Water soluble photosensitive resin composition comprising a polyamide or its ammonium salt

A photosensitive resin composition which comprises a polymer having a basic nitrogen atom in the main or side chain, which is represented by the formula: ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 are each a hydrogen atom or a substituted or unsubstituted hydrocarbon group, at least one of R.sub.1 to R.sub.3 representing a polymeric chain, a photopolymerizable unsaturated monomer and a photosensitizer.

The present invention relates to a photosensitive resin composition. 
It is known that a relief printing plate can be prepared by exposing a 
photosensitive material comprising a layer of a photosensitive resin 
composition (hereinafter referred to as "photosensitive layer") and a 
support therefor through a negative or positive film having a transparent 
image to an active light so as to cure and make insoluble the 
photosensitive resin composition at the exposed part and then removing off 
the photosensitive resin composition at the non-exposed part with a 
suitable solvent. Such photosensitive resin composition comprises usually 
a photocopolymerizable unsaturated monomer, a polymer which is soluble in 
a suitable solvent and, when photopolymerized with the said monomer, 
becomes insoluble, a photosensitizer and a thermal polymerization 
inhibitor. Namely, the said photosensitive resin composition, especially 
the said polymer, should be soluble in a suitable solvent before exposure 
but becomes insoluble in the same solvent after exposure. Further, the 
said polymer should show a large mechanical strength and not be swollen by 
organic solvents after photopolymerization with the photopolymerizable 
unsaturated monomer. As such polymer, there have been proposed some 
copolymerized polyamides, which are soluble in alcohols (cf. Japanese 
patent publications Nos. 14719/1960, 15513/1960 and 7330/1970). These 
known polyamides are good in mechanical strength and resistance to 
solvents after photopolymerization but their solubility to solvents before 
photopolymerization is considerably lowered. Therefore, it takes a 
relatively long time to remove the photosensitive resin composition 
comprising such polyamide at the non-exposed part by washing in order to 
obtain a relief printing plate having an image of distinct contour. In 
addition, the use of large amounts of alcohols as the solvents causes 
various troubles on storage, handling, discard and the like. 
As the result of extensive studies, there has now been provided a 
photosensitive resin composition which is readily dissolved in water or a 
dilute aqueous acid before photopolymerization and which becomes insoluble 
therein showing an excellent mechanical strength after 
photopolymerization. 
The photosensitive resin composition of the present invention comprises a 
polymer having a basic nitrogen atom in the main or side chain, a 
photopolymerizable unsaturated monomer and a photosensitizer. 
The polymer having a basic nitrogen atom in the main or side chain to be 
used in the invention is representable by the formula: 
##STR2## 
wherein R.sub.1, R.sub.2 and R.sub.3 are each a hydrogen atom or a 
substituted or unsubstituted hydrocarbon group, at least one of R.sub.1 to 
R.sub.3 representing a polymeric chain. 
The polymer (A) may be a polyamide (A-1) or a vinyl polymer (A-2), which 
has a basic nitrogen atom in the main or side chain. 
The polyamide (A-1), which has a basic nitrogen atom in the main chain, may 
be prepared, for instance, by the use of at least one of the compounds 
represented by either one of the formulae: 
##STR3## 
wherein R and R' are each a hydrogen atom or a hydrocarbon group 
(preferably having 1 to 10 carbon atoms), R.sub.1.sup.a, R.sub.2.sup.a and 
R.sub.3.sup.a are each an alkylene group (preferably having 1 to 15 carbon 
atoms) and A and B are each --NH.sub.2, --COOH or --COOR" (R" being a 
hydrocarbon group (preferably having 1 to 10 carbon atoms)) as the 
starting monomer. Still, the group of the formula: --R.sub.2.sup.a --B in 
the monomer (I) may represent a hydrogen atom. 
As the monomer (I), there may be exemplified diamines (e.g., 
N-(2-aminoethyl)piperazine, N-(2-aminopropyl)piperazine, 
N-(6-aminohexyl)piperazine, N-(4-aminocyclohexyl)piperazine, 
N-(2-aminoethyl)-3-methylpiperazine, 
N-(2-aminoethyl)-2,5-dimethylpiperazine, 
N-(2-aminopropyl)-3-methylpiperazine, 
N-(3-aminopropyl)-2,5-dimethylpiperazine, N,N'-bis(aminomethyl)piperazine, 
N,N'-bis(2-aminoethyl)piperazine, N,N'-bis(2-aminoethyl)methylpiperazine, 
N-(aminomethyl)-N'-(2-aminoethyl)piperazine, 
N,N'-bis(3-aminopentyl)piperazine), dicarboxylic acids (e.g. 
N,N'-bis(carboxymethyl)piperazine, 
N,N'-bis(carboxymethyl)methylpiperazine, N,N'-bis(carboxymethyl)-2,6-dimet 
hylpiperazine, N,N'-bis(2-carboxyethyl)piperazine, 
N,N'-bis(3-carboxypropyl)piperazine, 
N-(2-carboxyethyl)-N'-(carboxymethyl)piperazine) and their reactive 
derivatives such as the lower alkyl esters and acid halides thereof, 
.omega.-amino acids (e.g. N-carboxymethylpiperazine, 
N-(2-carboxyethyl)piperazine, N-(3-carboxypropyl)piperazine, 
N-(6-carboxyhexyl)piperazine, N-(4-carboxycyclohexyl)piperazine, 
N-(2-carboxyethyl)-3-methylpiperazine, 
N-(2-carboxyethyl)-2,5-dimethylpiperazine, 
N-(aminomethyl)-N'-(carboxymethyl)piperazine, 
N-(aminomethyl-N'-(2-carboxyethyl)piperazine, 
N-(2-aminoethyl)-N'-(2-carboxyethyl)piperazine, 
N-(aminomethyl)-N'-(carboxymethyl)-2-methylpiperazine), etc. 
As the monomer (II), there may be exemplified diamines (e.g. 
N,N'-bis(2-aminoethyl)cyclohexylamine, N,N-bis(3-aminopropyl)amine, 
N,N-bis(2-aminoethyl)methylamine, N,N-bis(3-aminopropyl)ethylamine, 
N,N-bis(3-aminopropyl)isopropylamine, 
N,N-bis(3-aminopropyl)cyclohexylamine, N,N-bis(4-amino-n-butyl)amine, 
N-(2-aminoethyl)-N-methyl-1,3-propanediamine), dicarboxylic acids (e.g. 
N,N-bis(carboxymethyl)methylamine, N,N-bis(2-carboxyethyl)ethylamine, 
N,N-bis(2-carboxyethyl)methylamine, N,N-bis(2-carboxyethyl)isopropylamine, 
N-carboxymethyl-N-(2-carboxyethyl)methylamine) and their reactive 
derivatives such as the lower alkyl esters and acid halides thereof, 
.omega.-amino acids (e.g., N-(aminomethyl)-N-(carboxymethyl)methylamine, 
N-(2-aminoethyl)-N-(2-carboxyethyl)methylamine, 
N-(aminomethyl)-N-(2-carboxyethyl)isopropylamine, 
N-(3-aminopropyl)-N-(3-carboxypropyl)methylamine, 
N-(3-aminopropyl)-N-(2-carboxyethyl)methylamine), etc. 
As the monomer (III), there may be exemplified diamines (e.g., 
N,N'-dimethyl-N,N'-bis(3-aminopropyl)ethylenediamine, 
N,N'-dimethyl-N,N'-bis(3-aminopropyl)tetramethylenediamine, 
N,N'-diisobutyl-N,N'-bis(3-aminopropyl)hexamethylenediamine, 
N,N'-dicyclohexyl-N,N'-bis(3-aminopropyl)hexamethylenediamine, 
N,N'-diethyl-N,N'-bis(3-aminopropyl)-2,2,4-trimethylhexamethylenediamine), 
dicarboxylic acids (e.g. 
N,N'-dimethyl-N,N'-bis(carboxymethyl)ethylenediamine, 
N,N'-dimethyl-N,N'-bis(2-carboxyethyl)ethylenediamine, 
N,N'-dimethyl-N,N'-bis(3-carboxypropyl)hexamethylenediamine) and their 
reactive derivatives such as the lower alkyl esters and acid halides 
thereof, .omega.-amino acids (e.g., 
N,N'-dimethyl-N-(aminomethyl)-N'-(carboxymethyl)ethylenediamine, 
N,N'-dimethyl-N-(2-aminoethyl)-N'-(2-carboxyethyl)ethylenediamine, 
N,N'-dimethyl-N-(aminomethyl)-N'-(2-carboxyethyl)hexamethylenediamine, 
etc. 
The polyamide (A-1), which has a basic nitrogen atom in the side chain, may 
be prepared, for instance, by the use of at least one of the compounds 
represented by the formula: 
##STR4## 
wherein R.sub.4.sup.a and R.sub.5.sup.a are each a hydrocarbon group 
(preferably having 1 to 10 carbon atoms) or they may be linked together to 
form a ring, R.sub.6.sup.a is a lower alkyl group (preferably having 1 to 
3 carbon atoms or a group of the formula: 
##STR5## 
(wherein R.sub.4.sup.a and R.sub.5.sup.a are each as defined above) and Y 
is a .gamma.-aminopropyl group as the starting monomer. 
As the monomer (IV), there may be exemplified diamines (e.g. 
6-methyl-6-(N,N-dimethylaminomethyl)-4,8-dioxaundecanediamine, 
6-methyl-6-(N,N-diethylaminomethyl)-4,8-dioxaundecanediamine, 
6-ethyl-6-(N,N-dimethylaminomethyl)-4,8-dioxaundecanediamine, 
8,6-bis(N,N-dimethylaminomethyl)-4,8-dioxaundecanediamine), etc. 
These monomers may be used solely or in combination. 
In addition to the monomers (I) to (IV), aliphatic and/or aromatic 
dicarboxylic acids, diamines, .omega.-amino acids and lactams as usually 
employed for the preparation of polyamides may be also used as the 
monomeric components in production of the polyamide (A-1). 
Examples of the dicarboxylic acids are aliphatic and/or aromatic 
dicarboxylic acids (e.g., succinic acid, adipic acid, glutaric acid, 
azelaic acid, sebacic acid, dodecanedicarboxylic acid, terephthalic acid, 
isophthalic acid, cyclohexanedicarboxylic acid), etc. Their reactive 
derivatives such as the lower alkyl esters and acid halides thereof are 
also utilizable. Examples of the diamines are saturated aliphatic diamines 
having a straight chain (e.g., tetramethylenediamine, 
pentamethylenediamine, hexamethylenediamine, heptamethylenediamine, 
octamethylenediamine, nonamethylenediamine, decamethylenediamine), 
aromatic diamines (e.g., metaxylylenediamine, paraxylylenediamine), 
alicyclic diamines (e.g., cyclohexanebismethylamine), etc. Examples of the 
.omega.-amino acids are aminocaproic acid, aminoheptanoic acid, 
aminocaprylic acid, aminocapric acid, aminolauric acid, etc. Examples of 
the lactams are .epsilon.-caprolactam, 
.alpha.-methyl-.epsilon.-caprolactam, 
.epsilon.-methyl-.epsilon.-caprolactam, cyclopeptanoneisoxime, 
cyclooctanoneisoxime, etc. 
The polyamide (A-1) may be prepared by conventional polymerization 
procedures. The amount of the monomeric component containing a basic 
nitrogen atom such as the monomers (V) to (IV) may be usually 10 to 100 
mol %, preferably 20 to 50 mol %, of the total amount of the monomeric 
components of the polyamide. 
The vinyl polymer (A-2), which has a basic nitrogen atom in the main or 
side chain, may be prepared, for instance, by the use of at least one of 
the compounds represented by the formula: 
##STR6## 
wherein R.sub.1.sup.b is a hydrogen atom or a hydrocarbon group 
(preferably having 1 to 10 carbon atoms, R.sub.2.sup.b is an alkylene 
group (preferably having 1 to 15 carbon atoms), R.sub.3.sup.b and 
R.sub.4.sup.b are each a hydrocarbon group (preferably having 1 to 10 
carbon atoms) and Q is an ester linkage or an amide linkage as the 
starting monomer. 
Examples of the monomer (V) are acrylates and methacrylates (e.g., 
2-(N,N-dimethylamino)ethyl acrylate, 2-(N,N-dimethylamino)ethyl 
methacrylate, 2-(N,N-diethylamino)ethyl acrylate, 
2-(N,N-diethylamino)ethyl methacrylate, 2-(N,N-dibutylamino)ethyl 
acrylate, 2-(N,N-dibutylamino)ethyl methacrylate, 
3-(N,N-diethylamino)propyl acrylate, 3-(N,N-diethylamino)propyl 
methacrylate), acrylamides and methacrylamides (e.g. 
3-(N,N-dimethylamino)propyl acrylate, 3-(N,N-dimethylamino)propyl 
methacrylate, 3-(N,N-diethylamino)propyl acrylate, 
3-(N,N-diethylamino)propyl methacrylate), etc. 
These monomers may be used solely or in combination. 
In addition to the monomer (V), any vinyl monomer which is conventionally 
employed in the production of vinyl polymers may be used. 
Examples of such vinyl monomer are styrene, vinyl chloride, vinylidene 
chloride, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, 
methyl acrylate, methyl methacrylate, vinyl acetate, N-vinylpyrrolidone, 
methyl vinyl ketone, ethylene, propylene, acrylic acid, methacrylic acid, 
etc. 
The vinyl polymer (A-2) may be prepared by conventional polymerization 
procedures. The amount of the monomeric component containing a basic 
nitrogen atom such as the monomer (V) may be usually 10 to 100 mol %, 
preferably 20 to 50 mol %, of the total amount of the monomeric components 
of the vinyl polymer. 
The polymer (A) as above prepared may be used as such or in an ammonium 
salt form in the photosensitive resin composition of the invention. 
For conversion of the polymer (A) into its ammonium salt form, the former 
may be treated with a protonic acid, a quaternizing agent or a protonic 
acid and an epoxy compound. The treatment may be effected, for instance, 
by dissolving the polymer (A) together with a protonic acid, a 
quaternizing agent or a protonic acid and an epoxy compound (preferably an 
unsaturated epoxy compound) in a suitable solvent at an appropriate 
temperature, by melting a mixture of the polymer (A) together with the 
said reagent(s), or by contacting the polymer (A) with the said reagent(s) 
in a gaseous state. Alternatively, such treatment may be carried out on or 
after admixing the polymer (A) with a photopolymerizable unsaturated 
monomer, a photosensitizer and/or a thermal polymerization inhibitor. 
The resulting polymer in ammonium salt form is representable by the 
formula: 
##STR7## 
wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are each a hydrogen atom or 
a substituted or unsubstituted hydrocarbon group, at least one of R.sub.1 
to R.sub.4 representing a polymeric chain, and X is an anion to be paired 
with the ammonium ion. 
As the protonic acid, there may be used an inorganic acid (e.g., 
hydrochloric acid, sulfuric acid) or an organic acid (e.g., formic acid, 
acetic acid, chloroacetic acid, maleic acid, phthalic acid, adipic acid, 
acrylic acid). Among them, the one containing a polymerizable unsaturated 
bond in its molecule such as acrylic acid, maleic acid or cinnamic acid 
can also serve as a cross linking agent to promote the curing. 
As the quaternizing agent, there may be exemplified alkyl halides (e.g., 
methyl chloride, ethyl chloride, methyl bromide, methyl iodide, ethyl 
chloride, ethyl bromide, lauryl chloride), aralkyl halides (e.g., benzyl 
chloride), 1,2-dichloroxylene, 1,3-dichloroxylene, ethylenechlorohydrin, 
2-chloroethyl acrylate, 2-chloroethyl methacrylate, 2,3-dibromopropyl 
acrylate, 2,3-dibromopropyl methacrylate, 3-chloro-2-hydroxypropyl 
acrylate, 3-chloro-2-hydroxypropyl methacrylate, dialkyl sulfates, alkyl 
p-toluenesulfonates, etc. 
As the epoxy compound, there may be preferably used the unsaturated one 
represented by the formula: 
##STR8## 
wherein R'" is a hydrogen atom or a lower alkyl group, Y' is --OOC--, 
--HNCO--, --O--, --SO.sub.3 -- or --HNCONH--, n is an integer of 0 to 3 
and m is 0 or 1. Specific examples are glycidyl acrylate, glycidyl 
methacrylate, N-glycidyl acrylamide, N-glycidyl methacrylamide, vinyl 
glycidyl ether, allyl glycidyl ether, glycidyl vinylsulfonate, 
N-isopropenylglycidylurethane, etc. The amount of the epoxy compound may 
be 0.02 to 10 mol, preferably 0.05 to 5 mol, to 1 mol of the basic 
nitrogen atom in the polymer (A). 
The amounts of the protonic acid and the quaternizing agent may be 
appropriately decided depending on the amount of the basic nitrogen atom 
in the polymer (A), the solubility of the resultant polymer (B) and the 
like. 
The thus obtained polymer (B) contains a nitrogen atom in ammonium salt 
form in the main or side chain and is readily soluble to water or a dilute 
aqueous acid. In particular, a large solubility to water is obtained when 
at least 1 .times. 10.sup.-3 mol of the nitrogen atom in ammonium salt 
form is present in 1 g of the polymer (B). 
As the photopolymerizable unsaturated monomer to be used in the 
photosensitive resin composition of the invention, there may be 
exemplified monomers containing one double bond (e.g., acrylic acid, 
methacrylic acid, methyl acrylate, methyl methacrylate, benzyl acrylate, 
tribromophenyl acrylate, cyclohexyl acrylate, 2-hydroxypropyl acrylate, 
acrylamide, methacrylamide, N-methylolacrylamide, 
n-butoxymethylacrylamide, isobutoxymethylacrylamide, 
N-tert-butylacrylamide, sodium acrylate, ammonium acrylate, acrylonitrile, 
styrene, sodium styrenesulfonate, vinyl pyridine) and monomers containing 
two or more double bonds (e.g., glycidyl methacrylate, allyl methacrylate, 
ethylene glycol diacrylate, ethylene glycol dimethacrylate, 
1,3-propanediol diacrylate, 1,3-propanediol dimethylacrylate, 
1,4-butanediol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol 
diacrylate, 1,6-hexanediol dimethacrylate, trimethylol propane 
triacrylate, trimethylolpropane trimethacrylate, tetramethylolmethane 
triacrylate, triacryloyloxyethyl phosphate, methylenebisacrylamide, 
ethylenebisacrylamide, propylenebisacrylamide, butylenebisacrylamide, 
methylenebismethacrylamide, ethylenebismethacrylamide, 
propylenebismethacrylamide). These monomers show a good compatibility with 
the said polymer (A) or (B) and may be used solely or in combination. The 
sole use of the monomer having at least two double bonds or the combined 
use of the monomers having at least one double bond is particularly 
favorable. 
The amount of the monomer may be 5 to 150% by weight, preferably 10 to 100% 
by weight, to the polymer (A) or (B) in the photosensitive resin 
composition. When the amount is smaller than 5% by weight, the 
insolubility at the exposed part is insufficient. When the amount is 
larger than 150% by weight, the mechanical strength of the photosensitive 
layer after exposure is deteriorated. 
As the photosensitizer, there may be employed any one which can promote the 
polymerization of the said monomer within the matrix of the polymer. 
Specific examples are anthraquinones (e.g., 9,10-anthraquinone, 1-chloro 
anthraquinone, 2-chloroanthraquinone), benzophenones (e.g., benzophenone, 
p-aminobenzophenone, p-chlorobenzophenone), benzoins (e.g., benzoin, 
benzoin methyl ether, benzoin ethyl ether, .alpha.-methylbenzoin), 
benzyls, etc. The amount of the photosensitizer may be 0.01 to 5% by 
weight, preferably 0.1 to 2% by weight, to the total amount of the polymer 
(A) or (B) and the photopolymerizable unsaturated monomer. 
The photosensitive resin composition can be prepared by admixing uniformly 
the polymer (A) or (B), the photopolymerizable unsaturated monomer and the 
photosensitizer, or by admixing uniformly the polymer (A), the protonic 
acid, the quaternizing agent or the protonic acid and the epoxy compound, 
the photopolymerizable unsaturated monomer and the photosensitizer. The 
admixing may be effected, for instance, by dissolving the materials in a 
suitable solvent (e.g., water, methanol, ethanol, isopropanol, chloroform, 
carbon tetrachloride, toluene, xylene) and removing the solvent by 
evaporation, or by mixing the materials in a melted state under such 
conditions as not to cause thermal polymerization of the resultant 
photosensitive resin composition to make the same insoluble. 
In addition to the said components, there may be incorporated any thermal 
polymerization inhibitor into the photosensitive resin composition. 
As the thermal polymerization inhibitor, there may be employed any one 
which can prevent thermal polymerization of the photopolymerizable 
unsaturated monomer during preparation, molding or processing of the 
photosensitive resin composition under heating or dark reaction of the 
photosensitive resin composition on storage. Specific examples are 
hydroquinones (e.g., hydroquinone, mono-tert-butylhydroquinone, 
2,5-di-tert-butylhydroquinone), benzoquinones (e.g., benzoquinone, 
2,5-di-tert-butyl-p-benzoquinone), catechols (e.g., catechol, 
p-tert-butylcatechol), picric acid, etc. The amount of the thermal 
polymerization inhibitor may be 0 to 2% by weight, preferably 0.05 to 0.5% 
by weight, to the total amount of the polymer (A) or (B) and the 
photopolymerizable unsaturated monomer. 
The photosensitive resin composition of the invention is readily soluble in 
mere water or a dilute aqueous acid. The time required for complete 
dissolution is equal to or shorter than that in the case of dissolving any 
polymer containing no nitrogen atom in the main or side chain in an 
aqueous alkali. 
When the photosensitive resin composition of the invention is irradiated 
with active lights from various light sources such as an ultrahigh 
pressure mercury lamp, high pressure mercury lamp, low pressure mercury 
lamp, xenon lamp and carbon arc lamp, the photochemical reaction of the 
photopolymerizable unsaturated monomer progresses within the matrix of the 
polymer to make the said composition insoluble in water or a dilute 
aqueous acid. The photosensitive resin composition thus irradiated with 
lights is hardly influenced by atmospheric moisture or by contact with 
hydrous substances and is excellent in physical strength. 
The photosensitive resin composition of the invention may be employed as a 
photosensitive material in a simple sheet form or in a layer form with a 
support. The preparation of a sheet may be effected, for example, by 
molding the photosensitive resin composition by heat pressing, casting or 
melt extrusion to obtain a desired thickness. A laminated product may be 
prepared, for example, by sticking the photosensitive resin composition in 
a sheet form on a support with or without an adhesive. As the support, 
there may be used any suitable one such as steel, aluminum, iron, glass or 
plastic film. 
For exposure, the photosensitive layer of the photosensitive material is 
closely contacted with a negative or positive film having a transparent 
image and subjected to irradiation with an active light. The thus 
irradiated material is immersed into water or a dilute aqueous acid to 
remove the non-exposed part off and dried, whereby a relief printing plate 
having an image with a distinct contour can be obtained. 
The photosensitive material can be advantageously utilized not only as 
printing materials but also in various fields of industries such as 
printing, decoration, construction materials and electric parts. 
Practical and presently preferred embodiments of the invention are 
illustratively shown in the following Examples wherein parts and % are by 
weight unless otherwise indicated. The reduced viscosity is determined at 
30.degree. C. with a polymer concentration of 400 mg/100 ml in a mixture 
of phenol and tetrachloroethane (6:4). The degree of gelation is 
determined by extracting the specimen after exposure with methanol by the 
aid of a Soxhlet's extractor for 24 hours, weighing the specimen after the 
extraction and making the calculation according to the following equation:

EXAMPLE 1 
In a reactor, N,N'-bis(.gamma.-aminopropyl)piperazine adipate (40 parts), 
.epsilon.-caprolactam (60 parts), water (50 parts) and n-butylamine (0.3 
part) are charged, and after sufficient replacement of the atmosphere by 
nitrogen, the reactor is sealed. The temperature is gradually elevated. 
The inner pressure reaches 10 kg/cm.sup.2, and then water is distilled out 
until the pressure can not be maintained at this value any more. The 
pressure is reduced to normal pressure in about 1 hour, and then the 
reaction is continued for 1.5 hours under normal pressure. The highest 
polymerization temperature is 255.degree. C. Thus, a polyamide is obtained 
as a milky white solid substantially insoluble to water. Softening point, 
about 110.degree. C. Specific viscosity, 1.59. 
The above obtained polymer (100 parts), methacrylic acid (10 parts), 
acrylamide (20 parts), methylenebisacrylamide (10 parts), benzophenone (2 
parts) and hydroquinone (0.2 part) are dissolved in methanol (300 parts) 
under heating. The resultant solution is poured on the surface of a glass 
plate and allowed to stand under reduced pressure as so to evaporate the 
methanol completely, whereby a transparent photosensitive resin 
composition film of 0.8 mm in thickness is obtained. The resin composition 
is readily soluble in water at room temperature. 
The film is stuck on a polyethylene terephthalate film of 0.2 mm in 
thickness, and a negative film is placed on the photosensitive layer. 
Then, exposure is effected by irradiation with a fluorescent lamp for 
reproduction BA-37 (manufactured by Matsushita Electric Industrial Co., 
Ltd.) for 4 minutes. The irradiated product is developed in a neutral 
water stream at 20.degree. C. for 3 minutes under a pressure of 0.5 
kg/cm.sup.2, whereby a relief printing plate in which the original image 
is reproduced accurately and which shows an excellent printability is 
obtained. 
EXAMPLE 2 
In a reactor, the nylon salt of 
6-methyl-6-(N,N'-diethylaminomethyl)-4,8-dioxaundecanediamine with adipic 
acid (100 parts) and water (100 parts) are charged, and after sufficiently 
replacing the atmosphere by nitrogen, the temperature is elevated. When 
the inner pressure reaches 5 kg/cm.sup.2, the distilling out of water is 
effected so as to maintain the pressure at this value. When 80% of the 
added water is distilled out, the pressure begins to be reduced gradually 
and is made normal in about 30 minutes. The reaction is continued at 
260.degree. C. for 2 hours under normal pressure in a nitrogen stream to 
obtain a polyamide as a pale yellow solid. Softening point, 125.degree. to 
127.degree. C. Specific viscosity, 1.58. 
The thus obtained polyamide (100 parts), methacrylic acid (12 parts), 
ethylene glycol dimethacrylate (8 parts), methyl methacrylate (15 parts), 
benzophenone (2 parts) and hydroquinone (0.1 part) are dissolved in 
methanol (200 parts) under heating, and the resulting solution is 
concentrated to remove the methanol, whereby a solid transparent 
photosensitive resin composition is obtained. This composition is readily 
soluble in cold water. 
The thus obtained photosensitive resin composition is subjected to 
preparation of a photosensitive material, which is then exposed, developed 
and dried as in Example 3 whereby a relief printing plate having a good 
printability in which the original image is accurately reproduced is 
obtained. 
EXAMPLE 3 
A homopolyamide (100 parts) obtained by polycondensation of the nylon salt 
of N,N'-bis(3-aminopropyl)-piperazine with sebacic acid is dissolved in 
methanol (300 parts). To the resultant solution, 20% hydrochloric acid (50 
parts) and glycidyl methacrylate (58.5 parts) are added, and the mixture 
is stirred for 24 hours under reflux in a water bath of 75.degree. C. The 
reaction mixture is dropwise added to a largely excess amount of ethyl 
acetate under stirring to precipitate a glycidyl methacrylate-modified 
polyamide, which is collected by filtration and dried. The polyamide is 
again dissolved in an about three times amount of methanol and 
reprecipitated with ethyl acetate to obtain the modified polyamide (123 
parts) as a white solid soluble in water and methanol. 
To a solution of the above obtained modified polyamide (10 parts) in 
methanol (40 parts), benzoin methyl ether (0.1 part) and hydroquinone 
monomethyl ether (0.02 part) are added to make a uniform solution, from 
which the methanol is removed by evaporation in a dark room. The residue 
is dried at 40.degree. C. for 16 hours under reduced pressure whereby a 
uniform transparent sheet of 0.54 mm in thickness is obtained. 
A part of the sheet is subjected to irradiation by the aid of a low 
pressure mercury lamp (500 W) for 5 minutes from a distance of 10 cm and 
then extracted with methanol by a Soxhlet's extractor for 24 hours. The 
degree of gelation is 93.4%. The non-irradiated sheet is soluble in water 
and methanol. 
REFERENCE EXAMPLE 1 
The procedure as in Example 3 is repeated except that water (50 parts) is 
employed in place of 20% hydrochloric acid (50 parts) to obtain a 
polyamide being soluble in methanol but not soluble in water. 
Using the polyamide (10 parts) in place of the modified polyamide (10 
parts), the same procedure as in Example 3 is repeated to make a uniform 
transparent sheet. The degree of gelation determined by methanol 
extraction after exposure is 0%. The non-irradiated sheet is also soluble 
in methanol. 
EXAMPLE 4 
A copolymerized polyamide (10 parts) obtained by polycondensation of 
.epsilon.-caprolactam (50 parts) and the nylon salt of 
N-(2-aminoethyl)piperazine with adipic acid (50 parts) is dissolved in 
ethanol (40 parts), and 20% hydrochloric acid (3.05 parts) and glycidyl 
acrylate (3.22 parts) are added thereto. The mixture is stirred for 24 
hours under reflux in a water bath of 85.degree. C. The reaction mixture 
is treated with ethyl acetate so as to precipitate a glycidyl 
acrylate-modified polyamide as a white solid as in Example 3. 
The thus obtained modified polyamide (5 parts), benzophenone (0.05 part) 
and hydroquinone monomethyl ether (0.01 part) are dissolved uniformly in 
methanol (20 parts), and the solution is evaporated in a dark room to 
remove the methanol. The residue is dried at 40.degree. C. for 16 hours 
under reduced pressure whereby a uniform transparent sheet of 0.47 mm in 
thickness is obtained. 
A part of the sheet is subjected to irradiation for 4 minutes by the aid of 
a low pressure mercury lamp (500 W) from a distance of 10 cm, and then 
extracted with methanol. The degree of gelation is 87.6%. The 
nonirradiated sheet is soluble in water and methanol. 
EXAMPLE 5 
A copolymerized polyamide (10 parts) obtained by polycondensation of 
.epsilon.-caprolactam (60 parts) and the nylon salt of 
N,N'-bis(3-aminopropyl)piperazine with adipic acid (40 parts) is dissolved 
in ethanol (30 parts) and water (10 parts), and acrylic acid (0.94 part) 
and glycidyl methacrylate (2.70 parts) are added thereto. The mixture is 
stirred for 24 hours under reflux in a water bath of 85.degree. C. To the 
reaction mixture, benzoin methyl ether (0.2 part) and hydroquinone 
monomethyl ether (0.05 part) are added to make a uniform solution, from 
which the ethanol is removed by evaporation in a dark room. The residue is 
dried at 40.degree. C. for 24 hours under reduced pressure to obtain a 
sheet. The sheet is cut into pieces and pressed at 130.degree. C. to give 
a uniform transparent sheet of 0.65 mm in thickness, which is stuck to an 
iron plate to make a uniform photosensitive material. 
The photosensitive material is closely contacted with a negative film in 
vacuo and subjected to irradiation for 3 minutes by the aid of a chemical 
lamp (400 W) from a distance of about 5 cm. The irradiated material is 
sprayed with tap water at 30.degree. C. through a nozzle under a pressure 
of 4 kg/cm.sup.2 so as to remove the non-irradiated part, whereby a 
distinct relief printing plate in which the original image is accurately 
reproduced is obtained. The printability of the relief printing plate is 
excellent.