Note: Descriptions are shown in the official language in which they were submitted.
~ 39';~ ~La.<~Z ~ - 2 5 0 6
This invention relates to a negative-working light-sensitive
copying composition, which is, in particular, suited for the preparation
of high-quality presensitized planographic printing plates and for the
production of relief images, color separations, etch resists, stencils,
screen printing forms, individual copies, etc. The invention further
relates to a copying material produced using this light-sensitive copy-
ing composition and also to a process for the preparation of a litho-
graphic printing plate.
Negative-working planographic printing plates, the copying layers
of which function as stencils or etch resists after imagewise exposure -
and differentiation have been in use for a long time, and they are
commercially available as plates for a reversal process, sometimes
called "reversal plates" or "deep etch plates", and in the form of pre-
sensitized bimetal and trimetal plates. On the other hand, solutions
or emulsions of light-sensitive copying compositions are available
which may be used for coating single metal, bimetal and trimetal car-
riers, so that a planographic printing plate desired for a particular
purpose can be prepared on the spot at the processing plant.
A commercially available reversal plate is processed as Eollows:
The reversal plate which is composed of a light-hardenable copy-
ing layer on a metal plate serving as a carrier is first exposed to light
under a positive original. Then the unexposed and thus non-hardened
image areas are removed by-wiping with a developer. The parts of the
carrier surface laid bare by wiping are treated with a metal etching
solution, i.e. they are deep etched. After drying, the entire surface
of the plate is covered with a thin lacquer layer which is receptive to ~`
printing ink; the plate is again dried and dyed with a greasy protective
ink . For removing the exposed and hardened areas of the copying layer,
':
7~22 K-2506 r
together with the lacquer and ink adhering thereto, the plate is treated
with a suitable stripping solution. By this treatment the lacquer por- ~
tions adhering directly to the etched carrier are not affected. Follow- -
ing wiping of the bared carrier surface, e.g., with dilute phosphoric
acid, the reversal plate is ready for printing.
However, the reversal plates heretofore used show various disad-
vantages during processing. Deep etching of the plate surface after
developing is an expensive process step which, in addition, does not
produce the required uniformity of depth and degree of roughening when
large areas are treated, so that good results are not obtained with
sufficient reliability.
Further, stripping of the known planographic printing plates
yields relatively poor results and is time-consuming, especially when
there is a very strong bond between the lacquer and the hardened copy-
ing layer areas, so that an attack of the stripplng solution is made
dlfflcult or even impossible. This means that aggressive mixtures of
potassium permanganate and hydrogen pero~ide must be used as
stripping agents.
It is, therefore, difficult to match the copying layer and the
processing agents in such a manner that optimum results are obtained.
Originally, the copying layers used with reversal plates, bimetal
plates and trimetal plates contained chromates as sensitizers and gum
arabic, fish glue or bone glue as colloids. However, layers of this
composition have the disadvantage that they possess poor storability
because of the so~called "dark reaction". An identical instability is
observed in chromate-sensiti7ed polyvinyl alcohol layers.
Improved storability resulted from the use of synthetic water-
soluble colloids, such as polyvinyl pyrrolidone, polyvinyl alcohol,
L~;~ K- 25 06
polyvinyl methyl ether etc. as binders combined with diazo resins, i.e.
condensation products of p-diazodiphenylamine and paraformaldehyde.
However, hardening obtained on exposure of these layers did not always
prove adequate. The hardened image areas showed only a limited resis-
tance to the great number of processing steps following exposure. Fur-
ther, these layers which wera composed of solely water~soluble colloids
were susceptible to finger marks, in particular in case of high atmos-
pheric moisture.
In German Offenlegungsschrift No. 1,772,947, planographic
printing plates for the deep etch process are described, in which special
hardenable resins, e.g., a modified copolymer of acrylic acid/acrylic
acid amide or a polymethacrylate are used together with diazo resin
compounds serving as light-sensitive substances.
These plates have the disadvantage that after development accord-
ing to the known processes it is necessary to deep etch the carrier sur-
face by an additional etching step ln order to improve the adhesion of a
lacquer which is applied to the carrier surface in a subsequent process-
ing step and thus to ensure long runs. As a consequence, processing
of the plates is time-consuming and expensive. It is also a disadvan-
tage that the hardened copying layer only inadequately repels the appli-
ed lacquer; it forms a relatively strong bond with this lacquer so that
stripping is made difficult.
It is an object of the present invention to provide a light-sensitive
copying composition which is, in particular, suited for the preparation
of high-quality, presensitized negative-working planographic printing
plates and which permits a simplified processing of the planographic
printing plates, so that good results are repeatedly obtained. It is fur-
ther an object of the invention to provide a complete and deep cleansing
K- 2 5 0 6
of the highly porous carrier surface in the course of development of the
exposed planographic printing plate, so that an etching operation sepa-
rate from development can be omltted.
This object is achieved by the negative-working light-sensitive
copying composition of the invention. It comprises as a light-sensitive
component a diazonium salt condensation product and as a binder a
water-soluble synthetic polymer and an acrylic resin insoluble in water,
which is soluble or at least swellable in an alkali. In addition, the
copying layer may contain pigments, dyes, plasticizers, color couplers,
and similar known additives.
The water-soluble synthetic polymer used for the preparation of
the light-sensitive copying composition according to the invention is a
copolymer of an N-vinyl-N-alkyl carboxylic acid amide, the alkyl and
the carboxyllc acid radicals of which contain 1 to 6 carbon atoms each,
and a C3 to C16 alkyl acrylate havlng a branched or straight-chain
alkyl radical.
The following N-vinyl compounds are exemplary of the N-vinyl-
N-alkyl carboxylic acid amide:
Vinyl-N-methyl formamide, vinyl-N-ethyl formamide, vinyl-N-propyl
formamide, vinyl-N-butyl formamide, vinyl-N-methyl acetamide, vinyl-
N-ethyl acetamide, vinyl-N propyl acetamide, vinyl-N-butyl acetamide,
vinyl-N- methyl propionamide, vinyl-N -ethyl propionamide, vinyl-N-
propyl propionamide, vinyl-N-butyl propionamide, vinyl~N-methyl-n-
butyramide, vinyl-N-ethyl-n-butyramide, vinyl-N-propyl-n-butyr-
amide, and vinyl-N-butyl-n-butyramide.
Vinyl N-methyl acetamide is preferred.
The second component of the copolymer, an alkyl acrylate, is,
e.g., one of the followlng monomers:
71~ K- 2 5 0 6
n-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, n-octyl
acrylate, 2-ethyl hexyl acrylate, and 3,5,5-trimethyl hexyl acrylate.
2-ethyl hexyl acrylate is preferred.
In general, copolymers containing N-vinyl-N-alkyl carboxylic
acid amide in an amount ranging between about 80 and 99.5 per cent by
weight are suitable. Particularly advantageous are copolymers contain-
ing about 90 to 99 per cent by weight of vinyl-N-alkyl carboxylic acid
amide .
The water-soluble synthetic polymer is, especially, a copolymer
of vinyl-N-methyl acetamide and 2-ethyl hexyl acrylate. Preferably, it
has a K-value of between 45 and 50, measured as a 1 per cent solution
ln methanol. It is soluble in water, in acids and in organic solvents,
e.g., alcohols, ketones, polyglycols and ethylene glycol methyl ether
acetate; in aqueous alkaline solutions swelling is observed. It 1s, to
a large extent, compatlble with the acrylic resins addltionally used
according to the lnvention.
The K-value is a technical measure of the average degree of
polymerization of a polymer: -
K-value = 1000 k
2 0 Where:
k=t1.5 lg z - 1 + ~f1 ~ ~200/c + 2 + 1.5 lg z) 1.5 lg zl)/(150 + 3c)
z = ~/~;70; '7 = viscosity of the solution, ~7O = viscosity of the
solvent, c = concentration of the solution ln g/100 ml.
As acryllc reslns lnsoluble ln water, which are soluble or at least
swellable in an alkali, copolymers of methacrylic acid and at least one
alkyl methacrylate are suitable, with the alkyl methacrylate or at least
one of the alkyl methacrylates having an alkyl group containing 1 to 15
carbon atoms. Preferably, this binder is a copolymer of methacrylic
9~ 2 K-2506
acid and a Cl to C15 alkyl methacrylate, in particular of methacrylic
acid and methyl or ethyl methacrylate in weight ratios ranging between
10: 90 and 25: 75 (relative to the monomers used). Also preferred are
terpolymers of methacrylic acid and two different Cl to C alkyl
methacrylates, one of these being, in particular, methyl or ethyl
methacrylate. Especially advantageous are terpolymers of methacrylic
acid, methyl or ethyl methacrylate and a C4 to C8 alkyl methacrylate,
such as n-hexyl methacrylate, e.g., in weight ratios ranging between
16: 13: 71 and 26: 15: 59 , as described in German Offenlegungs-
schrift No. 2,064,080, or U. S. Patent No. 3,804,631.
Apart from the copolymers and terpolymers mentioned above, theacrylic resin which is soluble or at least swellable in an alkali may be
a terpolymer of (A) an unsaturated carboxylic acid, (B) a Cl to C20,
preferably a C4 to C12 alkyl methacrylate and (C) a further monomer
copolymerizable with (A) and (B), the corresponding homopolymer of which
has a glass transition temperature of at least 80 C. These copolymers
are known from German Offenlegungsschrift No . 2, 363, 806, or from
U.S. PatentNo. 3,930,865.
As the component (C) of this terpolymer the following compounds
are among others which are suitable:
Styrene or a substituted styrene, e.g., vinyl toluene, p-chloro-
styrene, a-chlorostyrene, a-methylstyrene, vinyl ethyl-benzene, o-
methoxystyrene and m-bromostyrene; vinyl naphthalene or a substituted
vinyl naphthalene; a vinyl heterocycle, such as N-vinyl carbazole,
vinyl pyridine, and vinyl oxazole; a vinyl cycloalkane, e.g., vinyl
cyclohexane, 3,5-dimethyl-vinyl cyclohexane, acrylamide, methacryl-
amide, N-alkyl acrylamide, acrylonitrile, methacrylonitrile, aryl
methacrylate, aralkyl methacrylate, etc.
K-25 06
A preferred embodiment of the copylng composltion according to the
invention contains a terpolymer in which the component (C) ls styrene,
p-chlorostyrene, vinyl toluene, vinyl cyclohexane, acrylamide, meth-
acrylamide, N-alkyl acrylamide, phenyl methacrylate, acrylonitrlle,
methacrylonitrile or benzyl methacrylate. Of these, styrene is particu-
larly preferred.
As unsaturated carboxylic aclds (A) methacrylic acid, acrylic
acid, crotonic acid, sorbic acid or maleic acid or ltaconic acid or their
monoesters are preferably used. Methacrylic acid is particularly
preferred.
Particularly preferred are terpolymers of (A), (B) and ~C) in the
weight ratios of 25: 67: 8 to 35: 53: 12.
It is further possible that the blnder copolymer contalns, apart
from t~he components (A), (B) and (C), another alkyl methacrylate which
is copolymerlzable with these components and which may contain in its
alkyl group a number of carbon atoms different from (B). As a matter of ~ -
fact, all of the components (A), (B), and (C) may be present by several
of their representatives.
Binders comprising four monomeric units are, e.g., preferred
when a fine adlustment of certain properties, such as adhesion of the
copying composition to newly developed alloys, is required.
C)f the acrylic resins mentioned, which are soluble or at least
swellable ln an alkali, the polymers with acld numbers ranging between
60 and 200 and molecu~lar weights ranglng between 20,000 and 50,000
are partlcularly suitable.
Suitable light-sensitive copdensed diazonium compounds are in
particular condensates of diazotized p-amino diarylamines with com-
K- 2506
pounds containing carbonyl groups, e.g., aldehydes, preferably form-
aldehyde, or with aldehyde donors, e.g. paraformaldehyde. These and
similar compounds are disclosed in German Patent No. 1,214,086, or
U. S. Patent No. 3,235,334 and in U. S. Patents Nos. 2,922,715 and
2,946,683. Particularly preferred are condensation products of diazo-
tized p-amino diphenylamine and paraformaldehyde, which are free from
metal salts, corresponding to German Patent No. 1,214,086, or U. S.
Patent No. 3,235,384. Further, the diazonium condensates described
in German Offenlegungsschriften Nos. 2,024,242; 2,024,244, and
2,041,395, are suitable. These condensationproducts comprise at
least one unit each of the general types A(-D) and B, which are inter-
connected by bivalent intermediate members derived from a carbonyl
compound capable of condensation.
As the components A(-D)n and B practically any compounds may
be used which are capable of reaction, by condensation, with active
carbonyl compounds, in an acld medlurn and which are not decomposed
by the conditions of the condensation reaction.
Where:
A is a radical of a compound containin~ at least two
isocyclic or heterocyclic aromatic rings and which,
in an acid medium, is in at least one position of its
molecule condensable with an active carbonyl com-
pound,
D is a diazonium salt group which is linked to an
aromatic carbon atom of A,
n is an integer between 1 and 10,
B is a radical of a compound free from diazo groups,
which is, in an acid medium, in at least one position
~` ~9~;22 K-2506
of its molecule eapable of condensation with an
active carbonyl compound, in particular a radical
of an aromatic amine, a phenol, a phenol ether,
an aromatic thioether, an aromatic hydrocarbon, an
aromatic heterocyclic compound or an organic acid
a mide .
The anion of the diazonium salt is preferably derived from an ali-
phatic monosulfonic acid having from 1 to 6 carbon atoms. Condensates
of a 3-alkoxy-diphenylamine-4-diazonium salt and a derivative of di-
lû phenyl ether, diphenyl sulfide, diphenyl methane or diphenyl are
equally preferred.
A great number of examples of dlazo condensates of these kinds
are given in German Offenlegungsschriften Nos . 2, 024, 242; 2, 024, 244;
and 2,041,395, already mentioned.
The preferred part-by-weight ranges of the individual components
of the eopying eomposltlon are approxlmately as follows:
0.2 to 1.5 parts by weight of a diazo condensate,
0.1 to 5.0 parts by weight of the aerylie resin, - :
0.5 to 4.0 parts by weight of the water-soluble
synthetie polymer and, if required,
0 .01 to 0.175 part by weight of a dye.
The added dyes preferably act as contrast agents. Blue dyes are
best suited which, together with the yellow diazonium condensate, im-
part a green color to the eopying layer. This eombination has the ad-
vantage that upon exposure a elear image contrast is obtained, whieh
substantially reduees or even eliminates the risk of a double exposure
in praetice .
Suitable dyes are compounds which are soluble in organic sol- ;~
vents, e.g., those belonging to the class of azo or triphenyl methane
~ ~7~Z K-2506
dyes . A preferred dye is a coupling product of 2 ,4-dinitro-6-chloro-
benzene diazonium salt with 2-methoxy-5-acetylamino-N-cyanoethyl-
N-hydroxyethyl aniline.
The negative-working copying materials are produced in known
manner. The coating solution composed of the components of the copy-
ing composition and a suitablè solvent or solvent mixture is applied by
casting, spraying, immersion, application with rollers etc., so as to
form a film on the intended carrier, which is subsequently dried.
The carrier materials used for the reversal plate are generally
zinc or aluminum or laminates of zinc and polyester. In order to obtain
long runs it is advantageous to use a metal carrier with improved adhe-
sion, e.g., mechanically, chemically or electrolytically roughened and
anodized aluminum with an aluminum oxide weight of at least 3 g/m2.
The process for the preparation of a planographic printlng form
using the copying material according to the invention is, in detail, as
fol.loWs:
The copying material is exposed in the actinic range under a posi-
tive original and is developed with a suitable developer.
Preferred developers are aqueous allcaline solutions, e.g., of
alkali phosphates, alkali silicates or alkali borates, to which small
quantities of miscible organic solvents may be added, if required. The
pH value of the solutions is preferably between 8 and 10. For special
compositions small additions of suitable anionic wetting agents, such
as sodium lauryl sulfate or ammonium alkyl sulfate, have proved suc-
cessful. It is also possible to use solely developer mixtures composed
of deionized-water and an organic solvent miscible wlth water, -with the
addition of small quantities of wetting agents, if required.
After thoroughly rinsing with water, the plate is completely dried
and, if necessary, the film edges or defective areas are corrected by
-- 10 --
~97~ 2 K-2506
means of a masking lacquer. In order to ensure long runs, the subse-
quently applied lacquer is preferably dried for 10 minutes at 50 to 60
C and, if necessary, the plate is treated with a protective ink. Then,
any surplus lacquer and ink are removed by brisk brushing under water
and subsequently the hardened portions of the copying layer are removed
by treating-with a stripper.
As strippers, aqueous alkaline solutions likewise may be used.
They differ from the corresponding developers in that they have higher
pH values.
Finally, the surface of the plate is acidified or made hydrophilic,
preferably using dilute phosphoric acid, and, if required, it is coated
or preserved with a protective ink. Then the plate is ready for printing.
If the above procedure is appropriately modified the copying com-
position according to the invention, among others, also may be used for
the preparation of a printing form on a multi-metal carrler, e.g. a tri-
metal carrier.
For this purpose, the presensitized planographic printing plate
comprising the copying composition according to the invention and a
multi-metal carrier, e.g., a chromium/copper/aluminum carrier, is ex-
posed under a positive original; the non-hardened image areas are re-
moved by treatment with a developer; the bared carrier surface is etched
with a chromium etching solution until the copper appears; the copper
surface is preferably activated by treatment with compounds producing
oleophilic properties and, finally, the image areas hardened by the light
are removed with an alkaline solution. Following treatment of the image-
wise modified carrier surface, preferably with dilute phosphoric acid,
the planographic printing plate is ready for printing.
Carriers composed of copper/aluminum or brass/chromium are gen-
erally used for bimetal plates, whereas for trimetal plates carriers of
-- 11 ~
1~ ~9~1ZZ K- 2 5 0 6
aluminum/copper/chromium or steel/copper/chromium are generally
used .
In addition, printed circuits may be prepared using the copying
composition according to the invention. In this case, processing is
carried out as is usual for the preparation of bimetal plates: Following
exposure under a negative original the material is developed and then
etched and stripped. Carriers used for the preparation of printed cir-
cuits may be laminates of copper and a moulding material of phenolic
resin, or copper and a glass fiber reinforced epoxy resin or copper and
a polyimide.
As compared to the conventional copying compositions and
negative-working planographic printing plates the copylng compositions
and plates according to the present invention as well as the method
suggested for their processing have the following advantages:
The copying layer may be developed wlthout residue by means of
aqueous solutions which contain only very small amounts of organic
compounds and which, in addition, are ecologically acceptable. As a
consequence, no deep etching of the carrier surface is required after
development the copying layer is not susceptible to finger marks, it is
extremely well suited for storing, and in the light-hardened conditlon
it may be stripped without residue using aqueous alkaline solutions.
In contrast to the stripping method at present employed in the
graphic trade, involving the use of potassium permanganate and H2O2
mixtures, this stripping method is to a higher degree ecologically accept-
able and is thus less problematic.
The copying composition and the copying material prepared with
this copying composition as-well as the method for processing this
material are further illustrated by the examples which follow. Unless
-- 12 --
97~ 2 K-2506
otherwlse stated, the percentages and quantities specified in the exam-
ples are by weight. The relation between parts hy weight and parts by
volume corresponds to that between g and ml.
Example 1
To an electrochemically roughened and anodized aluminum surface
wlth an oxide layer of 3 g/m2 a solut~on of the following composition is
applied:
1.34 parts of a terpolymer containin~ 62.5 per cent of
n-hexyl methacrylate, 12.5 per cent of methyl
methacrylate and 25 per cent of methacrylic
acid having an acid number of 155,
4 parts of a copolymer contalnlng 98 per cent of N-
vlnyl-N-methyl acetamide and 2 per cent of
2-ethyl-hexyl acrylate havlng a K-value
of 45 to 50, measured as a 1 per cent solution
ln methanol,
0.53 part of a polycondensate of p-diazodlphenylamine
and paraformaldehyde, as described in Example
1 of German Patent No. 1,214,086, or U. S.
Patent No. 3,235,384. (For this purpose,
approximately 42 parts of an 85 per cent phos-
phoric acid, 3.3 parts of paraformaldehyde and
23 parts of diphenylamine-4-dla~onium chloride
are stirred in at room temperature. The resulting
viscous solution ls stirred for 30 minutes at
room temperature, Subsequently, lt ls heated
to 4 0 C~ C durin~ 24 hours . )
:;
- 13 -
71~;~
K-25 06
0.04 part of a dye obtained by coupling 2,4-dlnitro-6-
chloro-benzene diazonlum salt wlth 2-methoxy-
5 -acetylamlno-N-cyanoethyl-N -hydroxyethyl-
anillne,
4.06 parts of methyl ethyl ketone, and
90 . 03 parts of ethylene glycol monomethyl ether.
The solution is applled by casting or whirler-coating in such a
manner that a dry layer weighing 2.8 to 3 g/m2 is obtained.
Subsequently, the platè is drled for 2 minutes at 100C. Follow-
ing an exposure of 35 seconds under a positive original with a Xenokop
(capacity 8 kW, distance 80 cm, model BIKOP of Messrs. ~limsch,
Neu-Isenburg) the exposed plate is developed for one minute, using a
plush pad, with a developer of the following composition:
3 parts of n-propanol,
0.05 part of sodium lauryl sulfate as a wetting agent; and
~96 . 95 parts of deionized water,
so that a negative image of the orl~inal ls obtained.
After thoroughly rlnslng with water, the plate is dried for 10 min-
utesat50C.
Subsequently, possible film edges or defective areas are correct-
ed, e.g., by means of "Abdeckfarbe-Rot" of Messrs. EGGEN-Hannover,
Followin~ drylng of the correcting agent, e.g., under a hot-air blower,
the plate is coated with a lacquer. Any commercially available lac-
quers may be used, such as "Ha~olac" of Messrs. Hauslelter (Munich),
"EGGEN-Stabil-Lack" of Messrs. EGGEN-Hannover, "Rubilac 9" of
Messrs. IMG ~Verona~ Italy) and "Krause-Alu-Emaille-Lack" of Messrs.
`~ Krause tBielefeld).
The lacquer ls dried for 10 minutes at 50 to 60 C in a drying
chamber. Then, various protective inks may be applled, such as
.
-- 14 --
971~;2
K-2506
"Schutzfarbe S" (EGGEN), "Haco-Pos. Fettfarbe" (Hausleiter) or "RC
43" (KALLE). Prior to stripping, any surplus lacquer and greasy ink are
removed by brushing in water.
The light-hardened stencil is then stripped using a solution of
the following composition:
9 parts of completely softened water,
5.3 parts of sodium metasilicate 9 H2O,
3.4 parts of tert. sodium phosphate 12 H2O, and
0.3 part of sec. sodium phosphate.
Subsequently, the plate is acidified-with a 1 per cent phosphoric
acid and then preserved.
On a (Multilith 1850) printing machine approximately 150,000
flawless prints without loss of tone vaLue were produced.
Example 2
A solution of:
1.78 parts of a terpolymer binder of styrene, n-hexyl
methacrylate and methacrylic acid in a ratio
of 10: 60: 30, having an acid number of 195
to 200,
3.56 parts of a copolymer as described in Example 1,
part of a diazonium mixed condensate of 1 mole of
3-methoxy-diphenylamine-4~diazonium sulfate
and 1 mole of 4,4'-bis-methoxy methyl-diphenyl-
ether, prepared in an 85 per cent phosphoric acld ~ ;~
and isolated as methane sulfonate,
0.1 part of the dye described in Example 1, in
94 parts of ethylene glycol monomethyl ether,
is applied to an electrochemically roughened and anodized aluminum
-- 15 --
7~'~Z
K-2506
plate wlth the aid of a casting device in such a manner that after drying
in a stream of warm air a layer weighing about 2.5 g/m2 is obtained.
Subsequently, the plate is exposed for approximately 30 seconds
under a positive original using a metal halide lamp with a capacity of
5 kW, positioned at a distance of 140 cm.
The image areas which are not cross-linked are washed out using
a plush pad with a developer of the following composition:
0.8 part of polyethylene glycol 200,
0.6 part of sodium lauryl sulfate, and
98.6 parts of deionized water.
After thoroughly rinsing with water, the plate is dried for 10 min-
utes at 50 C. The plate is further processed as described in Example
1, preferably using "Abdecklack-Rot" of Messrs. EGGEN as a masking
lacquer and "EGGEN-Kopierlack-Stabll" as a lacquer.
The light-hardened stencil is strlpped using the same solution as
in Example 1. Up to 150,000 copies are printed with these plates.
Example 3
A solution of:
4 parts of a terpolymer of n-hexyl methacrylate, methyl
methacrylate and methacrylic acid in a ratio of
; 62.5 :12.5 :25, having an acid number of about
160,
1 part of a copolymer as described in Example 1,
1 part of a polycondensate of p-diazo-diphenylamine
with paraformaldehyde, a s described in Exam-
ple 1,
0.075 part of the dye described in Example 1, in
15 parts of methyl ethyl ketone, and
70 parts of ethylene glycol monomethyl ether,
K-25 06
is whirler-coated on a trimetal plate composed of Fe/Cu/Cr in such a
manner that a layer weighing about 2 g/m is obtained. The plate is
dried for 2 minutes at 100 C.
Subsequently, the coated plate is exposed for 150 seconds under
a positive original using a Xenokop (capacity 8 kW, distance 80 cm,
model BIKOP of Messrs. Klimsch, Neu-Isenburg), and developed with
a developer of the following composition:
70 parts of completely softened water,
25 parts of n-propanol,
5 parts of MgSO4 7 H2O, and
0.5 part of lauryl polyglycol ether.
The plate is rinsed with water and dried with the aid of a fan.
The developed plate is then treated with a solution of:
17.4 per cent of calcium chloride, 35.3 per cent of zinc chloride,
2.1 per cent of hydrogen chloride and 45.2 per cent of water, until the
copper in the developed image areas is entirely bared. It is again
rinsed with water and the light-hardened stencil (etch resist) is re-
moved-wlth a stripper, as described in Example 2.
After rubbing the plate with a conventional activator, such a~
sulfuric acid or mercapto compounds, in order to render the copper ~ ^-
surface oleophilic, the plate is rinsed with-water and then a greasy
- ink is applied.
Example 4 '
~` A solution of:
part of a terpolymer of n-he~yl methacrylate,
methyl methacrylate and methacrylic acid
in a ratio of 62.5: 12.5: 25, having an
acid number of about 160,
- 17 ~
~7~2;2 K- 2 5 0 6
4 parts of a copolymer containing 91 per cent of
N-vinyl-N-methyl acetamide and 9 per cent
of 2-ethyl hexyl acrylate, having a K-value
of 70, measured as a 1 per cent solution in
methanol,
0.8 part of a polycondensate of p-diazo diphenylamine
with paraformaldehyde, according to Example 1,
0.175 part of the dye described in Example 1, in
3 .2 parts of methyl ethyl ketone, and
1090.83 parts of ethylene glycol monomethyl ether,
is appll0d to an electrochemically roughened and anodlzed aluminum
plate with an oxide layer of 10 g/m by castlng or whirler-coating in
such a manner that a layer weighing 2 .2 g/m2 is obtained.
The plate is then dried for 2 minutes at 100C. Following expo-
sure for about 30 seconds under a positlve original using the lamp de-
scribed in Example 2 positioned at a clistance of 140 cm, the unexposed
image areas are washed out with a 1 per cent phosphoric acid, and the
plate is rinsed with water.
The deve.loped plate is dried for 10 minutes at 50C, and is then
20further processed as described in Example 1. ~:
70,000 to 80,000 flawless prints are obtained.
Example 5
A solution of: -
1. 78 parts of a copo.lymer of methyl methacrylate/
methacrylic acid in a-weight ratio of 90: 10,
having an acid number of 65 and an average
molecular weight of 30, 000,
3.56 parts of a copolymer as described in Example 1,
'
18 -
. .
7~L~2Z K-2506
0.40 part of a polycondensate of p-diazo diphenylamine
and paraformaldehyde as described in Example 1,
0 . 04 part of the dye described in Example 1, in
60 parts of ethylene glycol monomethyl ether
is whirler-coated on an electrochemically roughened and anodized alumi-
num plate in such a manner that a layer weighing approximately 2 . 8
g/m2 is obtained . The plate is dried for two minutes at 100 C . Fol-
lowing an exposure of 45 seconds under a positive original by means of
a Xenokop (capacity 8 kW, distance 80 cm, model BIKOP of Messrs.
Klimsch, Neu-Isenburg) the exposed plate is developed during 45 sec-
onds, using a plush pad, with a developer composed of:
5 parts of n-propanol, and
95 parts of deionized water,
so that a negative image of the original is obtained.
The plate ls further processed as described in Example 1.
Example 6
A solution of the following composition:
1.34 parts of a copolymer of methyl methacrylate/
methacrylic acid in a weight ratio of 80: 20,
having an acid numberof 120 and an average
molecular weight of 3 5, 000,
4 parts of a copolymer as described in Example 1,
0.5 part of a polycondensate of p-diazo diphenylamine
and paraformaldehyde as described in Example 1,
0 . 04 part oi the dye described in Example 1, in
65 parts of ethylene glycol monomethyl ether,
is applied to an electrochemically roughened and anodized aluminum
plate in such a manner tha~ a layer weighing approximately 3 g/m2 is
obtained .
-- 19 --
~9~2 ~-2506
The plate is further processed as described in Example 1. The
exposed plate is treated with the following developing solution:
3 parts of n-propanol,
0.06 part of sodium lauryl sulfate
0. 01 part of antifoaming solution T (see Karsten Lack-
rohstofftabellen, 5th Edition, page 415).
The plate is further processed as described in Example 1.
Approximately 100,000 prints are obtained.
Example 7
A plate of a coppe~phenoplast laminate cleaned with pumice ;~
powder and thoroughly rinsed with water is first dried with a blower
and then dried for 10 minutes at 100C.
Subsequently, the plate 1s whirler-coated with a solution of:
4.25 parts of a terpolymer of n-hexyl methacrylate,
methyl methecrylate and methacrylic acid
in a ratio of 62.5 :12.5 :25, havlng an
acid number of about 160,
0.75 part of a copolymer as described in Example 1,
0.4 part of a polycondensate of p-diazodiphenylamine
and paraiormaldehyde, as described in
Example 1,
0.04 part of the dye as described in Example 1, in
60 parts of ethylene glycol monomethyl ether,
in such a manner that a layer weighing approximatély 4 g/m2 is
obtained .
The layer is pre-dried for 1 minute in warm air, and the plate is
then placed for 2 minutes in a drying chamber at a temperature of 100
C.
- 20 -
.; .,., . - ., . '
~1~97~ K--2506
Following an exposure of 60 seconds under a negative original
using a Xenokop (capacity 8 kW, distance 80 cm, model BIKOP) the
unexposed image areas are removed with a developer of the following
composition:
220 parts of deionized water,
35 parts of n-propanol,
6.5 parts of MgSO4 7H2O, and
0 . 7 part of lauryl polyglycol ether.
After thoroughly rinsing with water the layer is sub~ected to a
compressed air stream, and subsequently the bared copper is etched
in an etching machine using a ferric chloride solution of 42 Be, with
the hardened image areas serving as an etch resist.
Following stripping of the cross-linked layer areas with acetone
the desired cLrcuit path image is obtained.
It will be obvLous to those skllled in the art that many modifica-
tions may be made within the scope of the present invention without
departing from the spirit thereof, and the invention includes all such
modifications .
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