DE2022507C2 - Salts of ketovaleric acids and their use as photoinitiators in the aqueous phase - Google Patents

Description

The invention relates to compounds of
formula

R ^{1 is} hydrogen, alkyl up to 4 carbon atoms, cycloalkyl up to 6 carbon atoms or phenyl,

R ^{2 is} hydrogen or methyl,

X is a mono- or divalent metal cation or an ammonium cation and

η mean 1 or 2.

Another object of the invention is the use of these compounds as photoinitiators for Photopolymerization of polymerizable compounds or mixtures of compounds in aqueous solution or aqueous dispersion.

Examples of salts according to the invention are those in which R ¹ , R ² and X have the following meanings:

Table 1

R ¹ R ² X M.p. ("C) IR (KBr)) W, (em "') 1 H H N / A > 200 1670 and 1565 2 H H K > 200 1675 and 1570 3 CHj H N / A > 260 1675 and 1570 4th CH, H K > 260 1675 and 1565 5 CHj H Li not Krist. 1675 and 157O (cHCl ₃ ) 6th CjH ₅ H Li not Krist. 1670 and 1565 7th CjH, H N / A > 260 1675 and 1565 8th CjH ₇ H N / A > 26O 1675 and 1570 9 CjH ₇ H X > 260 1670 and 1580 IO i-CjH ₇ H N / A > 260 1670 and 1570 Π JC ₃ H ₇ H K > 260 1670 and 1575 12th i-CjH, H Li not Krist. 1670 and 1570 13th SC ₃ H ₇ H Triethylamine · H not Krist. 1675 and 1570 14th i-CjH ₇ H Morpholine · H not Krist. 1675 and 1575 15th nC ₄ H, H N / A > 260 1675 and 1570 16 n-C, H, H K > 26O 1675 and 1575 17th cyclo-QH ,, H N / A > 200 1670 and 1570 18th C ₆ H, H Li not Krist. 1675 and 1570 19th CjH, CHj N / A > 200 1675 and 1575

Generally as cations X come into question e.g. ammonium, lithium, sodium, potassium, magnesium, Calcium, zinc and those produced by protonation of nitrogen bases, ζ. B. methylamine, triethylamine, benzylamine, Aniline, cyclohexylamine, hydrazine, morpholine, Piperidine, hexamethylenediamine and pyridine, formed substituted ammonium cations.

The acids of the salts according to the invention are in a manner known per se by Michael addition corresponding benzoins or benzoin ethers on acrylic or methacrylic acid ester and subsequent saponification of the ester group available. Some of them are known; vgL Chem. Zentralblatt 1968, No. 29, p. 117, Referat 1112, and FR-PS 20 13 828.

It has already been proposed to use hydroxy-ketovaleric acids, their esters, amines or lactones (BE-PS 7 41 343) or their nitriles and the alkyl, aryl and Aralkyl ethers of these compounds (FR-PS 20 13 828 s DE-OS 17 69 854) as initiators for the photopolymerization of polymerizable compounds or mixtures to use. Photopolymerizations in the aqueous phase are not mentioned in these parts of the literature.

The salts according to the invention allow for the first time photopolymerizations in aqueous solution or dispersion with good result. This has many advantages: There is no need for organic solvents so that there are no precautions to protect against solvent vapors; despite absence Organic solvents can be easily adjusted to the desired viscosity by adding water; the systems to be polymerized are pumpable and therefore easy to transport and manageable. These advantages in connection with high quality polymers represent a considerable one Progress and a high level of inventive achievement.

Compounds which can be photopolymerized with these initiators are suitable as polymerizable olefins, their double bonds) by halogen atoms or nitrile, carbonyl, carboxy, carbalkoxy, carbonamido, ether or aryl groups are activated. Examples include: acrylamide, acrylonitrile, N-methylolacrylamide, ethyl acrylate and vinyl chloride. Mixtures of various monomers and their mixtures with unsaturated monomers are also suitable Polyesters containing residues of -unsaturated dicarboxylic acids.

As a light source to carry out the photopolymerization Sunlight or artificial UV emitters can be used, which range from about 250 to about 500 nm, preferably from about 300 to about 400 nm. Suitable are e.g. B. Mercury, Tungsten and xenon lamps. Low-energy emitting ultraviolet and visible light can also be used Fluorescent lamps (emission from about 300 to about 580 nm) and certain fluorescent lamps as Serve spotlights.

The compounds are characterized by high reactivity and general applicability towards almost all polymerizable substances, especially when exposed to long-wave UV light generally in amounts from about 0.001 to about 10, preferably from about 0.01 to about 2.5 percent by weight, based on the substance to be polymerized, either alone or in admixture with one another Photoinitiators which are formally different from benzoin ethers have a particularly high reactivity derive primary alcohols, e.g. 4,5-diphenyl-5-keto-2-n-butyloxy-sodium valerate

example 1

To the solution of 100 g of benzoin ethyl ether in 200 ml of dimethylsulfoxide C 4 ml of 4N sodium hydroxide solution are added at 20 ⁰ and then added dropwise with stirring 45 ml of methyl acrylate After 2 hours, the solvent is distilled off in vacuo and the residue (149 g) with 700 ml 4- percent methantlischer ίο sodium hydroxide solution at 30 ⁰ C saponified After the usual work-up (acidification) 109 g of 4,5-diphenyl-5-keto-4-ethoxy-valeric acid of mp. 186-190 ⁰ C obtained.

C ₁₉ H2o04 (312.4) Acid number: 175
IR (KBr) 171Ou. 1675 cm- ^:

Ber. C 73.06 H 6.45 020.49%
Found C 7330 H 6.57 0 2030%

93.6 g of 4,5-diphenyl-5-keto-4-ethoxy-valeric acid are suspended in 50 ml of ethanol and, after adding 150 ml of water, neutralized with n / l potassium hydroxide solution evaporating the solution in vacuo and drying the residue at 80 ° C / 0.05 Torr (0.067 mbar 106 g of crystalline 4,5-diphenyl-5-keto-4-ethoxy-potassium valerate remain

Ci ₉ H ₁₉ KO * (350J) m.p. > 270 ° C
IR (KBr) 1675 and 1570 cm- '

Ber. C 65.1 H 5.5%
Found C 64.6 H 5.7%

Example 2

According to Example 1, 101.6 g benzoin ipropyläther reacted in 200 ml of dimethyl sulfoxide in the presence of 8 ml of 4N sodium hydroxide solution with 44.5 ml methyl acrylate The remaining after evaporation residue (153 g) is mixed with 340.0 ml 4 per cent sodium hydroxide solution in methanol hydrolyzed for 6 hours at 30 ⁰ C. after concentrating the methanolic solution of the reaction product is washed with water and ether added to the slightly alkaline (pH 75-8) reacting solution leaves at the concentration 124 g of crystalline 4,5-diphenyl-5-keto-4-i-propoxy-sodium valerate

The following examples describe the application. Example 3

In each case 10 ml of a 10 weight percent aqueous solution of N-methylolacrylamide are exposed after addition of 0.15 mmol (corresponding to about 05 weight percent) of the initiators listed below at 18 ° C under nitrogen for 30 seconds in the reactor mentioned in Example 3 ml diluted The content of vinyl monomers in the exposed solution is determined by conversion with bromide / bromate and back titration of the excess with thiosulfate. The following conversions of N-methylolacrylamide are obtained:

initiator

sales

(% N-Methylacrylnmid)

4,5-diphenyl-5-ketone-4-hydroxy-sodium valerate

4,5-dipheny! -5-keto-4-isopropoxy-sodium valerate 4,5-diphenyl-5-ketone-4-n-butoxy-sodium valerate 4,5-diphen} "I-5-keto-4-isopropoxy- Potassium valerate 4,5-diphenyl-5-keto-4-isopropoxy-lithium-valerate 4,5-diphenyl-5-keto-4-isopropoxy-ammonium valerate 6.8
28.0
54.3
35.5
29.5
30.0

Example 4

A needled fiber fleece (200-150 mm) made of polyamide-6 fibers is impregnated with an aqueous solution containing 30 parts by weight of N-methylolacrylamide, 30 parts by weight of triethylene glycol bisacrylate and 6 percent by weight of 4,5-diphenyl-5-keto-4- isopropoxy-containing sodium valerate By rapid cooling to -40 ⁰ C a cold surface solidifies the solution. At -10 ° C, exposure is carried out for 15 minutes using two fluorescent tubes (type Osram L 40 W / 70-1) and a water-cooled high-pressure mercury burner (type Philips HPK 125W) at a distance of 5 cm dried in the air The ^Λ 'ues treated in this way is permeable to air and has a soft grip.

Claims (2)

Patent claims: 1. Compounds of the formula OR ¹ wherein Ri is hydrogen, alkyl up to 4 carbon atoms, cycloalkyl up to 6 carbon atoms or phenyl, R ^{2 is} hydrogen or methyl, X is a mono- or divalent metal cation or an ammonium cation and η mean 1 or 2. 2. Use of the compounds according to claim 1 as photoinitiators for photopolymerization polymerizable compounds or mixtures of compounds in aqueous solution or aqueous Dispersion.