CA1234242A

CA1234242A - Sensitizers for photopolymerisation

Info

Publication number: CA1234242A
Application number: CA000318328A
Authority: CA
Inventors: Louis Felder; Rudolf Kirchmayr; Rinaldo Husler
Original assignee: Ciba Geigy Investments Ltd
Current assignee: BASF Schweiz AG
Priority date: 1977-12-22
Filing date: 1978-12-20
Publication date: 1988-03-15
Also published as: JPH0248536B2; DD141320A5; PL212042A1; JPS5499185A; SU948300A3; US4308400A; JPH0257081B2; GR71655B; PL117576B1; HU181680B; JPH01139554A; FI64169C; US4318791A; US4321118A; JPH0134242B2; DK576278A; AR226169A1; AU529495B2; EP0003002B1; DK157083C

Abstract

SENSITIZERS FOR PHOTOPOLYMERISATION

Abstract of the Disclosure Aromatic-aliphatic kittens of the formulae I, II, III or IV

I
III
IV

wherein n is 1 or 2, Ar is an aryl radical, R1 and R2 are monovalent aliphatic, cycloaliphatic or araliphatic radi-cals, R3 is a direct bond or a divalent organic radical, X is a hydroxyl or amino group or the monovalent etherifi-cation or silylation products thereof, and X' is a divalent amino, ether or silyloxy group, Y is a direct bond or CH2 and Z is O, S, SO2, CH2 or C(CH3)2, are suitable sensitizers for the photopolymerisation of unsaturated compounds and for the photochemical crosslinking of polyolefins. Some of these compounds are novel and can be obtained by methods analogous to those for obtaining the known compounds of this type.

Description

I

Sensitizers for photopolymerisation The invention relates to the use of aromatic aliphatic kittens which are substituted in the a-position as sensitizers for the photopolymerisation of unsaturated compounds or for the photo chemical cross linking of polyp olefins, as well as to the photopolymerisable and cross-likable systems which contain such sensitizers.

Photo chemical polymerization processes have attained substantial importance in the art, especially in whose cases where thin layers have to be hardened in a short time, for example in the hardening of varnish coat-ins or in the drying of printing inks. Compared with con-ventional hardening methods, W irradiation in the presence of photosensitizes has a number of advantages, the most important of which is the great speed of the photo hardening.
The speed is heavily dependent on the photosensiLizer em plowed and there has been no lack of attempts to replace the conventional sensitizers by ever better and more effect live compounds. Among the most effective photosensitizes are derivatives of Bunsen, in particular the Bunsen described for example in German patent specification - I.. ......... .. .. .

~23~2~

1,694,149, derivatives of a~hydroxymethylbenzoin described in German Offenlegungsschrift 1,923,266, and the dialkoxy-acetophenones and bouncily monoketals described for example in German Offenlegungsschrift 2,261,383 or 2,232,365.
Aminoacetophenones and ~-diaminoacetophenones have no-gently been proposed as photosensitizes in US patent specie cation 4,048,03~ and a-hydroxy-a-alkylolacetophenoneS and their ethers in German Offenlegungsschrift 2,357,866. The shortcomings of these known photosensitizes are in some cases an insufficient storage life in the dark of the photo-polymerisable systems mixed with such sensitizers. A number of Bunsen derivatives tend to cause yellowing of the her-dined compositions. Other sensitizers are insufficiently react live - a feature which is observed in the relatively lengthy hardening times - or their volubility in the photopolymeri-sable systems is too low or they are rapidly rendered in-active by atmospheric oxygen. There is therefore a need in the art for photosensitizes which are readily soluble in the substrate and, while having a good storage life in the dark, initiate the photopolymerisation more rapidly and give a higher polymer yield per unit of time than the known photosensitizes. By using such improved photosensitizes it would be possibly to exploit better the expensive in-dustrial US irradiation plants.

It has been found that compounds of the follow-in formulae I, II, III and IV possess the required proper-ties as photosensitizes. In particular, they effect a rapid photopolymerisation Andy not have the shortcomings referred to or possess them to a much lesser degree than the known photosensitizes. Furthermore, they are suitable for the photo chemical cross linking of polyolefins. The invention relates to the use of the compounds of the for-mule I, II, III or IV

" .~, I

~Z~34~

O R
r 11 An - C C X
lo n O X X O

An - C - C - R3 - C Corey II
lo lo O R Al O
If l l 11 An - C - C X' C - C - An III

2 lo Al IV
I SUE X

wherein n is l or 2, An in formula I, if n is l, and in formula II
and III represents aureole of 6 to 14 carbon atoms, phenol which is substituted by Of, Bra ON, OH, elk, -Oak, -Salk, Salk, -SO2phenyl, -Cowlick, -SNOW, -Swanlike, -Swanlike, -N(alk)2, phonics or NHCOalk, or represents thinly, pyridyl or fury, where-in elk represents a lower alkyd radical of l to 4 carbon atoms, and, An in formula I, if n is 2 represents Arlene of 6 to I
carbon atoms or a phenylene-T-phenylene group, X represents one of the groups -NO R , -OR , -oozier) (R8~2, hydroxymethoxy, (Cl-C4alkoxy)methoxy, (C2-C8acyloxy)methoxy or together with ( 1 C8alkyl)-O(CH2)1 I -OCH(C C 1) . -:

~1~3~
a --(Shelley -OCH(Cl-C8alkyl)- or -OCH(C6-C14aryl)-, X' represents one of the groups -NO I, -N (phenol)-, -N N- or -N(R10)-R
NOR )-, represents a direct bond or -SHEA-, represents -O-, -S-, -SO-, -SHEA- or -C(CH3)2-, T represents -O-, -S-, -SO-, -SHEA- or -CH=CH-, R in formula I, if n is 1 and X is -or, repro-sets Cluck alkyd which can be substituted by C2-C8 acyloxy, -COO-(Cluck) alkyd or -ON, or represents C5-C6~ycloalkyl or C7-Cgphenyl-alkyd, and, in all other cases, represents alkyd of 1 to 8 carbon atoms which can be substituted by OH, ~l-C4alkoxy, C2-C8acyloxy, -COO(Cl-C4)alkyl or -ON, or represents cycloalkyl of 5 to 6 carbon atoms or phenylalkyl or 7 to 9 carbon atoms, R2 has one of the r meanings assigned to Al or represents ally, methylallyl 2-carbamoylethyl, 2-(N-Cl-C~alkylcarbamoyl)ethy]. 2-(N,N-di-Cl-C4-alkylcarbamoyl)ethyl,~2-(2-pyridyl)ethyl, 2-(2-oxo-1-pyrrolidinyl)-ethyl or 2-(di-O-Cl-C4-alkylphosphono)ethyl, or Al and R2 together represent alkaline of 4 to 6 carbon atoms or oxaalkylene or azaalkylene of 3 to 4 carbon atoms, or R and R in formula I are both hydroxymethyl, R3 is a direct bond, alkaline of 1 to 6 carbon atoms, oxaalkylene of 2 to 6 carbon atoms, thialkylene of 2 to 6 carbon atoms, ,S-oxothiaalkylene of 2 to 6 carbon atoms, S,S-dioxathiaalkylene of 2 to 6 carbon atoms, phenylene, diphenylene or a -phenylene-T-phenylene group, or both substitu-ens R2 together with R3 and both carbon atoms to which these sub-stituents are attached form a cyclopentane or cyclohexane ring, I
represents alkyd of 1 to 12 carbon atoms, alkyd of 2 to 4 carbon atoms which is substituted by -OH or -Oak, or represents ally/
cyclohexyl, phenylalkyl of 7 to 9 carbon atoms, phenol or phenol ' 123~

which is substitutec1 by C1, elk, Owl, -Oak or -Cowlick, R5 repro-sets alkyd of 1 to 12 carbon atoms, alkyd of 2 to 4 carbon atoms which is substituted by -OH or -Oak, or represents ally, cycle-Huxley or phenylalkyl or 7 to 9 carbon atoms, or together with R4 represents alkaline of 4 to 5 carbon atoms which can be inter-rutted by -O- or -Salk-, or, in the case of compounds of the formula I, together with R2 represents alkaline or phenylalkylene of 1 to 9 carbon atoms or ox~alkylene or azaalkylene of 2 to 3 carbon atoms, R6 represents hydrogen, alkyd of 1 to 12 carbon atoms, alkyd of 2 to 4 carbon atoms which is substituted by -OH or -Oak, or represents ally, cyclohexyl, bouncily, phenol or phenol which is substituted by Of or elk, R7 and R8 are the same or dip-fervent and represent alkyd of 1 to carbon atoms or phenol, R10 represents alkyd of 1 to 8 carbon atoms, cyclohe~yl or bouncily, and Roll represents alkaline of 2 to 8 carbon atoms, xylylene, phenylene or a -phenylene-T-phenylene group; with the proviso that if, in formula I n is 1, and An is phenol, or phenol substituted by Of, Bra alkyd, alkoxy or dialkylamino and X is OH or alkoxy, then R1 and R2 are not unsubstituted alkyd, as sensitizers for the ., photopolymerisation of unsaturated compounds and for the photo-chemical cross linking of polyolefins.
These compounds are accordingly aromatic-aliphatic kittens, the Caribbean atom of which is tertiary and which are sub-stituted by a hydroxyl or amino group or the etherification or silylation products thereof. The aliphatic residue can also be cycloaliphatic or araliphatic or linked to the aromatic residue with ring closure, which corresponds to the benzocyclic kittens of the formula It.

~.,.~.

~3~4~
- pa , Of the substituents listed above, Al, R2, no and R10 can be alkyd of 1 to 8 carbon atoms, for example methyl, ethyl, propel, bottle, Huxley or octal. R4, R5 and R6 as alkyd can be unbranched or branched alkyd of 1 to 12 carbon atoms, for example methyl, ethyl, isopropyl left -bottle, isoamyl, n-hexyl, 2-ethylhexyl, n-decyl or n-dodecyl. Ask represents a lower alkyd radical of 1 to 4 carbon atoms, for example methyl, ethyl, isopropyl, n-butyl or left -bottle.
Al, R2 and R6 as hydroxyalkyl, alkoxyalkyl or acyloxy-alkyd can be for example hydroxymethyl, l-hydroxyethyl, 2-hydroxy-ethyl, 2-isopropoxyethyl, l-hydroxyisobutyl, l-acetyloxybutyl, l-acryloyloxyhexyl, l-hydroxyoctyl, 3-benzoyloxypropyl, methoxy-methyl or isobutyloxymethyl. The azalea radical can be the radical of an aliphatic or aromatic ,, .
., lZ34,'~

carboxylic acid. Preferably they are l-hydroxyalkyl radicals and their ethers or esters R and R5 as hydroxyalkyl or alkoxyalkyl can be fox example 2-hydroxyethyl, 2-butoxyethyl, 2-methoxypropyl, 3-hydroxypropyl or 2-ethoxybutyl. Prefer-ably they are 2-hydroxyalXyl radicals and the ethers there-of.

Al and R2 as alkyd which is substituted by -NO US
can be for example dibutylaminomethyl, 2-piperidinoethyl or 2-dimethylaminopropyl.

R , R , R , R or R as CN-substituted alkyd can be for example 2-cyanoethyl, 2-cyanopropyl or 4-cyanobutyl, whilst Al, R and R can also be for example cyanomethyl, 2-cyanohexyl or 4-cyanooctyl. The 2-cyanoethyl radical is preferred.

Al, R and R as alkyd substituted by -Cowlick can be for example -CH2COOC2H5, -C~2CH2COOCH3, -(SHEA-COUCH or -CH2-CH(C2H5~-COOC~H9. R as alkyd substituted by -CONHalk or -CONH(alk)2 can be for example -CH2CONHCH3, -CH2CH2CON(CH3)2 ox -CH2CH(CH3)-CONHC4Hg.

Al, R2, R4, R5 and R as alkenyl can be for example ally, methallyl or buttonhole.

R and R as cycloalkyl can be cyclopentyl or cyclohexyl. Al, R , I and R5 as phenylalkyl. can be for example bouncily, phenylethyl or dimethylbenzyl.

An as aureole or substituted phenol can be for example phenol, naphthyl, phenanthryl, anthracyl, diphen~l-ye, chlorophenyl, bromophenyl, dichlorophenyl, mustily, isopropylphenyl, phenoxyphenyl t cyanophenyl, p-nonylphenyl hydroxyphenyl, toll, left -butylphenyl, xylyl, isopropyl-~342~

chlorophenyl, methoxyphenyl, ethoxyphenyl, phenoxyphenyl,chlorotolyl, bromoxylyl, methylthiophenyl, phenylthiophenyl, butylsulfophenyl, phenylsulfophenyl, ethoxycarbonylphenyl, left -butoxycarbonylphenyl, methylaminosulfophenyl, dipropyl-aminosulfophenyl, dimethylaminophenyl, benzoylaminophenyl or acetylaminophenyl.

Al and R together can represent alkaline or ox-alkaline or azaalkylene. In this case, Al and R together with the carbon atom to which they are attached form a cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, tetrahydrofurane, tetrahydropyrane, purl-dine or piperidlne ring.

R and R together can represent alkaline or phenylalkylene of 1 to 9 carbon atoms or oxaalkylene or azaalkylene. on this case, R and R5 together with the carbon atom to which R is attached and the nitrogen atom to which R is attached form a 3- to 6-membered ring, for example an aziridine, azetidine, pyrrolidine, imidazolidine, piperidine, piperazine or morpholine ring.

R4 and R together can represent alkaline of 4 to 5 carbon atoms which can be interrupted by -O- or -NR14-~ In this case, R and R5 together with the nitrogen atom to which they are attached Norm a pyrrolidine, piper-dine, morpholine, 4-alkylpiperazine, 4-cyanoethylpipe~azine or 4-alkoxycarbonylethylpiperazine ring.

I
Jo ;~34;2~

g R can be alkaline of 1 to 16 carbon atoms and Roll and R can be alkaline of 2 to 8 carbon atoms. Examples of such alkaline groups, within the stated number of carbon atoms, are: ethylene, ethylene, 1,3-propylene, 1,4-battalion, 2,2-dimethyl-1,3-propylene, 1,6-hexylene, methyl

3-ethyl-1,4-butylene or 1,8-octylene. R can also be ox-alkaline, thiaalkylene and moo- or dioxothiaalkylene of 2 to 6 carbon atoms for example 2-oxa-1,3-propylene, 3-oxa-2,4-pentylene, 3-oxa-2,4-pentylene, 3-oxa-1,5-pentyl-ennui -CH2SCH2-~ -CH2cH2socH2cH2- or -(CH2)3-so2-tcH2)3-.

An can be Arlene of 6 to 12 carbon atoms, for example phenylene, naphthylene or diphenylene.

If Y is a direct bond, the compounds of the formula IV constitute derivatives of indanone, cumarone or thiocumaranone. If Y is SHEA, they are derivatives of twitter-lone, chromanone or thiochromanone.

~4Z9~
g Preferably, the invention is concerned with the use of compounds wherein n is 1 or 2, An in formula I, if n is 1, and in formula II and III represents C6-C14-aryl which is unsubstituted or substituted by one or more members selected from the group con-sitting of Of, Bra elk, -Oak, ~Ophenyl, -Cowlick, -N(Alk)2 or -NHCOalk and elk represents a lower alkyd radical of 1 to 4 carbon atoms, and, if n is 2, represents C6-C12arylene or a -phenylene-T-phenylene group, X represents one of the groups -NO R or -or, X' represents one of the groups -No JO- or -N(R10)-Rll-N(R10) Y
represents a direct bond or -SHEA- z represents -O-, -SHEA- or -C(CH3)2-, T represents -O- or SHEA-, Al in formula I, if n is 1 and X is -or, represents Cluck alkyd which is unsubs-tituted or substituted by -Cowlick or ON, or represents C7-Cgphenylalkyl, and in all other cases represents Cl-C8alkyl which is unsubstituted or substituted by OH, Oak, -Cowlick or -ON, or is C7-Cgphenylalkyl, R2 has one of the meanings assigned to Al or is ally or a -CHESHIRE group, or together with R represents C4-C6alkylene or C3-C4oxa- or azaalkylene, R3 represents a direct bond or Cluck-alkaline or together with both substituents R2 and both carbon atoms to which these s~stituents are attached forms a cycle-pontoon or cyclohexane ring, R4 represents Cl-C12alkyl, C2-C4alkyl which is substituted by OH or Oak or represents ally, R5 repro-sets Cl-C12alkyl, C2-C4alkyl which is substituted by OH or Oak or represents ally or together with R4 represents C4-C5alkylene which can be interrupted by -O- or -Salk-, R6 represents hydrogen, Cl-C12alkyl, C2-C6alkyl which is substituted by OH or Oak, or is ally, bouncily, phenol, or together with Al represents C3-C4-I.. ..

~Z3~4~

alkaline or -CH2-O-CH2-, R represents Cl-C8alkyl, R represents C2-C8alkylene and Rl3 represents -COWAN, -CONHalk, -CON (Alec, up (Oalk)2 or 2-pyridyl, provided that, if in formula I n is l and An is phenol or phenol substituted by Of, Bra alkyd, alkoxy or dialkylamino and X is OH or alkoxy, Al and R2 is not unsubstituted alkyd.
Among these compounds, preferred compounds are those of the formula I, especially those compounds of the formula I in which n is l and X is OH and Al and R2 together represent C2-C5-lo alkaline.
Most preferably, the invention is concerned with the use of compounds of the formulae I, II or III, wherein n is l or 2, An in formula I, if n is l, and in formula II and III represents C6-Cl4aryl which is unsubstituted or substituted by Of, By or Oak and elk represents a lower alkyd radical of l to 4 carbon atoms, and An in formula I, if n is 2 represents C6-Cl2arylene or a -phenylene-T-phenylene group, X represents one of the groups -NR4R5 or -or, X' represents the group -N N-, T represents -O-or -SHEA-, R represents Cl-C8alkyl, R represents -Cl-C8alkyl or ally, R3 represents a direct bond or Cl-C6alkylene, R4 represents Cl-Cl2alkyl, R5 represents Cl-Cl2alkyl or together with R4 repro-sets C4-C5alkylene which can be interrupted by -O- or -Salk- and R6 represents hydrogen, Cl-Cl2alkyl, C2-C4alkyl which is subset-tuned by OH or Oak or represents ally, bouncily, phenol, provided that, if in formula I n is l and An is phenol or phenol subset-tuned by Of, Bra alkyd, or alkoxy or dialkylamino and X is OH or alkoxy, Al and R2 is not unsubstituted alkyd.

~34~Z

Among these compounds, those compounds of the formula I
or II are preferred in which X represents alcoholics, C1-C6hydroxy-alkoxy or alkoxyalkoxy, benzyloxy or phenyloxy, and also the come pounds of the formulae I, II or III in which An represents p-phenoxyphenyl or a tetrahydronaphthalene radical.
Examples of eligible compounds of the formula I, wherein n is 1, are: 2-hydroxy-2-methyl-(p-phenoxypropiophenone), 2-hydroxy-2-methyl-(p-acetylaminopropiophenone), 2-hydroxy-2-methyl-(p-methylthiopropiophenone), 2-hydroxy-?-methyl-(p-carbo-ethoxy-propiophenone), 2-phenoxy-2-methyl-~Z3~24~

propiophenone, 2-allyloxy-2-methyl-propiophenone, 2-benzyloxy-2-methylpropiophenone, 2-methoxyethoxy-2-methyl-propiophenone, 2-hydroxyethoxy-2-methylpropiophenone, 2-(o-hydroxyphenoxy)-2-methylpropiophenone, 2-(2-carboethoxyphenoxy)-2-methylpropio-phenone,2-methyl-2~piperidino-2-phenyl-3-hydroxypropiophennone, 2-methyl-2-morpholino-3-phenyl~3-hydroxypropiophennone, 2-methyl-2-dimethylamino-3-phenyl-3-hydroxy-propiophenone, ~-hydroxy-~-~-bis-(cyanoethyl)-acetophenone, y-hydroxy-~-benzoylpimelate deathly-ether,2-hydroxy~2-methyl-3-phenyl-3-dimethylaminopropiopphenone, 2-di-(2-hydroxyethyl)-amino-2-methyl-3-phenylpropiiophenone, 2-methyl-2,3-dipiperidino-3-phenylpropiophenone, 2-dimethylamino-2-methylpropiophenone, 2-diethylamino-2-methylpropiophenone, 2-dibutylamino-2-methylpropiophenone, 2-di-hydroxyethylamino-2 methylpropiophenone, 2-piperidino-2-methylpropiophenone, 2-(2-methylpiperidino)-2-methylpropiophenone, 2-morpholino-2-methyl-propiophenone, 2-piperazino-2-methylpropiophenone, methyl-piperazino) 2-methylpropiophenone, 2-pyrrolidino-2-methylpropio-phenone, 2-methylphenylamino-2-methylpropiophenone, l-benzoyl-cyclohexanol, l-benzoyl-cyclopentanol, l-benzoyl-cyclopropanol, 3-p-methoxybenzoyl-3-dimethylaminoheptane, 6-(2-morpholino-isobutyryl)-tetraline, 6-(2-piperidino-isobutyryl)-tetraline, 6-(2-piperazino-isobutyryl)tetraline, 2-~2-methoxybenzoyl)-2-diallyl-amino propane, ~23~2~1~
- 1.3 -2-(2-thenoyl)-2-piperidinopropane, 2-p-phenylbenzoyl-2-di-(2-hydroxyethyl)-aminopropane, l-methyl-2-o-chlorobenzoyl-piperidin, l-benzyl-2-benzoyl-3-phenylaziridine, 1-cyclohexyl-2-benzoyl-3-phenylaziridine, 2-o-toluyl-2-(trimethylsiloxy)-propane, 5-methyl-5-benzoyl-1,3-dioxolane, 2,5-dimethyl-5-benzoyl-1,3-dioxolane, 2-phenyl-5-methyl-5-benzoyl-1,3-dioxolane, 5-methyl-5-~p-isopropyl-benzoyl)-1,3-dioxolane, 2,3-epoxy-2-methyl-3-phenylpropiophenone, 2-hydroxy-2-methyl-3-dimethylaminopropiophenone, 2-hydroxy-2-methyl-4-N,N-diethylcarbamoylbutyrophenone, 2-morpholino-2-methyl-ANN diethylcarbamoylbutyrophenone, 2-hydroxy-2-methyl-4-(2-pyridyl)-butyrophenone, 2-hydroxy-2-methyl-4-diethylphosphono-butyrophenone, 2-hydroxy-2-benzylpropiophenone, 2-hydroxy-2-(p-methylbenzyl)-propiophenone, 2-hydroxy-2-cyclohexylpropiophenone, 2--hydroxy-2-cyclopentylpropiophenone, 2-(2-hydroxyethoxy)-2-methyl-propiophenone, 2-hydroxy-2-allylpropiophenone, 2-hydroxy-2-methyl-4-(2-oxo-1-pyrrolidinyl)-butyrophenone, 2-methylthio-2-methyl prop-phenone.

Examples of compounds of the formula I, wherein n is 2, are: 4,4'-bis-(a-hydroxy-isobutyryl)-diphenyl oxide,

4,4'-bis-(a-hydroxy-isobutyryl)-diphenyl, 4,4'-bis-(a-hydroxy--isobutyryl)-diphenyl sulfide,~,4'-bis- (a-hydroxy-iso.butyryl)-diphenyl methane, 4,4'-bis-la-piperidino-isobutyryl)-di-phenol oxide, 4,4'-bis-~a-(isopropylamino)-isobutyryl]-di-phenol, 4,4'-bis-(a-ben~oyloxy-isobutyryl)-diphenyl oxide, .

~23~

Examples of compounds of the formula II are:
1,4-diphenyl-2,3-dimethyl-2,3-dihydroxy-butanedionNoah, 2,4-dibenzoyl-2,4-dihydroxypentane, 2,9-dibenzoyl-2,9-di-methyl-3 r 8-dioxadecane, 2,7-dibenzoyl-2,7-dimethyl-3,6-dioxa-octane, 1,6-diphenyl-2,5-dimethyl-2,5-dihydroxy hexanedione-1,6, 1,4 diphenyl-2,3-dimethyl-2,3-bis-(dimethylamino)-butanedione-1,4~1~4-diphenyl-2/3-dimethyl-2/3-dipiiperidyl-butanedione-1,4,l,2-bi5-hydroxy-1,2-bis-benzoyl-cyyclohexane, 1,2-bis-dimethylamino-1,2-bis-benzoyl-cyclohexane,, Boyce-morpholino-1,2-bis-benzoyl-cyclohexane, bis-(3-hydroxy-3-benzoylbutyl)-sulfone.

Examples of compounds of the formula IV are:
l-oxo-2-dimethylamino-2-methyl-1,2,3,4-tetrahydronnaphthalene, l-oxo-2-hydroxy-2-methyl-i,2,3,4-tetrahydronaphthaclone, l-oxo-2-hydroxy-2-methylindane.

Some of the compounds of the formulae I, II, III
and IV are known compounds, and others are novel.

Known compounds are those of the formula I, where-in n is 1, An represents phenol, phenol which is substituted by methyl or methoxy, or is fury, Al and R2 are methyl or R and R together represent alkaline and X is hydroxyl, methoxy or nitrophenoxy.

,, .
, us ,~, ~L23~

Known compounds are those of the formula I, where-in n is 1, An represents phenol, chlorophenyl or diphenylyl, Al and R are methyl or morpholinomethyl, or Al and R to-getter are alkaline and X is a -~R5R6 group, in which each of R and R6 is alkyd or bouncily or R5 and R6 together no-presents alkaline or oxaalkylene.

A known compound is also a compound of the formula II, wherein An represents phényl, Al represents methyl, X
represents hydroxy and R3 is a direct bond.

The known compounds have up to now not been proposed as photosensitizes.

YO-YO. .

1~3~

The novel compounds can be prepared by methods analogous to those for obtaining the known compounds, where-by different methods are possible.

Accordingly, the compounds of the formula I can be prepared from aromatic-aliphatic kittens by the follow-in reaction steps:

An CO-CHR1R2] By n An C - C HO An C - C - ]
OUCH R

As HO it is possible to use amine [CAL. Stevens, Oh. Hung Change J. Org. Chum. 27 (1962), 4392] or water or carboxylic acids CLUE. Stevens, E. Parkas, J. Am. Chum. Sock 74 (1952), 618 and CAL. Stevens, SO Dexter, J. Am. Chum.
Sock 75 (1953), 5976].

In many cases the direct reaction of the Abram-kittens to give compounds of the formula I
O Al An CO CBrRlR2 ] Ho Jo An C C - X I

I Lo is also possible, for example with amine, alkali hydroxides or alkali phenoxides. Instead of bromide compounds it is also possible to use the corresponding chlorine compounds.

The resulting hydroxyketones of the formula I
(ZOO) can be etherified or O-silylated by the conventional methods.

Compounds of the formula III are obtained by using a difunctional compound of the formula HUH instead of the monofunctional compound HO in the above reactions.

The compounds of the formula II can be prepared analogously to those of the formula I by using Dakotans of the general formula An - CO - OH - R3 - OH CO - An The compounds of the formula IV are obtained in analogous manner starting from cyclic kittens of the formula Jo o I

Compounds of the formula I, wherein Al is a sub-stituted alkyd group, can be obtained from the compounds of the formula Ar~CO-CH(R On by reaction with aldehydes (R = hydroxyalkyl) or with a vinyl compound which is cap-able of addition, for example with acrylates or acrylonit-rile. In the same way, a -CH2CH2-Rl group can be introduced as R2, starting from a compound ArfCO-C~(R1)-X] . If both Al and R2 are substituted alkyd, then both substituents:can .. , . , . . ... ... , . .. . . . ... . , .. . . .. . ..... , .. ,, .. .. . ... , .. --. . . . . ... .
. .

Z34~

be introduced jointly by reaction of a compound Ar~CO-CH2-On with at least 2 moles of an alluded or a vinyl compound.
The corresponding alkoxyalkyl and acyloxyalkyl groups can be obtained from the hydroxyalkyl groups Al and/or R2 by ether-ligation or esterification. Compounds of the formulae II, III and IV containing substituted alkyd groups as Al or R
can be obtained in analogous manner.

Compounds in which X together with Al is a -OUCH
(R9) group are a-oxydoketones and can be obtained by epo~i-ration of the corresponding a-vinyl kittens. Reaction of the oxydoketones with secondary amine affords compounds in which either X is OH and Al is an aminoalkyl group, or in which X is NR4R and Al is a hydroxyalkyl group.

Addition of bromide to the a-vinyl kittens yields a,~-dibromoketones of the formula ArfCO-CBr(R )-CBralk]n.

Reaction of the dibromoketones with one mole of a primary amine yields the corresponding a-~aziridinoketones Shea. o C, A Nat - 6b~. - ~#~ 65 (1943), 312], and reaction with 2 moles of a secondary amine yields compounds of the formula I, wherein X is -NO R and R is an aminoalkyl radical [J. Am.
Chum. Sock 74 (1952), 1886].

Amlnoalkyl groups Al and/or R can also be intro-duped by the Mannish reaction, wherein kittens a the for-mute Ar~CO-CHRl-X]n or Ar~CO-CH2-X]n are reacted with 1 or 2 moles of formaldehyde and a secondary amiss.

Whereas all these methods of synthesis start from an aromatic-aliphatic kitten into which a subctituent X is introduced in a different manner, it is also possible in specific cases to introduce the substituent X during the kitten synthesis by the Friedel-Crafts reaction in accord . .

I

dance with the reaction scheme:
Al Al I C - Cowl + Ash An - CO- C - X

This presupposes that the substituent X is not attacked under the conditions of the Friedel-Crafts reaction.
In this way it it possible for example by using heterocyclic carboxylic acid chlorides to prepare compounds of the formula I, in which X and Al together with the carbon atom to which they are attached form a heteroring.

According to the invention, the compounds of the formulae I, II, III and IV can be used as sensitizers for the photopolymerisation of unsaturated compounds or systems which contain such compounds.

Such compounds are for example unsaturated moo-mews, such as esters of acrylic or methacrylic cold, for example methylacrylate, ethylacxylate, n- or tert-butyl~
acrylate, isooctylacrylate or hydroxyethylacrylate, methyl-or ethylmethacrylate, ethylene diacrylate, neopentyl die-cruelty, trimethylolpropane trisacrylate, pentaerythritol tetraacrylate or pentaerythritol trisacrylate; acrylo-nitrite, methacrylonitrile, acrylamide, methacrylamide, N-substituted acrylamides and methacrylamides; vinyl esters, such as vinyl acetate, vinyl preappoint, vinyl acrylate or vinyl succinate; other vinyl compounds, such as vinyl ethers styrenes alkyd styrenes, halo styrenes divinely Bunsen, vinyl naphthalene, N-vinylpyrrolidone, vinyl chloride or vinylidene chloride; ally compounds, such as Delilah phthalate, Delilah Malta, triallyl isocyanurate, --triallyl phosphate or ethylene glycol Delilah ether and: the -Jo mixtures of such unsaturated monomers.

Photopolymerisable compounds are in addition us-saturated oligomers or polymers and the mixtures thereof with unsaturated monomers. These include thermoplastic resins which contain unsaturated groups, such as fumaric acid ester groups, ally groups or acrylate or methacrylate groups. These unsaturated groups are usually bound through functional groups to the main chain of these linear polyp mews. mixtures of oligomers with simply and polyunsaturated monomers are very important. Examples of such oligomers are unsaturated polyesters, unsaturated acrylic resins and is-Senate or epoxide modified acrylate oligomers as well as polyether acrylate oligomers. Examples of polyunsaturated compounds are in particular the acrylates of dills and polyp owls, for example hexamethylene diacrylate or pentaerythri-lot tetracrylate. Acrylates are also preferred as simply unsaturated monomers, for example bottle acrylate, phenol acrylate, bouncily acrylate, 2-ethylhexyl acrylate or 2-hydroxypropyl acrylate. By choosing from the different representatives of the three components, the opportunity is afforded to vary the consistency of the unpolymerized mixture as well as the plasticity of the polymerized resin.

In addition to these three-component mixtures, two-component mixtures especially are ox great importance among the polyester resins. These usually consist of an us-saturated polyester and-a vinyl compound. The unsaturated polyesters are oligomer esterification products of at least one unsaturated dicarboxylic acid, for example malefic,-fumaric or citraconic acid and usually of at least one saturated dicarboxylic acid, for example phthalic acid, succinic acid, sebacic acid or isophthalic acid, with Jo glycols, for example ethylene glycol, propanediol-1,2, ; -dip or triethylene glycol or tetramethylene glycol/ whilst :~Z3~

, Jo monocarboxylic acids and monoalcohols are generally also used concurrently for the modification. These unsaturated polyesters are normally dissolved in a vinyl or ally come pound, styrenes being preferably used for this purpose.

Photopolymerisable systems which are used for the different purposes usually contain in addition to the photopolymerisable compounds and the photosensitizes, a number of other ingredients. It is therefore often customary to add heat inhibitors in order to prevent a premature polyp merisation, especially during the preparation of the systems by mixing the components. ~ydroquinone, hydroquinone derive-lives, p-methoxyphenyl, ~-naphthylamine or ~-naphthols are used for example for this purpose. Furthermore, small amounts of US absorbers can be added, for example those of the benztriazole or benzophenone type.

To increase the storage life in the dark, it is possible to add copper compounds, such as copper naphthenate, copper Stewart or copper octet, phosphorus compounds, such as triphenylphosphine, tributylphosphine, triethyl phosphate, triphenyl phosphate or tribenzyl phosphate, qua ternary Anaheim compounds, such as tetramethylammonium chloride or, trimethylbenzylammonium chloride, or hydroxyl-amine derivatives, for example N-diethylhydroxylamine. In addition, the photopolymerisable systems can contain chain transfer agents, for example N-methyl-diethanolamine, in-e~hanolamine or cyclohexene.

In order to exclude the inhibiting action of - -atmospheric oxygen, paraffin or similar alike substances are frequently added to photo hardening systems. On account of their poor volubility in the polymer, these substances float at the beginning of the polymerization and form a;
transparent surface layer which prevents the entry of air Jo 4~Z

I "' .
.,, The atmospheric oxygen can also be deactivated by introduce in autoxidisable groups, for example ally groups, into the resin to be hardened.

Depending on the end-use, photopolymerisable systems also contain fillers, such as silicic acid, talc or gypsum, pigments, dyes, fires, thixotropic agents or level-lying agents.

Combinations with known photosensitizes, such as Bunsen ethers, dialkoxy acetophenones or bouncily petals, can also be used Combinations of the photosensitizes of the invention with amine and/or aromatic kittens can be used especially for the photopolymerisation of thin layers and printing inks. Examples of amine are triethylamine, N-methyldiethanolamine, N-dimethylethanolamine or pi methylaminobenzoate. Examples of kittens are benzophenone, substituted benzophenone derivatives, Michler's kitten, anthraquinone and anthraquinone derivatives, as well as thioxanthone and the derivatives thereof.

Photo hardening is of great importance for print--lung inks, since the drying time of the binder is a decisive factor in the production speed of printing products and should be in the order of fractions of seconds. The sense-titers of the invention are also very suitable for photo-hardening systems for the manufacture of printing plates.
Mixtures of soluble linear polyamides with photopolymeris-able monomers, for example acrylamides, and a photosensi-titer, are usually employed for this purpose. Films ox plates prepared from these systems are exposed via the negative (or positive) of the original and the unhardened portions are subsequently eluded with a solvent. ---. .

:, -123~'~4'~

"
further field of use of US hardening is metal coating, for example in the varnish coating of metal sheeting for tubes, cans or bottle caps, as well as the W hardening of plastic coatings, for example of floor or wall coverings based on PVC.

Exemplary of the W hardening of paper coatings is the colorless varnish coating of labels, gramophone record sleeves or book jackets.

cording to the invention, the compounds of the formulae I, II, III and IV can also be used as sensitizers for the photo chemical crosslinkin~ of polyolefins, for example polypropylene, polybutene, polyisobutylene and also copolymers, for example ethylene/propylene copolymers, but preferably polyethylene of low, medium or high density.

The photosensitizes are advantageously used for the above fields of use in amounts of 0.1 to 20~ by weight, preferably about 0.5 to 5% by weight, based on the photo-polymerisable or crosslinkable system. The term "system"
is to be understood as meaning the mixture of the photo-polymerisable or crosslinkable compound, the photosensitizes and the other fillers and additives, as it is used in the-respective application.

The addition of the photosensitizes to the photo-polymerisable systems is accomplished in general by simple stirring, since most of these systems are fluid or readily soluble. Usually the sensitizers of the invention dissolve in the system, thereby ensuring their uniform distribution and the transparency of the polymers.

The polymerization is carried out by the known methods of polymerization by irradiation with fight which .. . .. , . . ..

I
I
Jo is rich in shortwave radiation. Suitable light sources are for example mercury medium pressure, high pressure and low pressure lamps, as well as superactinic fluorescent tubes, the emission peaks of which are in the range between 250 and 400 no.

The following Examples describe the manufacture and use of compounds of the formula I in more detail. Parts and percentages are by weight.

. . . . : .. : : . .. . -~23'~

Manufacture and properties of the compounds used in Examples 1 to 6 _ The compounds listed in Table 1 were obtained by one or more of the methods A to L.

Method A Chlorination of aromatic-aliphatic kittens Ar~CO-CR R H] n + n C].2 ~Ar~CO-CR R Of] n + n Hal The kitten is dissolved in an inert solvent, preferably in tetrachloromethane, and the calculated amount of chlorine is introduced into the solution at 40-80C. Nitrogen is then introduced to remove dissolved Hal. Finally, the sol-vent is distilled off. Purification of the chloroketone is usually not necessary and the product can subsequently be reacted by method D, F or H.

Method B Bromination of aromatic-aliphatic kittens Ar~C0-CRlR2H]n n Bra Ar~CO-CRlR or] n + n Her The calculated amount of bromide is added drops at room temperature to a solution of the kitten, f or example in CC14. Working up and further processing are effected as in Method A.

Method C Chlorination with sulfuryl chloride Ar~C0-CRlR2H] 2 C12 Ar~C0-CRlR Of]

+ n S02 + n Hal The sulfuryl chloride is added drops at 40C to a soul-lion of the kitten in CC14. Working up and further process-in as in Method A.

~234~

, .. . ..
Method D Preparation of the epoxide intermediate Ar~CO-CRlR2Hal]n n NaOCH3--~Ar~C - OR R on + n Naval OUCH
Hal = Of or By The haloketone is dissolved in methanol and a solution of the stoichiometric amount of sodium methoxide in methanol is added drops at reflex temperature. The methanol is then distilled off and the residue is poured into ice water and extracted with ether. The ethereal solution is washed with water, dried over Nazi, dried and concentrated. The residue is purified by recrystallization or vacuum distill lotion. The epoxide can subsequently be reacted by Method E
or G.

Method E Hydrolysis of the epoxide An I Cruller ] + n H20 H Ar~CO-CRlR20H]n on SHEA
OUCH
The epoxide is covered with 2 to 5 times its weight of water and the mixture is reflexed for 1 to 2 hours with the add-lion of a catalytic amount of mineral acid. After cooling, the reaction mixture is extracted with ether. The ethereal solution it washed with water, dried over Nazi, and con-cent rated. The residue (crude hydroxyketone) is purified by distillation or crystallization or column chromatography.
The properties of the pyre a-hydroxyketones are indicated in Table 1.

Method F a-Hydroxyketones from a-haloketones Ar~CO-CRlR Helen + n Noah _ Ar~CO-CRlR20H]n + n Naval 1~3~ Z

Z

The a-haloketone is reflexed in dilute or concentrated sodium hydroxide solution (20% excess of Noah). When the hydrolysis is complete (check by chromatography), the crude hydroxyketone is isolated and purified as described in Method E. The pure hydroxyketones are listed in Table 1.

Method G a-Aminoketones from the exudes -Arc - Cruller] R4R NH _ Ar~CO-CRlR2-NR4RS] on SHEA
OUCH

The epoxide is treated with the stoichiometric amount of the amine, either without a solvent or with the addition of a small amount of Tulane or zillion, and reacted or about 10 to 20 hours at 100-200C. When using low boiling amine, for example dimethylamine or diethylamine, the reaction is carried out in an autoclave. The reaction mixture is diluted with Bunsen and extracted with dilute hydrochloric acid.
The aqueous acid solution is made alkaline with Noah and extracted with ether. The ethereal solution is washed with water, dried over Nazi and concentrated. The crude product is purified by distillation or crystallization. The a-amine-kittens are listed in Table 1.

Method H a-Aminoketones from the a-haloketones Ar~CO-CRlR Hal] n on R4R NH Ark Cruller NR4R5]
n R R Noel The ~-haloketone, undiluted or diluted with Tulane, i-s mixed with 2 molar equivalents of the amine and the mixture is heated for 10 to 20 hours to 100-200C. when using low boiling amine, for example dimethylamine or diethylamine, the reaction is carried out in an autoclave. Isolation and I

purification are effected as in Method G.

Method I Introduction of A carbalkoxyethyl group CH2CH2CAl Ar~CO-CHRl On + n SHEA = CH-COOAlk--~Ar~CO-CRl-X ] n The kitten is dissolved in dim ethyl sulfoxide. To the soul-lion are then added 1.1 molar equivalents of Noah in the form of ON sodium hydroxide solution and, with cooling, 1.1 molar equivalents of acrylate are added drops at room temperature. The reaction mixture is diluted with ice-water and extracted with Tulane. The Tulane solution is washed neutral with water, dried over Nazi and concentra ted. The crude product is purified by column chromatography or crystallization.

Method K Etherification of hydroxyketones Ar~CO-CRlR -One n Rowley + n NaOH----~Ar~CO-CRlR2-OR6]n n Naval The a-hydroxyketone it dissolved in about 4 times its weight of dim ethyl sulfoxide and, while cooling to 10-20C and :
with stirring, 1 molar equivalent of the alkyd halide Rowley and 1 molar equivalent of concentrated sodium hydroxide solution are added drops simultaneously from two drip funnels. The reaction mixture is then stirred for 3 hours at room temperature. Precipitated sodium halide is then removed by filtration, the filtrate is washed with water, dried over Nazi and concentrated. The crude product -is purified by column chromatography, crystallization or vacuum distillation. Examples of eligible halogen compounds are methyl iodide, isopropyl bromide ally bromide, cycle- Jo Huxley bromide, bouncily chloride or ethyl chloroacetate. -I

`,`~ ..
Instead of using an alkyd halide, it is also possible to use a dialkyl sulfate or alkylaryl sulfonate as etherifying reagent.

Method L Cyclisation of X and Ar-CO-CHHal-R2 + SHEA Ar-CO-CR Hellish Nikko Ark- C~2 + Naval + SHEA

Paraformaldehyde is dissolved in 20 times its weight of methanol. To the solution is then added 1 molar equivalent of sodium methoxide (dissolved in a small amount of methanol).
While cooling to 0~5C, a concentrated solution of the a-haloketone is added drops. The reaction mixture is sub-sequently stirred for 1 hour at 5-10C and for 1 hour at room temperature. The reaction mixture is diluted with ether to 2 to 3 times its volume and poured into ice water. The aqueous mixture is extracted 3 times with ether and the ethereal extracts are washed with water, dried over Nazi and concentrated. The crude product is purified by distill lotion ox column chromatography.

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Example 1 A resin mixture consisting of 80 parts of Pled 6616 (acrylate resin, available from Room, Darmstadt), 20 parts of trimethylolpropane-trisacrylate and 2 parts of photo-sensitizer is applied with a film drawing device to glass plates in a thickness of 40,u. These films are exposed to air for about 20 seconds and then irradiated with a mercury medium pressure lamp (Hanovia device, Model 45080). In the course of the irradiation, the samples are passed underneath the lamp on a conveyer belt at a speed such that the effective exposure time is 0.16 second per run..

Table 2 indicates the number of runs (R) which were necessary in order to obtain non-tacky films. In addition, the hardness of the film was determined with a pendulum device by the method of Koenig. The final column indicates the storage stability of the resin-photosensitizer mixture in the dark at 60C.

*Trademark i I,...

~23~

Table 2 . _ _ _ . . _ Photosensitizes Runs Pendulum hardness accord Storage ding to Koenig after stability number of runs (R) in days . _ _ _ .
1 478(4R)94(6R) 98(8R) ~30 2 4101(4R)114(4R)116(8R) >30 11 373(5R) 13 395(3R)102(4R) 107(5R) >30 24 447(3R)72(4R) 88(5R) >30 . ._ _ a-hydroxypro- 368(3R)75(4R) 87(5R) piophenone (comparison) a-methylbenzoin 549(3R) 69(4R) 91(5R) (comparison) benzoin-tert~ 593(5Rl106(7R) 113(9R) ~30 butylether (comparison) funneled- 6112(6R)121(8R)130(lOR) ~30 methoxyaceto-phenone (comparison) p-methyl-a,a-di- 892(8R) lowlier) 109(12R) 5 morpholinoace-tophenone (comparison) a,a-dimorpholino- 17 84(17R) 98(19R) I
acetophenone (comparison) __ ._ _ .. _ .

-. I
I, ,, 1239~2g:~

Example 2 Resin mixtures consisting of 60 parts of viper DV-530 (urethane acrylate, available from Polyehrome~, 37 p its of hexanedioldiacrylate and 3 parts of photosensitizes were applied in a film thickness off to glass plates end irradiated as described in Example 1. The following results were obtained.

Table 3 _ .
_ No of runs Pendulum hardness rhotosensitizer necessary until wipe_ according to owing US
proof a function of R
.
1 . 3 129(3R) 157(7R) ! 3 144~3R) . 163 ( OR) diethoxyaceto- 10 156(10R) phenone (comparison) Bunsen left- 12 136~12R) bottle ether (comparison) funneled- 8 155 (OR) methoxyaceto_ phenone (comparison) . _ * Trademark I

. . _,~

2Z of photosensit$zer way disallowed in an saturated polyp I ester resin (Cystic PYRE 306, available from Madder, ~illwangen, Switzerland. These resin mixtures were applied on a firm ~hicknesx of 60~m to glass plates. The firms were irradiated us described in Example 1. The number of rut through the exposure device until the films were wipe-proof a well as the pendulum hardness as a function of R are reported in Table 4.

Table 4 . Jo. ox runs Pendulum hardness Photosensitizes necessary until wipe- according to Koenig as _ _ proof _ funcclo~ of R
1 13 21(13R) ire) 62(17R) 2 8 !0(8R~ awry) 89(12R) 28 (10R) I R) aye R) ~3~29 ' I

Example 4 Jo A resin mixture consisting of 90 parts of Laromer LO 8496 (acrylate resin available from BASS, lest Germany), lo parts of hexanediol diacrylate, 0.5 part of By 300 (leveling assistant available from ByK-Mallinckrodt, West Germany) and 3 parts of photosensitizes for hardening in the air or 0.5 part of photosensitizes for hardening under nitrogen is applied electromotively to cardboard boxes with a 15 helix. After brief exposure to air, hardening is effected with a W device (model PPG-QC-proces-son) with a W lamp of 80 watts/cm. The maximum trays-partition speed at which non-tacky films were obtained in air or under nitrogen is reported in Table 5 in m/min.

Table 5 ,____ Photosensitizes Transportation speed main air nitrogen ___ _ , ~00 7 30 1~0 8 30 Lowe lo 5 80 12 3,3 a ' 13 20 120 29 lo 90 __ !

~23~

Example S
*

resin mixture consisting of 70 parts of Ebercyl 593 (polyester acrylate available from CUB, Belgium), 30 parts of trimethylolpropane trisacrylate, 0.5 part of By 300 (leveling assistant available from ByK-Mallinckrodt, West Germany) and 3 parts of photosensitizes, is applied to glass plates in a layer of 30-40 I,. After brief expo-sure to air, hardening is effected with a W laboratory device (model PPG/QC-processer) with a W lamp of 80 watts/
cm. After the W hardening, the plates are stored for 1/2 hour under normal climatic conditions and then the hardness of the layers is determined using the pendulum device of Koenig. The hardness values as a function of the transportation speed under the lamp are reported in Table 6.
Table 6 .. _ Photosensitizes Pendulum hardness n 10 m/min. 25 McKee .. . _. . _ , 9 155 1~3 22 134 10~

*Trademark .,

Claims

THE EMBODIMENTS OF THE INVENTION AN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1, In a process for the photopolymerization of unsaturated com-pounds, the step of using as photosensitizer a compound of the formula:

I

I

III

IV

wherein n is 1 or 2, Ar in formula I, if n is 1, and in formula II and III represents aryl of 6 to 14 carbon atoms, phenyl which is substituted by Cl, Br, CN, OH, alk, -Oalk, -Salk, -So2alk, -SO2phenyl, -COOalk, -SO2NH2, -SO2-NHalk, -SO2N(alk)2, -N(alk)2, phenoxy or NHCOalk, or rep-resents thienyl 3 pyridyl or furyl, wherein alk represents a lower alkyl radical of 1 to 4 carbon atoms, and, Ar in formula I, if n is 2 represents arylene of 6 to 12 carbon atoms or a phenylene-T-phenylene group, X rep-resents one of the groups -NR4R5, -OR6,-O-Si(R7) (R8)2, hydroxymethoxy, (C1-C4alkoxy) -methoxy, (C2-C8acyloxy)methoxy or together with R1 represents -OCH(C1-C8alkyl)-O(CH2)1-2-, -OCH(C6-C14 aryl)-O-(CH2)1-2-, -OCH(C1-C8 alkvl)- or -OCH(C6-C14 aryl)-, X' represents one of the groups -NR10 ,-N
(phenyl)-, or -N(R10)-R11-N(R10)-, Y represents a direct bond or -CH2-, Z represents -O-, -S-, -SO2-, -CH2- or -C(CH3)2-, T represents -O-, -S-, -SO2-, -CH2- or -CH=CH-, R1 in formula I, if n is 1 and X is -OR6, represents C1-C8 alkyl which can be substituted by C2-C8 acyloxy, -COO-(C1-C4) alkyl or -CN, or represents C5-C6cycloalkyl or C7-C9phenyl-alkyl, and, in all other cases, represents alkyl of 1 to 8 carbon atoms which can be substituted by OH, C1-C4alkoxy, C2-C8acyloxy, -COO(C1-C4) alkyl or -CN, or represents cycloalkyl of 5 to 6 carbon atoms or phenyl-alkyl or 7 to 9 carbon atoms, R2 has one of the meanings assigned to R1 or represents allyl,methylallyl 2-carbamoylethyl, 2-(N-C1-C4alkylcarbamoyl) ethyl, 2-(N,N-di-C1-C4alkylcarbamoyl)-ethyl, 2-(2-pyridyl)ethyl, 2-(2-oxo-l-pyrrolidinyl)ethyl or 2-(di-O-C1-C4-alkylphosphono)ethyl, or R1 and R2 together represent alkylene of 4 to 6 carbon atoms or oxaalkylene or azaalkylene of 3 to 4 carbon atoms, or R1 and R2 in formula I are both nydroxymethyl, R3 is a direct bond, alkylene of 1 to 6 carbon atoms, oxa-alkylene of 2 to 6 carbon atoms, thialkylene of 2 to 6 carbon atoms, S-oxothiaalkylene of 2 to 6 carbon atoms, S,S-dioxathiaalkylene of 2 to 6 carbon atoms, phenylene, diphenylene or a -phenylene-T-phenylene group, or both substituents R2 together with R3 and both carbon atoms to which these substituents are attached form a cyclopentane or cyclohexane ring, R4 represents alkyl of 1 to 12 carbon atoms, alkyl of 2 to 4 carbon atoms which is substituied by -OH or -Oalk, or represents allyl, cyclohexyl, phenylalkyl of 7 to 9 carbon atoms, phenyl or phenyl which is substituted by Cl, alk, OH, -Oalk or -COOalk, R5 represents alkyl of 1 to 12 carbon atoms, alkyl of 2 to 4 carbon atoms which is substituted by -OH or -Oalk, or represents allyl, cyclohexyl or phenylalkyl or 7 to 9 carbon atoms, or together with R4 represents alkylene of 4 to 5 carbon atoms which can be interrupted by -O- or -Nalk-, or, in the case of compounds of the formula I, together with R2 represents alkylene or phenylalkylene of 1 to 9 carbon atoms or oxaalkylene or azaalkylene of 2 to 3 carbon atoms, R6 represents hydrogen, alkyl of 1 to 12 carbon atoms, alkyl of 2 to 4 carbon atoms which is substituted by -OH or -Oalk, or represents allyl, cyclohexyl, benzyl, phenyl or phenyl which is substituted by Cl or alk, R7 and R8 are the same or different and represent alkyl of 1 to 4 carbon atoms or phenyl, R10 represents alkyl of l to 8 carbon atoms, cyclohexyl or benzyl, ancl R11 represents alkylene of 2 to 8 carbon atoms, xylylene, phenylene or a -phenylene-T-phenylene group; with the proviso that if, in formula I n is 1, and Ar is phenyl, or phenyl substituted by Cl, Br, alkyl, alkoxy or dialkylamino and X is OH or alkoxy, then R1 and R2 are not unsubstituted alkyl.

2. A process according to claim 1, wherein n is 1 or 2, Ar in formula I, if n is 1, and in formula II and III represents C6-C14-aryl which is unsubstituted or substituted by one or more members selected from the group consisting of Cl, Br, alk, -Oalk, -Ophenyl, -COOalk, -N(Alk)2 or NHCOalk and alk represents a lower alkyl radical of 1 to 4 carbon atoms, and, if n is 2, represents C6-C12arylene or a -pheny-lene-T-phenylene group, X represents one of the groups -NR4R5 or -OR6, X' represents one of the groups or -N(R10)-R11-N(R10)-, Y
represents a direct bond or -CH2- Z represents -O-, -CH2- or -C(CH3)2-, T represenls -O- or CH2-, R in formula I, if n is 1 and X is -OR6, re-presents C1-C8 alkyl which is unsubstituted or substituted by -COOaik or CN, or represents C7-Cgphenylalkyl, and in all other cases represents C1-C8alkyl which is unsubstituted or substituted by -OH, Oalk, -COOalk or -CN, or is C7-Cgphenylalkyl, R2 has one of the meanings assigned to R1 or is allyl or a -CH2CH2R13 group, or together with R1 represents C4-C6alkylene or C3-C4oxa- or azaalkylene, R3 represents a direct bond or C1-C6alkylene or together with both substituents R2 and both carbon atoms to which these substituents are attached forms a cyclopentane or cyclohexane ring, R4 represents C1-C12alkyl, C2-C4alkyl which is sub-stituted by OH or Oalk or represents allyl, R5 represents C1-C12alkyl, C2-C4allcyl which is substituted by OH or Oalk or represents allyl or together with R4 represents C4-C5alkylene which can be interrupted by -O- or -Nalk-, R6 represents hydrogen, C1-C12alkyl, C2-C6alXyl which is substituted by OH or Oalk, or is allyl, benzyl, phenyl, or together with R1 represents C3-C4alkylene or -CH2-O-CH2-, R10 represents C1-C8alkyl, R11 represents C2-C8alkylene and R13 represents -CONH2, -CONHalk, -CON
(alk)2, -P(O) (Oalk) 2 or 2-pyridyl, provided that, if in formula I n is 1 and Ar is phenyl or phenyl substituted by Cl, Br, alkyl, alkoxy or dialkylamino and X is OH or alkoxy, R1 and R2 is not unsubstituted alkyl.

3, A process according to claim 1, wherein a compound of the formula I, II or III is employed, wherein n is 1 or 2, Ar in formula I, if n is 1, and in formula II and III represents C6-C14-aryl which is unsubstituted or substituted by Cl, Br or Oalk and alk represents a lower alkyl radical of 1 to 4 carbon atoms, and Ar in formula I, if n is 2 represents C6-C12arylene or a -phenylene-T-phenylene group, X rep-resents one of the groups -NR4R5 or -OR6, X' represents the group , T represents -O- or CH2-, R1 represents C1-C8alkyl, R2 rep-resents -C1-C8alkyl or allyl, R3 represents a direct bond or C1-C6 alkylene, R4 represents C1-C12alkyl, R5 represents C1-C12alkyl or to-gether with R4 represents C4-C5alkylene which can be interrupted by -O- or -Nalk- and R6 represents hydrogen, C1-C12alkyl, C2-C4alkyl which is substituted by OH or Oalk or represents allyl, benzyl, phenyl, pro-vided that, if in formula I n is 1 and Ar is phenyl or phenyl substituted by Cl, Br, alkyl, or alkoxy or dialkylamino and X is OH or alkoxy,R1 and R2 is not unsubstituted alkyl.

4 A proccss according to claim 1, wherein a compound of the formula I is employed, wherein n is 1 and X is OH, R1 and R2 together represent alkylene of 4 or 5 carbon atoms.

S. A process according to claim 1, wherein a compound of the formula I is employed, wherein n is 2.

6. A process according to claim 1, wherein a compound of form-ula II or III is employed, wherein Ar, R1, R2, R3, X and X' are as de-fined in claim 2.

7. A process according to claim 1, wherein a compound of the formula I or II is employed, wherein represents alkyloxy, C1-C6 hydroxy- or alkoxyalkoxy, benzyloxy or phenyloxy.

8, A process according to claim 1, wherein a compound of the formula I, II or III is employed, wherein Ar represents p-phenoxy-phenyl.

9. A process according to claim 1, wherein the photosensitizer is l-benzoyl-cyclohexanol.

10. A photopolymerisable system consisting of at least one un-saturated photopolymerisable compound and 0.1 to 20% by weight of a compound of the formula I, II, III or IV of claim 1 as photosensitizer, and if desired, further known and conventional ingredients.

11. A photopolymerisable system, according to claim 10, wherein the content of the compound of formula I, II, III or IV is from 0.5 to 5% by weight.

12. A photopolymerisable system according to claim 10 or 11, which contains one or more esters of acrylic or methacrylic acid as unsaturated compound.

13. A photopolymerisable system according to claim 10 or 11, which is a printing ink.

14. A photopolymerisable system according to claim 10 or 11 wherein the photosensitizer is l-benzoyl-cyclohexanol.