Note: Descriptions are shown in the official language in which they were submitted.
Hoe 77~K 017 (K 2543)
The present invention relates to radiation sensitive composi-
tions, in particular copying compositions, which contain light- -
sensitive organo-halogen compounds whose decompos1t1on under the
influence of actinic radiation causes chemical or physical changes
in the composition or in one or more of its components.
Radiation sensitive organo halogen compounds are used in
industry, on the one hand, for the purpose of utilizing the free radi-
cals formed under the influence of radiation for initiating polymeriza-
tion reactions or color changes, and, on the other hand, for effecting
secondary reactions caused by the liberated acid.
Hitherto known organo halogen compounds belong to a wide
variety of chemical compounds.
Despite wide differences in their structure, the hltherto known
organo-halogen compounds do not meet the requirements ~or optlmum
sensitivity within~ ~he main emission range of the light sources pres~
entlv used in the art, i.e. the known compounds have their W
; absorption maxima at relatively low wavelength ranges~
Although some undesirable characteristics are elminated by
the chromophore-substituted vinyl halogen methyl-s-triazines dis-
closed in German Offenlegungsschriften Nos . 2 ,243 ,621 and
2,306,248, they have the disadvantage that their preparation is rela-
tively complicated. Thus, 2-methyl-4,6-bis-trichloromethyl-s-
triazine, for example, must be first obtained by co-trimerization of
acetonitrile and trichloro acetonitrile, and this compound, which is
extremely reactive towards nucleophilic compounds, must then be
~- condensed, under the condltions of a Knoevenagel reaction, with
aldehydes, sorne of which have a complicated stmcture and thus are
expensive to prepare. The resulting vinylene yroup links the triazine
- . . ~,.~
5~8 ~ ~:
group to a chromophore and forms part of the entire chromophoric system
which is responsible for the absorption within the visible and long-wave
ultraviolet range of the spectrum which is desired.
It is a purpose of the present invention to provide easily obtain-
able organo-halogen compounds which are sensitive to actinic radiation and
have a good sensitivity in the ultraviolet and short-wave visible range of
the spectrum and thus are suitable Eor use in radiation sensitive compositions.
The present invention relates to a radiation sensitive composition
which comprises an ethylenically unsaturated compound capable oE undergoing
a polymerization reaction-initiated by free radicals or whose solubility is
changedby the action of an acid and which contains, as the radiation-
sensitive compound, an s-triazine corresponding to Formula I:
N-~ / n 3 n
R ~ I
,
wherein
X is bromine or chlorine, and
- m and n are whole numbers ranging from 0 to 3 which, taken
toge-ther, do not exceed 5.
In the composition according to the învention, in this compound,
R is a substituted or unsubstituted, bi-or tri-nuclear
;; 20 aromatic or heterocyclic aromatic group which may be
partially hydrogenated and which is linked via an
;~ unsaturated nuclear carbon atom.
Preferably, the group R is linked via an aromatic carbon atom.
: ..
` ':-
i~
Hoe 77/K 017 (K 2543)
In connection with this application, the term "actinic radiation"
means any radiation whose energy at least corresponds to that of
shor~-wave visible light. Long-wave ultraviolet radiation is particu-
larly suitable, but electron and laser beams also may be used.
The symbols in the above Formula I preferably have the follow-
ing meanings:
R is a bi- or trinuclear condensed aryl
group or a corresponding heterocyclic aro-
matic group with O, S, or N as heteroatoms
and may be partially hydrogenated. Alter-
natively, R may be a diphenyl group . The
nuclei of the group R may carry one or more
substituents.
X preferably is chlorine, and
n and m preferably are zero.
Examples of suitable bi- and trinuclear aromatic groups are:
Naphthalene, anthracene, phenanthrene, quinoline, iso-
quinoline, benzofuran, benzopyran, dibenzofuran, benzothiophene,
dibenzothiophene, acenaphthene, benzoxa~ole, fluorene, tetrahydro-
phenanthrene, and dihydrophenalene. Naphthalene is particularly
advantageous .
Sultable substituents are, for example:
Halogen, especially chlorine and bromine; lower alkyl groups,
~; preferably -with 1 to 3 carbon atoms which may be substituted; substi-
tuted or unsubstituted aryl groups; nitro groups; sulfonyl groups; alkyl
mercapto groups; phenyl mercapto groups; acyl groups; aryloxy groups;
hydroxy groups and, preferably, alkoxy groups. Alkoxy groups with 1
to 8 carbon atoms which, in turn, may be substituted by halogen,
,
-- 3 --
:JL~ 5~ Hoe 77/K 017 (K 2543)
phenyl or phenoxy and in which one or more methylene groups may be
replaced by O- or S-brldges, and phenoxy, cycloalkoxy, and alkenyl~
oxy ~roups are particularly advantageous.
Particularly preferred are s-triazines corresponding to Formula
I in which R is a grQup corresponding to Formula II:
2 ll
wherein
Rl is H or -OR3, but preferably -OR3,
R2 is H, Cl, Br, or a lower alkyl, alkenyl,
aryl, or a substituted or unsubstituted
alkoxy group wl-th 1 to 4 carbon atoms,
: preferably H, alkyl with 1 to 3 carbon
atoms, or alkoxy with 1 to 3 carbon atoms, .
and
R3 is an alkyl group with 1 to 8 carbon atoms
which may be substituted by halogen, prefer-
ably chlorine or bromine, or by aryl or
aryloxy groups, and in which one or more
methylene groups may be replaced by O- or
S-bridges, or R3 is a cycloalkyl, alkenyl, ~`
. or aryl group, especially an alkyl or alkoxy-
alkyl group with 1 to 4 carbon atoms,
or
R1 and R2 taken together, form an alkylene group which
. preferably is l1nked to the naphthalene nuc-
leus in such a manner that a 5- or 6-membered
~; ring results,
- 4 -
3~3 Hoe 77/K 017 (K 2543)
X is a Cl atom, and
n = m= zero.
Compounds in which the s-triazine group and an alkoxy group
are arranged in the 1,4 position or the 2,6 position of the naphthalene
nucleus oi Formula II are of particular advantage.
Because the photochemical activity of the initiators is only
insignificantly iniluenced by the number of carbon atoms in the alkoxy
groups, the limitation to 8 carbon atoms in the -OR3 group is not to be
regarded as a rigid limit, but may be exceeded, for example by
nonyloxy, dodecyloxy, or octadecyl groups.
The following organo halogen compounds are particularly ad-
vantageous compounds:
2 - (naphth- 1 -yl ) - 4, 6 -bi s - trichloromethyl - s -tria zin e,
2-(4-methoxy-naphth-1-yl)-4,6-bis-trichloromethyl-s-triazine,
2-(4-ethoxy-naphth-1-yl)-4,6-bls-trichloromethyl-s-triazine,
2-t4-butoxy-naph~h-1-ylj-4,6-bis-trlchloromethyl-s-triazine, '
2-C4-(2-methoxyethyl)-naphth-1-y~l-4 ,6-bis-trichloromethyl-s-triazine,
2- C4-(2-ethoxyethyl)-naphth-1 -yL~-4, 6-bis-trichloromethyl-s-triazine,
2- [4- (2-butoxyethyl)-naphth-1-y~-4, 6-bis-trichloromethyl-s-triazine,
2-(2-methoxy-naphth-1-yl)-4, 6-bis-trichloromethyl-s-triazine,
2- (6-methoxy-5-methyl-naphth~2-yl)-4, 6-bis-trichloromethyl-s-
triazine,
; 2-(6-methoxy-naphth-2-yl)-4,6-bis-trichloromethyl-s-triazine,
:: `
2 - (5 - methoxy-naphth- 1 -yl ~ -4, 6 -bi s -trichloromethyl - s -triaz ine,
2- (4, 7-dimethoxy-naphth-1 -yl)-4, 6-bls-trichloromethyl-s-triazine,
2-(6-ethoxy-naphth-2-yl)-4, 6-bis-trichloromethyl-s-triazine,
2- (4, 5-dimethoxy-naphth-1-yl)-4, 6-bis-trichloromethyl-s-triazine,
:
2-(acenaphth-5-yl)-9, 6-bis-trichloromethyl-s-triazine, and,
slightly less active,
'
-- 5 --
Hoe 77/K 017 (K 25~3)
2 -(naphth-2-yl)-4, 6-bis-trichloromethyl-s-triazine .
The following are suitable halogen compounds selected from
groups which do not come under Formula II:
2-(phenanthr-9-yl)-, 2-(dibenzothiene-2~yl)-, 2~(benzo-
pyran-3-yl)-s-triazine, and the 2-(4-alkoxyanthra~1 yl)-4,6-bis-
trichloromethyl-s-triazines. The absorption of the last mentioned
class of compounds extends beyond 500 nm.
The aryl-halogen-methyl-trlazines according to the present
invention are prepared, in the simplest manner, by cotrimerization of
the aryl carboxylic acid nitriles with halogen aceto nitriles, in the
presence of hydrochloric acid and Friedel-Crafts catalysts, e.g.
AICl3, AlBr3, TiC14, or borotrifluoride etherate, analogously to the
method described in "Bull. Chem. Soc. Jap.", 42, 2924, (1969). Other
ways of synthesizing the compounds are by reacting aryl amidines with
polychloroaza-alkenes, according to the method published in "Angew.
Chem." 78, 982 tl966), or by reacting carboxylic acid chlorides or
-anhydrides with n-(iminoacyl)-trlchloro acetamidines; 2-aryl-4-
methyl-6-trichloromethyl-s-triazines alao may be easily prepared by
the last-mentioned reaction, as is disclosed in British Patent No.
2~ 912,112 Methods for the subsequent chlorination and bromination of
alkyl substituents in s-triazines, to form halogen alkyl-s-triazines, ~ ; ~
and exchange reactions by which bromine atoms in tribromomethyl
groups may be replaced by hydrogen and trlhalogen methyl groups in ~ ;~
s-triazines may be replaced by amino or alkoxy groups are published
in "J. Org. Chem.", 29, 1527 ~1964). 50me of the nitrites used for
co-trimerization are commercially available or may be prepared in a
.
simple manner, for example by dehydration of carboxyl1c acid amides
or oximes or by reaction of aromatic hromine compounds with copper-
I~cyanide .
Hoe 77/K 017 (K 2534)
Frequen~ly, it is of advantage to react carboxylic acids or
activated aromatic compounds first with chlorosulfonyl lsocyanates
(CSI) and then w1th dimethyl formamide, in one operation, thus forming
the nitriles, after the intermediate formation of carboxylic acid amide-
N-sulfochlorides, as described in "Chem. Ber.", 100, 2719 (1967).
Besides the nitriles, from which the bis~trichloromethyl-s-
triazines mentioned in the Examples are derived, the following com-
pounds are also suitable as educts, for example:
4-chloro-1-, 5-chloro-1-, 4-bromo-1-, 5-bromo-1-, 2, 6-
dimethoxy-1-, 2, 7-dimethoxy-1-, 5-nitro-1-, 3, 6-dichloro-1-,
1-chloro-2-, 5-chloro-2-, 6-bromo-2-, 4-methyl-1-, 5-methyl-1-,
2-ethyl-1-, 3,4-dimethyl-1-l 3,6-dimethyl-2-, 4-isopropyloxy-1-,
4-bromo-3-methoxy-2-, 4-(2-chloropropyl)-1-, 4-allyloxy-1-, 4-
cyclohexyloxy-1-, 4-n-octyloxy-1 , 4-phenoxy-1-, 4-p-tolyloxy-1-,
4-benzyloxy-1-, 4-(2-ethylmercaptoethyl)-1-, and 4-phenyl-1--
naphthonitrile, and also 4-acetyl-1-, 4-acetoxy-1-, 4-hydroxy-1-,
and 4-methylmercapto-1-naphthonitrile; 2-chloro-, 4'-nitro-, 4i-
bromo-, 3-bromo-diphenyl-4-carbonitrile, benzothiophene-2-carbo-
nitrlie, -5-carbonitrile, and-7-carbonitrile, dibenzothiophene-4-
carbonitrile, benzofuran-2- and -3-carbonitrile, dibenzofuran-1-
~' carbonitrile, -2-carbonitrile, and-3-carbonitrile, anthracene-1-
- carbonitrile and -2-carbonitrile, 4-methyl-anthracene-1-carbonitrile,
3-chloro-anthracene-1-carbonitrile, phenanthreno-1-carbonltrile and
-2-carbonitrile, and 3-chloro-phenanthreno-9-carbonitrile, acridine-
-2-carbonitr~le, fluorene-2-carbonitrile, and-4-carbonitrile,
quinoline-4-carbonitrile, isoquinoline 5-carbonitrile, benzoxazole-
2-carboni~rile, xanthene-4-carbonitrile, acenaphthene-5-carboni-
- trile, 2,3-dihydrophenalene-6-carbonitrile, and 1,2,3,4-tetrahydro-
phenanthreno-9 -carbonitrile .
Hoe 77/K 017 (K 2543)
With the exception of the unsubstituted 2-naphth-1-yl- and 2-
naphth-2-yl-4,6-bis~trichloromethyl-s-triazines, which also are not
known as photoinitiators, the aryl-halogen-methyl-s-triazines accord-
ing to the present invention have not yet been disclosed in the
literature .
The new photoinitiators have a wide range of applica~ions.
For example, they may be used as highly effective initiators for
photopolymerization reactions triggered by free radicals. Suitable
monomers undergoing such polyaddition reactions are, for example:
mono- bis-, tris-, and tetraacrylates and -methacrylates of
mono- and poly-functional alcohols or phenols, acrylic and metha-
crylic acid arnides derived from mono or poly-functional amines,
further vinyl esters and vinyl amides. Polymerizable compositions
of this type may further contain fillers, binders, polymerization in-
hibitors, dyestuffs, color couplers, plastici~ers, adhesion promoters
or oxygen absorbing agents, in varying quantities. If the composi-
tions are applied in the form of layers to supports, which may be
chemicaLly pretreated, if desired, for example to steel, chromium,
copper or brass foils, or to plastic materials, paper, glass, wood, or
ceramics, or to a composite material comprising two or more of these
materials, the light-sensitive layer also may be covered by a protec-
tive coating which inhibits the access of oxygen.
The photoinitiators according to the invention are effective in
;` quantities as low as 0.05 per cent of the solids content of the compo-
sition, and an increase of this quantity beyond 10 per cent is not
advisable, as a rule. Preferably, concentrations between 0.4 and 7
per cent by weight are used.
:'
. .
;3~ Hoe 77/K 017 (K 2543)
Furthermore, the photoinitiators according to the invention may
be used in those radiation-sensitive compositions which undergo a
change in their properties by the action of acid catalysts formed dur-
ing photolysis oi the initiator. In this connection, the cationic
polymerization of systems contalning vinyl ethers, N-vinyl compounds,
such as N-vinyl-carbazole, or special acid-variable lactones is to be
mentioned, without precluding, however, that in some of these sys-
tems radical-initiated reactions also may take place. Furthermore,
amino plastics, such as urea/formaldehyde resins, melamine/
formaldeh~de resins, and other N-methylol compounds, and phenol~
formaldehyde resins are composltions which are hardened by acids.
Although it is normal for epoxy resins to be hardened by Lewis acids
or by those acids whose anions are less nucleophilic than chloride or
bromlde, i.e. the anions of the hydrohalic acids formed during photoly-
sis of the new photoinitiators, layers composed of epoxy resins and
novolaks harden readily in the presence of the aryl-halogen-methyl-
s-triazines accordin~ to the invention.
As another advantageous property of the new photoinitiators
according to the invention, they are capable of causing color changes
in colored systems during photolysls, or of initiating color formation
in color couplers, e.g. leuco compounds, or of causing bathochromic
color displacement or deepening in mixtures containing cyanine,
merocyanine, or styryl color bases. Further, in mixtures such as
;- those disclosed in (~;erman Offenlegungsschrift No. 1,572 ,080, which
contain a color base, N-vinyl carbazole, and a halogenated hydrocar-
bon, the halogen compound tetrabromomethane may be replaced by a
- small percentage, i.e. about 1/40, of its quantity of aryl-bis-
trichloromethyl-s-triazine .
:
::. _ g _
~35~ Hoe 77/K 017 (K 2543)
Color changes are very desirable for certain technlques, for
example in the manufacture of printing plates, because they render it
possible to examine the exposed plate even before it is developed.
The acid donors disclosed in German Offenlegungsschriften Nos~
2,331,377, and 2,641,100, advantageously may be replaced by the
photoinitiators according to the present invention.
Among the compositions according to the invention, those are
particularly advantageous, however,which in addition to the aryl halo-
gen methyl-s triazines, contain, as an essential component, a com-
pound containing at least one C-O-C bond capable of being split up
by an acid.
The following substances are mentioned as examples of com-
pounds which can be split up by acids:
A. Compounds containing at least one ortho-carboxylic acid
ester- and~or carboxylic acid amide-acetal grouping; the
compounds m-y have a polymeric character and the group-
ings may be present as connecting elements Ln the main
chaln or as lateral substituents. ;~
~ .
B. Polymeric compounds containing recurrent acetal and/or
ketat grouplngs in whlch both carbon atoms in the a-position
of the alcohols required for forming the groupings are
alipha tic .
Compounds of type A which may be split up by acids are de-
scribed in detail as components of radiation sensi~ive copying compo-
sitions in German Offenlegungsschrift No. 2,610,842; copying com-
positions containing compounds of type B are the object of copending
application Serial No. ~0~ , filed ~7f~,~' Z/~
simultaneously with the present application.
-- 10 --
~1~3~i~8 Hoe 77/K 017 (K 2543)
Further compounds capable of being split up by aclds are, for
example, the particular aryl--alkyl-acetals and -aminals disclosed in
GermanAuslegeschrift No. 2,306,248, which are also decomposed by
the photolysis products of the aryl-halogen-methyl-s-triazines
according to the invention.
Compositions in which molecules which essentlally infLuence
the chemical and/or physical properties of the composition by their
presence, are directly or indirectly converted into smaller molecules
by the action of actinic radiation, normally show an increased solu-
bility, tackiness orvolatility in the exposed areas. These areas may
be removed by sultable measures, for example by dissolving them
away in a suitable developer liquld. In the case of copying composl-
tions, such systems are referred to as "positive-working systems".
The novolak condensation resins found suitable for many
positive-working copying compositions were also found suitable and
advantageous as an addltive to the copylng compositions according to
the invention and comprising compounds capable of being decomposed
by acids. These resins, in particular the more highly condensed
resins contalning substituted phenols as formaldehyde condensation
- 20 partners, promote a strong differentiat1On between the exposed and the
unexposed areas of the layer during development. The type and quan-
tlty of the novolak resin added may vary with the purpose for which the
; composition is intended; novolak proportions between 30 and 90 per
cent by weight, especially between 55 and 85 per cent by weight,
based on the solids conten~ of the composition, are preferred. In
addition thereto, various other resins may be added, besides the novo-
laks, vinyl polymers, such as polyvinyl acetates, polyacrylates,
polyvinyl ethers, and polyvinyl pyrrolidones, which, in turn, may be
. .
35~3 Hoe 77/K 017 (K 2543)
modified by co-monomers, being preferred. The most favorable ratio
of these resins depends on practical requirements and on their Lnflu-
ence on the conditions of development; normally, it does not exceed
20 per cent of the novolak component. For speclal requirements as
regards flexibllity, adhesion, gloss, etc., minor amounts of other
substances, such as polyglycols, cellulose derivatives, e.g. ethyl
cellulose, wetting agents, dyestuffs, finely divided pigments, and,
if necessary, UV absorbers may be added to the light-sensitive com-
- position.
Preferably, development is effected with the aqueous alkaline
developers customary in the art, to which small proportions of organic
solvents may be added. -
The supports mentioned in connection with the photopolymeriz-
able compositions also may be used for the positive-working copying
. .
compositions. In additlon, the silicon and silicon dioxide surfaces
known from microelectronic processes may be used.
; The quantity of photoinitiator contained in the positive-working
copylng compositions also may vary widely, depending on the sub-
stance used and the type of the layer. Favorable results are obtained
wlth proportions ranging from about 0.05 per cent to about 10 per cent,
based on the total solids content, proportions between 0.1 and 5 per
cent being preferred. In the case of layers of more than 10~m thick-
ness, it is recommended to use a relatively small quantity of acid
donor.
In principle, any electromagnetic radiator er~litting waves of a
wavelength up to about 600 nm is capable of inltiating reactions of the
described type in the compositions according to the invention. The
preferred wavelength range extends from 300 to 500 nm.
- 12 -
$~3 Hoe 77/K 017 (K 2543~
The great number of aryl-halogen-methyl-s-triazines wlth ab-
sorption maxima deep in the visible range of the spectrum and absorp-
tion ranges extending beyond 500 nm render it possible to select a
photoinitiator whlch is optimally adapted to the light source employed.
In principle, however, a sensitization is also possible. Suitable
light sources are, for example:
Tubular lamps, pulsed xenon lamps, metal-halide-doped high
pressure mercury vapor lamps, and carbon arc lamps. In addition
thereto, the light-sensitLve copying compositions according to the
invention may be exposed in conventional pro~ectors and enlargement
apparatuses, to the light of metallic-filament Ibmps, or by contact
exposure under ordinary incandescent bulbs. Alternatively, coherent
laser beams may be used for exposure. Shortwave lasers of adequate
energy output, for example argon lasers, crypton-ion lasers, dyestuff
`- lasers, and helium-cadmium lasers emitting between 300 and 600 nm-were found suitable for the purposes of the present invention. The
laser beam is directed by a given, programmed line and/or screen
.
movement .
As a further possibility, the layers according to the invention
~` 20 may be differentiated by irradiation with electron beams. The copying
; compositions according to the i~vention - the same as numerous other
- organic materials - may be thoroughly decomposed and cross~linked
- ~ by electron beams, so that a negative image is formed after the unex-
.
posed areas have been removed by a solvent or by exposure -without an
- original iollowed by development. In the case of an electron beam of
lower intensity and/or higher operating speed, however, the electron
beam causes a differentiation toward a higher solubility, i.e. the ;
irradiated areas of the layer may be removed by a developer. The
13
H oe 7 7/K 0 17 (K 2 5 4 3 )
most favorable conditions may be easily ascertained by preliminary
tests.
Preferably, the radiation sensitive compositions according to
the present invention are used for the manufacture of printlng forms,
especially offsetl halftone gravure, and screen printlng forms, but
also in photo resists and in so-called dry resists.
The Eollowing Examples illustrate the invention in detail.
First, the preparation of a number of new aryl aarboxyl1c acld nitrlles
is described which sesve as starting materials from which the photo-
initiators are prepared. Then, the preparation of some halogen-methyl
substituted s-triazines is described which were found sultable as
acid-forming compounds in the copying compositions according to the
invention. They were designated as Compounds Nos. 1 to 20 and
will be referred to in the Examples by these numbers.
. .
In the Examples, the relation between parts by weight and
parts by volume corresponds to that between grams and milliliters. ~` ;
Percentages and propor~ions are by weight unless otherwise stated.
PreParation of Aryl Carboxylic Acid Nitriles
The following aryl carboxylic acld nitriles R-CN, which have
not yet been disclosed in the literature of the prior art, were prepared
analogously to the instructions given in "Chem. Ber.", 100, 2719
(1967), from the corresponding carboxylic acids R-COOH, or directly
from the alkoxy aryl compounds R-H, by reaction first with chloro-
sulfonyl isocyanate and then-with dimethyl formamide.
-- 14 --
. . .
~5;l~3 Hoe 77/K 017 (K 2543)
Table 1
Nitriles R-CN
Nitrile R Melting Pt. Starting
No. (C) Substance
__ _
4-(2-ethoxy-ethoxy)~ oil; distilled in a R-H
naphth-l-yl bulb tube; air bath
130 to 140C/ 5 -
10-4 Torr
2 4,7-dimethoxy- 109 - 110 R-H
naphth- l -yl
3 4, 5 -dimethoxy- 12 0 . 5 - 121 ~ 5 R-H
naphth-l-yl
4 5-methyl-6-methoxy- 74 - 85 ~-H
naphth-2-yl
4-methoxy-anthrac- 143- 145 R-H
' l-yl
6 5-methoxy-naphth-1-yl 89 - 91 R-COOH
* Crude product; purification at the aryl-s-triazine stage.
The starting substance of Nitrile No. 1, 1-t2-ethoxy-ethoxy~-
naphthalene, with a melting point of 91 - 95 C/0. 002 Torr, was ob- ;
tamed by alkylating l-naphthol with ethyleneglycol monoethyl ether/
p~toluene sulfonic acid chloride, according to the msthod described
in "Monatshefte Chem.", 82, 588 (1951).
Preparation of bis-Trichloromethyl-s-Triazines
Gaseous hydrochloric acld is introduced, at a temperature be-
tween 0 and 5C, into a solution of 29.1 grams of l-ethoxy-naphthal-
ene, 100 grams of trichloroacetonitrile, and 1.65 grams of aluminum
tribromide whlle the solution is agitated. After about 2 hours, the
mass in the flask has solidified; introduction of the gas and cooling
are discontinued. When the reaction mixture is heated to room
~ .
1 5
, . ,,,, , ., : ~
H oe 77/K 017 (K 2543)
temperature, it becomes partly llquid again; it is cooled agaln to 0 C
and gaseous hydrochloric acid is aga1n introduced for two hours. After
the mass has again spontaneously heated and was cooled to 0 - 5 C,
and after further introduction of gaseous hydrochlorlc acid for 2 hours,
the then solid mass is allowed to stand overnight at room temperature, - -
Thereafter, it is dissolved in methylene chloride and shaken out ln a
small quantlty of water. After the solution has been dried over sodium
sulfate and the solvent has been removed under reduced pressure, a ~;
crude product is obtained which is freed irom unreacted portions of the
starting material and from tris-trichloromethyl-s-triazine, which is formed
by a side reaction, ~y distillation in a bulb tube ("kugelrohr") apparatus ~ ;r
(air bath: 110 - 130C/0.1 Torr). 24.1 grams of a residue are ob-
tained which consists of almost pure 2-~4-ethoxy-naphth-1-yl)-4,6-
bis-trichloromethyl-s-triazine, which, after recrystallization from
diethyl ether, ha s a melting point of 154.5 - 156.5 C .
The aryl-bis-trichloromethyl-s triazines listed in Table 2 are
prepared analogously, the crude products being in some cases puri-
fied by crystallizatlon, in others by additional flltration over silica
gel, using methylenechlorid0 as the solvent and eluent.
Table 2
Aryl-bis-trichloromethyl-s-triazines corresponding to Formula I wherein
n = m = o and X = Cl
Photo- Melting Pt. Longwave Absorption
initiator R (C) ~ M~l~num
1 ) Naphth-1-yl 128-129 363 4.05
2 2-Methoxy-naphth-1-yl 162-165 368 3.59
3 4-Methoxy-naphth-1-yl 181.5-183 388 4.33
4 5-Methoxy-naphth-1-yl 154-156 399 3.87
4-ethoxy-naphth-1-yl 154.5-156.5 388 4.34
-- 16 --
p~
Hoe 77/K 017 (K 2543)
Table 2 - continued:
_ . _
Photo- Melting Pt. Longwave Absorption
initiator R (C ) Maximum
No . ~ maX (n m~ _ log
6 4,5-Dimethoxy-naphth- 165- 167 416 4.16
1 -yl
7 4,7-Dirnethoxy-naphth- 136-137 404 4.27
l -yl
8 4-(2-ethoxy-ethoxy)- 103-105 388 4 34
naphth- 1 -yl)
9 ~) Naphth-2-yl 210-211.5 367 3.52
.
1-Methoxy-naphth-2-yl 132-134.5 371 3.71
11 3-Methoxy-naphth-2-yl 173-175 322 4.29
385 (sh) 2.98
12 6 -M ethoxy-naphth -2 ~yl 191.5 - 192 351 4.27
374 4.2~
13 5-Methyl-6-methoxy- 211-214 390 4.20
naphth-2-yl
14 Quinol-3-yl 201-204 317 4.28
Benzopyran-3-yl 185-188.5 405 4.04
16 4-Phenyl-phenyl 149.5-151.5 332 4.49
i
` ` 17 Dibenzothien-3-yl 243.5-244.5 355 4.30
18 Phenanthr-9-yl 181-184.5 363 4.05
19 4-Methoxy-anthrac-l-yl 221-225 446 4.24
Acenaphth-5-yl 204-205 396 4.18
~) The melting point of 216-218C given in "Bull. Chem. Soc. Jap. "
42, 2924 (1969) could not be confirmed.
+~) Literature: 2}0 - 212 C .
Example 1
- An electrolytically roughened and anodized aluminum plate
i5 whlrler coated with a coating solution comprising
6.7 p.b.w. of trimethylolethane-triacrylate,
6.5 p.b.w. of a methylmethacrylate/methacrylic acid
copolymer with an acid number of 115,
3~8 Hoe 77/K 017 (K 2543)
0.12 p.b.w. of photoinitiatorNo. 5,
64.0 p.b.w. of ethyleneglycol monoethyl ether,
22.7 p.b.w. of butyl acetate, and
0.3 p.b.w. of 2,4-dinitro-6-chloro-2'-acetamido-
5'-methoxy-4'~ hydroxyethyl~
cyanoethyl)-amino-a~obenzene,
so that a layer weighing 3 to 4 g/m2 results after drying. The plate is
then provided -with a 4~m thick protective layer of polyvinyl alcohol
(Mowiol 4/88, Hoechst AG), exposed for 30 seconds from a distance
of 110 cm to the light of a 5 kW metal halide lamp under a line/screen
original, and developed with a 1.5 per cent solution of sodium meta-
silicate.
A negative image of the original is thus obtained. A printing
run with an offset printing plate made in this manner was stopped after
200,000 copies of good quality had been printed.
~2
This example describes the manufacture of a negative-working
dry resist. A coating solution oi
24.9 p.b`.w. of a copolymer of 30 p.b.w. of metha-
crylic acid, 60 p.b.w. of n-hexylmethac- ~;
rylate, and 10 p.b.w. of styrene,
16~1 p~bow~ of the reaction product of 1 mole of
2, 2, 4-trimethylhexamethylene-diisocya-
nate and 2 moles of hydroxyethylmethac~
rylate,
0.41 p.b.w. of ~riethyleneglycol dimethacrylate,
0~58 p~b~wo of Photoinitiator No. 3,
Q~ll p~b~wu of the dyestuff used in Example 1, and `
5 7 ~ 9 p . b . w . of m~thyl ethyl ketone
-- 18 --
Hoe 77/K 017 ~K 2543)
is -whirler coated on a polyethylene terephthalate film in a manner such
that the dry layer weighs 25 g/m . The resulting material is laminated
in a commercial laminator, at 120 C, onto a support composed of
insulating material provided with a 35 ~,m thick copper layer. After ex-
posing the material for 60 seconds under an original whlch contains a
continuous tone step wedge, besides line and screen motifs, using a
5 kW rnetal halide lamp as the light source as in Example 1, and de-
velopment wLth 0.8 per cent sodlum carbonate solution, a negative
image of the line and screen motif and steps 1 to 5 of the step wedge
remain in the form of a relief, while step 6 of the step wedge ls par~
tially corroded.
The resist layer is resistant to etching processes, for example
-~ with ferric chloride solutions, and the action of electroplating baths
used for the production of circuit boards,
' Exam~le 3
A mechanically roughened aluminum plate is whirler coated
with a solution of
4.3 p.b.w. of a phenol-formaldehyde novolak
(mel ~ing range 110 - 12 0 (~, accord-
ing to DIN 53181),
10.6 p.b.w. of N-vinyl carbazole,
0 . 24 p .b . w . oi 2- (p-dimethylaminostyryl)-benzthiazole,
0.25 p.b.w. of Photoinitiator No. 7, and
84.6 p.b.w. of methyl ethyl ketone.
After drying a light-sensitive layer of 1-~m thickness results.
The plate is imagewise exposed for 8 seconds as described in Example
l; during exposure, the color shade in the image areas of the layer
changes from yellow to orange red. By moving the plate to and fro in
- a developer solution composed of
-- 19 --
35~3~ Hoe 77/K 017 (K 2543)
0.6 p.b.w. of NaOH,
0.5 p.b.w. of Na2SiO3 S H2O,
1.0 p.w.b. of n-butanol, and
97.9 p.b.w. of completely desalted water,
the unexposed areas of the layer are removed within 75 seconds.
When the plate is wiped over with greasy ink, the exposed areas of
the layer accept ink, so that the plate may 3~e used for printing on an
offset machine.
Example 4 ~ ;
Example 3 is repeated, except that in the coating solution the
styryl color base is replaced by the same quantity by weight of the
cyanine color base 2~ cyan-3-(3-ethyl-2-benzthiaæolylidene)-
-~ propen-l-y~l-quinoline and that the Photoinltiator Mo. 7 is replaced
by the same quantity of Photoinitiator Mo. 13 and that a polyester film
is used for coating.
By imagewise exposing the material for 16 se~conds as de-
scrlbed in Example 1, the color of the image areas changes from an
. , ,
initlal light red to deep violet.
By wiping over with the developer used in Example 3, the
non-image areas are removed. A negati~7e lmage of the orlginal is
thus produced.
This method may be used for the production of color proofing
films.
Example 5
A mechanically roughened aluminum plate is whirler coated
with a layer of the following composition from a 10 per cent methyl
ethyl ketone solutlon:
-- 20 --
~3~3 Hoe 77/K 017 (K 2543)
48.3 p.b.w. of an epoxy resin ~obtained from epi
chlorohydrin and Bisphenol A, epoxy
equivalent weight 182-194), ~ ;~
48.3 p.b.w. oi a cresol-formaldehyde novolak
: (melting range :L05-120C according
: to DIN 53181 ),
~ 2.9 p.b~w. of Photoinitiator No. 8, and
.` 0,5 p.b.w. of Crystal Violet. ~ -
By 60 seconds' imagewise exposure as in ~ixample 1 and 40
seconds' development with the developer used in Example 3, a nega~
,
tive image of the original is obtained in which the non-image areas
., ; .
are free from scum.
If the epoxy resin is replaced by the same quantity of the above
~ . :
~ stated novolak, a negative image becomes briefly vislble during devel- ~
.: ~
~ opment, but the resistance of the layer to the developer is so poor that ~ ~
, : :
the entire layer Is dissolve:d from the support within 30 seconds . ~:
Example 6 ~ `~
~. :
This example shows howlayers containlng the new photoinitia- ~;
tors and compounds which are split up by acids, are imaged by means
20 . of electron beams:
About 2~m thick layers of the following composition
74% by weight of the novolalc used .in Example 5,
22% by weight of the compound split up by an acid,
3.8% by weight of the photoinitlator, and
0.2% by weight of a dyestuff
are applied to mechanically roughened aluminum and are then irradiated
with 11 kV electron beams~ The Irrad1ated areas are solubilized under
the condltions stated in Table 3.
-- 21 --
!
35~8 Hoe 77/K 017 (K 2543)
For development, either the developer used in Example 3 or the
following developer solution is used:
5.5 p.b.w. of sodium metasilicate 9 H2O,
3.4 p.b.w. of trisodium phosphate 12 H2O,
0~4 p~bow~ of anhydrous mono-sodium phosphate, and
90.7 p.b.w. of compLetely desalted waterO
Table 3
Photo- Compound SpLlt up Irradiated Developer Developing
initiator by an Acid Energy accordin~ Time
No. _ (Ioule/cm2) to Example (secQnds)
3 polyacetal obtained 1-10-10 6 45
from benzaldehyde and
triethyleneglycol
polyacetal obtained 1-15 10 3 10
from propionic alde-
hyde and triethylene-
glycol
8 ~is-diphenoxy methyl- 1-30-10 2 6 30
ether of polYqlycol 200 __ _ _ _
Example 7
For the preparation of a re-enlargement plate, a solution was
prepared from
4.0 p.b.w. of the novolak stated in Example 5,
1.2 p.b.w. of bis-(5-ethyl-5-butyl-1,3-dioxan-
2 -yl) -ether of polyglycol 2 0û
0.2 p.b.w. of Photoinitiator No. 12,
0.01 p.b.w. of Crystal Violet, and
94.6 p.b~w. of methyl ethyl ketone
and applied, on a centrifuge, to a brushed aluminum plate.
The plate is exposed for 3 minutes under a positive transpar
ency from a distance of 65 cm, using a projector of type Leitz Prado
(f = 85 mm, 1: 2.5) with a 150 watt lamp as the ligh1: source. By
-
- 2~ -
Hoe 77/K 017 (K 2543)
immersion in the developer used in Example 6, an enlarged positive
copy of the black and white line image on the positive transparency is
ok-tained within 30 seconds. The copy may be reproduced by printing
in a small offset pres s .
Similar results are obtained lf the above bis~orthoester is re~
placed by the same quantity of the polymeric acetal of benzaldehyde
and triethylene glycol and Photoinitiator No. 12 is replaced by Photo-
initiator No. 20.
Example 8
A coatlng solution composed of
4.0 p.b.w. of the novolak used in Example 5,
1.2 p.b.w. of the reaction product of 2,2,5,~-
tetrahydroxymethyl-cyclopentanone ;
`' and ortho-formic acid trimathyl ester, ~
0.2 p.b.w. of Photoinitiator No. 1, ;
0.01 p~brw~ of Crystal'\tiolet, and
94.b p.b.w. of methyl ethyl ketone -
is whlrler coated onto an electrolytically roughened and anodized
aluminum plate in a manner such that a dry layer weight of 2 . 0 g/m
results, and the plate is imagewlse exposed for 40 seconds under the
conditions stated in Example 1 -whereupon a pronounced bluish violet
- bluegreen contrast becomes visible.
By wiping over with the developer used in Example 6, the
plate is developed to a positive image of the original.
In a test run, 140,000 copies of good quality were obtained
from the offset printing plate produced.
Comparable results are obta~ned by replacing Photoinitlator
No. 1 by the same quantity of Initiator No. 6, ~o. 4, or No. 18, or
by a mixture of two or all of these Initiators.
5~B8 Hoe 77/K 017 ~K 2543)
Example 9
A positive-work~ng photoresist of high layer thickness is pro-
duced as follows:
29.6 p.b.w. of the novolak used in Example 5,
8.9 p.b.w. of the bis-(5-ethyl-5-butyl-1,3-
dioxan-2-yl)-ether of 2-ethyl-2-
butyl-propane-dlol,
0.12 p.b~w. of PhotolnltiatorNo, S, and
2.1 p.b.w. of modified silicon glycol (a commer-
cially available coating auxiliary)
are dissolved in
59.28 p.b.w. of butan-2-one.
This solution is applied, by means of a wire bar No. 40, to ~;
the cleaned copper surface of the composite material used in Example
2. By storing the material for 12 hours at room temperature, the sol-
vent is substantially evaporated. The plate Ls after-drled for 15
minutes at 70C by infrared radiation.
A 70~m thick resist layer is thus produced which is image-
wise exposed for 80 seconds under a line orlginal, using the S kW
metal halide lamp of Example 1 as the light source, and then may be
developed within 40 seconds by spraying with a 0. 8 per cent sodium
hydroxide solution,
ExamPle 10
The efficiency of the new photoinitiators as acid donors is
investigated by incorporating them in a standard composition:
0.5 gram of the novolak used in Example 5,
0.15 gram of the bis-orthoester used in Example 9,
-- 24 --
Hoe 77/K 017 (K 2543)
0.025 gram of photoinitiator, and
0.012 gram of Crystal Violet, dissolved in
12.5 ml of methyl ethyl ketone,
are whirler coated onto plates with electrolytically roughened and
anodized surfaces to a layer thickness of 1.5 to 2~m and then image-
wise exposed for 40 seconds under the conditions stated in Example 1.
Layers containing Photoinitiators Nos. 2, 9, 10, 11, 15, 16,
17, and 19 can be developed wlthin 30 seconds by moving them to and
fro in the developer used in Example 6, while the layer containing
Photoinitiator No. 14 requires 1 minute's development with the devel-
oper used in Example 3. In all cases a positive copy of the original
, is obtained,
ExamPle 11
Aluminum plates with an alectrolytically roughened and ano-
dized surface are whirler coated with a solution of
4.7 p.b.w. of the novolak used in ~xample 5,
1.4 p.b.w. of the compound capable of be1ng
s~lit up by acid,
~- Q.23 p.b.w. of photoinitiator,
0.02 p.b.w. of Crystal Vlolet, and
93. 05 p,b.w. oi butan-2-one
in a manner such that, after drying,a layer of about 1.7~m thickness
results. The layers are imagewise exposed over all spectral lines with
an argon laser of 25 W output, the laser beam being focussed by a
lens on a spot with a diameter of 5 ~m. By varying the recording speed
of the laser, the sensitivity of each combination is determined. By
treatment wlth the developer used in Example 6, the exposed areas of
,
~3~, Hoe 77/K 017 tK 2543)
the layers are dissolved away within 15 to 90 seconds. The trace of
the laser may be brought out even more distinctly by inking the unex~
posed areas w1th greasy ink.
The following maximum recording speeds were determined:
Combination Recording Speed
~m~sec . )
Propionic aldehyde/triethyleneylycol poly- 50
acetal - Photoinitiator No. 12
Benzaldehyde/1,5-pentanediol polyacetal - 75
Photoinitiator No. 5
Bisorthoester, according to Example 9 - 25
Photoinitiator No . 5
I O , , . _ _ . _ _ _
It will be obvious to those skilled in the art that many modifi-
cations may be made within the scope of the present invention without
departing from the spirit thereof, and the invention includes all such
modifications,
'
.
2 6
