Hybrid photoinitiators

Abstract

Compounds of the formula I ##STR00001##
wherein m is 1 or 2; R.sub.1, R.sub.2, R.sub.4 and R.sub.5 independently of one another are hydrogen, C.sub.1-C.sub.4alkyl, C.sub.5-C.sub.7 cycloalkyl, phenyl, C.sub.1-C.sub.4alkoxy, C.sub.5-C.sub.7cycloalkoxy or phenoxy; R.sub.3, if m is 1, has one of the meanings as given above for R.sub.1, R.sub.2, R.sub.4 and R.sub.5; R.sub.3, if m is 2, is a divalent group; R.sub.6 is hydrogen or C.sub.1-C.sub.4alkyl; R.sub.7 is hydrogen, and if R.sub.6 is hydrogen then R.sub.7 may additionally be C.sub.1-C.sub.4alkyl; R.sub.8 is group A or B ##STR00002## X is O, OCH.sub.2 or O(CHR.sub.14); n is 0-10; provided that (i) if n is 0, and X is O, then R.sub.8 is a group A; (ii) if n is other than 0, then X is O and R.sub.8 is the group A; R.sub.9 and R.sub.10 independently of one another are hydrogen or C.sub.1-C.sub.4alkyl; R.sub.11 and R.sub.12 independently of one another are C.sub.1-C.sub.4alkyl or form together with the C atom to which they are attached a 5 to 7 membered saturated carbocyclic ring; R.sub.13 is hydrogen, C.sub.1-C.sub.4alkyl, C.sub.5-C.sub.7cycloalkyl, 2-tetrahydropyranyl or Si(C.sub.1-C.sub.4alkyl).sub.3; R.sub.14 is a group A ##STR00003##
and R.sub.13 has one of the meanings as given for R.sub.13 or is the group C ##STR00004##
are effective photoinitiator compounds.

Claims

1. A compound of the formula I ##STR00029## m is 1 or 2; R.sub.1, R.sub.2, R.sub.4 and R.sub.5 independently of one another are hydrogen, C.sub.1-C.sub.4alkyl, C.sub.5-C.sub.7cycloalkyl, phenyl, C.sub.1-C.sub.4alkoxy, C.sub.5-C.sub.7cycloalkoxy or phenoxy; R.sub.3, if m is 1 has one of the meanings as given above for R.sub.1, R.sub.2, R.sub.4 and R.sub.5; R.sub.3, if m is 2 is a divalent group; R.sub.6 is hydrogen or C.sub.1-C.sub.4alkyl; R.sub.7 is hydrogen, and if R.sub.6 is hydrogen then R.sub.7 may additionally be C.sub.1-C.sub.4alkyl; R.sub.8 is group A or B ##STR00030## X is O, OCH.sub.2 or O(CHR.sub.14); n is 0-10; provided that (i) if n is 0, and X is O, then R.sub.8 is a group A, (ii) if n is other than 0, then X is O and R.sub.8 is the group A, R.sub.9 and R.sub.10 independently of one another are hydrogen or C.sub.1-C.sub.4alkyl; R.sub.11 and R.sub.12 independently of one another are C.sub.1-C.sub.4alkyl or form together with the C atom to which they are attached a 5 to 7 membered saturated carbocyclic ring; R.sub.13 is hydrogen, C.sub.1-C.sub.4alkyl, C.sub.5-C.sub.7cycloalkyl, 2-tetrahydropyranyl or Si(C.sub.1-C.sub.4alkyl).sub.3; ##STR00031## and R.sub.14 is a group A R.sub.13 has one of the meanings as given for R.sub.13 or is the group C ##STR00032##

2. The compound according to claim 1, wherein m is 1.

3. The compound according to claim 1, wherein m is 1; R.sub.1, R.sub.2, R.sub.4 and R.sub.5 are hydrogen; R.sub.3 has one of the meanings as given above for R.sub.1, R.sub.2, R.sub.4 and R.sub.5; R.sub.6 is hydrogen or C.sub.1-C.sub.4alkyl; R.sub.7 is hydrogen; R.sub.8 is group A or B X is O, OCH.sub.2 or O(CHR.sub.14); n is 0 or 1; provided that (i) if n is 0, and X is O, then R.sub.8 is a group A, (ii) if n is other than 0, then X is O and R.sub.8 is the group A, R.sub.9 and R.sub.10 are hydrogen or C.sub.1-C.sub.4alkyl; R.sub.11 and R.sub.12 are C.sub.1-C.sub.4alkyl; R.sub.13 is hydrogen; R.sub.14 is a group A and R.sub.13 has one of the meanings as given for R.sub.13 or is the group C ##STR00033##

4. A photopolymerizable composition comprising (A) at least one ethylenically unsaturated photopolymerizable compound and (B) at least one photoinitiator compound of the formula I according to claim 1.

5. The photopolymerizable composition according to claim 4, which additionally to the component (B) comprises at least one further photoinitiator (C), or further additives (D), or at least one further photoinitiator (C) and further additives (D).

6. The polymerizable composition according to claim 4, which comprises 0.05 to 15% by weight of the at least one photoinitiator compound based on the total composition.

7. The polymerizable composition according to claim 4, which comprises 0.1 to 10% by weight of the at least one photoinitiator compound based on the total composition.

8. A process for the photopolymerization of monomeric, oligomeric or polymeric compounds containing at least one ethylenically unsaturated double bond, which comprises adding to the monomeric, oligomeric or polymeric compounds at least one photoinitiator compound of the formula I according to claim 1 and irradiating the resulting composition with electromagnetic or particulate radiation.

9. A process which comprises utilizing the photopolymerizable polymerizable composition according to claim 4 wherein the process is for the preparation of pigmented and nonpigmented paints and varnishes, powder coatings, printing inks, adhesives, sealings, potting components, dental compositions, foams, moulding compounds, composite compositions, glass fibre cable coatings, screen printing stencils, for producing three-dimensional objects by means of stereolithography, and as image recording material, photoresist compositions, decolorizing materials, decolorizing materials for image recording materials, and for image recording materials using microcapsules.

10. The process according to claim 9 wherein the process is for the preparation of pigmented and nonpigmented paints and varnishes, powder coatings, screen printing inks, inks for offset-, flexo- or inkjet printing, printing plates, adhesives, sealings, potting components, dental compositions, foams, moulding compounds, composite compositions, glass fibre cable coatings, screen printing stencils, for producing three-dimensional objects by means of stereolithography, and as image recording material, photoresist compositions, decolorizing materials, decolorizing materials for image recording materials, and for image recording materials using microcapsules.

11. A coated substrate coated on at least one surface with the composition according to claim 4.

12. A polymerized or crosslinked composition obtained by curing the polymerizable composition according to claim 4.

13. A process for the preparation of the compound of the formula I as defined in claim 1, which comprises acylating a OH functionalized -hydroxyketone of the formula III ##STR00034## wherein X is O, OCH.sub.2 or O(CHR.sub.14); n is 0-10; R.sub.6 is hydrogen or C.sub.1-C.sub.4alkyl; R.sub.7 is hydrogen, and if R.sub.6 is hydrogen then R.sub.7 may additionally be C.sub.1-C.sub.4alkyl; with phenyl glyoxylic acid or a derivative of a phenyl glyoxylic acid of the formula IVa or IVb ##STR00035## R.sub.8 is group A or B ##STR00036## R.sub.9 and R.sub.1 independently of one another are hydrogen or C.sub.1-C.sub.4alkyl; R.sub.11 and R.sub.12 independently of one another are C.sub.1-C.sub.4alkyl or form together with the C atom to which they are attached a 5 to 7 membered saturated carbocyclic ring; R.sub.13 is hydrogen, C.sub.1-C.sub.4alkyl, C.sub.5-C.sub.7cycloalkyl, 2-tetrahydropyranyl or Si(C.sub.1-C.sub.4alkyl).sub.3; ##STR00037## R.sub.14 is a group A R.sub.13 has one of the meanings as given for R.sub.13 or is the group C ##STR00038## wherein R.sub.1, R.sub.2, R.sub.4 and R.sub.5 independently of one another are hydrogen, C.sub.1-C.sub.4alkyl, C.sub.5-C.sub.7cycloalkyl, phenyl, C.sub.1-C.sub.4alkoxy, C.sub.5-C.sub.7cycloalkoxy or phenoxy; R.sub.3, if m is 1 has one of the meanings as given above for R.sub.1, R.sub.2, R.sub.4 and R.sub.5; R.sub.3, if m is 2 is a divalent group; and Y is a OH, Cl or Br, optionally in the presence of a base.

Description

EXAMPLE 1

2-[4-(2-Hydroxy-2-methyl-propanoyl)phenoxy]ethyl 2-oxo-2-phenyl-acetate

(1) ##STR00022##

(2) Acylation of -hydroxyketone with chloride of phenyl glyoxylic acid. 2-Hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-propan-1-one (Irgacure 2959, BASF) (3.36 g, 15 mmol) and 4-dimethylaminopyridine (0.1 g) are dissolved in 30 ml of dry pyridine. To this solution is added at 5-10 C. the solution of 2-oxo-2-phenyl-acetyl chloride (2.48 g, 15 mmol) in 30 ml dichloromethane and the resulting mixture is stirred for 1 h at room temperature. It is then diluted with 300 ml of water, and the organic layer is separated. The aqueous phase is extracted with 50 ml of dichloromethane. The combined organic phases are washed with 350 ml 2M-HCl and 30 ml 1M-NaHCO.sub.3, then dried over MgSO.sub.4 and evaporated. The residue is chromatographed on 130 g silica gel with hexane-ethyl acetate to afford 4.08 g of the title compound as thick oil solidifying on standing. Recrystallization from hexane-dichloromethane affords the analytically pure sample as white crystals, mp. 52-54 C.

(3) .sup.1H-NMR (CDCl.sub.3, 400 MHz, ppm): 8.08 (d, 2H), 8.04 (d, 2H), 7.68 (t, 1H), 7.54-7.50 (m, 2H), 6.98 (d, 2H), 4.81-4.79 (m, 2H, CH.sub.2), 4.42-4.40 (m, 2H, CH.sub.2), 4.20 (s, 1H, OH), 1.63 (s, 6H, 2CH.sub.3).

(4) .sup.13C-NMR (CDCl.sub.3, 100.62 MHz, ppm): 202.59, 185.80, 163.51, 161.92, 135.12, 132.46, 132.26, 130.05, 128.96, 126.68, 114.17, 76.00, 65.56, 63.76, 28.63.

EXAMPLE 2

Bis[4-(2-hydroxy-2-methyl-propanoyl)phenyl]methyl 2-oxo-2-phenyl-acetate

(5) ##STR00023##

(6) A solution of 2-oxo-2-phenyl-acetyl chloride (12 g, 71 mmol), and 1,1-[(hydroxymethylene)di-4,1-phenylene]bis[2-hydroxy-2-methyl-1-propanone, (21 g, 59 mmol; prepared according to example 6 of patent application WO2004/099262) in 40 ml tetrahydrofuran is cooled to 0 C. in an ice bath. Triethylamine (9 g, 89 mmol) is added dropwise over 45 min under stirring at 0 C. and 5 C. After 1.5 h, the temperature is allowed to rise to 25 C. overnight. The reaction mixture is poured onto iced water, extracted with ethyl acetate; the organic phases are washed with water to pH 6 and rotary evaporated. The residue is chromatographed on silicagel with dichloromethane:ethyl acetate 9:1 to give two main products. The more polar is compound 2, 14.0 g (49%), obtained as a yellow, viscous oil.

(7) .sup.1H-NMR (CDCl.sub.3, 400 MHz, ppm): 8.06 (d, 4H), 7.95 (d, 2H), 7.66 (t, 1H), 7.48-7.53 (m, 6H), 7.18 (s, 1H), 3.88 (bs, 2 OH), 1.61 (s, 12H).

EXAMPLE 3

[[4-(2-Hydroxy-2-methyl-propanoyl)phenyl]-[4-[2-methyl-2-(2-oxo-2-phenyl-acetyl)oxy-propanoyl]phenyl]methyl] 2-oxo-2-phenyl-acetate

(8) ##STR00024##

(9) This compound is isolated by column chromatography as the less polar product after the experiment of example 2. Yellow viscous oil, 9.0 g (24%).

(10) .sup.1H-NMR (CDCl.sub.3, 400 MHz, ppm): 8.13 (d, 2H), 8.07 (d, 2H), 7.94 (d, 2H), 7.64-7.70 (m, 3H), 7.47-7.58 (m, 7H), 7.36 (t, 2H), 7.17 (s, 1H), 3.86 (s, 1 OH), 1.89 (s, 6H), 1.63 (s, 6H).

EXAMPLE 4

[4-(2-hydroxy-2-methyl-propanoyl)phenyl]methyl 2-oxo-2-phenyl-acetate

(11) ##STR00025##

(12) The product of example 4 is prepared from 2-hydroxy-1-[4-(hydroxymethyl)phenyl]-2-methyl-1-propanone, (obtained according to EP 1763499) by reaction with 2-oxo-2-phenyl-acetyl chloride as described in Example 1. Yellow oil after chromatography.

(13) .sup.1H-NMR (CDCl3, 300 MHz, ppm): 8.10-7.40 (m, 9ArH), 5.18 (s, 2H, CH.sub.2), 4.02 (s, 1H, OH), 1.61 (s, 6H, 2CH.sub.3).

EXAMPLE 5

[3-(2-hydroxy-2-methyl-propanoyl)phenyl]methyl 2-oxo-2-phenyl-acetate

(14) ##STR00026##

(15) The title compound is prepared in analogy to Example 4 from 2-hydroxy-1-[3-(hydroxymethyl)phenyl]-2-methyl-propan-1-one (prepared as described by Zhang, Yongbo; Wang, Yanchao; Wang, Yapeng; Song, Huaihai; Wang, Zhigang, in WO 2012062041A1, CAN 156:638512, AN 2012:705188) and 2-oxo-2-phenyl-acetyl chloride. Slightly yellow oil,

(16) .sup.1H-NMR (CDCl.sub.3, 400 MHz, ppm): 8.10-7.40 (m, 9 ArH), 5.10 (s, 2H, CH.sub.2), 4.0 (s, 1H, OH), 1.63 (s, 6H, 2CH.sub.3).

EXAMPLE 6

2-[4-(2-hydroxy-2-methyl-propanoyl)-2,6-dimethyl-phenoxy]ethyl 2-oxo-2-phenyl-acetate

(17) ##STR00027##

(18) The title compound is prepared in analogy to Example 1 from 2-hydroxy-1-[4-(2-hydroxyethoxy)-3,5-dimethylphenyl]-2-methyl-1-propanone (prepared as described by Nakamura, Masaki, JP 2009143972A, CAN 151:111890, AN 2009:790996) and 2-oxo-2-phenyl-acetyl chloride. Slightly yellow oil,

(19) .sup.1H-NMR (CDCl.sub.3, 400 MHz, ppm): 8.10-7.40 (m, 7 ArH), 4.7 (m, 2H, CH.sub.2), 4.3 (m, 2H, CH.sub.2), 4.1 (s, 1H, OH), 2.4 (s, 2CH.sub.3), 1.63 (s, 6H, 2CH.sub.3).

EXAMPLE 7

[2-[4-(2-hydroxy-2-methyl-propanoyl)phenoxy]-1-methyl-ethyl] 2-oxo-2-phenyl-acetate

(20) ##STR00028##

(21) The key intermediate for the title is 2-hydroxy-1-[4-(2-hydroxypropoxy)phenyl]-2-methyl-propan-1-one which is synthesized from 1-phenoxypropan-2-ol in analogy to the synthesis of Irgacure 2959 as described by Koehler, Manfred; Ohngemach, Joerg; Wehner, Gregor; Gehlhaus, Juergen, WO 8605778A1 (1986). White solid, mp 75-76 C.,

(22) .sup.1H-NMR (CDCl.sub.3, 400 MHz, ppm): 8.05 (d, 2 ArH), 6.95 (d, 2 ArH), 4.35 (m, 1H), 4.25 (bs, OH), 4.05-3.90 (m, CH.sub.2), 2.45 (s, OH), 1.64 (s, 2CH.sub.3), 1.30 (d, CH.sub.3).

(23) This intermediate is esterified with 2-oxo-2-phenyl-acetyl chloride as described in Example 1. The product is isolated as a thick, slightly yellow oil.

(24) .sup.1H-NMR (CDCl.sub.3, 400 MHz, ppm): 8.15-7.00 (m, 9 ArH), 5.70 (m, 1H), 4.25 (m, CH2), 4.20 (bs, OH), 1.70 (s, 2CH.sub.3), 1.60 (d, CH.sub.3).

APPLICATION EXAMPLE

Example A1

Photocuring of a Radically Polymerizable Composition

(25) Formulation A: Polyether/Polyester Acrylate Varnish

(26) A photocurable acrylate varnish composition is prepared by mixing the following ingredients:

(27) 80% of Laromer PO94F (polyether acrylate containing amino groups, provided by BASF)

(28) 20% of Laromer PE9079 (polyester acrylate; provided by BASF)

(29) Formulation B: Epoxy Overprint Varnish

(30) A photocurable epoxy overprint varnish composition is prepared by mixing the following ingredients:

(31) 47.8% Laromer LR8986 (aromatic epoxyacrylate; BASF),

(32) 38.0% Laromer P077F (polyether acrylate containing amino groups, BASF),

(33) 14.0% Laromer DPGDA (tripropylen glycol diacrylate. BASF)

(34) 0.2% EFKA 3030 (organically modified polysiloxane levelling agent, EFKA)

(35) The compound to be tested (listed in Table 1 below) is dissolved in the liquid radically curable coating formulation A or in formulation B. This solution is then applied with spreading knife on a white cardboard (100150 mm, 12 m wet film thickness). The cardbord specimens are placed in an IST-METZ photocuring apparatus with moving belt and cold mirror reflector and are then photocured by irradiation under air with a mercury low pressure lamp (200 W), mounted 1.5 cm above the belt. The quality of the photocuring is assessed immediately after the irradiation by dry rub resistance (DRR) test: satisfactory curing is achieved when the coated surface is free from any trace after wiping with a paper tissue. Reactivity of the photoinitiator is quantified by the cure speed defined as the maximum belt speed (in m/minute) at which satisfactory cure (passed DRR test) is still obtained.

(36) The results are summarized in Table 1. Table 2 summarizes comparison compounds, tested in the identical formulations.

(37) TABLE-US-00001 TABLE 1 Compound of example No. Radically curable Curing speed (weight %) coating composition [m/s] 1 (4%) Formulation A 80 1 (4%) Formulation B 60

(38) TABLE-US-00002 TABLE 2 Compound Radically curable Curing speed (weight %) coating composition [m/s] Irgacure 184 *.sup.1 Formulation A 55 (4%) Darocur 1173 *.sup.2 Formulation A 65 (4%) Irgacure 2959 *.sup.3 Formulation A 60 (4%) Irgacure 184 *.sup.1 Formulation B 55 (4%) *.sup.1 Phenyl-1-hydroxycyclohexyl ketone (provided by BASF) *.sup.2 2-Hydroxy-2-methyl-1-phenyl-propanone (provided by BASF) *.sup.3 2-Hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone (provided by BASF)

Example A2

Comparison of Volatility

(39) The substantially lower volatility of the inventive compounds is demonstrated by performing the thermogravimetric analysis (TGA). A small sample (about 10 mg) is heated under nitrogen at 10 C./min in the open crucible of the TGA apparatus. A temperature after which 10% of the sample has evaporated is recorded. The higher this temperature is, the lower the volatility is. The results are collected in table 3.

(40) TABLE-US-00003 TABLE 3 Temp. until 10% Specimen weight loss ( C. ) Compound of example 1 287 Irgacure 2959 *1 216 Dacorur MBF *2 134 Darocur 1173 *3 113 *1 2-Hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone (provided by BASF) *2 methyl-oxo benzeneacetate *3 2-Hydroxy-2-methyl-1-phenyl-propanone (provided by BASF)