Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
2'097~38
PhotopolYmerizable Mixture and Recordinq
Material Pre~ared Therefrom
The invention relates to a photopolymerizable mixture
that comprises a polymeric binder, a polymerizable
compound, preferably an acrylic or alkylacrylic acid
ester, and also a photoinitiator combination.
Photopolymerizable mixtures of the aforementioned
general type are known.
Examples of such photopolymerizable mixtures are
described in EP-A 287 817, which comprise (meth)acrylic
acid esters having urethane groups, tertiary amino
i groups and, if desired, urea groups in the molecule,
polymeric binders and, as photoinitiators, a
combination of a photoreducible dye, a radiation-
sensitive trihalomethyl compound and an acridine,
phenazine or quinoxaline compound.
In EP-A 364 735 photopolymerizable mixtures are
described which contain the same or similar binders and
polymerizable compounds and also a photoinitiator com-
bination of a photoreducible dye, a radiolyzabletrihalomethyl compound, and a metallocene compound.
These mixtures have a particularly high light sensitiv-
ity, especially in the visible spectrum. This property
makes them particularly suitable for producing printing
plates on which images can be recorded with visible
laser light, for example with an argon ion laser. These
known mixtures generally comprise from 20 to 90 % by
weight, preferably from 40 to 80% by weight of binders.
However, there is an ever-increasing need to improve
the light sensitivity for the aforementioned use and
also for recording images by projection irradiation.
. .
- It is an object of the present invention to provide
photopolymerizable mixtures that are especially
suitable for producing printing plates having the high
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2~97~38
-- 2
degree of efficiency described in EP-A 364 735 and
whose light sensitivity in the near ultraviolet and in
particular in the visible spectral region is improved
still further compared to the mixtures described
therein.
According to the invention a photopolymerizable mixture
is proposed which comprises:
a) a polymeric binder,
b) a free-radically polymerizable compound having
at least one polymerizable group,
and, as photoinitiators:
c) a photoreducible dye,
d) a radiolyzable trihalomethyl compound, and
e) a metallocene compound,
wherein the binder (a) is present in an amount of from
about 5 to about 25~, the polymerizable compound (b) is
present in an amount of from about 60 to about 90%, and
the photoinitiators (c), (d) and (e) are present in a
total amount of from about 3 to about 20~, based on the
weight of the nonvolatile constituents.
The metallocenes that can be used as initiator
components are generally known as photoinitiators from
EP-A 364 735. In the present invention, preference is
given to metallocenes of elements of Group IV of the
Periodic System, in particular compounds of titanium
and zirconium. Of the numerous known metallocenes,
especially titanocenes, preference is given to
compounds of the formula I.
R1\ R3
/Me\ (I)
R2 R4
. .
2097~3~
In this formula:
Me is a tetravalent metal atom, preferably
Ti or zr,
R1 and RZ are identical or different cyclopenta-
dienyl radicals, which may be substitu-
ted, and
R3 and R4 are identical or different phenyl radi-
cals, which may also be substituted.
The cyclopentadienyl groups may be substituted by alkyl
radicals having 1 to 4 carbon atoms, chlorine atoms,
phenyl or cyclohexyl radicals, or may be coupled to one
another by alkylene groups.
R3 and R4 are preferably phenyl groups that contain at
least one fluorine atom in the ortho position relative
to the bond, and which may also be substituted by
halogen atoms such as F, Cl or Br, alkyl or alkoxy
groups having 1 to 4 carbon atoms, or a polyoxyalkylene
group, which may be etherified or esterified. The
polyoxyalkylene group may contain from 1 to 6 oxyalkylene
units and is preferably in the 4- position of the phenyl
radical, and may be etherified or esterified by an alkyl
or acyl radical having 1 to 18 carbon atoms; the
polyoxyalkylene group is preferably a polyoxyethylene
group. Particularly preferred are phenyl radicals
substituted by 4 or 5 fluorine atoms. The proportion by
weight of metallocene compound is normally from about
1.5 to about 10% by weight, preferably from about 2 to
about 6% by weight, based on the nonvolatile fractions
of the mixture.
The mixture according to the invention comprises, as
further photoinitiator constituent, a photoreducible
dye. Suitable dyes include, in particular, xanthene,
benzoxanthene, benzothioxanthene, thiazine, pyronine,
porphyrin or acridine dyes.
,~
2~971)~8
Suitable xanthene and thiazine dyes are described, for
example, in EP-A 287 817.
Suitable benzoxanthene and benzothioxanthene dyes are
described in EP-A 321 828.
A suitable porphyrin dye is, for example,
hematoporphyrin and a suitable acridine dye is, for
example, acriflavinium chloride hydrochloride. Examples
of xanthene dyes are Eosin B (C.I. No. 45 400), Eosin J
(C.I. No. 45 380), alcohol-soluble Eosin (C.I. No.
45 386), Cyanosin (C.I. No. 45 410), Bengal Rose,
Erythrosin (C.I. No. 45 430), 2,3,7-trihydroxy-9-
phenylxanthen-6-one, and Rhodamine 6 G (C.I. No.
45 160).
Examples of thiazine dyes are Thionin (C.I. No.
52 000), Azure A (C.I. No. 52 005) and Azure C (C.I.
No. 52 002).
Examples of pyronine dyes are Pyronine B (C.I. No.
45 010) and Pyronine GY (C.I. No. 45 005). The amount
of photoreducible dye is normally from about 1 to about
10% by weight, preferably from about 3 to about 8% by
weight, based on the nonvolatile fractions of the
mixture.
In order to improve the light sensitivity, the mixtures
according to the invention also comprise compounds
containing photolyzable trihalomethyl groups, which are
- generally known per se as free-radical-forming
photoinitiators for photopolymerizable mixtures. In the
present invention, as co-initiators of this type,
compounds containing chlorine and bromine, especially
chlorine, as halogens have proved particularly
suitable. The trihalomethyl groups may be bound ~-
directly or via a conjugated chain to an aromatic
~ carbocyclic or heterocyclic ring. Preference is given
; to compounds having a triazine ring in the parent
2~97038
-- 5
structure, which preferably carries two trihalomethyl
groups, in particular compounds such as are described
in EP-A 137 452, DE-A 27 18 259 and DE-A 22 43 621.
These compounds exhibit strong light absorption in the
near UV region, for example around 350-400 nm. Co-
initiators that do not themselves absorb, or only
slightly absorb, in the spectral range of the copying
light are also suitable, for example
trihalomethyltriazines, which contain substituents with
shorter electron systems capable of mesomerism or
aliphatic substituents. Also suitable are compounds
having a different basic skeleton, that absorb in the
shorter-wavelength UV range, for example phenyl
trihalomethyl sulfones, or phenyl trihalomethyl
ketones, for example phenyl tribromomethyl sulfone.
These halogen compounds are generally used in an amount
of from about 0.05 to about 4% by weight, preferably
from about 0.25 to about 1% by weight, based on the
nonvolatile constituents of the mixture.
The total amount of these three necessary initiator
components is from about 3 to about 20% by weight,
preferably from about 6 to about 12% by weight. The
proportion of titanocene compound is preferably from
about 30 to about 55% by weight, that of trihalomethyl
compound is from about 3 to about 15% by weight, and
that of photoreducible dye is from about 40 to about
67% by weight, based on the total amount of
photoinitiators (c), (d) and (e).
The mixtures according to the invention may contain an
acridine, phenazine or quinoxaline compound as further
initiator constituent. These compounds are generally
known as photoinitiators and are described in
DE-C 20 27 467 and 20 39 861. The sensitivity of the
mixture, particularly in the near ultraviolet region,
is increased by means of these compounds. Suitable
examples of this class of compound are described in the
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2097038
-- 6 --
aforementioned patents. The amount of this component in
the mixture of the present invention is in the range
from 0 to about 5% by weight, preferably from about
0.05 to about 3% by weight.
When a further increase in sensitivity of the mixture
in the visible spectrum is necessary, this is achieved
by adding a compound of the dibenzalacetone or coumarin
type. This addition produces a higher resolution of the
copy and a continuous sensitization of the mixture for
the visible spectrum up to wavelengths of about 600 nm.
Suitable examples of these compounds are
4,4'-disubstituted dibenzalacetones, for example
4-diethylamino-4'-methoxydibenzalacetone, or coumarin
derivatives such as 3-acetyl-7-diethylaminocoumarin,
3-benzimidazolyl-7-diethylaminocoumarin or carbonyl-
bis(7-diethylaminocoumarin). The amount of this
compound is in the range from 0 to about 5% by weight,
preferably from about 0.05 to about 2% by weight, based
on the nonvolatile constituents of the mixture.
Suitable polymerizable compounds for the purposes of
the invention are described, for example, in US
i Patents 2,760,863 and 3,060,023.
.
~` Preferred examples are acrylic and methacrylic esters
of dihydric or higher alcohols, for example ethylene
glycol diacrylate, polyethylene glycol dimethacrylate,
acrylates and methacrylates of trimethylolethane,
trimethylolpropane, pentaerythritol and
dipentaerythritol, and of polyhydric alicyclic alcohols
or N-substituted acrylic and methacrylic acid amides.
Also, the reaction products of monoisocyanates or
diiosocyanates with partial esters of polyhydric
alcohols are advantageously used. Such monomers are
described in DE-A 20 64 079, 23 61 041 and 28 22 190.
Particularly preferred are polymerizable compounds that
contain at least one photooxidizable group and, if
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2~97038
-- 7
deslred, at least one urethane group in the molecule.
Suitable photooxidizable groups are in particular amino
groups, urea groups, thio groups, which may also be
constituents of heterocyclic rings, and enol groups.
Examples of such groups are triethanolamino,
triphenylamino, thiourea, imidazole, oxazole, thiazole,
acetylacetonyl, N-phenylglycine and ascorbic acid
groups. Preference is given to polymerizable compounds
containing primary, secondary and, preferably, tertiary
amino groups.
Examples of compounds containing photooxidizable groups
are described in EP-A 287 818, 355 387 and 364 735. Of
the compounds described there, preference is given to
those that also contain, in addition to a tertiary
amino group, a urea group and/or a urethane group.
Groups of the formula
/N-CC~-N\
in which the valences on the nitrogen are saturated by
unsubstituted or substituted hydrocarbon radicals,
should be regarded as urea groups.
The proportion by weight of polymerizable compounds in
the photopolymerizable layer is normally from about 60
to about 90% by weight, preferably from about 70 to
about 85% by weight, based on the nonvolatile
constituents.
Examples of binders that can be used include
poly(meth)acrylic acid alkyl esters, in which the alkyl
group is for example, methyl, ethyl, n-butyl, i-butyl,
n-hexyl or 2-ethylhexyl, copolymers of the
aforementioned (meth)acrylic acid alkyl esters with at
least one monomer, such as acrylonitrile, vinyl
chloride, vinylidene chloride, styrene or butadiene;
polyvinyl acetate, vinyl acetate copolymers,
,
2097038
-- 8
polyurethanes, methyl cellulose, ethyl cellulose,
polyvinyl formal and polyvinyl butyral.
Particularly suitable are binders that are insoluble in
water, but are soluble in organic solvents and are
soluble, or at least swellable, in aqueous-alkaline
solutions.
In particular there should be mentioned carboxyl group-
containing binders, for example copolymers of (meth)-
acrylic acid and/or their unsaturated homologs, for
example crotonic acid, copolymers of maleic anhydride
or its monoesters, reaction products of hydroxyl group-
containing polymers with dicarboxylic anhydrides, or
their mixtures.
The afore-described polymers are particularly suitable
if they have a molecular weight from about 500 to about
200,000 or above, preferably from about 1000 to about
100,000, and either have acid numbers from about 10 to
about 250, preferably from about 20 to about 200, or
hydroxyl numbers from about 50 to about 750, preferably
from about 100 to about 500.
Preferred alkali-soluble binders include:
copolymers of (meth)acrylic acid with alkyl (meth)acry-
lates, (meth)acrylonitrile or the like, vinyl acetate
copolymers, copolymers of crotonic acid with vinyl
25 acetate, alkyl (meth)acrylates (meth)acrylonitrile or
the like, copolymers of vinylacetic acid, with alkyl
(meth)acrylates, copolymers of maleic anhydride with
unsubstituted or substituted styrenes, unsaturated
hydrocarbons, unsaturated ethers or esters, esterifica-
tion products of copolymers of maleic anhydride,
esterification products of hydroxyl group-containing
polymers with anhydrides of dicarboxylic or higher
polycarboxylic acids, for example copolymers of
hydroxyalkyl (meth)acrylates with alkyl
(meth)acrylates, (meth)acrylonitrile or the like, ~-
2097~38
g
copolymers of polyurethanes, provided they contain a
sufficient number of free OH-groups, of epoxy resins,
polyesters, partially saponified vinyl acetate copoly-
mers, polyvinyl acetals having free OH-groups,
copolymers of hydroxystyrenes with alkyl
(meth)acrylates or the like, and also phenol-
formaldehyde resins, for example Novolaks.
The amount of the binder in the light-sensitive layer
is normally from about 5 to about 25% by weight,
preferably from about 10 to about 19~ by weight.
Depending on the intended use and desired properties,
the photopolymerizable layers may comprise various
substances as additives. Examples of such additives
include inhibitors to prevent thermal polymerization of
the monomers, hydrogen donors, dyes, colored and non-
colored pigments, color formers, indicators,
plasticizers and chain transfer agents. These constitu-
ents should be conveniently selected so that they
absorb as little as possible in the actinic radiation
range important for the initiation process.
Actinic radiation is understood in the context of this
description to be any radiation whose energy
corresponds at least to that of visible light.
Particularly suitable are visible light and long-wave
UV radiation, though short-wave UV radiation and laser
radiation are also suitable. The light sensitivity
extends from about 300 nm to 700 nm and thus covers an
extremely broad range.
The combination of photoreducible dyes with
photolyzable halogen compounds and metallocenes
produces a synergistic initiator system that is very
active especially in the long-wave spectral region at
or above 455 nm. Particularly high light sensitivities
are obtained in combination with polymerizable
; 35 compounds that contain photooxidizable groups. Compared
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2097~38
-- 10 --
with the known mixtures of the foregoing composition,
the mixtures according to the invention, which contain
substantially smaller amounts of binders and different
amounts of initiators, have a further improved light
sensitivity.
The following may be mentioned as possible uses of the
material according to the invention: recording layers
for the photomechanical production of printing plates
for relief printing, planographic printing, gravure
printing and screen printing, of relief copies, for
example production of braille text, of individual
copies, tanned images, pigmented images, etc. The
mixtures may also be used for the photomechanical
production of etch resists, for example for producing
name plates, of printed circuits, and for chemical
milling. The mixtures according to the invention are
especially important as recording layers for producing
planographic printing plates and for use in photoresist
technology.
Suitable layer carriers for the recording material
according to the invention are for example aluminum,
steel, zinc, copper and plastics films, for example of
polyethylene terephthalate or cellulose acetate, and
also screen printing carriers such as Perlon gauze. It
is convenient in many cases to pretreat (chemically or
mechanically) the carrier surface, the purpose of which
pretreatment is correctly to adjust the adhesion of the
layer, improve the lithographic properties of the
carrier surface, or reduce the reflectance of the
carrier in the actinic region of the copying layer ~-
(antihalation).
The light-sensitive materials are prepared in a known
manner. For example, the layer constituents can be
taken up in a solvent and the solution or dispersion
can be applied to the intended carrier by pouring,
209703~
-- 11 --
spraying, dipping, roller application, etc., and then
dried.
Due to the broad spectral sensitivity of the recording
material according to the invention, all light sources
known to those skilled in the art may be used, for
example tubular lamps, pulsed xenon lamps, metal
halide-doped high-pressure mercury vapor lamps and
carbon arc lamps. Furthermore, irradiation in normal
projection and magnification equipment under the light
from metal filament lamps and contact irradiation with
normal incandescent lamp bulbs is possible with the
light-sensitive mixtures according to the invention.
Irradiation can also be effected with the coherent
light from a laser. Tuned lasers are suitable for the
lS purposes of the present invention, for example argon
ion, krypton ion, dye, helium-cadmium and helium-neon
lasers, which emit in particular from about 250 to
about 650 nm. The laser beam can be controlled by
means of a preprogrammed linear and/or dot-like
movement.
In general it is convenient to exclude as far as
possible the influence of atmospheric oxygen on the
mixtures during the light polymerization. In the case
where the mixture is used in the form of thin copying
layers it is recommended to apply a suitable cover film
that is only slightly permeable to oxygen. This cover
film may be self-supporting and can be removed before
the copying layer is developed. Polyester films for
example are suitable for this purpose. The cover film
may also comprise a material that dissolves in the
developer liquid or that can at least be removed during
development from the non-hardened places. Suitable
materials for this purpose include polyvinyl alcohol,
polyphosphates, sugars, etc. Such cover layers
generally have a thickness of from about 0.1 to about
10 ~m, preferably from about 1 to about 5 ~m.
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20970t',8
- 12 -
The materials are processed further in a known manner.
A post-heating may be carried out after irradiation in
order to improve the crosslinking of the layer. The
materials are developed with a suitable developer solu-
tion, for example with organic solvents, but preferablywith a weakly alkaline aqueous solution, the non-
irradiated parts of the layer being removed and the
irradiated regions of the copying layer remaining on
the carrier. The developer solutions may contain a
small proportion, preferably less than 5% by weight, of
water-miscible organic solvents. They may also contain
wetting agents, dyes, salts and other additives.
The whole cover layer together with the non-irradiated
regions of the photopolymerizable layer are removed in
the development process.
Embodiments of the invention are given hereinafter. In
these embodiments parts by weight (pbw) and parts by
volume (pbv) are in the same ratio as g to ccm. Unless
otherwise stated, percentages and amounts are by
weight.
Examples 1-7(Comparative examples)
~ .
Solutions of:
2.87 pbw of a polymeric binder
6.76 " of the reaction product of 1 mol of
triethanolamine with 3 mol of isocyanato
ethyl methacrylate, as monomer,
0.18 " alcohol-soluble Eosin (C.I. 45 386)
0.14 " 2,4-bis-trichloromethyl-6-(4-styrylphenyl)-s-
triazine, and
0.05 " dicyclopentadienyl bis(pentafluorophenyl-
titanium) in
85 " propylene glycol monomethyl ether and
46 " butanone
'
~, ~ . . . ... . .
2097038
- 13 -
were applied to electrolytically roughened and
anodically oxidized aluminum plates having an oxide
layer of 3 g/m2 that had been pretreated beforehand with
an aqueous solution of polyvinylphosphonic acid. The
layers were dried for 2 minutes at 100C in a
circulating air cabinet and then had a layer weight of
2.1 g/m2. An 8% strength aqueous solution of polyvinyl
alcohol (12~ residual acetyl groups, K value 4) was
then applied in such a thickness that a layer weight of
2.4 g/m2 was obtained after the drying (2 minutes at
100 C) .
~he printing plates obtained were in each case irradi-
ated for 20 seconds with a 60 W incandescent lamp at a
distance of 80 cm under a 13-step standard stepped
photometric absorption wedge with density steps of
0.15. After irradiation the plates were post-heated for
one minute at 100C and then developed with a developer
having the following composition:
1 pbw trisodium citrate x 2 H2O,
2 " 1-amino-2-propanol,
1.4 " benzyl alcohol,
l.S " sodium cumol sulfonate (40% strength
solution)
0.04 " sodium metasilicate x 5 H2O5 0.02 " fatty alcohol polyglycol ether (non-ionogenic
wetting agent)
94.04 " water
In a further experiment the light-sensitive plates were
treated with the developer without any image-forming
irradiation. The following binders were used:
Example 1 terpolymer of styrene, n-hexyl methacrylate
and methacrylic acid (10:60:30; acid number
190)
20~7~38
- 14 -
Example 2 copolymer of styrene and maleic acid semi-
ester (acid number 185; ~Scripset 540)
Example 3 copolymer of 95% vinyl acetate and 5%
crotonic acid
Example 4 copolymer of 65% vinyl acetate and 35%
dibutyl maleate
Example 5 copolymer of acrylic acid, styrene and
a-methyl styrene, acid number 245; M~ 7000
Example 6 reaction product of a polyvinyl butyral (71%
vinylbutyral units, 2% vinyl acetate units,
27% vinyl alcohol units, M~ = 70000-80000)
with maleic anhydride; acid number 30
Example 7 methylmethacrylate/methacrylic acid
copolymer, acid number 117
The results are summarized in Table 1. The second
column gives the number of the solid, i.e. completely
. hardened wedge steps. The comparisons show, with the
specified binder content, none of the layers could be
satisfactorily developed in such a way that the
irradiated regions of the layer remained unaffected
while the non-irradiated regions were completely
removed.
.
2097038
- 15 -
Table 1
With irradiation Without
irradiation
Wedge Remarks
steps
1 4 _ partially
delayered
2 _ not partially
developed delayered
3 1 _ completely
delayered
4 _ completely completely
delayered delayered
_ not partially
developed delayered
I
6 _ not not delayered
developed
7 _ not partially
developed delayered
Exam~les 8-10 (Com~arative Examples)
Printing plates were produced as described in Example
l, the monomer being replaced by the same amount of
monomers specified in Table 2. The further procedure
was as described in Example 1; Table 2 shows the number
of solid wedge steps.
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20970~8
- 16 -
Table 2
Example Monomer Wedge steps ¦
I
1 as specified there
8 the reaction product of 2 mol 4
of isocyanato ethyl
methacrylate and 1 mol of 2-
hydroxyethylpiperidine
9 reaction product of 3 mol of 3
isocyanato ethyl methacrylate
and 1 mol of diethanolamine
reaction product of 2 mol of 4
hexamethylene diisocyanate,
2 mol of hydroxyethyl meth-
acrylate and 1 mol of 2-hyd-
roxyethylpiperidine
Example 11 (Comparative ExamPle)
A printing plate was produced as described in Example
1. The following coating solution was used.
2.87 pbw of the terpolymer of Example 1
6.64 " of the reaction product of 2 mol of
hexamethylenediisocyanate, 2 mol of
2-hydroxyethyl methacrylate and 1 mol of
2-(2-hydroxyethyl)piperidine, as monomer
0.18 " alcohol-soluble Eosin (C.I. 45386)
0.14 " of the triazine given in Example 1
0.05 " of the titanocene given in Example 1,
and
0.12 " Renol blue (C.I. 20 505) in
" propylene glycol monomethyl ether and
46 " butanone.
After irradiation and development as described in
Example 1, 4-5 solid wedge steps were obtained.
- 17 - 2097038
Example 12 (Comparative Example)
The same procedure as in Example 11 was adopted, though
the compound specified in Example 1 was used, in the
same amount as in Example 11, as monomer. Four solid
wedge steps were obtained.
Example 13 (Comparative Example)
The same procedure as in Example 11 was adopted, though
the reaction product of 2 mol of isocyanato ethyl meth-
acrylate and 1 mol of 2-(2-hydroxyethyl)piperidine was
used, in the same amount as in Example 11, as monomer.
Four solid wedge steps were obtained.
Example 14 (Comparative ExamPle)
The same procedure as in Example 11 was adopted, though
the reaction product of 3 mol of isocyanato ethyl
methacrylate and 1 mol of diethanolamine was used, in
the same amount as in Example 11, as monomer. Three
solid wedge steps were obtained.
Example 15 (Comparative Exam~le~
Printing plates were produced as described in Example
11! the amounts of the constituents being altered in
each case as follows:
a) 6.36 pbw monomer (- 0.28)
0.46 " Eosin (+ 0.28)
b) 6.74 pbw monomer (+ 0.1)
0.04 " triazine (- 0.1)
c) 6.4 pbw monomer (- 0.24)
0.29 " titanocene (+ 0.24)
;
d) 3 03 pbw terpolymer (+ 0.16)
6.48 " monomer (- 0.16)
e) changes (a) and (d)
f) changes (a), (b) and (d)
g) changes (a), (b), (c) and (d)
,
.,
.,
~0370c,~
- 18 -
The multiple changes (e), (f) and (g) were made so that
the total amount remained constant in each case. The
plates were otherwise produced and processed as in
Example 11. The following numbers of completely solid
wedge steps were obtained:
Example Wedqe steps
15 a 4-5
15 b 4
15 c 6-7
15 d 4
15 e 4
15 f 4
15 g 7-8
Exam~les 16-22 (Comparative Examples)
Printing plates were coated as described in Example 1
with the following solution:
3.04 pbw binder
6.06 " of the monomer given in Example 11,
0.46 " alcohol-soluble Eosin
0.04 " of the triazine given in Example 1,
0.29 " of the titanocene given in Example 1, and
0.12 " Renol blue in
: 85 " propylene glycol monomethyl ether and
46 " butanone
The plates were produced and processed as described in
Example 1. The following table shows the numbers of
solid wedge steps obtained with irradiation times of 20
and Z seconds under the conditions specified in
Example 1.
,. ~ . ,.. ., , . -, . : -
2097~38
-- 19 --
Example BinderWedge steps
according to
16 Example~0 C~-3
~ 1 ~
7_8
Examples 23-31 (including Comparative
Examples 24, 25, 27, 28, 30 and 31)
Coating solutions according to the formulation given in
Example 16 were used to prepare printing plates, the
nature and amount of the binder and also the amount of
the monomer being specified in the following table. The
table also shows the number of solid wedge steps after
6 seconds' irrsdiation.
(j ~ '
.,
- 20 - 2 0 9 7 0 3 ~
Example Binder Amount Amount of Wedge
according pbw monomer, steps
to Example pbw
23 7 1.5 7.6 5-6
24 7 3.0 6.1 4
7 4.5 4.6
26 1 1.5 7.6 5-6
27 1 3.0 6.1 3
28 4.5 4.6
29 1.5 7.6 5-6
2 3.0 6.1 3
31 2 4.5 4.6 _
