U.S. patent number 3,649,336 [Application Number 04/763,382] was granted by the patent office on 1972-03-14 for plural coated sheet material.
This patent grant is currently assigned to Gevaert-Agfa N.V.. Invention is credited to Jan Jozef Priem, Lucien Janbaptist Van Gossum, August Jean Van Paesschen.
United States Patent |
3,649,336 |
Van Paesschen , et
al. |
March 14, 1972 |
PLURAL COATED SHEET MATERIAL
Abstract
Improved adherence is obtained for sheet material having a
hydrophobic film support or base, such as a hydrophobic cellulose
ester or polyester, by the combination of a vinyl polymer subbing
layer arranged directly on the hydrophobic support, the subbing
layer being formed of a copolymer containing at least 45 percent by
weight of vinylidene chloride and/or vinyl chloride monomer along
with a minor amount of a hydrophilic vinyl monomer with the balance
being constituted by any other vinyl monomer, and superimposed upon
the vinyl subbing layer a layer containing a mixture of gelatin
with a copolymer of butadiene and a vinyl monomer containing 30-70
percent by weight of butadiene, the ratio of the gelatin to the
butadiene copolymer being in the range of 1:3 to 2:1 by weight. An
additional layer can be applied over the gelatin/copolymer layer
and constituted by such ingredients as are desirable for the
particular utility of the resultant sheet material, such as
light-sensitive silver halide emulsion photographic layers,
electrophotographic layers containing finely divided
photoconductive material such as zinc oxide or some other
photosensitive semiconductive material, matte layers containing
pigment, diffusion transfer layers containing development nuclei
and so on. Alternatively, the ingredients appropriate to some
particular ultimate utility can be incorporated into the
gelatin/butadiene copolymer layer directly.
Inventors: |
Van Paesschen; August Jean
(Antwerpen, BE), Van Gossum; Lucien Janbaptist
(Kontich, BE), Priem; Jan Jozef (Berchen,
BE) |
Assignee: |
Gevaert-Agfa N.V. (Mortsel,
BE)
|
Family
ID: |
10431854 |
Appl.
No.: |
04/763,382 |
Filed: |
September 27, 1968 |
Foreign Application Priority Data
|
|
|
|
|
Sep 28, 1967 [GB] |
|
|
44,114/67 |
|
Current U.S.
Class: |
428/451; 428/452;
430/954; 428/510; 428/913 |
Current CPC
Class: |
G03G
5/142 (20130101); G03G 5/0553 (20130101); G03C
1/89 (20130101); G03G 5/14 (20130101); G03G
5/087 (20130101); G03C 1/93 (20130101); G03C
8/52 (20130101); G03G 5/10 (20130101); G03G
5/0571 (20130101); Y10S 428/913 (20130101); Y10T
428/31891 (20150401); Y10T 428/31667 (20150401); Y10S
430/155 (20130101) |
Current International
Class: |
G03G
5/10 (20060101); G03G 5/14 (20060101); G03C
8/00 (20060101); G03C 1/93 (20060101); G03G
5/087 (20060101); G03C 1/89 (20060101); G03C
1/91 (20060101); G03G 5/05 (20060101); G03C
8/52 (20060101); B32b 023/08 (); B32b 027/08 ();
G03c 001/80 () |
Field of
Search: |
;117/83,81,76F,164,138.8F ;260/8 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Martin; William D.
Assistant Examiner: Husack; Ralph
Claims
We claim:
1. Sheet material comprising a hydrophobic film support having
superposed thereon in succeeding order, a first layer directly
adherent to said hydrophobic film support and comprising a
copolymer formed from 45 to 99.5 percent by weight of at least one
vinylidene chloride or vinyl chloride monomer, from 0.5 to 10
percent by weight of an ethylenically unsaturated hydrophilic
monomer, and from 0 to 54.5 percent by weight of at least one other
copolymerizable ethylenically unsaturated monomer; and a second
layer comprising in a ratio of 1:3 to 1:0.5 by weight a mixture of
gelatin and a copolymer of 30 to 70 percent by weight of butadiene
with at least one copolymerizable ethylenically unsaturated
monomer.
2. Sheet material according to claim 1, wherein the copolymer of
said first layer contains up to 54.5 percent by weight of at least
one acrylamide, methacrylamide, acrylic acid ester, methacrylic
acid ester, maleic acid ester or N-alkylmaleimide monomer.
3. Sheet material according to claim 1, wherein the said first
layer is formed from a dried solution of a copolymer of vinylidene
chloride, N-tert.butyl-acrylamide, n-butylacrylate, and N-vinyl
pyrrolidone.
4. Sheet material according to claim 1, wherein the said first
layer is formed from a dried solution of a copolymer of vinylidene
chloride, N-tert.-butyl acrylamide, n-butyl acrylate and itaconic
acid.
5. Sheet material according to claim 1, wherein the said first
layer is formed from a dried solution of a copolymer of vinylidene
chloride, vinyl chloride and methacrylic acid.
6. Sheet material according to claim 1, wherein the said first
layer is formed from a dried solution of a copolymer of vinyl
chloride, n-butyl acrylate and itaconic acid.
7. Sheet material according to claim 1, wherein the said first
layer is formed from a dried latex of a copolymer of vinylidene
chloride, vinyl chloride, n-butyl acrylate and itaconic acid.
8. Sheet material according to claim 1, wherein the said second
layer is formed from a dried mixture of gelatin and a latex of a
copolymer of butadiene and at least one acrylonitrile, styrene,
acrylic acid esters, methacrylic acid esters or acrolein
monomer.
9. Sheet material according to claim 8, wherein the copolymer of
butadiene is a copolymer of butadiene and methyl methacrylate.
10. Sheet material according to claim 8, wherein the copolymer of
butadiene is a copolymer of butadiene and acrylonitrile.
11. Sheet material according to claim 8, wherein a matting agent
has been added to the mixture of gelatin and butadiene copolymer
latex.
12. Sheet material according to claim 11, wherein the matting agent
is finely divided silica.
13. Sheet material according to claim 8, wherein an antistatic
agent has been added to the mixture of gelatin and butadiene
copolymer latex.
14. Sheet material according to claim 1, wherein the hydrophobic
film support is a cellulose triacetate film.
15. Sheet material according to claim 1, wherein the hydrophobic
film support is a biaxially oriented polyethylene terephthalate
film.
16. Sheet material according to claim 1, wherein the first layer
has been applied to an unstretched polyethylene terephthalate film,
which is then oriented biaxially.
17. Sheet material according to claim 1, wherein the first layer
has been applied to a polyethylene terephthalate film oriented in
only one direction, which is then oriented in a direction
perpendicular to the first one.
18. Sheet material according to claim 1 including a separate
hydrophilic colloid layer containing gelatin on the side of said
second layer remote from said film support.
Description
This invention relates to sheet material which comprises a
hydrophobic support film and a layer system which is capable, if so
desired, of providing a bond between a hydrophilic layer and the
said hydrophobic support film, or which may itself provide a
vehicle for light-sensitive material as hereinafter described, and
particularly relates to film recording materials, films and foils
consisting of or comprising said sheet material.
In the following description and claims the terms "photographic
film elements" and "film recording materials" include elements and
materials for use in a variety of photoreproduction systems.
Examples of such systems include the well-known use of
light-sensitive silver halide emulsions, electrographic and
electrophotographic systems, and a recently developed
photosensitive system wherein the recording is effected by means of
photosensitive semiconductive substances.
In the said recently developed photosensitive systems, images are
produced by the action of electromagnetic radiation on
photosensitive semiconductor compounds, compositions or materials,
which are reversibly activated by patterns of radiations to create
a latent image of corresponding activated patterns. The latent
image is capable of producing a chemical reaction with a dissolved
reactant by an oxidation-reduction chemical process to form a
visible image (see "Unconventional Photographic Systems", Second
Symposium, Oct. 26-28, 1967, Washington D.C., pages 116-117).
In electrographic systems, electrostatic charges are applied to an
insulating surface. In such process an electrostatic charge pattern
is built up on an insulating layer, e.g., by means of a modulated
electron beam, while a conductive element, e.g., a conductive
support or layer stands in electrical contact with the backside of
said insulating layer, to which a voltage is applied. After the
patternwise charging of the insulating layer, the electrostatic
charge pattern is developed, for instance by the application of a
powder. Before powder development, the conductive backing element
may be removed if desired. An alternative development technique is
to bring about an imagewise deformation (ripple image) of the
insulating layer as hereinafter described.
In electrophotographic systems, the recording of images is based on
a differentiation in electrostatic charge condition, chargeability
or electrical conductivity, of a recording layer containing a
photoconductive substance, the said layer initially being
electrically insulating in the absence of light, but becoming
electrically conductive on exposure to light, and being in
electrical contact with an electroconductive support or layer. By
imagewise exposing the recording layer to imagewise modulated
activating electromagnetic radiation, a pattern of the said
differential charge condition is obtained. The electrostatic charge
images may be developed by an electrostatically attractable marking
material, or the conductivity images by electrolysis.
A particular technique of developing the latent image on a
recording layer from either an electrographic or an
electrophotographic process involves the deformation of the exposed
areas to produce a so-called "ripple image", by imagewise
distortion of the surface under the influence of a differential
electrical potential between the recording element and the backing
element, and reference may be made to United Kingdom Patent
specification No. 964,881; to "Photographic Science and
Engineering", Vol. 7, No. 1 (1963) pages 12-13; to RCA Review, Dec.
1964, pages 692-709, and to United Kingdom Patent application No.
5307/66.
In the manufacture of photographic film elements for use in silver
halide emulsion layer systems, it is common practice to apply to
the film support before the light-sensitive silver halide emulsion
layer or other colloid layers are applied, a thin subbing layer
consisting mainly of gelatin. If such a subbing layer is omitted,
the photographic emulsion layer or the other colloid layers will
not adhere sufficiently to the base.
The invention consists of a hydrophobic support film carrying
superposed thereon in succession, a layer (A) which is directly
adherent to the said hydrophobic support film and comprises a
copolymer formed from 45 to 99.5 percent by weight of at least one
of the chlorine-containing monomers vinylidene chloride and vinyl
chloride, from 0.5 to 10 percent by weight of an ethylenically
unsaturated hydrophilic monomer, and from 0 to 54.5 percent by
weight of at least one other copolymerizable ethylenically
unsaturated monomer; and a layer (B) comprising in a ratio of 1:3
to 1:0.5 by weight of a mixture of gelatin and a copolymer of 30 70
percent by weight of butadiene with at least one copolymerizable
ethylenically unsaturated monomer.
Hydrophobic support films suitable for use in the sheet material
according to the invention, include, e.g., a hydrophobic cellulose
ester, e.g., cellulose acetate, cellulose aceto-butyrate and
cellulose nitrate; or a highly polymeric linear polyester such as
for example polyethylene terephthalate, polystyrene or
polymethacrylic acid esters. Such hydrophobic support films are
coated with successive layers (A) and (B) according to the
invention to provide a layer system which may be used for a variety
of purposes. Thus the sheet material may be used for the
transference thereto of a hydrophilic layer. Thus in recording or
reproduction systems such a hydrophilic layer may be a stripped-off
hydrophilic layer carrying a relief pattern. The sheet material
according to the invention may be wetted with a liquid system
capable of providing a hydrophilic film thereon. Thus the sheet
material according to the invention may contain in the said layer
(B) photosensitive semiconductor compounds, compositions or
materials which are reversibly activated by patterns of radiations
to create a latent image, and the said liquid system may then be an
aqueous developing solution for the development of such a latent
image.
As described a hydrophilic layer may be applied to layer (B) of the
sheet material according to the invention which hydrophilic layer
may be, e.g., either transferred from another material or produced
thereon from a liquid system. Both layer (B) and the hydrophilic
layer when present, may contain one or more other substances, e.g.,
as follows;
a. semiconductive substance(s) in a suitable binding agent
b. electroconductive agent(s) in a suitable binding agent
c. pigment(s) in a photohardenable or photosolubilizable binder
d. matting agent(s) or opaque white pigment(s) in a suitable
binder
e. light-sensitive substance(s) including light-sensitive silver
halide, photoconductive substances, and other light-sensitive
compounds, e.g., diazonium salts and diazo-sulphonates
f. dissolved dye(s), e.g., a dye that is bleachable
g. color coupler(s) e.g., a color coupler that is used in silver
halide color photography
h. developing nuclei suited in the production of silver images
according to the silver halide complex diffusion transfer
process.
The sheet material according to the invention may be used as a
wrapping material, particularly when having layers thereon
particularly adapted to accept printing thereon, or the sheet
material may be used as tracing film.
Particularly useful recording materials are provided by sheet
material according to the invention, having hydrophilic pigment
coatings thereon, e.g., pigmented gelatin coatings suited for the
production of relief images, which are produced by means of a
photohardening or photo-solubilizing reaction. Such pigment
coatings are of practical interest in the graphic art more
particularly in the field known as "color proofing". Color proofing
materials serve to form a showing proof for submission for
approval, whereby an idea may be obtained of the multicolor
halftone reproduction which will finally be produced by the
successive printing in register with separate standard inks yellow,
magenta, cyan and black.
For ease of reference, the layer formed from the copolymer of
vinylidene chloride and/or vinyl chloride is hereinafter referred
to as the "vinylidene chloride copolymer" layer, and the layer
formed with the mixture of gelatin and butadiene copolymer is
hereinafter referred to as the "butadiene copolymer" layer.
The vinylidene chloride copolymer comprises from 0.5 to 10 percent
by weight of ethylenically unsaturated hydrophilic monomeric units.
These units may be derived from ethylenically unsaturated mono- or
dicarboxylic acids such as acrylic acid, methacrylic acid, and
itaconic acid. Other hydrophilic units, e.g., those derived from
N-vinyl pyrrolidone, may be present.
The vinylidene chloride copolymer may be formed from vinylidene
chloride and/or vinyl chloride and hydrophilic monomeric units
alone in the ratio indicated above. Preferably up to 54.5 percent
by weight of other recurring units, for instance acrylamides,
methacrylamides, acrylic acid esters, methacrylic acid esters,
maleic esters and/or N-alkyl-maleimides, may also be present.
Suitable vinylidene chloride copolymers are, e.g.,:
the copolymer of vinylidene chloride, N-tert.-butylacrylamide,
n-butyl acrylate, and N-vinyl pyrrolidone (70:23:3:4),
the copolymer of vinylidene chloride, N-tert.-butylacrylamide,
n-butyl acrylate, and itaconic acid (70:21:5:2),
the copolymer of vinylidene chloride, N-tert.-butylacrylamide, and
itaconic acid (88:10:2),
the copolymer of vinylidene chloride, n-butylmaleimide, and
itaconic acid (90:8:2),
the copolymer of vinyl chloride, vinylidene chloride, and
methacrylic acid (65:30:5),
the copolymer of vinylidene chloride, vinyl chloride, and itaconic
acid (70:26:4),
the copolymer of vinyl chloride, n-butyl acrylate, and itaconic
acid (66:30:4),
the copolymer of vinylidene chloride, n-butyl acrylate, and
itaconic acid (80:18:2),
the copolymer of vinylidene chloride, methyl acrylate, and itaconic
acid (90:8:2),
the copolymer of vinyl chloride, vinylidene chloride,
N-tert.-butylacrylamide, and itaconic acid (50:30:18:2).
All the ratios given between brackets in the above-mentioned
copolymers are ratios by weight.
The above copolymers are only examples of the combinations, which
can be made with the different monomers, and the invention is not
limited at all to the copolymers enumerated.
The different monomers indicated above may be copolymerized
according to various methods. For example, the copolymerization may
be conducted in aqueous dispersion containing a catalyst and an
activator. Alternatively, polymerization of the monomeric
components may occur in bulk without added diluent, or the monomers
are allowed to react in appropriate organic solvent reaction
media.
The vinylidene chloride copolymers may be coated on the hydrophobic
film base according to any suitable technique, e.g., by immersion
of the surfaces of the film into a solution of the coating
material. They may also be applied by spray, brush, roller, doctor
blade, air brush, or wiping techniques. The thickness of the dried
layer may vary between 0.3 and 3 .mu. preferably.
Various wetting or dispersing agents may be used when the
vinylidene chloride copolymer layer is applied from an aqueous
dispersion. These dispersions are obtained directly when the
copolymer has been made by an emulsion polymerization process. When
coating aqueous dispersions of vinylidene chloride copolymer on a
polyethylene terephthalate film support a very strong adherence to
the support is obtained when said dispersions are applied before or
during stretching of the polyethylene terephthalate film. The
aqueous dispersion may be applied to at least one side of the
nonstretched film, but may also be applied to polyethylene
terephthalate film which has been oriented biaxially. The
vinylidene chloride copolymer layer may also be coated on at least
one side of a polyester film, which has been stretched in only one
direction, e.g., longitudinally, whereafter the subbed polyester
film is stretched in a direction perpendicular thereto, in this
case transversally.
Finally, the biaxially oriented coated polyester film is provided
with the second subbing layer of the mixture of gelatin and
butadiene copolymer latex.
The butadiene copolymer comprises 30 to 70 percent by weight of
monomeric butadiene units. The balance is formed by units deriving
from other ethylenically unsaturated hydrophobic monomers, such as
acrylonitrile, styrene, acrylic acid esters, methacrylic acid
esters, and acrolein.
The butadiene copolymer is formed by emulsion polymerization and
the primary latex obtained is directly mixed with the aqueous
gelatin solutions in such a way that the ratio of gelatin to
butadiene copolymer in the dried layer varies between 1:3 parts and
1:0.5, all parts being by weight. To the mixture known plasticizers
for gelatin such as polyethylene oxides and glycerol may also be
added.
The mixture of aqueous gelatin solution and of butadiene copolymer
latex is coated onto the vinylidene chloride copolymer layer by
known means. The thickness of the dried layer generally varies
between 0.10 and 20 .mu..
The addition of a latex of a copolymer of butadiene and a lower
alkyl ester of acrylic or methacrylic acid to a gelatin-containing
layer of a photographic material has been described already in the
United Kingdom Patent specification No. 1,053,043. According to
this Patent specification the butadiene copolymer latex is added to
reduce the brittleness of the gelatin layer, to procure a higher
dimensional stability to the photographic material, wherein it is
used, and to decrease its curling tendency. However, it cannot be
deduced from this Patent Specification that the layer of gelatin
and butadiene copolymer latex combined with a vinylidene chloride
copolymer layer would procure an adequate subbing combination for
any hydrophobic film support, and especially for polyester film
supports.
The subbed film support consists of a hydrophobic film support and
the combination of the two anchoring subbing layers used according
to the invention. As mentioned before the hydrophobic film support
may be a film of cellulose triacetate, of polyethylene
terephthalate, of polycarbonate, of polystyrene, of polymethacrylic
acid ester, etc. The subbed hydrophobic film support may be
provided on only one side or on both sides with the combination of
subbing layers.
A colloid layer may be deposited on the subbed film support thus
obtained. This colloid layer may be a simple gelatin layer, a
gelatin silver halide emulsion layer, a gelatin filter layer, a
gelatin matting layer containing, e.g., finely divided silica, an
antistatic layer or an antihalation layer containing a hydrophilic
colloid binding agent. If an antistatic layer is deposited on the
subbed film support, known antistatic agents, e.g., salts, are
dispersed in the colloid binding agent, e.g., gelatin. In the
latter case too, these salts may be added already to the aqueous
gelatin solution, which is to be mixed with the butadiene copolymer
for the formation of the second layer of the subbing layer
combination.
In the manufacture of electrophotographic recording materials
containing a hydrophobic electrically insulating film support and a
photoconductive layer containing a photoconductive substance
applied in a binder, normally an electrically insulating binder, it
is necessary to apply between the photoconductive recording layer
and the said support an electrically conductive interlayer having a
conductivity substantially higher than the conductivity in the dark
of the photoconductive recording layer. Such an interlayer
preferably contains a hydrophilic colloid in combination with
antistatic or hygroscopic agents, e.g., those described in the U.S.
Pat. No. 3,148,982, conductive pigments, e.g., carbon black and/or
polyionic polymers, e.g., those containing quaternized nitrogen
atoms as described in the United Kingdom Patent specification No.
950,960. Good results are obtained with CALGON CONDUCTIVE POLYMER
261 manufactured by Calgon Corporation, Calgon Center Box 1346,
Pittsburgh, U.S.A. (Calgon is a registered Trademark). Such
antistatic or electroconductive hydrophilic colloid layers
perfectly adhere to hydrophobic film supports subbed according to
the present invention.
In the manufacture of interesting photochemically recording
materials, e.g., as described in the Belgian Patent specification
No. 655,384 and the published Dutch Patent application No. 6413011,
semiconductive light-sensitive pigments are dispersed in a binder
containing a hydrophilic colloid.
In the manufacture of interesting electrostatic recording
materials, e.g., as described in the United Kingdom Patent
application No. 16,459/66, now British Pat. No. 1,156,822, and the
published Dutch Patent application No. 6608816 a n-type
photoconductor pigment is dispersed in a binder having a
hydrophilic character.
A hydrophobic film support is firmly bonded to such pigment
coatings by means of the composite subbing layer according to the
present invention.
In all the above-described applications of the combination of
subbing layers according to the invention, at least one layer is
deposited on top of the butadiene copolymer layer. The layer
deposited thereon may be a simple hydrophilic colloid layer, e.g.,
a gelatin layer, a hydrophilic colloid layer containing
light-sensitive silver halide salts, a hydrophilic polymer or
colloid layer containing all kinds of special additives such as
antihalation dyestuffs, antistatic agents, electroconductive
pigments, photoconductive insulating pigments, photosensitive
semiconductive pigments and matting agents. All these additives may
also be added already to the coating composition of the butadiene
copolymer layer. Thus, there can be incorporated into the butadiene
copolymer layer finely divided silicium dioxide, photosensitive
titanium dioxide, photoconductive zinc oxide and carbon black.
According to a preferred embodiment these additives are dissolved
when they are soluble in the coating composition or homogeneously
dispersed in the mixture of aqueous gelatin solution and butadiene
copolymer latex before casting of the second subbing layer on top
of the vinylidene chloride copolymer layer. When the subbed
hydrophobic film support is to be used as a tracing film support,
there may be added to the butadiene copolymer layer, which already
contains a white pigment, e.g., titanium dioxide and/or silicium
dioxide, also urea-formaldehyde or melamine-formaldehyde resins to
render the surface of the layer more resistant to writing and
tracing operations.
In a particular embodiment of the invention a n-type
photoconductive substance, e.g., photoconductive zinc oxide is
dispersed in the butadiene copolymer layer and no further radiation
sensitive layers are deposited on top of the said layer. In this
way a photographic material is produced, which is suited for use
according to the process described in the United Kingdom Patent
application No. 16,459/66, now British Pat. No. 1,156,822.
According to a special and very interesting embodiment of the
invention a photosensitive semiconductor material is dispersed in
the butadiene copolymer layer and no further radiation-sensitive
layers are deposited on top of the said layer. In this way a
photographic recording material is obtained by which visible or
latent images can be formed in the absence of an externally applied
electric field by means of the imagewise modulated action of
electromagnetic radiation reversibly activating the photosensitive
semiconductor material in such a way that by means of a dissolved
reactant, a portion of which may be present in the recording
material before the exposure, images corresponding to the
light-activated pattern are produced by an oxidation-reduction
reaction, the said photosensitive semiconductor itself being
substantially chemically unchanged at the end of the process. So,
the recording material according to the present invention is
composed of a hydrophobic film support coated with the vinylidene
chloride copolymer layer and having thereon the butadiene copolymer
layer, in which the photosensitive semiconductor material is
dispersed. Photosensitive semiconductor compounds suited for use in
a process for producing visible or latent images by an
oxidation-reduction reaction as indicated above are described,
e.g., in the United Kingdom Patent specification No. 1,043,250,
which pertains to a related process. Titanium dioxide is of special
interest as semiconductor material, but other known semiconductors,
which become conductive on irradiation, can also be used, e.g.,
zinc oxide, zinc sulphide, lead monoxide, red lead oxide, silicium
dioxide, aluminum dioxide, chromium oxide, osmium oxide, and
cadmium sulphide.
In the said process the average particle size of the finely divided
semiconductors is important. Particle sizes not larger than 250
millimicrons and preferably comprised between 5 and 100
millimicrons are very advantageous.
The finely divided semiconductor is dispersed in the
above-described binder material consisting of gelatin and butadiene
copolymer in such a proportion that in the dried layer the ratio of
binding agent to semiconductor varies between 3:1 and 1:10 by
weight. The thickness of the radiation-sensitive coating applied on
the vinylidene chloride copolymer layer by known means should be
generally situated between 0.10 and 20 .mu. after drying.
Activation of the semiconductor surfaces is effected by exposure to
radiation of sufficient energy. Ultraviolet radiation having a
wavelength of less than approximately 4,000 A. is very appropriate.
However sensitization of the semiconductors, e.g., by doping with
foreign ions or dye sensitization techniques can be employed to
make the semiconductor sensitive to radiation in the visible
spectrum.
Exposure to a suitable source of radiation modified by an image
pattern establishes gradients of differential chemical reactivity
between the exposed and nonexposed portions and establishes an
image pattern in the exposed portions of the semiconductor
material. Said image pattern is reversible and can be erased
therefrom, e.g., by heating. It can also be made permanent by
bringing the activated portions in contact with suitable oxidizing
or reducing agents according to known techniques. This reaction
forms a visible image pattern.
The reversible image, which was obtained upon exposure to a source
of radiation need not be treated with the oxidizing or reducing
agents directly after exposure. It can be stored for a certain time
and at a later stage it can be erased or developed to produce
either positive or negative images corresponding with the image
stored in the exposed semiconductor. After development, the
semiconductor surface is thoroughly washed to remove any remaining
developer, whereupon the semiconductor surface can be reused if new
information should be added to the already developed image. For
development, numerous developers including silver ions, can be
employed.
If the degree of semiconductor activation is high, the quantity of,
e.g., metallic silver formed by reduction of silver ions by the
light-activated photoconductor will be sufficient to form a visible
image directly. If not so, a latent developed image is produced in
the semiconductor. Such an image is irreversible and can be stored
for long periods. It can also be intensified by an image
intensification development according to which, e.g., solutions
containing substances such as univalent silver ions, mercurous
ions, and mercuric ions, which are reducible by the light-activated
semiconductor to finely divided black-appearing metallic silver or
mercury, are used in combination with chemical redox systems,
preferably organic redox systems such as those containing
hydroquinone or p-monomethylamino-phenol sulphate.
After development the semiconductor surfaces are rendered incapable
of further development by thoroughly washing, e.g., in water
containing a solubilizing or complexing agent to aid removal of
residual developer. In an analogous manner as in the fixing
solutions employed in silver halide photography, such solutions
solubilize the remaining developer, e.g., silver ion, and they
facilitate the removal thereof by washing.
In contradistinction with the above-described process for forming
an irreversible image in a semiconductive layer, it is also
possible to soak the semiconductive layer before the exposure with
a solution of the developer. In this way there is immediately
obtained an irreversible image upon exposure.
When hydrophobic film, e.g., polyester film was used as the support
for the radiation-sensitive semiconductor coating, at least two
subbing layers were needed hitherto, to obtain a sufficient
adhesion between the semiconductor coating and the support. The
possibility of incorporating the photosensitive semiconductive
substances in one of the subbing layers offers the considerable
advantage, that but two subbing layers must be applied. With these
two subbing layers the adhesion as well as the photographic
properties are excellent.
The following examples illustrate the present invention.
EXAMPLE 1
In a reaction flask equipped with a stirrer, a nitrogen inlet, a
dropping funnel, and a condenser were placed 10 liters of water and
2.88 liters of a 10 percent aqueous solution of the sodium salt
sulphonated dodecyl benzene. Then the reaction flask was rinsed
with nitrogen and the liquid was heated to 60.degree. C. In another
flask were placed successively 800 cc. 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 was stirred and brought to dissolution by gentle
heating.
Through the dropping funnel a solution was added of 21.6 g. of
ammonium persulphate in 400 cc. of water. Immediately pumping of
the monomer solution into the reaction flask was started. The rate
of pumping was such that after 75 min. all the monomer solution was
pumped over. Together with the monomer solution a further amount of
ammonium persulphate solution was added dropwise (64.8 g. in 1,200
cc. of water). During the whole reaction period the temperature of
the mixture was maintained at 60.degree. C. while refluxing. After
all the monomer had been added, again an amount of 21.6 g. of
ammonium persulphate dissolved in 400 cc. of water was added at
once. After refluxing, stirring was continued for another 30 min.
at 60.degree. C., whereupon the reaction mixture was 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 was 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 was
obtained was repeatedly washed with water and finally dried.
An amount of 2.5 g. of the vinylidene chloride copolymer formed
above were dissolved in a mixture of 90 cc. of butanone and 10 cc.
of nitroethane. The solution obtained was 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 was present per sq.m. This layer was
dried at room temperature.
To the subbing layer obtained a second layer was applied at
35.degree. to 50.degree. C. in a ratio of 0.4 to 0.6 g./sq.m from
the following composition:
20 % latex of copolymer of butadiene and methyl methacrylate
prepared as described hereinafter 10 g. gelatin 1 g. water 55 ccs.
acetone 40 ccs. methyl glycol 5 ccs.
After drying, a light-sensitive gelatin silver halide emulsion
layer as commonly used in the graphic art was applied to this
layer. The layers of the photographic material manufactured in this
way showed a good adherence before, during as well as after
processing in the photographic baths.
The copolymer latex was prepared as follows:
In a 20 liters autoclave were 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 was
polymerized for 6 h. at 60.degree. C. This polymerization was
slightly exothermic for a short while. Then the pressure dropped
rapidly. The polymerization was finished under reduced pressure.
The latex of the copolymer of butadiene and methyl methacrylate
(50:50) was 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 was cooled and filtered.
EXAMPLE 2
To a cellulose triacetate film a layer was applied at a ratio of
0.75 to 1 g./sq.m from the following composition at 25.degree.
C:
copolymer of vinylidene chloride, N-tert.-butyl-acrylamide, n-butyl
acrylate, and N-vinyl pyrrolidone of example 1 2 g. acetone 50 ccs.
ethyl acetate 10 ccs. methanol 10 ccs. ethanol 10 ccs. butanone 10
ccs.
A second layer was applied to the resulting dried layer in a ratio
of 0.4 to 0.6 g./sq.m at 35.degree.-50.degree. C. from the
following composition:
20 % latex of copolymer of butadiene and methyl methacrylate of
example 1 5 g. gelatin 1 g. water 60 ccs. methanol 40 ccs.
A light-sensitive gelatin silver halide emulsion layer was coated
thereon.
The layers of the photographic material thus obtained possessed an
excellent adherence in wet as well as in dry state.
EXAMPLE 3
In an autoclave were placed 1,650 cc. of water and 9.6 g. of
itaconic acid. After dissolution a solution of 6 g. of sodium
hydrogen carbonate in 120 cc. of water was added. Subsequently 98
cc. of a 10 percent aqueous solution of the disodium salt of
disulphonated dodecyl diphenyl ether and 49 cc. of a 10 percent
aqueous solution of the sodium salt of sulphonated dodecyl benzene
were added as emulsifying agents. Then 96 g. of n-butyl acrylate,
144 g. of vinylidene chloride, 9.8 g. of ammonium persulphate, and
4.9 g. of potassium metabisulphite were added. The autoclave was
sealed and stirring started. Under nitrogen pressure 240 g. of
vinyl chloride were pressed into the autoclave, which was then
heated to 50.degree. C., while stirring. When this temperature had
been reached, stirring was continued for 15 to 30 min. The
temperature of the latex rose to about 65.degree. C. The reaction
was continued for about 3 h. whereupon the latex was cooled to room
temperature. The pH thereof amounted to 2.6 and was brought to 6 by
means of 100 cc. of 1N aqueous sodium hydroxide. It was very well
filterable and consisted of the copolymer of vinylidene chloride,
vinyl chloride, n-butyl acrylate, and itaconic acid (30:50:18:2) in
a concentration of 20 percent.
To an extruded polyethylene terephthalate film, which had been
stretched longitudinally up to three times its original length, a
subbing layer was applied in a ratio of about 2 g./sq.m from an
aqueous suspension containing:
20 % latex of copolymer of vinylidene chloride, vinyl chloride,
n-butyl acrylate and itaconic acid (30:50:18:2) (manufactured as
above) 500 g. finely divided silica 5 g.
The film coated in this way was then stretched transversely up to
three times its original width, whereupon a second subbing layer
was applied in a ratio of 0.4 to 0.6 g./sq.m at
35.degree.-50.degree. C. from the following composition:
20 % latex of copolymer of butadiene and methyl methacrylate of
example 1 7.5 g. gelatin 1 g. water 60 ccs. methanol 40 ccs.
This subbed film was provided with a light-sensitive gelatin silver
halide emulsion layer as commonly used for graphic purposes. The
layers of photographic material thus obtained possessed a good
adherence before as well as after processing.
EXAMPLE 4
To one side of a biaxially oriented polyethylene terephthalate film
of 180 .mu. thickness a layer was applied at 25.degree.-30.degree.
C. in a ratio of 1.5 to 1.75 g./sq.m from the following
composition:
copolymer of vinylidene chloride, N-tert.-butyl-acrylamide, n-butyl
acrylate, and N-vinyl pyrrolidone of example 1 5.5 g. methylene
chloride 65 ccs. dichloroethane 35 ccs.
After drying of the first layer, a second layer was applied thereto
in a proportion of 0.4 g./sq.m from the following composition:
20 % latex of copolymer of butadiene and methyl methacrylate of
example 1 6.25 g. gelatin 1 g. water 43 ccs. silica 0.5 g.
polystyrene sulphonic acid 1.8 g. methanol 40 ccs.
A gelatin silver halide emulsion layer as used in photographic
X-ray material was then coated on this antistatic layer. The layers
of the photographic material thus obtained possessed a good
adherence in all circumstances.
EXAMPLE 5
To both sides of a biaxially oriented polyethylene terephthalate
film of 100 .mu. thickness a layer was applied from the following
composition at 25.degree.-30.degree. C.:
copolymer of vinylidene chloride, N-tert.-butylacrylamide, n-butyl
acrylate, and itaconic acid (70:21:5:4) prepared analogously to the
vinylidene chloride copolymer of example 1 7 g. methylene chloride
65 ccs. dichloroethane 35 ccs.
This coating composition was applied in such a way that the dried
layer had a thickness of 1.5 to 1.75 .mu.. To both subbing layers a
layer was applied in a proportion of 0.4 to 0.6 g./sq.m from the
following composition at 35.degree.-50.degree. C.:
20 % latex of copolymer of butadiene and styrene (60:40) prepared
ana- logously to the latex of the copoly- mer of butadiene of
example 1 gelatin 1 g. water 60 ccs. methanol 40 ccs.
A light-sensitive gelatin silver halide emulsion layer as commonly
used in the graphic art was applied to one of the coated sides of
the resulting dry material. An antihalation layer of gelatin and
manganese dioxide was coated on the backside of the material. The
layers of the photographic material thus obtained showed a very
good adherence in wet as well as in dry state.
EXAMPLE 6
Example 5 was repeated, with the difference, however, that the
coating composition for the second subbing layer was replaced by
the following one:
20 % latex of copolymer of butadiene and ethyl acrylate (50/50)
6.25 g. gelatin 1 g. water 60 ccs. ethanol 40 ccs.
The adherence of the layers of the material obtained was
excellent.
EXAMPLE 7
Example 5 was repeated, with the difference, however, that the
coating composition of the second subbing layer was replaced by the
following one:
20 % latex of copolymer of butadiene, ethyl acrylate and acrolein
(55:40:5) 6 g. gelatin 0.80 g. water 60 ccs. methanol 40 ccs.
The adherence of the layers of the material was excellent.
EXAMPLE 8
Example 5 was repeated, but the coating composition of the second
subbing layer was replaced by the following one:
20 % latex of butadiene and acrylo- nitrile (60:40) 6 g. gelatin
0.80 g. water 60 ccs. methanol 40 ccs.
The adherence of the layers of the material obtained was
excellent.
EXAMPLE 9
Example 5 was repeated, but the coating composition of the second
subbing layer was replaced by the following one:
20 % latex of copolymer of butadiene and ethyl hexyl acrylate
(60:40) 6 g. gelatin 0.80 g. water 60 ccs. methanol 40 ccs.
The adherence of the layers of the material obtained was
excellent.
EXAMPLE 10
To a biaxially oriented polyethylene terephthalate film of 180 .mu.
thickness a layer was applied at 25.degree. C. in a proportion of 2
g./sq.m from the following composition:
copolymer of vinyl chloride, n-butyl acrylate, and methacrylic acid
(70:26:4) 8 g. methylene chloride 80 ccs. dichloroethane 20
ccs.
A second layer was applied thereto at 25.degree. C. in a proportion
of 0.6 g. per sq.m from the following coating composition:
20 % latex of copolymer of butadiene and ethyl acrylate (50:50)
6.25 g. gelatin 1 g. water 60 ccs. methanol 40 ccs.
The dried combination of subbing layers was coated successively
with an antistatic gelatin layer and a light-sensitive gelatin
silver halide emulsion layer as commonly used in X-ray photographic
material. The layers of the material thus obtained showed an
excellent adherence before, during as well as after processing.
EXAMPLE 11
To a biaxially oriented polyethylene terephthalate film of 180 .mu.
thickness a layer was applied at 25.degree. C. in a proportion of 1
g./sq.m from the following coating composition:
copolymer of vinylidene chloride, n-butyl-maleimide and itaconic
acid (90:8:2) 8 g. methylene chloride 80 ccs. dichloroethane 20
ccs.
To this layer a second layer was applied at 35.degree. C. in a
ratio of 0.4 to 0.6 g./sq.m from the following composition:
20 % latex of copolymer of buta- diene and n-butyl acrylate (70:30)
6 g. gelatin 0.80 g. water 60 ccs. methanol 40 ccs.
This layer was coated successively with a known antistatic gelatin
layer and a light-sensitive gelatin silver halide emulsion layer as
commonly used in X-ray material. The adherence of the layers was
excellent.
EXAMPLE 12
To one side of a nonstretched polyethylene terephthalate film of
about 1 mm. thickness a layer was applied at 25.degree. C. in a
proportion of about 5 g./sq.m from a latex of a copolymer of vinyl
chloride, n-butyl acrylate, and itaconic acid (66:30:4).
This subbed film was simultaneously stretched longitudinally and
transversally to about ten times its original size. Another layer
was applied at 40.degree. C. to the vinylidene chloride layer in a
proportion of 0.4 to 0.6 g./sq.m from the following coating
composition:
20 % latex of copolymer of butadiene and ethyl hexyl acrylate
(60:40 ) 6 g. gelatin 0.80 g. water 60 ccs. methanol 40 ccs.
The dried material was then coated with a gelatin silver halide
emulsion layer as commonly used for graphic purposes. The graphic
material formed possessed an excellent adherence of the layer in
dry as well as in wet state.
EXAMPLE 13
A first subbing layer as described in example 4 and a second
subbing layer as described in example 3 were applied successively
to a biaxially stretched polyethylene terephthalate support of 100
.mu. thickness. The resulting material was then coated with a
light-sensitive layer prepared as follows:
120 g. of zinc oxide was dispersed while stirring thoroughly in 700
ml. of demineralized water, to which 2 g. of sodium
hexametaphosphate had been added. A solution of 80 g. of gelatin in
820 g. of demineralized water, 10 g. of a 12.5 percent solution of
saponine in demineralized water, and 10 g. of a 20 percent solution
of formaldehyde in demineralized water were added at 40.degree. C.
The mixture was then coated in a ratio of approximately 2 g. of
zinc oxide per sq.m.
The dried light-sensitive material was exposed image-wise through a
transparent original and dipped in the following baths:
5 seconds in a 5 percent solution of silver nitrate in
demineralized water;
5 seconds in a 0.6 percent solution of p-monomethylaminophenol
sulphate in demineralized water;
30 seconds in an acid fixing bath containing 200 g. of sodium
thiosulphate 5 aq. and 25 g. of potassium metabisulphite per
liter.
Subsequently the material was rinsed for 5 minutes in running water
and then dried. A black negative image of the original was
obtained.
EXAMPLE 14
A biaxially oriented polyethylene terephthalate support having a
thickness of 100 .mu. was coated with a subbing layer consisting of
a solution in dichloroethane of a copolymer of vinylidene chloride,
N-tert.-butylacrylamide, n-butyl acrylate, and vinyl pyrrolidone
prepared as described in example 1, in such a way that the
resulting dried layer had a thickness of 1 .mu..
30 g. of titanium dioxide having a particle size of 15 to 40 m.mu.
and a specific surface of approximatively 50 sq.m./g. were stirred
for 2 min. with 150 cc. of demineralized water and 0.5 g. of sodium
hexametaphosphate by means of an Ultra-Turrax stirrer, so that an
homogeneous dispersion was produced. To the resulting mixture a
solution at 30.degree. C. of 12.5 g. of gelatin in 412.5 cc. of
demineralized water and a 20 percent by weight latex of a copolymer
of butadiene and methyl methacrylate prepared as described in
example 1 were added successively while stirring. Finally, 250 cc.
of demineralized water at 30.degree. C. were added.
The resulting pigment dispersion was applied to the polyester film
subbed with vinylidene chloride copolymer in such a proportion that
1.59 g. of titanium dioxide were present per sq.m. of the
layer.
The dried material was then exposed image-wise through a
transparent original and dipped successively in the following
baths:
1. 30 sec. in a 10 percent by weight solution of silver nitrate in
demineralized water;
2. 30 sec. in a 3 percent by weight solution of
p-monomethylamino-phenol sulphate in demineralized water;
3. 60 sec. in an acid fixing bath containing 200 g. of sodium
thiosulphate 5 aq. and 25 g. of potassium metabisulphite per
liter.
A sharp black negative silver image of the exposed original was
obtained upon rinsing and drying.
EXAMPLE 15
One side of a biaxially oriented polyethylene terephthalate film
having a thickness of 180 .mu. was coated with the following
composition at 25.degree.-30.degree. C. in a ratio of 1.5 to 1.75
g./sq.m:
copolymer of vinylidene chloride, N-tert.-butylacrylamide, n-butyl
acrylate, and N-vinyl pyrrolidone prepared as described in example
1 5.5 g. methylene chloride 65 ccs. dichloroethane 35 ccs.
The resulting layer was coated with a mixture of 95 parts by weight
of water and 5 parts by weight of ethylenechlorhydrin, which
mixture comprises 13.5 percent by weight of titanium dioxide, 1.6
percent by weight of gelatin, and 5 percent by weight of a latex of
the copolymer of butadiene and methylmethacrylate (50:50 percent by
weight) prepared as described in example 1. Upon drying the layer
formed had a thickness of 4-5 .mu.. The coating composition was
prepared as follows: 2,025 g. of titanium dioxide was dispersed in
7,500 cc. of water with 37 cc. of hexametaphosphate as dispersing
agent. The dispersion was stirred fastly for 10 min. at
5.degree.-15.degree. C. and then heated to 35.degree. C. A 10
percent by weight aqueous solution of gelatin was added thereto
while stirring rapidly. The following composition was then added
while stirring slowly to avoid scumming:
10 percent aqueous solution of gelatin 2600 ccs. water 300 ccs. 20
% by weight latex of the copolymer of butadiene and methyl
methacrylate prepared as described in example 1 3750 ccs. 10 % by
weight aqueous solution of the sodium salt of oleylmethyltauride
225 ccs. ethylenechlorhydrin 750 ccs.
Before coating the dispersion having a viscosity at 35.degree. C of
8 cp. was filtered.
The butadiene copolymer layer was then covered with a gelatin
silver halide emulsion layer as known in the graphic art. The thus
formed photographic material can be used whenever a dimensionally
stable support is needed and whenever the favorable light
reflection characteristics of the titanium dioxide layer are
needed.
In certain applications the titanium dioxide can be replaced by
other pigments, e.g., silicium dioxide.
EXAMPLE 16
In the same way as in example 15, a biaxially oriented polyester
film is coated with a layer of a vinylidene chloride copolymer. The
resulting layer was coated with a composition comprising 3 percent
by weight of carbon black, 1 percent by weight of gelatin, and 3
percent by weight of the copolymer of butadiene and methyl
methacrylate prepared as described in example 1.
This composition was prepared as follows:
187.5 cc. of a 16 percent by weight aqueous dispersion of carbon
black comprising 2 percent by weight of poly-N-vinyl pyrrolidone
wasdiluted with 300 cc. of water. 5 cc. of a 40 percent by weight
latex of the copolymer of ethyl acrylate and N-vinyl pyrrolidone
(90:10 percent by weight) and 100 cc. of a 10 percent by weight
aqueous solution of gelatin were added thereto at 35.degree. C. The
mixture was stirred rapidly for 5 min. A mixture at 35.degree. C.
of 150 cc. of a 20 percent by weight latex of the copolymer of
butadiene and methyl methacrylate prepared as described in example
1, 15 cc. of a 10 percent by weight aqueous solution of the sodium
salt of oleylmethyltauride, 5 ml. of a 40 percent by weight latex
of the copolymer of ethyl acrylate and N-vinyl pyrrolidone (90:10
percent by weight), and 187.5 ml. of water were added thereto while
stirring slowly. Subsequently 50 ml. of methanol were added. The
mixture was then filtered while warm.
The vinylidene chloride copolymer layer was coated with this
composition so that upon drying a layer having a thickness of 4-5
.mu. was formed.
The latter layer was then coated successively with a gelatin
subbing layer and a high-sensitive gelatin silver halide emulsion
layer having a soft gradation.
The black-pigmented photographic material could be used for
producing images according to a silver complex diffusion transfer
process, wherein the sandwich formed by the light-sensitive and the
image-receiving layer can be removed from the camera or the
cassette during development of the negative image and during the
positive image formation by diffusion transfer.
* * * * *