PHOTO-SENSITIZING COMPOUNDS IN PHOTO-POLYMERIZABLE SYSTEMS

COMPOSES PHOTO-SENSIBILISATEURS EMPLOYES DANS DES SYSTEMES PHOTOPOLYMERISABLES

English Abstract

Abstract of the Disclosure
The present invention concerns novel photo-
polymerisable formulations which comprise a photo-
polymerisable system in association with photo-
sensitizing amount of the compound of formula
<IMG>
wherein R is an unsubstituted or substituted
binuclear aromatic group, e.g. phenoxy
phenyl,
m is 0, 1 or 2
and Hal is halogen.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A photo-polymerisable formulation which comprises
a photo-polymerisable system in association with from 0.1 to
10% by weight based on the photopolymerisable system of a
compound of formula Ia
<IMG> Ia
in which Hal is chlorine or bromine,
m is 0, 1 or 2,
R' is a radical of formula aa,
<IMG> aa
wherein X1 is a direct covalent bond
or is -0-, -S-, -S0-, -S02-
or <IMG>
and either X2 and X3 are each hydrogen
or,when X1 is a direct covalent
bond, X2 and X3 together may
also form one of the bridge
members -0-, -S-,-S0- or -S02-,
m is 0, 1 or 2,
19

each of R1, R2, R4 and R5 is, independently,
hydrogen or alkyl(C1-C18) with up
to C18 in the aggregate of all of the
the substituents R1, R2, R4 and
R5,
R3 is hydrogen, halogen or a radical
<IMG>
and R6 is -C(H)m(Hal)3-m
wherein Hal and m are as
defined above,
furenyl, thienyl, phenyl or phenyl
substituted by 1 alkyl(C1-C4) or
1 or 2 halogen substituents.
2. A formulation according to Claim 1 in which the
compound of formula Ia is one of formula Ib,
Ib
<IMG>
wherein Hal and m are as defined in Claim 1,
and R" is a radical of formula ab,
ab
<IMG>

wherein R1, R2, R4 and R5 are as defined in Claim 1,
and X? is -0- or -S-.
3. A formulation according to Claim 2, wherein the
radical of formula ab is of formula ab',
<IMG> ab'
wherein R1, R2 and X? are as defined in Claim 2.
4. A formulation according to Claim 2 or 3,comprising
a photo-sensitizing amount of a compound of formula Ic,
<IMG> Ic
wherein X?, Hal and m are as defined in Claims 2 and 3.
5. A formulation according to Claim 1, wherein the
radical of formula aa has one of the ring structures
ac
<IMG>
<IMG> ad
<IMG> ae
21

<IMG> af
<IMG> ag
each of which ls unsubstitued or substituted.
6. A formulation accordlnq to Clalm 5, comprising
a photo-sensitizing amount of a compound of one of the
formulae
<IMG>
<IMG>
<IMG>
<IMG>
<IMG>
<IMG>
22

<IMG>
<IMG>
<IMG>
7. A formulation according to Claim 1, in which
the photo-polymerisable system comprises at least one
multi-functional component to promote photo-initiated
cross-linking.
8. A formulation according to Claim 1,
in which at least one of the components of the photo-
polymerisable system is an unsaturated carboxylic acid
or a derivative thereof.
9. A formulation according to Claim 8, in which
the unsaturated carboxylic acid or derivative thereof is
acrylic or methacrylic acid or a derivative thereof.
10. A formulation according to Claim 1, in which
the photo-polymerisable system is multicomponent and
comprises one or more reactive prepolymers or one or more
reactive long chain monomers, in association with one
or more cross-linking monomers.
11. A formulation according to Claim 10,
in which the one or more reactive prepolymers are selected
23

- 24 -
from the group consisting of unsaturated polyethers,
polyesters, polyester-based urethanes and epoxy resins,
and saturated or unsaturated such polymers modified by
esterification with an unsaturated carboxylic acid.
12. A formulation according to Claim 11, in
which the one or more reactive prepolymers are selected
from the group consisting of acrylated or methacrylated
hydroxy-functional polyethers, polyesters, polyester-based
urethanes, polyester-based epoxy resins and unsaturated
polyesters.
13. A formulation according to Claim 10, in which
the one or more reactive long chain monomers are selected
from the group consisting of acryl derivatives of epoxy-
lated unsaturated fatty acids.
14. A formulation according to Claim 13, in which
the one or more reactive long chain monomers are selected
from the group consisting of acryl derivatives of
epoxylated linseed oil.
15. A formulation according to Claim 10, in which
the one or more cross-linking monomers are selected from
the group consisting of vinyl and allyl monomers, acry-
lated alcohols and multi-functional acrylates.
16. A formulation according to Claim 15, in which
the one or more cross-linking monomers are selected from
the group consisting of styrene, the diallyl ether of
trimethylol propane, vinyl acrylate, diallyl maleate,
24

diallyl phthalate, acrylated phenoxyethyl alcohol, acry-
lated neopentyl glycol and acrylated pentaerythritol.
17. A formulation according to Claim 1, in the form
of an ultraviolet curable coating or printing ink resin
containing no or less than 1% by weight of non-reactive
solvent.
18. A formulation according to Claim 1, in which the
amount of compound of formula Ia is from 0.05 to 5% of the
weight of the photopolymerisable system.
19. A method of photo-polymerising a photo-
polymerisable system which comprises irradiating said
system with ultraviolet light of wave-length 250 to 400
nm in the presence of 0.1 to 10% by weight based on the
photopolymerisable system of a compound of formula Ia as
defined in Claim 1.

Description

1083Z9~
The present invention relates to photo-polymerisable
forml.lation5 and more specifically to such formulations which
include a photo-sensitizing agent to initiate and
accelerate polymerisation on exposure to light.
Accordingly, the present invention provides a photo-
polymerisable formulaticn which comprises a photo-
polymerisable system in association with from 0.1 to 10%
by weight based on the photopolymerisable system of a
compound of formula Ia
o
R' - C - C(H)m(Hal)3_m Ia
in which Hal is chlorine or bromine,
m is 0, 1 or 2,
R' is a radical of formula aa,
Rl R4
R3 ~ Xl ~ aa
R2 R5
wherein xlis a direct covalent bond
or is -O-, -S-, -SO-, -SO2-
CIH3
or -C-
CH3
and either X2 and X3 are each hydrogen
or, when Xl is a direct covalent
bond, X2 and X3 together may
also form one of the bridge
members -0-, -S-, -S0- or SO2-,
-- 2 --
~ ;~

1(~83Z94
m is 0, 1 or 2,
each of Rl, R~, R4 and R5 is,
independently, hydrogen or alkyl
(Cl C18) with up to C18 in the
aggregate of all of the
substituents Rl, R2, R4
and R5,
R3 is hydrogen, halogen or a radical
R6 - C -
and R6 is -C(H)m(Hal)3-m
wherein Hal and m are as
defined above,
furenyl, thienyl, phenyl or phenyl
substituted by 1 alkyl (Cl-C4)
. or 1 or 2 halogen substituents.
As will be appreciated, the selection of substituents
on the radical of formula a forms part of the general :
knowledge in the photo-sensitizer srt.
.
,, '`
'
~3' ` .
:,
.

1~83294
More preferably, the formulation includes as photo
sen~;itizing agent a compound of formula Ib
o
R" - C - C(H)m(Hal)3_m Ib
wherein Hal and m are as defined above
and R" is a radical of formula ab
~ X' ~ ab
R2 R5
~ . ,

108329~
150-3661
whereln Rl, R2, R4 and R5 are as defined above,
and Xl ls -O- or -S-,
more preferably a radical of formula ab'
R
~ i ~ . ab'
R2
wherein Rl, R2 and X; are as defined above.
In particular, the formulation preferably
includes as photo-sensitizing agent a compound of
formula Ic
B ~X ~ C(N)m~Hal)3_m Ic
wherein Xl, Hal and m are as defined above.
By the term halogen is meant chlorine, bromine
or iodine, preferably chlorine or bromine, particularly
chlorine.
When any of Rl, R2, R4 and R5 are alkyl, this
f rablY C -C12, more preferably Cl 8
Cl-C6, and in particular Cl-C4, e.g. methyl. Such
alkyls may be straight or branched chaln, primary,

1083Z9~ 150-3661
secondary or tertiary.
Preferably R4 and R5 are each hydrogen.
R3 is a group " R6 therein is
preferably -C(H)m(Hal)3_m- 0
Preferably R3 is hydrogen or -C-C(H)m(Hal)3 m
especlally hydrogen.
Preferably R3, when a substituent, occupies
a para position in relation to X1 or, when X2 forms
part of a bridge member, to X2.
Preferably the free bond of the radical a
occupies a para position in relation to X1 or, when
X3 forms part of a bridge member, to X3.
Preferably the unsubstituted or substituted
radical of fo~mula a has one of the following ring
structures,
~ - ~ ac
~ 5 ~ . ad
_ ae
0 ~ af

150-3661
~OB3294
aq
partlcularly ac, ad, ae and af, especlally ac
and ad.
The compounds of formula I are generally known.
Insofar as they are not known, they may be produced in
analogous manner to the processes for produclng the
known compounds, e.g. by the Friedel-Crafts reaction.
The present invention also provides a method
of photo-polymerislng a photo-polymerisable system
. ~ ~io~
~ which comprises irradiating said system with~h~ light
of wave length 250f400 nm in the presence of a photo-
sensltlzing amount of a compound of formula I.
It is to be understood that the terms "photo-
polymerlslng" and "photo-polymerisable" are employed
herein in a broad sense to include e.g. cross-linking
of polymeric materials, such materials being referred
to herein as "prepolymers", as well as slmple homo-
co- and terpolymerlsation of monomers.
Any of the conventional light sources provid-
ing light of wave length 250tt400 nm may be employed,
such as sunlight or actinic light from e.g. a sun ray
lamp or mercury arc lamp.
Photo-polymerlsable systems suitable for use

150-3661
101~3Z94
ln the formulations of the present invention are in
general known, e.g. in the ultraviolet curable coating and
pri.nting ink arts. Such sy~tems are preferably those
capable of polymerlslng by a free radlcal mechanism
and ln general the polymerlsing species is/are unsat-
urated. The systems may be mono- or multi-component.
It is preferred that the systems contaln at least one
multl-functlonal component to promote photo-lnltlated
cross-llnking. In addltlon, lt i5 preferred that at
least one component of the system i8 an unsaturated
carboxylic acid or a derivative thereof,ln particular an
a,B-unsaturated carboxylic acld such as acryllc or
methacryllc acld or a derivative thereof.
Preferably the system is multi-component and
more preferably comprlses one or more reactlve prepolymers
or one or more reactlve long chaln monomers ln association
wlth one or more cross-linklng monomers. Preferred reactive
prepolymers are unsaturated polyethers, polyesters,
polyester-based urethanes and epoxy resins, and saturated
or unsaturated such polymers modified by esterification
with an unsaturated carboxyllc acid. Especially preferred
reactive prepolymers'are acrylated or methacrylated
hydroxy-functional polyethers, polyesters, polyester-based
urethanes and epoxy resins, and unsaturated polyesters.
Preferred reactlve long chain.
- 8 -

1~83Z9~
monomers are acryl derivatives of epoxylated unsaturat-
ed fatty acids, especially acryl derivatlves of epoxy-
lated linseed oll. Preferred cross-linking monomers are
vinyl and allyl monomers, e.g. styrene, the diallyl
ether of trimethylol propane and vinyl and allyl esters
such as vinyl acrylate and diallyl maleate and phthalate,
acrylated alcohols, e.g. acrylated phenoxyethyl alcohol,
and multi-functional acrylates e.g. acrylated polyols,
such as acrylated neopentyl glycol and pentaerythritol.
The photo-polymerisable formulations of the present
invention are of particular interest as ultraviolet
curable coatings, e.g. coating lacquers, and printing
inks, e.g. offset lithographic printing inks.
For such use, the formulations are preferably
of resinous form and contain no or minimal ~i.e. less
than 1% by weight) non-reactive solvent. In the case of
multi-component systems comprising a reactive prepolymer
or long chain monomer and at least one cross-linking
monomer, the cross-linking monomer is preferably
selected inter alia in accordance with the solvent
properties thereof to provide the desired viscosity
characteristics for the final formulations.
Other agents, e.g. anti-oxidants, pigments
and fillers, may also be employed in the above-mentioned
.

150-3661
1C~83~94
formulations.
The exact compo~itlon of such formulations
is not crltlcal and may be varled to sult the intended
use.
The amount of photo-sensltizing agent employed
in the photo-polymerisable formulations of the invention
will vary depending on the proposed use. However, ln
general, ~atisfactory results may be obtained when
employed in an amount of from 0.01 to lO~, preferably
B 0~05 to 5~, of the weight of the~polymerisable system.
The inventlon 18 lllustrated by the following
Examples whereln parts and percentagesare by welght
and temperatures are ln Centlgrade.
-- 10 --

150-3661
1083294
EXAMPLE 1
A photo-polymerisable system consisting of
60 g of a prepolymer of the formula
CH2_CH-coo-CH2~CH(OH)~CH2~O ~ C(CH3) ~ O-CH2-CH(OH)
2 ~ C(CH3) ~ O-CH2-CH(OH)-CH2-OOC-CH-CH2
having a v18c08ity of about 9000 poise at 77C (cf.
U.S. Patent 3,713,864), and 35 g pentaerithrltol tetra-
acrylate and 5 g of a photo-sensitizer of the formula
~ O ~COCHC12
were applled with a spatula ln an amount of 3.5 g/m2
to matt art paper and cured in a U.V. Mini-Cure at
a belt speed of 71.6 m/mln. to give a non-stlcky,
shiny fllm.
In analogous manner, the photo-sensitizers
set out in the followlng Tables 1 and 2 are employed.
-- 11 --

150-3661
TAp,~01~3299~
Rl~ O ~ C - C (~) m ( C 1) 3-m
_ _ . . _ .. _
Ex . Rl R2 m
. ~ _. ¦ H ¦ 0
Sn-C4~19 - 1
~6 ~C1~3 ~ C113
oA Cl 2 5 i 2
~ 12 --

10832~4 150-3661
TABLE 1 (~ONTINUED)
. _
Ex . Rl R2 m
~o. O
¦ 13 -C- (H)m~Cl) 3-m
16 ~ -C- j
¦ 17 ~C- .¦ ¦ 1
1 8 ~ CH 3 ) 3C~ C -- ., l 1
. ~
-- 13 --

1~0-3661
1C)83Z94
TABLE 2
_
Ex, Ex. _
No . Formula No . Formula
__ O .... . _ .
2 2 <~ ~ C-CH Br2 3 ~C-C~2Cl
23 ~ o~c-c Br3 31~C-CHC12
O O
24 ~>~ C--CH2Cl 32~-C-CCl3
2 5 ~ C-CHC 12 3 3 (~ ~- C-CH2C 1
26 ~C-CCl3 34~ C-~C-CHC12
2 ? ~ S ~C--CH2C l O CH3 O
O 35Cl2HC-C~Cl ~ C CHC 2
28 ~ S~ C-CHCl2 O O
. O 36C12HC-C~so2~ C-C~IC12
29 ~ S~C-CHBr2 . O O
. 37ClH2C-C~S~ C-CH2Cl
. , . ,0, 0
38 C12HC-C~S~ C-CHCl2
. O O
39 Br2HC~C~ C-CH~r2
,
-- 14 --
. . ~

1~83294 50-3661
EXAMPLE 40
A photo-polymerisable system consisting of 50
parts of the acryl derivative of epoxylated linseed oil
(2.9 acryl groups per molecule on average), 20 parts
of neopentyl glycol diacrylate and 27 parts of phenoxy-
ethyl acrylate, and 5 parts of a photo-sensitizer of the
formula
~ ~ -C CC13 - ,
were applied onto matt art paper and cured in the
manner described in Example 1.
EXAMPLE 41
100 Parts of a photo-polymerisable system
consisting of 67 parts of polyester (produced from
maleic anhydride, phthalic anhydride and propane
1,2-diol) and 33 parts styrene, and 3 parts of a photo-
sensitizer of the formula
CH ~ O ~ C - CHC12
CH3
as well as 0.1 parts by weight of paraffin oil, were
applied and cured in accordance with the procedure of
Example 1.
- 15 -

~0~33Z9~
150-3661
The Example is repeated employing the photo-
sensitlzers of the formulae
O
(~_ O _~C _ CHBr2
and
O ~C--CBr3
EXAMPLE ~
A polymerisable polyester based acrylated
urethane system is produced by reactlng an hydroxy
functional saturated polyester (produced from adipic
acid, ethylene glycol and 1,6-hexane-dlol) with the
reactlon product of toluene di-160cyanate and
~-hydroxyethyl acrylate. 70 Parts of the resulting
system is employed in association with 30 parts of
pentaerythritol triacrylate and 3 parts of the photo-
sensitizer of the formula
~ O--~ C--CHC12
in analogous manner to that.described in Example 1.
The Example ls repeated employing an unsatu-
rated polyester produced from maleic acld anhydride,
diethylene glycol and i,3-butylene glycol.
In analogous manner to the procedures de-
scribed in Examples ~ to ~, the photo-sensitizers of
Examples 2 to ~ may be employed.
- 16 -
. : :
.

1083294 1 50-3661
The compounds employed in the preceding
Examples may be produced according to or in analogous
manner to the procedure described in Examples A and B
below.
EXAMPLE A
17.0 g of diphenyl ether and 11.3 g chloro-
acetyl chloride were dissolved in 200 ml of chlorobenzene.
To the solution so formed at room temperature and with
stirring were added 30 g of aluminium chloride over a
period of 2 hours. The reaction mixture was stirred for a
further 4 hours at 50. After cooling, 100 ml of concen-
trated HCl and 200 ml of ice water were added thereto.
The organic phase was separated off, washed with water,
and the solvent distilled off. After further washlng the
compound of Example 1 is obtained. M.P. 55-56.
EXAMPLE B
16.9 g of 4-trichloroacetyl-diphenyl ether
were dissolved at 78 in a mixture consisting of 70 ml
of acetic acid and 7 ml of water. To the solution so
formed, still at 78, were added successively 1.4 ml
concentrated H2SO4, 2.1 g HIO3 and 5.7 g iodine. The
reaction was allowed to proceed for 3 hours at 78 to
80. The light brown reaction mixture was added to
400 ml of water whereby a yellowish oil separated out.
- 17 -
'

1083Z94 150-3661
The separated oil was taken up in 100 ml of toluene
and separated from the aqueous phase. The toluene
phase was washed neutral, the solvent distllled off,
and the residue recrystallized from isopropanol. The
compound of Example ~ of Table 1 was obtained in
white crystalline form. M.P. 101-103.
In analogous manner the compound of Example~2
of Table 1 is obtained. M.P. 69-72.
-- 18 --