U.S. patent number 3,839,038 [Application Number 05/408,142] was granted by the patent office on 1974-10-01 for photosensitive silver halide layers and process.
This patent grant is currently assigned to Itek Corporation. Invention is credited to Robert F. Gracia, Richard A. Laughrey, Paul F. Tuohey.
United States Patent |
3,839,038 |
Gracia , et al. |
* October 1, 1974 |
PHOTOSENSITIVE SILVER HALIDE LAYERS AND PROCESS
Abstract
This disclosure concerns a process of producing photographic
images by photoexposing a photosensitive silver halide layer of
less than two microns thickness and subsequently physically
developing the exposed layer to obtain a visible image. The
preferred silver halide layers are of a thickness of less than one
micron. The resulting photo-images are characterized by extremely
high resolution, especially resolution required for holographic
imaging and reproduction. Additionally, the images are adherently
bonded to the film substrate. There is a need for silver halide
layers which give high order resolution, for example as required in
holography. Additionally, particularly in the production of
photographic film, printing plates, nameplates and electrical
printed circuits and components, there is need for silver halide
layers which yield metal images that are adherently bonded to the
layer substrates. The present invention provides a solution to the
said needs and additionally provides this solution by way of
extremely rapid and facile processing chemistry.
Inventors: |
Gracia; Robert F. (Scituate,
MA), Laughrey; Richard A. (Woburn, MA), Tuohey; Paul
F. (Quincy, MA) |
Assignee: |
Itek Corporation (Lexington,
MA)
|
[*] Notice: |
The portion of the term of this patent
subsequent to November 27, 1990 has been disclaimed. |
Family
ID: |
26723357 |
Appl.
No.: |
05/408,142 |
Filed: |
October 19, 1973 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
45927 |
Jun 12, 1970 |
3775114 |
|
|
|
Current U.S.
Class: |
430/315; 430/298;
430/496; 430/526; 430/275.1; 430/416 |
Current CPC
Class: |
G03C
5/58 (20130101); G03C 1/04 (20130101); G03C
1/62 (20130101) |
Current International
Class: |
G03C
5/58 (20060101); G03C 1/04 (20060101); G03C
1/62 (20060101); G03C 1/52 (20060101); G03c
005/00 () |
Field of
Search: |
;96/36.2,48PD,86R,27R,5R,33 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Smith; Ronald H.
Assistant Examiner: Kimlin; Edward C.
Attorney, Agent or Firm: Blair; Homer O. Nathans; Robert L.
Goodson; W. Gary
Parent Case Text
This is a division of application Ser. No. 45,927, filed 6-12-70,
now U.S. Pat. No. 3,775,114.
Claims
1. A process for producing a printed circuit of an electrically
conducting metal image comprising the steps of exposing an imaging
medium comprising a photosensitive silver halide layer of less than
about 2 microns thickness on a support and contacting the imaging
medium to image forming materials comprising a solution of metal
ions to thereby form electrically
2. Process as in claim 1 wherein the silver halide layer is of a
thickness
3. Process as in claim 1 wherein the thickness of the silver halide
layer
4. Process as in claim 3 wherein the amount of silver, as silver
halide, is
5. A process of producing a printed circuit of an electrically
conducting coherent metal image adherently bonded to a support
which comprises:
1. forming catalytic nuclei which will cause the reduction and
deposition of metal from a physical developer by a process
including the step of exposure of an imaging medium comprising a
photosensitive silver halide layer of less than about 2 microns
thickness on a support; and
2. thereafter depositing sufficient metal on the catalytic nuclei
portions of the imaging medium to form said electrically conducting
coherent metal
7. Process as in claim 6 wherein said photosensitive silver halide
layer
8. Process as in claim 6 wherein the catalytic nuclei image formed
by exposure of the photosensitive silver halide layer is contacted
with a chemical developer to develop a silver image followed by
contact with a physical developer comprising a solution of
reducible metal ions and a
9. Process as in claim 6 wherein the depositing of metal is
conducted by first contacting with an electroless metal plating
bath comprising a solution of metal ions followed by contacting
with an electrolytic copper plating bath to produce a conductive
copper image having a thickness from
10. Process as in claim 6 wherein the photosensitive layer has a
thickness of less than about 0.5 micron and wherein the metal
deposited in step (2)
11. Process as in claim 6 wherein the metal is deposited by
contacting the imaging medium with image froming materials which
comprise ions of a metal
12. Process as in claim 11 wherein the metal is silver end the
reducing
13. Process as in claim 6 wherein the metal is deposited by
contacting the imaging medium with image forming materials which
comprise ions of a metal
14. Process as in claim 6 wherein the average silver halide
particle size
15. Process as in claim 6 wherein the metal support comprises
aluminum.
17. Process as in claim 16 wherein the aluminum is anodized.
Description
DESCRIPTION OF THE INVENTION
This invention relates to the production of photographic metal
images by physical development of very thin light-sensitive silver
halide layers of thicknesses of less than about 2 microns and
preferably less than about 1 micron. The silver halide is
preferably dispersed in a binder. Additionally, the invention
provides a new process for producing the very thin, light-sensitive
layers for use in producing photographic metal images by physical
development, as well as the products produced thereby.
The very thin, light-sensitive silver halide layers are produced by
coating a low solids emulsion preferably containing less than 10
percent and more preferably less than 5 percent total solids on a
suitable substrate to obtain very thin silver halide layers, the
amount of the silver halide preferably being from about 100 and
more preferably from about 10 to about 20 grams/per liter of the
emulsion. It is necessary only to have sufficient silver halide
present to obtain a latent image upon exposure which is amplifiable
by physical development, preferably to produce good image adhesion
to the support. The coating emulsion is made up using conventional
binders, such as gelatin, polyvinyl alcohol and the like, with the
selected silver halide, the ratio of silver halide to binder being
from as high as 20/1 to as low as 1/20 but preferably, for best
results, from about 3/1 to about 1/3. Slow, fast, or intermediate
photographic response silver halide layers can be formed by control
of the particle size as is generally known and well documented in
the literature. The silver halide emulsion can be
stoichiometrically balanced or contain excess of either silver ions
or halide ions depending on the end use or the shelf-life
requirements, as is also well known. For example, for slow
photographic response, large excesses of halide in the emulsion are
avoided since these favor larger silver halide particle size
through ripening and, as is well known, the larger particles lead
to fast photographic response.
The production of photographic metal images is accomplished by
contacting the very thin, light-sensitive layer after photoexposure
with a physical developer. As is generally well-known, a physical
developer is composed of a reducible metal ion and a reducing agent
therefor. In physical development, the reducible metal ion, after
reduction, forms the greater part of the developed photographic
image, rather than the silver halide of the photosensitive
emulsion, although the resulting image does contain at least
light-reduced silver particles and may contain additional silver
depending on the reducing system employed. In other words, the
silver halide of the photosensitive layer hardly contributes to the
final visible image. Such physical development is distinguished
from the usual chemical development associated with silver halide
photoprocessing which is predicated on the formation of visible
images solely utilizing the silver of the silver halide in the
photosensitive layer. Classically, the silver halide in the
photosensitive layer is solubilized using complexing agents such as
soluble thiosulfates or thiocyanates and the image is formed by
reduction of the solubilized silver halide using conventional
reducing agents, i.e., developers.
The use of very thin, light-sensitive silver halide layers provides
substantial advantage in many areas of photographic production of
visible images. The said layers permit ready and facile physical
development to produce very desirable properties in the metal
images obtained. For example, the metal images are readily produced
in a form very desirable for printed circuit and planographic
master production, i.e. the image obtained can be more readily
produced as a lustrous continuous and conductive metal image than
can be obtained with thicker photosensitive layers. Further, with
the aforesaid very thin photosensitive layers, after physical
development, the image produced is more adherently bonded to the
substrate when compared to images produced with layers of 2 microns
or higher thickness. This is of particular advantage when the
substrate is metal plate. In producing printing plates, a strongly
adherent continuous lustrous metal image is more readily obtained
then with thicker photosensitive layers. The thin, light-sensitive
silver halide layers of this invention also give rise, on
development, to exceptionally thin metal images which are
especially suitable where distortion due to layer thickness or
metal image thickness is to be avoided as in photogrammetry, as in
production and reproduction of holographic images where high
resolution is an absolute requirement. The present new thin layers
give images which are of exceptionally high resolution.
The use of such thin photosensitive layers as in the present
invention also leads to considerable advantage in the packaging of
film where, conveniently, the film is usually packed in rolls, with
the present film requiring less space than prior art films designed
for the same use. Thus, in the same package space, more of the
present film can be made available than with conventional film.
Additionally, the fixing and drying time is significantly improved.
This is especially important, for example, in the high speed
processing of photographic film (e.g., at speeds of 100 feet/min.
or greater). An additional advantage is that the manufacture of the
film is simplified since the photosensitive layer drys and sets
more readily and has less rheology problems than with film having
thicker layers. The film can be more economically manufactured
since conventional coating equipment can be used such as film
subbing equipment rather than the relatively slow and more costly
photographic coating equipment.
One of the more important advantages of the photosensitive medium
of this invention is that it has the capability of being very high
photographic speed such as for taking pictures in a camera and also
capable producing extremely high resolution and at the same time
having the capability of high or low gamma images. This unusual
combination of properties makes possible improved high resolution
original aerial photographs, forming a printing plate by exposing
directly onto a photosensitive plate from a computer-driven CRT or
other exposure device. Photographic film having improved archival
quality is also possible due to the excellent adhesion possible
between the image and the support. Thus, abrasion which might
remove the binder does not necessarily remove the image from the
film.
PREFERRED EMBODIMENTS OF THE INVENTION
The silver halide employed is that which is conventionally used in
photography and is made in the conventional way, i.e., by reaction
in aqueous systems of soluble silver salt such as silver nitrate or
sulfate and a soluble alkali metal halide, such as sodium chloride,
sodium bromide or sodium iodide, or corresponding potassium salts.
The formation of the particles of silver halide can be controlled
to permit any desired particle size, ranging from as little as 30
to 50 Angstrom units up to conventional particle size. Preferred
methods are those which encourage fine particle size, usually less
the 0.5 microns. For general convenience, such fine particle size
is obtained by using systems of low solids content, preferably at
approximately 5 percent total solids (including the weight of
silver halide and the binding agent) and rapidly mixing the soluble
alkali metal halide solution with the soluble silver salt solution,
usually at about room temperature, for convenience.
The binder employed can be any of those conventionally used in
forming silver halide emulsions. Preferably, the binder should be
wettable by aqueous solutions to a sufficient degree to permit
rapid processing of the exposed layer. Preferred binders are the
usual gelatin, so common in silver halide films, polyvinyl alcohol,
polyacrylates, including polyacrylic acids, casein and the like.
The use of polyvinyl alcohol is especially preferred where fine
particle size of the silver halide is desired since the binder
apparently discourages ripening, i.e., growth of the silver halide
particles which occurs on standing.
The binder, of course, is added to the aqueous system used to form
the silver halide particles, as a matter of convenience. In
addition, other materials can be added to the binder-aqueous system
as desired to obtain specific effects in the photosensitive layer
during or after exposure. For example, sensitizing dyes, thiourea,
toners, mercuric salts or the like can be added for their known
photographic effects, e.g., thiourea to assist in formation of
black photographic images, and the sensitizing dyes to alter the
spectral response of the layer on photoexposure.
After preparation, the emulsion is then coated on a substrate. The
coating process can be any of those commonly employed, e.g., air
knife, roller coating or similar such coating means. With proper
settings, a coating weight of about 0.5 grams per square meter can
be readily attained and gives a uniform layer of about 0.5 microns.
By adjustement, thinner layers, e.g. 0.2 - 0.3 microns and even
lower, can be made. Thicker layers up to one micron and higher
present no problem to those skilled in the art. The optimum layers
are produced with a ratio of silver halide to binder of from about
3/1 to about 1/3.
The preferred thin layers, i.e., of thickness below one micron,
usually contain as silver halide, approximately 0.3 grams of silver
per square meter.
The physical developers which are preferred are so-called
stabilized physical developers, particularly those which are most
effective at acid pH value, i.e., below pH 7. Especially preferred
are the so-called mono-bath physical developers which are
stabilized. Monobath physical developers consist of a single
solution of reducible metal ion and the reducing agent therefor. On
prolonged use, there is apparently a tendency to formation of
undesired side products. Stabilized monobath physical developers
are known in the art and usually include surfactants or similar
such materials which prolong the life of the physical developer.
One of the basic problems with physical developers is the tendency
toward decomposition with formation of insoluble materials that
contaminate photographic emulsions or otherwise are undesirable in
terms of their adverse affect on the acceptability and/or
aesthetics of the photographic image. The surfactants apparently
minimize such decomposition, i.e., stabilize the physical
developer.
The optimum results attainable with the physical developers is at
pH values below 7, i.e., in acid media, usually at about pH 1-5.
Higher pH values should be avoided because of the possible adverse
effect on the surfactants which are sensitive to high pH
values.
In the physical developers employed, the reducible metal ion is
usually of a metal at least as noble as copper, e.g., silver,
copper, gold, platinum, palladium and the like. However, other
metal ions such as nickel and tin can also be used, with
appropriate reducing agents. Reducing agents for copper, silver and
like noble metal ions are readily determinable and are fully
described in the literature.
A particularly effective monobath physical developer is composed of
silver ion and, as reducing agent therefor, the ferrous-ferric ions
developer which is well-known to the art.
For best results, the monobath physical developers are usually
prepared immediately before use to increase the useful life of the
system. The surfactants are added during fromation of the monobath
to obtain maximum stabilization.
The physical developers may contain additional materials which
assist in formation of the desired type of photographic image.
Thus, for example, complexing agents for the metal ion to be
reduced may be present, or toners which affect the physical
appearance of the resulting photographic image.
In lieu of the described monobath physical developers, there may be
used separate solutions of the reducible metal ion and the selected
reducing agent. For example, the physical developer can be made up
of separate solutions of silver ions, and Metol. The exposed layer
is first immersed in the silver ion solution and subsequently in
the Metol solution. The results obtained are quite acceptable but
the separate steps are undesirable for obvious reasons of time and
labour waste. Additionally, the results are not always as reliable
with reference to the reproducibility, desirable photographic image
characteristics as those attainable with monobath physical
developers, especially in stabilized form.
One or both of the oxidizing and reducing agent components of the
developer may be present in the photosensitive medium prior to
exposure, if desired.
The physical developer, irrespective of monobath, separate
solutions or stabilization, can be applied to the photosensitive
layers in the from of viscous solutions or gels with essentially
the same results as the liquid systems. The efficiency of viscous
solutions, and particularly gels, make these forms of the physical
developer particularly desirable in commercial use of the present
new thin photosensitive layers.
Alternately, the image forming materials (physical developer) may
be incorporated in the photosensitive layer of this invention.
Thus, a decomposable metal salt such as silver EDTA may be
incorporated in the photosensitive layer as described in copending
U.S. application Ser. No. 45,909, filed June 12, 1970 in the name
of John Manhardt, entitled "Print-out Processes and Imaging Media
Therefor," now Pat. No. 3,794,496. Also, an oxidizing agent and a
reducing agent such as described in U.S. Reissue Pat. No. Re.
26,719 may be utilized as the image forming materials in the
photosensitive medium. The advantages of a high resolution
print-out photographic system requiring no wet processing are
apparent.
The sensitometry of the present thin films can be altered to meet a
desired photographic use. For example, the photoresponse and gamma
can be changed in the emulsion if different mixtures of silver
halides are used, and/or by increasing the silver halide particle
by allowing ripening to take place. Gamma can be controlled by
addition of known materials, e.g., cadmium salts, or by regulating
the amounts of surfactants and/or pH of the physical developer.
In a particularly preferred form of the invention, the exposed thin
layer is first chemically developed, e.g., by contact with known
chemical developers such as hydroquinone, metol, and the like,
after which physical development, as hereinbefore described, is
used to obtain the final image. Such chemical development usually
leads to a faint silver image which is then amplified by physical
development. The intermediate chemical development, followed by
physical development, results in an increase in the effective
speed. The higher effective speed is accompanied by a slight
decrease in gamma. The intermediate chemical development is
particularly desirable to obtain continuous tone images in the
physically developed film. In addition, when the metal ions of the
physical developer are other than silver ions, the intermediate
chemical developement step gives substantially better results in
the physical development step.
The intermediate chemical development of the exposed thin silver
halide layer leads to a more adherent metal image obtained by
physical development. This adherence of the metal image is, of
course, in reference to the substrate, and, in photographic media
comprising a metal substrate, this improved adherence to the metal
substrate is especially desirable, particularly in making printing
plates, nameplates, electrical circuits, and the like.
In another preferred form of the invention, the thin,
photosensitive layer is applied to a hydrophobic substrate such as
cellulose acetate or a polyester film base, e.g., polyethylene
terephthlate, without the use of the subbing layer or with a single
subbing layer rather than the two or more which is so common to
such substrates. Furthermore, the coatings can be applied with
conventional coating equipment such as equipment for applying
subbing layers rather than expensive and slow photographic coating
equipment. The applied silver halide layer is comprised of a binder
principally consisting of material normally designated "subbing
binder," or subbing material which preferably comprises a mixture
of a hydrophobic and hydrophilic material such as a mixture of
gelatin and a synthetic polymer. The "subbing binder" or subbing
material may also comprise solely a synthetic hydrophilic binder
material capable of adhering to the polyester or cellulose
triacetate support or such a support having a single subbing
layer.
The subbing material is a material which will allow development to
take place in. Emulsion polymers or combinations of these polymers
with gelatin are preferred. Examples of such subbing materials are
vinylidene chloride copolymers, acrylate polymers and copolymers
polyvinyl acetal polymers, and polybutadiene copolymers. Suitable
such copolymers include the vinylidene chloride copolymers
containing at least 35 percent by weight of vinylidene chloride,
e.g., the poly(vinylidene chlrodie and acrylic or methacrylic ester
or nitrile and itaconic acid) compounds described in Alles and
Saner U.S. Pat. No. 2,627,088, the polyisocyanates and
polyisothiocyanates described in Saner U.S. Pat. No. 2,698,242, the
mixtures of (a) polyester of ethylene glycol, terephthalic acid and
polyethylene glycol or saturated aliphatic dicarboxylic acid,
soluble in CHCl--CCl.sub.2, and (b) organic polyisocyanate or
polyisothiocyanate described in Saner U.S. Pat. No. 2,698,241 and
the polyesters of aforesaid item (a) described in Alles and Saner
U.S. Pat. No. 2,698,239. The various copolymers of vinylidene
chloride mentioned are described in U.S. Pat. No. 2,627,088,
including methods of preparation, and the said patent is
incorporated hereby by reference for the said disclosure.
Additional subbing materials are the butadiene copolymers as
described in Belgium Pat. No. 721,469.
An especially preferred embodiment is a sheet material wherein the
binder additionally comprises gelatin.
The following examples further illustrate the invention. Unless
otherwise indicated, all parts are parts by weight.
Example 1
A 5 percent solution of polyvinyl alcohol (PVOH) is prepared by
slowly adding the resin powder to distilled water at room
temperature with rapid stirring. The temperature is slowly raised
to 95.degree. C. while maintaining rapid agitation, and held at
95.degree. C. for about 0.5 hour.
The following solutions are prepared using the 5 precent PVOH
solution thus prepared:
Solution A Solution B ______________________________________
Distilled H.sub.2 O 84.0 Distilled H.sub.2 O 84.0 10% aq. NaCl 30.9
10% aq. AgNO.sub.3 81.5 5% PVOH 14.0 5% PVOH 14.0
______________________________________
(solution B is not prepared until immediately before the described
use, i.e. freshly prepared before mixing with Solution A.)
Solution A is added to Solution B under good agitation within about
5 seconds total addition time, at room temperature. The mixture is
then sonified (Bronson Sonifier) for 4 minutes at about 100 watts.
Then, 248 parts of 5 percent PVOH solution is added to the mixture
under good agitation and agitation is continued for about 5 minutes
thereafter. Subsequently, the mixture is filtered through a 5
micron bag to obtain an emulsion of the following
characteristics:
Emulsion Constants:
1:2 rates of silver chloride to PVOH
10 percent excess chloride
4.5 percent total solids
12.4 g. silver chloride/liter
pH = 5.9 to 6.2
viscosity = 6 to 8 cps
The emulsion can then be coated on a substrate by either air knife,
roller coating or similar coating means. Good results are obtained
using a roller coater with hard rubber rolls. With proper settings,
a coating weight of 0.5 g./m.sup.2 can readily be obtained.
A polyester film having a single vinylidene chloride copolymer
subbing layer is so coated and thoroughly dired by heating at about
27.degree.C for 10 minutes. The coated film is then exposed and
developed in the following stabilized physical developer:
Solution I Ferrous Ammonium Sulfate 78.4 gms. bring to 1 Ferric
Nitrate 32.3 gms. liter with Citric Acid 80.0 gms. distilled water
Solution II Distilled Water 100.0 gms. Synthrapol N 1.0 gms. Armac
12D 1.0 gms. Developer Solution I 125.0 gms Solution II 25.0 gms 3N
Silver Nitrate 6.0 gms.
A lustrous, coherent, metallic image is obtained on the film.
Example 2
The following solutions are prepared as in Example 1:
Solutions
__________________________________________________________________________
A B C
__________________________________________________________________________
Distilled Water 92.0 Distilled Water 92.0 30% Phenyl Mercuric 10%
NaCl 30.9 10% AgNO.sub.3 81.5 Acetate 1.15 5% Lemol 16-98 206.0 5%
Lemol 16-98 206.0
__________________________________________________________________________
The solutions are mixed in the following order: Solution A is added
to Solution B, Soluction C is added to the mixture, and the mixture
is stirred and filtered as in Example 1, to obtain and emulsion of
the following characteristics:
Emulsion Constants
1.3 Silver Chloride to Binder
10 percent Excess Chloride
4.5 percent Total Solids
9.7 Grams Silver Chloride per Liter
1 percent Mercury on Binder Solids
pH = 7.7 to 8.0
Viscosity = 6 to 8 cps.
The combined solutions are used to coat a subbed, polycoated paper
stock with a roller coated and the paper then is exposed and
developed as in Example 1. The silver chloride particle size
(average) ranges from 50 to 200 A. and the layer thickness is about
0.1 micron.
Example 3
An emulsion containing 8 percent excess silver at a total solids
content of 4.4 percent is prepared from the following solutions:
Solution I Solution II ______________________________________ 18
cc. 3N AgNO.sub.3 3 gms. NaCl 210 cc. H.sub.2 O 210 cc. H.sub.2 O
72 gms. Lemol 16-98 (10%) 72 gms. Lemol 16-98
______________________________________
Solution II is added to Solution I rapidly with stirring and the
mixture is then sonified for 5 minutes. The emulsion is then used
to coat any desired substratefilm, paper, aluminum metal -- at a
coating weight of about 0.5 g/m.sup.2, i.e. at a thickness of 1
micron or less.
The coated substrate is then exposed and process as in Example
I.
Example 4
The following solutions are prepared:
Solution A ______________________________________ Distilled H.sub.2
O 85 ml. -Sodium Chloride 6.67 gms. Solution B
______________________________________ Distilled H.sub.2 O 250 ml.
-Silver Nitrate 15 gms. K&K Inert Gelatin 20 gms. Formaldehyde
1 gm. (3%)
Solution A is poured into Solution B at 60.degree. C. and
vigorously stirred for 3 minutes. After cooling to 30.degree.C. the
mixture is coagulated by rapid addition of methanol and distilled
water 1:1 cooled to -12.degree.C. The mixture is stirred until
coagulum forms and the liquid clears. The coagulum is removed and
cut into small "noodles" which are washed twice with cold distilled
water. The coagulum is then dissolved in water to form one liter
aqueous emulsion which is then used to coat substrates as in the
previous examples.
Example 5
The procedure of Example 2 is repeated with the added step of
chemical development prior to the physical development. The
chemical development is by immersion in a standard silver halide
developer, e.g. Kodak D-19 or D-76, to obtain a faint silver
image.
After physical development, the resulting image is more detailed
than that of Example 2, i.e. lower gamma.
Example 6
The procedure of Example 5 is repeated substituting a metal
substrate for the paper substrate and utilizing the following
physical developer:
CuSO.sub.4 (10% aq.)
Na.sub.4 EDTA (10% aq.)
NaCl
The resulting image is adherently bonded to the substrate.
Example 7
The procedure of Example 1 is repeated with the added step of
chemical development as in Example 5, i.e., prior to physical
development, and the resulting is of greater detail than that
obtained in Example 1. The photographic gamma is about 1.5 whereas
that of the Example 1 image is greater than 3.
Example 8
The procedure of Example 1 is repeated with the ex exception that
the physical developer is the following solution:
CuSO.sub.4
Ascorbic Acid
Example 9
The procedure of Example 1 is repeated with the exception that the
physical developer is the following solution:
AgNO.sub.3
Metol
Citric Acid
Comparable results are obtained.
Example 10
The procedure of Example 1 is repeated to form a printed electrical
circuit consisting of silver.
The printed circuit is then amplified to an additional thickness of
1-5 mils. by electrolytic deposition of copper using a conventional
copperizing bath, e.g. CuSO.sub.4 H.sub.2 SO.sub.4 solution at
coating electrical current.
The metal printed circuit is adherently bonded to the
substrate.
Example 11
The procedure of Example 2 is repeated using a brush-grained
anodized aluminum sheet as substrate in lieu of paper.
The resulting plate is then wiped with a dispersion of
mercaptobenzothiazole (e.g.) phosphoric acid (5 ml. 85 percent) and
dodecylammonium chloride (0.5 g.) in one liter of water. The silver
image will now accept lacquer or ink depending on whether it is to
be used as a color image (by inclusion of color in the lacquer) or
as a printing plate.
The metal image is adherently bonded to the aluminum substrate.
EXAMPLE 12
In a reaction flask equipped with a stirrer, a nitrogen inlet, a
dropping funnel, and a condenser are placed 10 liters of water and
2.88 liters of a 10 percent aqueous solution of the sodium salt of
sulphonated dodecyl benzene. Then the reaction flask is rinsed with
nitrogen and the liquid is heated to 60.degree.C. In another flask
are placed successively 800 ccs of isopropanol, 144 g of
N-vinyl-pyrrolidone, 108 g of n-butyl acrylate, 830 g of
N-tert.-butylacrylamide and 2,520 g of vinylidene chloride. The
mixture is sitrred and brought to dissolution by gentle
heating.
Through the dropping funnel a solution is added of 21.6 g of
ammonium persulphate in 400 ccs of water. Immediately pumping of
the monomer solution into the reaction flask is started. The rate
of pumping is such that after 75 min. all the monomer solution is
pumped over. Together with the monomer solution a further amount of
ammonium persulphate solution is added dropwise (64.8 g in 1,200
ccs of water). During the whole reaction period the temperature of
the mixture is maintained at 60.degree.C while refluxing. After all
the monomer has been added, again an amount of 21.6 g of ammonium
persulphate dissolved in 400 ccs of water is added at once. After
refluxing, stirring is continued for another 30 min. at
60.degree.C, whereupon the reaction mixture is cooled to room
temperature.
In order to precipitate the copolymer of vinylidene chloride,
N-tert.-butylacrylamide, n-butyl acrylate, and N-vinyl-pyrrolidone
(70:23:3:4), the latex formed is poured into a mixture of 40 liters
of 10 percent aqueous sodium chloride solution and 40 liters of
methanol while stirring. The fine grainy precipitate which is
obtained is repeatedly washed with water and finally dried.
An amount of 2.5 g of the vinylidene chloride copolymer formed
above are dissolved in a mixture of 90 ccs of butanone and 10 ccs
of nitroethane. The solution obtained is warmed to 25.degree. C and
coated on a plate of polymethyl methacrylate in such a way that
0.75 to 1.0 g of copolymer is present per sq.m. This layer is dried
at room temperature.
______________________________________ A copolymer latex is
prepared as follows: ______________________________________ In a 20
liters autoclave are placed successively: - water boiled under
nitrogen 10.2 l 10% aqueous solution of oleylmethyl- tauride 0.6 l
10% aqueous solution of the sodium salt of
heptadecyl-disulphobenzimi- dazole 0.6 l azodiisobutyronitrile 6 g
methyl methacrylate 1500 g butadiene 1500 g
______________________________________
After sealing of the autoclave, the strongly stirred emulsion is
polymerized for 6 hr. at 60.degree.C. This polymerization is
slightly exothermic for a short while. Then the pressure drops
rapidly. The polymerization is finished under reduced pressure. The
latex of the copolymer of butadiene and methyl methacrylate (50:50)
is then freed from residual traces of monomer by blowing at
60.degree.C and under a slight vacuum an air current above the
latex. Then the latex is cooled and filtered.
The above latex copolymer is now used to prepare an emulsion of the
following composition:
Solution A Solution B ______________________________________
Distilled H.sub.2 O 84.0 Distilled H.sub.2 O 84.0 10% aq. NaCl 30.9
10% aq. AgNO.sub.3 81.5 5% gelatin 14.0 5% gelatin 14.0
______________________________________
Solution A is added to Solution B with good agitation over a time
period of approximately 5 to 10 seconds. Then, 248 parts of a 5
percent latex copolymer prepared above is added to the mixture
under good agitation. The agitation is continued for 30 minutes.
The emulsion is then filtered and is ready for coating. The coating
may be applied by an air knife, roller coating or other means. The
coat weight should be kept at approximately 0.5 grams per square
meter or below.
The subbed polyester film having a single vinyl copolymer subbing
layer is so coated and thoroughly dried. The coat of the film is
then exposed and developed as described in Example 1.
Example 13
An emulsion is prepared as described above in Example 12 except
that the latex emulsion polymer used is either AC-22 or AC-33 as
obtained from Rohm & Haas. The emulsion is coated to an
identical coat weight and manner as in Example 12 and is exposed
and processed as described in Example 1.
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