GB1580959A - Substituted acrylamide and polymers - Google Patents

Description

(54) SUBSTITUTED ACRYLAMIDE AND RELATED POLYMERS (71) We, KONISHIROKU PHOTO INDUSTRY CO LTD, a corporation organized under the laws of Japan, of 1-10, 3-chome, Nihonbashi-Muro-machi, Cho-ku, Tokyo, Japan, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to a photosensitive polymer which becomes insoluble by light exposure and particularly to a highly photosensitive polymer having, as photosensitive groups, both an cr,p-unsaturated ketone group having a cyano group in the a-position, and an azide group. Azide compounds release nitrogen gas on photolysis to form nitrene which is a free radical. It is known that when a photosensitive polymer having a large number of azide groups is exposed to an actinic light, the resulting nitrene brings about a dehydrogenation reaction, an addition reaction to double bonds and/or a coupling reaction with itself, and, in consequence, the exposed polymer undergoes a photo-crosslinking reaction to become insoluble in aqueous alkali solutions or organic solvents.

It is also known that an a,p-unsaturated ketone group in a polymer causes it to dimerise upon exposure to actinic light forming a 4-membered ring, and thus an cu,p-unsaturated ketone containing polymer is rendered insoluble. By making use of such properties, it is possible to obtain a negative relief image corresponding to the image of original by imagewise exposing a photosensitive material having coated, on a suitable support, a photosensitive composition containing such an azide compound or an a,p-unsaturated ketone compound and dissolving off the unexposed portion by development with an aqueous alkali solution or an organic solvent. The resulting relief image can be used as an offset printing plate, a letterpress printing plate, a wash off film or a name plate, for example. Further, the relief image can also be used for the preparation of, for example, a photogravure plate or a printed circuit substrate by using and etching the substrate and leaving the relief image as a resist.

Various polymers having azide or a,ss-unsaturated ketone groups as photosensitive groups are known, for instance polyvinyl azidobenzoate and polyvinyl cinnamate. However, these materials are not particularly photosensitive, so that sensitizers must be used in combination with them if they are to be of practical use.

Photosensitive compositions having enhanced sensitivity include those having azidocinnamic groups as disclosed, for example, in Journal of Polymer Science, part B, Vol. 9, pp.

81-83 (1971) and part A-l, Vol. 10, pp. 2379-2387 (1972) and those having cinnamylidene acetic acid groups as disclosed, for example, in U.S. Patent 3,257,664. These materials, however, possess that they have poor storage stability. Photosensitive polymers having a-cyanocinnamic acid groups as photosensitive groups, disclosed in U.S. Patent 2,824,084, on the other hand, have excellent storage stability but are less sensitive than those polymers having azido-(x-cyanocinnamic acid groups.

Polymers having, as photosensitive groups, both an a,p-unsaturated ketone group (which has a cyano group at the a-position) and an azide group might be expected to possess excellent storage stability and sensitivity; polyvinyl-p-azido -a-cyanocinnamate is a known polymer of this type (see Journal of The National Chemical Laboratory for Industry, Vol. 68, pp. 90-94, 1973).

This photosensitive polymer, however, is an esterified compound obtained by reacting an alcoholic hydroxyl group with p-azido-a- cyanocinnamic acid chloride; accordingly it has to be developed with an organic solvent and in order to carry out development with an aqueous alkaline solution it is necessary to incorporate an alkali-soluble component. When such a polymer is copolymerized with an acrylic acid or the like, as the alkali-soluble component, difficulties arise during development with an aqueous alkaline solution, as excessive swelling of a relief occurs and there is a reduction in adhesion.

An object of the present invention is, therefore, to provide a photosensitive polymer substantially free from such drawbacks, having good photosensitivity, and photosensitive compositions containing it having excellent physical, chemical and imagewise properties.

We have found, according to the present invention, that this can be accomplished with a photosensitive polymer having recurring structural units of the following general formula (I) (hereinafter called "the present polymer"):

wherein R1 represents hydrogen or an alkyl or carboxyl group; R2 represents hydrogen, halogen or an alkyl group; R3 represents hydrogen, an alkyl group, an aryl group or an aralkyl group; Y and Z individually represent an arylene group; X represents a divalent organic group connecting the adjacent nitrogen atom to an aromatic ring carbon atom of Y; and n represents 0 or 1.

An aryl group and an aralkyl group for R3 are preferably phenyl and benzyl respectively.

An arylene group for Y and Z is preferably phenylene or naphthylene, which phenylene for Y may be substituted, preferably with cyano, methyl and/or methoxy while the naphthylene for Y may be substituted, preferably with a sulfonic acid. In fact the nature of the substituent is relatively unimportant since it hardly affects the characteristic polymer. Typical substituents include an alkyl group, an alkoxy group, halogen, acyl, hydroxyl, carboxyl, a sulfonic acid, cyano and nitro. The phenylene or naphthylene for Z may be substituted with, for example, nitro and/or chlorine. An alkyl group for R2 and R3 is preferably methyl or ethyl. Halogen for R2 is preferably chlorine or bromine. A divalent group for X is preferably an alkylene group, especially methylene or ethylene.

The present polymer has good sensitivity, excellent storage stability and excellent film forming properties; it also has good physical properties, especially mechanical strength.

Further, the present polymer has excellent adhesion to various kinds of supports. A photosensitive composition containing the present photosensitive polymer may be developed with either an organic solvent or a dilute aqueous alkaline solution, depending on the molar ratio of the p-azido-a-cyanocinnamoyl group in the polymer and, moreover, the swelling thereof during development is extremely small. Accordingly such photosensitive compositions enable one to obtain resist which is very strong and the adhesion between the resist and support is also strong. Particularly when the composition is used as a resist for letterpress printing, a film-hardening step after development treatment and a burning treatment step may be omitted.

When the present photosensitive composition is used for offset printing, because of the improved physical strength of the polymer, the printing durability of the composition is markedly better than that of the prior art compositions. Furthermore, because of excellent resistance to an etching solution, the non-etched portion of the present composition is hardly damaged during the preparation of a letterpress printing plate, an intaglio printing plate, a name plate or a printed circuit board, for example.

The polymer of the present invention may be a homopolymer comprising only structural units of formula (I) or a copolymer comprising repeating units of formula (I) and other structural units derived from a vinyl type (unsaturated double bond) monomer. Other copolymers include those wherein in some of the structural units of fomula (I) there is a hydroxyl group in place of the -OCO-(CN) = CH-Z-N3. Suitable vinyl monomers include ethylenic unsaturated olefins such as ethylene, propylene, butylene, isobutylene and butadiene; styrenes such as styrene, a-methylstyrene and p-chlorostyrene; an acrylic acid; a methacrylic acid; an itaconic acid; a maleic acid; maleic anhydride; esters such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, n-octyl acrylate, 2-chloro-ethyl acrylate, phenyl acrylate, methyl a-chloroacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate and ethyl methacrylate; acrylonitrile; methacrylonitrile; acrylamide; methacrylamide; a-ethylacrylamide; acrylanilide; p-chloroallylanilide; m-nitroacrylanilide; m-methoxyacrylanilide; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; vinyl esters such as vinyl acetate, vinyl propionate, vinyl benzoate and vinyl lactate; vinyl chloride; vinylidene chloride, vinylidene cyanide; ethylene derivatives such as 1-methyl-1' -methoxyethylene, 1,1'-dimethoxyethylene, 1,2dimethoxyethylene, 1, 1'-dimethoxycarbonylethylene and l-methyl-l'- nitroethylene and N-vinyl compounds such as N-vinylindole, N-vinyl pyrrolidene and N-vinylpyrrolidone.

Typical examples of the polymer of the present invention are examplified below. In the following exemplified compounds, "Mn" represents the average molecular weight, and l:m:n or m:n represents the mole ratio of their respective structural units.

The present polymer may be synthesised in a variety of ways. For instance, an a,pa unsaturated acid chloride or a,p-unsaturated acid anhydride is allowed to react, if necessary in the presence of a basic catalyst, with a primary or secondary amine having a phenolic hydroxyl group to prepare a monomer having the same structural unit of the general formula (I) but with a hydroxyl group in place of the -OCO-C(CN) = CH-Z-N3 3 group. Thereafter, the monomer thus prepared is either homopolymerized or copolymerized with at least one vinyl monomer to obtain a polymer having a phenolic hydroxyl group, in a conventional manner.

The polymer thus obtained is allowed to react, in an organic solvent miscible with water in the presence of an alkali, with an acid chloride of the general formula (II):

(wherein Z is as defined before), thereby to esterify the phenolic hydroxyl group. Alternatively, the polymer having a phenolic hydroxyl group is allowed to react, in the presence of a tertiary amine, such as pyridine or triethylamine, as a basic catalyst, with an acid chloride of the aforementioned general formula (II). In this process, the molecular weight of the polymer of the present invention may be controlled over a wide range relatively easily by appropriate selection of, for example, the temperature during the polymerization reaction, the nature of the reaction medium used and the amount of the polymerization initiator. Further, the mole content of the structural unit of the general formula (I) the present invention may optionally be controlled, for example by varying an amount of the acid chloride of the general formula (II), or the nature and amount of the reaction medium used.

Thus, the present polymer can be obtained with the desired molecular weight and molar content of the structural unit of the general formula (I). The molecular weight of the polymer is suitably from 2,000 to 1,000,000 and the mole content of the structural unit of the general formula (I) is generally not less than 10 mole %.

By incorporating into the present polymer an appropriate amount of an alkali-soluble component having an alkali-soluble group such as a carboxylic acid, a sulfonic acid or a phenolic hydroxyl group, it becomes possible for a photosensitive composition in which the present polymer is present to be developed with an aqueous alkaline solution.

The following Synthesis Examples further illustrate the preparation of the polymers of the present invention.

Synthesis Example 1 Preparation of compound (1) A mixture comprising 400 g of p-hydroxyaniline, 4 g of hydroquinone monomethyl ether, 4 g of acetone and 360 g of pyridine was externally cooled, and thereto was dropwise added with stirring 420 g of methacrylic acid chloride when the internal temperature of the mixture was down to -10 C. The rate of addition of the methacrylic acid chloride was controlled so that the reaction temperature could be maintained at a temperature below 0 C. and, after completion of the addition, the resulting mixture was stirred at 0 to 3"C. for about 2 hours, followed by stirring at 250C. for 2 hours. Thereafter, the reaction liquid was concentrated to about 1/3 of the original volume, the concentrated reaction liquid was poured into 10 liters of dilute hydrochloric acid (pH about 1.0), the precipitate was filtered by suction to obtain a white solid. The white solid was dissolved by heating in 2 litres of methanol, the resulting solution was further charged with 2 liters of a 5% sodium carbonate solution, and the resulting mixed solution was stirred at 40"C. for 30 minutes to obtain a dark red solution.

Subsequently, this dark red solution was poured into 8 liters of a 5% aqueous hydrochloric acid solution to form a large amount of precipitate, the precipitate was filtered by suction and dried to obtain a pale pink solid. The pale pink solid was recrystallized from a mixed solvent of ethanol and water to obtain 450 g of white crystals of p-hydroxymethacrylanilide, m.p.

155"-156"C.

A solution of 124 g of p-hydroxymethacrylanilide obtained in the above manner, 1.149 g of aa'-azobis-isobutyronitrile and 1.416 g of dodecylmercaptan in 350 ml of a 1:1 mixture of acetone and methanol was heated at 65"C. for 30 hours in a sealed tube filled with nitrogen gas to obtain a polymer solution. This polymer solution was poured into water, the white precipitate was filtered and then dried to obtain 101 g of a white polymer (A).

The molecular weight of this polymer (A) as measured according to the osmotic pressure method was about 23000.

In a mixture comprising 400 ml of dry pyridine and 60 ml of y-butyrolactone was completely dissolved 30 g of this white polymer (A), the solution was maintained at 500C.

and 9.85 g of p-azido-cx-cyanocinnamic acid chloride was added in small portions. After completion of the addition of said acid chloride, the mixture was allowed to undergo reaction at 50 C. for 5 hours whereupon the reaction mixture became a transparent pale yellow solution. This solution was allowed to stand overnight at room temperature and then poured into a mixture of 3 liters of iced water and 80 ml of concentrated hydrochloric acid to deposit a precipitate. The precipitate was filtered by suction, water-washed and then dried to obtain 35 g of compound (1).

Synthesis Example 2 Preparation of compound (2) A mixture comprising 104 g of m-hydroxyaniline, 0.5 g of hydroquinone monomethyl ether, 170 g of methacrylic anhydride and 200 ml of water was allowed to undergo reaction at 70"C. for 2 hours and then cooled. The precipitate formed by adding 500 ml of a 5% hydrochloric acid to the reaction liquid was filtered by suction to obtain a white solid. After dissolving, by heating, the white solid in 500 ml of methanol, the resulting solution was stirred together with 500 ml of a 5% aqueous sodium carbonate solution at 400C. for 30 minutes.

Thereafter, the resulting mixture was poured into 2 liters of a 5 % hydrochloric acid to form a large amount of precipitate. The precipitate thus formed was filtered by suction and then recrystallized from ethanol to obtain 130 g of white crystals of m-hydroxymethacrylanilide, m.p. 171"- 173"C.

solution of 124 g of m-hydroxymethacrylanilide obtained above and 1.15 g of a,a'azobisisobutyronitrile in 350 ml of a 1:1 mixture of acetone and methanol was heated at 65"C. for 30 hours in a nitrogen gas-filled and sealed tube to obtain a polymer solution. After diluting this polymer solution with 200 ml of a 1:1 mixture of methanol and acetone, the polymer solution was poured into water, the white precipitate was filtered and then dried to obtain 121 g of a polymer (B). The molecular weight of this polymer (B) as measured according to the osmotic pressure method was about 45000.

Into a solution of 30 g of this white polymer (B) and 15.8 g of p-azido-a-cyanocinnamic acid chloride in a mixture comprising 600 ml of tetrahydrofuran and 20 ml of water, was dropwise added with stirring at 400C. 120 ml of 1N sodium carbonate solution. After completion of the addition, the reaction liquid was poured, after stirring for 30 minutes, into 3 liters of dilute hydrochloric acid to form a precipitate. The precipitate was filtered by suction, water-washed and then dried to obtain 41 g of compound (2).

Synthesis Example 3 Preparation of compound (4) A solution of 141.6 g (0.8 mole) of p-hydroxy-methacrylanilide obtained in Synthesis Example 1, 17.2 g (0.2 mole) of methacrylic acid and 1.64 g of a,a'-azobisisobutyronitrile in 350 ml of a 1:1 mixture of acetone and methanol was heated at 650C. for 30 hours in a nitrogen gas-filled and sealed tube to obtain a copolymer solution. After diluting 100 ml of methanol, this copolymer solution was poured into water to form a precipitate. The precipitate was filtered and then dried to obtain 130 g of a copolymer (C). The molecular weight of this copolymer (C) as measured according to the osmotic pressure method was about 38000.

Into a solution of 10 g of this copolymer (C) completely dissolved in 130 ml of dry pyridine and maintained at 500C. was added with stirring 7.9 g of m-azido-a-cyanocinnamic acid chloride in small portions. After completion of the addition, the mixture was allowed to undergo reaction at 550C. for 5 hours. After allowing to stand overnight at a room temperature, the reaction mixture was poured into 3 liters of cooled dilute hydrochloric acid to form a precipitate. The precipitate was filtered by suction, water-washed and then dried to obtain 15.8 g of compound (4).

Synthesis Example 4 Preparation of compound (13) Into a mixture comprising 227 g of 5-amino-a-naphthol, 1 g of hydroquinone monomethyl ether and 2 liters of pyridine was dropwise added with stirring 110 g of methacrylic acid chloride cooled to - 1 00C. After completion of the addition, the mixture was stirred at 00-30C.

for 2 hours, followed by stirring at 25"C. for 2 hours. Thereafter, the reaction liquid was poured into 20 liters of water to form a precipitate which was then filtered, water-washed and then dried to obtain a solid. The solid was added to 2 liters of a 1:1 mixture of methanol and a 5 % sodium carbonate solution, and after stirring at 40"C. the mixture was poured into 4 liters of a 5 % hydrochloric acid to form a large amount of precipitate. The precipitate was filtered by suction and then recrystallized from ethanol to obtain 210 g of N-(5-hydroxy-a-naphthyl) methacrylamide, m.p. 223 -224 C.

A solution of 182 g (0.8 mole) of N-(5-hydroxy-a-naphthyl) methacrylamide, 14.4 g (0.2 mole) of acrylic acid, 1.64 g of a,a'-azobisisobutyronitrile and 2.02 g of dodecylmercaptol in 600 ml of a 1:1 mixture of acetone and methanol was heated at 550C. for 40 hours in a nitrogen gas-filled tube to obtain a copolymer solution.

After diluting with 200 ml of methanol, this copolymer solution was poured into water to form a precipitate which was then filtered and dried to obtain 192 g of a copolymer (D). The molecular weight of this copolymer (D) as measured according to the osmotic pressure method was about 19000.

Into a solution of 30 g of this copolymer (D) in a mixture of 400 ml of dry pyridine and 100 ml of y-butyrolactone and maintained at 500C. was added 11.8 g of pazido-a-cyanocinnamic acid chloride in small portions. After completion of the addition, the mixture was allowed to undergo reaction at 500C. for 5 hours and the reaction mixture was then poured into a mixture of 4 liters of iced water and 80 ml of a concentrated hydrochloric acid to form a precipitate. The precipitate was filtered by suction, water-washed and then dried to obtain 38 g of compound (13).

The polymer of the present invention have excellent photosensitivity and hence it is necessary to store them in a dark place. When stored in a dark place the present high molecular compounds can remain for a long time without decomposition; at the same time, they are less hygroscopic and less liable to deteriorate.

The present invention also provides a photosensitive composition which contains as a photosensitive component at least one polymer of the present invention and an organic solvent. The polymers of the present invention are generally resins having a high molecular weight and have excellent film-forming properties, free from crystal deposition, and also possess excellent storage stability as well as adhesivity. Thus, a favorable photosensitive composition can be obtained simply by dissolving the present polymer in an organic solvent.

In order to improve coating properties and developability, other resins may be incorporated.

For instance, where the photosensitive composition is intended to be subjected to alkali development alkali-soluble resins may be mixed with the present polymer. Such alkalisoluble resins include, for example, natural resins such as shellac and rosin; novolac resins such as a phenol formalin novolac resin and an m-cresol formalin novolac resin; homopolymers or copolymers of unsaturated carboxylic acids, such as a polyacrylic acid, a polymethacrylic acid, a methacrylic acid-styrene copolymer, a methacrylic acid-methyl acrylate copolymer, a maleic anhydride-vinyl compound copolymer, an acrylic acid-vinyl compound copolymer and a methacrylic acid-vinyl compound copolymer; resins obtained by partially acetalating partial or complete saponification products of polyvinyl acetate with aldehydes such as acetaldehyde, benzaldehyde, hydroxybenzaldehyde and carboxybenzaldehyde; and homopolymers of monomers corresponding to those as having introduced into the structural unit of general formula (I) a hydroxyl group in place of the -OCO-C(CN) = CH-Z-N3 group or copolymers thereof with other vinyl monomers. Further, if necessary, resins soluble in organic solvents may be included, for example cellulose alkyl ethers such as cellulose methyl ether and cellulose ethyl ether. Because of this excellent compatibility with these resins, the present polymers may advantageously be used in combination with these resins. Particularly, cellulose alkyl ethers are effective in improving coating properties; the addition of a small amount to the composition gives good results even when the composition is subjected to an alkali development. The photosensitive compositions according to the present invention may also contain known azide compounds such as 1-azidopyrene and 4,4'-diazidochalcone as photosensitive components in addition to the present polymer, and further may contain various other additives. For instance, the composition may contain dyes such as acridine, cyanine, merocyanine, styryl and triphenylmethane dyes or pigments, which are used as coloring materials to make images visible. Similarly, photochromogenic substances or photoversicolor substances may also be incorporated for the purpose of visualizing images by exposure to light. Such photochromogenic substances or photoversicolor substances include, for example, combinations of aromatic azides, carbonyl azide or sulfonyl azides with leuco dyes. The amount of such dye or visualising substance to be added varies depending on the degree of visualization of the image required. Generally, however, the amount is 0.01 to 0.1 times by weight, the weight of the present polymer. Similar comments apply to the dyes.

Further, the aforementioned alkali-soluble resins, resins soluble in organic solvents or other azide compounds are suitably incorporated into the composition in an amount from 0.1 to 10 times the weight of the present polymer present in the composition.

The photosensitive composition according to the present invention may contain plasticizers which are compatible with the present polymer. For instance, plasticizers such as phthalate esters, phosphate esters, esters of aliphatic carboxylic acids, glycol derivatives and sulfonamides are quite useful. When such plasticizers are incorporated into the present photosensitive composition, not only good pliability is imparted to the photosensitive layer of the resulting photosensitive compostion thereby improving the extensibility of the layer but also the coating properties are improved when the photosensitive layer is formed on a support thus improving markedly the film-forming properties. Further, adhesion of the photosensitive layer to a support, for example, an aluminum plate, is markedly improved. Moreover, when the resulting photosensitive composition is coated on a support and then used as a printing plate, the line drawing of the photosensitive layer appearing upon development is prevented from swelling and thus the strength of the relief of the line drawing is markedly enhanced. The use of plasticizers also enables one to increase development flexibility , such that fluctuations in the properties of the finished relief images can be eliminated, uneven development and undesirable adherence of ink to the non-line drawing portion can be prevented and, further, the line drawing portion can have improved ink-receptivity.

The amount of the plasticizer used in the present photosensitive composition is generally 0.05 to 0.5, preferably 0.15 to 0.25, times the weight of the present polymer.

Furthermore, the photosensitive composition according to the present invention can also contain sensitizers for the purpose of improving further the sensitivity or photosensitive wavelength region of the composition. Suitable sensitizers are, for example, Michler's ketone, 9-fluorenone, 1-nitropyrene, 1,8-dinitropyrene, 2-chloro-1,2- benzanthraquinone, pyrene- 1,6- quinone, anthanthrone, 2-chloro-1,8- phthaloyl- naphthalene and cyanoacridine. The amount of the sensitizer present in the photosensitive composition is preferably 0.1 to 2.0 parts by weight per 100 parts by weight of the aromatic azide polymer.

The photosensitive composition according to the present invention may be coated and dried on a suitable support such as an aluminum plate, zinc plate, copper plate, plastic film, paper or laminated plate, e.g. a bimetal or trimetal. A coating solution desirably contains the total solids of said composition in a concentration from 0.1 to 50% by weight based on the organic solvent in the coating liquid. Suitable organic solvent includes the monomethyl and monoethyl ether of ethylene glycol, referred to by the Registered Trade Marks methyl and ethyl "Cellosolve", respectively, dioxane, acetone, cyclohexanone, y-butyrolactone tetrachloroethane, tetrahydrofuran, dimethylsulfoxide, dimethylformamide and methyl Cellosolve acetate. The photosensitive composition according to the present invention is quite stable and can be stored for a long time in a dark place, and a photosensitive material obtained by coating said composition on a support, followed by drying, may also be stored satisfactorily for several months in a dark place.

Any conventional procedure may be applied to the photosensitive material. For instance, an original having a line or halftone image can be brought into close contact with a photosensitive layer of a photosensitive material and the material exposed to light. The exposed material is then developed with an aqueous alkaline solution or organic solvent to obtain a negative relief image corresponding to the original. Preferable light sources for the exposure are an carbon arc lamp, a mercury lamp, a xenon lamp, a chemical lamp and a photographic flash lamp. The aqueous alkaline solution used for the development is suitably an aqueous solution of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium metasilicate, sodium secondary phosphate or sodium tertiary phosphate. For the purpose of preventing a developer solution from becoming exhausted, there may be used an alkaline buffer or, if necessary, an aliphatic amine such as mono-, di- or trihydroxyethylamine or mono-, di- or triethylamine. The concentration of the aqueous alkaline solution may vary depending on the nature of the photosensitive composition and alkali employed; however, a concentration from 0.1 to 10% by weight is generally suitable. In order to accelerate development and to prevent an uneven treatment, a small amount of a surface active agent or water-miscible o negative original of a line and halftone photographic image was placed in contact with the photosensitive surface of the photosensitive plate and exposed for 3 minutes to light from a 3 KW mercury lamp at the distance of 1 m. The exposed plate was immersed for 1 minute in a 3% aqueous sodium metasilicate solution and, thereafter, the exposed surface of the plate was rubbed softly with absorbent cotton, whereupon the unexposed portion was removed and a positive relief image having excellent oil-suspectivity was obtained. After imparting water-retainability to the relief image, the plate was placed in an offset press, and many prints, each having an image of good quality, were obtained.

Example 2 A solution of 10 g of compound (2) obtained in Synthesis Example 2, 0.7 g of 5-nitroacenaphthene, 400 g of cellulose ethyl ether and 100 mg of a triphenylmethane type dye (Victoria Pure Blue BOH, produced and sold by Hodogaya Kagaku K.K.) in 100 ml of a 2:8 mixture of dimethylformamide and methyl Cellosolve was coated by means of a coating machine on the polished surface of a printing zinc plate and then dried. A transparent film original was placed in contact with the photosensitive surface of the thus obtained photosensitive plate, and the resulting unit was set in a vacuum printing machine and exposed for about 1 minute at the distance of about 40 cm to light from a carbon arc lamp. The exposed plate was then developed with a 1 % aqueous sodium hydroxide solution and the unexposed portion was removed to obtain a blue negative relief image having high acid resistance corresponding to the original, followed by etching with an ordinary Dow etching solution and waterwashing. The resultant plate was placed in a letterpress printing machine to obtain many prints having a sharp bordered print image.

Example 3 A solution of 5 g of compound (2) obtained in Synthesis Example 2, 0.3 g of Michler's ketone, 150 mg of cellulose ethyl ether and 1 g of N-butylpyrrolidone in 100 ml of methyl Cellosolve was coated on a grained aluminum plate by a coating machine and then dried. A negative original of a line drawing and halftone photograph was placed in contact with the photosenstive surface of the thus obtained photosensitive plate, and the resulting unit was exposed for 5 minutes to light from a chemical lamp. The exposed plate was developed with a 6% aqueous sodium metasilicate solution, whereby the unexposed portion was removed to obtain a positive relief image. Subsequently, the surface of the resultant plate was treated with a 1 % aqueous phosphate solution and then placed in an offset press to obtain many prints having a corresponding image of good quality.

Example 4 A solution of 10 g of compound (4) prepared in Synthesis Example 3, 3 g of formalin novolac resin and 60 mg of a triphenylmethane type dye (Victoria Blue Base F.4.R, produced and sold by BASF Co.) was coated on an ordinary print substrate (a plate prepared by laminating a copper foil on a support such as "Bakelite" (Registered Trade Mark) plate, phenol paper or epoxy paper) and then dried. The photosensitive plate obtained was brought into contact with its photosensitive surface) with a transparent negative film original, set in a vacuum printing machine, and then exposed for 2 minutes at the distance of about 90 cm to light from a 3KW mercury lamp, developed for 1 minute with an aqueous solution containing 5% by weight of sodium tertiary phosphate and 3% by weight of isopropyl alcohol and then dried to obtain a positive relief image. Subsequently, the thus treated plate was etched by immersing it in a 40% by weight aqueous solution of ferric chloride and, thereafter, the relief image was dissolved and removed with y-butyrolactone to obtain a favorable printed circuit board.

Example 5 A solution of 10 g of compound (13) prepared in Synthesis Example 4, 0.5 g of 2-nitrofluorene, 2 g of naphthoquinone-1, 2-diazido-2, 5-sulfonazide, 1 g of tricresyl phosphate and 200 mg of 2-(p-dimethylaminostyryl) -benzthiazole in a 1:3 mixture of y-butyrolactone and cyclohexanone was coated on a rough surfaced aluminum plate and then dried. The photosensitive plate obtained was brought into contact (with its photosensitive surface) with a negative transparent film original, set in a vacuum printing machine and then exposed for 2 minutes to light from a 500 W tungsten lamp to obtain a dark red, sharp image.

The image was then developed with a 10:4 mixture of methyl Cellosolve and wy-butyrolactone to obtain a positive relief image having excellent oil-susceptibility and mechanical strength.

The plate was placed in an offset press to obtain many prints having a corresponding image of good quality.

Example 6 A solution of 7 g of compound (13) prepared in Synthesis Example 4, 500 mg of Victoria Pure Blue BOH and 50 mg of cellulose ethyl ether in 100 ml of a 1:1 mixture of dimethylformamide and cyclohexanone was coated on a polyester base and then dried. The photosensitive film obtained was brought into contact (with its photosensitive surface) with a negative original and then exposed for 4 minutes at the distance of 1 meter to light from a 3KW mercury lamp, and developed with a 8% aqueous sodium tertiary phosphate solution to obtain a blue, sharp positive image. The plate having the positive image was found to be useful wash off film for various techniques including proof, a title plate for color TV, a title for a motion picture, phototypesetting, instant lettering, typetone and screentone.

WHAT WE CLAIM IS: 1. A polymer having recurring structural units of the general formula:

wherein R1 represents a hydrogen atom, or an alkyl or carboxyl group; R2 represents a hydrogen or halogen atom or an alkyl group; R3 represents a hydrogen atom or an alkyl, aryl or aralkyl group; Y represents an arylene group; X represents a divalent organic group connecting the adjacent nitrogen atom and an aromatic ring carbon atom of Y; A represents a group of formula -OCO-C(CN) = CH-Z-N3, wherein Z represents an arylene group; and n represents 0 or 1.

?,. A polymer according to claim 1 wherein X is an alkylene group.

3. A polymer according to claim 2 wherein X is methylene or ethylene.

4. A polymer according to any one of claims 1 to 3 wherein X is

5. A polymer according to any one of claims 1 to 4, wherein A represents a group of formula -OCO-C(CN) = CH-Z-N3 in at least 10 mole % of the total recurring structural units present in the polymers.

6. A polymer according to any one of the preceding claims which also contains recurring structural units of formula (I) in which A represents a hydroxyl group.

7. A polymer according to any one of the preceding claims which also contains structural units derived from addition polymerisation of an ethylenically unsaturated monomer.

8. A polymer according to any one of the preceding claims wherein Y and Z represent an unsubstituted or substituted phenylene group or naphthylene group.

9. A polymer according to claim 8, wherein Y and Z represent a phenylene or naphthylene group.

10. A polymer according to any one of the preceding claims wherein R1 is methyl.

11. A polymer according to any one of the preceding claims wherein R3 represents a hydrogen atom or an alkyl, phenyl or aralkyl group and Y and Z independently represent an unsubstituted or substituted phenylene or naphthylene group.

12. A polymer according to any one of the preceding claims wherein R3 represents phenyl or benzyl.

13. A polymer according to any one of claims 1 to 11 wherein R2 is chlorine or bromine and R2 and R3 are methyl or ethyl.

14. A polymer according to any one of claims 1 to 8 and 10 to 13 wherein Y is cyano, methyl and/or methoxy substituted phenylene and Z is phenylene or naphthylene substituted with nitro and/or chlorine.

15. A polymer according to any one of claims 1 to 8 and 10 to 13 wherein Y is naphthylene substituted with a sulfonic acid.

16. A polymer specifically hereinbefore identified as (1) to (13).

17. A photosensitive composition which comprises a polymer as claimed in any one of the preceding claims and an organic solvent.

18. A composition according to claim 17 which comprises an alkali-soluble resin.

19. A composition according to claim 17 or 18 which comprises cellulose methyl ether and/or cellulose ethyl ether.

20. A composition according to any one of claims 17 to 19 wherein the polymer is one claimed in claim 11.

21. A composition according to any one of claims 17 to 20 which comprises 1-azidopyrene.

22. A composition according to claim 17 substantially as described in any one of Examples 1 to 6.

23. A process of producing an image in a polymeric material, which process comprises imagewise exposing a layer of a polymer as claimed in any one of claims 1 to 16 carried on a support, to a photosensitising radiation and developing the resultant latent image.

24. A process according to claim 23 wherein the polymer is one claimed in claim 11.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (25)

**WARNING** start of CLMS field may overlap end of DESC **. mercury lamp, and developed with a 8% aqueous sodium tertiary phosphate solution to obtain a blue, sharp positive image. The plate having the positive image was found to be useful wash off film for various techniques including proof, a title plate for color TV, a title for a motion picture, phototypesetting, instant lettering, typetone and screentone. WHAT WE CLAIM IS:

1. A polymer having recurring structural units of the general formula:

wherein R1 represents a hydrogen atom, or an alkyl or carboxyl group; R2 represents a hydrogen or halogen atom or an alkyl group; R3 represents a hydrogen atom or an alkyl, aryl or aralkyl group; Y represents an arylene group; X represents a divalent organic group connecting the adjacent nitrogen atom and an aromatic ring carbon atom of Y; A represents a group of formula -OCO-C(CN) = CH-Z-N3, wherein Z represents an arylene group; and n represents 0 or 1.

?,. A polymer according to claim 1 wherein X is an alkylene group.

3. A polymer according to claim 2 wherein X is methylene or ethylene.

4. A polymer according to any one of claims 1 to 3 wherein X is

5. A polymer according to any one of claims 1 to 4, wherein A represents a group of formula -OCO-C(CN) = CH-Z-N3 in at least 10 mole % of the total recurring structural units present in the polymers.

6. A polymer according to any one of the preceding claims which also contains recurring structural units of formula (I) in which A represents a hydroxyl group.

7. A polymer according to any one of the preceding claims which also contains structural units derived from addition polymerisation of an ethylenically unsaturated monomer.

8. A polymer according to any one of the preceding claims wherein Y and Z represent an unsubstituted or substituted phenylene group or naphthylene group.

9. A polymer according to claim 8, wherein Y and Z represent a phenylene or naphthylene group.

10. A polymer according to any one of the preceding claims wherein R1 is methyl.

11. A polymer according to any one of the preceding claims wherein R3 represents a hydrogen atom or an alkyl, phenyl or aralkyl group and Y and Z independently represent an unsubstituted or substituted phenylene or naphthylene group.

12. A polymer according to any one of the preceding claims wherein R3 represents phenyl or benzyl.

13. A polymer according to any one of claims 1 to 11 wherein R2 is chlorine or bromine and R2 and R3 are methyl or ethyl.

14. A polymer according to any one of claims 1 to 8 and 10 to 13 wherein Y is cyano, methyl and/or methoxy substituted phenylene and Z is phenylene or naphthylene substituted with nitro and/or chlorine.

15. A polymer according to any one of claims 1 to 8 and 10 to 13 wherein Y is naphthylene substituted with a sulfonic acid.

16. A polymer specifically hereinbefore identified as (1) to (13).

17. A photosensitive composition which comprises a polymer as claimed in any one of the preceding claims and an organic solvent.

18. A composition according to claim 17 which comprises an alkali-soluble resin.

19. A composition according to claim 17 or 18 which comprises cellulose methyl ether and/or cellulose ethyl ether.

20. A composition according to any one of claims 17 to 19 wherein the polymer is one claimed in claim 11.

21. A composition according to any one of claims 17 to 20 which comprises 1-azidopyrene.

22. A composition according to claim 17 substantially as described in any one of Examples 1 to 6.

23. A process of producing an image in a polymeric material, which process comprises imagewise exposing a layer of a polymer as claimed in any one of claims 1 to 16 carried on a support, to a photosensitising radiation and developing the resultant latent image.

24. A process according to claim 23 wherein the polymer is one claimed in claim 11.

25. A process according to claim 23, substantially as described in any one of Examples 1

to 6.