The formulation to be tested is applied on white coil with a thickness of 100 μm. Curing of the formulation is achieved by moving the sample on a belt under a Hg lamp (120 W/cm) at a belt speed of 5 m/min. The pendulum hardness (PH) in seconds according to Konig DIN 53157 is determined after >24h storing in a temperature-controlled room at 22° C. The higher the PH value, the more reactive is the tested photoinitiator compound. The results are collected in the following table 6.

(102) TABLE-US-00018 TABLE 6 Formu- Formu- Formu- Formu- Formu- lation lation lation lation lation Example 9a 9b 9c 9d 9e A9.1; reactivity 35 42.5 30 60 40 by belt speed [m/min] A9.2: pendulum 86 73 76 59 76 hardness [s]

Example A10

Curing Performance of the of the Photoinitiator According to Example 6 in a Photocurable Water-Borne Clear and White Formulations

(103) Water-borne clear Formulations 10a-10b are prepared by mixing:

(104) Formulation 10a:

(105) TABLE-US-00019 100.0 g of a water-based urethane acrylate dispersion (Laromer ® WA 9057, provided by BASF SE) 0.5 g of a rheology modifier (DSX 1550 5% in water, provided by BASF SE) 1.0 g of the photoinitiator according to example 6

(106) Formulation 10b:

(107) TABLE-US-00020 100.0 g of a water-emulsifiable polyester acrylate (Laromer ® PE 22 WN, provided by BASF SE) 0.5 g of a rheology modifier (DSX 1550 5% in water, provided by BASF SE) 1.0 g of the photoinitiator according to example 6

(108) Water-Borne White Formulations 10c-10d are Prepared by Mixing:

(109) Formulation 10c:

(110) TABLE-US-00021 100.0 g of a water-based urethane acrylate dispersion (Laromer ® WA 9057, provided by BASF SE) 0.5 g of a rheology modifier (DSX 1550 5% in water, provided by BASF SE) 12.7 g of an aqueous titanium dioxide pigment dispersion (Luconyl ® NG white 0022, provided by BASF SE) 1.0 g of the photoinitiator according to example 6 1.2 g of a photoinitiator blend of phenyl-1-hydroxycyclohexyl ketone and benzophenone in the ratio 1:1 (Irgacure ® 500, provided by BASF SE)

(111) Formulation 10d:

(112) TABLE-US-00022 100.0 g of a water-emulsifiable polyester acrylate (Laromer ® PE 22 WN, provided by BASF SE) 0.5 g of a rheology modifier (DSX 1550 5% in water, provided by BASF SE) 12.7 g of an aqueous titanium dioxide pigment dispersion (Luconyl ® NG white 0022, provided by BASF SE) 1.0 g of the photoinitiator according to example 6 1.2 g of a photoinitiator blend of phenyl-1-hydroxycyclohexyl ketone and benzophenone in the ratio 1:1 (Irgacure ® 500, provided by BASF SE)

(113) A10.1: Reactivity

(114) The formulation to be tested is applied on white aluminium coil panels with a wet thickness of 100 μm. The panels are then dried at 50° C. for 10 min. Curing of the formulation is achieved by moving the sample on a belt under two Hg lamp (120 W/cm) with at a belt speed of 5 m/min. Reactivity (through cure) is measured by the pendulum hardness (PH) in seconds according to König DIN 53157, determined after storing over night at room temperature. The higher the PH value, the more reactive is the tested photoinitiator compound.

(115) Alternatively cure is also measured using the acetone double rub test, where an acetone soaked cotton ball is rubbed until the coating is removed. The higher the number of double rubs before the coating is removed, the better the curing efficiency of the photoinitiator.

(116) The results are collected in the following table 7.

(117) TABLE-US-00023 TABLE 7 Formu- Formu- Formu- Formu- lation 11a lation 11b lation 11c lation 11d Example clear clear white white A10.1: reactivity; pendu- — — 71 84 lum hardness [s] A10.2: reactivity; acetone double rubs after curing >200 >200 99 >200 after 3 days >200 >200 >200 >200

Example A11

Curing Performance of the of the Photoinitiator According to Example 3 in a Photocurable Water-Borne White Pigmented Formulation

(118) A Water-Borne White Pigment Paste is Prepared by Mixing of the Following Ingredients:

(119) TABLE-US-00024 48.2% by wt of water 6.0% by wt of a wetting and dispersing additive (Disperbyk ® 190, provided by BYK) 1.0% by wt of a defoamer (Dehydran ® 1620, provided by BYK) 0.8% by wt of a hydrophilic fumed silica (Aerosil ® 200, provided by Evonik), 150.0% by wt of a titanium dioxide white pigment for waterborne systems (Kronos ® 2310, provided by Kronos)

(120) This Pigment Paste is Used for the Preparation of the Following Water-Borne White Lacquer:

(121) TABLE-US-00025 256.0% by wt of a water-borne UV curable polyurethane dispersion (Bayhydrol ® UV XP 2629, provided by Bayer) 40.0% by wt of butylglycol/water 1:1 2.4% by wt of a defoamer (BYK ® 024, provided by BYK) 4.0% by wt a surfactant (BYK ® 346, provided by BYK) 0.8% by wt a surface additive (BYK ® 332, provided by BYK) 176.0% by wt of the white pigment paste as described above 52.8% by wt of water 1.0% by wt of the photoinitiator according to example 3

(122) The following tests are undergone with samples of the formulation (a) directly after the preparation of the formulation (b) after 4 weeks of storing the formulation and (c) after 12 weeks of storing the formulation.

(123) A11.1: Reactivity

(124) The formulation to be tested is applied on white pre-coated aluminum panels coil with a wet thickness of 100 μm. The panels are then dried at 50° C. for 10 min. Curing of the formulation is achieved by moving the sample on a belt under two Hg lamp (100 W/cm) with at a belt speed of 10 m/min. The pendulum hardness (PH) in seconds according to Konig DIN 53157 is determined The higher the PH value, the more reactive is the tested photoinitiator compound. The results are collected in table 8.

(125) A11.2: Gloss

(126) The samples are prepared and cured as described in A10.1

(127) Gloss is measured at 20°. The results are collected in the following table 8.

(128) TABLE-US-00026 TABLE 8 Example A10.1: pendulum hardness [s] immediately after preparation 165 after 4 weeks storage 185 after 12 weeks storage 170 Example A11.2: Gloss (GLU) immediately after preparation 52 after 4 weeks storage 78 after 12 weeks storage 81