Process for forming an image

A process for forming an image is disclosed wherein a photosensitive image-forming material comprising a diazonium compound or an azide compound is exposed and developed by a peeling development method wherein a development carrier sheet having thereon a layer of an adhesive composition is adhered to the image-forming material, before or after exposure, and, after exposure, peeled from the image-forming material whereby the exposed areas of the photosensitive layer are adhered to the carrier sheet thereby forming a relief image, and the unexposed areas remaining adhered to the support also forming a relief image.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a process for forming an image, and especially, 
to a method for obtaining a relief image which comprises imagewise 
exposing a photosensitive image-forming material and subjecting it to dry 
development. 
2. Brief Discussion of the Prior Art 
The present invention relates to a process for forming an image, which 
comprises imagewise exposing a photosensitive image-forming material 
composed of a support having formed thereon a layer of a photosensitive 
composition containing a diazonium compound or an aromatic azide compound 
and a thermoplastic binder and adhering the photosensitive composition 
layer closely to a development carrier sheet having a layer of an adhesive 
composition; or imagewise exposing said photosensitive image-forming 
material with said carrier sheet in intimate contact; and then peeling 
said image-forming material and said carrier sheet from each other to 
transfer and adhere the exposed area of the photosensitive composition 
layer to the carrier sheet and thereby form a relief image on it, and 
simultaneously form a relief image corresponding to the non-transferred, 
non-exposed area of the photosensitive composition on the support. 
Many methods for forming images by the dry-method development of a 
photosensitive compositions have been suggested heretofore which include, 
for example, developing an exposed photosensitive material by heating a 
"thermodeveloping method", with a suitable radiation ray, with a gas, with 
an electrostatic treatment, and by the application of pressure. 
One typical dry developing method is a so-called peeling development 
process wherein a photosensitive image-forming material composed of a 
support, a layer of a photosensitive composition on the support and a 
cover sheet placed on the photosensitive layer in which the adhesion of 
the photosensitive layer to the support and to the cover sheet changes by 
exposure, and after exposure, peeling the support and the cover sheet from 
the photosensitive layer to leave only the exposed area on the support or 
the cover sheet and the unexposed area on the other, both as a relief 
image. 
The method of image formation by peeling development is operated in the dry 
state, and the operation is simpler than ordinary liquid development using 
a large quantity of water or solvent. Furthermore, only the image area of 
the photosensitive image-forming composition which remains on the support 
after peeling, the non-image area is removed from the support by the 
peeling operation. Accordingly, this method has the advantage that the 
stabilization of the non-image area essential to photosensitive materials 
developed by an ordinary liquid developing method or thermodeveloping 
method, that is, its fixation, can be performed simultaneously with the 
developing operation. Since in the peel developing method, the 
photosensitive composition in the non-image area is fixed to the peel 
sheet as a solid layer, it can be disposed of easily, and this is 
desirable from the standpoint of environmental preservation. When the 
composition contains useful ingredients, they can be completely recovered 
and easily reused. Thus, this processing method is advantageous from the 
viewpoint of saving resources, too. 
Since a general procedure for image formation by peeling was published in 
Japanese Patent Publication No. 9663/63, a number of specific techniques 
have been suggested. These techniques are classified by their basic 
characteristics, and briefly described below. 
A three-layer structure composed of a support, a photosensitive layer on it 
containing a photopolymerizable monomer and a cover sheet laminated to the 
photosensitive layer constitutes a very important field in the art. Peel 
development of this photosensitive material is performed by utilizing the 
fact that polymerization proceeds in the exposed area of the material, 
and, therefore, the adhesion of the photosensitive layer to the support 
and to the cover sheet differs between the exposed area and unexposed 
area. It is described, for example, in Japanese Patent Publication No. 
3193/62 (U.S. Pat. No. 3,060,024), Japanese Patent Publication No. 
22901/68 (U.S. Pat. No. 3,353,955), Japanese Patent Application (OPI) No. 
7728/72 (The term "OPI" as used herein refers to a "published unexamined 
Japanese patent application") (U.S. Pat. No. 3,770,438), and U.S. Pat. 
Nos. 3,060,023 and 3,525,615. U.S. Pat. Nos. 3,627,529, 3,591,377 and 
3,607,264, etc., disclose a similar peel-developable photosensitive 
material consisting essentially of a support, a photosensitive layer and a 
transparent cover sheet in which the photosensitive composition layer 
contains a photocurable polyester (U.S. Pat. No. 3,591,377), a 
photocurable olefin compound (U.S. Pat. No. 3,607,264) or a photocuring 
catalyst and a thiol-containing olefin polymer (U.S. Pat. No. 3,627,529). 
The methods described above perform peel development by utilizing changes 
in adhesion incident to the photochemical reaction of a photopolymerizable 
monomer or a photocurable compound. 
Methods using other photosensitive compounds are also known. For example, 
Japanese Patent Application (OPI) No. 57819/77 discloses a method which 
comprises using a laminate structure composed of a sheet consisting of a 
support and an adhesive composition layer formed thereon, and a 
transparent plastic film coated with a photosensitive composition 
comprising a diazonium salt and a binder, exposing the laminate structure, 
and then peeling the film thereby to leave the unexposed area of the 
photosensitive composition layer on the transparent plastic film and the 
exposed area on the support. 
Japanese Patent Application (OPI) No. 3215/78 discloses an invention 
relating to a method which uses a similar sheet composed of a support and 
an adhesive composition layer formed thereon. A thin film layer comprising 
a metal or chalcogen is further provided between the support and a 
photosensitive composition layer to form a five-layer laminate structure. 
It utilizes the phenomenon that peel development after exposure induces 
selective separation at the interface between the non-sensitive thin film 
layer and the support. 
In the invention disclosed in Japanese Patent Application (OPI) No. 
23632/78, a photosensitive composition containing a polyhalogen compound 
and a polymer having a phenol nucleus is used, and by peeling a 
transparent film-like material adhering to the photosensitive composition 
layer before or after exposure, an image corresponding to the exposed 
image is obtained on the support. 
British Pat. No. 1,319,295 discloses a peel developing method which 
comprises laminating a heat-softenable polymeric layer and a powder 
capable of absorbing infrared rays to a support, exposing the resultant 
material to infrared rays to impart tackiness imagewise to the 
heat-softenable polymeric layer, and separating the polymeric layer from 
the support to form an image on the support. 
So far, the characteristics of known techniques about image formation by 
peeling have been described. Hetertofore, the basic principle of peel 
development has been considered to lie in the changing of the adhesion 
between the photosensitive composition layer and the support by light. For 
example, according to peel development, a photopolymerizable or 
photocurable photosensitive composition is used, and by a photochemical 
composition at the exposed area, the adhesion of the photosensitive layer 
to the support is decreased or increased from that before exposure, 
whereby the exposed area and the unexposed area are formed as images 
separated on different supports. Accordingly, a method for forming an 
image was suggested which comprises exposing a photosensitive composition 
in intimate contact with a cover sheet and peeling the cover sheet by 
utilizing the fact that the photosensitive adhesive layer has suitable 
tackiness at room temperature. 
On the other hand, Japanese Patent Application (OPI) Nos. 57819/77 and 
141003/76 and 3215/78 (U.S. patent application Ser. No. 810,828, filed 
June 28, 1977), for example, disclose a method in which the adhesive 
quality of the photosensitive composition layer itself is not essential. 
The adhesion required for peeling development is obtained by providing a 
cover sheet with a pressure-sensitive adhesive layer. The adhesive cover 
sheet is adhered intimately to the photosensitive composition layer before 
or after imagewise exposure, and then peeled off. Accordingly, a broader 
range of selection for the characteristics of the photosensitive 
composition is possible than the aforesaid methods which use a 
photopolymerizable compound as a material and utilize the tackiness of the 
photosensitive composition layer itself at ordinary temperatures. 
Some techniques which perform the separation of an image more effectively 
by heating the image-forming material at the time of peeling have been 
disclosed. For example, U.S. Pat. No. 3,060,023 discloses a method which 
comprises using a mixture of a photopolymerizable monomer and a 
thermoplastic polymer as a photosensitive composition layer, and 
afterexposure, bringing the photosensitive layer into intimate contact 
with a receptor sheet at a temperature of at least 40.degree. C. thereby 
to soften the unexposed area, i.e., the unpolymerized area of the 
photopolymerizable monomer, selectively and to transfer the image 
thermally onto the receptor sheet. It is clearly seen from the disclosure 
of the specification that this technique utilizes the transfer of the 
unexposed area (unpolymerized area) of the thermoplastic 
photopolymerizable composition to the receptor sheet under heat, and it 
affords a number of copies by bringing the exposed photopolymerizable 
composition layer into contact with a suitable support to transfer the 
unexposed area under heat. Since in this method a transfer image composed 
of the unpolymerized area is always utilized as an image, when it is 
desired to utilize the image obtained on the support further for a 
printing plate or a photoresist, it is necessary to provide an additional 
step of curing the transferred image by an after-treatment such as 
exposure. 
Japanese Patent Application (OPI) No. 39025/76 discloses a method which 
comprises imagewise exposing a three-layer image-forming material composed 
of a metal substrate, a layer of a photosensitive composition comprising 
an addition-polymerizable monomer and polyvinyl butyral and a cover sheet, 
and peeling the exposed material while heating it, thereby to induce 
cohesive destruction of the unexposed area (i.e., unpolymerized area) of 
the photosensitive layer and to obtain the same positive image as used in 
imagewise exposure on the metal substrate which image is utilized as a 
photoresist image. 
Thus, there have been examples in which heating is performed at the time of 
peeling. All of these examples use a layer of a photopolymerizable 
composition, and facilitate the transfer of an image to an image-receiving 
sheet by increasing the flowability of the unexposed area through heat. 
The present invention relates to a process for forming an image, which 
comprises imagewise exposing a photosensitive image-forming material 
composed of a support and formed thereon a layer of a photosensitive 
composition containing a diazonium compound or an aromatic azide compound 
and a thermoplastic binder and then adhering the photosensitive 
composition layer closely to a carrier sheet having a layer of an adhesive 
composition; or imagewise exposing said photosensitive image-forming 
material in intimate contact with said carrier sheet; and then peeling 
said image-forming material and said carrier sheet from each other to 
transfer and adhere the exposed area of the photosensitive composition 
layer to the development carrier sheet and to form a relief image on it, 
and simultaneously form a relief image corresponding to the 
non-transferred, non-exposed area of the photosensitive composition on the 
support. 
Japanese Patent Application (OPI) No. 57819/77 discloses a method for image 
formation by peeling operation in which a diazonium compound is used as a 
photosensitive substance. This method relies upon a photosensitive 
image-forming material composed of a support, an adhesive composition 
thereon, a photosensitive layer and a transparent plastic film, and 
comprises peeling the plastic film from the laminate after imagewise 
exposure whereby the unexposed area of the photosensitive composition 
layer adheres to the adhesive layer, and the exposed area of the 
photosensitive composition layer remains on the support. While the 
photosensitive composition used in conventional image-forming methods by a 
peeling operation are limited to photopolymerizable or photohardenable 
compositions, the Japanese (OPI) relies on a film having an dhesive 
composition layer as a means for obtaining relief images upon peeling 
development of a photosensitive composition layer composed of a 
combination of 4-(p-tolylthio)-2,5-dibutoxybenzenediazonium chloride/zinc 
chloride double salt or an aromatic azide compound and a binder polymer. 
In this invention, the exposed areas of the photosensitive composition 
remain on the support and the corresponding unexposed areas adhere 
adhesive composition layer on the carrier sheet, as a separate relief 
image. 
SUMMARY OF THE INVENTION 
A principal object of the present invention is to provide a process for 
forming a relief image by peeling development wherein photosensitive 
materials, previously felt unsuitable for peeling development methods, are 
used. 
Another object of the present invention is to provide a process for peeling 
development wherein the photosensitive composition is not adhesive or 
tacky at room temperature. 
A further object of the present invention is to provide a process for 
forming images wherein a photosensitive material comprising diazonium 
compounds or azide compounds is exposed and developed by a peeling 
development method. 
Still a further object of the present invention is to provide a process for 
forming images wherein it is not required to cover the image-forming 
material with a cover sheet prior to exposure such that intimate contact 
can be achieved between the image-forming material and the original image 
transparency. 
Another object of the present invention is to provide a process for forming 
relief images suitable for use in forming printing plates, printed 
circuits, etc. 
The present inventors have made extensive investigations, and found that by 
imagewise exposing a photosensitive image-forming material composed of a 
support and a layer of a photosensitive composition composed of a 
diazonium compound or an aromatic azide compound and a binder through an 
original image positive transparency, adhering the exposed material 
closely to a development carrier sheet containing a layer of an adhesive 
composition, and then peeling the two elements from each other, a positive 
relief image of good quality can be formed on the support. This has led to 
the accomplishment of the present invention. 
The invention will be described in detail hereinbelow.

DETAILED DESCRIPTION OF THE INVENTION 
The photosensitive composition used in this invention comprises a diazonium 
or aromatic azide compound and a binder. If desired, it may contain 
additives to preserve and stabilize the photosensitive substances, color 
the image, increase the peeling development performance or to render the 
images visible, or for other purposes. 
One characteristic feature of this invention is the use of a carrier sheet 
having a layer of an adhesive composition in peeling development. 
The use of a layer of an adhesive composition for peeling development is 
described in Japanese Patent Application (OPI) No. 57819/77. In this 
method, the image-forming material has a four-layer structure of a 
support, a photosensitive image-forming layer, an adhesive composition 
layer and a carrier film for the adhesive layer. The method produces 
positive image on the support by combining a specific diazonium or azide 
compound and a binder and using a negative transparency. 
In contrast, according to the process of this invention, a broader range of 
diazonium compounds or aromatic azide compounds can be used as 
photosensitive compounds by properly selecting the support. 
Another characteristic feature of this invention which distinguishes it 
from OPI 57819/77 is that the layer of the photosensitive composition is a 
solid layer and is not tacky at ordinary temperatures (e.g., about 
5.degree. to about 40.degree. C.). Since it is not tacky, it is not 
necessary to apply the cover sheet, which is essential to using a 
photosensitive composition layer containing a photopolymerizable monomer 
flowable or tacky at room temperature, before or during exposure. 
Accordingly, the transparency and the photosensitive composition layer can 
be maintained in completely intimate contact during exposure. Accordingly, 
scattering, reflection, etc., caused by the presence of a cover sheet can 
be minimized. Thus, a marked improvement is brought about in the resolving 
power of images which is considered to be most defective in conventional 
peel developing methods. For example, according to the process of this 
invention, images with a line width of 15 .mu.m can be resolved without 
great difficulty. 
The useful aromatic diazonium compounds in this invention are represented 
by the general formula 
EQU ArN.sub.2.sup.+ X 
wherein N.sub.2 represents a diazonium group (--N.tbd.N.sup.+) and Ar 
represents an aromatic moiety known to those skilled in the art to be 
useful for forming stable photosensitive diazonium compounds. This moiety 
is well known to those skilled in the art, and described, for example, in 
Kosar, Light-Sensitive Systems, John Wiley & Sons, Inc., New York, N.Y. 
(1965), pages 202-214, and Glafkides, Photographic Chemistry, Vol. 11, 
Fountain Press, London, England (1960), pages 709-725. The stability here 
means that a compound is stable under nonactinic light, i.e., visible and 
near infrared light. 
The diazonium salts which can be used in this invention are classified by 
their structures and illustrated below. 
The above diazonium salts include compounds in which the Ar group of the 
above general formula represents an N-substituted-4-aminobenzenediazonium 
group, N,N-substituted-4-amino-substituted benzenediazonium group or 
S-substituted-4-mercaptobenzenediazonium group, and X represents an anion. 
The N-substituted amino group includes, for example, a dialkylamino group, 
a dialkylamino group with the two alkyl groups being different from each 
other (examples of alkyl groups are methyl, ethyl, isopropyl, etc.), a 
phenylamino group or a heterocyclic group such as a morpholino, 
piperidino, piperazinyl or pyrrolidinyl group. The benzene ring may be 
further substituted by an alkyl, alkoxy, phenoxy or trifluoromethyl group 
or a halogen atom. The substituted mercapto group may be an alkylthio or 
arylthio group (the alkyl groups being as defined for the alkylamino and 
examples of the aryl group including phenyl, tolyl, ethylphenyl, naphthyl, 
etc.). 
Examples of the anion (X) are those of a metal halide such as zinc chloride 
or stannic chloride, a boron compound such as tetrafluoroborate or 
tetraphenyl borate, perchloric acid, an organic acid such as 
p-toluenesulfonic acid, hexafluorophosphate, hexafluoroarsenate, and 
hexafluoroantimonate. They form double salts with the above diazonium 
compounds to contribute to the enhancement of their stability. 
Some of the diazonium salts of the general formula ArN.sub.2 X are 
specifically disclosed below, however, the present invention is not 
limited to the use of these specific compounds. 
Diazonium salts having a dialkylamino group introduced as an N-substituted 
amino group in the aforesaid residue include 
4-(N,N-diethylamino)benzenediazonium salt, 
4-(N,N-dimethylamino)benzenediazonium salt, 
2-methyl-4-(N,N-diethylamino)benzenediazonium salt, and 
2-chloro-4-(N,N-diethylamino)benzenediazonium salt. Diazonium salts having 
a dialkylamino group introduced as an N-substituted amino group in the 
aforesaid residue, the two alkyl groups being different from each other 
include 4-(N-methyl-N-ethylamino)benzenediazonium salt. Diazonium salts 
having a phenylamino group introduced as an N-substituted amino group in 
the aforesaid residue include 4-(N-ethyl-N-benzylamino)benzenediazonium 
salt, and 4-anilinobenzenediazonium salt. Diazonium salts having a 
heterocyclic group introduced as an N-substituted amino group in the 
aforesaid residue include 4-morpholinobenzenediazonium salt, 
2,5-dibutoxy-4-morpholinobenzenediazonium salt, 
2,5-diethoxy-4-morpholinobenzenediazonium salt, 
2,5-diethoxy-4-morpholinobenzenediazonium salt, and 
3-methyl-4-pyrrolidinylbenzenediazonium salt. Diazonium salts containing 
an S-substituted-4-mercapto groups include 
4-ethylmercapto-2,5-diethoxybenzenediazonium salt and 
4-tolylmercapto-2,5-diethoxybenzenediazonium salt. 
The diazonium salts used in the invention include polymers obtained by the 
polycondensation of diazodiphenylamine and formaldehyde. A specific 
example is a polymer having the following structure: 
##STR1## 
The diazonium salts also include ortho- or paraquinonediazides. Specific 
examples are as follows: 
Naphthalene-1,2-diazooxide-4-sulfonic acid; 
##STR2## 
wherein R.sub.1 is a hydrogen atom, an alkyl group (e.g., methyl, ethyl, 
propyl, isopropyl, etc.) or an aralkyl group (e.g., benzyl, phenethyl, 
etc.); and R.sub.2 is an aryl group (e.g., phenyl, tolyl, ethylphenyl, 
naphthyl, etc.); 
##STR3## 
wherein R.sub.3 is alkoxy (e.g., methoxy, ethoxy, propoxy, etc.), aryloxy 
(e.g., phenoxy, tolyloxy, etc.), alkylamino (e.g., methylamino, 
ethylamino, dimethylamino, diethylamino, etc.), aralkylamino (e.g., 
benzylamino, dibenzylamino, etc.) or carboxyalkoxyalkyl (e.g., 
carboxymethoxymethyl, etc.); 
##STR4## 
wherein X.sub.1 and X.sub.2 are N.sub.2 or O; Y is arylene (e.g., 
phenylene, naphthylene, etc.) or alkylene (e.g., methylene, ethylene, 
trimethylene, tetramethylene, etc.); Z is O or --NR.sub.4, R.sub.4 is 
hydrogen, alkyl (e.g., methyl, ethyl, propyl, isopropyl, etc.) or aryl 
(e.g., phenyl, tolyl, ethylphenyl, naphthyl, etc.). 
Especially useful diazonium salts for use in the process of this invention 
are those which have relatively high solubilities in organic solvents, and 
can be used in a relatively high concentration relative to the binder in 
forming an organic solvent solution of a photosensitive image-forming 
composition together with the binder, as will be described hereinbelow. 
Usually, two means are available to achieve such conditions. A first means 
is to render the diazonium cation of the formula ArN.sub.2.sup..sym. in 
the general formula ArN.sub.2.sup..sym..X.sup..crclbar. oleophilic or less 
hydrophilic by, for example, introducing an alkoxy group into an aromatic 
ring. A second means is to render the anionic portion X.sup..crclbar. 
oleophilic or less hydrophilic, and for this purpose, tetraphenyl borate, 
tetrafluoroborate, hexafluorophosphate, hexafluoroarsenate, 
p-toluenesulfonic acid and hexafluoroantimonate are used instead of metal 
halides which are usually employed. These compounds form double salts 
together with the diazonium cations to increase their solubility in 
organic solvents. 
As a result of rendering diazonium salts oleophilic, even when a polymer 
soluble in an organic solvent is used as a binder, the ratio of the 
diazonium salt to the binder can be increased to, for example, 1:5 or to 
1:1, and a high concentration of the photosensitive material can be 
obtained. Thus, the ease of image formation is markedly enhanced. 
Aromatic azide compounds which can be used in this invention are those of 
the general formula N.sub.3 --R.sub.5 --CH.dbd.CH-R.sub.6 in which R.sub.5 
represents a phenylene group, and R.sub.6 represents an acyl group (e.g., 
acetyl, benzoyl) or an azidearyl group. These compounds are known to those 
skilled in the art from, for example, Kosar, Light-Sensitive Systems, John 
Wiley & Sons, Inc., New York, N.Y. (1965), pp. 330-336. 
Also useful are azide compounds belonging to another group described at 
pages 93 to 97 of Takahiro Tsunoda, Photo-Sensitive Resins, Revised 
Edition, Publishing Department of the Society of Printing (1975), W. S. De 
Forest, Photoresist: Materials and Processes, pp. 19-62 (1975), 
McGraw-Hill Book Co., New York. Specifically, they include 
2,6-dichloro-4-nitroazidobenzene, azidodiphenylamine, 
3,3'-dimethoxy-4,4'-diazidodiphenyl, 4'-methoxy-4-azidodiphenylamine, 
4,4'-diazidodiphenylamine, 4,4'-diazidodiphenylmethane, 
4'-nitrophenylazobenzene-4-azide, 1-azidopyrene, 
3,3'-dimethyl-4,4'-diazidodiphenyl, 4,4'-diazidophenylazonaphthalene, 
p-phenylene bisazide, p-azidobenzophenone, 4,4'-diazidobenzophenone, 
4,4'-diazidochalcone, 2,6-di-(4'-azidobenzal)cyclohexane and 
2,6-di-(4'-azidobenzal)-4-methylcyclohexanone. 
The binder used in the photosensitive composition layer in this invention 
may be any which does not produce adhesiveness at ordinary temperatures 
but when heated, becomes softened. Various film-forming compounds are 
available, but polymers having good film-formability are especially 
useful. As will be illustrated below, one characteristic of the method of 
this invention is that a very broad range of polymeric compounds can be 
used. However, it is necessary to select a binder best suited for the 
particular purpose the photosensitive image-forming material is used; 
using as a guide a set of factors including the compatibility of the 
binder with the diazonium or aromatic azide compound used as a 
photosensitive compound, the stability of the photosensitive layer, the 
adhesion of the photosensitive layer to the support and other 
characteristics of the photosensitive material. 
Examples of suitable polymeric binders used in the invention include 
thermoplastic linear polymers such as polyvinyl butyral, polyvinyl formal, 
polystyrene, poly(methyl methacrylate), polyvinyl acetate, polyesters, 
polyamines, polyurethane and polyamides; binary copolymers such as a 
vinylidene/acrylonitrile copolymer, a styrene/acrylonitrile copolymer, a 
vinyl methyl ether/maleic anhydride copolymer, a vinyl acetate/maleic 
anhydride copolymer, a vinyl chloride/vinyl acetate copolymer or a vinyl 
chloride/styrene copolymer, and ternary or quaternary copolymers 
containing other third and fourth comonomers. Partially cross-linked 
water-soluble polymers such as gelatin, polyvinyl alcohol or polyvinyl 
pyrrolidone, and compounds which are not thermoplastic themselves, such as 
epoxy resins, can be used if they are improved by mixing with 
thermoplastic binders or other additives to substantially impart 
heat-softenability to the photosensitive composition layer. 
Polyethylene glycol, rosin, and waxes which have poor film-formability can 
be used as binders, but they should be used preferably with other 
polymeric binders to increase the heat-softenability to the photosensitive 
composition layer. These polymeric substances can be coated on a support 
as dispersed in an aqueous or organic solvent as a latex. 
Examples of thermoplastic polymers which are particularly suitable for the 
binder used in the photosensitive composition of this invention include 
vinylidene chloride, a vinylidene chloride/acrylonitrile copolymer, 
polyvinyl butyral and the like. When the adhesive force of the binder to 
the peeling development carrier sheet at the peeling development treatment 
temperature employed is too weak, a good result could be obtained by 
further providing on the photosensitive composition layer a material which 
is thermoplastic at a relatively low temperature and exhibits tackiness or 
stackness, e.g., polyvinyl butyral. 
Furthermore, polyvinyl alcohol which is a hydrophilic binder can be 
advantageously used when the photosensitive substance used is hydrophilic. 
In such a case, a hydrophobic polymer can be used for coating in a latex 
form. 
Plasticizers which are liquid or viscous at room temperature can be added 
in amounts do not impair the shape of the photosensitive composition 
layer. 
The peel development effect in accordance with this invention can also be 
enhanced by adding organic or inorganic fine powders such as colloidal 
silica, starch, carbon black, glass powders and metal powders. 
According to the purpose of use of the relief images obtained after peeling 
development, the photosensitive composition layer may also contain 
pigments or dyes, fine metal powders, and magnetic materials or 
fluorescent substances in the form of molecularly dispersed state or as 
crystals or fine powders. 
The thickness of the photosensitive composition layer is generally from 0.5 
.mu.m to 500 .mu.m, preferably from 1 .mu.m to 100 .mu.m. 
The support used to support the photosensitive composition in the process 
of this invention may be any flat materials, for example, metals such as 
aluminum, steel, zinc, iron, stainless steel, and brass and hard 
non-flexible materials such as glass, ceramics, wood or plastics, and 
flexible materials such as paper, plastic films, fibrous materials, and 
vacuum-deposited films. The surfaces of these supports may be further 
processed by coating, vacuum deposition, lamination, polishing, 
roughening, electrode reaction, discharging, heating, and other known 
means. 
The support may be transparent, non-transparent or colored with dyes or 
pigments depending on whether the resulting photosensitive material is 
used as a transparent visible image, a reflective image, a printing 
plate-making material, etc. 
There is no particular restriction on the thickness or configuration of the 
support. In the case of a film or sheet, its thickness generally ranges 
from about 10 .mu.m to several cm. Those having thicknesses outside this 
range can also be used if they permit coating and bonding, and peeling at 
the time of heating. 
The adhesive composition used on the carrier sheet used in this invention 
can be a composition which contains a polymeric material and a tackifier 
as essential ingredients. The polymeric material includes a synthetic 
rubber, a cellulosic polymeric material or a vinyl-type polymer. Examples 
of the rubber are natural rubber, butadiene-styrene rubber, 
isobutylene-isoprene rubber, polychloroprene, polybutylene, polybutadiene, 
polyisoprene, butadiene-acrylonitrile rubber, chlorinated rubbers, and 
silicone rubbers. Examples of the cellulosic polymer are ethyl cellulose, 
butyl cellulose, benzyl cellulose, nitrocellulose, cellulose diacetate, 
cellulose, propionate, cellulose acetate propionate, and cellulose acetate 
butyrate. Examples of the vinyl-type polymer include polyvinyl chloride, 
polyacrylic acid, poly(methyl acrylate), poly(ethyl acrylate), poly(butyl 
acrylate), polymethacrylate acid, poly(methyl methacrylate), polyvinyl 
ether, polyvinyl acetal, and copolymers of these. 
Specific examples of the tackifier include gum rosin, wood rosin, 
hydrogenated rosin, methyl abietate, hydrogenated methyl abietate, 
diethylene glycol abietate, diethylene glycol 2-hydroabietate, a 
monoethylene glycol ester of rosin, a pentaerythritol ester of rosin, a 
glycerin ester of rosin, a methanol ester or rosin, hydrogenation products 
of these rosin esters, coumarone-indene resin, alkyd resins, terpene 
resins (e.g., poly(1,8-menthadiene)), xylene resins, epoxy resins, 
terpene-phenol resins, polybutene, polypentene, dammer, copal, animal oils 
and fats, vegetable oils and fats, and mineral oils. 
When the rubber polymer or vinyl-type polymer is used, a plasticizer must 
be jointly incorporated in the adhesive composition. Examples of the 
plasticizer are dimethyl phthalate, diethyl phthalate, dibutyl phthalate, 
dioctyl phthalate, dicyclohexyl phthalate, dimethyl glycol phthalate, 
butyl phthallyl butyl glycolate, triethylene glycol, chlorinated diphenyl, 
diisobutyl adipate, and dimethyl sebacate. 
If required, the adhesive composition may further contain antioxidants, 
coloring agents and inorganic or organic fillers. Generally, the adhesive 
composition is dissolved in a solvent typified by an aromatic hydrocarbon 
such as benzene, toluene, ethylbenzene or xylene, an aliphatic hydrocarbon 
such as pentane, cyclohexane, octane or methylcyclohexane, an ether such 
as methyl ether, ethyl ether or tetrahydrofuran, or a halogenated 
hydrocarbon such as chloroform, carbon tetrachloride, dichloromethane, 
dichloroethane or chlorobenzene. The solution is coated on a carrier sheet 
and dried in a known manner. The thickness of the adhesive composition 
layer after removal of the solvent is generally from 0.5 .mu.m to 50 
.mu.m, preferably from 1 .mu.m to 20 .mu.m. 
Examples of carrier sheet which can be most easily used are commercially 
available pressure-sensitive adhesive tapes or sheets, paper tapes or 
sheets, cloth tapes, polyester tapes or sheets, and polyvinyl chloride 
tapes or sheets. 
As is clear from the foregoing description, for image formation by peeling, 
the materials and constructions of the support, photosensitive layer, and 
peel developing sheet, and the combination of these are very important. 
The developing conditions cannot be simply defined, however, they can be 
determined easily by the artisan without undue experimentation. Generally, 
however, the temperature at which a sheet having an adhesive composition 
layer is laminated is from ordinary temperature to 150.degree. C., 
preferably from ordinary temperature to 100.degree. C. 
The peel developing sheet and the photosensitive image-forming material 
which have thus been heat-laminated are separated from each other by a 
peeling operation. The temperature at the time of peeling is also very 
important. 
Generally, if the peeling temperature is higher than the softening 
temperature of the phososensitive composition layer, cohesive destruction 
of the photosensitive composition layer occurs whereby a part of the area 
of the photosensitive layer which is to be separated by peeling 
development adheres to the supporting carrier, and a part of the area 
which is to remain adheres to the peel developing sheet. Thus, the 
resulting relief image tends to be incomplete. When the peeling 
temperature is higher than the softening temperature of the adhesive 
surface of the peel developing sheet having an adhesive layer, the 
adhesive layer breaks or undergoes cohesive destruction. Hence, good 
quality relief images cannot be obtained. 
Of course, the adhesion strength between the photosensitive composition 
layer and the support carrier affects the formation of relief images by 
peeling. 
The peeling temperature which is optimal for the process of this invention 
also varies widely according to the combination of the supporting carrier, 
the photosensitive composition layer and the adhesive layer of the peel 
developing sheet. Generally, the peeling temperature is from room 
temperature to 100.degree. C., preferably from room temperature to 
60.degree. C. 
Embodiments of the construction of the photosensitive image-forming 
material used in the invention and the process for image formation in 
accordance with this invention are described by reference to the 
accompanying drawings in which FIGS. 1 to 3 illustrate one embodiment of 
the image-forming process in accordance with this invention. 
FIG. 1 illustrates exposure of the photosensitive image-forming material in 
accordance with this invention through a transparency. The photosensitive 
image-forming material comprising a support 1 and a photosensitive layer 2 
is imagewise exposed through an original image transparency 3. 
FIG. 2 illustrates the exposed image-forming material in intimate contact 
with the peeling development carrier sheet 5 having an adhesive layer 4. 
FIG. 3 shows separation of the peeling development carrier sheet from the 
image-forming material. The exposed area 2' of the photosensitive layer is 
transferred and adhered to the peeling development carrier sheet, and the 
unexposed area 2 remains on the support, respectively forming a relief 
image. 
The following Examples illustrate the present invention more specifically. 
It should be understood, however, that these Examples do not in any way 
limit the scope of the invention. 
EXAMPLE 1 
2 g of a 4-morpholinobenzenediazonium/boron tetrafluoride double salt and 2 
g of a vinylidene chloride/acrylonitrile copolymer (Saran F-220, a product 
of Asahi Dow Co., Ltd.) were dissolved in 20 ml of N,N-dimethylformamide 
to form a photosensitive solution. The photosensitive solution was coated 
on a grained and anodized aluminum substrate having a thickness of 0.24 
.mu.m using a whirler to form a photosensitive image-forming material. The 
dry thickness of the photosensitive layer was about 4 .mu.m. The material 
was exposed for 20 seconds to light from a 2 kw superhigh mercury lamp 
(Jet Light, a product of Orc Manufacturing Co., Ltd.) disposed at a 
distance of 50 cm through a photographic positive transparency contacted 
intimately with the material. After exposure, an adhesive tape of 
polyethylene terephthalate having thereon a layer of an adhesive 
composition (the tape being 31B, a product of Nitto Denko Co., Ltd.) was 
press-bonded closely to the photosensitive composition layer using 
rollers, and then at room temperature, the two elements were separated 
from each other. A positive relief image of good quality was formed on the 
aluminum plate, and the corresponding negative relief image was formed on 
the peeled adhesive sheet. 
EXAMPLE 2 
The procedure of Example 1 was repeated except that 2 g of an m-cresol-type 
novolak resin (PR 50904, a product of Arakawa Rinsan Co., Ltd.) was used 
as a binder instead of the Saran used in Example 1. A positive image of 
good quality was formed on the aluminum substrate. 
EXAMPLE 3 
The procedure of Example 1 was repeated except that 2 g of the condensation 
product of 4-N-phenylaminobenzenediazonium and formaldehyde (the degree of 
polymerization 2 to 8) was used instead of the diazonium compound used in 
Example 1. A positive image of good quality was formed on the aluminum 
substrate, and a corresponding negative image was formed on the adhesive 
tape. 
EXAMPLE 4 
The procedure of Example 1 was repeated except that 1 g of 
4-N,N-dimethylaminobenzenediazonium/tetraphenylboron double salt was used 
instead of the diazonium compound used in Example 1. A positive image of 
good quality was formed on the aluminum substrate. 
EXAMPLE 5 
The procedure of Example 1 was repeated except that 1 g of 
2,6-di(4'-azidobenzal)-4-methylcyclohexane was used instead of the 
diazonium compound used in Example 1. A positive image of good quality was 
formed on the aluminum substrate. 
EXAMPLE 6 
The procedure of Example 1 was repeated except that 0.5 g of 
1-diazo-2,5-dimethoxy-1-p-tolylmercaptobenzene phosphorus hexafluoride 
double salt was used instead of the diazonium compound used in Example 1. 
A positive image of good quality was obtained on the aluminum substrate. 
EXAMPLE 7 
The procedure of Example 1 was repeated except that 2 g of 
2-diazo-1-naphthol-5-sulfonic acid ethyl ether was used instead of the 
diazonium compound used in Example 1. A positive image of good quality was 
obtained on the aluminum substrate. 
EXAMPLE 8 
The procedure of Example 1 was repeated except a substrate composed of 
polyethylene terephthalate having aluminum vacuum-deposited thereon in a 
thickness of about 1,000 A was used instead of the support used in Example 
1. A positive relief image of good quality was obtained on the aluminum 
layer. 
EXAMPLE 9 
The procedure of Example 1 was repeated except that a support composed of a 
polyethylene terephthalate film and a subbing layer of gelatin was used 
instead of the aluminum plate used in Example 1. A positive relief image 
of good quality was obtained on the support. 
EXAMPLE 10 
The procedure of Example 1 was repeated except that a support composed of 
an aluminum substrate and a 1.mu. thick layer of polyvinyl alcohol formed 
on it was used instead of the aluminum substrate used in Example 1. A 
positive relief image of good quality was obtained on the support. 
EXAMPLE 11 
2 g of a 4-morpholino-2,5-dibutoxybenzene diazonium/boron tetrafluoride 
double salt and 2 g of polyvinyl butyral were dissolved in 40 ml of ethyl 
alcohol to form a photosensitive solution. The solution was coated on an 
aluminum substrate which had been grained, anodized and treated with 
sodium silicate to obtain a photosensitive image-forming material. The 
image-forming material was imagewise exposed as in Example 1, and then 
brought into intimate contact under heat with an adhesive film (31E, a 
product of Nitto Denko, Co., Ltd.) comprising a polyethylene terephthalate 
film and an adhesive composition layer formed thereon by means of a heat 
laminator (Fuji Laminater D-13, a product of Fuji Photo Film Co., Ltd.) in 
which the roller temperature was maintained at 80.degree. C. The two 
elements were then peeled from each other. A positive relief image of good 
quality was obtained on the aluminum substrate. 
While the invention has been described in detail and with reference to 
specific embodiments thereof, it will be apparent to one skilled in the 
art that various changes and modifications can be made therein without 
departing from the spirit and scope thereof.