CS214670B2 - Method of photopolymeration of non-saturated compounds - Google Patents

Description

The invention relates to a process for photopolymerization of unsaturated compounds using aromatic-aliphatic ketones which are substituted in the α-position as photo-initiators.

Photochemical polymerization processes have gained considerable importance in the art, especially in those cases where thin films have to be cured in a short time, such as when curing coatings of paints or drying inks. UV radiation in the presence of photoinitiators has a number of advantages over conventional curing processes, the most important of which is the high cure rate in the presence of photoinitiators. This rate is highly dependent on the photoinitiator used and therefore there is no lack of attempts to replace existing initiators with ever better and more efficient compounds. The most potent photoinitiators include benzoin derivatives, in particular benzoinethers, as described, for example, in German Patent No. 1694149, α-hydroxymethylbenzoin derivatives as described in DOS 1 923 266, as well as dialkoxyacetophenones and benzil monoketals, as described in e.g. DOS 2,261,383, or 2,232,365. Α-aminoacetophenones and α-diaminoacetophenones recently proposed in U.S. Pat.

No. 048,034 and α-hydroxy-α-alkyl acetophenones and their ethers proposed as photoinitiators in DOS 2,357,866.

A disadvantage of these known photoinitiators is, for example, the poor storage stability of the photopolymerizable systems which are mixed with such initiators in the dark. Some benzoin derivatives tend to yellow materials that are cured with their help. Other photoinitiators have insufficient reactivity, which manifests itself in relatively long curing times, or is too poorly soluble in photopolymerizable systems or rapidly inactivated by atmospheric oxygen.

Thus, there is a need in the art for photoinitiators that are well soluble in the substrate and that, with good storage stability in the dark, induce photopolymerization more rapidly and provide a higher polymer yield per unit time than known photoinitiators. Using such improved photoinitiators, the costly industrial ultraviolet light irradiation equipment could be better utilized.

It has now been found that the compounds of the following formula I have the desired properties as photoinitiators, in particular they allow rapid polymerization and do not have the indicated advantages or have these disadvantages to a substantially lesser extent than the known photoinitiators.

The invention therefore relates to a process for the photopolymerization of unsaturated compounds of the formula I, in which n is 1 or 2,

Ar when n = 1 is phenyl, tetrahydronaphthyl or phenyl which is substituted one or more times with chlorine, bromine, C 1 -C 4 alkyl, C 1 -C 4 alkoxy or phenoxy, and v when n = 2, -phenylene-T-phenylene, where T is -O-, -S- or -CH2-,

X is one of — NR ⁴ R ⁵ , —OR ^6, or - OSi (CH 3) 3,

R ¹ represents an alkyl group having 1 to 6 carbon atoms or a group -CH 2 CH 2 COOalkyl wherein the alkyl contains 1 to 4 carbon atoms,

R ² has the same meaning as R ¹ or together with R ¹ is alkylene having 4-5 C atoms,

R ⁴ and R ⁵ represent a C 1 -C 4 alkyl group or R ⁴ and R ⁵ together with the nitrogen atom form a piperidine, morpholine or piperazine ring,

R ⁶ is hydrogen, C 1 -C 6 alkyl, C 3 -C 6 alkoxyalkyl or allyl as photoinitiators.

Examples of compounds of formula I wherein n = 1 useful in the invention include:

2-hydroxy-2-methylpropiophenone,

2-hydroxy-2-ethylpropiophenone,

2-hydroxy-2-butylpropiophenone,

2-methoxy-2-methylpropiophenone,

2-hydroxy-2-methyl- (p-chloropropiophenone J), 2-hydroxy-2-methyl- (3,4-dichloropropiophenone),

2-hydroxy-2-methyl- (p-methoxypropiophenone),

2-hydroxy-2-methyl- (2,4-dimethoxypropiophenone),

2-hydroxy-2-methyl- (p-phenoxypropiophenone), 2-hydroxy-2-methyl- (p-acetylaminopropiophenone),

2-hydroxy-2-methyl- (p-meethylpropiophenone),

2-methoxy-2-methyl- (o-methylpropiophenone),

2-hydroxy-2-methyl- (m-methylpropiophenone),

2-hydroxy-2-methyl- (2,4-dimethylpropiophenone),

2-hydroxy-2-methyl- (3,4-dimethylpropiophenone),

2-hydroxy-2-methyl- (p-butylpropiophenone),

2-hydroxy-2-methyl- (p-tert-butylpropiophenone),

2-hydroxy-2-methyl- (p-isopropylpropiophenone),

2-methoxy-2-methyl- (o-chloropropiophenone),

2-methoxy-2-methyl- (o-methylpropiophenone),

2-Phenoxy-2-methylpropiophenone, *

2-allyloxy-2-methylpropiophenone,

2-ethoxy-2-methylpropiophenone,

2-Methoxyethoxy-2-methylpropiophenone

3-Benzoyl-3-hydroxyheptane;

2-Benzoyl-2-hydroxypentane

3-Benzoyl-3-hydroxypentane

2-dimethylamino-2-methylpropiophenone,

2-diethylamino-2-methylpropiophenone,

2-Dibutylamino-2-methylpropiophenone

2-piperidino-2-methylproplofenone,

2- (2-methylpiperidino) -2-methylpropiophenone

2-morpholino-2-methylpropiophenone,

2-piperazino-2-methylpropiophenone,

2- (2-methylpiperidino) -2-imethylpropiophenone

1-Benzoylcyclohexanol

1-Benzoylcyclopentanol

1-Benzoylcyclopropanol

3-p-methoxybenzoyl-3-dimethylaminoheptane,

6- (2-hydroxyisobutyrs 1J tetralin),

6- (2-diimethylaminoilobutyryl) tetralin,

6- (2-morpholinoisobutyry 1J tetralin),

6- (2-piperidino-butyryl J tetralin),

6- (2-piperazino-butyryl) tetralin,

1-Methyl-2-o-chlorobenzoylpiperidine

2-o-Toluyl 1-2- (trimethylsiloxy) propane a

2-hydroxy-2-methyl- (p-isopropyl) -propiophenone.

Examples of compounds of formula I wherein n = 2 include: _t

4,4‘-bis- (α-hydroxyisobutyryl) diphenyl oxide,

4,4 ‘-bis- (α-hydroxyisobutyryl) diphenylsulfid

4,4-bis- (α-hydroxyisobutyryl) diphenylmethane,

4,4‘-bis (α-piperidino-butyryl) diphenyl oxide a

4,4‘-bis- (1-benzoyloxyisobutyryl) diphenyl oxide.

The compounds of formula I are partly known compounds, partly novel compounds. These novel compounds can be prepared according to known methods or analogously to these methods.

Thus, compounds of formula I can be prepared from aromatic-aliphatic ketones via the following reaction steps:

Br,

Ar '

CO-CHR ¹ R ^Z

CO-CBrR ¹ R ²

CH ^ QN *

ArI

OCH,

HX

Aro P *

CC — Λ i ₂

R ² ·

The amines [C. L. Stevens, Ch. Hung Chang,

J. Org. Chem. 27 (1962), 4392] or water [C. Stevens L., Farkas E., Am. Chem. Sec. 74 (1952), 618 and C.L. Stevens, S.J. Dykstra, J. Am. Chem. Soc. 75 (1953), 5976].

In many cases, the direct reaction of α-bromoketones to produce compounds of formula I is also successful,

ArCO-CBr R ¹

HX

Ar0 • C-C-X * 2

R ^z (i) with, for example, amines, alkali metal hydroxides or alkali metal phenoxides. Corresponding chloro derivatives can also be used instead of bromo derivatives.

The hydroxyketones of the formula I thus obtained (X = OH) can be etherified or O-silylated by conventional methods. Further details follow from the attached examples.

According to the invention, the compounds of the formula I can be used as initiators for the photopolymerization of unsaturated compounds or mixtures containing such compounds.

Such compounds may be acrylic or methacrylic acid monomeric esters, for example methyl, ethyl, n- or tert-butyl, isooctyl or hydroxyethyl acrylate, methyl or ethyl methyl acrylate, ethylenediacrylate, neopentyl diacrylate, trimethylolpropane tris acrylate, pentaerythritol tetraacrylate; they may also be oligomeric or polymeric acrylates which are obtained by esterification of oligomers or polymers containing hydroxyl groups with acrylic or methacrylic acid. Examples include acrylates of polyesters, polyurethanes or epoxy resins containing hydroxy groups. Such compounds are also referred to as acrylator resins. They are used primarily in combination with monomeric bis-, tris- or tetraacrylates as binders for UV-curable lacquers.

Other unsaturated compounds for which the compounds of formula I are suitable as photoinitiators are the so-called unsaturated polyester resins. These consist of unsaturated polyester and unsaturated monomer. The latter are simultaneously crosslinkers and solvents. Mostly unsaturated polyester resins are solutions of maleic acid copolyesters in styrene.

Photopolymerizable compositions, as used for various purposes, contain, in addition to photopolymerizable compounds and photoinitiators, a number of other ingredients. Thus, it is often customary to add thermal inhibitors which are primarily intended to protect during premixing of the system by premixing the components. For example, hydroquinone, hydroquinone derivatives, p-methoxyphenyl, β-naphthylamine or (3-naphthols) may be used, and small amounts of UV light absorbers such as the benzotriazole or benzophenone type may be added.

Copper compounds such as naphthenate, stearate or octoate of copper, phosphorus compounds such as triphenylphosphine, tributylphosphine, triethylphosphite, triphenylphosphite or tribenzylphosphate, quaternary ammonium compounds such as tetramethylammonium chloride or trimethylbenzylammonlumine may be added to increase storage stability in the dark. N-diethylhydroxylamine. In addition, the photopolymerizable systems may comprise chain transfer agents such as N-methyldiethanolamine, triethanolamine or cyclohexene.

Paraffin or similar waxy substances are often added to photocurable systems to avoid the inhibitory effect of air oxygen. They float at the beginning of the polymerization due to the lack of solubility in the polymer and form a transparent coating that prevents air from entering. Air oxygen can also be deactivated by introducing self-oxidizing groups, such as allyl groups, into the cured resin.

The photoinitiators can also be used in combination with radical initiators such as peroxides, hydroperoxides, ketone peroxides or percarboxylic acid esters.

The photopolymerizable systems further contain, depending on the purpose for which they are used, fillers such as silicic acid, talc or gypsum, pigments, dyes, fibers, thixotropic agents or auxiliaries.

They can also be used in combination with known photoinitiators such as benzoinethers, dialkoxyacetophenones or benzil ketals.

Particularly for photopolymerization of thin layers and printing inks, combinations of photoinitiators according to the invention with amines and / or aromatic ketones can be used. Examples of amines include triethylamine, N-methyldiethanolamine, N-dimethylethanolamine or p-dimethylaminobenzoic acid ester. Examples of ketones include benzophenone, substituted benzophenone derivatives, Michler ketone, anthraquinone and anthraquinone derivatives, as well as thioxantone and its derivatives.

Curing by photoinitiators for printing inks is of great importance since the drying time of the binder is an important factor for the speed of production of graphic products and can be in the order of fractions of a second.

Another field of application of UV curing is the formation of layers on metals, for example in the coating of sheet metal for tubes, jars or bottle caps, as well as ultraviolet curing of layers of plastics, such as PVC-based floor coverings or wall coverings.

Examples of ultraviolet light curing layers on paper are colorless label lacquers, record covers, or book covers.

Photoinitiators for the fields of application are used preferably in an amount of from 0.1 to 20% by weight, preferably in an amount from about 0.5 to about 5 weight ⁰ /) based on the unsaturated compound.

The addition of photoinitiators to the photopolymerizable compositions is generally done by simple mixing, since most of these systems are liquid or well soluble. In most cases, the initiator solution according to the invention is used, thus ensuring uniform distribution and transparency of the polymers.

The polymerization is carried out according to known photopolymerization methods by irradiation with light rich in shortwave radiation. Suitable light sources are, for example, medium-pressure, high-pressure and low-pressure mercury lamps, as well as super-active tubes with luminous substances whose emission maximums are in the range between 250 and 400 nm.

The production and use of the photoinitiators of the invention are described in more detail in the following examples. In these examples, parts are parts by weight, percentages are percentages by weight, and temperatures are in degrees Celsius.

Production and properties of the compounds used in Examples 1 to 6

The preparation of the compounds listed in Table 1 is carried out according to one or more of the methods A to L.

Method A

Chlorination of aromatic-aliphatic ketones ·

ArJCO — CR ¹ R ² H] _n + n Cl ² -> Ar [CO — CR ¹ R ² Cl] "+ n HCl •

In this method, the ketone is dissolved in a suitable inert solvent, preferably carbon tetrachloride, and a calculated amount of chlorine is introduced into the solution at a temperature of 40-80 °. Nitrogen is then introduced to remove dissolved hydrogen chloride. Finally, the solvent is distilled off. Purification of the obtained chloroketone is generally not necessary, and the product can then be reacted according to Method D,

F or H.

Method B

Bromination of aromatic-aliphatic ketones

Ar [CO — CR ¹ R ² H] n + n Bn - Ar [CO — CR ¹ R ² Br] n -J- n HBr

In this method, a calculated amount of bromine is added dropwise to the ketone solution at room temperature, for example in carbon tetrachloride. Processing and further processing are carried out according to Method A.

Method C

Chlorination with sulfuryl chloride

Ar [CO — CRiRZRHn + n SO2 Cl2 - * Ar [CO — * —CR ¹ R ² —Cl] _n + n SO2 + n HCl

Sulfuryl chloride was added dropwise at 40 ° C to a solution of the ketone in carbon tetrachloride. The treatment and further processing are carried out as for method A.

Method D

Production of epoxide as intermediate θ

AriCO-CR-R ¹ ΗιΙ / _α + η N ^ OCH ^ AriC ^ tRIR ² ^ + & Nartaí Hal = Qt or Br

The haloketone was dissolved in methanol and a solution of a stoichiometric amount of sodium methoxide in methanol was added dropwise at reflux temperature. Then the methanol was distilled off, the residue was poured into ice water and extracted with ether. The ethereal solution was washed with water, dried over sodium sulfate and evaporated.

se. The residue is purified by recrystallization or vacuum distillation. The epoxide can then be used for the reaction of Method E or G.

Method E

Hydrolysis of epoxides

Ar - O \ x 9 • C - cr ^ ² · OCHL -> Ar (CO-CR * rZqH) ^ + and CH ^ OH

The epoxide is poured over 2 to 5 times by weight of water and the mixture is refluxed for 1-2 hours with the addition of a catalytic amount of mineral acid. After cooling, it is extracted with ether, the ether solution is washed with water, dried over sodium sulphate and evaporated. The residue (crude hydroxyketone) is purified by distillation or crystallization or by column chromatography.

The properties of pure α-hydroxyketones are shown in Table 1.

Method F

Preparation of α-hydroxyketones from α-haloketones

Ar [CO - CR 1 R 2 Hal] _n + n NaOH -> Ar [CO - CRWH] "+ n NaHal w Halogen ketone is heated in a dilute or concentrated sodium hydroxide solution (20% excess sodium hydroxide) under reflux. The crude hydroxyketone is isolated as described for Method E and purified in the same manner.

Pure hydroxyketones are shown in Table 1.

Method G

Production of α-aminoketones from epoxides

". <*** ·. ·

Ar (C — n R ^ NH- ^ AriCO-CR ^ R-NR ^ h * and ₅ ....... ................ + nCH ^ OH

Epoxides either without solvent or with the addition of small amounts of toluene or xylene are mixed with the addition of stoichiometric amounts of amine and allowed to react for about 10-20 hours at temperatures from 100 to ^200! ° C. For low boiling amines, such as dimethylamine or diethylamine, the reaction is carried out in an autoclave. The reaction mixture was diluted with benzene and the diluted mixture was extracted with dilute hydrochloric acid. The aqueous acid solution was basified with sodium hydroxide, extracted with ether, the ether solution was washed with water, dried over sodium sulfate and evaporated. The crude product obtained is purified by distillation or crystallization.

α-Aminoketones are listed in Table 1.

214B70

Method Η

Preparation of α-aminoketones from α-haloketones

Ar [CO — CR ⁴ R ² Hal] _n + 2n R ⁴ R ⁵ ->

- Ar [CO — CR ¹ R ² —NR ⁴ R ⁵ ] _n + + n R ⁴ R ⁵ NHaHal α'-Haloketone is heated undiluted or diluted with toluene with 2 mol equivalents of amine for 10 to 20 hours at 100 to 200 ° C. In the case of low-boiling amines such as dimethylamine or diethylamine, the reaction is carried out in an autoclave. Isolation and purification are carried out in the same manner as for Method G.

Method I

Introduction of alkoxycarbonylethyl group

Ar [CO - CHR ^{1 -} X] n + CH 2 = = CH - COOAlk ->

CH 2 CH 2 COOAlk -> Ar [CO — CR ⁴ —X] _n

The ketone was dissolved in dimethylsulfoxide, 1.1 mol-equivalent of sodium hydroxide as a 4N sodium hydroxide solution was added to this solution, and 1.1 mol-equivalent of acrylate was added dropwise with cooling at room temperature. The reaction mixture was then diluted with ice water and extracted with toluene. The toluene solution was washed with water until neutral, dried over sodium sulfate and evaporated. The crude product is purified by column chromatography or crystallization.

Method K

Etherification of hydroxyketones

Ar [CO — CR ¹ R ² —OH] _n + n R · Hal = n NaOH - Ar [CO — CR ⁴ R ² —OR ⁶ ] _n + + n NaHal α-Hydroxyketone dissolves in about 4 times by weight 1 mol-equivalent of alkyl halide R ⁶ Hal and 1 mol-equivalent of concentrated sodium hydroxide solution are added dropwise from the two dropping funnels simultaneously with cooling to 10-20 ° C and stirring. The reaction mixture is stirred for 3 hours at room temperature, then the precipitated sodium halide is filtered off, the filtrate is diluted with ether, washed with water, dried over sodium sulphate and evaporated. The resulting crude product is purified by column chromatography, crystallization or vacuum distillation. Examples of useful halogen derivatives are methyl iodide, isopropyl bromide, allyl bromide, cyclohexyl bromide, benzyl chloride or ethyl chloroacetate.

Instead of an alkyl halide, it is also possible to use diacyl alkyl sulfate or alkylarylsulfonate as etherification agent.

Method L

Cyclization of residues X and R ¹ 'Ar-CO-CHhM-1f * CH 2 O-tAr-CO-CH 2 HAt - CH 2 OH

Ar-CO-C1-4H,

R *

Paraformaldehyde is dissolved in 20 times the amount of methanol. To this solution was added 1 mol-equivalent of sodium methoxide (dissolved in a small amount of methanol). With cooling to 0-5 ° C, a concentrated α-haloketone solution is added dropwise. The reaction mixture was then stirred at 5-10 ° C for 1 hour and at room temperature for 1 hour. The reaction mixture was diluted with ether to two to three times the volume of + N &lt; + &gt; H &lt; + &gt; CH &lt; 3 &gt; and then poured into ice water. The mixture was extracted three times with ether, the combined ether extracts were washed with water, dried over sodium sulfate and evaporated. The resulting crude product is purified by distillation or column chromatography.

Method M

Silylation of hydroxyketones

N- ^ CO-C ^ RQ ^ + n. (CH _{5) 3} Si-NH-Si (CH ^ + Catalyst F Π NH ^ Cl-CO-Rj-CRVO SÍÍCH ^

Hydroxyketone, disilazane and a catalytic amount (about 5 mol%) of 4-dimethylaminopyridine are introduced under nitrogen. To this end, a solution of chlorosilane in about 2 parts of hexane is added dropwise with stirring at room temperature. The cloudy reaction mixture was stirred for about 2 hours at 40 ° C, then slowly warmed to 110 ° and held at this temperature for about 15 minutes (until a sample by thin layer chromatography showed all hydroxyketone had reacted). The cooled suspension was diluted with ether, washed with water, the ether solution was dried over sodium sulfate and evaporated. The residue was distilled under high vacuum.

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Example 1

A resin mixture of 80 parts polyetheracrylate resin "Plex 6631" (manufactured by Röhin, Darmstadt), 20 parts trimethylolpropane tris acrylate and 2 parts photoinitiator is pulled onto a 40 µΐη glass film on a film extractor. These films are vented for about 20 seconds and then irradiated with a medium pressure mercury lamp (Hanovia model 45 080). The samples are moved on the conveyor belt at a speed below the UV lamp so that an effective irradiation time of 0.16 seconds is achieved per pass.

In Table 2 below, the second column shows the number of passes (D) that were required to obtain a wear resistant film.

Further, the storage stability of the resin-photoinitiator mixtures is determined. To this end, 5 g of each mixture is stored in the dark at room temperature for 30 days. The gel is checked daily. The time to gel formation is shown in the third column of Table 2.

used photoinitiator (always 2% j

Table 2 number of storage stability passes to obtain abrasion resistance (days) benzoinisobutyl ether No. 1 No. 2 No. 3 No. 4 No. 11 No. 20 No. 27 No. 28 No. 31> 30 30 30 18 30 24 26

Example 2% of the photoinitiator is dissolved in an unsaturated polyester resin (Crystic PEK 306, from Maeder, Killwangen, Switzerland). Films of 60 μτα thickness are then drawn out of these resin mixtures.

These films are irradiated as described in Example 1. The following Table 3 shows the number of passes under the irradiation apparatus up to the abrasion resistance of the films as well as the hardness measured by the Kegig pendulum after 12 passes.

used photoinitiator

Table 3 required number of passes to achieve abrasion resistance hardness measured by a Kegig pendulum after 12 passes

No. 2 8 89

No. 3 10 109

No. 4 7 112

Example 3

Resin blend consisting of 90 parts polyester-acrylic resin "Laromer LR 8496" (manufactured by BASF, Federal Republic of Germany), 10 parts hexanediol diacrylate, 0.5 parts "ByK 300" flow aid {product by ByK-Mallinckrodt, Federal Republic of Germany and 3 parts of a photoinitiator for curing in air, or 0.5 parts of a photoinitiator for curing under a nitrogen atmosphere, are applied by means of a 15 f <m spiral using electromotive force to the carton. After a short time to vent, the film is cured with an ultraviolet emitter (model PPG-QC-Prozessor) with a UV lamp of 80 Watt / cm. The following table 4 shows the maximum conveyor belt speed in m / min to obtain a non-stick film when working in air, optionally under nitrogen. In addition, storage stability in the dark at room temperature was determined.

Table 4 Photoinitiator used Movement speed (m / min) Air Nitrogen Storage stability at room temperature (days)

benzoinisopropylether 10 30 1 o 3 20 May 100 ALIGN! > 10 No. 4 10 120 > 10 No 5 20 May 100 ALIGN! > 10 No. 6 30 100 ALIGN! > 10 ič. 7 30 100 ALIGN! > 10 No 8 5 80 > 10 No. 9 5 80 > 10 No. 11 3.3 80 > 10 No 12 20 May 120 > 10 No 22 10 90 > 10 0. 23 20 May 90 > 10

Example 4

Resin blend consisting of 70 parts of polyester acrylate "Ebecryl 593" (manufactured by UCB, Belgium), 30 parts of trimethylolpropane trisacrylate, 0.5 parts of a flow aid "ByK 300" (manufactured by ByK-Mallinckrodt, Federal Republic of Germany), and 3 parts of the photoinitiator are applied to the glass plates by means of a 30-40 µm film coating frame. After a short time to vent, the film is cured with a laboratory UV-emitter (model PPG / Q.C-Prozessor) and a UV-lamp 80 Watt / / cm (2 passes). After UV-curing, the films are stored for% hour in normal climate and then the hardness is determined by a Konig pendulum instrument. Table 5 below shows the Kdnig pendulum hardness readings as a function of the speed under the lamp.

Table 5 Photoinitiator used (3%) Konig pendulum hardness vs m / min 25 m / min benzoinisopropylether No. 3 No. 4 No. 12 No. 13 No. 14 No. 15 No. 16 No. 17 No. 18 No. 21 No. 25 No. 29 No. 30 o 31 No. 32

130

154

163 156

138

150 160 160

155

151 161 146

140 162 153

164

146 154

147 137 132 152 144 143 127 154 129 116 149 131 152

Example 5

Various photoinitiators were tested at a concentration of 2% using the resin mixture of Example 1 using the procedure described therein. All samples were illuminated for the same duration, each with 2 passes at a speed of 20 m / min. Half of the samples were irradiated in air and the other half under nitrogen. For irradiated samples, the KSnig pendulum hardness was measured after 30 minutes. The values obtained are shown in Table 6.

II

Table 6 used photoiniculator pendulum hardness in s at irradiation (always 2%) in air in nitrogen atmosphere

benzoinisopropylether 132 131 No. 4 182 184 No. 10 177 185 No 19 148 162 No 26 145 151 No 33 169 177 No 34 178 201 No 35 146 143 E. 36 154 200 No 37 165 174 No 38 161 141

Example 6

Blue printing ink is produced according to the following recipe:

parts of acrylate resin "Setalin AP 560" (manufactured by Synthese, The Netherlands) parts of 4,4'-di (β-acryloyloxyethoxy) diphenyl-2,2-propane (Ebecryl 150) parts of blue pigment "Irgalith GLSM" (manufactured by CIBA- GEIGY, Basel)!

parts of N-methyldiethanolamine 4 parts of compound 4 as photoinitiator

100 ALIGN!

First, the "Setalin" acrylic resin is ground together with the blue "Irgalith" pigment in a dye paste ball mill. N-Methyldiethanolamine and photoinitiator are dissolved in 4,4‘-di - (β-acryloyloxyethoxy) diphenyl-2,2-propane and this solution, together with the coloring paste, is homogenized on a plate spreader.

The printing paste thus obtained is printed on a special paper.

Quantity of printing paste 2 g / m ² Thrust 25 kp / m ^z Print speed 1 m / s The printed samples are irradiate with UV emitter

(80 W / cm lamp, 11 cm lamp distance). The irradiation time is changed by changing the speed of the belt moving under the lamp. Surface drying is determined by a wipe test. In doing so, they press the white paper at 25 kp / cm ² . If the paper remains white, the test result is positive. This is the case for all samples that have been irradiated at a conveyor belt speed of not more than 75 m / min.

For comparison, a printing paste was prepared in which benzoin isobutyl ether was used as photoinitiator and otherwise in a composition corresponding to the recipe described above. In analogous testing of surface drying with a wipe test, it has been found that a conveyor belt speed of not more than 15 m / min can be used to give a positive result.

The printing paste contains Compound No. 4, is stable in the dark for at least 30 days, while the printing paste containing benzoinisopropyl ether gel already after 1 day.

Claims (1)

Method photopolymerization of unsaturated compounds, especially monomeric or polymeric esters of acrylic or methacrylic acid or of unsaturated polyester resins in the presence fotoiniciátoíů, characterized in that the photoinitiator used is a compound of formula I, and if I ⁰ • C - C Ar- (I) wherein n is 1 or 2, Ar when n = 1 is phenyl, tetrahydronaphthyl or phenyloxy substituted one or more times with chlorine, bromine, C 1 -C 4 alkyl, C 1 -C 4 alkoxy or phenoxy, and v when n = 2 is -phenylene-T-phenylene, where T is -O-, -S- or -CH 2 -, X is one of — NR ⁴ R ⁵ , —OR ^6, or — OSi (CH ₃ ) ₃ , R ¹ represents an alkyl group having 1 to 6 carbon atoms or a group -CH 2 CH 2 COO-alkyl wherein the alkyl contains 1 to 4 carbon atoms, R ² has the same meaning as R ¹ or together with R ¹ represent lalkylenovou group having 4-5 carbon atoms; R ⁴ and R ⁵ represent a C 1 -C 4 alkyl group or R ⁴ and R ⁵ together with the nitrogen atom form a piperidine, morpholine or piperazine ring, R ⁶ is hydrogen, (C 1 -C 6) alkyl, (C 3 -C 6) alkoxyalkyl or allyl,