CA1243325A - Liquid thioxanthonecarboxylic acid esters - Google Patents
Liquid thioxanthonecarboxylic acid estersInfo
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- CA1243325A CA1243325A CA000484563A CA484563A CA1243325A CA 1243325 A CA1243325 A CA 1243325A CA 000484563 A CA000484563 A CA 000484563A CA 484563 A CA484563 A CA 484563A CA 1243325 A CA1243325 A CA 1243325A
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/004—Photosensitive materials
- G03F7/027—Non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds, e.g. ethylenic compounds
- G03F7/028—Non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds, e.g. ethylenic compounds with photosensitivity-increasing substances, e.g. photoinitiators
- G03F7/031—Organic compounds not covered by group G03F7/029
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D335/00—Heterocyclic compounds containing six-membered rings having one sulfur atom as the only ring hetero atom
- C07D335/04—Heterocyclic compounds containing six-membered rings having one sulfur atom as the only ring hetero atom condensed with carbocyclic rings or ring systems
- C07D335/10—Dibenzothiopyrans; Hydrogenated dibenzothiopyrans
- C07D335/12—Thioxanthenes
- C07D335/14—Thioxanthenes with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached in position 9
- C07D335/16—Oxygen atoms, e.g. thioxanthones
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- Spectroscopy & Molecular Physics (AREA)
- General Physics & Mathematics (AREA)
- Polymerisation Methods In General (AREA)
- Paints Or Removers (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
Liquid thioxanthonecarboxylic acid esters Abstract of the Disclosure Thioxanthonecarboxylic acid esters of formula I and mixtures thereof
Description
3:~
3-14996/+/ZFO
Liquid thioxanthonecarboxylic acid e~ters The present lnventlon relates to liquid thioxanthonecarboxylic acid ssters which contain polyoxaalkylene radicals in th~ ester group, to mlxtures of such esters with an organic amine or with a radical or cationic photoinitiator, and also to photopolymerisable systems that contain such mixtures.
Alkylthioxant`hone~ are disclosed as photoinitlators for UV curable resin systems in German Offenlegungsschrift 32 28 371. They are obtalned in liquid form and can therefore be dispersed in prepolymer formulations. These alkylthioxanthone~ have not gained acceptance for toxicologlcal reasons.
Thioxanthonecarboxylic acid esters are disclosed as photoiDitiators in German Offenlegungsschrlft 30 lS 891. Among the crystalline compounds, mention is also made of the ester of triethylene glycol monomethyl ether and thioxanthone-1-carboxylic acid, said ester being in the form of an oilO It has subsequently been found that this compound crystallise6 after a tim0. In addition to an in-sufficient ~helf-life, this crystallisation constitutes a furth~r substantial disadvantage for the production of this compound. Seed crystals formed during production can no longer be removed from the apparatus, which may result in crystallisation of the desired liquid compounds and thus in dlscontinuation of production.
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Thloxanthonecarboxylic acld eaters containing functional eater groups are deacribed in European publiahed patent applica-tion 0 033 720. Ihe diethylene and triethylene glycol asters of 7-methylthioxanthone-3-carboxylic acid referred to in thls publi-cation are solid compounds.
Liquid thioxanthones can be more readlly incorporated and dispersed in syatems which can be cured by irradiation. In addition, those thioxanthones are de3irable whlch can be disperaed or emulsified in liquid, eapecially aqueous, coating composition~.
Specifically, the present invention relates to liquid thioxanthone-carboxylic acid esters and liquid mixtures of thioxanthonecarbo~ylic acid ester~ of the formula I
~ ~CO-(OR) - ORl Y~ /il\ /il 4 ~ (I) wherein X is hydrogen, halogen, NO2, COOH, unsubstituted or alkyl-sub-stituted amlno, Cl-Czoalkyl, Cl-C2Galkoxy, Cl-C20alkylthio, Cl-C20alkylsulfoxyl, Cl-C2Dalkylaulfonyl, unsub~tituted or sub~tltuted phenoxy, phenylthio, phenylsulfoxyl or phenyl-sulfonyl, or i~ -COOR , wherein R i9 alkyl, cycloalkyl, aryl, alkaryl, aralkyl, alkaralkyl, hydroxyalkyl, alkoxyalkyl or free or othesifi~d polyoxaalkyl, Y ha~ in each caa~ independently the same meaning aa X, n is an integer from 4 to 2S, R ig linear or branched C2-C6alkylene, and R~ la hydrogen, alkyl or a radical of the formula II
~L~k33 CO
o S \- ~ (II) with the proviso that, if R is ethylene and Rl is hydrogen, n is an int~ger from 7 to 25 and, if R i9 ethylene and Rl 1~ methyl, n is an integer from 11 to 25.
Among the mlxtures, those whlch compounds of fonnula I are pre-ferred, whereln n has different value~, or mixtures of thos~
compounds of formula I, wherein Rl is, on the one hand, hydrogen and, on the other, 15 a radical of formula II, whlch mlxtures may addltionally contain compound~ of for~ula I in which n has different values.
X and Y a~ halogen are preferably bromine and, most preferably, chlorine or fluorine. X and Y as unsubstituted or alkyl-substituted amlno may be -NH2, -NHR2 or ~NR2, wherein R2 i~ l~near or branched alkyl of preferably 1 to 6 carbon atoms, phenyl, benzyl, cyclopentyl or cyclohexyl. Al~yl is for example methyl, ethyl, ~-propyl, lsopropyl, butyl, pentyl and hexyl.
X and Y es alkyl, and the alkyl molety of alkoxy, alkylthlo, alkylsulfoxyl and alkylsulfonyl groups X and Y, may be llnear or branched and preferably contain l to 12, in particular l to 6 and, most prefe~ably, 1 to 4 carbon atom~. Examples of such alkyl groups are: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, undecyl and dodscyl. X and Y a~. alkyl are preferably methyl~
Suitable substituentR of th~ phsnoxy, phenylthio, phonylsulfonyl and phenylsulfoxyl groups are, for example, Cl-C4alkyl and halogen such as fluorine, chlorine or bromine.
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Ra as alkyl contains preferably 1 to 6 carbon atoms and is, in particular, methyl or ethyl. Ra as cycloalkyl is preferably cyclo-pentyl and cyclohexyl. Ra as aryl i~ preferably phenyl and, as alkaryl, is preferably alkylphenyl containing 1 to 4 carbon atoms 1n the alkyl moiety. Ra as aralkyl is preEerably benzyl and, as alkaralkyl, ls preferably alkylbenzyl containing 1 to 4 carbon atoms in the alkyl moiety. Ra as hydroxyalkyl may be linear or branched and contalns preferably 2 to 6 carbon atoms. Ra as alkoxyalkyl preferably contains 3 to 12 carbon atoms and has in particular the formula -CXH2x-oR3, wherein x is an integer from 2 to 6, preferably from 2 to 4, and R3 is preferably C1-C~Oalkyl. Ra as free or etherified polyoxa~lkyl preferably has the formula -(CxH2xo)y~R4, wherein x is an integer from 2 to 6, preferably 2 to 4, and y is an integer from 2 to 25, preferably from 2 to 18 and, most preferably, from 2 to 12, and R4 i5 hydrogen or C1-C12alkyl, preferably C1-C6alkyl. Most preferably, R4 i8 hydrogen, methyl or ethyl.
X is preferably hydrogen. The radical Y is preferably bonded in the 7-posltion. In a preferred embodiment, Y is hydrogen or C1-C6alkyl 7 preferably methyl.
The -CO-(OR)n-OR1 group is preferably bonded in the 1- or 3-position.
R as alkylena i9 for example ethylene, 1,2- and 1,3-propylene, 1,2-, 1,3 and 1,4-butylene, 1,2-, 1,3-, 1,4- and 1,5-pentylene, and 1,2-, 1,3-, 1,4-, 1,5 and 1,6-hexylene. R i8 preEerably C2-CI,alkylene, most preferably ethylene, 1,2- or 1,3-propylene.
Rl as alkyl may be linear or branched and preferably contains 1 to 12, most preferably 1 to ~, carbon atoms. Examples of alkyl groups are those mentioned above for X. In a preferred embodiment, Rl is hydrogen, methyl, ethyl or a radlcal of the formula II.
~2~33~5 If R iB linear alkylene, n is preferably an integer from 9 to 25 and, if R i3 branched alkylenP, n is preferably an integer from 6 to 25.
In a prefsrred embodiment, n is an integer from 8 to 20, preferably from 8 to 18, most preferably from 8 to 14, if Rl is hydrogen or a radical of formula II. In another preferred embodiment, n i9 an integer from 11 to 20, most preferably from 12 to 18, lf Rl i~
aikyl.
In a particularly preferred subgroup, R i3 ethylene, Rl i9 hydrogen or a radical of formula II and n i3 an integer from 8 to 14, or R ls ethylene, R1 is methyl and n i8 an integer from 12 to 18.
The compounds of formula I and mixtures thereof are obtained by coDventional esterification procedure3 by reactlng thioxanthone-carboxyllc acids of formula ~ COOH
Y~ 11 1 ~X
S
or ester-forming derivatives thereof, e.g. acid esters or acid halides, with alcohols of formula Rs O-(RO)D H~
~herein Rs is hydrogen or alkyl. The reaction may be carried out in the presence of an inert organic solvent and at elavated tempera-ture, for example in the range from 50 to 200C. Examples of suitable inert 601vents are aromatic hydrocarbons such as benzene, toluene, xylene, chlorobenzene and 1,2 dichloroben7ene.
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In the esterification of the carboxylic acids or transPsterification of carboxylic acid esters, acids or metal compounds can be us2d as catalysts, for example hydrochloric acid, sulfuric acid and 3ulfonic acids, tetraalkylorthotitanates or dialkyltin oxides.
If Rs i9 alkyl, 1 equivalent of alcohol of the formula RsO-(RO)n~H
will preferably be used. If Rs is hydrogen, 0.5 to 1 equivalent of dialcohol of the formula HO-(RO)n-H may be used. Depending on the amount added, compounds of formula I are then obtained in which R
is hydrogen or a radical of formula II9 or mixtures of such compounds .
Thioxanthonecarboxylic acids and acid derivatives are known from German Offenlegungsschrift 30 18 891 and European published patent application 0 033 720, or they can be prepared by analogous procedures. The alcohols employed are also known and some are commercially available.
The compounds of formula I and mixtures thereof are liquid to oily substances which can be readily incorporated ln substrates.
Surprisingly, they are also distinguished by the feature that they have an insignificant tendency to cause yellowing.
The compound~ of formula I and mixtures thereof can be used together with hydrogen donors, especially with organic amines, as photoini-tiators for the photopolymerisation of ethylenically unsatura~ed compounds or for the photocrosslinking of polyolefins, as well as photoredox catalysts, for example for metal deposition without current. Accordingly, the invention alao relates to mixtures of A) at least one compound of formula I and B~ at least one organic amine, as initiators for the photopolymerisation of ethylenically compounds or for the photochemical crosslinking of polyolefins.
3~
The organic amines employed may be allphatic, aro~atic, araliphatic, cycloaliphatic or heterocyclic amines. They can be primary, secondary or tertiary amines. Examples of such amines are: butyl-amine, dibu-tylamine, tributylamine, cyclohexylamine, benzyldimethyl-amine, dicyclohexylamine, triethylamine, phenyl diethanolamine, piperidine, piperazine, morpholine, pyridine, quinoline, ethyl p-dimethylaminobenzoate or Michler 18 ketone (4,4'-bisdimethylamino-benzophenone).
Examples of pre.~erred aliphatic tertiary amines are trimethylamine, triethylamine, trllsopropylamine, trlbutylamine, dodecyldimethyl-amine, octyldim~thylamine, triethanolamine, tris(hydroxypropyl~-amine, ~-methyldiethanolamine or N-butyldiethanolamine.
The mixtures of this invention preferably contain the compounds of formula I and the organic amines in a weight ratio o 4-1 to 1:4.
Photopolymerisable compounds are, for example, unsaturated monomers, such as esters of acrylic acid or methacrylic acid, for example methyl acrylate, ~thyl acrylate, n- or tert-butyl scrylate, isooctyl ~crylate or hydroxyethyl acrylate, methyl methacrylate or ethyl methacrylate, ethylene diacrylate, butanediol diacrylate, hexanediol diacrylate, r.eopentyl diacrylate, trimethylpropane trisacrylate, pentaerythritol tetraacrylate or pentaerythritol trisacrylate;
acrylonitrile, methacrylonltrile, acrylamide, methacrylamide and N-substituted acrylamides and methacrylamides; vinyl esters, for example vinyl acetate, vlnyl propionate, vinyl acrylate or vlnyl succlnate; other vinyl compounds such as vinyl ethers, vinyl ketones, vlnyl sulfones, ~tyrene, alkylstyrenes, halostyrenes, divinylbenzene, N,N'-divinylurea, vinylnaphthalene, N-vinyl~
pyrrolidone, vinyl chloride or vlnylldene chloride; allyl compounds such as diallyl phthalate, diallyl maleate, triallyl isocy~nurate, triallyl phosphate or ethylene glycol diallyl ether, and the mixtures of such unsaturated monomers.
~ ~L~ ~ 3 ~ 5 The mixtures of this invention are particularly sultable for the photopolymerisation of acrylic acid ester~ and mixtures thereof.
Further examples are unsaturated acrylic resins. These include 9 for example, reac~ion products of polyepoxides (epoxy res~ns) with acrylic acid or methacrylic acid or reaction products of polyiso-cyanates with hydroxyalkyl acrylates, and also the reactlon products of hydroxylated polyesters or polyethers with acrylic acid or methacrylic acid. These unsaturated acrylic re~ins are generally used in admixture wlth one or more acrylates of a mono-, di- or polyalcohol, for example ethyl acrylate, butyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate or 2-hydroxypropyl acrylate, ethylene glycol diacrylate, propylene glycol diacrylate, butanediol diacrylate, hexamethylene diacrylate, trimethylolpropane tris-acrylate or pentaerythritol tetraacrylate.
The invention also relates to photopolymerisable systems comprising a) at least one ethylenically unsaturated compound, b) a mixture of A) and B) as defined herein and, if desired, c) other additives, such as inhibitors, stabilisers, W-absorbers, fillers/ pigments, dyes, thixotropic agents and levelling assistants, for example silicone oil.
Examples of inhibitors which are intended to provide protection a~ain~t premature polymQrisation, in particular during the prepara-tion of the systems by mixing the components, are hydroquinone, hydroquinone derivatives, p-methoxyphenol or ~-naphthol.
W-ab~orbers which can be used are, for example, those of the benztriazole or benzophenone type. Suitable fillers are, for example, silica, talcum, gla3s fibres, titanium dioxide or gypsum.
Preferred photopolymerisable systems of this type are those in which a) and c) are present in amounts of 99.5-80 % by weight and b) is present in an amount of 0.5-20 % by weight.
33%~
g An acrylate or a mlxture of several acrylates is preferably used as component a).
In particular, the photopolymerisable systems of the present invention are coloured systems whlch contain at least one pigment or one dye. Such systems are used in particular as printlng inks and as whlte lacquers.
A further Eleld of use of the compounds of formula I is as photo-sensltizers in conjunctlon with a radical or cationic photoinl-tiator. Radical photoinitiators are those which form radicals by photofragmentation. Known classes of radlcal photoinitiators are for example ben~oin ethers, halogenated acetophenones, benzll ketals, alkoxyacetophenones, i~obutyrophenones (as described for example in European published patent application 3002, DE-OS 2 722 264 or European published patent application 88050) or acylphosphine oxides (as described for example in European published patent applica-tion 7508). Cationic photolnitiators are those which, on irradia-tion, spllt off protons or Lewis acids. Known examples of such photoinitiators are aromatic sulfonium or iodonium salts.
The combinations with radical photoiniators are used for the photopolymerisation of the ethylenically un~aturated compounds specified above. The comblnations with cationic photoinitiators are used for photopolymerising cationically polymerisable compounds.
These may be cyclic ethers or thioether~, lactones, lactams or also specific vinyl compounds. Combinations with cationic photoinitiators are of particular importance for the ra~iation curing of epoxy resins.
The initiator mixtures according to the invention are of great importance for the photocuring of printing inks and white-pigmented coatings, as the drying time of the binder is a decisive factor in the production rate of printing yroducts and should be of ~33~;
the order oE magnltude of fractlons of a second. The initiators of the invention are also very suitable for photocurable systems for the production of prlnting plates.
A further fleld of application ls the UV curing of metal coatings, for example in the vanlsh coating of sheet metal for tubes, cans or bottle top3, and also the W curing of plastic coatings, for example floor coverlngs or wall coverings based on PVC.
Examples of the W curing oE paper coatings are the colourless varnish coating of labels, gramophone record sleQve3 or book ~ackets.
The mixtures of this invention can also be used as initiators for photochemical crossllnklng of polyolefins. Polyolefins which can be used are, for example, polypropylene, polybutylene, polyiso-butylene and copolymers, for example ethylene/propylene copolym2rs~
but preferably polyethylene of low, moderate or high density.
The addition of the preferred photoinitiators to the photopoly-~erisable systems is generally effected by simple stirring, as most of these systems are llquid or readily soluble. A solution of the initlators is obtained, ther~by ens~ring thelr uniform distribution and the transparency of the polymers.
The polymerisation is effected by the known methods of photopoly-merisation by lrradlation with light which is rich in short-wave radiation. Suitable light sources are, for example, medium pressure, high pressure and low pressure mercury lamps7 and ~150 superactinic fluorescent tubes, the emission peaks oE which are in the range from 250 to 450 nm.
For the photochemlcal crosslinking of polyoleEins, the photoiniator i~ added to the polyolefin before or during processing to ~haped articles. Crosslinking is effected by irradiating the shaped article in solid form, or example in the Eorm of sheets or f:Llaments.
33%~
The compounds of formula I are al~o suitable for use as sensitizers for photocrosslinka'ole polymers of the most widely different kind.
Such polymers are used, for example, for preparing photographlc offset varnlshes for unconventional photography, for example for obtaining photographic images by photopolymerisation or photocross-linking. Such polymers are used in particular as photoresists for making printed circuit~ by methods which are known per se. This i3 done by exposing the side of the printed circuit board containing the light-sensitive layer with a negatlve transparency of the conductive pattern and then developing it by dis~olving out the unexposed areas of the layer with developing fluid.
The polymers employed may be any materials whose light sensitivity (sensitivity to actinic rsdiation) can be enhanced by the use of the compounds of formula I. The compounds of formula I are most parti-cularly suitable for use as sensiti~ers for the polymers disclosed 1n DE-OS 26 26 769, the light-sensitive groups of which have the formula ,Q ,Gl \-/ \G
a 2 wherein Gl and G2 are each independently of the other Cl-C4alkyl, preferably methyl, or Gl and G2, when taken together, complete a 5-or 6-membered carbocyclic ring.
The compounds of formula I can be incorporated in the photocrossllnk-abla polymers in a manner known per se. The amount of compounds of formula I in the polymer can vary greatly, depending on the end use and on the number of photocrosslinkable groups present in the polymer, but is usually from about O.l ~o 20 % by weight, based on the weight of the mixture.
~2~3~
The compounds of fDrmula I of the present inventlon are particularly suitable for aqu~ous coating compositions which can be cured by irradiatlon, as they can be readily emulsified and dlstrlbuted because of their llquid character. An even distribution in a produced layer iB al90 thereby achleved. After lrradiating such a layer, a more level curing is also achieved.
The following Examples illustrata the invention ln more detail.
Example 1: Polyethylene ~1YCO1 400 monoester of thioxanthone~l-carboxylic acid (n ~ 9) 25.63 g (100 mM) of thioxanthone-1-carboxylic acid, 40.00 g (100 mM) of polyethylene glyrol 400 (available from Fluka, average ~olecular weight: 380-420), 150 ml of o-dichlorobenzene and 138 mg of concentrated sulfurlc acld are heated to reflux for 35 minutes (bath temperature 200C), while separatlng off the water of reactlon vla 8 water trap. After it has cooled, the solutlon ls stirred wlth anhydrous potassium carbonate and then filtered. The mother liqusr ls concentrated by evaporation, flrst at 95C117.3 mbar and then at 150CtO.13 mbar, affording as residue 68.86 g of a yellowish liquid product.
W spectrum (in CHCl3): ~max = 385 ~; = 6750 elemental analysis: S cal. 5.02 %; found 4.91 %.
The follo~ing compounds are prepared ln analogous manner:
a) Polyethylene glycol 300 monoester of thioxanthone-l-carboxylic Yellowish liquid product.
UV spect-um (in CHC13): ~max ~ 386 nm; = 6750 elemental analysls: S cal. 5.96 %; found 5.89 %.
~33~i b) Polyethylene ~lycol 1000 monoester o~ thioxanthone-l-carboxylic acid (n ~ 22) Yellowlsh wax-like liquid product.
W spectrum (in CHC13): ~max ~ 385 nm; E = 6600 elemental analysis: S cal. 2.61 %; found 2.59 %.
Example 2: _olypropylene glycol 400 monoester of thioxanthone-l-carboxylic acid (n ~ 7) The preparation is in accordance with Example 1 using polypropyleDe glycol 400 (avallable from Fluka, average molecular weight:
380-420). After 1 hour OD a water trap, the solution i5 stirred with potassium carboDate and alumina and filtered. The mother liquor is concentrated by evaporation, finally at 150C/0.04 mbar. The residue i3 a yellowish oil.
UV 9pectrum ~in CHc13) ~max ~ 384 nm; ~ 8 6800 elemental analysis: S cal. 5.03 %; found 5.10 %.
Example 3: Polyethylene glycol 400 diester of thioxanthone-l-carbox-yllc acid (n ~ 9) 25.63 g ~100 mM) of thioxanthone-l-carboxylic acid, 20.00 g (50 mM) of polyethylene glycol 400 (available from Fluka), 180 ml of o-dichlorobenzene and 128 mg of concentrated sulfuric acid are heated for 2 hour~ to reflux while separating water. Wor~ing up in accordance with Example I yield3 46.79 g of a yellowish viscous oil.
UV 8pectrum (in CHC13): ~max ~ 386 nm; ~ ~ 13250 elemental analysis: S : cal. 7.32 %; found 7.32 %.
xample 4: Polyeth~lene ~lycol 400 monoester of thioxanthone 1-carboxylic acid (n ~ 9) 20 g (78 mM) of thioxanthone-3-carboxylic acid~ 31.2 g (78 m~l) of polyethylene glycol 400 (available Erom Fluka), 200 ml oE
o-dichloroben?.ene and 400 mg of tetrabutylorthotitanate are kept under reflux for 7 hours while separating water. After it has cooled, the solution is stirred with 40 g of anhydrous potassium cnrbonate asld the precipitate ~8 removed by filtratlon. The mother liquor is concentrated by evaporation, Einally at 150C/0.4 mbar.
' :' 3~
The residue 19 stirred overnight in toluene/cyclohexane. The precipitate is romoved by filtration and the mother liquor i8 evaporated to dryness, affordi~g 33.12 g of a yello~ liquid product.
UV spectrum ~in CHCl3): ~max - 400 nm; ~ 6200-Example S: Polyethylene glYCol 300 monoester of 7-methylthioxanthone-3-carboxylic acid (n ~ 7~
15 g (55.2 mM) of 7-methylthioxanthone~3-carboxylic acid and 70 ml of thionyl chloride are kept at reflux for 3 hours. The mixture i9 evaporated to dryness and the residue is refluxed for 3 hours together with 140 ml of toluene and 16.S g (55.24 mM) of polyethyl-ene glycol 300 (avallable from Fluka). After it has cooled, the ~olution is stirred with anhydrou~ potassium carbonate, filtered, and the filtrate is concentrated. The partially crystalllne re~idue is stirred ln toluene/cyclohexane for 4 days at 25C, the precipi-tate is isolated by filtratlon, and the mother liquor i8 concen-trated by evaporation, affording 15.4 g of a yellow liquid product.
UV spectrum (in CHC13): ~max = 409 nm; - 5800 elemental analysis: S cal. 5.54 %; found 5.48 %.
The following compound~ i8 prepared in corresponding manner:
Polyethylene ~l~col lO00 monoe~ter of thioxanthone-3-carboxylic acid (n ~ 22) Yellow wax-like turbld product.
W spectrum (in CHC13): ~max ~ 400 nm; ~ = 5700 elemental analy~is: S cal. 2.52 %; found 2.S1 %.
Example 6: Polyethylene ~lycol 750 monomethyl ether-monoester of thioxanthone-l-carboxylic cid (n ~ 16) 3.0 g of (11.7 mM) of thioxanthone-1-carboxylic acid, 8.8 g (11.7 mM) of polyethylene 750 monomethyl ether (available from Fluka), lS ml oE o-dichlorobenzene and 70 mg of concentrated sulfuric acid are heated for 1 1/2 hours Bt reflux (bath temperature 200C), while separating tho water of reaction via a water trap. The mixture i~ cooled to about 100C, mixed with alumina, cooled to ~33%~;
25C, then stirred with 2.5 g of potassium carbonate and filtered.
The snother liquor is concentrated by evaporation, first at 95C/17.32 mbar and ~hen at 150Cl0.13 mbar, affording as ~esidue 8.0 g of a yell~wish liquid product.
VV spectrum (in CHC13): ~max ~ 385 nm; ~ ~ 6600 elemental analysis: S cal. 4.07 %; found 4.37 %.
The following compound is prepared in corresponding manner:
PolYethYlene ~lycol 550 monomethyl ether-monoester of thioxanthone-l-carboxylic acid (n ~ 12) 7.6 g of a yellowish liquid product.
W spectrum (in CHC13): ~max ~ 385 nm; E c 6200 elemental analysis: S cal. 4.07 %; found 4.37 %.
_ample 7 38.5 parts by weight of acrylate/urethane oligomer (Actilan AI 18) 19.2 parts by weight of N-vinylpyrrolidone 19.3 parts by weight of T102 (RTC-2) 19.2 parts by wei~ht of ~n5 (Sachtholith HDS) 3.8 parts by weight of butyl acPtate are mlxed with 1 % by weight of thioxanthone (based on the total ingredients) and the mixture i~ applied electromotorically with a 30 ~ doctor blade as fllm to a glass plate and dried.
UV curing of the film is effected with a standard ~ercury vapour lamp (QC proces~or, RPC) (see Table 1) or (see l'able 2) with an electrodeless mercury vapour lasnp (Type D, Fusion System Inc.). The glass plate~ are passed under the la~ps at a speed of 10 m/min.
The results are reported in Tables 1 and 2. YI ~ Yellowness Inde~.
33~
~ _ ~ _ a ~ ~ ; a ~ o ~
~ . .. ~
~ ~ o ~O ~ ~_ ~ ~ n ~ _. ~ .' ~ a a~
u ~ ~ ~o X ~ ~
':~d 3 ca~ _. ~ .. ~
,~ ~ ~ u~
a . . ~ ~ ~
~ ~3 ~ 3 ~. v . _ ,~
3~5;
Exam,ole 8: 100 parts by welght of a 55 % aqueous dispersion of an unsaturated polyester resin (ROSKYDAL W 850, availabl~ from Bayer AG) are mixed with 0.25 parts by weight of the thioxanthone-carboxylate of Example 1 and 1O5 parts by welght of N-methyldl-ethanolamlne. The mixture i8 then applied electromotorically with a 200 ~ doctor blade as a film to a glass plate. The film is cured by irradiation with a standard mercury vapour lamp in a QC processor.
The glass plate is passed under the lamp at a speed of 10 ~/min.
The film is wipe-resltant after 8 passages. The surface of the film is smooth and unlform. If isopropylthioxanthone is substituted for the thioxanthonecarboxylate in the same mixture, then the surface of the film becomes lrregular. Pits and specks as well as many pin-pricks are observed.
3-14996/+/ZFO
Liquid thioxanthonecarboxylic acid e~ters The present lnventlon relates to liquid thioxanthonecarboxylic acid ssters which contain polyoxaalkylene radicals in th~ ester group, to mlxtures of such esters with an organic amine or with a radical or cationic photoinitiator, and also to photopolymerisable systems that contain such mixtures.
Alkylthioxant`hone~ are disclosed as photoinitlators for UV curable resin systems in German Offenlegungsschrift 32 28 371. They are obtalned in liquid form and can therefore be dispersed in prepolymer formulations. These alkylthioxanthone~ have not gained acceptance for toxicologlcal reasons.
Thioxanthonecarboxylic acid esters are disclosed as photoiDitiators in German Offenlegungsschrlft 30 lS 891. Among the crystalline compounds, mention is also made of the ester of triethylene glycol monomethyl ether and thioxanthone-1-carboxylic acid, said ester being in the form of an oilO It has subsequently been found that this compound crystallise6 after a tim0. In addition to an in-sufficient ~helf-life, this crystallisation constitutes a furth~r substantial disadvantage for the production of this compound. Seed crystals formed during production can no longer be removed from the apparatus, which may result in crystallisation of the desired liquid compounds and thus in dlscontinuation of production.
D~
33~
Thloxanthonecarboxylic acld eaters containing functional eater groups are deacribed in European publiahed patent applica-tion 0 033 720. Ihe diethylene and triethylene glycol asters of 7-methylthioxanthone-3-carboxylic acid referred to in thls publi-cation are solid compounds.
Liquid thioxanthones can be more readlly incorporated and dispersed in syatems which can be cured by irradiation. In addition, those thioxanthones are de3irable whlch can be disperaed or emulsified in liquid, eapecially aqueous, coating composition~.
Specifically, the present invention relates to liquid thioxanthone-carboxylic acid esters and liquid mixtures of thioxanthonecarbo~ylic acid ester~ of the formula I
~ ~CO-(OR) - ORl Y~ /il\ /il 4 ~ (I) wherein X is hydrogen, halogen, NO2, COOH, unsubstituted or alkyl-sub-stituted amlno, Cl-Czoalkyl, Cl-C2Galkoxy, Cl-C20alkylthio, Cl-C20alkylsulfoxyl, Cl-C2Dalkylaulfonyl, unsub~tituted or sub~tltuted phenoxy, phenylthio, phenylsulfoxyl or phenyl-sulfonyl, or i~ -COOR , wherein R i9 alkyl, cycloalkyl, aryl, alkaryl, aralkyl, alkaralkyl, hydroxyalkyl, alkoxyalkyl or free or othesifi~d polyoxaalkyl, Y ha~ in each caa~ independently the same meaning aa X, n is an integer from 4 to 2S, R ig linear or branched C2-C6alkylene, and R~ la hydrogen, alkyl or a radical of the formula II
~L~k33 CO
o S \- ~ (II) with the proviso that, if R is ethylene and Rl is hydrogen, n is an int~ger from 7 to 25 and, if R i9 ethylene and Rl 1~ methyl, n is an integer from 11 to 25.
Among the mlxtures, those whlch compounds of fonnula I are pre-ferred, whereln n has different value~, or mixtures of thos~
compounds of formula I, wherein Rl is, on the one hand, hydrogen and, on the other, 15 a radical of formula II, whlch mlxtures may addltionally contain compound~ of for~ula I in which n has different values.
X and Y a~ halogen are preferably bromine and, most preferably, chlorine or fluorine. X and Y as unsubstituted or alkyl-substituted amlno may be -NH2, -NHR2 or ~NR2, wherein R2 i~ l~near or branched alkyl of preferably 1 to 6 carbon atoms, phenyl, benzyl, cyclopentyl or cyclohexyl. Al~yl is for example methyl, ethyl, ~-propyl, lsopropyl, butyl, pentyl and hexyl.
X and Y es alkyl, and the alkyl molety of alkoxy, alkylthlo, alkylsulfoxyl and alkylsulfonyl groups X and Y, may be llnear or branched and preferably contain l to 12, in particular l to 6 and, most prefe~ably, 1 to 4 carbon atom~. Examples of such alkyl groups are: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, undecyl and dodscyl. X and Y a~. alkyl are preferably methyl~
Suitable substituentR of th~ phsnoxy, phenylthio, phonylsulfonyl and phenylsulfoxyl groups are, for example, Cl-C4alkyl and halogen such as fluorine, chlorine or bromine.
æ~
Ra as alkyl contains preferably 1 to 6 carbon atoms and is, in particular, methyl or ethyl. Ra as cycloalkyl is preferably cyclo-pentyl and cyclohexyl. Ra as aryl i~ preferably phenyl and, as alkaryl, is preferably alkylphenyl containing 1 to 4 carbon atoms 1n the alkyl moiety. Ra as aralkyl is preEerably benzyl and, as alkaralkyl, ls preferably alkylbenzyl containing 1 to 4 carbon atoms in the alkyl moiety. Ra as hydroxyalkyl may be linear or branched and contalns preferably 2 to 6 carbon atoms. Ra as alkoxyalkyl preferably contains 3 to 12 carbon atoms and has in particular the formula -CXH2x-oR3, wherein x is an integer from 2 to 6, preferably from 2 to 4, and R3 is preferably C1-C~Oalkyl. Ra as free or etherified polyoxa~lkyl preferably has the formula -(CxH2xo)y~R4, wherein x is an integer from 2 to 6, preferably 2 to 4, and y is an integer from 2 to 25, preferably from 2 to 18 and, most preferably, from 2 to 12, and R4 i5 hydrogen or C1-C12alkyl, preferably C1-C6alkyl. Most preferably, R4 i8 hydrogen, methyl or ethyl.
X is preferably hydrogen. The radical Y is preferably bonded in the 7-posltion. In a preferred embodiment, Y is hydrogen or C1-C6alkyl 7 preferably methyl.
The -CO-(OR)n-OR1 group is preferably bonded in the 1- or 3-position.
R as alkylena i9 for example ethylene, 1,2- and 1,3-propylene, 1,2-, 1,3 and 1,4-butylene, 1,2-, 1,3-, 1,4- and 1,5-pentylene, and 1,2-, 1,3-, 1,4-, 1,5 and 1,6-hexylene. R i8 preEerably C2-CI,alkylene, most preferably ethylene, 1,2- or 1,3-propylene.
Rl as alkyl may be linear or branched and preferably contains 1 to 12, most preferably 1 to ~, carbon atoms. Examples of alkyl groups are those mentioned above for X. In a preferred embodiment, Rl is hydrogen, methyl, ethyl or a radlcal of the formula II.
~2~33~5 If R iB linear alkylene, n is preferably an integer from 9 to 25 and, if R i3 branched alkylenP, n is preferably an integer from 6 to 25.
In a prefsrred embodiment, n is an integer from 8 to 20, preferably from 8 to 18, most preferably from 8 to 14, if Rl is hydrogen or a radical of formula II. In another preferred embodiment, n i9 an integer from 11 to 20, most preferably from 12 to 18, lf Rl i~
aikyl.
In a particularly preferred subgroup, R i3 ethylene, Rl i9 hydrogen or a radical of formula II and n i3 an integer from 8 to 14, or R ls ethylene, R1 is methyl and n i8 an integer from 12 to 18.
The compounds of formula I and mixtures thereof are obtained by coDventional esterification procedure3 by reactlng thioxanthone-carboxyllc acids of formula ~ COOH
Y~ 11 1 ~X
S
or ester-forming derivatives thereof, e.g. acid esters or acid halides, with alcohols of formula Rs O-(RO)D H~
~herein Rs is hydrogen or alkyl. The reaction may be carried out in the presence of an inert organic solvent and at elavated tempera-ture, for example in the range from 50 to 200C. Examples of suitable inert 601vents are aromatic hydrocarbons such as benzene, toluene, xylene, chlorobenzene and 1,2 dichloroben7ene.
~Z~33~
In the esterification of the carboxylic acids or transPsterification of carboxylic acid esters, acids or metal compounds can be us2d as catalysts, for example hydrochloric acid, sulfuric acid and 3ulfonic acids, tetraalkylorthotitanates or dialkyltin oxides.
If Rs i9 alkyl, 1 equivalent of alcohol of the formula RsO-(RO)n~H
will preferably be used. If Rs is hydrogen, 0.5 to 1 equivalent of dialcohol of the formula HO-(RO)n-H may be used. Depending on the amount added, compounds of formula I are then obtained in which R
is hydrogen or a radical of formula II9 or mixtures of such compounds .
Thioxanthonecarboxylic acids and acid derivatives are known from German Offenlegungsschrift 30 18 891 and European published patent application 0 033 720, or they can be prepared by analogous procedures. The alcohols employed are also known and some are commercially available.
The compounds of formula I and mixtures thereof are liquid to oily substances which can be readily incorporated ln substrates.
Surprisingly, they are also distinguished by the feature that they have an insignificant tendency to cause yellowing.
The compound~ of formula I and mixtures thereof can be used together with hydrogen donors, especially with organic amines, as photoini-tiators for the photopolymerisation of ethylenically unsatura~ed compounds or for the photocrosslinking of polyolefins, as well as photoredox catalysts, for example for metal deposition without current. Accordingly, the invention alao relates to mixtures of A) at least one compound of formula I and B~ at least one organic amine, as initiators for the photopolymerisation of ethylenically compounds or for the photochemical crosslinking of polyolefins.
3~
The organic amines employed may be allphatic, aro~atic, araliphatic, cycloaliphatic or heterocyclic amines. They can be primary, secondary or tertiary amines. Examples of such amines are: butyl-amine, dibu-tylamine, tributylamine, cyclohexylamine, benzyldimethyl-amine, dicyclohexylamine, triethylamine, phenyl diethanolamine, piperidine, piperazine, morpholine, pyridine, quinoline, ethyl p-dimethylaminobenzoate or Michler 18 ketone (4,4'-bisdimethylamino-benzophenone).
Examples of pre.~erred aliphatic tertiary amines are trimethylamine, triethylamine, trllsopropylamine, trlbutylamine, dodecyldimethyl-amine, octyldim~thylamine, triethanolamine, tris(hydroxypropyl~-amine, ~-methyldiethanolamine or N-butyldiethanolamine.
The mixtures of this invention preferably contain the compounds of formula I and the organic amines in a weight ratio o 4-1 to 1:4.
Photopolymerisable compounds are, for example, unsaturated monomers, such as esters of acrylic acid or methacrylic acid, for example methyl acrylate, ~thyl acrylate, n- or tert-butyl scrylate, isooctyl ~crylate or hydroxyethyl acrylate, methyl methacrylate or ethyl methacrylate, ethylene diacrylate, butanediol diacrylate, hexanediol diacrylate, r.eopentyl diacrylate, trimethylpropane trisacrylate, pentaerythritol tetraacrylate or pentaerythritol trisacrylate;
acrylonitrile, methacrylonltrile, acrylamide, methacrylamide and N-substituted acrylamides and methacrylamides; vinyl esters, for example vinyl acetate, vlnyl propionate, vinyl acrylate or vlnyl succlnate; other vinyl compounds such as vinyl ethers, vinyl ketones, vlnyl sulfones, ~tyrene, alkylstyrenes, halostyrenes, divinylbenzene, N,N'-divinylurea, vinylnaphthalene, N-vinyl~
pyrrolidone, vinyl chloride or vlnylldene chloride; allyl compounds such as diallyl phthalate, diallyl maleate, triallyl isocy~nurate, triallyl phosphate or ethylene glycol diallyl ether, and the mixtures of such unsaturated monomers.
~ ~L~ ~ 3 ~ 5 The mixtures of this invention are particularly sultable for the photopolymerisation of acrylic acid ester~ and mixtures thereof.
Further examples are unsaturated acrylic resins. These include 9 for example, reac~ion products of polyepoxides (epoxy res~ns) with acrylic acid or methacrylic acid or reaction products of polyiso-cyanates with hydroxyalkyl acrylates, and also the reactlon products of hydroxylated polyesters or polyethers with acrylic acid or methacrylic acid. These unsaturated acrylic re~ins are generally used in admixture wlth one or more acrylates of a mono-, di- or polyalcohol, for example ethyl acrylate, butyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate or 2-hydroxypropyl acrylate, ethylene glycol diacrylate, propylene glycol diacrylate, butanediol diacrylate, hexamethylene diacrylate, trimethylolpropane tris-acrylate or pentaerythritol tetraacrylate.
The invention also relates to photopolymerisable systems comprising a) at least one ethylenically unsaturated compound, b) a mixture of A) and B) as defined herein and, if desired, c) other additives, such as inhibitors, stabilisers, W-absorbers, fillers/ pigments, dyes, thixotropic agents and levelling assistants, for example silicone oil.
Examples of inhibitors which are intended to provide protection a~ain~t premature polymQrisation, in particular during the prepara-tion of the systems by mixing the components, are hydroquinone, hydroquinone derivatives, p-methoxyphenol or ~-naphthol.
W-ab~orbers which can be used are, for example, those of the benztriazole or benzophenone type. Suitable fillers are, for example, silica, talcum, gla3s fibres, titanium dioxide or gypsum.
Preferred photopolymerisable systems of this type are those in which a) and c) are present in amounts of 99.5-80 % by weight and b) is present in an amount of 0.5-20 % by weight.
33%~
g An acrylate or a mlxture of several acrylates is preferably used as component a).
In particular, the photopolymerisable systems of the present invention are coloured systems whlch contain at least one pigment or one dye. Such systems are used in particular as printlng inks and as whlte lacquers.
A further Eleld of use of the compounds of formula I is as photo-sensltizers in conjunctlon with a radical or cationic photoinl-tiator. Radical photoinitiators are those which form radicals by photofragmentation. Known classes of radlcal photoinitiators are for example ben~oin ethers, halogenated acetophenones, benzll ketals, alkoxyacetophenones, i~obutyrophenones (as described for example in European published patent application 3002, DE-OS 2 722 264 or European published patent application 88050) or acylphosphine oxides (as described for example in European published patent applica-tion 7508). Cationic photolnitiators are those which, on irradia-tion, spllt off protons or Lewis acids. Known examples of such photoinitiators are aromatic sulfonium or iodonium salts.
The combinations with radical photoiniators are used for the photopolymerisation of the ethylenically un~aturated compounds specified above. The comblnations with cationic photoinitiators are used for photopolymerising cationically polymerisable compounds.
These may be cyclic ethers or thioether~, lactones, lactams or also specific vinyl compounds. Combinations with cationic photoinitiators are of particular importance for the ra~iation curing of epoxy resins.
The initiator mixtures according to the invention are of great importance for the photocuring of printing inks and white-pigmented coatings, as the drying time of the binder is a decisive factor in the production rate of printing yroducts and should be of ~33~;
the order oE magnltude of fractlons of a second. The initiators of the invention are also very suitable for photocurable systems for the production of prlnting plates.
A further fleld of application ls the UV curing of metal coatings, for example in the vanlsh coating of sheet metal for tubes, cans or bottle top3, and also the W curing of plastic coatings, for example floor coverlngs or wall coverings based on PVC.
Examples of the W curing oE paper coatings are the colourless varnish coating of labels, gramophone record sleQve3 or book ~ackets.
The mixtures of this invention can also be used as initiators for photochemical crossllnklng of polyolefins. Polyolefins which can be used are, for example, polypropylene, polybutylene, polyiso-butylene and copolymers, for example ethylene/propylene copolym2rs~
but preferably polyethylene of low, moderate or high density.
The addition of the preferred photoinitiators to the photopoly-~erisable systems is generally effected by simple stirring, as most of these systems are llquid or readily soluble. A solution of the initlators is obtained, ther~by ens~ring thelr uniform distribution and the transparency of the polymers.
The polymerisation is effected by the known methods of photopoly-merisation by lrradlation with light which is rich in short-wave radiation. Suitable light sources are, for example, medium pressure, high pressure and low pressure mercury lamps7 and ~150 superactinic fluorescent tubes, the emission peaks oE which are in the range from 250 to 450 nm.
For the photochemlcal crosslinking of polyoleEins, the photoiniator i~ added to the polyolefin before or during processing to ~haped articles. Crosslinking is effected by irradiating the shaped article in solid form, or example in the Eorm of sheets or f:Llaments.
33%~
The compounds of formula I are al~o suitable for use as sensitizers for photocrosslinka'ole polymers of the most widely different kind.
Such polymers are used, for example, for preparing photographlc offset varnlshes for unconventional photography, for example for obtaining photographic images by photopolymerisation or photocross-linking. Such polymers are used in particular as photoresists for making printed circuit~ by methods which are known per se. This i3 done by exposing the side of the printed circuit board containing the light-sensitive layer with a negatlve transparency of the conductive pattern and then developing it by dis~olving out the unexposed areas of the layer with developing fluid.
The polymers employed may be any materials whose light sensitivity (sensitivity to actinic rsdiation) can be enhanced by the use of the compounds of formula I. The compounds of formula I are most parti-cularly suitable for use as sensiti~ers for the polymers disclosed 1n DE-OS 26 26 769, the light-sensitive groups of which have the formula ,Q ,Gl \-/ \G
a 2 wherein Gl and G2 are each independently of the other Cl-C4alkyl, preferably methyl, or Gl and G2, when taken together, complete a 5-or 6-membered carbocyclic ring.
The compounds of formula I can be incorporated in the photocrossllnk-abla polymers in a manner known per se. The amount of compounds of formula I in the polymer can vary greatly, depending on the end use and on the number of photocrosslinkable groups present in the polymer, but is usually from about O.l ~o 20 % by weight, based on the weight of the mixture.
~2~3~
The compounds of fDrmula I of the present inventlon are particularly suitable for aqu~ous coating compositions which can be cured by irradiatlon, as they can be readily emulsified and dlstrlbuted because of their llquid character. An even distribution in a produced layer iB al90 thereby achleved. After lrradiating such a layer, a more level curing is also achieved.
The following Examples illustrata the invention ln more detail.
Example 1: Polyethylene ~1YCO1 400 monoester of thioxanthone~l-carboxylic acid (n ~ 9) 25.63 g (100 mM) of thioxanthone-1-carboxylic acid, 40.00 g (100 mM) of polyethylene glyrol 400 (available from Fluka, average ~olecular weight: 380-420), 150 ml of o-dichlorobenzene and 138 mg of concentrated sulfurlc acld are heated to reflux for 35 minutes (bath temperature 200C), while separatlng off the water of reactlon vla 8 water trap. After it has cooled, the solutlon ls stirred wlth anhydrous potassium carbonate and then filtered. The mother liqusr ls concentrated by evaporation, flrst at 95C117.3 mbar and then at 150CtO.13 mbar, affording as residue 68.86 g of a yellowish liquid product.
W spectrum (in CHCl3): ~max = 385 ~; = 6750 elemental analysis: S cal. 5.02 %; found 4.91 %.
The follo~ing compounds are prepared ln analogous manner:
a) Polyethylene glycol 300 monoester of thioxanthone-l-carboxylic Yellowish liquid product.
UV spect-um (in CHC13): ~max ~ 386 nm; = 6750 elemental analysls: S cal. 5.96 %; found 5.89 %.
~33~i b) Polyethylene ~lycol 1000 monoester o~ thioxanthone-l-carboxylic acid (n ~ 22) Yellowlsh wax-like liquid product.
W spectrum (in CHC13): ~max ~ 385 nm; E = 6600 elemental analysis: S cal. 2.61 %; found 2.59 %.
Example 2: _olypropylene glycol 400 monoester of thioxanthone-l-carboxylic acid (n ~ 7) The preparation is in accordance with Example 1 using polypropyleDe glycol 400 (avallable from Fluka, average molecular weight:
380-420). After 1 hour OD a water trap, the solution i5 stirred with potassium carboDate and alumina and filtered. The mother liquor is concentrated by evaporation, finally at 150C/0.04 mbar. The residue i3 a yellowish oil.
UV 9pectrum ~in CHc13) ~max ~ 384 nm; ~ 8 6800 elemental analysis: S cal. 5.03 %; found 5.10 %.
Example 3: Polyethylene glycol 400 diester of thioxanthone-l-carbox-yllc acid (n ~ 9) 25.63 g ~100 mM) of thioxanthone-l-carboxylic acid, 20.00 g (50 mM) of polyethylene glycol 400 (available from Fluka), 180 ml of o-dichlorobenzene and 128 mg of concentrated sulfuric acid are heated for 2 hour~ to reflux while separating water. Wor~ing up in accordance with Example I yield3 46.79 g of a yellowish viscous oil.
UV 8pectrum (in CHC13): ~max ~ 386 nm; ~ ~ 13250 elemental analysis: S : cal. 7.32 %; found 7.32 %.
xample 4: Polyeth~lene ~lycol 400 monoester of thioxanthone 1-carboxylic acid (n ~ 9) 20 g (78 mM) of thioxanthone-3-carboxylic acid~ 31.2 g (78 m~l) of polyethylene glycol 400 (available Erom Fluka), 200 ml oE
o-dichloroben?.ene and 400 mg of tetrabutylorthotitanate are kept under reflux for 7 hours while separating water. After it has cooled, the solution is stirred with 40 g of anhydrous potassium cnrbonate asld the precipitate ~8 removed by filtratlon. The mother liquor is concentrated by evaporation, Einally at 150C/0.4 mbar.
' :' 3~
The residue 19 stirred overnight in toluene/cyclohexane. The precipitate is romoved by filtration and the mother liquor i8 evaporated to dryness, affordi~g 33.12 g of a yello~ liquid product.
UV spectrum ~in CHCl3): ~max - 400 nm; ~ 6200-Example S: Polyethylene glYCol 300 monoester of 7-methylthioxanthone-3-carboxylic acid (n ~ 7~
15 g (55.2 mM) of 7-methylthioxanthone~3-carboxylic acid and 70 ml of thionyl chloride are kept at reflux for 3 hours. The mixture i9 evaporated to dryness and the residue is refluxed for 3 hours together with 140 ml of toluene and 16.S g (55.24 mM) of polyethyl-ene glycol 300 (avallable from Fluka). After it has cooled, the ~olution is stirred with anhydrou~ potassium carbonate, filtered, and the filtrate is concentrated. The partially crystalllne re~idue is stirred ln toluene/cyclohexane for 4 days at 25C, the precipi-tate is isolated by filtratlon, and the mother liquor i8 concen-trated by evaporation, affording 15.4 g of a yellow liquid product.
UV spectrum (in CHC13): ~max = 409 nm; - 5800 elemental analysis: S cal. 5.54 %; found 5.48 %.
The following compound~ i8 prepared in corresponding manner:
Polyethylene ~l~col lO00 monoe~ter of thioxanthone-3-carboxylic acid (n ~ 22) Yellow wax-like turbld product.
W spectrum (in CHC13): ~max ~ 400 nm; ~ = 5700 elemental analy~is: S cal. 2.52 %; found 2.S1 %.
Example 6: Polyethylene ~lycol 750 monomethyl ether-monoester of thioxanthone-l-carboxylic cid (n ~ 16) 3.0 g of (11.7 mM) of thioxanthone-1-carboxylic acid, 8.8 g (11.7 mM) of polyethylene 750 monomethyl ether (available from Fluka), lS ml oE o-dichlorobenzene and 70 mg of concentrated sulfuric acid are heated for 1 1/2 hours Bt reflux (bath temperature 200C), while separating tho water of reaction via a water trap. The mixture i~ cooled to about 100C, mixed with alumina, cooled to ~33%~;
25C, then stirred with 2.5 g of potassium carbonate and filtered.
The snother liquor is concentrated by evaporation, first at 95C/17.32 mbar and ~hen at 150Cl0.13 mbar, affording as ~esidue 8.0 g of a yell~wish liquid product.
VV spectrum (in CHC13): ~max ~ 385 nm; ~ ~ 6600 elemental analysis: S cal. 4.07 %; found 4.37 %.
The following compound is prepared in corresponding manner:
PolYethYlene ~lycol 550 monomethyl ether-monoester of thioxanthone-l-carboxylic acid (n ~ 12) 7.6 g of a yellowish liquid product.
W spectrum (in CHC13): ~max ~ 385 nm; E c 6200 elemental analysis: S cal. 4.07 %; found 4.37 %.
_ample 7 38.5 parts by weight of acrylate/urethane oligomer (Actilan AI 18) 19.2 parts by weight of N-vinylpyrrolidone 19.3 parts by weight of T102 (RTC-2) 19.2 parts by wei~ht of ~n5 (Sachtholith HDS) 3.8 parts by weight of butyl acPtate are mlxed with 1 % by weight of thioxanthone (based on the total ingredients) and the mixture i~ applied electromotorically with a 30 ~ doctor blade as fllm to a glass plate and dried.
UV curing of the film is effected with a standard ~ercury vapour lamp (QC proces~or, RPC) (see Table 1) or (see l'able 2) with an electrodeless mercury vapour lasnp (Type D, Fusion System Inc.). The glass plate~ are passed under the la~ps at a speed of 10 m/min.
The results are reported in Tables 1 and 2. YI ~ Yellowness Inde~.
33~
~ _ ~ _ a ~ ~ ; a ~ o ~
~ . .. ~
~ ~ o ~O ~ ~_ ~ ~ n ~ _. ~ .' ~ a a~
u ~ ~ ~o X ~ ~
':~d 3 ca~ _. ~ .. ~
,~ ~ ~ u~
a . . ~ ~ ~
~ ~3 ~ 3 ~. v . _ ,~
3~5;
Exam,ole 8: 100 parts by welght of a 55 % aqueous dispersion of an unsaturated polyester resin (ROSKYDAL W 850, availabl~ from Bayer AG) are mixed with 0.25 parts by weight of the thioxanthone-carboxylate of Example 1 and 1O5 parts by welght of N-methyldl-ethanolamlne. The mixture i8 then applied electromotorically with a 200 ~ doctor blade as a film to a glass plate. The film is cured by irradiation with a standard mercury vapour lamp in a QC processor.
The glass plate is passed under the lamp at a speed of 10 ~/min.
The film is wipe-resltant after 8 passages. The surface of the film is smooth and unlform. If isopropylthioxanthone is substituted for the thioxanthonecarboxylate in the same mixture, then the surface of the film becomes lrregular. Pits and specks as well as many pin-pricks are observed.
Claims (23)
1. A liquid thioxanthonecarboxylic acid ester or a liquid mixture of thioxanthonecarboxylic acid esters of the formula I
(I) wherein X is hydrogen, halogen, NO2, COOH, unsubstituted or alkyl-sub-stituted amino, C1-C20alkyl, C1-C20alkoxy, C1-C20alkylthio, C1-C20alkylsulfoxyl, C1-C20alkylsulfonyl, unsubstituted or substituted phenoxy, phenylthio, phenylsulfoxyl or phenyl-sulfonyl wherein the substituents are chosen from C1-C4alkyl or halogen or is -COORa, wherein Ra is alkyl, cycloalkyl, aryl, alkaryl, aralkyl, alkaralkyl, hydroxyalkyl, alkoxyalkyl or free or etherified polyoxaalkyl of the formula -(CxH2xO)y-R4, in which X is an integer from 2 to 6, y is an integer from 2 to 25, and R9 is hydrogen or C1-C12alkyl.
Y has in each case independently the same meaning as X, n is an integer from 4 to 25, R is linear or branched C2-C6alkylene, and R1 is hydrogen, alkyl or a radical of the formula II
(II) with the proviso that, if R is ethylene and R1 is hydrogen, n is an integer from 7 to 25 and, if R is ethylene and R1 is methyl, n is an integer from 11 to 25.
(I) wherein X is hydrogen, halogen, NO2, COOH, unsubstituted or alkyl-sub-stituted amino, C1-C20alkyl, C1-C20alkoxy, C1-C20alkylthio, C1-C20alkylsulfoxyl, C1-C20alkylsulfonyl, unsubstituted or substituted phenoxy, phenylthio, phenylsulfoxyl or phenyl-sulfonyl wherein the substituents are chosen from C1-C4alkyl or halogen or is -COORa, wherein Ra is alkyl, cycloalkyl, aryl, alkaryl, aralkyl, alkaralkyl, hydroxyalkyl, alkoxyalkyl or free or etherified polyoxaalkyl of the formula -(CxH2xO)y-R4, in which X is an integer from 2 to 6, y is an integer from 2 to 25, and R9 is hydrogen or C1-C12alkyl.
Y has in each case independently the same meaning as X, n is an integer from 4 to 25, R is linear or branched C2-C6alkylene, and R1 is hydrogen, alkyl or a radical of the formula II
(II) with the proviso that, if R is ethylene and R1 is hydrogen, n is an integer from 7 to 25 and, if R is ethylene and R1 is methyl, n is an integer from 11 to 25.
2. An ester or mixture of esters according to claim 1, wherein X is hydrogen.
3. An ester or mixture of esters according to claim 1, wherein Y is hydrogen or C1-C6 alkyl.
4. An ester or mixture of esters according to claim 1, wherein R is C2-C4alkylene.
5. An ester or mixture of esters according to claim 4, wherein R is ethylene, 1,2- or 1,3-propylene.
6. An ester or mixture of esters according to claim 1, wherein R1 is C1-C6alkyl.
7. An ester or mixture of esters according to claim 1, wherein R1 is hydrogen, methyl or ethyl.
8. An ester or mixture of esters according to claim 1, wherein R1 is a radical of formula II.
9. An ester or mixture of esters according to claim 1, wherein Y is bonded in the 7-position.
10. An ester or mixture of esters according to claim 1, wherein the -CO-(OR) -OR1 group is bonded in the 1- or 3-position.
11. An ester or mixture of esters according to claim 1, wherein n is an integer from 8 to 20, if R1 is hydrogen or a radical of for-mula II, or n is an integer from 11 to 20, if R1 is alkyl.
12. An ester or mixture of esters according to claim 1, wherein R is ethylene, R1 is hydrogen or a radical of formula II and n is an integer from 8 to 14, or R is ethylene and R1 is methyl and n is an integer from 12 to 18.
13. An ester or mixture of esters according to claim 11 wherein n is an integer from 8 to 14, if R1 is hydrogen or a radical of formula II, or n is an integer from 12 to 18, if R1 is alkyl.
14. A mixture comprising A) at least one compound of formula I according to claim 1 and B) at least one primary, secondary or tertiary aliphatic, aromatic, araliphatic, cycloaliphatic, or heterocyclic amine,
15. A photopolymerisable system containing a) at least one photopolymerisable ethylenieally unsaturated compound, b) a mixture according to claim 14 and, if appropriate, c) other additives.
16. A coloured photopolymerisable system according to claim 15, which contains at least one pigment or dye.
17. A mixture comprising A) at least one compound of formula I according to claim 1 and B) a radical photoinitiator.
18. A photopolymerisable system containing a) at least one photopolymerisable ethylenically unsaturated compound, b) a mixture according to claim 17,
19. A mixture comprising A) at least one compound of formula I according to claim 1 and B) a catlonic photoinitiator.
20. A photopolymerisable system containing a) at least one epoxy resin b) a mixture according to claim 19.
21. A mixture comprising A) a photocrosslinkable polymer and B) at least one compound of formula I according to claim 1.
22. A mixture according to claim 21, which contains 0.1 to 20 % by weight of component B.
23. A photopolymerisable system according to claim 15, which is an aqueous coating composition.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH322884 | 1984-07-04 | ||
| CH3228/84-1 | 1984-07-04 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1243325A true CA1243325A (en) | 1988-10-18 |
Family
ID=4251411
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000484563A Expired CA1243325A (en) | 1984-07-04 | 1985-06-20 | Liquid thioxanthonecarboxylic acid esters |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0167489B1 (en) |
| JP (1) | JPS6134057A (en) |
| CA (1) | CA1243325A (en) |
| DE (1) | DE3567866D1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2454579A (en) * | 2007-11-09 | 2009-05-13 | Lambson Ltd | Photoinitiator and method of manufacture |
| CN106810627A (en) * | 2015-12-02 | 2017-06-09 | 天津久日新材料股份有限公司 | UV-LED light sources compounding light trigger |
| WO2019001268A1 (en) * | 2017-06-29 | 2019-01-03 | 北京键凯科技股份有限公司 | Pegylated thioxanthone photoinitiator and photosensitive resin composition |
| US11174239B2 (en) | 2017-06-29 | 2021-11-16 | Jenkem Technology Co., Ltd. (Beijing) | PEGylated thioxanthone photoinitiator and photosensitive resin composition |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH062612B2 (en) * | 1985-07-25 | 1994-01-12 | 日本化薬株式会社 | Low temperature curing method for resin mortar or resin concrete composition |
| GB2396153A (en) * | 2002-12-12 | 2004-06-16 | Sun Chemical Bv | Sulfonium salts useful as cationic photoinitiators in energy-curable compositions and processes of preparing cured polymeric compositions |
| CN100360518C (en) * | 2004-12-20 | 2008-01-09 | 天津久日化学工业有限公司 | Light mitiator of thioxanthone-2-carboxylic ester |
| CN101906095B (en) * | 2010-07-06 | 2013-08-14 | 天津久日化学股份有限公司 | Thioxathone-4-carboxylic ester and preparation method as well as photoinitiator composition and application |
| IT1402691B1 (en) * | 2010-11-10 | 2013-09-13 | Lamberti Spa | LOW MIGRABILITY THIOXANTONS |
| CN108084335B (en) * | 2016-11-21 | 2020-10-23 | 中国石油化工股份有限公司 | Composition with polymerization initiating function and method for preparing acrylamide copolymer |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4348530A (en) * | 1980-02-05 | 1982-09-07 | Ciba-Geigy Corporation | Thioxanthonecarboxylic acids, esters, thioesters and amides with reactive functional groups |
-
1985
- 1985-06-20 CA CA000484563A patent/CA1243325A/en not_active Expired
- 1985-06-28 DE DE8585810300T patent/DE3567866D1/en not_active Expired
- 1985-06-28 EP EP19850810300 patent/EP0167489B1/en not_active Expired
- 1985-07-04 JP JP14593285A patent/JPS6134057A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2454579A (en) * | 2007-11-09 | 2009-05-13 | Lambson Ltd | Photoinitiator and method of manufacture |
| GB2454579B (en) * | 2007-11-09 | 2012-06-13 | Lambson Ltd | Photoinitiators |
| CN106810627A (en) * | 2015-12-02 | 2017-06-09 | 天津久日新材料股份有限公司 | UV-LED light sources compounding light trigger |
| CN106810627B (en) * | 2015-12-02 | 2019-03-01 | 天津久日新材料股份有限公司 | UV-LED light source compounding photoinitiator |
| WO2019001268A1 (en) * | 2017-06-29 | 2019-01-03 | 北京键凯科技股份有限公司 | Pegylated thioxanthone photoinitiator and photosensitive resin composition |
| US11174239B2 (en) | 2017-06-29 | 2021-11-16 | Jenkem Technology Co., Ltd. (Beijing) | PEGylated thioxanthone photoinitiator and photosensitive resin composition |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6134057A (en) | 1986-02-18 |
| DE3567866D1 (en) | 1989-03-02 |
| EP0167489A2 (en) | 1986-01-08 |
| EP0167489B1 (en) | 1989-01-25 |
| EP0167489A3 (en) | 1986-12-03 |
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