CA1203106A - Method of forming images from liquid masses - Google Patents

Abstract

METHOD OF FORMING IMAGES FROM LIQUID MASSES

ABSTRACT

Images are prepared by a process in which a layer, supported on a substrate, of a liquid composition comprising (a) an anaerobically polymerisable material and (b) a photopolymerisable material is maintained in a substantially oxygen-free environment such that the composition solidifies. It is then exposed imagewise to actinic radiation and treated with a developer to remove parts of the layer which have not been struck by the radiation.
The anaerobically polymerisable and photopolymerisable materials may be a mixture of two or more materials having these different functions, such as an acrylate ester with an azido compound, or the two functions may be combined in a single molecule. The products are suitable for use in producing printing plates and printed circuits.

Description

~2~3~

Case 3-14039/ARL 325/+

~ETHOD OF FORMING I~GES FROM LIQUID ~ASS~S

THIS lNv~lLON relates to a method of forming images from liquid masses, particularly from liquid coatings on substrates, by exposing them to anaerobic conditions and then to actinic radiation.
Conventionally, production of an image by means of photopolymerisation is achieved by coating a support with a solution in a volatile organic solYent of a photopolymerisable substance, causing or allowing the solvent to evaporate so leaving a film of the photopolymerisable substance, irradiating the film with actinic radiation as through an image whereby the parts of the film struck by the irradiation become photopolymerised ~and less soluble) while those parts shielded from the irradiatiQn remain substantially unaffected, then dissolving away the unirradiated, unphotopolymerised parts of the film by means of a suitable solvent which does not dissolve the irradiated, photopolymerised parts.
This last stage is conventionally known as "deYelopment".
It would be desirable to have a process in which a layer of a photopolymerisable substance were applied to a support and this layer were converted into a substantially solid, non-tacky state, ready for irradiation, without the use of organic solvents. Not only would, in this stage, the use be avoided of solvents which might present problems of toxicity and flammability and also cause expense in their recovery, but production on a continuous basis of coated supports, ready for irradiation~would be facilitated.

We have found that this object can be achieved by the use, h~

in liquid form, of certain substances, or mi~tures of substances, capable of undergoing both anaerobic curing and photopolyn~erisation.
Removal of oxygen from a layer of s~ch su~stances can cause sl-lidification without affecting their abllîty to undergo photopolymerisation. ~hen desired, parts of the composition may be subjected to actinic irradiation, causing those parts to photocrosslink and thus become much more resistant to solution in solvents.

United States Patent Specification No, 4 291 118 describes a method for forming relief images from a film of a liquid photopolymerisable material, comprising solidifying the film by chemical hardening, then exposing or re~exposing the solidified film to actinic radiation in the form of a pattern so that parts of the film become chemically differentiated, and then selectively removing the portions of the fi]m not exposed to the patterned exposure to actinic radiation by washing with a solvent. The only method used for effecting solidification in aIl the embodiments described is exposure to actinic radiation, although the disclosure contains the remark "Heat could also by extension be used". The only photopolymerlsable materials mentioned are mi~tures of polyenes with polythiols. This method is not easy to carry out successfully, If the initial solidification is carried out by irradiation, great care must be taken to give the right amount of irradiation since, if too ~3~ii little is given? the liquid comp~sition will not solidify and if too much is given it will not be possible to obtain a good image after the second irradiation, Furthermore, the reaction between the polyene and tfie polythiol, which is initiated on exposure to actinic radiation, continues when such exposure is interrupted. It follows that if i~ages of good quality are to be obtained the i~agewise exposure stage ~ust be performed without delay. This is a further constraint on industrial utilisation of the process.

Although anaerobic solidification has been known for over 25 years, use of anaerobically polymerisable materials, alternatively referred to herein as anaerobically curable materials, has been restricted to adhesive bonding and sealing.

Compositions which are both anaerobically polymerisable and photopolymerisable are described in Japanese Patent Application Kokai 54-22445 (1979~ (Derwent CPI Abstract No, 24527B~ and Japanese Patent Application Kokai 55-112211 (1980) (Derwent CPI
Abstract No. 72533C~. When used in the bonding of nuts and bolts or other engaging parts, or in the sealing of cavities, the compositions are said to be applied to articles and cured both anaerobically and by the ac-;ion of light, irradiation with light being carried out before, during or after anaerobic curing.
It is indicated that when anaerobic curing is effected before irradiation, the only part of the composition which is not ~2(~3~

cured anaerohically is the surface, which is cured by the suhsequent irradiation to complete formation of the bond or seal.

This invention provides a process for t~e production of an image which c~mprises ~ 1~ maintaining in a substantially oxygen~free environment a layer, supported on a substrate, of a liquid con~osition containing ~ a~ an anaerobically polymerisable material and (b) a photopolymerisable material for a sufficient period for the said liquid composition to solidify, (2~ exposing imagewise to actinic radiation the said solidified layer, and (3) treating the layer with a developer to remove those parts of the layer which have not ~een exposed to the actinic radiation in (2).

The e~pression "exposing imagewise" includes both e~posure through an image-bearing transparency consisting of opaque and transparent parts and also subjecting to a laser beam moved in a predetermined pattern, for example as directed by a computer, so as to form an image.
The curable liquid compositions used in accordance with the present invention may comprise a mixture of one or more substances that are ar.aero~ically-curable with one or more 93~

- 5 ~

suhstances that are exclusively photopolymerisable, Alternatively, it may comprise one or more "dual~functional"` substances, that is substances which are both anaerohically~-curable and photopolymerisable, especially su~ostances having in the same molecule one or more groups which are anaerobically curable and one or more groups which are exclusively photopolymerisable; in this embodiment materials (a) and (b~ are the same. In a further alternative, the liquid composition may comprise a mixture of one or more such dual~
~unctional substanes ~ith one or more anaerobically~curable substances and/or one or more exclusively photopolymerisable substances.

Anaerobically polymerisable materials are well known and many are commercially available. The anaerobically polymerisable materials used in accordance with this invention generally comprise (i) an ester of an acrylic acid, optionally containing free acidic or amino groups, ~ ii) a polymerisation initiator for (i~ and, if desired, (iii) an accelerator for the polymerisation of ~i).
Suitable esters of acrylic acids (i~ include esters, especially acryla~es and methacrylates, of monohydric alcohols, of polyhydric alcohols (~ull and partial esters~, hydroxy-carboxylic, hydroxysulphonic, and hydroxyphosphoric acids, and of hydroxyalkylamines and hydroxyalkylni~riles, and acrylic ester-urethanes and -ureides. Such esters are most co~nercially available and any that are not may be prepared by known ~2~ 6 esterification techniques, Suitable esters of acrylic acids include those of formula cH2=c-c-o--ccH2~ -Cc~-~, -fHOr- C~C-CH2 Rl R b R

a is an integer o~ 1 to 8, b is an integer of 1 to 20, c is ~ero or 1, 0 R denotes -H, ;CH3, ~C2H5, -CH20H or -CH20C-~;CH2, R denotes -H, -Cl, -CH3, or -C2H5, and R denotes -E, 0~, or OCC=CH2.

Preferred among such compounds are those of formula I where a is from 1 to 4, b is from 1 to 5, and R de~otes -H or -~H3.
Compo~mds of formula r where b is 2 or more are described in United States Patent No. 2 895 950.
Other suitable esters are of formula CH2 IC C O - (CH2)d ~ C ~ - R3 11 ~2~3~

where b, c, R~ and R have the meanings assigned above, d is ~ero or a positive integer, provided that c and d are not both zero, e is 1~ 2, 3, or 4, and R denotes an organic radical of valency e linked through a carbon atom or carbon atoms thereof to the indicated b oxygen atoms.
Preferred among such compounds are those where, in formula II, b, c, and d are each 1, R is -H or -CH3, and R is the hydrocarbon residue of an aliphatic alcohol containing from 1 to 6 carbon atoms, such as -CH3 or -CH2 ~CH2--CH2 CH2-.

Compounds of formula II are described in United Kingdom Patent Specification No. 1 228 479, Yet other suitable esters are those of formul~

CH2=c-c-o-cH2-clH cH2`o Cc~c III
~ R OH

where ~3~

c and e have the meanings previously assigned, X4 denotes -H or -CH3, and R denotes an organic radical of valency e, linked through a carbon atom thereof other than the carbon atom of a carbonyl group.
More particularly, when c is zero, R5 may denote the residue, containing from 1 to 18 carbon atoms, of an alcohol or phenol having e hydroxyl groups.
R may thus represent an aromatic, araliphatic, alkaromatic, cycloaliphatic, heterocyclic, or heterocycloaliphatic group, such as àn aromatic group containing only one benzene ring, optionally substituted by chlorine or by alkyl groups each of from 1 to 9 carbon atoms, or an aromatic group comprising a chain.of two to four benzene rings, optionally interrupted by ether oxygen atoms, aliphatic hydrocarbon groups of 1 to 4 carbon atoms, or sulphone groups, each benzene ring being optionally substituted by chlorine or by alkyl groups each of from 1 to 9 carbon atoms, or, preferably, a saturated or unsaturated, straight or branched-chain aliphatic group, which may contain ether oxygen linkages and which may be substituted by hydroxyl groups, especially a saturated or monoethylenically-unsaturated straight chain aliphatic hydrocarbon group of from 1 to 8 carbon atoms.

3~

Specific examples of such groups are the aromatic groups of the ~ormulae -C6HS and -C6H4CH3, in which e is 1, 6 4 3)2 6 4 ~ and C6H4CH2C6H4-, in which case e is 2 and -C6H4(CH2C6H3-)f - CH2C6H4- ~here f is 1 or 2, in which case e is 3 or 4, and the aliphatlc groups of formula -CH2CHCH2- or -CH2CH(CH2)3CH2-, in which case e is 3, of formula -(CH2)4-, CH CHCH - -CH CH20CH2CH2-~ or (CH25H2 )2 2 2 which case e is 2~or of the formula -(CH2)3CH3, -(CH2)40H, .
-CH2CH=CH2, or -CH2CH=CHCH20H, in which case e is 1.
When c is 1, R may represent the residue, containing from 1 to 60 carbon atoms, of an acid having e carboxyl groups, preferably a saturated or ethylenically-unsaturated, straight chain or branched aliphatic hydrocarbon group of from l to 20 carbon atoms, which may be substituted by chlorine atoms and which may be interrupted by ether oxygen atoms and/or by carbonyloxy (-C00-) groups, or a saturated or ethylenically-unsaturated cycloaliphatic or aliphatic-cycloaliphatic hydrocarbon group of at least 4 carbon atoms, which may be substituted by chlorine atoms, or an aromatic hydrocarbon group of from 6 to 12 carbon atoms, which may be substituted by chlorine atoms.

Further preferred are such compounds in wnich R5 represents a saturated or ethylenically-unsaturated straight chain or branched aliphatic hydrocarbon group of from 1 to 8 carbon atoms, 3~

optionally substituted by a hydroxyl group, or a saturated or ethylenically-unsaturated straight chain or branched aliphatic hydrocarbon group of from 4 to 50 carbon atoms and interru?ted in the chain by carbonyloxy groups, or a sa~urated or ethylenically-unsaturated monocyclic or bicyclic cycloaliphatic hydrocarbon group of 6 to 8 carbon atoms, or an ethylenically-unsaturated cycloaliphatic-aliphatic hydrocarbon group of from 10 to 51 carbon atoms, or a mononuclear aromatic hydrocarbon group of from 6 to 8 carbon atoms.
Specific examples of these residues of carboxylic acids are those of the formula -CH3, -CH2CH3~ -CH2CH(OH)CH3, -CH2Cl~ and -C6H5, in which case e is 1,and-CH2CH2-, -CH=CH-, and -C~H4-, in which case e is 2.
Compounds of the general formula III are described in United Kingdom Patent Specifications Nos. 939 201, 1;006 587, 1 235 769, and 1 241 851, and United States Patents Nos. 3 221 043, 3 549 583, 3 632 854S 3 642 739, 3 657 117, and 3 697 619.
Still other suitable esters are acrylate-urethanes and acrylate~ureides of formula O O
CH2=f-C-0-R -X-C-NH R7 I~
- Rl - g ~%~3~

where R has the meaning assigned above, R denotes a divalent aliphatic, cycloaliphatic7 aromatic, or araliphatic group, bound through a carbon atom or carbon atoms thereof to the indicated -O- atom and -X- atom or group, X denotes -O-, -NH~, or -NCalkyl~-, in which the alkyl radical has from 1 to 8 carbon atoms, g is an integer of at least 2 and at most 6, and R denotes a g-valent cycloaliphatic, aromatic? or araliphatic group bound through a carbon atom or carbon atoms thereof to the indicated NH groupsO
Preferably R denotes a divalent aliphatic group of 2 to 6 carbon atoms and R7 denotes one of the following;
a divalent aliphatic group of 2 to 10 carbon atoms, such as a group of formula t 2~6 ~ CH2C(Ca3)2CH2cH(cH3~cH2~2-7 or -cH2cH(cH3)cH2c(cH3)2(cH2)2;

a phenylene group, optionally substituted by a methyl group or a chlorine atom; a naphthylene group; a group of formula H C H ~ ~C6H4CH2C6a4-, or C6 4 ( 3 2 6 4 or a mononuclear alkylcycloalkylene or alkylcycloalkylalkylene group ~2C~3~q~

of from 6 to 10 carbon atoms, such as a methylcyclohex-2,4-ylene, methylcyclohe~-2,6~ylene, or 1,3,3-trimethylcyclohex-5~ylenemethyl group.

Compounds of the general formula IV are described in United States Patent No. 3 425 988.
Yet other suitable acrylates are those of formula O OH
CH =C-C-O-CH CHCH -N-R

2 ll Z 2 l R _ ~ _ (R )j V
O OH
CH =C-C-O-CH CHCH - N-R8 2 ll 22 _ - h R

~here each R has the meaning previously assigned, each R denotes -H or an alkyl radical of 1 to 6 carbon atoms, optionally substitut~d by a cyano or hydroxyl group or by a group of formula O OH
Il l CH2= IC-C-O- CH2CHCH2 each R9 i9 a divalent aliphatic, aromatic, heterocyclic or cycloaliphatic residue of 1 to 10 carbon atoms, linking through carbon atoms thereof the indicated nitrogen atoms, h is zero or an integer of from 1 to 3, and is not less than j, j is zero or 1, and is 1 ~hen h is 2 or 3.

~3~

Preferably R8 denotes an isopropyl group and preferably R9 denotes an ethylene, propYlene, or p-phenylene group.
A specific example of a compound of the general formula V is that of formula Vl - OH
CH2=cHcoocH2c~cH2 NCH~CH322 Compounds o~ the general formula ~ are described in United Kingdon Patent Specification No. l 339 017.
Typical polyfunctional acrylic esters useful as (i) are the acrylates and methacrylates of ethylene glycol, butane-1,4-diol, neopentyl glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, trimethylolpropane, pentaerythritol, 1~4-bisc2-hydLu~y 3~methacryloyloxypropoxy~-butane, poly(2-hydroxy-3-~methacryloyloxy~propyl~ethers of bisphenols and phenol formaldehyde novolaks, 2,4-bis~2-methacryloyloxyethoxycarbonamido~toluene, 2,6-bis(2-methacryloyloxy-ethoxycarbonamido)toluene.
Preferred esters (i2 are those haYing only one acrylic ester, especially acrylate or methacrylate, group per molecule. These include acrylate and methacrylate esters of saturated or unsaturated monohydric alcohols which may be aliphatic alcohols such as 2-methoxyethanol or allyl alcohol, cycloaliphatic alcohols such as cyclohexanol or dicyclopentenyl alcohol, heterocyclic aliphatic ~%~3~

alcohols such as fururyl alcohol or tetrahydrofurfuryl alcohol, or araliphatic alcohols such.as fienzyl alcohol, Also included are esters of formula Ilr where e is 1, for example, 2-hydroxy-3-methacryloylo~ypropoxybenzene and 2-hydroxy-3-acryloyloxypropoxy-benzene,and partial esters of polyhydric alcohols, which may be prepared by esterifying the alcohol or by reQcting a 1,2 alkylene oxide with acrylic or methacrylic acid, Eor example polyethylene glycol monomethacrylate having 5 to 20 ethylene oxide units, polypropylene glycol monomethacrylate having 5 or 6 propylene oxide units, 2-hydroxyethyl methacrylate and 2-hydroxypropyl acrylate.
Other suitable esters are esters of polyhydric alcohols in which one alcoholic hydroxyl group is substituted by an acryloyloxy or methacryloyloxy group and the remaining alcoholic hydroxyl group or groups are substituted by other acyloxy groups, which may, for instance, be metal-chelating groups, for example, acetoacetoxyethyl methacrylate. Further suitable esters are acrylates and methacrylates of hydroxycarboxylic acids such as glycolic acid or dimerised acrylic acid (3-hydroxypropionic acid~, hydroxysulphonic acids such as 2-hydroxyethanesulphonic acid, hydroxyphosphoric acids such as 2-hydroxyethyl dihydrogen phosphate, hydroxyalkylamines such as 2-(diethylamino~ethanol and hydroxyalkylnitriles such as 2-cyanoethanol and ester-urethanes such as 2-methacryloyloxy ethoxycarbonamidobenzene.
Polymerisation initiators or catalysts which may be used in accordance with the invention include hydroperoxides, peroxides, ~%~3~6 ~-hydroxysulphones, a~omatic ~-aminosulphones and mixtures of an organic amine o~ide and a HN= acidic compound such as a sulphonic or carboxylic acid hydrazide, sulphimide, disulphonyl imide or acyl cyanamide. ~ydroperoxides, peroxides and mixtures of an amine oxide and a sulphonic acid hydrazide are preferred polymerisation initiators. Organic hydroperoxides which may be used include those of formula R1000~, where R is a monovalent organic radical containing up to 18 carbon atoms, especially an alkyl, aryl, or aralkyl radical containing from 4 to 13 carbon atoms. Typical hydroperoxides are ethyl methyl ketone hydroperoxide, tert.butyl hydroperoxide, cumene hydroperoxide, and hydroperoxides formed by the 02ygenation of cetene or cyclohexene, tert.butyl hydroperoxide and cumene hydroperoxide being especially effective. ~ydrogen peroxide may also be employed.
A range of organic peroxides may be used, such as 2,5-dimethyl-2,5-di(tert.butylperoxy~hexane, di-tert.butyl peroxide, dihexylene glycol peroxide, tert.butyl cumyl peroxide, isobutyl methyl ketone peroxide, and also peresters such as tert.butyl peracetate, tert.butyl perbenzoate, and tert.butyl perphthalate, Preferred amine oxides, which can also be used as their salts, are oxides of aromatic tertiary amines such as N,N-dimethyl-p-toluidine and N,N-dimethyl-aniline. Preferred hydraæides are those of aromatic sulphonic acids such as benzenesulphonic acid and p-toluenesulphonic acid, Suitable accelerators ~ include aliphatic amines having at least two primary aliphatic amino groups and their ketimines, such as diethylenetriamine or triethylenetetramine and their ketimines with isobutyl methyl ketone; polyisocyanates~ such as toluene-2,4-di~isocyanate; aldimines, tertiary amines, such as N,N~dimethyl~
benzylamine and triet~ylamine, imides and sulphimides, such as o-benzoic sulphimide; dithiocarbamates; amides and thioamides such as formamide; thiazoles such as 2~mercaptobenzthiazole; ascorbic acid; organic phosphites, quaternary ammonium salts and bases;
salts of transition metals; thioureas; and polymercaptans, especially esters of mercaptan-carboxylic acids, such as glycerol tris(thioglycollate~, In a particularly preferred embodi~ent, the accelerator is a mixture of a sulphimide such as o-benzoic sulphimide and an aromatic tertiary amine such as W,N-dimethyl-p-toluidine.
The amount of polymerisation initiator cii~ may yary between 0.01% and 15% by weight of the ester ~i~, quantities of from 1% to 10% by weight generally being used. The amount of accelerator (iii) used is also preferably from 1 to 10% by weight of the ester (i?.
Exclusively photopolymerisable materials Cb~ which may be used in accordance with the present invention may be those in which polymerisation is effected by direct activation of photosensitive groups through radiation or those in which the radiation activates a suitable photoinitiator molecule which then activates polymerisable groups.
Materials having photosensitive groups are well known and include those having at least two, and preferably three or more, groups which are azido? coumarin, stilhene? maleimido, pyridinone, chalcone, propenone, pentadienone, or acrylic acid groups which are su~stituted in their 3- positior. by a group having ethylenic unsaturation or aromaticity in conjugation with the ethylenic double bond o the acrylic grollp, Materials in which photopolymerisation is effected by activation of a photoinitiator which then activates polymerisable groups include epoxide resins, phenolic resins, urea~formaldehyde resins, cyclic ethers, cyclic esters, cyclic sulphides, cyclic amines and organosilicon cyclics in combination with a radiation-sensitive aromatic 'onium salt, such as diazonium, sulphonium, iodonium, and sulphoxonium salts.
Examples of suitable azides are those containing at least two groups of formula VII
N3Ar-where Ar denotes a mononuclear or dinuclear divalent aromatic radical containing in all from 6 to at most 14 carbon atoms, especially a phenylene or naphthylene group.
Examples o~ suitable coumarins are those containing groups of the formula ~ Rll _ VIII

3~

where R 1 is an o~ygen atom, a carbonyloxy group (-COO-), a sulphonyl group, or a sulphonyloxy group.
Examples of those containing stilbene groups are those containing groups of the formula R12 ~ CH=CH ~ IX

where R12 is the residue, containing up to 8 carbon atoms in all, of a five or six-membered nitrogen-containing heterocyclic ring, fused to a benzene or naphthalene nucleus, and linked through a carbon atom of the said heterocyclic ring adjacent to a nitrogen hetero atom thereof to the indicated benzene nucleus, such as a benzimidazolyl, benzoxazolyl, benzotriazolyl, benzothiazolyl, or a naphthotriazolyl residue.
Examples of those con~ining maleimide units are those having groups of the formula C
ll N~ X

C

where each Rl3 is an alkyl group of 1 to 4 carbon atoms, a chlorine atom, or a phenyl group, and especially a methyl group.

Examples of those containing pyridinone units are those having groups of the formula 3~

Rk4~_ XI

where R is an aliphatic or cycloaliphatic radical of 1 to 8 carbon atoms and k is zero or an integer of l to 4.
Examples of compounds containing c.halcone, propenone, and pentadienone groups are those containing groups of formula Rk5 16 or ~ y ~ ~ Rl6 XIII

where each R is a halogen atom, or an alkyl, cycloalkyl, alkenyl~
cycloalkenyl, alkoxy, cycloalkoxy? alkenoxy, cycloalkenoxy, carbalkoxy, carbocycloalkoxy, carbalkenoxy, or carbocycloalkenoxy group, such organic groups containing 1 to 9 carbon atoms, or is a nitro group, or a carboxyl, sulphonic, or phosphoric acid group in the form of a salt, k has the meaning previously assigned, R represents a valency bond or a hydrogen atom?
Y represents a grouping of formula ~2~3~

CH=~ - ~C - I=CH - or _RC_C_CH ~ 120 XIV XV

or Rl9 o -CH=C - C ~ B_~CH- XVI

R and R are each indiYidually a hydrogen atom, an alkyl group, e.g., of 1 to 4 carbon atoms, or an aryl group~ preferably a mononuclear group such as a phenyl group, or R and R
conjointly denote a poly~ethylene chain of 2 to 4 methylene groups, R and R are each a hydrogen atom? an alkyl group,~e.g., of 1 to 4 carbon atoms, or an aryl group which is preferably a mononuclear group such as a phenyl group, m and n are each zero, 1, or 2, with the proviso that they are not both zero, and Z is an oxygen or sulphur atom, Suitable 3-substituted acrylates contain groups of the general formula R CH=CCRl)COO- XVII

where ~3~

R21 is an aliphatic or mononuclear aromatic, araliphatic, or hetero-c~clic group which, as already indicated, has ethylenic unsaturation or aromaticity in conjugation with the ethylenic double bond shown, such as phenyl, 2-furyl, 2- or 3-pyridyl, prop-2-enyl, or styryl group, and Rl has the r^~ning previously assigned.
Specific examples are disorbates of poly(oxyal~ylene) glycols, polyvinyl cinna~ate, and epoxide resin-cinnamic acid products.
Onium salts which, when combined with an epoxide resin or other cationically-polymerisable substances, give photopolymerisable mix-~ures, are described in United States Patent Specifications Nos.

4 058 400 and 4 058 401. Suitable sulphoxonium salts that may be used for the same purpose are dislosed in United States Patent Specification No. 4 299 938, and in United States ~atent Specifica~ions Nos.
4 339 567 and 4 383 025.
Suitable dual-functional materials which may be used in the process of the present invention contain one or more acrylic ester groups which will polymerise under the anaerobic conditions used to polyme-rise the anaerobically-curing materials, and also one or more groups as previously described, which will polymerise when irradiated or when activated by an irradiated lecule. Preferred materials are those cont~ining one or more acrylic ester groups and one or more groups of formula X, XII or XIII, or one or more epoxide groups. Dual-functio nal materials may be made by introducing one or more acrylic ester groupq into a compound which already contains one or more photopoly-merisable groups - 22 ~

and also one or more reactive groups such as car~o~ylic acid, phenolic or alcoholic hydroxy, epoxide, or imido groups, Examples of classes of compounds containing a photopolymerisable group and also a carboxylic acid group are azidoaromatic acids;
carboxyl-substituted stilbene derivatives such as stilbenebenzimidazoles, stilbenebenzoxazoles, stilbene~enzotriazoles, stilbenenaphthotriazoles, and stilbeneben~othiazoles; carboxyl-containing maleimides,,where the two ethylenic carbon atoms of the maleimide ring are substituted by alkyl groups of 1 to 4 carbon atoms, phenyl groups, or chlorine atoms; and also acrylic acids substituted in the 3-position by groups having ethylenic unsaturation or aromaticity in conjugation with the ethylenic bond in the 2,3-position.
Examples of classes.of compound containing a photopolymerisable group and also a phenolic hydroxyl group are hydroxy-substituted chalcones and hydroxyphenyl-substituted propenones and penta-dienones. Examples of classes of compounds containing a photopolymerisable group and also an alcoholic hydroxyl group are hydroxy-substituted maleimides and hydroxy-substituted pyridinones. Such hydroxyl grou~-containing compounds may be reacted directly with an acrylic acid or acylating derivative thereof or they may first be converted into their glycidyl ethers, and these ethers then reacted with an acrylic acid or hydroxy-substituted ester thereof.

~%~
~ 23 ~

Examples of classes of compounds containing a photopolymerisable group and an imido group are disubstituted maleimides, where the two ethylenic carbon atoms of the malei~ide ring are substituted as specified above.
Suitable azidoaromatic acids are 4-azidobenzoic acid and other compounds of formula N3-Ar-COOH XVIII

where Ar has the meaning previously assigned.
Suitable carboxyl-containing stilbene deri~ati~es are 4-(l~methylbenzimidazol-2-yl~stilbene-4'-carboxylic acid~ 4~(2H-naptho~l,2~d~ triazol-2-yl)-stilbene-4t~carboxylic acid~ and other compounds of the general formula Rl ~ CH=CH ~ XIX

- COO~

where Rl has the meaning pre~iously assigned.
Suitable carboxy].-containing maleimides are N-(carboxyphenyl) dimethylmaleimide and other compounds of the general formula C N- R22 _ COOH

R13 \ CO /

where each R 3 has the meaning preYiously assigned and R22 denotes the residue, containing up to 14 carbon atoms, of an aro~atic, aliphatic, or cycloaliphatic aminocarboxylic acid after removal of a primary amino group and a carboxylic acid group.
Suitable hydroxy-substituted chalcones and hydroxyphenyl-substituted propenones and pentadienones are 1-(4-hydroxyphenyl)-1-(4-hydroxyphenyl) -l-oxo -3-phenyl--3-oxo-3-phenylprop-1-ene, prop-2-ene, 1-(2-furyl)-3-oxo-3-(4-hydroxyphenyl) prop l-ene, and other compounds of the general formula Y ~ or ~ y XXI XXII

where each R , k, Y, and Z hav`e the mP~n;ngq previously asslgned.

Suitable hydroxy-substituted maleimides and hydroxy-substi~uted pyridinones are N-(2-hydroxyethyl)dimethyLmaleimide, 4,6-dimethyl-1 (2-hydroxyethyl)pyridin-2 one, and other compounds of the general formula.

R13 ~ CO

C ~-R23-o~ or ~ ~
/ CO 123~0H

XXIII

~2~3~

where each R , R ~ and k have the meaning previouslv assigned and R denotes the residue, of not more than 8 carbon atoms, of an aliphatic or cycloaliphatic aminoalcohol after removal of an amino group and an alcoholic hydroxyl group.
Suitable imides are dimethylmaleimide and other comnounds of the general formula R ~ C /

~ C / XXV

where each R has the meaning previously assigned.
Suitable 3-substituted acrylic acids are of formula R21CU=C(Rl)COOH ` XXVI

where R and R2 have the m~n;nE5 previously assigned.
The acrylic group or groups may be introduced into such compounds by known methods, for example by esterification using an acrylic acid or a reactive derivative of an acrylic acld, or an acryloyl group~containing alcohol such as hydroxyethyl methacrylate.
Further substances which, in the presence of a radiation-sensitive aromatic 'oniu~ salt, m~y ~e used as dual-functional materials are those containing ~oth an epoxide group and an - 26 ~

acrylic ester group, preferably those of formula ,0~ 1 CH2-~H-CH2'0COCCR ~=CH2 XXVII

C~H ~CH-CH2-R24-CH2CH-CH20CoC~R )=CH2 XXVIII.

and CH2-CH-CH20CO-R ~COOR OCOC(R )=CH2 XXIX

where R is as hereinbefore defined, R 24represents the residue of a polyglycidyl compound after the removal of two glycidyl groups, R25 represents the residue of a polycarboxylic acid after the removal of two carboxylic acid groups, and R26 represents an alkylene chain of from 1 to 6 carbon atoms.
Suitable such residues R 4 include aihydric phenol, especially bisphenol7 residues after remGval of the two phenolic hydrogen atoms, glycol residues after removal of the two alcoholic hydrogen atoms, and hydantoin residues after removal of the two amidic hydrogen atoms Suitable residues ~ are saturated or unsaturated aliphatic or aro~atic dicarboxylic acid residues and aromatic tri- or tetracarboxylic acid residues, after removal of two - 27 ~

carboxylic acid groups, such as succinic, malonic, maleic, phthalic, trimellitic and pyromellitic acid residues. Suitable alkylene groups R26 are ethylene, propylene, and butylene groups.

It will be apparent that these compounds fall within the definition of compounds already suggested above for use as anaerobically polymerisable materials. In the absence of a radiation~sensitive cationic catalyst such as an aromatic 'onium salt, the epoxide groups of such compounds are not photopolymerisable.

Suitable compounds o formula XXVII to XXIX may be made by introducing a group -OCOC(R ~=CH2 into a compound which already contains one or more 1,2-epoxide groups or, conversely, by introducing one or more 1,2-epoxide groups into a compound that already contains one or more groups of formula -OCOC(R )=CE2.

A convenient method of introducing a group -OCOC(R )=CH2 into a compound that already contains epoxide groups to produce, for example, a compound of formula XXVIII comprises reaction of an at least diepoxide with a stoichiometric deficit, based on the epoxide group content, of a compound containing both a group -OCOC(Rl)=CH2 and also a group, such as a carboxylic acid, phenolic or alcoholic hydroxyl, or imido group, capable of reaction with a 1,2-epoxide group so as to introduce at least one acrylic ester group into the molecule. Suita~le polyepoxides include polyglycidyl esters of polycarboxylic acids such as succinic acid, polyglycidyl 3~

ethers of polyhydric alco~ols such as 6utane~1,4-diol and polyhydric phenols sllch as 2,2~bis(4-hydroxyphenyl~propane and poly(N~glycidyl) compounds such as N,N'-diglycidylhydantoins. It will be understood that this method will not usually give rise to a 100% yield of material containing, on the same molecule, both a 1,2-epoxide group and an acrylic group. The other material in the product comprises a mixture of unchanged starting material containing the original number of epoxide groups, and material in which all epoxide groups have been replaced by acrylic ester groups. However, since such mixtures may be successfully used in the present process, the fact that the reaction product is a mixture is of no consequence.

A con~enient method of introducing one or more epoxide groups into a compound having at least one group ~OCOC(R 2=CH2 to produce, for example, a compound of formula X~VII, comprises using as the former a compound which has also at least one alcoholic hydroxyl 9 or a carboxyl, group, and treating it such that the group or ~roups is or are converted into 1,2-epoxide groups, using methods known in the art of epoxide resins for converting hydroxyl or carboxyl groups into glycidyl ether or ester groups. ~or e~ample, the compound is caused to react with epichlorohydrin in the presence of a hydrogen chloride acceptor (usually a strong base, e.g., NaOH) and preferably of a catalyst such as a quaternary ammonium compound, a tertiary amine, a ~2~93~
~ 29 -transition metal salt, a thioether, or a sulphonium salt. Usually an excess of epichlorohydrin over the theoretical quantity required is employed, the excess serving as solvent for the reaction, which is nor~ally carried out at a temperature of 30 to 120 C, preferably 40 to 65 C, and usually under reduced pressure in order to remove the water formed during the reaction.
A convenient method o~ making compounds such as those of formula XXIX comprises converting a hydroxy-substituted compound containing a group -aCOC(R )=CH2 into a partial ester by reaction with a polycarboxylic acid anhydride, The free carboxylic acid group(s) may then be glycidylated, following the method outlined above, or may be esterified by treatment with a compound containing two or more epoxide groups, usually at 60 to 120C
in the presence of a strong base and a catalyst such as a quaternary ammonium compound, or a transi~ion metal salt.
Typical compounds of formulae XXVII to XXIX are glycidyl acrylate, glycidyl methacrylate, 2-(4-glycidyloxyphenyl)-2-(4-(3-acryloyloxy-2-hydroxypropoxy)phenyl)propane, 2-(4-(glycidyloxy-phenyl~-2-(4-(2-hydroxy~3-methacryloyloxy~propoxy)phenyl)propane, 1-(2-methacryloyloxyethoxycarbonyl~-2,4~ and 2,5~bis(glycidyloxy-carbonyl)benzene, 1-(2-acryloylo~yethoxycarbonyl)-2,4- and 2,5-bis(glycidyloxycarbonyl~benzene, 2-acryloyloxyetho~y glycidyl succinate, 2-methacryloyloxyetho~y glycidyl succinate, l-glycidyl-3-(3-acryloyloxy-2-hydrogypropyl3-5,5-dimethylhydantoin, l-glycidyl-3~(2-hydroxy-3~uethacryloyloxypropyl)-5,5-dimethyl-hydantoin, l-glycidyloxy-4-(3-acryloyloxy-2-hydroxypropyloxy)-butane, and l-glycidyloxy-4-(2~hydroxy-3-~ethacryloyloxypropyloxy)-butane.

Photopolymerisation may be effected by radiation in the presence of a photosensitiser such as 5-nitroacenaphthene, 4-nitroaniline, 2,4,7~trinitro-9-fluorenone, 3~methyl-1,3-diaza-1,6-benzanthrone, bis~dialkylaminolbenzophenones, especially Michler's ketone, i.e., bisCp-dimethylamino~benzophenone, and 2-chlorothio~anthone.
Generally 0.1 to 20%, and preferably 0,5 to 15~,by weight of the photosensitiser is incorporated, based on the weight of photopolymerisable substance.
Compositions used in accordance with the present invention may also contain various additives, such as inhibitors to prevent premature polymerisation, diluents, and thickeners. Typicai inhibitors are quinones or hydroquinones, which may be em~loy~d in quanti~ies of 0.001 to o.lZ by weight of the anaerobically-curing component (a).
Incorporation into the composition of an acrylic acid has been found to give a product which is easily developed by treatment with aqueous alkali. The preferred addition rate for such acids is 0.5 to 5.0Z by,weight, calculated on the total weight of the c~mposition.

3~

The compositions are stable for prolonged periods in the presence of a sufficient quantity of oxygen but cure when oxygen is excluded. They are therefore best stored in containers that have an adequate airspace therein andlor are permeable to air.
In the photopolymerising step actinic radiation of wavelen~th 20~-600 nm is preferably used. Suitable sources of actinic radiation include carbon arcs, mercury ~apour arcs? fluorescent lamps with phosphors emitting ultra~iolet light, argon and xenon glow lamps, tungsten lamps, and photographic flood lamps~
Of these, mercury vapour arcs, particularly sun lamps, fluorescent sun lamps, and metal halide lamps are most suitable. The time required for the e~osure of the solidified layer will depend upon a variety of factors which include, for example, the individual photopolymerisable material used, the proportion of that material in the composition, the type of light source, and its distance from the composition. Suitable times may be readily determined by those familiar with photopolymerisation techniques.
The compositions of this invention may be applied as a liquid to a substrate such as steel, aluminium, copper, cadmium, zinc, paper, plastics, or wood. If desired, when the substrate is other than a transition metal, it may be 'activated' by treatment with a mixture of a condensation product of an aldehyde with a primary or secondary amine and a sulphur-containing free ..

-~ ~ 2~3~
__32 -radical accelerator, or by treatment with a compound containing an oxidisable transition metal, Details of such activation processes are given in United States Patent Specification No, 3 616 0~0.

- After the coating has been applied to the su6strate oxygen is removed, for example by evacuation or by replacement with an oxygen-free gas such as ~oist or dry nitrogen. After the coating has anaero~ically solidified it is irradiated. By exposing part or parts of the coating to irradiation through a mask, those sections which have not been cured may be washed away with a solvent such as cyclohexanone, 2-etho yethanol, toluene, acetone, and mixtures thereof and aqueous solvents such as dilute aqueous sodium carbonate or sodium hydro~ide. Thus, the compositions of this invention may be used in the production of printing plates and printing circuits. Methods of producing printing plates and printed circuits from photopolymerisable compositions are well known.
The following Examples illustrate the invention, All parts are bv weight.

Materials used in t~e E~amples are prepared as follows:
1-(p-(2-Hydroxy-3-methacryloyloxypropoxy)phenyl)-5-phenylpenta-1,4-dien-3-one l-Phenylbut-l-en-3 one ~58.4 g~, and p-hydroxybenzaldehyde (48.8 g~ are dissolved in ethanol (300 ml~ and cooled to a temperature below 15C, using ~n ice bath. A solution of sodium hydroxide C20 g~ in water C80 ml~ is added oYer 2 hours, the t~mperature o~ the mixture beîng kept below 15 C. This solution is then neutralised to p~ 7 wit~ dilute hydrochloric acid. An oily solid separates Otlt, and this is filtered ar.l washed with toluene to give 30.5 g of 1-{p~hydroxyphenyl)-5-phenylpenta-1,4-dien-3~one.
This product (25 g~ is added, over 30 minutes, to a mixture heated at 80C of glycidyl methacrylate (14,3 g~, tetramethyl-ammonium chloride (0.12 8~, and 2,6-di-tertiary butyl-4-methyl-phenol (`0.08 g). The mixture is heated for a further 4l hours at 80C, by which time the epoxide content has fal]en to 0.24 equiv./kg. The mixture is cooled to give the desired product (39 g) which sol;difies on standing.
Resin Solution I
1,5-Bis(4-glycidyloxyphenyl~penta-1,4-dien-3-one (100 parts) is mixed with 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane (38.2 parts~, 2,2-bis(4-hydroxyphenyl~propane (27~3 parts~, tetraethylammonium bromide ~0.05 part~, and 2-hydroxyethyl methacrylate (166 parts~. This mixture is heated at 100 C for 18~ hours, by which time its epQxide value is 0.44 equivalent/kg and its YiSCoSity at 25 C is 26 Pa s, This mixture is Resin Solution I.

~3~

Resin Solution II
A mixture of 1,5~bis(4-glycidyloxyphenyl~penta-1,4 dien-3~one aoo partS2, 2,6~di-tert.butyl~4 methylphenol (0.8 part~, and 2-hydroxyethyl metfiacrylate ~31 parts~ is heated to 100C and a mixture of 5,5-dimethyl~ydantoin C30,5 parts) and tetramethyl-ammonium chloride (0.4 part~ is added portionwise over 20 minutes.
The mixture is then stirred at 100C for a furt~er 15 hours, by which time the mixt~lre has an epoxide content of 0.50 equivalent/kg and a viscosity at 25C of 56.5 Pa s. This mi-xture is Resin Solution II.

Resin Solution III
1,5-Bis(4-glycidyloxyphenyl)penta-1,4-dien-3-one (100 parts) is mixed with 2~2-bis(3~5-dibromo-4-hydroxyphenyl2propane (38.2 parts), 2,2-bis(4-hydroxyphenyl)propane (27.3 parts~, tetraethyl-a~nonium bromide (0.05 part) and 2-methoxyethylacrylate. This mixture is heated to 100 C for 3q hours, by which time its epoxide content is 0.53 equivalent/kg and its viscosity is 3.4 Pa s. This mixture is Resin Solution III.

Resin Solution IV

1,5 Bis(~-hydroxyphenyl~penta-1,4-dien-3~one t58.5 parts), 1,3-diglycidyl-5-pentamethylene hydantoin ~51.6 parts~, 2 hydroxy-ethyl methacrylate (110.1 partS2, and tetramethylammonium bromide 0.3 part) are mixed. This mixture is heated for 9 hours at 100C, then a further amount of tetraethylammonium bromide (0.3 g2 is added and the heating is continued for a further 6 hours, by which time the epo~ide content is 0,14 equiyalent/kg, T~e epoxide content is reduced to a negligihle value by adding acrylic acid ~2.5 parts) at this stage and heating for a further 11 hours at 100 C. This mixture is Resin Solution IV.

Resin Solution V
Benzophenone tetracarboxylic acid dianhydride ~692 parts~
is mixed with 2-hydro~yethyl methacrylate ~117 parts~, tetramethyl-ammonium chloride (3.2 parts) and 2,6~di-t-butyl-p-cresol (2.2 parts). The mixture is heated for S hours at 80 C, by which time no anhydride remains. This mixture is Resin Solution V.

Resin Solution VI' Phenyl glycidyl ether (1000 parts, epoxide content 6.37 equivalents/kg~ is mixed with triphenylphosphine ('3 parts), and 2,6-di-tert.-butyl-4-methyl phenol (,2 parts2 and heated to 100 C.
Over a period of 1 hour methacrylic acid (,547.8 parts~ is added whilst maintai~ing the temperature at 100C, and the heating is continued for a further 6 hours. On cooling the epo~ide content of this product is 0.84 equivalent/kg and its viscosity at 25C
is 0.0425 Pa s. Polyvinyl cinnamate ~10 parts~ is dissolved in the product (10 parts~ to give Resin Solution VI.
Resin VII
A mixture of an epoxy novolak resin (100 parts~ having an epoxide content of 5.61 equiv. per kg. and ~eing a polyglycidyl 3~
- 36 ~

ether made rom a phenol-formaldehyde novolak of average molecular weight 420, 2,6-di~t~butyl-p~cresol (0,2 part2 and chromium III
tris octanoate (0.1 part~ ~s heated to 120 C and cinnamic acid C83 parts~ is~ added over a period o~ 1 hour. Heating is cont;nued for a further 3l bours at 120 C and the mi~ture is then allowed to cool. The product becomes solid at room temperature and has an epoxide content of 0~16 equiv~ per kg.

Resin VIII - 2-acryloylQxyethoxycarbonamidobenzene This is prepared by adding hydroxyethyl acrylate (60 parts~
dropwise with stirring to a mixture of phenylisocyanate (59 parts) and dibutyl tin dilaurate (0.2 part~ followed by heating at 10 C
until all of the isocyanate has reacted.
Resin I~
A mixture of an epoxy novolak resin (9,9 parts) having an epoxide content of 5.61 equiv. per kg and being a polyglycidyl ether made from a phenol-formal~ehyde novolak of average molecular weight 420, 2,~-bis(4-hydroxyphenyl~propane (2.3 parts~, 4-azido-benzoic acid ~4.8 parts~, 2,6-di-t-butyl-p~cresol (0.14 part), tetramethylammonium chloride (0.05 part~ and cyclohexanone (40 parts~
are heated with stirring at 120 C for 5 hours~by which time the epoxide content is reduced to a negligible value. The cyclohexanone is then removed by distillation under reduced pressure., ., 37 ~

EXAMP~E 1 A composition containing N-c2-acryloylQxyethyl~dimethylmaleimide (lO parts), l,l,l-trimethylolpropane trismethacrylate C2 parts2, cumene hydroperoxide C0.3 part~, N,N-dimethyl-p-toluidine Co,01 part), benzoic sulphimide C0.02 part~, and 2-chlorothioxanthone (0.2 part) is applied by spin-coating to a copper plate, le~ving a coating 18 ~m thick. The plate is placed in an airtight container whieh is purged with nitrogen for 30 minutes at room temperature, after which time the coating has solidified to a tack-free film.

The film is irradiated through a negative or 15 minutes using a 5000w metal halide lamp at a distance of 750 mm, Development in cyclohexanone gives a good image on the plate.

EXAMP~E 2 A c position is prepared containing l-Cp~C2~hydroxy-3 methacryloyloxypropoxy)phenyl~ S~phenylpenta~1,4~dien~3~one (10.0 parts~, trimethylolpropane trismethacrylate (3.0 parts~, cumene hydroperoxide (0.3 part), N,N~dimethyl-p-toluidine Co.01 part), benzoic sulphimide (0.02 part)~and benzil dimethyl ketal (0.2 part), the purpose oE the last being to catalyse photopolymerisation o any trismethacrylate which has not already polymerised anaerobically. This liquid composition is applied by spin-coating onto a copper-clad laminate sheet, leaving a ~3~
~ 38 -coating 22 ~m thick. The plate is placed in an airtight container and nitrogen is passed in until the oxygen content of the atmosphere in the container is below O.S~ by volume.

After 30 minutes at roo~ temperature the plate is removed; the liquid composition has solidified to a tack-free film.
The film is irradiated thrcugh a negative for 15 minutes using a 5000 w metal halide lamp at a distance of 750 mm. Development in toluene gi~es a good image on the plate.
EXAMP~E 3 A composition is prepared containing N-(2-acryloyloxyethyl)-dimethylmaleimide (9.0 parts), cumene hydroperoxide (0.3 part), methacry}ic acid (1.0 part~, N,N-dimethyl-p-toluidine (0.01 part), benzoic sulphimide C0.02 part), 2~chlorothioxanthone (O.Z part), and benzil dimethyl ketal ~0.2 part2~ This composition is coated onto a copper-clad laminate, maintained in a nitrogen ~tmosphere, and irradiated as described in Example 2. Development is effected in 2% aqueous sodium hydroxide solution, giving a good image.
EXA~LE 4 A composition is prepared containing N-(2~methacryloyloxy-ethyl)dimethylmaleimide C9.0 parts), tetrahydrofurfuryl methacrylate (1.0 part), cumene hydroperoxide (0.3 part), N,N-dimethyl-p-toluidine (0.01 part), benzoic sulphimide (0.02 part), 2-chlorothioxanthone (0.2 part)S and benzil dimethyl ketal .., ~2~3~

(0.2 part). This coating is applied to a copper-clad laminate as described in Example 2. The wet coating -is then covered with a silicone-coated release paper and a vacuum (67 mm Hg) is applied between the laminate and the release paper. After 30 minutes the vacuum -i.5 released and the releaso paper is removed. The coating is dry and tack-free. The coating is then irradiated through a negative as described in Example 2, and a good image is developed by treatment with toluene.

A composition is prepared containing N~C2~methacryloyloxy-ethyl)dimethylmaleimide (9.0 parts~, tetrahydrofurfuryl ~ethacrylate (1.0 part), methacrylic acid (1.0 part~, benzil dimethyl ketal (O.1 part), 2-chlorothioxanthone (0.1 part), cumene hydroperoxide (0.7 part)~and the ketimîne C2.0 parts2 formed from triethylene-tetramine (1 mol) and isobutyl methyl ketone (2 mol,2 This composition is coated onto a copper~clad laminate as described in Example 2 and placed in an airtight chamber, The air -is displaced by nitrogen at atmospheric pressure which has been moistened by passage through water warmed to 40.
On removal from the nitrogen atmosphere after 10 minutes the coating is dry and tack~free, It is irradiated through a negative for 10 minutes using a 5000 w metal halide lamp at a distance of 750 mm. A good image is developed on treatment with 2% aqueous sodium hydro~ide.

~ ~2~3~0~

A compos;tion is prepared containing Resin Solution I
(10.0 parts~, cumene hydroperQxide (0,3 part~, N,N-dimethyl-p-toluidine (-0.01 part), ~enzoic sulphimide (0.02 part~ and ~enzil dimethyl ketal ~0.2 part~. This composition is applied to a copper-clad laminate, leaving a coating 6 ~m thick, and the laminate is maintained in a nitrogen atmosphere for 5 minutes, by whic~ time the coating is tack-free. It is irradiated through a negative and under ~ vacuum for 10 seconds, using a 5000w metal halide lamp at a distance of 750 mm. Development in cyclohexanone gives a good image on the plate.

A composition is prepared containing Resin Solution II (10 parts), cumene hydroperoxide (0.3 part~, N,N-dimethyl-p-toluidine (0-.01 part), and benzil dimethyl ketal (0.2 part). This composition is applied to a copper-clad laminate, leaving a coating 8 ~m thick. The laminate is maintained in a nitrogen atmosphere for 10 minutes, ~y which time the coating is tack-free.
It is irradiated through a negative and under vacuum for 10 seconds, using a 5000w metal halide lamp at a distance of 750 mm. Development in cyclohexanone gives a good image on the plate.

A composition ~s prepared containing 2,2-bis~(2-hydroxy-3 methacryloyloxypropoxy)phenyl~propane (60 parts), ~3~

tripropyleneglycol diacrylate (2~ parts~, 2~hydroxyethyl methacrylate C20 parts~, cumene hydroperoxide (3 parts~, benzoic sulphimide ~0,2 part~, N,N~dimethyl~p~toluidine CO.l part~, and benzil dimethyl ketal ~2 parts~, This composition is applied to a copper-clad laminate using a draw ~ar technique, to give a coating of 25-28 ~m. The laminate is then maintained in a nitrogen atmosphere for 15 minutes, 5y ~hich time the coating is tack~free.
It is irradiated through a negative and under a vacuum for 60 seconds, using a 5000w metal halide lamp at a distance of 750 mm.
Development in acetone gives a good image on the plate.

EX~PLE 9 A composition is prepared containing Resin Solution III
(10 parts), cumene hydroperoxide (0.3 part~, N,N dimethyl-p-toluidine (0.02 part), and benzoic sulphimide (0,04 part~. This composition is applied to a copper-clad laminate, giving a coating 10-14 ~m thick, which is then maintained in a nitrog~n atmosphere for 20 minutes, giving a tack-free coating, It is irradiated through a negative under vacuum for 60 seconds, using a 5000w metal halide lamp at a distance of 750 mm. ~evelopment in butyl digol gives a good image.

A composition is prepared containing Resin Solution IV
(9 parts), Resin Solution V ~1 part~, cumene hydroperoxide (0.3 part), N,N-dimethyl-p-toluidine ~0.01 part~ and benzoic sulphimide -~ ~2~3~

(0.02 part2, T~is composition is applied to a copper-clad la~inate giving a coating 18~-20 pm thick and the laminate is placed in a nitrogen atmosp~ere for 15 minutes, by which time the coating is tack-free. It is irradlated through a negative and under a vacuum for 30 seconds, using a 5000~ metal halide lamp at a distance of 750 mm. Development in a 2~ aqueous sodium car~onate solution with brushing gives an image.

EXAMP~E 11 A composition is prepared containing Resin Solution I
(100 parts~, p-toluenesulphonic acid hydrazide (1 part~, ~enzoic sulphimide (l part~ and N,N-dimethyl~p-toluidine-N-oxide Cl part~.
This composition is coated ontQ~a precleaned copper-clad laminate and placed in an atmosphere of nitrogen at 45C for 5 minutes to give a tack-free coating 25 pm thick. The coating is irradiated through a negative for 60 seconds, using a 5000w metal halide lamp at a distance of 750 mm. A good image is produced upon development in benzyl alcohol.

Resin Solution VI (20 parts2 is mixed with cumene hydroperoxide (0.6 part~, benzoic sulphimide (0.04 part2 and N,N-dimethyl-p-toluidine (0.02 part) and applied to a copper-clad laminate leaving a coating 6 pm thick. The laminate is then placed in a nitrogen atmosphere for 15 minutes to produce a tack-free coating. It is irradiated through a negative and under vacuum for 5 minutes, using 3~

using a 5000w halide lamp at a distance of 750 ~m. Development in a mixture of toluene and acetone (9:1) gives a good image on the plate.

A mixture of an epoxide novolak resin having an epoxide content of 5.61 eq/kg and being a polyglycidyl ether made from a phenol-formal-dehyde novolak of molecular weight 420 (50 parts), the tetraglycidyl ether of 1,1,2,2-tetrakis-(p-hydroxyphenyl)ethane having an epoxide content of 5.20 eq/kg (50 parts), 1,4-butane-diol dimethacrylate (60 parts), cumene hydroperoxide (7 parts) bis-(4-methyl phenyl)iodonium hexafluorophosphate ~2 parts), and Accelerator NL 53A~, a commercial product available from Akzo Chemie U.K. Ltd., Wandsworth, London S.W.
18. ~nd de~cribed as a solution of cobalt metal (10 %) in white spirit, (1 part) is applied as a coating 120-130lum thick onto a copper-clad laminate. The coated laminate is then placed in an air-tight chamber and the air displaced by nitrogen, which is preheated to a te~perature of 40~C, for a period of 5 minutes, after which the coating is dry and tack-free. It is then irr~ ted through a negative for 3 minutes using a 5000w metal halide lamp at a distance of 750 ~m. A good image i9 produced on development in acetone.

A mixture of Re~in VII (10 parts), N,N-diethylaminoethyl acrylate (5 parts)~ cumene hydroperoxide (0.6 part), benzoic , ~

~2~3~6 sulphimide (0,05 part~ and Michler~s ketone (0.2 part~ is applied to a copper~clad laminate as a coating 15~17 pm thick. The coated laminaté is placed in an air~tig~t cham6er and the air displaced by nitrogen, wfiich is preheated to 40 C, for 3 minutes, after which the coating is dry qnd tack~free, It is t~en irradiated through a negative for 3 minutes under a 5000w metal halide lamp at a distance of 750 mm. A good image is developed in ethanol.

E~A~PLE 15 A mixture of Resin VII (6 parts~ Resin VIII` ~4 parts~, cumene hydroperoxide ~0.5 part?, 6enzoic sulphîmlde C0.05 part) and Michler's ketone (0.2 part~ is applied to a copper-clad laminate as a coating 8-10 ~m thick, The coated laminate is placed in an air-tight chamber and the air displaced 6y nitrogen, which is preheated to 40C, for 5 minutes to give a dry, tack-free coating.
It is then irradiated through a negative for 1 minute using a 5000w metal halide lamp at a distance of 750 mm. A good image is developed in ethanol:acetone (19:1).

A mixture of Resin IX (80 parts2~ 2-cyanoethyl acrylate ~20 parts~
cumene hydroperoxide (5 parts?, and iron naphthenate C6% solution in white spirit? (0.1 part? is applied as a coating 10-12 ~m thick to a copper-clad laminate. The coated laminate is then placed in an air-tight chamber and the air displaced 6y nitrogen, which is preheated to 40 C, for lO minutes, after which the coating is tack-free. It is then irradiated through a negative for 2 minutes using 3~

5000w metal ~alide la~p at a distance o~ 75~ mm. A good image is devel~ped in toluene,

Claims (20)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for the production of an image which comprises (1) maintaining in a substantially oxygen-free environment a layer, supported on a substrate, of a liquid composition containing (a) an anaerobically polymerisable material and (b) a photopolymerisable material for a sufficient period for the layer of liquid composition to solidify, (2) exposing imagewise to actinic radiation the solidified layer, and (3) treating the layer with a developer to remove those parts of the layer which have not been exposed to the actinic radiation in (2).

2. A process as claimed in claim 1, in which the anaerobically polymerisable material (a) comprises (i) an ester of an acrylic acid, optionally containing free acidic or amino groups, (ii) a polymerisation initiator for (i), and, optionally, (iii) an accelerator for the polymerisation of (i).

3. A process as claimed in claim 2, in which the ester (i) is selected from esters of mono- and polyhydric alcohols, esters of hydroxycarboxylic, hydroxysulfonic, and hydroxyphosphoric acids, esters of hydroxyalkylamines and hydroxyalkylnitriles, acrylic ester-urethanes and acrylic ester-ureides,

4. A process as claimed in claim 3, in which the ester has only one acrylic ester group per molecule.

5. A process as claimed in claim 4, in which the acrylic ester is selected from acrylates and methacrylates of ethylene glycol, 2-methoxyethanol, tetrahydrofurfuryl alcohol, N,N-diethylamino-ethanol and 2-cyanoethanol, 2-hydroxy-3-acryloyloxypropoxybenzene, 2-hydroxy-3-methacryloyloxypropoxybenzene, 2-acryloyloxyethoxy-carbonamidobenzene and 2-methacryloyloxyethoxycarbonamidobenzene.

6. A process as claimed in claim 2, in which the polymerisation initiator (ii) is an organic hydroperoxide of formula R10OOH, where R10 is a monovalent organic radical containing up to 18 carbon atoms, hydrogen peroxide, an organic peroxide, or a mixture of an organic amine oxide and a sulphonic acid hydrazide.

7. A process as claimed in any of claims 2, 3 and 6, in which the anaerobically polymerisable material (a) contains an accelerator (iii) which is an aliphatic amine having at least two primary aliphatic amino groups, a ketimine thereof, a polyisocyanate, an aldimine, a tertiary amine, an imide, a sulfimide, an amide, a thioamide, a thiazole, ascorbic acid, an organic phosphite, a quaternary ammonium salt, a quaternary ammonium base, a salt of a transition metal, a thiourea, or a polymercaptan.

8. A process as claimed in claim 1, in which the photopolymerisable material (b) is one in which polymerisation is effected by irradiation activating photosensitive groups directly.

9. A process as claimed in claim 8, in which the photopolymerisable material (b) has at least two groups which are azido, coumarin, stilbene, maleimido, pyridinone, chalcone, propenone, pentadienone, or acrylic ester groups which are substituted in their 3-position by a group having ethylenic unsaturation or aromaticity in conjugation with an ethylenic double bond of the acrylic group.

10. A process as claimed in claim 9, in which the photopolymerisable material (b) contains at least two groups of formula N3Ar- VII

where Ar denotes a mononuclear or dinuclear divalent aromatic radical containing from 6 to 14 carbon atoms.

11. A process as claimed in claim 9, in which the photopolymerisable material (b) contains at least two groups of formula X

where each R13 is an alkyl group of 1 to 4 carbon atoms, a chlorine atom, or a phenyl group.

12. A process as claimed in claim 9, in which the photopolymerisable material (b) contains at least two groups of formula or XII XIII

where each R15 is a halogen atom, or an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkoxy, cycloalkoxy, alkenoxy. cycloalkenoxy, carbalkoxy, carbocycloalkoxy, carbalkenoxy, or carbocyclo-alkenoxy group, such organic groups containing 1 to 9 carbon atoms, or is a nitro group, or a carboxyl, sulfonic, or phosphoric acid group in the form of a salt, k is zero or an integer of 1 to 4, R16 represents a valency bond or a hydrogen atom, Y represents a grouping of formula or XIV XV

or XVI

R17 and R18 are each individually a hydrogen atom, an alkyl group, or an aryl group, or R17 and R18 conjointly denote a polymethylene chain of 2 to 4 methylene groups, R19 and R20 are each a hydrogen atom, an alkyl group, or an aryl group, m and n are each zero, 1, or 2, with the proviso that they are not both zero, and Z is an oxygen or sulphur atom.

13. A process as claimed in claim 9, in which the photopolymerisable material (b) contains at least two groups of formula XVII
where R21 is an aliphatic or mononuclear aromatic, araliphatic, or heterocyclyl group which has ethylenic unsaturation or aromaticity in conjugation with the ethylenic double bond shown and R1 denotes -H, -Cl, -CH3, or C2H5.

14. A process as claimed in claim 1, in which the photopolymerisable material (b) is one in which irradiation activates a suitable photoinitiator molecule which then activates polymerisable groups.

15. A process as claimed in claim 14, in which the photopolymerisable material (b) comprises an epoxide resin, phenolic resin, urea-formaldehyde resin, cyclic ether, cyclic ester, cyclic sulphide, cyclic amine or organosilicon cyclic, in combination with a radiation-sensitive aromatic 'onium salt.

16. A process as claimed in claim 1, in which the liquid composition comprises a dual-functional substance having both anaerobically polymerisable and photopolymerisable groups which is present as both (a) and (b).

17. A process as claimed in claim 16, in which the liquid composition comprises a mixture of the dual functional substance with an anaerobically polymerisable substance, an exclusively photopolymerisable substance, or both an anaerobically polymerisable substance and an exclusively photopolymerisable substance.

18. A process as claimed in claim 16, in which the dual-functional substance contains one or more acrylic ester groups which polymerise under anaerobic conditions and also one or more photosensitive groups which are azido, coumarin, stilbene, maleimido, pyridinone, chalcone, propenone or pentadienone groups, or acrylic ester groups which are substituted in their 3-position by a group having ethylenic unsaturation or aromaticity in conjugation with an ethylenic double bond of the acrylic ester group.

19. A process as claimed in claim 16, in which the dual-functional substance contains one or more acrylic ester groups which polymerise under anaerobic conditions and one or more groups which polymerise when activated by an irradiated molecule.

20. A process as claimed in any of claims 1 to 3, in which the substantially oxygen-free environment is produced by evacuation or by replacement with moist or dry nitrogen.