Note: Descriptions are shown in the official language in which they were submitted.
Sens_tizers for photop_ly~erisation
The invention relates to the use of aromatic aliphatic ketones w~lich
are substituted in the ~-position as sensitizers for the photopolymerisation of
unsaturated compvunds or for the photochemical crosslinking of polyolefins, as
well as to the photopolymerisable and crosslinkable systems which contain such
sensitizers.
Photochemical polymerisation processes have attained substantial
importance in the art, especially in those cases where thin layers have to be
hardened in a short time, for example in the hardening of varnish coatings or in
the drying of printing inks. Compared with conventional hardening methods, W
irradiation in the presenoe of photosensitizers has a number of advantages, the
most important of which is the great speed of the photohardening. The speed is
heavily de~endent on the photosensitizer employed and there has been no lack of
attempts to replaoe the conventional sensitizers by ever better and m~re effec-
tive compounds. AmDng the most effective photosensitizers are derivatives of
benzoin, in particuLar ~le benzoin ethers described for example in German patent
speci~ication
~ ~L
.,~""~,
'~
<3~
2 --
1,694,149, derivatives of a-hydroxymethylbenzoin described
in German Offenlegungsschrift 1,923,266, and the dialkoxy-
acetophenones and benzil monoketals aescxibed for example
in German Offenlegungsschrift 2,261,383 or 2,232,365.
~-Aminoacetophenones and a-diaminoace-tophenones have re-
cently been proposed as photosensitizers in US patent spe-
cification 4,084,034 and a-hydroxy-a-alkylolacetophenones
and their ethers in German Offenlegungsschrift 2,357,866.
The shortcomings of these known photosensitizers are in
some cases an insufficient storage life in the dark of the
photopolymerisable systems mixed with such sensitizers. A
number of benzoin derivatives tend to cause yellowing of
the hardened compositions. Other sensitizers are insuffi-
ciently reactive - a feature which is observed in the rela-
tively lengthy hardening times - or their solubility in the
photopolymerisable systems is too low or they are rapidly
rendered inacti~e by atmospheric oxygen. There is therefore
a need in the art for photosensitizers which are readily
soluble in the substrate and, while having a good storage
life in the dark, initiat0 the photopolymerisation more
rapidly and give a higher polymer yield per unit of time
than the known photosensitizers. By using such improved
photosensittzers it would be possible to exploit better the
expensive industrial UV irradiation plants.
It has been found that compounds of the following
formulae I, II, III and IV possess the re~lired properties
as photosensitizers. In particular, they effect a rapid
photopolymerisation and do not have the shortcomings
referred to or possess them to a much lesser degree than
the known photosensitizers. Furthermore, they are suitable
for the photochemical crosslinking of polyolefins. The
invention relates to the use of the compounds of the for-
mulae I, II, III or IV
~.~429~
O Rl
Ar ~ C - C - X]
12 n
O X X O
Il 1 3 1 11
Ar - C - C - R C - C - Ar II
2 12
O R Rl O
11 1 1 11
Ar C - C - X' - C - C - Ar III
12 ¦ -.
o
~o
¦¦ I ` x IV
wherein n is 1 cr 2, Ar in formula I, if n is 1, and in formulae
II and III, represents C6-C]4 aryl which is unsubstituted or
substituted by one or more members selected from the group
consisting of Cl, Br, CN, OH, Cl-C12alkyl, -Oalk, -Ophenyl, -Salk,
-SCH2CH20EI, Sphenyl, -SO2alk, -SO2phenyl, -COOalk, -SO2NH2,
2 )2~ NHalk, N(alk)2, -NHCOalk
or represents thienyl, pyridyl, furyl, indanyl or -tetrahydronaph-
thyl, 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, a
-phenylene-T-phenylene group or a divalent 9,10-dihydroanthracene
radical, X represen-ts one of the groups -NR4R5, -oR6, -oSiR (R )2
or toge-ther with Rl represents a -o-CH(R9)-, -O-CH(R9)-0-(CH2)1 2-
or -O-Cl-C4alkylene group, X' represents one of -the groups -NR10-,
N(C6 C14arYl) '
-- 3 --
-- 4 --
-N ~ -~ -N(RlO)-Rll-N(Rlo)-~ -Q-, _o_R12_o_, -O-SiR7R8-O-
or -O-SiR R -O-SiR R -O-, Y represents a direct bond or
-CH2-, Z represents -O~, -S-, -SO2-, -CH2-, or -C(CH3~2-,
nt5 -O- -S-, -SO2-~ -CH2-' CH2C 2 6 2 2
-CH=CH-, R in formula I, if n is 1 and X is -OR , repre-
sents Cl-C~alkyl which is unsubstituted or substituted by
C~-C8acyloxyj -NR R , -COOalk or CN, or represents C3-C5
alkenyl, C5-C6cycloalkyl or C7-Cgphenylalkyl, and in all
other cases represents Cl-C8alkyl which is unsubstituted or
substituted by -OH, Oalk, C2~C8acyloxy, -NR R , -COOalk or
-CN, or is C3-C4alkenyl, C5-C6cycloalkyl or C7-Cgphenyl-
alkyl, R has one of the meanings assigned to R or re-
presents a -CH2CH2R 3 group, or together with R represents
C2-C~alkylene or C3-Cgoxa- or azaalkylene, R represents a
direkt bond, Cl-C6alkylene, C2-C6oxaalkylene, C2-C6thia-,
s~oxathia- or S-dioxothiaalkylene, phenylene, diphenylene
or a -phenylene-T-phenylene group, or together with both
substituents R and both carbon atoms to which these sub-
stituents are attached, forms a cyclopentane, cyclohexene,
endomethylenecyclohexane or cyclohexane ring, R4 represents
Cl-C12alkyl, C2-C~alkyl substituted by -OH, Oalk or -CN
or represents C3-C5alkenyl, cyclohexyl, C7-Cgphenylalkyl,
phenyl or phenyl which is substituted by Cl, alk, OH, Oalk
or -COOalk, R represents Cl-C12alkyl, C2-C4alkyl which ls
substituted by OH, Oalk or CN or represents C3-C5alkenyl,
cyclohexyl or C7-Cgphenylalkyl, or together with ~ re-
presents C4-C5alkylene which can be interrupted b~ -O- or
-NR , or, in the case of compounds of the formula I, to-
gether with R represents Cl-C~alkylene or phenylalkylene
or C2-C3oxa- or azaalkylene, R represents hydrogen,
Cl-C12alkyl, Cl-C8alkyl which is substituted by Cl, Br, OX,
Oalk, Salk, C2-C8acyloxy, -COOalk, -CONHalk, -CON(alk)2 or
CN, or represents C3-C5alkenyl, cyclohexyl, benzyl, phenyl
which is unsubstituted of substituted by Cl or alk, or
:,
9~YI
2-tetrahydropyranyl, R7 and R are the same or différent
and represent C1-C4alkyl or phenyl, R represents hydrogen,
Cl-C8alkyl or C6-C~aryl, R represents Cl-C8alkyl, cyc]o-
hexyl or benzyl, R represents C2-C8alkylene, xylylene,
phenylene or a -phenylene-T-phenylene group, R represents
C2-C8alkylene, C~-C6oxaalkylene or xylylene, R represents
-CONH2, -CONHalk, -CON(alk)2, -P(O)(Oalk)2, Z-pyridyl or
2-oxo-1-pyrrolidinyl, R represents cl-C4alkyl~ -CH2CH2CN
or -CH2CH2COOalk, as sensitizers for the photopolymerisa-
tion of unsaturated compounds and for the photochemical
crosslinking of polyolefins.
These compounds are accordin~ly aromatic-alipha-
tic ketones, the a-carbon atom of which is tertiary and
which are substituted by a hydroxyl or amino yroup or the
etherification or silylation products thereof. The alipha-
tic residue can also be cycloaliphatic or araliphatic or
linked to the aromatic residue with ring closure, which
corresponds to the benzocyclic ketones of the ~ormula IV.
Of the substituents listed above, R1, R2, R9 and
R10 can be alkyl of 1 to 8 carbon atoms, for example
methyl, ethyl, propyl, bu~yl, hexyl or octyl. R , R and
R6 as alkyl can be unbranched or branched alkyl of 1 to 12
carbon atoms, for example methyl, ethyl, isopropyl, tert-
butyl, isoamyl, n-hexyl, 2-ethylhexyl, n-decyl or n-
dodecyl. Alk represents a lower alkyl radical of 1 to ~
carbon atoms, for example methyl, ethyl, isopropyl, n-butyl
or tert-butyl.
Rl, R2 and R6 as hydroxyalkyl, alko~yalkyl or
acyloxyalkyl can be for example hydroxymethyl, 1-hydroxy-
ethyl, 2-hydroxyethyl, 2-isopropoxyethyl, l-hydroxyiso-
butyl, l-acetyloxybutyl, l-acryloyloxyhexyl, l-hydroxy-
~7~
octyl, 3-benzoyloxypropyl, methoxymethyl or isobutyloxy-
methyl. The acyl radical can be the radical o~ an alipha~ic
or aromatic carboxylic acid. Preferably they are l-hydroxy-
alkyl radicals and their ethers or esters. R and R as
hydroxyalkyl or alkoxyalkyl can be for example 2-hydroxy-
ethyl, 2-butoxyethyl, 2-methoxypropyl, 3-hydroxypropyl or
2-ethoxybutyl. Preferably they are 2-hydroxyalkyl radicals
and the ethers thereof.
Rl and R as alkyl which is substituted by
-NR4R5 can be for example dibutylaminomethyl, 2-piperidino-
ethyl or 2-dimethylaminopropyl.
Rl, R , R , R or R as CN-substituted alkyl can
be for example 2-cyanoethyl, 2-cyanopropyl or 4-cyanobutyl-
whilst Rl, R2 and R4 can also be for example cyanomethyl,
2-cyanohexyl or 4-cyanooctyl. The 2-cyanoethyl radical is
preferred.
Rl, R2 and R6 as alkyl substituted by -COOalk
can be for example -CH2COOC2H5, -CH2CH2COOCH3, -(CH2)3-
COOCH3 or -CH2CH(C2H5)-COOC~Hg. R6 as alkyl substitute~
by -CONHalk or -CONH(alk)2 can be for example -CH2CONHCH3,
~CH2CH2CON(CH3)2 or -CH2CH(CH3~-CONHC4Hg.
Rl, R , R , R and R as alkenyl can be for
example allyl, methallyl or 2-butenyl.
Rl and R2 as cycloalkyl can be cyclopentyl or
cyclohexyl. Rl, R , R and R as phenylalkyl can be for
example benzyl, phenylethyl or dimethylbenzyl.
Ar as aryl or substituted phenyl can be Eor
example phenyl, naphthyl, phenanthryl, anthracyl, diphenyl-
yl, chlorophenyl, bromophenyl, dichlorophenyl, mesityl,
/
~f~2~9
isopropylphenyl, phenoxyphenyl, cyanophenyl, p-nonylphenyl,
hydroxyphenyl, tolyl, tert-butylphenyl, xylyl, isoprop~l-
chlorophenyl, methoxyphenyl, ethoxyphenyl, phenoxyphenyl,
chlorotolyl, bromoxylyl, methylthiophenyl, phenylthio- -
phenyl, butylsulfophenyl, phenylsulfophenyl, ethoxycarbo-
nylphenyl, tert -butoxycarbonylphenyl, methylaminosulfo-
phenyl, dipropylaminosulfophenyl, dimethylaminophenyl,
benzoylaminophenyl or acetylaminophenyl.
R as aryl can be for example phenyl, tolyl,
naphthyl, diphenylyl or phenanthryl.
Rl and R together can represent alkylene or oxa-
alkylene or azaalkylene. In this case, Rl and R together
with the carbon atom to which they are attached form a
cyclopropane, cyclobutane, cyclopentane, cyclohexane,
cycloheptane, tetrahydrofurane, tetrahydropyrane, pyrroli-
dine or piperidine ring.
~ and R together can represen~ alkylene or
phenylalkylene o~ 1 to 9 carbon atoms or oxaalkylene ox
azaalkylene. In this case, R2 and R5 together wlth the
carbon atom to which R2 is attached and the nitrogen atom
to which R is attached form a 3- to 6-membered ring, for
example an aziridine, azetidine, pyrrolidine, imidazolid-
ine, piperidine, piperazine or morpholine ring.
R4 and R together can represent alkylene of
4 to 5 carbon atoms which can be interrupted by ~0- or
-NRl -. In this case, R and ~ together with the nitrogen
atom to which they are attached form a pyrrolidine, piperi-
dine, morpholine, 4-alkylpiperazine, 4~cyanoethyl-
piperazine or 4-alkoxycarbonylethylpiperazine ring.
-- 8 --
X and R together can represenk a -O-CH~R )-,
-O-C~15R )~O-(CH2)1 2- or -O Cl-C4alkylene group. In this
case, Rl and X together with the carbon atom to which they
are attached form an oxirane, oxetane, oxalane, tetra-
hydropyrane, 1,3-dioxolane or 1,3-dioxane ring which can
be substituted by alkyl or aryl.
~ 3 can be alkylene of 1 to 16 carbon atoms and
R and Rl can be alkylene of 2 to 8 carbon atomsO
Examples of such alkylene groups, within the stated number
of carbon atoms, are: methylene, 1,2-ethylene, 1,3-propyl-
ene, 1,4-butylene, 2,2-dimethyl-1,3-propylene, 1,6-hexyl-
ene, 2-methyl-3-ethyl-1,4-butylene or 1,8-octylene. R3 can
also be oxaalkylene, thiaalkylene and mono- or dioxothia-
alkylene 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-
l,S-pentylene, -C~2SCH2-, -CH2CH2SOCH2CH2- or -
-(CH2)3-S02-(cH2)3
Ar can be arylene 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 ~ is C~2, they are derlvatives of
tetralone, chromanone or thiochromanone.
A particular object of the invention is the use
of compounds of the formula I or II, wherein X is a -NR R
group. These compounds are arylalkyl ketones which are
branched at the ~-carbon atom and substituted by amino
groups.
A further particular object of the invention is
.~ .,
~z~
- 9 -
the use of compounds of the formula I or II, wherein X re-
presents a _oR6 group. These compounds are arylalkyl
ketones which are branched in the ~-position and substi-
tuted by hydroxyl or ether groups.
Yet a further object of the invention is the use
of compounds of the formula I or II, wherein X represents
a -OSiR (R8)2 group. These compounds are aralkyl ketones
which are branched in the ~-position and substituted by
siloxy groups. The -OSiR (R )2 group is for example tri-
meth~lsiloxy, dimethylphenylsiloxy, methyldiphenylsiloxy
or triphenylsiloxy.
Preferably, the in~ention is concerned with the
use of compounds of the formulae I, II, III or IV, wherein
n is 1 or 2, Ar, if n is 1, represents C6-C14aryl which is
unsubstituted or substituted by one or more members se
lected from the group consisting of Cl, Br, Cl-C12alkyl,
-Oalk, -Ophenyl, -COOalk, -N(alk)2 or -NHCOalk, or repre-
sents indanyl, or tetrahydronaphthyl, and alk represents
a lower alkyl 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 NR R or ~OR , X'
represents one of the groups -N~N-, -N(R10)-Rl -N(R10)-
or -O-R 2_o, Y represents a direct bond or CH2-, Z
represents -O-, -CH2 or -C(CH3)2-, T represents -O-, -CH2-
or -CH2C~2-, Rl in formula I, if n is 1 and X is -oR6,
represents Cl-C8alkyl which is unsubstituted or substi-
tuted by -COOalk or CN, or represents C7-Cgphenylalkyl,
and in all other cases represents Cl-C8alkyl which is un-
substituted or substituted by -OH, Oalk, -COOalk or -CN,
or is C7-C~phenylalkyl, R has one of the meanings assigned
to R or is C~-C4alkenyl or a -C~2CH2R group, or to-
gether with R represents C2-~6alkylene or C3-C'4oxa- or
azaalkylene, R represents a direct bond or Cl-C6alkylene
-- 10 --
or together with both substituents R and both carbon atoms
to which these substituents are attached fcrms a cyclo-
pentane or cyclohexane ring, R represents Cl-C12alkyl,
C2-C4alkyl which is substituted by OH, Oalk or CN or re-
presents C3-C5alkenyl, P~ represents Cl-Cl2alkyl, C2-C4-
alkyl which is substituted by OH, OalK or CN or represents
C3-C5alkenyl, or together with R represents C4-C5alkylene
which can be interrupted by -O- or -NR14, R represents
hydrogen, Cl-C12alkyl, Cl-C6alkyl which is substituted by
Cl; Br, OH, Oalk, -COOalk or CN, or is C3-C5alkenyl, benz-
yl, phenyl, or together with R represents C~-C4alkylene
or -CH2-O-CH2-, R represents Cl-C8alkyl, R represents
C2-C~alkylene, R represents C2~C8alkylene, C4-C6oxa-
alkylene or xylylene, R represents -CONH2, -CONHalk',:
-CON(alk)2, -P(O)(Oalk)2 or 2-pyridyl, and R14 represents
Cl-c4alkyl~ -CH2CH2CN or -CH2CH2-COOalk-
Among these compounds, preferred compounds arethose of the formula I, especially those compounds of the
formula I in which n is 1 and X is OH and Rl and R to-
gether represent C2-C5alkylene.
Most preferably, the invention :Ls concerned wlth
the use of compounds o~ the formulae I, II or III, whereln
n is 1 or 2, Ar, if n is l, represents C6-C14aryl which
is unsubstituted or substituted by halogen, Cl-Cl2alkyl or
Oalk, or represents indanyl or tetrahydronaphthyl, and alk
represents a lower alkyl radical of 1 to 4 carbon atoms,
and, if n is 2, represents C6-Cl2arylene or a -phenylene-T-
phenylene group, X represents one of the groups -NR R or
-OR , X' represents one of the groups - ~ - or -o-Rl2_o ,
T represents -O-, -CH2- or -CH2CH2-, R represents Cl-C8-
alkyl, R represents Cl-C8alkyl or C3-C4alkenyl, R re-
presents a direct bond or Cl-C6alkylene, R represents
g4~
-- 11 --
Cl-C12alkyl, R represents Cl-C12alkyl or together with R4
represents C~C5alk~1ene which can be interrupted by -O-
or -NR14-, R represents hydrogen, C1-C12alkyl, Cl-C6alkyl-
which is substituted by OH, Oalk, COOalk or CN, or re-
presents C3-C5alkenyl, benzyl, phenyl, or together with R2
represents -CH2-O-CH2-, R represents C2-C8alkylene and
R represents c1-c4alkYl-
Among these compounds, those compounds o~ theformula I or II are preferred in which X represents allyl-
oxy, Cl-C6hydroxyalko~y or alkoxyalkoxy, -OCH2CH2CN,
-OC~2CH2COOalk, benzyloxy or phenyloxy, or together with
R represents -O-~H2 O-, and also the compounds of the
~ormulae I, II or III in which Ar represents p-phenoxy-
phenyl or a tetrahydronaphthalene radical.
Examples of eligible compounds of the formula I,
wherein n is 1, are: 2-hydroxy-2-methyl-propiophenone,
2~hydroxy-2-ethyl-propiophenone, 2-hydroxy-2-butyl-propio-
phenone, 2-methoxy-2-methyl-propiophenone, 2-hydro~y-2-
methyl-(p-chloropropiophenone), 2-hydroxy-2-methyl-(3,4-
dichloropropiophenone), 2-hydroxy-2-methyl-(p-methoxypro-
piophenone), 2-hydroxy-2-methyl-(2,4-dimethoxypropio-
phenone), 2-hydroxy-2~methyl~-(p-phenoxypropiophenone), 2-
hydroxy-2-methyl-(p-acetylaminopropiophenone), 2-hydroxy-
2-methyl~(p-methylpropiophenone), 2-methoxy-2-methyl-(o-
methylpropiophenone), 2-hydroxy-2-methyl-(m-methylpropio-
phenone), 2-hydroxy-2-methyl-(2,4-dimethylpropiophenone),
2-hydroxy-2-methyl-(3,4-dimethylpropiophenone), 2-hydroxy-
2-methyl-(p-butylpropiophenone), 2-hydroxy-2-methyl-(p-
tert.-butylpropiophenone), 2-hydroxy-2-methyl-(p-isopropyl-
propiophenone), 2-hydroxy-2-methyl-(p-octylpropiophenone),
2-hydroxy-2-methyl-(p-laurylpropiophenone), 2-methoxy-2-
methyl-(o-chloropropiophenone), 2-methoxy-2-methyl-(o-
methylpropiophenone), 2-hydroxy-2-methyl-(p-methylthio-
- 12 -
propiophenone), 2-hydroxy-2-methyl-(p-dimethylaminopropio-
phenone), 2-hydroxy-2-methyl-(p-carboethoxy-propiophenone),
2-phenoxy-2-methylpropiophenone, 2-allyloxy-2 methyl-
propiophenone, 2-benzyloxy-2-methylpropiophenone, 2-(2-
methoxycarbonylethoxy)-2-methyl-propiophenone, 2-(2-cyano-
ethoxy)-2-methyl-propiophenone, 2-ethoxy-2-methylpropio-
phenone, 2-methoxyethoxy-2-methyl-propiophenone, 2-hydroxy-
methoxy-2-methylpropiophenone, 2-hydroxyethoxy-2-methyl-
propiophenone, 2-acetoxymethoxy-2-methylpropiophenone, 2-
benzoyloxymethoxy-2-methylpropiophenone, 2-(o-hydroxy-
phenoxy)-2-methylpropiophenone, 3-benzoyl-3-hydroxyheptane,
2-benzoyl-2-hydroxypentane, 3-benzoyl-3-hydroxypentane, 2-
(2-carboethoxyphenoxy)-2-methylpropiophenone, 2-methyl-2-
piperidino-2-phenyl-3-hydroxypropiophenone, 2-methyl-2-
morpholino-3-phenyl 3-hydroxypropiophenoner 2-methyl-2-di-
methylamino-3-phenyl-3-hydroxy-propiophenone, ~-hydroxy-a-
a-bis-(cyanoethyl)-acetophenone, Y-hydroxy-Y-benzoyl-
pimelate diethylether, 2-hydroxy-2-methyl-3-phenyl-3-di-
methylaminopropiophenone, 2-di-~2-hydroxyethyl)-amino-2-
methyl-3-phenylpropiophenone, 2-methyl-2,3-dipiperidino-3~
phenylpropiophenone, 2,3-bis-(dimethylamino)-3-phenyl-
propiophenone, 2-hydroxy-2,3-dimethyl-3-phenyl-3-dimethyl--
amino-propiophenone, 2-dimethylamino-2-methylpropiophenorle,
2-diethylamino-2-methylpropiophenone, 2-dibutylamino-2-
methylpropiophenone, 2-di-hydroxyethylamino-2-methylpropio-
phenone, 2-piperidino-2-methylpropiophenone, 2-(2-methyl-
piperidino)-2-methylpropiophenone, 2-morpholino-2-methyl-
propiophenone, 2-piperazino~2-methylpropiophenone, 2-(~-
methylpiperazino)-2 methylpropiophenone, 2-~4-carboethoxy-
ethylpiperazino)-2-methyl-propiophenone, 2-pyrrolidino-2-
methylpropiophenone, 2~methylphenylamino-2-methylpropio-
phenone, l-benzoyl-cyclohexanol, l-benzoyl-cyclopentanol,
l-benzoyl-cyclopropanol, 3-p-methoxybenzoyl-3-dimethyl-
aminoheptane, 6-(2-hydroxyisobutyryl)-tetraline, 5-(2-
hydroxyisobutyryl~-indane, 6-(2-dimethylamino-isobutyryl)-
Z9~9
- 13 -
tetraline, 6-(2-morpholino-isobutyryl)-tetraline, 6-(2-
piperidino-isobutyryl)-tetraline, 6-~2-piperazino-iso-
butyryl)-tetraline, 2-(2-methoxybenzoyl)-2-diallylamino-
propane, 2~(2-thenoyl)-2-piperidinopropane, 2-(2-naphthoyl)-
2-acetoxybutane, 2-p-phenylbenzoyl-2-di-(2-hydroxyethyl)-
~ aminopropane, l-methyl-2-o-chloroben~oyl-piperidin, 1-
benzyl-2-benzoyl-3-phenylaziridine, 1-cyclohexyl~2-benzoyl-
3-phenyla~iridine, 2-o-toluyl-2-(trimethylsiloxy)-propane,
: 2-hydroxy-2-methyl-(p-isopropylpropiophenone), 2-hydroxy-
methoxy-2-methyl-propiophenone, 2-hydroxymethoxy-2-methyl-
~2,5-dimethylpropiophenone), 2-hydroxymethoxy-2-methyl-(p-
isopropylpropiophenone~, 5-methyl-5-b~nzoyl-1,3-dioxolane,
2,5-dimethyl-5~benzoyl-1,3-dioxolane, 2-phenyl-5-methyl-5-
benzoyl-1,3-di- xolane, 5-methyl-5-(p-isopropylbenzoyl)-
1,3-dioxolane, 2,3-epoxy-2-methyl-3-phenylpropiophenone,
2-acetoxymethoxy-2-methylpropiophenone, 2-benzoyloxy-
methoxy-2-methylpropiophenone, 2-hydroxy-2-methyl-3-dime-
thylaminopropiophenone, 2-methoxy-2-methyl-3-dimethylamino-
propiophenone, 2-hydroxy-2-methyl~3-morpholinopropio-'
phenone, 2-hydroxy-2-methyl-4-N,N-diethylcarbamoylbutyro~
phenone, 2-morpholino-2-methyl-4-N,N-diethylcarbamoyl-
butyrophenone, 2-hydroxy-2-methyl-4-(2-pyridyl)-butyro-
phenone, 2-hydroxy-2-methyl-4-diethyl-phosphonobutyro-
phenone, 2-hydroxy-2-benzylpropiophenone, 2-hydroxy-2-(p-
methylbenzyl)-propiophenone, 2-hydroxy-2-cyclohexylpropio-
phenone, 2-hydroxy-2-cyclopentylpropiophenone, 2-~2-' .
hydroxyethoxy)-2-methylpropiophenone, 2-hydroxy-2-allyl-
propiophenone, 2-hydroxy-2-methyl-4-~2-oxo-1-pyrrolidinyl)-
butyrophenone, 2-methyIthio-2-methyl-propiophenone.
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, 4,4'-bis-(a-
hydroxy-isobutyryl)-diphenyl methane, 4,4'-bis-(a-piperid-
!~i
- 14 -
ino-isobutyryl~-diphenyl oxide, 4,4'-bis-[a-(isopropyl-
amino)-isobutyryl]-diphenyl, 4,4'-bis-~a-benzoyloxy-iso-
butyryl)-diphenyl oxide, 4,4'-bis-(a-hydroxy-isobutyryl)-
diphenyl ethane.
~ Examples of compounds of the formula II are: 1,4-
diphenyl-2,3-dimethyl-2,3-dihydroxy-butanedione-1,4, 2,4-
dibenzoyl-2,4-dihydroxypentane, 2,9-dibenzoyl-2,9-dimethyl-
3,8-dioxadecane, 2,7-dibenzoyl-2,7-dimethyl-3,6-dioxa-
octane, 1,6-diphenyl-2,5-dimethyl-2,5-dihydroxy-hexane-
dione-1,6, 1,4-diphenyl-2,3-dimethyl-2,3-bis-(dimethyl-
amino)-butanedione-1,4, 1,4-diphenyl-2,3-dimethyl-2,3-di-
piperidyl-butanedione-1,4, 1,2-bis-hydroxy-1,2-bis-benzoyl-
cyclohexane, 1,2-bis-dimethylamino-1,2-bis-benzoyl-cyclo-
hexane, 1,2-bis-morpholino-1,2-bis-benzoyl-cyclohexane,
bis-(3-hydroxy-3-benzoylbutyl)-sulfone.
Examples of compounds of the formula III are:
1,4-b~s-(l-benzoyl-isopropyl)-piperazine, 2,7-dibenzoyl-
2,7 dimethyl-3,6-dioxaoctane, 2,9-dibenzoyl-2,9-dimethyl-
3,8-dioxadecane, 2,6-dibenzoyl-2,6-dimethyl-3,5-dioxahep-
tane, N,N-bis-(a-benzoyl-isopropyl)-butylamine, N,N'-dl.~
methyl-N,N'-bis-(a-benzoyl-isopropyl)-ethylenediarnine.
Examples of compounds of the formula IV are:
1-o~o-2-dimethylamino-2-methyl-1,2,3,4-tetrahydronaphthal-
ene, l-oxo-2-hydroxy-2-m~thyl-1,2,3,4-tetrahydronaphthal-
ene, l-oxo-2-hydroxy-2-methylindane.
Some of the compounds of the formulae I, II, III
and IV are known compoundsl and others are novel.
Known compounds are those of the formula I,
wherein n is l, Ar represents phenyl, phenyl which is sub-
- 15 -
stituted by methyl or methoxy, or is furyl, Rl and R are
methyl or Rl and R2 together represent alkylene and X is
hydroxyl, methoxy or nitrophenoxy.
Xnown compounds are those of the formula I,
wherein n is 1, Ar represents phenyl, chlorophenyl or di~
phenylyl, Rl and R2 are methyl or morpholinomethyl, or
and R together are alkylene and X is a -NR R group, in
which each of R5 and R6 is alkyl or benzyl or R5 and R to-
gether represents alkylene or oxaalkylene.
A known compound is also a compound of the for-
mula II, wherein Ar represents phenyl, R represents me-~ '
thyl, X represents hydroxy and R3 is a direct bond.
The known compounds have up to now not been
proposed as photosensitizers.
The compounds of the formulae I, II, III or IV,
in so far as they are novel, also constitute an object of
the invention. Accordinyly, the invention also relates to:
a) Compounds of the formula I, wherein n is 1, Ar repre-
sentsC10-Cl4aryl~ C6 C14aryl which is substituted by one
ore more members selected from the-group consisting oE CN,
OH, -Ophenyl, -Salk, -SO2alk, -SO2phenyl, -COOalk, ~SO2N~2,
-SO2NHalk~ -SO2N(alk)2, -NHalk or -NHCOalk or represents
thienyl, pyridyl, indanyl or tetrahydronaphthyl, X is OH
or -Oalk, and Rl and R are as previously defined.
b) Compounds of the formula I, wherein n is 1, X is a _oR6
group and R6 represents Cl-C6alkyl which is substituted by
OH or Oalk or represents allyl, cyclohexyl, benzyl, phenyl
which is unsubstituted or substituted by Cl or alk, or to-
gether with R represents C3-C4alkylene or -CH2-O-CH2-,
and Ar, R and R are as previously defined.
~Z9~9
- 16 -
c) Compounds of the formula I, wherein n is 1, X is
-OSiR (R )2 or together with R represents one of the
groups -O-CH(R )-, -O-CH(R )-O-(CH2)1-2- or
-OCl-C4alkylene, R is C2-C4alkyl or phenyl, and Ar, R ,
R and R are as previously defined.
d) Compounds of the formula I, wherein n is 1, Ar is
phenyl, halogenphenyl or diphenylyl, X is a -NR R group,
R is C2~C8alkyl, Cl-C8alkyl which is substituted by OH,
Oalk, C2-C8acyloxy, COOalk or CN, or is C5-C6cycloalkyl
or C -Cgphenylalkyl, R has one of the meanings assigned
to R~ or is llyl or a -CH2CH2Rl group together with R
is C4-C6alkylene or C3-C4oxa- or azaalkylene, and R , R
and Rl are as previously defined.
e) Compounds of the formula I, wherein n is 1, Ar is phenyl
which is substituted by CN, OH, alk, Oalk, -Ophenyl, -Salk,
-SO2alk, -SO2phenyl, -COOalk, -SO2NH2, -SO2NHalk,
-SO2N(alk)2, NHalk, -N(alk)2 or -NHCOalk or is naphthyl,
thienyl, pyridyl, furyl, indanyl or tetrahydronaphthyl,
X is a -~R R group and R , R , R and R are as
previously defined.
f) Compounds of the formula I, wherein n is 2 and Ar, X,
Rl and R are as pre~iously defined.
g) Compounds o~ the formula II, wherein R is a direct
bond, X is one of the groups -NR R , -OR , OSiR (R )2'
R6 is Cl-C12alkyl, C2-C4alkyl which is substituted by OH
or Oalk or is allyl, cyclohexyl, benzyl, phenyl which is
unsubstituted or substituted by C1 or alk, and Ar, R , R4,
R5, R7 and R are as previously defined.
h) Compounds of the formula II, wherein R represents Cl-C6
~lkylene, C2-C6oxaalkylene, C2-C6thia-, ~-oxothia- or S-di-
oxothiaalkylene, phenylene, diphenylene or a -phenylene-T-
phenylene group, and Ar, R , X and T are as previously
defined.
- 17 -
i) Compounds of the formula III, wherein Ar, R , R and X'
are as previously defined.
k) Compounds of the formula IV, wherein R , X, Y and Z are
as previously defined.
These novel compounds can be prepar~d by methods
analogous to those for obtaining the known compounds,
whereby different methods are possible.
Accordingly, the compounds of the formula I can
be prepared from aromatic-aliphatic ketones by the follow-
ing reaction steps:
Ar ~ CO-CHRlR2] ~ A ~ CO CBrR1R2] CH30Na _~
n ~ n
As HX it is possible to use amines [C.L. Stevens,
Ch. Huny Chany, J. Org. Chem. 27 (1962), 4392] or water or
carboxylic acids [C.L. Stevens, E. Farkas, J. Am. Chem.
Soc. 74 (1952), 618 and C.L. Stevens, S.J. Dykstra, J. Am.
Chem. Soc. 75 (1953), 5976].
In many cases the direct reaction of the a-bromo~
ketones to give compounds of the formula I
O R
~r E co CBrR R ~ R
g ~ ~
- 18 -
is also possible, for example with amines, alkal!ihydroxides
or alkali phenoxides. Instead o~ bromine compounds it is
also possible to use the corresponding chlorine compounds.
-
The resulting hydroxyketones of the formula I(X=OH) 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 H-X'-H instead
of the monofunctional compound HX in the above reactions.
The compounds of the formula II can be prepared
analogously to those of the formula I by using diketones
of the generaI formula
Rl 2 R2
Ar- CO - CH~ R - CH -CO - Ar
i The compounds of the formula IV are obtained in
analogous manner starting rom cyclic ketones of the formu-
la
Rl
~7,~,Z,~b
Compounds of the formula I, wherein R is a sub-
stituted alkyl group, can be obtained from the compounds
of the formula Ar~CO-CH(R2)-X]n by reaction with aldehydes
(Rl = hydroxyalkyl) or with a vinyl compound which is cap-
able of addition, for example with acrylated or acrylonit-
rile, In the same way, a -CH~CH2-R13 group can be intro-
duced as R , starting from a compound Ar~CO-CH(R ~~X]n. If
both R and R are substituted alkyl, then both substi-
~s~'j
g
-- 19 --
tuents can be introduced jointly by reaction of a compoundAr~C0-CH2-X]n with at least 2 moles of an aldehyde or a
vinyl compound. The corresponding alkoxyalkyl and acyloxy-
alkyl groups can be obtained from the hydroxyalk~l groups
Rl and/or R by etherification or esterification. Compounds
of the formulae II, III and IV containing substituted alkyl
groups as R or R can be obtained in analogous manner.
Compounds in which X together with R is a -0-CH
(R9) group are a-oxydoketones and can be obtained by epoxi-
-- dation of the corresponding a-vinyl ketones. Reaction of
the oxydoketones with secondary amines affords compounds
in which either X is 0~ and Rl is an aminoalkyl group, or
in which X is N~4R and Rl is a hydroxyalkyl group.
Addition of bromine to the a-vinyl ketones yields
a,~-dibromoketones of the formula Ar~C0-CBr(R ) CBralk~n.
Reaction of the dibromoketones with one mole of
a primary amine yields the corresponding ~-aziridinoketones
[J. Chem. Soc. 65 (1943), 312~, and reaction with 2 moles
o~ a secondary amine yields compounds of the formula I,
wherein ~ is -NR R and R is an aminoalkyl radical ~J. Am.
Chem. Soa. 74 (1952), 1886].
Aminoalkyl groups Rl and/or R can also be intro-
duced by the Mannich reaction, wherein ketones of the for-
m~la Ar~C0-CHR ~X]n or Ar~C0-CH2-X]n are reacted with 1 or
2 moles of formaldehyde and a secondary amine.
Whereas all these methods of synthesis start
from an aromatic-aliphatic ketone into which a substituent
X is introduced in a different manner, it is also possible
in specific cases to introduce the substituent X during the
ketone synthesis by the Friedel-Crafts reaction in accor-
'
~ 20 -
dance with the reaction scheme:
Rl R
I AlC13
X-C-COC1 + ArH ~ Ar-CO-C-X
R2 12
rrhis presupposes that the substituent X is not
attacked under the conditions o the Friedel-Crafts reac-
tion. In this way it is possible for example by using
heterocyclic carboxylic acid chlorides to prepare compounds
of the formula I, in which X and Rl together with the car-
bon atom to which they are attached form a heteroring.
.
According to the invention, the compounds o~ the
~ormulae 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 mono-
mers, such as esters of acrylic or methacrylic acid, for
example methacrylate, ethylacrylate, n- or tert-butyl~
acrylate, isooctylacrylate or hydro~yethylacrylate, methyl-
or ethylmethacrylate, ethylene diacrylate, neopentyl di-
acrylate, trimethylolpropane trisacrylate, pentaerythritol
tetraacrylate or pentaerythritol trisacrylate; acrylo-
nitrile, methacrylonitrile, acrylamide, methacrylamide,
N-substituted acrylamides and methacrylamides; vinyl
esters, such as vinyl acetate, vinyl propionate, vinyl
acrylate or vinyl succinate; other vinyl compounds, such
as vinyl ethers, styrene/ alkyl styrenes, halostyrenes,
divinyl benzene, vinyl naphthalene, N-vinylpyrrolidone,
vinyl chloride or vinylidene chloride; allyl compounds,
such as diallyl phthalate, diallyl maleate, triallyl iso-
cyanurate, triallyl phosphate or ethylene glycol diallyl
ether and the mixtures of such unsaturated monomers.
~L~4Z~9
- 21 -
, Photopolymerisable compounds are in addition un~
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, allyl groups or acrylate or methacrylate
groups. These unsaturated groups are usually bound through
functional groups to the main chain of these linear poly-
mers~ Mixtures of oligomers with simply and poly-unsatu-
rated monomers are ~ery important. Examples of such
oligomers are unsaturated polyesters, unsaturated acrylic
resins and isocyanate or epoxide modified acrylate oligo-
mers as well as polyether acrylate oligomers. Examples of
poly-unsaturated compounds are in particular the acrylates
of diols and polyols, for example hexamethylene diacrylate
or pentaerythritol tetracrylate. Acrylates are also
preferred as simply unsaturated monomers, for example
butyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethyl-
hexyl acrylate or 2-hydroxypropyl acrylateO By choosing
rom the diferent representatives of the three component$,
the opportunity is afforded to vary the consistency of
the unpolymerised mixture as well as the plasticity of
the polymerised resin.
In addition to these three-component mixtures,
two-component mixtures especially are of great importance
among the polyester resins. These usually consist of an un-
saturated po]yester and a vinyl compoundO The unsaturated
polyesters are oligomer esterification products of at
least one unsaturated dicarboxylic acid, for example
maleic, 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
glycols, for example ethylene glycol, propanediol~l,2, di-
or triethylene glycol or tetramethylene glycol, whilst
monocarboxylic acids and monoalcohols are generally also
2~
- 22 -
used concurrently for the modification. These unsaturated
polyesters are normally dissolved in a vinyl or allyl com-
pound, styrene 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 photosensitizeri a
number of other ingredients. It is therefore often
customary to add heat inhibitors in order to prevent a
premature polymerisation, especially during the preparation
of the systems by mixing the components. Hydroquinone,
hydroquinone derivatives, p-methoxyphenyl, ~-naphthylamine
or ~-naphthols are used for example for this purpose.
Furthermore, small amounts o UV absorbers can be added~
for example those o~ the benztriazole or benzophenone type.
To increase the storage life in the dark, it is
possible to add copper compounds, suc~ as copper naph-
thenate, copper stearate or copper octoate, phosphorus com-
pounds, such as triphenylphosphine, tributylphosphine,
triethyl phosphite, triphenyl phosphite or tribenzyl phos-
phate, quaternary ammonium compounds, such as tetramekhyl-
ammonium chloride or, trimethylbenzylammonium chloride,
or hydroxylamine derivatives, for example N-diethylhydrox-
ylamine. In addition, the photopolymerisable systems can
contain chain transfer agents, for example N-methyl-di-
ethanolamine, triethanolamine or cyclohexene.
In order to exclude the inhibiting action of
atmospheric oxygen, paraffin or similar wax-like substan-
ces are ~requPntly added to the photohardening systems.
On account of their poor solubility in the polymer, these
substances float at the beginning of the polymerisation
and form a transparent surface layer which prevents the
entry of air.
Z~9L9
The atmospheric oxygen can also be deactivated h~ introduc-
ing autoxidisable groups, for example allyl 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, fibres, thixotropic agents or
levelling agents.
Combinations with known photosensitizers, such
as benzoin ethers, dia~koxy acetophenones or benzyl ketals,
can also be used. Combinations of the photosensitizers of
the invention with amines and/or aromatic ketones can be
used especially for the photopolymerisation of thin layers
and printing inks. Examples of amines are triethylamine,
N-methyldiethanolamine, N-dimethylethanolamine or p-di-
methylaminobenzoate. Examples of ketones are benzophenone,
substituted benzophenone derivatives, Michler's ketone,
anthraquinone and antraquinone derivatives, as well as
thioxanthone and the derivatives thereof.
Photohardening is of great importance for print-
ing inks, since the dryin~ time of the binder is a
decisive factor in the production speed of printing pro-
ducts and should be in the order of fractions of seconds.
The sensitizers of the invention are also very suitable
for photohardening systems for the manufacture of printing
plates. l~lixtures of soluble linear polyamides with photo-
polymerisable monomers, for example acrylamides, and a
photosensitizer, are usually employed for this purpose.
Films or plates prepared from these systems are exposed
via the negative (or positive) of the original and the un-
hardened portions are subsequently eluted with a solvent.
%~q~9
- 2~ -
A further field of use of UV hardening is metal
coating, for example in the varnish coating of metal
sheeting for tubes, cans or bottle caps, as well as the UV
hardening of pIastic coatings, for example of floor or
wall coverings based on PVC.
Exemplary of the UV hardening of paper coatings
is the colourless varnish coating of labels, gramophone
record sleeves or book jackets.
According to the invention, the compounds of the
formulae I, II, III and IV can also be used as sensitizers
for the photochemical crosslinking 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 photosensitizers 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 photopol~merisable or crosslinkahle system. The term
"system" is to be understood as meaning the mlxture of
the photopolymerisab~e or crosslinkable compound, the
photosensitizer and the other fillers and additives, as
it is used in the respective application.
The addition of the photosensitizers to the
photopolymerisable systems is accomplished in general by
simple stirring, since most of these systems are 1uid or
readily soluble. Usually the sensitizers of the inv~ntion
dissolve in the system, thereby ensuring their uniform
distribution and the transparency of the polymers.
The polymerisation is carried out by the known
methods of polymerisation by irradiation with light which
~!
is rich in shortwave radiation. Suitable light sources are
for e~ample 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 nm.
The following Examples describe the manufacture
and use of compounds of the formula I in more detail. Parts
and percentages are by weight.
- 26 -
~anufacture and properties of the compounds used in
Exam le~ 1 to 6
P ~ ._
The compounds listed in Table 1 where obtained
by one or more of the methods A to L.
Method A Chlorination of aromatic-aliphatic ketones
Ar~CO-CR R H] n + n C12 ~ Ar~Co-CR R Cl]n ~ n HC1
The ketone 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 HCl. Finally, the sol-
vent is distilled off. Purification of the chloroketone is
usually not necessary and the product can subsequently be
reacted by method ~, F or H.
Method B Bromination of aromatic--aliphatic ke-tones
Ae~C0-CR R H]n ~ n Br2 ~ Ar~C0-CR R Br]n + n HBr
The calculated amount of bromine is added dropwise at room
temperature to a solution of the ketone, for example in
CCl~. Working up and further processing are effected as in
Method A.
Method C Chlorination with sulfury.l chloride
Ar~C0-CR R H] n S02 C12 Ar~C0-CR R -Cl~n
+ n S02 + n HCl
The sulfuryl chloride is added dropwise at 40C to a solu-
tion of the ketone in CC14. Working up and further process-
ing as in Method A.
;,
Method D Preparation of the epoxide intermediate
Ar~CO-CR R Hal] ~ n NaOCH3 ---D Ar~CI - CR R ]n ~ n NaHal
Hal = Cl or Br
The haloketone is dissolved in methanol and a solution of
the stoi~hiometric amount of sodium methoxide in methanol
is added dropwise at reflux 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 Na2S04, dried and concentrated. The
residue is purified by recrystallisation or vacuum distil~
lation. The epoxide can subsequently be reacted by Method
E or G.
Method E Hydrolysis of the epoxide
~ 1 2] H+ 1 2
The epoxide is covered with 2 to 5 times its weight of
water and the mixture is refluxed for 1 to 2 hours with
the addition of a catalytic amount of mineral acid. After
cooling, the reaction mixture is extracted with ether. The
ethereal solution is washed with water, dried over Na2SO~,
and concentrated. The residue (crude hydroxyketone) is
purified by distillation or crystallisation or column
chromatography. The properties of the pure a-hydroxyketones
are indicated in Table 1.
Method F a~Hydroxyketones from ~-haloketones
Ar~CO-CR R Hal]n t n NaOH ~ Ar~CO-CR R OH]n ~ n NaHal
The c~-haloketone is refluxed in dilute or concentrated
sodium hydroxide solution 120 % excess of NaOH). When the
49
- 28
hydrolysis is complete Icheck 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 epoxides
Ar~ ~ CR R ] +n R R NH Ar~CO-CR R -NR R ] + n CH30H
The epoxide is treated with the stoichiometric amount of
the amine, either without a solvent or with the addition
of a small amount of toluene or xylene, and reacted for
about lO to 20 hours at 100-200C. When using low boiling
amines, for example dimethylamine or diethylamine, the ~
reaction is carried out in an autoclave. The reaction mix-
ture is diluted with benzene and extracted with dilute
hydrochloric acid. The aqueous acid solution is made
alkaline with NaOH and extracted with ether. The ethereal
solution is washed with water, dried oVer Na2SO~ and con-
centrated. The crude product is purifi.ed by distillation
or crystallisation. The a-amineketones are listed in Table
1.
M hod H a-~ninoketones from the a-haloketones
Ar~CO-CR R Hal~n ~ 2n R R NH ~ Ar~CO-CRlR -NR4R ]
+ n R R NH2Hal
The a-haloketone, undiluted or diluted with toluene, is
mixed with 2 molar equivalents of the amine and the mix-
ture is heated for 10 to 20 hours to 100-200C. When using
low boilingamines, forexample dimethylamine or diethylamine,
the reaction is carried out in an autoclave. Isolation and
2~4~
- 29
purification are effected as in Me-thod G.
Method I Introduction of a carbalkoxyethyl group
C~2C~2COOAlX
ArtCO-CHRl-X]n + n CH2 = CH-COOAlk -~Ar~CO-CP~l-X . ] n
The ketone is dissolved in dimethyl sulfoxide. To the solu-
tion are then added 1.1 molar ecuivalents of NaOH in the
form of 4N sodium hydroxide solution and, with cooling,
1.1 molar equivalents of acrylate are added dropwise at
room temperature. The reaction mixture is diluted with ice-
water and extracted with toluene. The toluene solution is
washed neutral with water, dried over Na2SO~ and concentra-
ted. The crude product is purified by column chromatography
or crystallisation.
Method K Etherification of hydroxyketones
Ar~CO-CR ~ -OH] ~ n R Hal ~ n NaOH Ar~CO-CR R -OR ]
+ n NaHal
The a-hydroxyketone i5 dissolved in about 4 times its weight
of dimethyl sulfoxide and, while cooling to 10-20C and
with stirring, 1 molar equivalent o~ the alkyl halide R6Hal
and 1 molar equivalent of concentrated sodium hydroxide
solution are added dropwise simultaneously from t~o 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 Na2S04 and concentrated. The crude product -is
purified by column chromatography~ crystallisation or
vacuum distillation. Examples of eligible halogen compounds
are melhyl iodide, isopropyl bromide, all~ll bromide, cyclo-
hexyl bromide, benzyl chloride or ethyl chloroacetate.
- 30 -
Instead of using an alkyl halide, it is also possible to use
a dialkyl sulfate or alkylaryl sulfonate as etherifying
reagent.
Method L Cyclisation of X and R
2 2
~r-C0-C'~Hal~R ~ CH20 --~ Ar-C0-CR Hal-CH20~ MaOC~3
Ar-C0- ~ H~ + Na;~al -~ C~30~1
Paraformaldehyde is dissolved in 20 times its weight of
methanol. To the solution is then added l molar equivalent
of sodium methoxide tdissolved in a small amount of methanol).
~hile cooling to 0-5C, a concentrated solution of the
a-haloketone is added dropwise. The reaction mixture is sub-
sequently stirred for l hour at 5-10C and for l 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 Na2S04
and concentrated. The crude product is puriEied by distil-
lation or colurnn chromatography.
-- 3~--
~ ~ . ~ _
u) I ~ ~ ooul I
a r~ ~ S r
1
P~ ~ ~ ~ .
~ _
+
a a c
+ ~ ~ ~
m ~: ~ o m
.
U+~ U+U ut~u \./~0~.
O = C~ O = ~ O ~ ~ C =
~ l l l
\ 0// ~O /,' `~.
o l )l l ll l ll l ll
~I ~ / ~\ / ~ / ~\ /
~ _ . . ~ _ ~ _
a~ 1~
E~ ~ ~ _ ~ _~ .
_ 32
_ _ . , ~ . _ , .
O o O K -K
U~ O O O O
(I) U-) Lt') e~ fr~
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r l r~ O r O O
l~ Q~ r~ ~ Q~ Q~ 5
,~,:, _ ,Q _ _
11~ r~l
. ~ U~ ~ J~ . r
P~ .S ~ r~
_ _ _
O ~ r + ;~ ~sl +
~ ~ m m m m +
_ _ _ _ ___
_O _ o ~ o
! ,~ ,- _ + r~ '~ + ~ r_~ + C)
,~-o- O ~ O = ;) O = C~ O ~
l r~) O ~ /;\ // \ // \ /
O = U C) +.t_~ 1~ 1~ o 9
r~5 ~ \ O = C~ o \~ / \ o o
~ . . t--. . ~ J r_) l
O `~ / o=- r.~ -- ¦ _ j
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1,~ i . ~ : i
rJ 52~ u~ ~D I r_ 0 - G~ !
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_ 34 --
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a
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- 35 _
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~1 0 S~ C~ O ?C ,0 Q~
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Example 1
A resin mixture consisting of 80 parts of Plex* 6616 (acrylate resin,
available from Rohm, Darmstadt), 20 parts of trimPthylolpropane-trisacrylate and
2 parts of photosensitiæer is applied with a film drawing device to glass plates
in a thickness of 40 ~. These films are exposed to air for about 20 seconds and
then irradiated with a mercury medium pressure lamp (Hanovia device, ~del
45080). Irl 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 ne oe ssary in order
to obtain non-tacky films. In additian, the hardness of the filn was determined
with a pendulum devioe by the method of Konig. The final column indicates the
storage stability of the resin-photosensitizer mL~ture in the dark at 60C~
*Trademark - 41 -
.~
2~9
Table 2
_ _ . _
Pendulum hardness accord~ Storage
Photosensitizer Runs ing ~o Konig after stability
number of runs (R) in days
_ ~ _ .
1 4 78(4R) 94(6R) 98(8R) >30
2 4 101(4R) 114(4R) 116(8R) >30
3 4 116(4R) 119(8R) 131(8R) ~30
12 3 95(3R) 101(4R) 103(5R)
24 3 73(5R)
26 3 95(3R) 102~4R) 107(5R) <30
37 4 47(3R) 72(4R) 88(5R) <30
__ _
a-hydroxypro- 3 68(3R) 75(4R) 87~5R)
piophenone
(comparison)
a-methylbenzoin. 5 49(3R) 69(4R) 91(5R)
(comparison)
benzoin-tert- 5 93(5R) 106(7R) 113(9R) <30
butylether
(cc~parison)
2-phenyl-di- 6 112(6R) 121(8R) 130(lOR) ~30
mp~thoxyacetor
phenone
(comparison)
p-met~yl-~,a-di- 8 92(8R)lOO(lOR) 109(12R) <5
morpholinoace-
tophenone
(oomparison)
a,a-dimorpholino- 17 84(17R)98(19R) ~1
aoetophenone
(cJ~mparison)
. _
- 42 -
''.1
~4;2~
Example 2
Resin mixtures consisting of 60 parts of Uvimer* DV-530 (urethane
acrylate, available frQm PolychrGme)~ 37 parts of hexanedioldiacrylate and 3
parts of photosensitizer were applied in a film thickness of 30 ~m to glass
plates and irradiated as described in Example 1. The follcwing results were ob-
tained.
Table 3
_ _ _ . _ _ . _
No. of runs Pendulum hardness
Photo ænsitizer necessary until wipe- according to Konig as
proof a function of R
_ . . .
1 3 129(3R)
157(7R)
2 3 . 144(3R)
163(7R)
diethoxyaoe to- 10 156(lOR)
phenone
(comparison)
benzoin tert- 12 136(12R)
butyl ether
(ccmparison)
2-phenyldi- 8 155(8R)
methoxyaceto-
phenone
(ocmparison) _
__ _
*Trademark 43
Example 3
2% of photosensitizer was dissolved in an unsaturated polyester resin
(Crystic* PKE 306, available from Maeder, Killwangen, Switzerland). These resin
mixtures were applied in a film thickness of 60 ~m to glass plates. The films
were irradiated as d~scribed in Example 1. The number of runs through the expo-
sure device until the films were ~ipe-proof as well as the pendulum hardness as
a function of R are reported in Table 4.
Table 4
. _ _
No. of runs PendNlum hardness
Photosensitizerneoessary until wipe-according to Konig as
proof a function of R
_ _
1 13 21(13R) 34(15R? 62(17R)
2 8 20(8R) 31(lOR) 89(12R)
28(lOR) 71(12R) 109(12R)
*Trademark - 44 -
Example 4
A resin mixture consistiny of 90 parts of Laromer* LR 8496 (acryla~e
resin available from BASF, West Germany), 10 parts of hexanediol diacrylate,
0.5 part of ~yK 300 (levelling assistant available fr~ ByK-Mallinckrodt, West
German~v) and 3 parts of photosensitizer for hardening in the air or 0.5 part of
photos~nsitizer for hardening under nitrogen, is applied electrcmotively to
cardboard boxes with a 15 ~ helix. After brief exposure to air, hardening is
effected with a UV devi oe (model PPG-QC-pro oe sser~ with a W lamp of 80 watts/om.
m~ nE~uumlm transportation speed at which non-tacky films were obtained in air
or under nitrogen is reported in Table 5 in m~min.
Table S
___
.
Photosensitizer Transportation speed (m~min)
air nitrogen
__ ., __
3 20 100
100
7 30 100
8 30 100
9 5 80
12 3,3 80
13 20 120
29 10 90
_ 20 _ 90
*Trademark - 45 -
Example 5
A resin mIxture consisting of 70 part5 of Ebercyl* 593 (polyester
acrylate available from UGB, Belgium), 30 parts of trimethylolpropane trisacry-
late, 0.5 part of ByK 300 (levell mg assistant available from ByK-Mallinckrodt,
West Germany) and 3 parts of photosensitizer, is applied to glass plates in a
layer of 30-40 ~. After brief exposure to air, hardening is effected with a UV
laboratory device (model PPG/QC-processer) with a W lamp of 80 watts/cm. After
the UV har~ening, the plates are stored for 1/2 hour under normal climatic con-
ditions and then the hardness of the layers is determined using the pendulum de-
vioe of gonig. The hardness values as a function of the transportation speedunder the lamp are reported in Table 6.
Table 6
Photosensitizer Pendulum hardness in sec.
10 m~min. 25 m~min.
.
3 154 146
13 156 147
14 138 137
150 132
16 161 152
17 160 1~4
21 155 1~3
22 151 127
27 16~ 154
129 98
32 146 129
134 108
38 139 116
39 162 14~
153 131
41 164 152
_ _. .
*Trademark - 46 -
