Note: Descriptions are shown in the official language in which they were submitted.
~58943 S 1 53
,
LIGHT-SENSITIVE COPYING COMPOSITION COMPRISING
A SYNERGISTIC INITIATOR SYSTEM
The present invention relates to new light-sensitive copying
compositions which may be commercially used either in the forrn of solid
layers or as a liquid mass and which are composed substantially of at
Ieast one polymeric binder, at least one ethylenically unsaturated polym- ; -
erizable compound, and a photoini'ciator system comprising at least two
photoinitiators. "Ethylenically unsaturated polymerizahle compounds"
;,~
according to this invention mean low molecular weight polyfunctional
monomers capable of addition polymerization as well as multiply unsatu~
rated high molecular weight compounds subject to photo-crosslinking. ;
Substances of the most varied classes of compounds have been
disclosed as photoinitiators for the photopolymerization of unsaturated - ~ ~ -
compounds, - - `
. . ~
Thus, it is known to use as photoinitiators, for example, chal-
~;~ kones, aromatic ketones or diketones, multi-nuclear quinones of the
anthraquinone or phenanthrenequinone type, benzanthrone derivatives or
aza-benzanthrone derivatives, aromatlc nitro compounds, heterocyclic
,
~ ~ six-membered compounds, such as acridines, phenazines, quinoxalines, ~ ~ ~
,
2 0 ;~ ~ pyryllum compounds and thia-pyrylium compounds, heterocyclic five~
membered compoundz, e.g. benzthiazolez, benzoxazoles, orbenzimida~
zoles, and organic dyestuffs, e.g. eosin, methylene blue or fuchsin.
Due to the construction of their molecules, these photoinitiators
very often can be~ used only for particular layers and substantially lose
their effectiveness when used in other polymerizable oompositions. In i~ ;
many cases, it is necessary to use a considerable quantity of an initiator
in order to achieve high cross-linking densities, and in these cases the `
:
applicability of the initiator is limited by its solubility In the light~
sensitive ~opying compositions.
Lack of compatibility is frequently observed when the copying
composition is subjected to substantial variations in temperature under
, ",,, " . ,., ,, 1 a~
..
, . . . . . .
., . , ,: ., : . . : , :
1058943 K-2441
unfavorable conditions of storage or shipping. Under these conditions,
exudation and/or crystallization of the photoinitiator may occur, which
results in a loss of light-sensitivity, sometimes considerably impairs
the adhesion of the tight-serlsitive layer, and substantially detracts from
the shelf-life of the copying composition.
It is known, from German Offenlegungsschrift No. 2,060,575,
to use unsaturated ketones of the type
H H H H
I I I ~, ~
R - (C=C) n-C-(C=C)rrl ~ R'
''': ~'
as photoinitiators in copying compositions containing monomers with ~ ~
vinyl or vinylidene groups. The light-sensitivity of layers oontaining ~ - ~
only such compounds is not entirely satisfactory, even if relatively large
quantities are employed, nor does thelr use in combination with special
compounds known to be suitable photoconductors from German Patent
No. 1,137,625, e.g. appropriately substituted multi-nuclear heterocyc-
lic compounds having groups displaying an electron-donor effect, meet-
the demands for high light-sensitivity combined with high cross~linking
density made on photoresist materials which must be resistant to
.
corrosive electroplating baths.
It is~ the object of the present invention to provide a highly
effective photoinitiator system of good compatibility with all other in~
- ,
gredients of the copying composition, which is particularly suitable for
the photopolymerization of low molecular weight monomeric acrylates~
and alkyl acrylates, and which imparts to the copying composition of
the present invention a very good light-sensitivity under practical con-
ditions in combination with a high cross-linking density.
~ .
It has been found that the practical light-sensitivity of copying
compositions containing, in addition to a binder and monomeric acrylates
'' ',: .
-- 2 --
....
.. . , : - . :
... . .
. , . . " ~ ' ' : , ' . : ' -' ': ' . ,
l~S!394~
or alkyl acrylates, compounds corresponding to the general Forlmula I (below)
as photoinitiators, synergistically may be lncreased by adding a second
photoinitiator of the type of compounds identified by For ~la II (below) in ~-
which the carbonyl group i5 linked to a p-dialkylamlno aryl group, either
~ .-
directly or by a vinyl group.
~ he present invention is concerned with a light-sensitive copying
composition comprising at least one polymeric binder, at least one ethylen-
ically unsaturated compound having at least two double bonds capable of add-
ition polymerization~ and a photoinitiator system, in which the photoinitiator ~ ~:
system used is composed of at least two components I and II, wherein
I is at least one compound of the general For~mula I
10 N- - Ro
~2 ~ 1 iJ 3
7 0 5
wherein
is 0, S, or ~ ,
is hydrogen, a sa~urated or unsaturated unsubstituted hydrocarbon
radical with 1 to 6 carbon atoms, a saturated or unsaturated hydro- .
,~
carbon radical with 1 to 6 carbon atoms which is substituted by ~!
member(s) selected from the group consisting of hydroxyl, alkoxy,
alkoxycarbonyl, acyl, acyIoxy and halogen, an aralkyl group with ~.
7 to 10 carbon a~oms~ an acyl group with 2 to 18 carbon atoms, or
a polyalkyleneoxide group of the general formula -(CaH2a-O)n- ~:
a 2a (CaH2a O)n-CaH2a-OCH3 ~herein a is an integer from 2
to 4 and n is an integer ~rom 1 to 10, and ~; .
R2 is hydrogen, an aIkoxy group, an alkyl group with 1 to 6 carbon
atoms, or halogen~ and ~ :
II is at least one ccmpound of the general Formula II ~-~
,
. , : ...... ; ,. , : ; : - ,:
, , . .,; ,, : ~ .. . : ,,
K-2441
R 3 H H
\N-~-(C = C)x - l - R5
wherein
R3 i5 an alkyl group with 1 to 6 carbon atoms,
R4 is an alkyl group with 1 to 6 carbon atoms, and
R5 is hydrogen, an alkyl group with 1 to 6 carbon
atoms, an alkoxy group in which the alkyl group
has 1 to 4 carbon atoms, an aryl. group with 6 to
12 carbon atoms, or a dialkyl amino styryl group, ~ ..
~ . ~
and wherein
x is 0 or 1.
The compounds corresponding to the 6-oxo-anthra-(1 ,9-cd)py-
razole-2(6H) type (Formula I; Ro = NR1) may be substituted in the 2
: ~ position (=R1) by hydrogen, lower unsubstituted alkyl groups with 1 o 6,
preferably 2 to 4 carbon atoms, hydroxyl, alkoxy, alkoxy carbonyl, pre- .
ferably ethoxy carbonyl, acyl or halogen, preferably chlorine or bro- . :
mine, or by substituted alkyl groups with 1 to 6, preferably 2 to 4 car-
~; bon atoms, the numbers 1 to 6 designating the number of carbon atoms `
: ~, `
arranged in a straight chain in the substituted alkyl group.
Further suitable substituents in the 2-position are: the allyl
group, an aralkyl group with 7 to lO carbon atoms, preferably benzyl or ~ ~ .
toluyl, or an acyi group with 2 to~ 18 carbon atoms. Among the acyl ~ ~
groups, acetyl to stearyl, benzoyl, methoxybenzoyl, ethoxy benzoyl, : r~ ~'
'
methyl benzoyl, benzsulfonyl, or tosyl are preferred, ~ -
The substituent R2 in the six-membered ring of the basic anthra~
cene structure (Formula I; Ro = O, S, NR1) may be in the 7, 8, 9, or 10
position, preferably in the 10-position, and may be hydrogen, halogen,
- 4 -
lS8943 K-2441
.~ ' . '
preferably chlorine or bromine, or alkoxy, preferably methoxy or ethoxy, :
or alkyl with 1 to 6 carbon atoms, preferably methyl or ethyl. ~ .:
Suitable substituents :for R3 and R4 in cornpounds of the type of
Formula II are lower unsuhstituted alkyl groups with 1 to 6, preferably
1 to 4 carbon atoms, which may be arranged in a straight chain or
branched; R3 and R4 may be the same or different :~
The substituent in R5 may be hydrogen, a lower al-kyl group with
1 to 6, preferably 1 to 4 carbon atoms, an alkoxy group, preferably
methoxy, ethoxy, isopropoxy, propoxy or butoxy, an aryl group with 6
., ; .
to 12 carbon atoms, preferably phenyl, or a substituted aryl group, pre~ ~::
ferably tolyl, dialkylaminophenyl, or anisyl, or a dialkylamino styryl
group. -
The index x may be 0 or 1, and preferably is 0.
:
~ : Compounds corresponding to the Formula I, whereinRo is N-R1,
. .
may contain any of the followlng groups as substituents in the 2-position~
R1 = -CH2-CH2-OH ~ -
-CH2-fH-CH3
.
OH
CH2-CH-CH2OH
: OH .
-CEI 2 -CH-CH2 -CH2-OH
OH ~
. .
-CH2-CI H-CI H-(~ H2H
OH OH ~-
-CH2-CH-C H
1 3 7 -~: .
OH
-(CH2)4-CH2OH
-CH -CH -OCH
.
-- 5 -- :
. , .
, . . . . .
~513943 K-2~41
R - - C H -C H -O C H
(cEI2-cH2-o)n-cH2-cE~2oH and n = 1-10
(CEI2 CH2-O)n-CH2-CH20CH3 and n = 1-10
-CH2-C--C-CH20EI
CH3 Cl H3
- CH2-C-O -CEI2-C-OH and n= 1 10
H H ~ :
. .
CH3 1 3 ~ ~ :
_ CH -C-O n-CH2-C-OCH3 and n = 1-10
_ _ H
-CH2-CI H-CH2-0CO-cH3 ~ ~
'~ .
-CH2-CI H-CH2-0cO-c2H5
cH2-cH-cH2-oco-cl5H3
OH ; ;~
-C~12-CH-CH2-OCC)-CH=CH2
OH
-CH2-~H-CH2-OCO-c=cH2 ;~
H
R
-CH2-fH-C~I2-OCO- ~
OH wherein ~3 = H, OCH3, OC2H5,
-CO-NH- ~ ~ CH3 to C4Hg, halogen
- 6 -
:
~ '' ,
:: ,
. ... .. ... .. .
: . .. ,. : ' :. -
105~3943 K-2441
Rl = -CO-NH-R4 WhereinR~4=cH3~ C2H5 toCgHls, ;
-CH2-co-NR5R6 wherein R5; R6 = H~ CH3, C2H5' ~-
CH C~ wherein R = OCH3 OC2H5 halogen
-CH2-C~
-CH2-CH=CH-R8 and R8 = CH3, C E~
-CO -CH=CH2 - v:
: ~ 10 ~ 1 2 ~ `'' ''~
~ :
: -cO-cF3
~ C H 2 - C H 2 ~ C O -R g
CH2~CO-R9 and R9 = CH3 ~ C2H5 to C H1 3
and wherein
:R2 = H, ~OCH3, OC2H5 or Cl.
. ..
The following Tables T and II list preferably used~a~ompt)unds of
the~typè of;~ormula I and Formula II~
T A B L E~
20: :~ No~. ~of the~ Substituent Substituent ~ : Substituent-
: Compound ~ Ro R} ~ ~ R2
. - --. ~ . ~ . .. ...
2 ~ S :~ H
:: ~ I 3 NR~ H : ~ , : H
4 . NRl ~ CO-C6H5 H: ; ~ ~ -
1 CO~C6H4 p~OCH3: H
6 : NRI C-C17H36 :~ H
7 NRl C-C7H15 ; H
,
- 7 -
~ .
, ~
: , ,,, : ,
. . ,
10513943 K-2441
No. of th~ ~ubstituent Substituent Substituent
Compound Ro Rl 2
8 NR1 CO-C3H7
19 NR1 CO-C2H5 H
CO-CH3 H ~ 5.
11 NR1 $o2-C6H4 P 3 H
12 NR1 4 9 H
13 NR1 i-C4Hg H
14 NR1 Allyl . H
NR1 Benzyl H
I 16 NR1 CH2-C:OOC2H5 - H
17 NR1 CH2-CO-C6H5 H
.
18 NR1 CH2CH (OH)CH2CH3 H
19 N R ~ H
NR1 CO-C6H5 OC2H5 ;
21 NR1 CO-C6H4 P OCH3 2 5 ~ .
l 22 NR1 17 35 C2H5 : : .
: I 23 NR1 CO c7Hls OC H
: I 24 NR1 CO-C2H5- C2H5
:~ ~ I 25 ~ NRl CO-CH OG H ~ :
20~ l 26 NR1 Benzyl oC H
27 NR1 CH -CO-O-C H OC2H5
28 NR1 CH -CO-C H ~ OC H
29 NR1 CH2-CH(OH)-CH2-CH3 OC2H5 . -
NR H Cl
,.
31 NR1 CH2-CH(OH)CH2CH3 Cl
32 . NR1 CH2-CH(OH)-CH2Cl Cl
33 N~1 CO-CH
-- 8 -- ::
10$8943 K 2441
T A B L E II
No. of the Substituerlts Substituent
Compound R3 R4 R5 x : :
`:
II 3 3 p-C6H~N(CH3)2 ~ ~
II 2 CH3 CH3 0CH3 0 : :
II 3 CH3 CH~ C~I2CH3 ;
II 4 3 3
II 5 3 3 OC4H9 0
II 6 3 H3 CH
Il 7 CH3~ CH3 2 5 0
II : 8 CH3 CH i-C3H7 ~
. .
II g CH3 CH3 C6H5 O
II 10 CH3 CH3 - H O
Il 11 3 3 CH=CH-C~H4-P-M(CH3)2
II 12 CH3 CH3 ~ ~ C6H5
13 CH3 CH3 p-C6H40CH3
4 ~2H5 C2Hs C6H5 - O
II 15 C2Hs ~ ~C2H5 p-C6H4 N (G2H5)2
The mechanism of the synergistic effect is still unknown. Sur~
prisingly, it was found that, by combining compounds correspond~ing to `
Formula l wlth compounds corresponding to Formula lI~in accordance
with the present invention, an increase of the light-sensitivity is achiev~
ed which in some cases exceeds the sum of the individual effects of the ~ d
components used by one order of magnitude or more, as expressed, e.g.,
by the number of fully reproduced steps of a step wedge.
Although all compounds of Formula II contain a p-dialkylamino-
,~ .
phenyl group, the presence of this group alone is not sufficent to pre-
dict a synergistic effect for compounds of this type.
.` .
_ 9 _ :
.
~ 58~4~ K-2 441
This is demonstrated by the fact, that the compound I 18, for
example, does not form a synergistic photoinitiator combinatic>n with
the following compounds A, B, or C. The effectiveness of the compound ~:
I 18 is either not increased by these compounds (A, B~, or is even re-
duced (C):
H H CH
A: ~ ~C = C- ~3 -N/
CH
B~/ 3
CH3 ~ k
. ~ _ ..
C: ¦ ~I = C -~ )-N/ J (3
~: I : C2H5 3
Thus, the mar3ced increase in the photoinitiator effect of the
compounds of Formula I when combined with compounds o:E Formula II
is the more surprising.
The synergistic effect is very pronounced at all mixing ratios j : - .
as can be clearly seen from Example 4 below.
The proportions by weight of the compounds of Formula I and
Formula Il used according to the lnvention vary within wide limits and
range from about 2: 98 to 98: 2. Proportions between 80: 20 and 20: :
80 are preferred, and withln these limits proportions from 40: 60 to
60:40.
The copying compositions according to the invention comprise,
as the essential components, binders, liquid and/or solid polymerizable .;~ ~ .
organic cGmpounds, and mixtures of photoinitiators of the above describ-
ed types corresponding to Formula I and Formula II.
~.
- 10
: . .
.. . ..
l~S8943 K-2441 3
i
Suitable monomers are ethylenically unsaturated compounds, for
example commercially available ac~lic and methacrylic acid esters,
such as those of diethylene glycol, triethylene glycot, tetr~ethylene
glycol, and polyethylene glycol, and of trimethylolethane and trimethy-
lolpropane, further diglycerol diacrylate, gualacol glycerol ether di-
acrylate, neopentyl glycol diacrylate, 2,2-dimethylol ~utanol-(3)-
diacrylate, unsaturated pentaerythritol esters, as described in U. S.
Patent No. 3,261,686, reaction products of trimethylol propane, alkyl-
ene oxide and acrylic acids ormethacrylic acids in accordance with U.
S. Patent No. 3,380,831, and acrylates and methacrylates of polyesters
'
containing hydroxy groupsO The latter compounds and other monomers
suitable for use in the photopolymer layers according to the invention
are described, for example, in U. S. Patents Nos. 2,760,863, and
3,060,023.
The monomers containing urethane groups known from German
Offenlegungsschrift 2, 064, 07 9, and the biuret group (~ C - ~ - c ~
r
-containing monomers known from Gerrnan Offenlagungsschrift
2, 361, 041 may be used in tha same manner.
As can be seen from this ~list of compounds, the present inven~
20 ~ tion is not limited to the use of a specific polymerizable monomer; all
- that is necessary is that the monomer be at least twice ethylenicatty
unsaturated and capable of additlon polymerization. If multiply unsatu~
rated high molecular weight compounds are used, they must be either iS~ ~ ~
capable ~of photo-crosslinkmg, or must be capable of addition polymeri- `
zation with a low molecular weight monomer. The following unsaturated
compounds, for example, are suitable for use in light-sensitive copying
compositions:
Polyvinyl cinnamates and prepolymers of unsaturated esters,
e.g. the prepolymer of diallyl isophthalate, or the polymeric allyl
- 11 -
~058943 K 2441
imides disclosed in German Offenlegunysschrift No. 2,203,732, and
the polyvinyl acetals containing extra-linear vinylidene groups accord- ;
ing to U. S. Patent No. 2,902,710.
If commercially available or, preferably, home-made monomers
are used, they normally contain small amounts ~about 50 to 100 ppm~ of -~
an inhibitor in order to pre~7ent thermally induced polymerization.
If the copying compositions according to the invention are to
withstand extreme conditions of storage without deterioration, the quan~
tity of inhibitor may be increased to 1 per cent, calculated on the ~ ;
weight of the monomerused ~ `
The following compounds may be used as thermal inhibitors, for
example: -
p-Methoxyphenol, hydroquinone, alkyl-substituted or aryl~
substituted quinones and hydroquinones, tertiary-butyl catechoL, pyro~
gallol, copper resinate, naphthyl amine, ,B-naphthol, coppe~-(Ij~chloride,
2,6-di-tert.-butyl-p-cresol, phenothiazine, pyridine, nitrobenzene, `~
and dinitrobenzene, p-toluquinone, chloroanil, and thiazine dyestuffs,
for example Thionine Blue G.
Further, the photopolymerizable copying compositions may com-
prise, in known manner, one or more binders, for example solvent-
soluble polyamides, polyvinyl acetates, polymethyl~meth)-acrylates,
polyvinyl butyrals, cellulose ethers or cellulose esters, polyalkylene -
ethers, condensation polymers of glycols with dibasic acids, copolymers
.~ ' ?
of styrene and maleic anhydride which are soluble or at least swellable
or softenable in alkaline solutions, copolymers of ethylene and maleic
anhydride or of alkyl methacrylate and methacryliG acid according to
German Offenlegungsschrift No. 2,064,080, terpolymers of styrene,
alkylmethacrylate, and methacrylic acid according to German Offenle-
gungsschrift No. 2,363,806, copolymers of methyl methacrylate and
- 12 ~
~L051~$~43 K-2~41
N-(p-toluene-sulfonyl)-carbAmic acid-(~-methacryloxy)-ethylester
according to German Offenlegunysschrift No. 2,027,466, further malei-
nate resins, terpenphenol resins, and others.
Inasmuch as aqueous alkaline developers are frequently used for
development, binders are preferred which are either alkali~soluble or
softenable In aqueous alkaline solutions. Examples of such binders are
copolymers of styrene and maleic anhydride and copolymers of alkyl
methacrylate and methacryllc acid, terpolymers of styrene, alkyl
methacrylate and methacrylic acid, maleic resins, and the copolymers
disclosed in German Offenlegungsschrift No. 2,205,046.
Further, plasticizers, adhesion promoters, hydrogen donors,
oxygenabsorbants, dyestuffs, pigments, colorcouplers, UV-absorbing
substances, and sensitometric regulators may be added to the copying
compositions accordir~g to the invention
The type and quantity of these ac!ditives are determlned by the
fieid of application for which the copying composition is destined,
` Further, care must be taken that the substances added do not absorb an `~
undue proportion of the actinic light required for the initiating process
and~thus ~educe the practical light-sensitivity of the copying cornposi~
tion.
Suitable plasticizers are, for example, dibutyl phthalate, diiso- ~
: : .: .~.
octyl adipate, nitrate esters, alkyl and aryl phosphate esters, chlori- ;
.~. .
nated paraffins, glycols and aliphatic polyols, If good storability at
.
high atmospheric moisture is to be ensured, water-insoluble plasticiz-
ers are preferably used.
Adhesion promoters are added in all cases, where the light-
sensitive copying compositions are to be exposed to extreme stress, for `
example when they are to be used as photoresist materials, The follow-
'~
ing adhesion promoters are advantageous: monomeric or polymeric
13-
~LOS89~ K-2441
organic silanes, nitrogen-containin~ heterocyclic compounds, such as
those disclosed in U. S. Patents No. 3,645,722, Mo. 3,622,234, and
No. 3,827,908; further heterocycLic mercaptans according to Gerrnan
Offenlegungsschrift No. 2,028,773, mercapto alkanic acid anilides
according ~o German Offenlegungsschrift No. 2,443,821, and mercapto
alkanic acid esters aceording to German Offenlegungsschrift No~
2,~48,~50.
Suitable hydrogen donors, which may be used in known manner,
are, for example, substances eontaining aliphatic ether groups or cyclic
~-biearbonyl compounds. In some cases, the binder or the polymeriz-
able substanee may perform this function, provided they contain an
unstable hydrogen atom.
Further, the photopolymerizable eopying eompositions aeeording
to the invention may comprise dyestuffs and/or pigments, whieh may be
added in order to enhance the contrast or to solidify the layer. Suitabte
dyestuffs are diselosed, for example, in U. S. Patents Nos. 3~218,167,
and 3,884,693.
The-ligm-sensitive eopying eompositions Qf the invention further
may eontain UV absorbers serving as anti-halation filters, Suitable
non eoloring substances are deseribed, for example, in German Offen- ;
legungsschrift No. 2,243,182.
Within the seope of the present invention, the following propor-
tions of the essential eomponents of the light-sensitive copying eompo-
sition are preferred, the percentages stated being by weight and being ~ ~;
ealculated on the total solids content of the compositions:
binder: 15 - 99 per cent
monomer: 1 - 75 per cent
photoinitiator mixture: 0,1 - 10 per cent
hydrogen donor: 0.5 - 1 0 per eent
~L05~3943~ K-2441
plasticizer: 0.0 - 15 per cent
adhesion promoter: 0.0 - 15 per cent
dyestuff or pigment: 0.0 - 30 per cent.
For commercial purposes, the light-sensitive copying composi-
tions according to the invention may be used in the form of solutions or
dispersions, i.e. as so-called photoresist compositions, which the
customer himself applies to a particular support - this being the usual `~
procedure, for example, for chemical milling, for the preparation of ~
printed circuits or stencils, or for making plates, screen printing sten- --
eils and the like - followed by drying, e~posure and imagewise devel~
opment. In this c~ase, the ingredients of the light-sensitive copying
;~ somposition are dissolved in a suitable solvent. Su~table solvents are
alcohols, ketones, esters, ethers, amides, hydrocarbons, and the like.
The partial ethers of glycols or of keto-alcohols have proved to be par-
ticularly favorable solvents; the ehoice of the solvent is, however,
substantially determlned by the binder seleeted.
.,-:
Alternatlvely, the light-sensitive copying composition aceording
to the invention may be marketed in the form of a solid photopolymeriz~
able layer on a base material, which is used for the preparation of print
ing forms, relief images, eteh resists, stencils, matrices, screen print-
ing forms, single eopies and the like. A particularly important appliea~ -
~tion is their use as storable presensitized printing plates for plano~
..
graphie, relief, or intaylio printing.
The base materials are eoated with the inventive compositions
irom appropriate organie solvents or solvent mixtures, using easting,
spraying or immersion proces ses .
Suitable supports are, for example, magnesium, zinc, copper,
mechanically, chemically or electrechemically roughened aluminum,
- 15 -
. . .
., . . , , ! , ,, ' ' , : ;
' ' ' : ' ' , ' , . ' ' ' . : ' ,
~58~343 K-2~41
anodized aluminum, steel, but also polyester or acetate films, "Perlon"
gauze etc., the surfaces of which may be subjected to a pretreatment, ~
where necessary. The base material may serve either as the ultimate - ;
support or as an intermediate support from which the light-sensitive
eopying composition is transferred, by lamination, onto the workpiece
to be processed. If thick photopolymer layers are to be produced, i.e.
of a thickness of several tenths of a millimeter, the copying composi-
tion according to the invention may be kneaded without dissolution, for
example in a three-roll mill, and then hydraulically pressed onto the
support for one minute at a pressure of 30,000 to 50,000 kp and a
temperature of 90C, for example.
If erosslinking is effeeted solely by polymerization of the ethy-
lenieally unsaturated monomers, it is normally of advantage to proteet
the light-sensitive copying composition aecording to the invention,
during exposure, from access to atmospheric oxygen, because oxygen
tends to intercept the radicals forming within the layer and to deaetivate
them. Suah an exelusion of oxygen is aehieved in a simple manner by ;
providing an oxygen-impermeable barrier iayer, as diselosed, for ex-
ample, in German Offenlegungssehrlften Nos. 1,572,153, and
2,036,585.
If the light-sensitive copying composition contains a high molec~
ular weight eompound which is capable of a photochemical crosslinking
reaetion, so that erosslinking is not exclusively or preponderantly
eaused by the low molecular weight aerylates or alkyl aersrlates, no
such barrler layer is necessary, beeause in this ease photo-erosslinking
results in the desired differentiation between exposed and exposed areas
even in the presence of oxygen.
The recording material prepared with the light-sensitive copying
eompositions according to the invention may be used, on the one hand,
,:
- 16 -
,, . : . ' . . ~,
.,,.,: ., :
3L05~3943~ K-2441
for the preparation of images on suitable support or receiving sheets,
and, on the other hand, for the preparation of relief images which may
be used as printing forms, screens, photoresists and the like. In addi-
tion, it is possible for the ligh-t-sensitive copying composltions of the
present invention to be used for the preparation of UV-hardening lac-
quers which may be used for surface protection, or for the preparation
of UV-hardenin~ printing inks which do not dry physically and do not
cross-link chemically, with formation of cross-connections by oxygen
action. Drying is by a photochemical process and thus is particularly
rapid and ecologiccally safe.
Printing forms, screens, etch resists and the like may be pre-
pared from appropriate copying materials according to the inventlon in
the customary manner, i.e. after exposure under a suitable original the
non-image areas, which have retained their solubility, are removed by
treatmentwith suitable solvents, e.g. aqueous alkaline solutions.
Alternativaly, development may be caused by other methods,
utilizing other known physical differences between the hardened image -~
areas and the unhardened non-ima~e areas, for example differences in
the melting points, in the tackiness, in the adhesivenss, in the opeical
transparency, or~others. ~ ~
The invention will be further illustrated by reference to the fol- ~;
lowing examples.
Unless otherwise stated, all quantities are by weight. ;
The relation between parts by weight and parts by volume is the
same as that between grams and milliliters.
Example 1
140.0 p.b.w. of a copolymer of 85.8 p.b.w~ of methyl- ~ ;,
methacrylate and 12.5 p.b.w. of methacrylic acid ~-
with an average molecular weight of 35,000 and
.
:, ' ,, :
~OS13~43 K-2441 ~ ~
an acid number of 86, ;~
140.0 p.b.w. of pentaerythritol-triacrylate, and
1.5 p.b.w. of tri-L4-tmethyl-phenylarnillo)-phen
methyl acetate
are dLssolved in
1400.0 p.b.w. of ethylene glycol monoethyl ether.
A series of solutions of the above composition are prepared, and
in each case either 7.0 p.b.w. of one initiator, or a mixture of 3.5
p~bow~ of an initiator according to Formula I and 3.5 p.b.w. of an ini-
tiator according to Formula II are added.
The solutions are filtered and then whirler-coated, at 100 revo-
. .;. , .
luations per minute, onto an electrochemically roughened aluminum foil ~ ~
and dried. ; ~--
After drying, the sample plates are so coated with an aqueous ~;
solution containing
2 . 0 p.b.w. of carboxy methyl cellulose, ~ ~:
1.0 p.b.w. of cane sugar,
1.0 p.b.w, of saponin, and ~;
0.12 ~ p.b.w. of sorbic acid, in
267.0 p.b.w. of water,
that the dry layer weighs about 0.6 g per square meter. Then each sam-
-. ,,
ple is exposed for two minutes under a 21-step half-tone wedge with a
density range of 0.05 - 3.05 and density increments of 0.15 (Kodak:
Photographic Step Tablet No. 2) . The light source used is an 8 ,000 W
"Xenokop" spot arc lamp (distance: 72 cm).
For removal of the non-image areas, the plates are wiped over
for 30 seconds with a developer having a pH of 11.9 and being composed
of ~
`.1 . . .
, ~
- - 1 8 -
.
:. ' ' ' -' '
, .
,. ., . , , . , ., . . : . :
... .. . . . . .. . .
lC~51~943 K-2441
1.5 p.b.w. of sodium metasilicate nonahydrate,
0 . 3 p . b . w . of polyethylene glycol 6, 000,
0.06 p.b~w. of levulinic acid, and
0.03 p.b.w. of strontium hydroxide octahydrate in
100.0 p.b.w. of water,
and then rinsed down with water.
If the copying layers are processed in this manner, l:he fully re-
produced steps of the Kodak step wedge are a measure for the starter
activity of the initiators or initiator mixtures tested, i.e. the higher
the number of steps reproduced, the higher the practical light-sensitivity.
The following Table III lists the number of fully reproduced
steps of the step wedge for each of the initiator combinations tested,
adjacent partially colored transition steps being disregarded. The light-
sensitivities of two adjacent steps of the step wedge differ by a factor ~-
of~. Step 0 of the step wedge corresponds to an optical denslty of
0.05 (inherent absorption oE the film material).
T A B L E III -
Initiators Number
Type I Type II Test No. of Steps
.
,.
I 9 1 1
14 2 1
I15 3 3
II 1 4
II 3 5 0
II 6 6 0
II 9 7 0
II15 8 1
9 II 1 9 7
g II 3 10 8
.. ..
- 19 -
91.058g43 K-2441
Initiators Number
Type I Type II Test No. of Steps
9 II 6 11 9
9 II 9 12 6
9 II 15 13 3
14 II 1 14 6
14 II 3 15 10
:, ~ ?
14 II 6 16 10
14 II 9 17 7
I 14 II 15 18 5
II 1 19 8 -
I 15 II 3 2 0 8
~ - .
~ ~ I 15 II 6 21 8 ;~
~,
II 9 2 2 9
1 15 Il 15 23 4 ;;
Example 2
This example shows the influence of different compounds of
Formula II on a specific compound of Formula I tComPound No. 1 18). ;~
-,-
140~ 0 p~b~wo of a copolymer of 85 p.b.w. of methyl ~ -
methacrylate and 15 p.b.w. of methacrylic acid ;
with an average moiecular weight of 43,000 and
an acid number of 86,
140.0 p.b.w. of ~trlmethylol ethane triacrylate, a d
1 . 5 p . b, w . of a blue azo dyestuff, obtained by coupl~
lng 2 ,4-dinitro-6-chloro-benzene-dla~onlum salt
with 2-methos~y-5-acetylamino-N-cyano-ethyl~
N~hydroxy-ethyl aniLine, `~
:,:
are dissolved in
1400.0 p.b.w. of ethylene glycol monoethyl ether
'. ' '
- 20- ~
. - , . ,,: , , -.. ,. . , ... ,. , ~:,
.. .. . . .... . . . .
~LOS 5~9' L3 K-Z441
A series of such solutions are prepared and to each ~f thern
either 5 . O p.b.w. of one initiator, or 2 .5 p.b.w. of the initiator
corresponding to Form-lla I 18 and 2.5 p.b.w. of one of the initiators
corresponding to Formula II are added.
The solutions are filtered and whirler-coated, at 100 revolu-
tions per mlnute, onto an electrochemically roughened and anodized
aluminum foil. -
The dried samples are coated with a solution of
3.5 p.b.w. of polyvinyl alcohol and
1.0 p.b.w. of sodium lauryl-ether-sulfate in
9 6 . 5 p . b . w . of water ~ -
which has a ~riscosity of about 16 cp and are then dried. Further pro-
cessing is as described in Example 1. Table IV indicates the relative
light-sensitivities of the samples obtained.
T A B L E IV
Initiators Number
Type I Type II Test No. of steps
.... - - ~ ,.~,. ~ '.
18 2 4
Il14 2 5 0
2 0 II11 2 6 0 ~I~
II2 27 no image -
II15 28 0 ;;
: ",
II12 2 9 0
II13 3 ;
II6 31 0 ~`
.. .
18 II14 3 2 7
18 II11 3 3 4
18 II2 3 4 12
1 8 II15 3 5 8
- '' ~; :
- 21 -
i[)S13~43 K-2441
Initiators Nurnber
Type I Type II Test No. of steps :
18 II 12 36 5 .
18 II 13 37 6
18 II 6 3 8 11
Example 3
This example serves to show the influence of one initiator com-
pound of Formula II upon different initiator compounds of Formula I.
The tests were carried out analogously to Example 2. Several com~
pounds were used as initiators corresponding to Formula I, and the ini-
tiator of Formula II was the compound numbered II 1.
The results are listed in the following Table V. - ~:
T A B L E V ~ ~:
Initiators Number .~ ~
Type I Type II Test No. of Steps ~ : :
3 9
,.~, . ' ;-
~: I 9 40 5 ~ . :
: :
17 41 4 `.
: I 18 42
2 0 I 2 8 4 3 0 . ;
Il 1 44
II I 45 10
9 II 1 4 6 12 ,' ~
17 II 1 47 12 ~ ~ :
18 II 1 48 11
2 8 II 1 4 9 8
:. ;
Example 4
This example shows how wide the limits in which the mixing ratio
.:
~: ,
- 22 - :
.. -
,, ., , , , . ., .- , , . , , ., ., ~ . -
: ., :.. - - ,: , , : , . . . .
,, . : . , , ,. . , :.: , :
: ., ~. . ,.. i ,... . . ..
:, , :..... . , :,
J ~5~43 K - 2441
of the two components of the initiator system may be varied without 105~
ing its synergistic effect.
140.0 p.b.w. of a copolymer of 85 p.b,w. of methyl
methacrylate and 15 p.b.w. of methacrylic acid
with an approximate average molecular weight of
~3, 000,
140.0 p.b.w. of-trimethylol ethane triacryLate, and
1.5 p.b,w. of the blue dyestuff used in Example 2
are dissolved in ;
1400.0 p.b.w. of ethylene glycol monoethyl ether~
A series of such solutions are mixed in each case either with 5 . 0 ~ ~-
parts by weight of the initiator numbered I 1 or the inltiator numbered
II 1, or with 5 .0 parts by weight of a mixture of these two initiators~
The tests are carried out exactly as the tests described in Examples ~ `
2 and 3. The results are listed in the following Table VI.
T A B L E VI
. ~ ,
Initiators Number
Type l Type II Test No. of Steps
.
~. , .
5 . 0 p . b . w 3 9
2 0 4 . 0 " 1 . 0p . b . w . 5 0 8
3.0 " 2.0 " 51 9
2.5 " 2.5 " 45 10
2 . 0 " 3 . 0 " 5 2 1 1
l.0 " 4.0 " 53 10
O.5 ~ .5 ~ 54 9
., . ~
0.25 " 4.75 " 55 8 -
5.0 " 44 1
. .
- 23 -
. : , . . :: :, :~
,: ,~
.: .
lalS8943 K-2441
Examele 5
In this example, compounds accordiny to Formula I carrying
different substituents in the 10-position ~re compared.
140.0 p.b.w. oE a copolymer of 87.5 p.b.w. of
methyl methacrylate and 12.5 p.b.w. of
methacrylic acid with an average molecular
weight of 35,000,
140.0 p.b.w. of trimethyLol ethane triacrylate, and ;;
1.5 p.b.w. of the blue dyestuff described in
Example 2
are dissolved in
1400.0 p.b.w. of ethyleneglycol monoethyl ether.
A series of such solutions are mixed either with 5.0 p.b.w. o~
one initiator, or with 2 .5 p.b w. each of two initlators . -
The samples are evaluated as in Example 1 and the results are
listed in the following Ta~le VII.
:: -
T A B L E VI I
:, -: .-~ :.
. ,
Initiators Number
Type I Type II Test No. of Steps -
:~
2 0 1 1 8 S 6 ~ ~ 1
18 II 1 5 7 9
29 58 no Smage
..... ..... ....... ... ..... ..... ... ... .... ....... ... ... .......... ... .... ... .............. .......... ., . ~.
2 9 II 1 5 9 4
31 6 0
31 II 1 61 6
II 1 6 2
Example 6
This example serves to illustrate that even in light-sensitive
copying compositions containing multiply unsaturated high molecular
~' ~
- 24
.,' ~' . `:
.. . .
, . ,,, . : . , ~ ,
, -: . . . . . ... . . .. .
:, . , , :, . . -
- - ~L05S~ L3 K-24 41
weight compounds the synerglstic effect of the initiator systems accord-
ing to the present lnvention is fuLly effective.
A series of solutions are prepared comprlsing
360.0 p.b.w. of diallyl isophthalate prepolymer and
90.0 p.b.w. of pentaerythritol triacrylate in
2 9 0 0 . 0 p . b . w . of 2 - me thy l- 2 - methoxype ntanone -4
Each of these solutions is mixed either with 16.0 p.b.w. o a
single initiator, or with 8. 0 p .b.w. each of the two initlators of For-
mula I and Formula II to be used in admixture, and the solutions are
then agitated until the solid substances have completely dissolved.
The solutions are filtered and whirler-coated, at 100 revolutions per
minute, onto a mechanically roughened aluminum foil. The coated
aluminum foils are dried for 15 minutes at 50C and are then exposed ; ~ "
in a vacuum frame un~er a 21-step half-tone step wedge (Kodak: ;~
.~ :.
Photographic Step Tablet No. 2), using an 8000 W xenon spot arc tamp ~-
from a distance of 72 cm.
After exposure, the samples are bathed for 60 seconds in 1,1 ,l-
trichloroethane and then sprayed with clean solvent. The plates are
then treated for 45 seconds, with the aid of a cotton pad, with the
; etching solution disclosed in German Offenlegungsschrift No. ;
l ,940,280, and comprising~
80.0 p.b.v. of gum arabic (14Be),
12. 0 p.b.v. of phosphoric acid (85%),
0.2 p.b.v. hydrofluoric acid 150%),
0.5 p.b.v. of H2O2 (30%)~ and
7.3 p,b.v. of water. ~ -
- The image areas are then inked up with greasy ink. The relative
light-sensitnities are compared in the same manner as described in
Example 1.
' ~-
- 25 -
. .
: -., . : ., ., ,, ~
105;894~3 K-~441
The results of the evhluation are listed in the following Table
VIII.
T A B 1. E VIII
Initiators Number
Type I Type II Test No. of Steps . . :
XI 1 (8.0 p.b.w.) 63 8
II 1 (16.0p.b.w.) 64 8
2 6 5 4
. 2 II 1 66 13 :~
I 4 6 7 7
4 II 1 68 14 . ~;
6 6 9 6 ~ ` ~
,~ . ~. ; .. .
6 II 1 7 0 15
. ~,. . . .
7 71 5
7 II 172 13
I 8 73 : 8 : ~ `
.:. : ~ ,.
8 II 174 13
9 7 5 8
.~. ... .
9 II 17 6 15
2 0 I 12 7 7 3
12 II 17 8 14
13 7 9 3
13 II 180 13
81 ~ 8
- I l S II 1 8 2 15
1 6 8 3 7
16 II 184 16
17 85 7
.: :.
- 26 -
.
'. .. ' ',. : . . .
: . . :
105!394,3 K-2~1
Initiators Number
Type I Type II T~st No. of Steps
17 II 1 86 15
24 87 3
24 II 1 88 13
2 9 8 9 3
2 ~ II 1 g O 13
3 0 9 1 1 ~; ;
3 0 II 1 9 2 14
1 33 93 6
3 3 II 1 9 4 1 6
.
Example 7
The solution described in Test 32 (Table IV) comprising ;
140.0 p.b.w~ of a copolymer oE 8S p.b.w. of methyl
methacrylate and 15 p.b.w. of methacrylic acid,
140.0 p.b.w. of trimethylol ethane triacrylate, ~ -~
1.5 p.b.w. of the blue dyestuff described in Example 2,
2,5 p.b.w. of Compound I 18, and
2.5 p.b.w. of Compound II 14, in
:.-,, .:
1400.0 p.b.w. of ethylene glycol monoethyl ether, ~ `
, :
~is filtered and whirler-coated, at 100 revolutions per minute, onto an
: .
electroahemically roughened and anodized aluminum foil ~
The coated plate is dried in a circulating-air dryer and is then again
coated with the aqueous solution of polyvinyl alcohol and sodium lauryl
ether sulfate described in Example 2 and dried. -
After exposure under a negative original in an 8 k~ xenon exposure
apparatus from a distance of 72 cm, the plate is developed with the aid
of a cotton pad, using the alkaline developer solution described in
,;,
,' . ,' ; ..
- 27 -
!':
" . ' ' "' ' ' ,'. ~ ~, ' ~' ' '
1051~943 K-2441
Example 1 containing sodium metasilicate, polyethyleneglycol 6000,
levulinic acid, and strontium hydroxide in water. After wiping over
with 1% phosphoric acid solution, the image areas of the plate are
inked up with greasy ink. ;
The plano~raphic printing plate thus produced may he used for `
.~ . .
printing several tens of thousands of flawless prints in an offset ~ ~-
' ,: ., ,'
machlne .
Example 8
, ~. ~ . .
A solution of ;
10140.0 p.b.w. of a copolymer of 85 p.b~w. of methyl ~ ;
methacrylate and 15 pob~w~ of meehacrylic acid
;;; ~ (molecular weight approximately 43,000),
140.0 p.b.w. oftrimethylolethanetriacrylate,
1.6 p.b.w. of the blue dyestuff used in Example 2, !:`
2.5 p.b.w. of Compound I 9, and
2.5 p.b.w. of Compound II 2 in
1400,0 p.b.w. of ethyleneglycol monoethyl ether
is fil~tered and whirler-coated, by means of a centrifuge, onto the~
chromium surface of a brass plate provided with a duli chromium plat~
ing,~whereupon the plate is dr~ed.
The plate is then ~coated with the aqueous solution of polyvinyl
alcohol and sodium lauryl ether sulfate described in Example 2 and
dried again.
After a 2 minutes' exposure under a positive original in a copy- ~
ing frame (using an 8 kW xenon spot arc lamp from a distance of 72 cm), ~ ~-
the plate is developed with the aqueous alkaline developer solution i
: , `
used in Example 1, by wiping with a cotton pad.
Then, the plate is etched with a commercially available chrom-
ium etch composed of 42.4% of CaC12, 9.8% of ZnC12, 10.8% of HCI,
28 -
58943 K-2~41
and 37% of HzO so that the chrornium layer is etche(l away within two
minutes. After rinsing with water, the copying layer is removed by
immersion of the plate in acetone, the image is rinsed again, wiped
over with 1% dilute H3PO~L, and finally inked up with greasy ink. .
A flawless multi-metal printing plate for planographic printing
is obtained from which very lony runs may be printed.
Example 9
In Example 12 of German Offenlegun~sschrift No. 2,203,732,
there is disclosed the preparation of a photo-crosslinkable compound
obtained from poly-(methyl vinyl ether/maleic anhydride) and allyl ~;
a mine .
600.0 p.b.w. of this polymer,
100,0 p.b.w. of trimethylol ethane triacrylate, `~
8. 0 p.b.w. of Compound I 1, and
. . .:
8.0 p.b.w. of Compound II 1 - ~ ~;
are dissolved in -
1400.0 p.b.w. of methyl ethyl ketone,
and the solution is applied to a "Nylon" fabric (about 80 meshes per
centimeter) and dried. The coated fabric is ima~ewise exposed Eor 4 ~ - .,
minutes under a positive original, using an 8 kW xenon lamp at a dis-
tance oE 72 cm, and the resulting image is devetoped with acetone . A
useful silk screen is thus obtained. -
Example 10
A coating solution is prepared from
400.0 p.b.w. of a styrene/maleic anhydride co-
polymer,
200. 0 p .b.w. of an c~-methylstyrene/vinyltoluene co~
polymer
-' ' ~
- 29 - ~
, . . . .
i5~ 3 K-2441
25.0 p,b.w. of a polyvinyl butyrat with an average
molecular weight of 30,000 to 35,000,
500.0 p.b.w. of trimethylol propane trlacrylate,
1.0 p.b~w. of Compound I 1, and
4.0 p.b.w. of Compound II 1, in
2000.0 p.b.w. of methyl ethyl ketone and
200.0 p.b.w. of ethyleneglycol monoethyl ether,
"~....... ~ , : ~
and filtered.
A 35~m thick copper foil laminated to a base of phenolic resin ¦
paper is coated with this solution. After drying, the layer is covered
with a 1 to 2 ~3~m thick polyvinyl alcohol layer. j
The coated copper plate is exposed for 2 minutes under a ne~a- ¦
1. : . .
tive original showing a circuit diagram, using an 8 kW xenon lamp. l, -
Then it is developed with the aqueous alkal~ne developer used ¦
in Example 1 and etched at 50C with an aqueous FeCl3 solution.
The cop~per is etched away in the bared areas and a printed cir-
cuit of the type used in the electrical lndustry is obtained.
Exa mp l e 11
700, 0 p.b.w~ of a terpolymer of 25 p.b.w~of meth-
~ acrylia acid,~ 62.5 p.b.w. of n-hexyl-methac~
rylate, and 12.5 p.b.w. of methyl-methacrylate
as~a binder~
560.0 p.b.w. of the monomerdescribed }nExsmple l
of German Offenlegungsschrift No . 2, 064, 079
(reaction product of 2,2,4-trimethylhexsmethyl-
ene-diisocyanate and ~-hydroxy-ethyl-methacrylate),
15.0i p.b.w. of triethyleneglycol dimethacrylate,
2.0 p.b.w. of the blue dyestuff used in Example 2,
5.0 p.b.w. of Compound I 28, and
;~
- 30-
.; . ~ . -
.. .
.,, . : . ' :
~058943 K-2441
. ~ '
5.0 p.b.w. of Compound II 6
are dissolved in
2500.Q p.b.w. of methyl ethyl ketone ancl
200.0 p.b.w. of ethyl alcohol. ~ ;~
The solution is filtered and coated onto a polyethylene tere-
phthalate support in such a manner that the resulting clry layer weighs
32 g/m2
By means of a commercially available laminating apparatus, the
eoated film is laminated onto the copper surface of a composite material ,~
eomposed of layers of copper and hard paper.
After a two minutes' exposure of the laminate (xenon lamp, 8 ~ ~ I
kW) under a positive original showing a circuit diagram, the protactive
film is pulled off and the image of the circuit diagram is developed with
a 0.~ per cent sodium carbonate solution.
The eopper circuit paths are reinforced by electrodeposition and ~,~
then covered, also by electrodeposition, with a lead-tin layer.
The resist layer is removed by immersion in acetone. Finally,
the bared copper is etched away in a FeCl3 solution, thus completing
the photomechanical production of a printed circuit.
20 ~ It will be obvious to those skilled in the art that many modifi~
eations may be made within the scope of the present invention without ;;
departing from the spirit thereof, and the invention includes all such
:: :
modifications.
-- 31 --
'
, . .' ,: :
.
