NO137104B - LIGHT-SENSITIVE POLYMER REST. - Google Patents

Description

The present invention relates to new light-soluble polymer esters.

The light-sensitive materials, which are known as photopolymers,

are well known and used e.g. as covering agents in photomechanical processes such as the production of nameplates and plates with printed circuits and in the production of printing plates where the exposed and photohardened areas make up the printed image. Such materials exhibit two common undesirable typical features, namely that no change in color is obtained upon exposure, and that the addition of a usually expensive "super-sensitizer" is required to improve the spectral sensitivity thereby achieving

an acceptable exposure time to a light source common in the industry,

e.g. by exposure in e.g. ten minutes in a carbon arc-

lamp or a pulsating xenon lamp. The prior art can be exemplified by (i) the material known as "Kodak Photo Resist" (R.T.M.) which is believed to be poly(vinylcinnama-t} and which is described inter alia in British Patent No. 695,197? and for which suitable super-sensitizers are described in British Patent No. 743,455 (e.g. the addition of 3-methyl-2-benzoyl-1-methylidene-3-naphthothiazoline as a super-sensitizer increases the speed 700 times)5 (ii) "Kodak Ortho Resist" (R.T.M. ) believed to be poly(vinylcinnamylidene acetate) super-sensitized with a pyrylium salt and described in British Patent No. 949,919; and (iii) polymeric cinnamoylated epoxy resins according to British Patents No. 794,572, No. 913,764 and No. 921,530 where 4.4 '-bis (dimethylamino) benzophenone is used as a supersensitizer.

As indicated above, layers of these materials do not change color upon exposure, although this is a very highly desired property of e.g. the copying work or how many different negative copying templates are used for exposure of different areas. Attempts that have previously been made by adding photochromic materials to make visible the areas that have been exposed to light have failed due to

that in that case a sufficient amount has been added to produce a color change, which can be seen in the non-actinic light at the workplace, then the additive has modified the exposed area so as to affect its developing property or its value or affect it as a printed image. This is probably due to dissolution of the photochromic materials either in the developer or in the etchant or in the printing ink, depending on the conditions, and which makes the photoresist ("photoresist") porous. The same effect has been found in some cases when the supersensitizer is leached from the image area.

It has now been found that certain polymer esters have the desirable properties of producing a good change of color upon exposure, and which are in themselves so fast-acting that under normal conditions there is no need for a supersensitizer, even if such a sensitizer can be added if desired and leave e.g. a "camera-fast" printing plate blank. Photo-masking agents, which are made from these esters, do not have degraded properties as they show resistance to etching agents, and have a long service life on a printing press.

According to the present invention, a light-sensitive polymer ester has been provided which is a polymeric polyhydroxy material which is corested with an acid with the formula:

where a and b mean 0 or 1 and a + b means at least 1,

R is a phenyl group optionally substituted with a

or more halogen atoms, alkyl groups or alkoxy groups; and R^, R2, R^ and R^, which may have the same or different meanings, mean halogen atoms, hydrogen atoms, cyano groups, alkyl groups, aryl groups, alkoxy groups, aryloxy groups, aralkyl groups or aralkyl groups, provided that at least one of the groups R^ to R ^ means a halogen atom or a cyano group

Light-soluble resin esters of azido-substituted aromatics

acids are described in the literature, e.g. epoxy resin azidobenzoates in English patent 1,118,213 and the corresponding azidocinnamates in Czech patent 135,029, but these known esters only give a rather weak change in color upon exposure and need the addition of the supersensitizer to achieve an acceptable exposure rate. It was therefore not to be expected that the products according to the present invention would provide the desired properties, and furthermore it was not to be expected that this could not be achieved without at the expense of their properties as photocover agents.

According to one embodiment, the light-sensitive polymer ester according to the invention contains groups with the general formula:

bonded to carbon atoms,

where a means 1$ b means zero or 1-, R, R2, R3 and R4 have the above meanings $ and R^ means a halogen atom or a cyano group. E.g. can in this formula

a and b both mean 1, R may mean a phenyl group, R 1 may mean a chlorine atom, R^ and R^ may mean hydrogen atoms, and may mean a hydrogen atom, a bromine atom, a chlorine atom or a cyano group.

In another embodiment, the light-sensitive polymer ester according to the invention contains groups with the general formula:

bonded to carbon atoms,

where a and b mean zero or 1 and a + b means at least I5

R is a phenyl group substituted with a

group or groups attached to the azido group; and R.

i I R^, R3 and R^, which may have the same or different '. meaning, means halogen atoms, hydrogen atoms, cyano groups, alkyl groups, aryl groups, alkoxy groups, aryloxy groups, aralkyl groups or aralkyl groups, provided that at least one of the groups R^ to R^ means a halogen atom or a cyano group. In this formula, e.g. a means zero, b can mean 1, R^ can mean hydrogen, R^ can mean a bromine atom, a chlorine atom

or a cyano group, and R may also be substituted with a methyl group, a methoxy group, a bromine atom or a chlorine atom.

According to the present invention, the carbon atoms to which the ester groups are bound can be obtained by means of a polyhydroxy material. The polyhydroxy material is preferably an epoxy resin. However, other polyhydroxy materials such as phenoxy resins, poly(vinyl alcohol), cellulose, a cellulose ester or a novolak resin prepared from a phenol as well as formaldehyde can be used. The esters according to the invention can be prepared by reacting at least one acid chloride with the formula:

where a, b, r, R^, R2, R3 and R^ have the aforementioned meaning,

with such a polyhydroxy material. The reaction can take place in the presence of a base, which can be a tertiary amine, which can also serve as a solvent, or also in the presence of other solvents such as dioxane, dimethylformamide, methylene chloride, or methyl ethyl ketone. Suitable tertiary amines are triethylamine, . N-methylpiperidine, pyridine, quinoline, dimethylaniline or their mixtures. The reaction is preferably carried out at 20 to 70°C. Other methods of esterification will be apparent to those skilled in the art.

Particularly useful polyhydroxy materials are epoxy resins, which are obtained by condensation of bisphenol A

and epichlorohydrin and which correspond to the formulas'.

where n preferably means 9 to 12.

Epoxy resins of the above type found to be useful are "Epikote 1007" (R.T.M.). and "Epikote 1009" (R.T.M.). These are commercially available products from Shell Chemical Company, and have the specifications:

The condensation products of epichlorohydrin with other aromatic . hydroxy compounds can be used as polyhydroxy material. Examples of other aromatic hydroxy compounds which may be used include the bisphenols:

4,4'-dihydroxydiphenylmethane

4,4'-dihydroxydiphenyl ether

4,4'-Dihydroxydiphenylsulfone

Suitable acid chlorides are those obtained from the following azido-substituted acids:-

The acid chlorides can be used individually or in admixture with each other and/or in admixture with non-azido group-containing acid chlorides of aliphatic and aromatic carboxylic acids. One can e.g. use acid chlorides for acetic acid,. propionic acid, 2-ethyl-h&xanonic acid and benzoic acid. The reaction of non-azido group-containing acid chlorides with polyhydroxy material can take place not only simultaneously with the reaction of said chloride with the above general formula, but also before or after.

A particularly preferred method for producing esters according to the present invention consists of first dissolving polyhydroxy material, preferably an epoxy resin, in methyl ethyl ketone or dioxane to form a 10 to 40% solution, adding an acid chloride or a mixture of acid chloride and non- azido group-containing acid chloride, either alone or dissolved in methyl ethyl ketone or dioxane, followed by sufficient pyridine to convert all the acid chloride, and there-

after heating the mixture to a temperature between 40 and 60°C for 2 to 4 hours. The reaction mixture is diluted with

1:1 methyl ethyl ketone/toluene, after which one filters to

remove the pyridinium chloride, and the residue is slowly dripped into stirred alcohol. The esters are obtained as a yellow-brown powder.

As already indicated, the esters are according to the present invention

of particular value in the production of photographically produced printing plates and the like. A radiation-sensitive plate, consisting of (i) a substrate of a material to which a film consisting of an ester according to the present invention will adhere, such as glass, paper, resin-impregnated paper, synthetic resin foil or a metal plate such as aluminum, zinc , magnesium and copper;

and (ii) a layer which consists of an ester according to the present invention, and which is carried on the substrate.

In order to apply the layer to the carrier, the light-sensitive material, which must form the layer, is dissolved in a suitable solvent or mixture of solvents, such as dioxane, ethylene glycol, monomethyl ether acetate or ethyl lycol monoethyl ether acetate, and the resulting solution is applied to the substrate in various ways such as by dipping, spraying or centrifugal coating, after which the solvent is evaporated either by air drying or heating. The coating weight per square meter is generally between 0.2 and 2 g.

For coating purposes in industry it may be desirable to

add to the esters according to the present invention one or more of the following ingredients: dye, plasticizers, wetting agents, supersensitizers (as previously mentioned), stabilizers, non-reactive polymers, photosensitive polymers, and also material capable of reacting with the photolyzed acid groups .

After the substrate has been coated with a film of the ester-containing light-sensitive solution, it is dried to form a

light sensitive plate. When using these plates,

the light-sensitive coating is image-wise exposed for a period of time that depends on the composition of the coating, the thickness of the coating, the substrate, the intensity of the light source and the intended product. The unexposed areas will remain soluble and thereby enable development of the image using a suitable solvent or solvent emulsion developer.

The solvent or solvent mixture used

for development of the photographically exposed plate, must

be chosen with care as the solvent or mixture should have a good dissolving effect on the non-exposed areas and at the same time have little effect on the cured image. Suitable solvents include dioxane, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate and tetrahydrofurfuryl acetate.

By adding to the developer poor solvents or non-solvents for the unexposed areas, such as propylene glycol or ethylene glycol monoethyl ether, it is possible to reduce the dissolution rate of the unexposed material and thus facilitate the control of the development.

Preferred areas of application for the light-sensitive materials

and the parts according to the invention are the production of printing plates and the production of etching cover agents. The photopolymers are suitable for other purposes in addition to printing, e.g. production of printed circuits etc., by chemical embossing in the production of decorative effects.

In the production of the new polymer esters, the acid chlorides can be used individually or in admixture with each other and/or in admixture with non-azido group-containing acid chlorides of aliphatic and aromatic carboxylic acids. In the case where non-azido group-containing acid chlorides are used, the formed ester will also contain ester groups derived from such acid chlorides. E.g.

in the case where an acid chloride of acetic acid, propionic acid, 2-ethylhexanoic acid or benzoic acid is used, the ester formed will also contain acetate, propionate, 2-ethylhexanoate or

benzoate groups.

The reaction of non-azido group-containing acid chlorides with the polyhydric alcohol material need not necessarily occur simultaneously with the reaction of the acid chloride with the above-mentioned general formula, but can also occur before or after.

Furthermore, as can be seen from the following examples, the esters according to the invention can also contain non-esterified hydroxyl groups.

The following examples illustrate the invention:

EXAMPLE 1

(a) Preparation of epoxy resin ester of 4-azido-g-cyano-/^-chlorocinnamylideneacetic acid.

2.42 g of 4-azido-(3-chlorocinnamaldehyde (prepared by a modified method described in U.S. Patent No. 3,598,844) was dissolved in 50 mL of glacial acetic acid. 5.4 g of cyanoacetic acid was added and the mixture was heated 2 hours at 80°C, during which time the product separated out as fine needles.After filtration, the product was washed with glacial acetic acid (2x5 ml).

and then dried over sodium hydroxide. This gave 1.4 g of the product. Recrystallization in methanol resulted in dark yellow needles of 4-azido-α-cyano-α-chlorocinnamylideneacetic acid

(III).

4 g of the acid containing the azido group was heated with stirring with 25 ml of redistilled thionyl chloride at reflux temperature for 6 hours. Half of the thionyl chloride was removed by vacuum distillation and the cooled solution was completely converted to petroleum

ether (boiling point range 40-60°C). The acid chloride was precipitated as an orange-coloured powder.

2.00 g (0.01 g equivalents) of "Epikote 1007" was dissolved in 30 ml of dioxane, and 2.93 g (0.01 M) of the acid chloride was added.

After stirring for 10 minutes, 1.0 ml of pyridine was added, and the mixture was heated at 50°C for 4 hours. The pyridinium chloride was filtered off and the solution added dropwise to 400 ml of ethanol. The precipitated resin was filtered off and washed with more ethanol on the filter.

Yield: 3.41 g.

The UV spectrum showed a maximum at 375 nm.

Extinction at 375 nm El, em=510 (dioxane).

(b) Production of a printing plate.

2.5 g of the epoxy resin 4-azido-oc-cyano-9-chlorocinnamylidene acetic acid ester were dissolved in a mixture of equivalent volumes of dioxane and 2-methoxyethyl acetate, whereby a 5% solution was obtained. The solution was diluted with toluene to 2.5%,

and then using a centrifugal machine applied to the surface

to an aluminum plate, which was electro-grained, thereby giving a coating weight of 0.5 g per square meter. After drying, the light-sensitive plate obtained was exposed for 30 s in contact with a negative in the light of a 4,000 watt pulsating xenon lamp at a distance of 0.65 meters. A deep yellow-brown color was induced in the light-affected areas. The exposed plate was developed using a mixture of glycol ester and wetting agent as described in Example 8 of British Patent No. 1,220,808, rinsed with water and a bold printing ink applied.

EXAMPLE 2

(a) Preparation of the epoxy h arpic ester of 4-azido-g-bromo-?»-chlorocinnamylideneacetic acid.

20.7 g of 4-azido-(3-chlorocinnamaldehyde in 200 ml of methylene chloride) was added to a solution of 42.8 g of triphenylcarbethoxybromophosphorane in 200 ml of methylene chloride. The resulting solution was then allowed to stand for 60 hours. The solvent was removed in vacuo at 25° C. and the resulting crystalline mass was extracted with 6 x 50 mL portions of n-pentane Evaporation of the combined extracts in vacuo below 25° C. gave 24.0 g of the ester.

3.56 g of the ester dissolved in 50 ml of methanol was treated with 10 ml of 50% sodium hydroxide solution at 25°C. After 24 hours, the solvent was removed in vacuo at a temperature below 25°C, and the sodium salt of the product was extracted by washing the solid residue with hot water (5 x 100 mL). Cooling the extracts gave the crystalline sodium salt, which was converted by acidification (2N HCL) to give 4-azido-oc-bromo-O-chlorocinnamylideneacetic acid (Formula I). 4 g of the 4-azido-a-bromo-^-chlorocinnamylideneacetic acid was heated with 10 ml of thionyl chloride for 4 hours at 70-75°C. 5 ml of thionyl chloride was removed in vacuo, and the acid chloride was isolated by stirring the mixture with petroleum ether (boiling point range 40-60°C) and filtering.

2.00 g (0.01 g equivalents) of "Epikote 1007" was dissolved in a mixture of 8 ml of methyl ethyl ketone and 8 ml of dioxane. 3.47 g (0.01M) of the acid chloride was added and the mixture stirred for 10 minutes.

1.0 ml of pyridine was then added and the mixture was heated

with 5^°C for 2 hours. After: filtration, the solution was added dropwise to ethanol, and the precipitate was filtered off and washed with more ethanol.

Yield: 2.23 g

The UV spectrum showed a maximum at 349 nm

Extinction at 349 nm 1°</>=270 (dioxane) .

(b) Production of a printing plate. 2.5 g of 4-azido-a-bromo-3-chlorocinnamylideneacetic acid epoxy resin ester were dissolved in a mixture of equivalent volumes of 2-methoxyethyl acetate and dioxane, whereby a 5% solution was obtained. The solution was diluted with toluene to 2.5% and there-

after using a centrifugal machine, the surface of an electro-grained and anodized aluminum plate was applied, whereby a coating weight of 0.5 g per square meter was obtained. The plate was dried and then exposed and developed in the same manner as described in Example 1 (b). The plate was rinsed with water and printing ink applied.

EXAMPLE 3

(a) Preparation of the epoxy resin ester of 4-azidobenzylidene-g-cyanoacetic acid.

4-aminobenzaldehyde (Organic Svntheses. Collected Volume IV,

page 31 1963) was diazotized, and then allowed to react with sodium azide to form 4-azdobenzaldehyde. 15 ml of 4-azidobenzaldehyde was added with shaking to a solution of 11 g of cyanoacetic acid in 78 ml of a 7.5% aqueous solution of sodium hydroxide at 25-30°C. After two hours, the yellow solid was filtered off, redispersed in 700 ml of water and acidified with hydrochloric acid. 4-azidobenzylidene-g<->cyanoacetic acid (formula IV)

was filtered off, washed with water, dried and recrystallized in ethanol.

The acid chloride was prepared according to the procedure described

in example 2.

2.00 g (0.01 g equivalents) of "Epikote 1007" was dissolved in 9 ml of methyl ethyl ketone, and 1.64 g (0.007 M) of the 4-azidobenzylidene-g<->cyanoacetic acid chloride was added. 1.0 ml of pyridine was added

dropwise and mixture heated at 50°C for two hours. The solution was filtered and added dropwise to ethanol. The precipitate was filtered off and washed with more ethanol.

Yield: 2.70 g

The UV spectrum showed a maximum at 345 nm

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Extinction at 345 nm Elc°m=42° (dioxane)-

(b) Production of a printing plate

2.5 g of epoxy resin 4-azidobenzylidene-cc-cyanoacetic acid ester was dissolved in 23 ml of 2-methoxyethyl acetate, and this volume was diluted to 100 ml with toluene. 0.125 of "Neozapon (RTM) Blue FLE" (BASF), a phthalocyanine blue dye was added

and the mixture stirred for 10 minutes. After filtration to remove any solid dye particles, the solution was centrifugally coated onto the surface of an electro-grained and anodized aluminum plate. The plate was dried and exposed for one minute in the same manner as described in Example 1 (b). The color change of the light-affected areas of the exposed plate was from blue to green, whereby the green color was the result of the combination of blue dye and the yellow-brown photolysis product of the acid resin. The plate was developed in the same manner as described

in example 1 (b), rinsed and applied bold printing ink.

The presence of dye in the coating facilitated development in that the unexposed areas of the plate could be easily seen, because a readily visible image was formed.

EXAMPLE 4

(a) Preparation of the epoxy resin ester of 4-azidobenzylidene-a-cyanoacetic acid.

2.00 g (0.009 g equivalents) of "Epikote 1009" was dissolved in

9 ml of methyl ethyl ketone, after which 0.58 g (0.0025 M) was added

of acid chloride of 4-azidobenzylidene-α-cyanoacetic acid (formula IV) and 1.0 ml of pyridine. The mixture was heated at 50°C for 2 hours, filtered and added dropwise to ethanol. The precipitated ester was collected and washed with more ethanol.

Yield: 2.31 g

UV showed a maximum at 345 nm

Extinction at 345 nm E^"% =133 (dioxane).

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(b) Fabrication of a printed circuit.

5 g of an epoxy resin ester product was dissolved in 45 ml of 2-methoxyethyl acetate, and the volume was adjusted to 100 ml with toluene. The solution was applied to the copper surface of a plastic sheet laminated with a copper foil, and the application was carried out by means of a centrifugal machine at 80 revolutions per minute.

The coating was then dried by heating to 100°C for 2 minutes.

The plate was exposed for 3 minutes in contact with a negative

of a printed circuit, developed by immersion in 2-methoxyethyl acetate, dried and etched by immersion in 40% ferric chloride solution until the copper was completely removed from the areas not covered with etch-coating agents. This resulted in a pressurized circuit.

EXAMPLE 5

(a) Preparation of the epoxy resin ester of 4-azidobenzylidene-g-bromoacetic acid.

4.41 g of 4-azidobenzaldehyde in 100 ml of methylene chloride was added to 12.84 g of triphenylcarbethoxybromomethylene phosphorane in 100 ml of methylene chloride, and the resulting solution was allowed to stand at room temperature for 60 hours. The solvent was removed in vacuo at room temperature, whereby a crystalline mixture of ester and triphenylphosphine oxide was obtained, from which the ester was extracted by repeated washings with n-pentane. Removal of the solvent in vacuo at room temperature and from the combined extracts resulted in 7.86 g of a pale yellow crystalline product. Melting point 59-61°C.

3 g of the ester, which was dissolved in methanol, was treated with

10 ml of 50% hydroxide solution at room temperature, and this solution was allowed to stand for 24 hours. The solvent was removed in vacuo at 25°C, the residue dissolved in water, and the product

(formula XI) was precipitated by addition of 2N hydrochloric acid.

The acid chloride was prepared according to the procedure described in example 2.

2.00 g (0.01 g equivalents) "Epikote 1007" was dissolved in 18 ml

dioxane, after which 2.51 g (0.01 M) of 4-azidobenzylidene-α-bromoacetic acid chloride and 1.0 ml of pyridine were added. The temperature was raised to 50°C, and this temperature was maintained for 4 hours. The pyridinium chloride was filtered off and the solution added dropwise to ethanol. The precipitated ester was collected and washed with ethanol.

Yield: 2.10 g.

The UV spectrum showed a maximum at 319 nm.

Extinction at 319 nm'E?% =198 (dioxane).

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(b) Production of a printing plate.

2.5 g of epoxy resin 4-azidobenzylidene-α-bromoacetic acid ester was dissolved in 23 ml of 2-methoxyethyl acetate, and the volume was adjusted to 100 ml with toluene. The solution was applied to the surface | to an electro-grained and anodized aluminum sheet using a centrifugal apparatus. The procedure according to example 2 (b) for the production of a printing plate was repeated except that 2 minutes of exposure was necessary.

EXAMPLE 6

(a) Preparation of epoxy resin ester of 4-azido-2-chlorobenzylidene-α-cyanoacetic acid.

2-chloro-4-aminobenzaldehyde, which was prepared according to the indicated

. the method for 4-aminobenzaldehyde, was diazotized and allowed to react with

. sodium azide to form 4-azido-2-chlorobenzaldehyde, which is a

•yellow solid. 7.35 g of the 4-azido-2-chlorobenzaldehyde,

2.50 ml of glacial acetic acid and 2.86 g of cyanoacetic acid were stirred at 50°C

for 4 hours, after which 4-azido-2-chlorobenzylidene-oc-cyanoacetic acid (formula VII) was separated as a pale yellow solid. The product was filtered off, washed with glacial acetic acid and water, and recrystallized in methanol.

Yield 6.9 g.

The acid chloride was prepared according to the procedure described in example 2.

2.00 g (0.01 g equivalents) of "Epikote 1007" was dissolved in 9 ml of methyl ethyl ketone, after which 2.68 g (0.01 M) of 4-azido-2-chlorobenzylidene-α-cyanoacetic acid chloride and 1.0 ml of pyridine.

The temperature was raised to 50°C and held for 4 hours. After filtration, the solution was dropped into ethanol, and the precipitated resin was collected and washed with fresh ethanol.

Yield: 2.40 g.

The UV spectrum showed a maximum at 342 nm.

Extinction at 342 nm El. em =110 (dioxane).

(b) Production of a printing plate.

The procedure of Example 2 (b) was repeated except that the required exposure time was 2 minutes.

EXAMPLE 7

(a) Preparation of epoxy resin esters of 4-azido-3,5-dibromo-benzylidene-g-cyanoacetic acid.

10.30 g of 4-aminobenzaldehyde was dissolved in a solution of 2.75 g of HCl in 660 ml of water by heating the mixture until it boiled. 8.50 ml of bromine, which was dissolved in the minimal amount

water, was slowly added and the mixture stirred for 30 minutes. The 4-amino-3,5-dibromobenzaldehyde separated as a light brown precipitate.

Yield 7.01 g.

4-azido-3,5-dibromobenzaldehydes were prepared by diazotization of the amine followed by reaction between the product and sodium azide.

6.5 g of 4-azido-3,5-dibromobenzaldehyde was mixed with 6.0 ml of glacial acetic acid and 2.02 g of cyanoacetic acid, and heated for 4 hours at 50°C. On cooling and standing for 24 hours at room temperature, a crystalline mass of 4-azido-3,5-dibromo- j benzylidene-a-cyanoacetic acid (formula VIII) separated. The crystals were washed with a smaller amount of glacial acetic acid and then with a larger amount of water. The product was recrystallized from methanol.

Yield: 5.5 g.

The acid chloride was prepared according to the method described in example 2 (a).

2.00 g (0.01 g equivalents) of "Epikote 1007" was dissolved in 9 ml of methyl ethyl ketone, and then 3.38 g (0.01 M) of

4-azicb-3,5-dibromobenzylidene-α-cyanoacetic acid chloride and 1.0 ml of pyridine added in said order. The temperature was raised to 50°C and held there for 4 hours. After filtration, the resin was isolated by adding the solution dropwise to ethanol.

Yield: 3.39 g.

The UV spectrum showed a maximum at 334 nm

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Extinction at 334 nm E,/0 =340 (dioxane).

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(b) Production of a printing plate.

The procedure from example 1(b) is repeated except

that a plate of ball-grained aluminum was used as a substrate, and whereby an exposure time of 2 minutes was necessary. After developing and rinsing with water, the plate was supplied with

bold printing ink.

EXAMPLE 8 •

(a) Preparation of epoxy resin ester of 3-azidobenzylidene-α-cyanoacetic acid

3-Aminobenzaldehyde was diazotized, and the product was allowed to react with sodium acid to form 3-azidobenzaldehyde. This was condensed with cyanoacetic acid using the method described in example 3 (a), and the product (formula V3) was converted to acid chloride using the method described in example 2 (a).

2.00 g (0.01 g equivalents) "Epikote 1007" was dissolved in 9 ml

methyl ethyl ketone. 2.10 g (0.009 M) of 3-azidobenzylidine-α-cyano-acetic acid chloride was added and the mixture was stirred for 10 minutes.

1.0 ml of pyridine was added bg the temperature oct to 50°C and kept at this temperature for 2 hours. The resin was isolated by adding a filter solution to ethanol.

Yield: 3.14 g.

The UV spectrum showed a maximum at 300 nm.

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Extinction at 300 nm E '° =370 (dioxane).

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(b) Production of a printing plate.

2.5 g of epoxy resin 3-azidobenzylidene-α-cyanoacetic acid ester was dissolved in 23 ml of 2-methoxyethyl acetate. The exercise volume was

made up to 100 ml with toluene, and 0.25 g of 1,2-benzanthraquinone was added. After filtration to remove any undissolved super-serisibilizer particles, the solution was centrifuged on the surface of an electro-grained and anodized aluminum plate, giving a coating weight of 0.5 g/m o. The dried plate was exposed for one minute and developed on the same way as described in example 1 (b). The plate was rinsed and coated with oily printing ink.

EXAMPLE 9

(a) Preparation of epoxy resin ester of 3-azido-4-methylbenzylidine-g-cyanoacetic acid.

425 ml conc. sulfuric acid and 36 ml conc. nitric acid was mixed and cooled in an ice-acetone bath to 0°C. 100 ml of 4-tolu-

aldehyde was slowly added with stirring, whereby the reaction temperature of the mixture was kept between -2 and +2°C. The resulting mixture was heated to 40°C, after which it was allowed to cool to room temperature. The product was isolated by pouring a thin jet onto finely crushed ice. The yield of 3-nitro-4-tolualdehyde was 74 g. 50 g of respectively 3-nitro-4-tolualdehyde, dry cyanoacetic acid and glacial acetic acid were heated at 100°C for 7 hours. 3-nitro-4-methyl-benzylidene-g<->cyanoacetic acid was filtered and washed with glacial acetic acid and water.

Yield: 32 g.

25 g of 3-nitro-4-methylbenzylidine-g<->cyanoacetic acid were dissolved in 350 ml of alcohol. 350 ml of water was added and the mixture heated to boiling. 55 g of sodium ditronite were slowly added, and the mixture was allowed to stand under reflux for 30 minutes, cooled and acidified with hydrochloric acid. The solution was boiled until the smell of sulfur dioxide could no longer be detected. 50 ml conc.

hydrochloric acid was added and the mixture cooled to 0 to -5°C.

A 40% solution of sodium nitrite was added until a permanent smell of nitric acid was obtained. 20 g of sodium azide in 50 ml of water were added dropwise by means of a funnel, and the precipitated trazido-4-methylbenzylidine-g<->cyanoacetic acid (formula IX) was filtered by means of the pump. After washing with water, 5.78 g of the product was obtained.

The acid was converted to the acid chloride by using process

the manner described in Example 2 (a).

1.00 g (0.009 g equivalents) of "Epikote 1007" was dissolved in 6 ml of methyl ethyl ketone and added to a solution of 0.99 g (0.004 M) of the 3-azido-4-methylbenzylidene-ct-cyanoacetic acid chloride in 6 ml of methyl ethyl ketone. 0.5 ml of pyridine was added and the mixture heated at 75°C for 2 hours. After dilution with 8 ml of dioxane, the ester was isolated by dropping the solution into water.

Yield: 0.75 g.

The UV spectrum showed a maximum at 298 nm.

Extinction at 298 E^m=156 (dioxane)

(b) Production of a printing plate.

The procedure from Example 2 (b) was repeated with the only variation that the exposure time of 2 minutes was necessary to produce the desired image. The developed plate was rinsed with water and bold printing ink applied.

EXAMPLE . 10

(a) Preparation of the epoxy resin ester of 3-azido-4-methoxy-benzylidene-ct-cyanoacetic acid.

56.3 g of 4-anisaldehyde was added very slowly to a dry ice-cooled mixture of 18.3 ml conc. nitric acid and. 366. ml conc. sulfuric acid. After stirring for 1 hour, the mixture was poured into a large volume of ice water to which dry ice was occasionally added. 3-nitro-4-anisaldehyde was precipitated as a. pale yellow

fabric. The recrystallization in methylene alcohol gave a yield of 30.3 g.

10.5 g of 3-nitro-4-anisaldehyde, dry cyanoacetic acid and glacial acetic acid, respectively, were heated at 105°C for 6 hours and 120°C for a further 2 hours. After cooling and standing overnight, 6.0 g of 3-nitro-4-methoxybenzylidine-α-cyanoacetic acid was obtained. Reduction and conversion in 3-azido-4-methoxybenzylidine-oc-cyanoacetic acid (formula X) was obtained by using the method described in example 9 (a) for the preparation of 4-methyl substituted acid. The acid chloride was prepared according to the method described in example 2 (a).

IN

1.6 g (0.008 g equivalent) of "Epikote 1007" was dissolved in 15 ml of methyl ethyl ketone and added to 1.58 g (0.006 M) of 3-azido-4-methoxy-benzylidine-α-cyanoacetic acid chloride in 5 ml of methyl ethyl ketone. 1.0 ml of pyridine was added and the mixture was stirred at 75°C for 2 hours. After filtration, the solution was added dropwise to 400 ml

alcohol, and the precipitate was filtered off and washed with more alcohol.

Yield: 1.96 g.

The UV spectrum showed a maximum at 323 nm.

shelter

Extinction at 323 nm E1 ,/0 cm=228 (dioxane).

(b) Production of printing plate.

The procedure of Example 2 (b) was repeated except that the plate was exposed for 2 minutes and then developed with an emulsion consisting of 2 parts 10 Be° gum solution containing 1% phosphoric acid and 1 part 3-methoxybutyl acetate.

EXAMPLE 11

4- azido-oc-cyanocinnamylidin acetic acid (formula v). 4-azidocinnamaldehyde (manufactured according to U.S.

patent no. 3,598,844) was dissolved in 40 ml of dry pyridine and 2.8 g of cyanoacetic acid was added. 4 drops of piperidine were added and the solution was allowed to stand for 4 hours. The red colored solution was poured into ice water, which contained 30 ml conc. hydrochloric acid, and then 4 N HCl was added dropwise with stirring until a pH of 5 was obtained. The reddish-brown solid was filtered and dissolved in ether, after which it was dried over magnesium sulfate. 0.1 g of bone charcoal was added and the solution filtered. The filtrate was concentrated to give 1.3 g of a product which was recrystallized in ethyl acetate/petroleum ether.

Melting point: 174 * 5°C.

The UV spectrum showed a maximum at 355 nm.

Molar extinction coefficient at 355 nm:

34700 in methanol.

An epoxy resin ester of the acid was prepared in a similar manner to that previously described and used to produce a satisfactory printing plate.

EXAMPLE 12

4-azido-^-chlorocinnamylideneacetic acid (formula II).

20.7 g of 4-azido-P-chlorocinnamaldehyde was allowed to react with 34.5 g of triphenylcarbethoxymethylenephosphorane in methylene chloride as in example 2 (a). In this case, the ester was not isolated, and the residue remaining after removal of the solvent was dissolved in 40 ml of methanol and treated with 50 ml of 50% sodium hydroxide solution. After standing at room temperature for 18 hours, the methanol was removed in vacuo at a temperature below 30°C, and the sodium salt of the product was removed by extraction with 5 x 100 ml portions of hot water. Acidification of the cooled extracts with 2N hydrochloric acid gave 8.0 g of carboxylic acid. Recrystallization in methanol gave yellow microcrystals which decomposed at a temperature above 160°C.

The UV spectrum showed a maximum at 325 nm

Molar extinction coefficient at 325 nm = 37,150 in methanol.

An epoxy resin ester was prepared analogously to that previously

is described and used for the production of a satisfactory printing plate.

EXAMPLE 13

(a) Preparation of the 4-azidobenzylidene-α-cyanoacetate from a polyvinyl alcohol. A mixture of 7.3 g of "Moviol NSO-88" (RTM), which is a polyvinyl alcohol manufactured by Hoechst, and 79 ml of pyridine was heated to 90°C for one hour. An additional 79 mL of pyridine was added and the mixture was cooled to room temperature. 38 of the chloride of 4-azidobenzylidene-α-cyanoacetic acid (formula IV) was added in such a way that the temperature of the reaction mixture did not exceed 50°C. After stirring for 1.5 hours at this temperature, this mixture was diluted with 160 ml of dimethylformamide, and then added dropwise to 4 liters of water. The precipitate was collected on the filter, redispersed in 500 ml of ethanol and the mixture stirred for 30 minutes. After filtration, the solid was washed with water on the filter and then: dried at room temperature.

The UV spectrum showed a maximum at 345 nm.

(b) Production of a printing plate.

2.5 g of the above product was stirred with 100 dimethylformamide at 40°C for 3 hours. After filtration, the solution was applied to the surface of an electro-grained and anodized aluminum plate using a centrifugal machine at 80 revolutions per minute. The dried plate was exposed for 2 minutes in contact with a negative in a 4,000 watt pulsed xenon lamp and at a distance of 0.65 meters. The plate was developed with a mixture of 1100 ml of dimethylformamide, 250 g of "Texafor D.l" (RTM), 2-polyoxyethylene condensate of a glyceride oil and 10 ml of concentrated sulfuric acid to which 10% by volume of water was added.

EXAMPLE 14

(a) Preparation of epoxy resin benzoate 4-azidobenzylidene-g-j cyanoacetate. 6 g (0.03 g equivalents) of "Epikote 1007" was dissolved in 27 ml of methyl ethyl ketone. 4.9 g (0.021 g equivalents) of the acid chloride of 4-azidobenzylidene-α-cyanoacetic acid (Formula IV) was added and the mixture was stirred for 15 minutes. 1.2 ml of benzoyl chloride and 3.0 ml of pyridine were then added and the temperature raised to 50°C. This temperature was maintained for 2 hours. The mixture was then cooled and filtered, and the filtrate was added dropwise to ethanol. The precipitated ester was collected and washed with more ethanol.

Yield: 8.8 g.

The UV spectrum showed a maximum at 345 nm.

(b) Production of a printing plate.

The procedure from example 2 (b) was repeated with the only change that an exposure time of 1 minute was required.

EXAMPLE 15

Preparation of p-azidobenzalcyanoacetic acid.

Equivalent amounts by weight of azidobenzaldehyde and cyanoacetic acid

were condensed together using glacial acetic acid as a catalyst and using 55°C and a time of 4 hours. The reaction mixture was cooled and the yellow solid filtered off, washed with cold water and recrystallized in ethanol.

Preparation of p-azidobenzal cyanoacetyl chloride.

The acid prepared above was treated under reflux with

an excess of thionyl chloride for 4 hours. The acid chloride was isolated by precipitation from a light petroleum fraction.

Esterification with epoxy resin

An epoxy resin, known as "Epikote 1009", and which is derived

of epichlorohydrin and "Bisphenol A" and which has a molecular weight of

about. 3750 was dissolved in methyl ethyl ketone and an equivalent amount by weight of the acid chloride mentioned above was added. The mixture was heated on a water bath for 5 hours in the presence of a small amount of pyridine. The ester obtained was precipitated in industrial methylated spirit, washed with commercial methylated spirit

and dried to thereby form a pale yellow powder.

Production of a printing plate.

A 3% solution of the ester, which was prepared above, in a

mixture of 2-methoxyethyl acetate and toluene (1:3 volume) was applied by means of a centrifugal apparatus to the surface of a grained aluminum plate, which had been anodized in phosphoric acid electrolyte, and by which a coating weight of 0.5 g/square meters. After drying, the photosensitive plate was obtained

exposed to a negative and a Kodak No. 3 Step Wedge using a 2,000 watt pulsed xenon lamp. for one minute.

A deep yellow color was induced in the light-affected areas. The exposed plate was developed using a mixture of glycol ester and a wetting agent as described in British Patent No. 1,220,808.

The developed plate was "washed and inked. The image received light inking. The image corresponding to the Step Wedge was opaque at 9 and had a tail at 14.

Claims (4)

1. Light-sensitive polymer ester, characterized in that it consists of a polymeric polyhydroxy material which is esterified with an acid with the formula: where a and b are zero or 1, and a + b is at least 1; R is a phenyl group optionally substituted with one or more halogen atoms, alkyl groups or alkoxy groups^ and R^, R2, R3 and R^, which may have the same or different meanings, mean halogen atoms, hydrogen atoms, cyano groups, alkyl groups, aryl groups, alkoxy groups, aryloxy groups, aralkyl groups or aralkyl groups on the condition that at least one of the groups R^ to R^ means a halogen atom or a cyano group. 2. Light-sensitive polymer ester according to claim 1, characterized in that a and b both mean 1, R means a phenyl group, R^ means a chlorine atom, R2 and R^ means hydrogen atoms and R^ means a hydrogen atom, a bromine atom, a chlorine atom or a cyano group . 3. Light-sensitive polymer ester according to claim 1 or 2, characterized in that the polyhydroxy material is an epoxy resin. 4. Light-sensitive polymer ester according to claim 3, characterized in that the epoxy resin is the condensation product of a bisphenol and epichlorohydride.