GB1603909A - Radiationsensitve polymers and the preparation thereof - Google Patents

Description

(54) RADIATION-SENSITIVE POLYMERS AND THE PREPARATION THEREOF (71) We KODAK LIMITED, a Company registered under the Laws of England, of Kodak House, Station Road, Hemel Hempstead, Hertfordshire, 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: The invention relates to radiation-sensitive polymers and the preparation thereof.

More particularly, the invention provides polymers suitable for use in radiation-sensitive compositions which can be imagewise exposed to radiation and developed to form, for example, a lithographic printing plate or a resist image. The polymer of the invention is capable of being polymerized or crosslinked on exposure to radiation of a suitable wavelenth to render the polymer insoluble or less-soluble in a solvent for the polymer.

Advantageously, the polymer may be developed using water or an aqueous solution. The polymer may be soluble and/or swellable in the developer. Because of the toughness and resistance to solvents of the compositions when cured by exposure to radiation, they may be used for a variety of surface coating applications.

In accordance with the invention there is provided a radiation-sensitive polymer containing repeating units having the formula:

R represents -H or -CH3; Rl represents -H, an alkyl group or an aryl group; A represents an alkylene group; an oxyalkylene group

or CONH(CH2)HNOCCH2-; Q represents atoms which complete a 5-membered ring; D represents an alkylene group; an oxyalkylene group; -CH2COOCH2CH2OOC-; CH2CONH(CH2)HNOC-; - (CH2)OOC-; or

a represents 1, 2 or 3; b represents 2 or 3; x represents 0 or 1; y represents 0 or 1; and Ze is an anion.

Preferably, the 5-membered quaternary nitrogen-containing ring is derived from N-vinylimidazole or a substituted N-vinylimidazole.

The polymer may be a homopolymer or a copolymer. A comonomer may be required to confer particular properties to the polymer e.g. to make the polymer film-forming or to provide the polymer with a desired degree of water insolubility. In the manufacture of lithographic printing plates, it is necessary for the photohardened polymer to be hydrophobic so that it is ink-receptive. It may be advantageous for the polymer to be a copolymer where the comonomer is used to provide the hydrophobic-hydrophilic balance required of the polymer before and after it is further polymerised or crosslinked.

A comonomer may be used which provides the polymer with repeating units having the formula

wherein R represents -H or -CH3; and X represents a phenyl group; -CN; -COOR3; or

R3 represents an alkyl group slaving trom I to 4 caroon atoms; ana, R4 and Rg, independently, represents -H or an alkyl group having from 1 to 4 carbon atoms.

Suitable comonomers which may be employed include lower alkyl acrylates and methacrylates, e.g. methyl methacrylate; styrene; acrylonitrile and methacrylonitrile; N-alkyl acrylamides and methacrylamides, e.g. isopropylacrylamide. Another type of suitable comonomer is a vinyl alkyl ether.

The proportion of comonomer employed may be varied in order to provide the polymer with the optimum properties. For example, in the preparation of a methylmethacrylate-Nvinylimidazole prepolymer represented by repeating units of the formula:

the ratio of x:y was varied to find the ratio which provided the quaternized polymer with the best properties. It was found that when x:y is greater than 3:1 the quaternized polymer is too insoluble for development while if x:y is greater than 1:4 the polymer is too soluble. An x:y ratio in the region of 1:1 proved most satisfactory.

A prepolymer used in the preparation of the quaternary nitrogen-containing polymer will not usually possess the water-developable property of the quaternary nitrogen-containing polymer.

The polymers of the invention are of particular value in the formulation of radiation- sensitive compositions which can be imagewise exposed to radiation and developed to form e.g. a lithographic plate or a resist image.

Preferred compositions comprise (a) a polymer of the invention and (b) an initiator comprising (i) a metal carbonyl compound or a metallocene and (ii) a trihalomethane derivative.

The trihalomethane derivate may form part of the polymer i.e. the polymer may contain trihalomethane groups, or it may be a separate compound. When a separate compound is used it is preferably soluble in the composition and non-volatile.

It may be advantageous to use an ethylenically unsaturated trihalomethane derivative which will copolymerize with the polymer on exposure to radiation. Examples of such compounds include

Examples of saturated trihalomethane derivatives which may be used include alkyl esters and amides of tribromoacetic acid and alkyl esters of tribromoethanol. Specific examples include Br3CCH20H Br3CCOOC4H9 Br3CCOO(CH2)1 1CH3 Br3CCH2COO(CH2) 10CH3 Br3CCONHC6H13 Br3CCONH(CH2)11CH3 A copolymerizable trihalomethane derivative may be employed in an amount of from 5 to 80 percent by weight based on the weight of the polymer. Preferably, the trihalomethane derivative is employed in an amount of from 5 to 20 percent by weight.

Suitable metal carbonyl and metallocene compounds include those disclosed in U.K.

Patent Specifications Nos. 1,463,816 and 1,495,529, respectively.

A particularly suitable metal carbonyl compound is that represented by the formula ArM(CO)3 wherein Ar represents a six electron doner ligand e.g. benzene, and M represents a metal of Group VIa of the Mendeleeff periodic table e.g. chromium.

The metal carbonyl or metallocene compound may be used in an amount of from 1 to 20 percent, preferably 2 to 5 percent, by weight based on the weight of the polymer.

The composition may also comprise one or more copolymerizable monomers. These may be employed in an amount of from 5 to 80 percent, preferably 10 to 20 percent, by weight based on the weight of the polymer. Suitable monomers include those disclosed in U.K.

Patent Specification No. 1,463,816.

Conventional additive such as dyes, pigments, plasticizers and thermal polymerization inhibitors may also be present in the composition.

The polymers of the invention may be used for the preparation of a radiation-sensitive material comprising a support coated with a layer of a polymer composition described above. The material may be prepared by coating a support with a solution of the polymer composition and evaporating the solvent. It may be advantageous for the coating solution to be an aqueous solution. The coating solution may be applied by a wide variety of techniques including whirler coating and dip coating.

Suitable supports include those made of metal, plastics, glass and paper.

Preferably, the support is a lithographic support, e.g. an aluminium foil.

The coating may be continuous or discontinuous e.g. in a pattern.

Activating radiation may be applied uniformly to the radiation-sensitive material to insolubilize all the polymer present or it may be applied selectively to insolubilize only certain areas of the coating. Thus, for example, in the preparation of photoresists or lithographic printing plates a suitable coated support is imagewise exposed to radiation.

The radiation used to insolubilize the polymers of the invention may be electromagnetic or particle radiation. For example, light, an electron beam or X-rays may be used.

Generally, the polymer may be sensitized, if necessary, to the type of radiation employed.

In a preferred application, a radiation-sensitive polymer of the invention may be used to prepare a lithographic printing plate. Such a plate may be produced by a process which comprises imagewise exposing the material to radiation for a time sufficient to polymerize or crosslink the polymer in the image areas and removing the unexposed polymer with an aqueous solution.

U.V. light may be used to imagewise expose the material.

The polymers of the invention may be prepared by a process which comprises quaternizing a polymer comprising umts containing a 5-membered tertiary nitrogencontaining ring with an ethylenically unsaturated quaternizing agent.

The reaction may be carried out by heating the polymer and the quaternizing agent together in an organic solvent e.g. methanol or dimethyl formamide.

The reaction may conveniently lie carried out at a temperature of from 60 to 100"C.

Preferably, the polymer and quaternizing agent are used in stoichiometric proportions.

Preferably, the polymer is derived from N-vinylimidazole or a substituted N vinylimidazole. The polymer may be a copolymer e.g. copoly(methylmethacrylate, N-vinylimidazole).

The quaternizing agent may be an ethylenically unsaturated halide e.g. vinylbenzyl chloride and chloromethylcarbonyloxyethylmethacrylate.

The polymers of the invention may also be prepared by a process which comprises quaternizing an ethylenically unsaturated 5-membered tertiary nitrogen-containing ring compound with a polymeric quaternizing agent.

The reaction may be carried out by heating the ring compound and the quaternizing agent together in an organic solvent.

The reaction may conveniently be carried out at a temperature of from 60 to 100"C.

Preferably, the tertiary nitrogen-containing compound and the quaternizing agent are used in stoichiometric proportions.

The quaternizing agent may be a polymer having halogen-substituted side chains.

Preferred quaternizing agents include chloroacetic acid esters of hydroxyl-containing monomers. Another preferred quaternizing agent is poly(chloromethylstyrene).

The invention is further illustrated by way of example as follows: EXAMPLE 1 Copoly (methylmethacrylate, N-vinylimidazole) Dioxan was purified by column chromatography on active neutral alumina.

Freshly distilled methylmethacrylate (20 g) and N-vinylimidazole (18.8 g B.A.S.F., distilled 194"C/760 mm) were placed in a 500 ml three-necked round bottomed flask, fitted with a stirrer, nitrogen inlet and a condenser. Dioxan (200 ml) was added and the flask was placed in a thermostated oil bath at 900C. Nitrogen was bubbled through the flask and stirring was started. Azodi-isobutyronitrile (A.I.B.N.) (0.38 g) was added. Stirring and heating was continued for 20 hours. During this time the polymer began to precipitate. The polymer was then obtained by precipitating it from the latex-like dispersion into ether (2 P).

The solid was washed well with ether, and dried under vacuum at room temperature. The polymer had a log viscosity number 21 (methanol at 250C). Yield (30 g).

(CloHl4N2 2)n Requires: C, 61.85; H, 7.22; N, 14.43% Found: C, 58.4; H, 7.1; N, 12.8% EXAMPLE 2 Copoly (methylmethacrylate, vinylbenzylimidazolium) chloride The copolymer of Example 1(9.7 g) was dissolved in methanol (100 ml) by heating to reflux on the steam bath. Vinylbenzyl chloride (7.6 g Dow Chemical, 40% p and 60% m isomer b.p. 60"C/2 mm) was added, followed by 'Topanol OC' Trade Mark of I.C.I.

Limited (0.2 g). The solution was heated under reflux for 20 hours and the polymer was isolated from the solution by precipitation into ether (2e). The polymer was washed with ether, filtered and dried under vacuum. Yield (10 g). Log viscosity number 48 (methanol at 25"C).

(ClgH23CtN202)n Requires: N, 8.1; C, 10.24% Found: N, 8.4; C, 9.7% EXAMPLE 3 N- (2- Tribromomethylcarbonyloxypropyl) methacrylamide N-(2-Hydroxypropyl)methacrylamide (7.15 g) was dissolved in dichloroethane (150 ml) in a 500 ml three-necked round bottomed flask, fitted with a stirrer, two dropping funnels and a nitrogen supply. The flask was cooled to 0 C by means of an ice/salt freezing mixture, stirring was started and the reaction was blanketed with dry nitrogen. 'Topanol OC' (0.1 g) was added. Tribromoacetylbromide (18 g) was added dropwise, simultaneously with triethylamine (5.1 g) over a period of 30 minutes, keeping the temperature between 0 and -5"C. While stirring the mixture was then slowly allowed to come to room temperature.

After four hours the precipitated salts were filtered off, washed with dichloroethane, and the washings and filtrate were combined. The solvent was removed under vacuum by a rotary evaporator leaving an oily residue. This was dissolved in a mixture of water and ethanol and on standing the product crystallized as a colourless solid. It was recrystallized from the same solvent mixture.

Yield (13 g) m.p. 104-105"C.

EXAMPLE 4 A coating composition was made up as follows: Polymer described in Example 2 1 g Monomer described in Example 3 0.8 g Benzene chromium tricarbonyl 0.05 g in 0.5 ml acetone n-Propanol 10 ml The above solution was coated onto a 5" x 5" grained phosphoric acid anodised aluminium foil, which was unsubbed, on a whirler coating machine at 150 rpm. The plate was spun for two minutes at room temperature and eight minutes at 300C.

Part of the plate was then exposed in a vacuum frame, through a 0.15 density increment step tablet, to four 125w high pressure mercury vapour lamps at a distance of 18 inches for five seconds.

The exposed coating was then developed in demineralized water. After removal of the unexposed areas, the non-image areas were desensitized with Kodak Polymatic Desensitizer Gum solution. The plate was then given a further wipe with a cotton pad damped with deionized water and the plate was inked. The last step to mk-up solidly was recorded as ten.

EXAMPLE 5 A coating composition was made up as follows: Polymer described in Example 2 1 g Monomer described in Example 3 0.8 g Methylene bisacrylamide 0.8 g Benzene chromium tricarbonyl 0.05 g n-Propanol 10 ml Deionized water 5 ml The procedure of Example 4 of coating, exposure and development was then carried out except the exposure time was increased to thirty seconds. After removal of the unexposed areas with demineralized water, the non-image areas were desensitized with Kodak Polymatic Desensitizer Gum solution. The plate was then inked and the last step to ink-up solidly was recorded as eleven.

EXAMPLE 6 Trichloromethylcarbonyloxyeth Imethacrylate Hydroxyethylmethacrylate (13.0 g) was placed in a 250 ml, three necked, round bottomed flask, fitted with a stirrer, air condenser and two dropping funnels, as well as a thermometer. The apparatus was placed in an ice/salt freezing bath. Dichloroethane (100 ml) was added, followed by the simultaneous dropwise addition of triethylamine (10.1 g) and trichloroacetyl chloride (18.2 g). During the addition the temperature was not allowed to rise above 2"C. After the addition was complete, the mixture was stirred for a further 6 hours, during this time the temperature rose gradually to room temperature. The mixture stood overnight, and the precipitated salt was filtered off, and the residue was washed thoroughly with dichloroethane. The washings and the filtrate were combined and the solvent was removed on a rotary evaporator. The residue still contained some solid. It was dissolved in ether, the ether solution was washed with water (3 times). The solution was then dried (MgSO4), filtered, and the solvent was removed under vacuum. The residue was distilled under high vacuum, collecting the fraction, boiling between 84-90"C/0.1 mm (16 g).

C8HgCt304 Require: C, 34.84; H, 3.25; Ct,38.65% Found: C, 35.5; H, 3.4; C, 40.3% EXAMPLE 7 Chloromethylcarbonyloxyethylmethacrylate The method of preparation was similar to that described in Example 6. Hydroxyethylmethacrylate (39 g) was dissolved in dichloroethane (250 ml), in a 1 e three necked, round bottomed flask, fitted with a stirrer, two dropping funnels, an air condenser, connected to a nitrogen supply, and a thermometer. With ice/salt cooling, triethylamine (30.3 g) and chloroacetyl chloride (33.9 g) were added simultaneously at such a rate that the temperature did not rise above 5"C in a nitrogen atmosphere. The mixture was then stirred overnight at room temperature, the triethanolamine hydrochloride which had Precipitated was filtered off and washed with dichloroethane. The washings and the filtrate were combined, and the solvent was removed on a rotary evaporator. 'Topanol OC' (0.1 g) was added to the residue, which was distilled under high vacuum, the fraction boiling between 80-94"C/0.1 mm was collected. It was redistilled, after the addition of a further quantity of 'Topanol OC' (0.1 g), collecting the fraction boiling at 90"C/0.1 mm (30 g).

C8H1lCtO4 Require: C, 46.48; H, 5.33; C, 17.19% Found: C, 48.48; H, 5.72; C, 15.5% EXAMPLE 8 N- (2-Chloromethylcarbonyloxypropyl)methacrylamide The compound was prepared by the method described in Example 7, using N- (2- hydroxypropyl)methacrylamide (14.3 g), dichloroethane (200 ml), chloroacetyl chloride (11.3 g) and triethylamine (10.1 g). The product distilled at 1120C/0.1 mm (12 g) and was obtained as a viscous oil.

C9HI4CtNO3 Require: C, 49.20; H, 6.38; C, 16.17; N, 6.38% Found: C, 49.62; H, 6.70; C, 15.95; N, 6.68% EXAMPLE 9 Poly (ethylmethacrylate) -co- (N-vinylimidazole) A 250 ml three necked, round bottomed flask, fitted with a stirrer, condenser and nitrogen inlet was placed in a thermostated oil bath, set at 900C. Ethyl methacrylate (11.4 g) and N-vinylimidazole (18.8 g) together with dioxan (purified, see Example 1; 75 ml) were placed in the flask. Nitrogen was bubbled through the flask, stirring was started, and A.I.B.N. (0.15 g) was added. After heating for two and a half hours, a further quantity of ethyl methacrylate (11.4g) and N-vinylimidazole (9.4 g), A.I.B.N. (0.075 g) and dioxan (25 ml) was added. Heating was continued overnight. Ethanol was then added to the milky solution and the polymer was isolated by precipitation into ether. It was washed with ether, and dried under vacuum (38 g).

(CllHl6N202)n Require: C, 62.50; H, 7.69; N, 13.46% Found: C, 60.71; H, 7.28; N, 15.7% EXAMPLE 10 Poly(methylmethacrylate)-co-(2-methyl-N-vinylimidazole) The method of Example 1 was followed, using methylmethacrylate (10 g) and 2-methyl-N-vinylimidazole (10.8 g), together with A.I.B.N. (0.10 g) in dioxan (100 ml).

The polymer was isolated by precipitation into ether, and dried under vacuum (15 g).

(CllH16N202)n Required: N, 13.46% Found: N, 11.74% N.M.R. spectroscopic analysis showed that the ratio of methyl methacrylate to 2-methyl-1-vinylimidazole was 1.3:1.

EXAMPLE 11 Poly (ethylmethacrylate) -co- (2-methyl-N-vinylimidazole) Again, the method of Example 1 was followed using, ethyl methacrylate (11.4 g) and 2-methyl-N-vinylimidazole (10.8 g), A.I.B.N. (0.11 g) and dioxan solvent (100 ml). The polymer was isolated as before (14 g).

(Cl2Hl8N202)n Require: N, 12.62% Found: N, 9.4% EXAMPLE 12 Poly (methylmethacrylate) -co- (chloromethylcarbonyloxyethylmethacrylate) The method of Example 1 was used, with the following monomer charge: Methylmethacrylate 5.0 g Chloromethylcarbonyloxyethyl methacrylate 10.32 g A.I.B.N. 0.076 g Dioxan 75 ml Yield = 10 g.

(C13H19CO6)n Require: C, 11.58% Found: C, 9.4% EXAMPLE 13 Poly (chloromethylstyrene) Vinylbenzyl chloride (40/60 p-, m-mixture, Dow Chemical 97% pure by GLC; 0.2 mole, 30.5 g) was dissolved in benzene (Na dry, 250 ml) together with azo-bis-isobutyronitrile initiator (1 mole %, 0.33 g), and the mixture was stirred at the reflux temperature under N2 for about 20 hours. The polymer was then precipitated into methanol, the solid was filtered off and dried under vacuum to give 17 g (56% yield) of a white powder.

(CsHsct)n Requires: C, 71.10; H, 5.96; C, 23.25% Found: C, 71.14; H, 6.08; C, 23.55% EXAMPLE 14 Quaternization of Polymer of Example 9 with Chloromethylstyrene Copolymer Example 9 (10.4 g) was dissolved in DMF (100 ml). The solution in a 250 ml round bottom flask was placed in a thermostated oil bath held at 95"C. Chloromethyl styrene (Dow, 7.5 g) was added. After heating overnight, the polymer was isolated from the solution by precipitation into ether. The polymer was dried under vacuum and then dissolved in methanol. The solid polymer was isolated from this solution by reprecipitation into ether. It was collected and dried under vacuum (12 g).

(C20H2sctN2o2)n Require: C, 9.85% Found: C, 9.0% EXAMPLE 15 Quaternization of Polymer of Example 10 with Chloromethylstyrene The method of Example 14 was employed, using the same quantities but employing the copolymer of Example 10. The polymer was isolated as described in Example 14 (14 g).

(C20H25CtN2O)n Require: C, 9.85% Found: Ce, 8.83% EXAMPLE 16 Quaternization of Polymer of Example 10 Chloromethylcarbonyloxyethylmethacrylate Again, the method of Example 14 was followed. The following materials were used: Copolymer, Example 10 10.4 g Chloromethylcarbonyloxyethyl- 10.3 g methacrylate DMF 100 ml The polymer was isolated as before (15 g).

(C19H27ClN2O6)n Require: Ce, 8.56% Found: ce, 7.70% EXAMPLE 17 Quaternization of Polymer of Example 12 with N-vinylimidazole The method of Example 14 was employed, using the following charge: Copolymer, Example 12 7.66 g N-Vinylimidazole 2.3 g DMF 75 ml The polymer was isolated as in Example 14. It was redissolved in ethanol and reprecipitated in ether (7 g).

(C18H25CN206)n Require: ce, 9.09% Found: Ce, 7.30% EXAMPLE 18 Quaternization of Polymer of Example 11 with Chloromethylcarbonyloxyethylmethacrylate The method of Example 14 was used, and the charge was as follows: Copolymer, Example 11 11.1 g Chloromethylcarboxyethyl- 10.3 g methacrylate DMF 100 ml Yield of polymer (16 g) (Cl8H27CtN204)n Require: Ce, 9.58% Found: ce, 6.9% EXAMPLE 19 Quaternization of Polymer of Example 13 with N-vinylimidazole Poly(vinylbenzyl chloride) (3.3 x 10-2 mole, 5.1 g) and 1-vinylimidazole (1.6 x 10-2 mole, 1.5 g) were dissolved in dimethyl formamide (100 ml) and the mixture was kept stirring at 80"C for 18 hours. A white precipitate formed in the reaction mixture during that time. The mixture was rendered homogeneous by adding methanol (50 ml), and the final polymeric product was isolated by precipitating into ethyl acetate (about 2t). The solid was filtered and then dried under vacuum to give 6 g of a white powder, soluble in water and methanol. The overall yield was 91%.

(C4H9Ce co-(Cl4H15CtN2)1 Requires: C, 67.38; H, 5.91; N, 6.83% Found: C, 64.43; H, 6.01; N, 6.84% EXAMPLE 20 A coating composition was made up as follows: Polymer described in Example 19 5.0 g Monomer described in Example 3 4.25 g Mesitylene chromium tricarbonyl 1.25 g Acetone 6.25 ml Methanol 56.25 ml The mesitylene chromium tricarbonyl was dissolved in a mixture of 6.25 ml acetone and 6.25 ml methanol. This was then added to a solution of the other constituents in the remainder of the methanol. The resulting solution was then coated onto a 10" x 15" phosphoric acid anodised aluminium foil at 120 rpm. The procedure of drying, exposure and development used in Example 4 was then carried out except that the exposure time was increased to 60 seconds. After development the non-image areas were desensitized with Kodak Polymatic Plate Finisher, and then 30,000 prints were obtained on an A.B. Dick 350 press. The last step to ink-up solidly was recorded as six, and no sign of wear was seen on the plate at the end of the run.

EXAMPLE 21 Coating compositions were made up as follows, using polymers listed below: Polymer 1 g Monomer described in Example 3 0.2 g Benzene chromium tricarbonyl 0.05 g Orasol Red B (CIBA) 0.02 g Leuco propyl violet 0.04 g Methylethyl ketone 8 ml Methanol 4 ml The procedure of Example 4 of coating, exposure and development was carried out except that the whirler speed was descreased to 120 rpm, and the exposure time was increased to 60 seconds. After desensitization of the non-image areas with Kodak Polymatic Plate Finisher, the image areas were inked. The last step to ink-up solidly was recorded as in the following list.

Last Step to Ink-Up Solidly Polymer described in Example 14 9 Polymer described in Example 15 9 Polymer described in Example 16 5 Polymer described in Example 17 4 Polymer described in Example 18 5 Polymer described in Example 19 7.

Addition of leuco propyl violet provided the layers with a "print-out" image which was visible after exposure. Addition of Orasol Red B provided a red colour to the layers which was retained in image areas after development.

EXAMPLE 22 A coating composition was made up as follows: Polymer described in Example 19 1 g Monomer described in Example 6 0.2 g Benzene chromium tricarbonyl 0.05 g Methanol 4 ml Methyl ethyl ketone 8 ml The procedure of Example 4 of coating, exposure and development was then carried out except the exposure time was increased to 60 seconds. After desensitization with Kodak Polymatic Plate Finisher the image areas were inked and the last step to ink-up solidly was recorded as four.

EXAMPLE 23 Preparation of Tribromomethylcarbonyloxyethylmethacrylate The method described in Example 6 was followed using the following charge.

Hydroxyethylmethacrylate 13 g Triethylamine 10.2 g Dichloroethane 190 ml Tribromoacetyl bromide 36 g After the final removal of the solvent, the product was used without distillation. It was a pale straw coloured liquid.

C8HgBr304 Require: C, 23.47; H, 2.20; Br 58.67% Found: C, 26.90; H, 2.90; Br 56.7% EXAMPLE 24 Preparation of N-(2-chloromethylforrnamidoethyl)methacrylamide 2-Aminoethylmethacrylamide hydrochloride (16.4 g) was dissolved in water (50 ml) and sodium hydroxide solution (40 ml; 10% w/v) was added. With stirring and cooling in an ice bath, chloroacetyl chloride (11.3 g) in toluene (30 ml) was added dropwise and simultaneously with enough 10% w/v sodium hydroxide solution to keep the solution at pH 8. A solid began to precipitate. Stirring the mixture was continued for two hours and it was then refrigerated overnight. The product was then filtered, washed with water and dried under vacuum (11.5 g) m.p. 126-128"C.

CsH13CN2O2 Require: C, 46.94; H, 6.35; C, 17.36; N, 13.69% Found: C, 46.63; H, 6.60; C, 17.20; N, 13.20% EXAMPLE 25 Quaternization of Polymer of Example 10 with N-(2-chloromethylformamidoethyl)methacrylamide The method of Example 14 was followed by using the following charge: Polymer, Example 10 10.4 g D.M.F. 100 ml N-(2-chloromethylcarbonamido ethyl)methacrylamide 10.2 g Yield: 16 g (C19H29CeN4041 Require: C, 55.26; H, 7.03; Ce 8.61; N, 13.56% Found: C, 52.25; H, 6.89; ce 7.26; N, 12.73% EXAMPLE 26 Poly (methylmethacrylate) -co- (n-vinylimidazole) (a) Monomer feed ratio 1:1. Methylemethacrylate (20 g) and N-vinylimidazole (18. 8g) were dissolved in a 3:1 v/v mixture of ethanol and acetone (150 ml) in a 500 ml 3 necked round bottomed flask, fitted with a magnetic stirrer, a nitrogen inlet tube dipping below the surface of the liquid, and a condenser. The apparatus was placed in a thermostated oil bath set at ID=12.

(c) Monomer feed ratio 2:3. The method for preparation (a) was followed except that the following charge was used: Methyl methacrylate 20 g N-vinylimidazole 28.2 g A.I.B.N. 0.24 g Ethanol/acetone 3:1 v/v mixture 160 ml 26 g of a colourless powder were obtained.

(C25H34N6O4) Require: C, 62.24; H, 7.54; N, 17.42% (C15H22N204) Require: C, 61.22; H, 7.48; N, 9.52% Found: C, 59.61; H, 7.34; N, 10.65% N.M.R. spectroscopy analysis gave a monomer ratio of 1.8:1.

EXAMPLE 27 Quaternization of polymers (a), (b) and (c) of the above Example with chloromethylcarbonyloxyethylmethacrylate The method of Example 14 was applied but the following amounts were used: (a) (b) (c) Polymer 9.7 g 10 g 9.7 Chloromethylcarbonyl oxyethylmethacrylate 10.3 g 10.3 g 12.35 D.M.F. 100 ml 100 ml 100 ml Yields 13 g 17 g 16.7 g % Ct found 6.55% 8.03% 7.59% EXAMPLE 28 Poly (acrylonitrile)-co- (N-vinylimidazole) Acrylonitrile (10.6 g), and N-vinylimidazole (18.8 g) were dissolved in dioxane (75 ml) in a 250 ml, 3 necked round bottomed flask, fitted with a magnetic stirrer, nitrogen inlet and a reflux condenser. The apparatus was placed in a thermostated oil bath set at 65"C and nitrogen was bubbled continuously through the solution. A.I.B.N. (0.14 g) was added.

After 30 minutes, the polymer began to precipitate. After 4 hours the reaction was stopped, the precipitated polymer was filtered, and thoroughly washed with ether. The polymer was then collected and dried under vacuum (25 g).

(CsH9N3)n Require: C, 65.3; H, 6.12; N, 28.57% Found: C, 62.42; H, 6.1; N, 25.60% N.M.R. spectroscopy analysis showed that the ratio of acrylonitrile to N-vinylimidazole was 1:1.

EXAMPLE 29 Quaternization of Poly (acrylonttrile) -Co- (N-vinylimidazole) with chloromethylcarbonyloxyethylmethacrylate The method of Example 14 was employed using the following charge.

Poly(acrylonitrile)-co-(N-vinylimidazole) 7.4 g Chloromethylcarbonyloxyethylmethacrylate 10.3 g D.M.F. 75 ml The quaternized polymer (12 g) was a colourless powder.

(C16H20CtN304)n Require: C, 54.31; H, 5.65; Ct, 10.04; N, 11.88% Found: C, 51.60; H, 5.85; ce, 9.36; N, 11.67% The following compounds are bromine derivatives which are not unsaturated and which can be used in the process.

EXAMPLE 30 n-Butyltribromoacetate n-Butanol (7.4 g) and tribromoacetic acid (29.6 g) were dissolved in toluene (100 ml).

lfrToluenesulphonic acid (0.7 g) was added, and the solution was heated under reflux in a Dean and Stark apparatus. After 90 minutes water (2 ml) had been collected. The solvent was spun off on a rotary evaporator and the residue was distilled under water pump vacuum, collecting the fraction boiling between 120-130"C. The fraction was redistilled yielding a colourless oil b.p. 128"C/15-18 mm (31 g).

(C6H9Br3o2) Require: C, 20.39; H, 2.55; Br, 67.99% Found: C, 20.42; H, 2.48; Br, 67.40% EXAMPLE 31 n-Lauryltribromoacetate This was prepared by the same method as described for n-butyltribromoacetate.

Dodecanol (18.8 g), tribromoacetic acid (29.7 g) and p-toluenesulphonic acid (1 g) were used. The product was distilled twice under high vacuum yielding a colourless oil, b.p.

150-154"C/0.05 mm.

C14H25Br302 Require: C, 36.13; H, 5.37; Br, 51.61% Found: C, 36.84; H, 5.54; Br, 47.86% Our co-pending Patent Application No. 25437/78 (Serial No 1603908) describes and claims a radiation-sensitive composition comprising a) a polymer comprising units containing a quaternary nitrogen atom and an ethylenically unsaturated group; and b) an initiator comprising fi) a metal carbonyl compound or a metallocene and (ii) a trihalomethane derivative.

Claims (17)

WHAT WE CLAIM IS:

1. A radiation-sensitive polymer containing repeating units having the formula:

R represents -H or -CH3; R1 represents -H, an alkyl group or an aryl group; A represents an alkylene group; an oxyalkylene group;

or -CONH(CH2)bHNOCCH2-; Q represents atoms which complete a 5-membered ring; D represents an alkylene group; an oxyalkylene group; -CH2COOCH2CH2O C-; -CH2CONH(CH2)bHNOC-; - (CH2)OOC-; or

a represents 1, 2 or 3; b represents 2 or 3; x represents 0 or 1; y represents 0 or 1; and Z- is an anion.

2. A polymer as claimed in claim 1 wherein the quaternary nitrogen-containing ring is derived from N-vinylimidazole or a substituted N-vinylimidazole.

3. A polymer as claimed in claim 1 or claim 2 which is a homopolymer or a copolymer.

4. A polymer as claimed in claim 1 or claim 2 which is a copolymer containing repeating units having the formula

wherein R represents -H or -CH3; and X represents a phenyl group; -CN; -COOR3; or

R3 represents an alkyl group having from 1 to 4 carbon atoms; and, R4 and R5, independently, represents -H or an alkyl group having from 1 to 4 carbon atoms.

5. A polymer as defined in claim 1 substantially as hereinbefore described in any one of Examples 2, 14 to 19, 25, 27 and 29.

6. A process for preparing a polymer as claimed in claim 1 which process comprises quaternizing a polymer comprising units containing a 5-membered tertiary nitrogencontaining ring with an ethylenically unsaturated quaternizing agent.

7. A process as claimed in claim 6 wherein the polymer and the quaternizing agent are heated together in an organic solvent.

8. A process as claimed in claim 6 or claim 7 wherein the polymer is derived from N-vinylimidazole or a substituted N-vinylimidazole.

9. A process as claimed in any one of claims 6 to 8 wherein the quaternizing agent is an ethylenically unsaturated halide.

10. A process as claimed in claim 6 substantially as hereinbefore described in any one of Examples 2, 14 to 16, 18, 25, 27 and 29.

11. A process for preparing a polymer as claimed in claim 1 which process comprises quaternizing an ethylenically unsaturated 5-membered tertiary nitrogen-containing ring compound with a polymeric quaternizing agent.

12. A process as claimed in claim 11 wherein the ethylenically unsaturated 5-membered tertiary nitrogen-containing ring compound and the quaternizing agent are heated together in an organic solvent.

13. A process as claimed in claim 11 or claim 12 wherein the ring compound is N-vinylimidazole or a substituted N-vinylimidazole.

14. A process as claimed in any one of claims 11 to 13 wherein the quaternizing agent is a polymer having halogen-substituted side chains.

15. A process as claimed in claim 14 wherein the quaternizing agent is poly(chloro methylstyrene).

16. A process as claimed in claim 11 substantially as hereinbefore described in Example 17 or Example 19.

17. A polymer whenever prepared by a process as claimed in any one of claims 6 to 16.