CA1315592C - Method of forming images - Google Patents

Abstract

3-15871/15932/+/ARL 368 Method of Forming Images Abstract of Disclosure The invention provides a process for the production of an image which comprises (i) applying to a substrate a layer of a liquid composition com-prising (A) a cationically polymerisable residue (B) a radiation-activated polymerisation initiator for (A) (C) a radiation-curable residue that is different from (A) and optionally (D) a radiation activated initiator for the cure of (C), (ii) subjecting the composition to actinic radiation having a wavelength at which initiator (B) is activated but at which the residue (C) and/or initiator (D) is not substantially activated, followed by heating, if necessary, so that (A) is polymerised and the layer of liquid composition is solidified, but remains curable, (iii) subjecting the solidified layer in a pedetermined pattern to actinic radiation having a wavelength that is different from that of the radiation used in stage (ii) and at which the radiation-curable residue (C) and/or the initiator (D) is activated, such that in the exposed areas (C) is substantially cured, and (iv) removing areas of the solidified layer that have not been substantially cured.

Description

- l - 1 31~ ~ 92 3-15871/15932/~/ARL 368 Method of Forming Images This invention relates to a method for forming images from liquid coatings on substrates involving exposures to actinic radiation at different wavelengths.

Conventionally, production of an image by means of photopolymeri-sation is achieved by coating a support with a solution in a volatile organic solvent of a photopolymerisable substance, causing or allowing the solvent to evaporate 80 leaving a film of the photopolymeri~able substance, irradiating the film with actinic radiation as through an image whereby ths part~ of the film struck by the irradiatlon become photopolymerised (and less soluble) while those psrt~ shielded from the irradiation remain substantially unaffected, then dissolving away the unirradiated, unphotopoly-merised 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 "development".

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, resdy for irradiation through an image, without the use of organic solvents. Not only woùld, 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 imagewise irradia-tion, would be faciliatet.

.... ,, ~ ~ ` ~ .

- 2 - ~31~92 We have found that thi~ ob~ect can be achieved by the use of certain liquid compositions containing either two or more matsrials, or at least one dual functional material, or both, one of which i8 polymerisable by the application of actinic radiation at one ~wavelength, and the other i9 polymerisable by the applicatlon of actinlc radiation at a second, and different wavelength. Solidifi-cation i8 effected by exposure to actinic radiation at one wave-length to which the mixture is sensitive, giving a stable, solid, but still photosensitive layer. However, since the other radiation-sensitive material or function is only sensitive at a different wavelength, prolonged exposure to radiation of the first wavelength has a negligible effect on the solidlfled material. It may therefore be solidified using the first wavelength without requiring very careful control over treatment time~, and, following this, may be stored for prolonged periods, in the absence of radiation of the second wavelength. When desired, parts of the composition are exposed to the radiation of the second wavelength at which the composition is sensitive. Further polymerisation then occurs in the exposed areas, 80 that a difference in physical propertles ls caused between those areas receivlng the second exposure and those not receiving the second exposure. Contact wlth a suitable solvent or other means of development removes the area not exposed to the second wavelength and ~o a negative image 18 formed.

~nited S~ates 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, usually by exposure to actinic radiation, then re-exposing the solldified film to actinic radiation in the form of a pattern 80 that parts of the film become chemically differentiated, and then selectively removing the portions of the film not exposed to the patterned exposure to actinic radiatlon by washing wlth a solvent.

There is no mention of the possibility of uslng actinic radiation of two differeDt wavelengths for the two exposures. In the example given, both exposures are to radiation from the same statlonary 1315~92 pulse xenon source. The only photopolymerisable materials mentioned are mixtures of polyenes with polythiols. This method is not easy to carry out successfully. When the initial solidification is carried out by irradiation, great care must be taken to give the right amount of irradiation since, lf too little is given, the liquid composition wlll 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 the polythiol, which is initiated on exposure to actinic radiation, continues when such exposure is interrupted. For this reason the specification recommends commencing the second irradiatlon less than 30 minutes, snd preferably less than 10 minutes after the first irradiation, stating that, in many systems, a retention time between treatments of 30 minutes or longer would result in the inability to attain a proper differentiation in the chemical condition in the solidified mass. This time limitation is a further constraint on industrial utilisation of the process.

This invention therefore provides a process for the production of an image which comprise~
(i) applying to a substrate a layer of a liquid composition comprising (A) a cationically polymerisable residue, (B) a radiation-activated polymerisation initiator for (A) (C) a radiation-curable residue that is different from (A) and optionally (D) a radiation-activated initiator for the cure of (C), (ii~ sub~ecting the composition to actinic radiation having a wavelength at which the initiator (B) i8 activated but at which the residue (C) and/or the initiator (D) are not substantially sctivated such that (A) is polymerlsed and the layer of liquid composition i~
solidified, but remains photocurable, 131~592 (iii) ~ub~ectlng the solidified layer in a predetermined pattern to sctinic radiation having a wavelength thst is different from thst of the radiation used in stsge ~ii) snd st which the radiation-curable residue (C) snd/or the initistor (D) i8 sctivated, such that in the expossd areas (C) is substantially cured, and (iv) removing areas of the solidified layer that have not been substantially cured.

The expression "subjecting ......... in a predetermined pattern to actinic radiation" includes both exposure through an image-bearing transpsrency consisting of opaque and trsnsparent parts, and also subjection to a beam of actinic radistion moved in a predetermined pattern, for example ss directed by a computer so ag to form an imsge.

The cursble liqùid compositions used in sccordsnce with the present invention may comprise a mixture of one or more cationically polymerisable substances, together with one or more substances that sre polymerised by expos~re to actinic radistion only at a different wavelength from thst used to activste the polymerisation ini-tiator (B). Alternatively, it may comprise one or more "dusl-func-tional" substances, that 18 substances hsving in the same molecule two types of photopolymerlssble function, one of which is activated only by irrsdistlon st a wavelength that is different from thst at which the polymerisstion initiator (B) may be activsted. The compositions msy further compri3e a mixture of one or more dual functional substances, as described, together with one or more single functional substances.

In one method, the first irradiation i9 effected using rsdistion in the visible spectrum, and the second irrsdistion is effected using ultrsviolet radiation; however both irrsdiations may be made using ultraviolet radiation, but of different wavelengths, or both irradistions msy be made using rsdistion in the visible spectrum, but of different wavelengths.

131~92 Polymerisation initiator (B) must ab~orb radiation at a diffe}ent wavelength from either residue (C) and, if present, from initia-tor (D). Where residue (C) and initiator (D) absorb radiation at ~;horter wavelength than initlator (B), they preferably do not absorb radiation at a wavelength above 500 nm.

Residues that are cationically polymerisable suitable for use as part (A) of the liquid composition, are well known and may be, for example, a cationically polymeri~able heterocyclic compound ~uch as a cyclic ether, e.g. an oxetane or B tetrahydrofuran or a cyclic ester, e.g. a lactone or an episulphide, e.g. ethylene ~ulphide.
Preferably (A) is a l,2-epoxide, a vinyl ether or a mixture thereof.
Suitable l,2-epoxides include ethylene oxide, propylene oxide and epichlorohydrin. Preferred 1,2-epoxides are glycidyl ether~ of alcohols or phenols, particularly monohydric alcohol~ or phenols, e.g. n-butyl glycidyl ether, n-octyl glycidyl ether, phenyl glycidyl ether and cresyl glycidyl ether, cyclo-aliphatic epoxides, including monoepoxides such as alpha-pinene oxide and epoxide resins such as 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate and its 6,6'-dimethyl derlvative, and glycidyl esters, particularly of monocarboxyllc acids such as propionic, cyclohexane carboxylic and benzoic acids. Suitable vinyl ethers include cycllc vinyl ethers containing a dihydropyran residue and, preferably, vinyloxyalkyl ethers of phenols.

A wide range of polymerisation initiators for A may be used. For instance, the radiation activated polymerisation initiator for (A) may be at least one compound of the formula (I):

R~an an LLQ l~q (I) wherein L i8 a divslent to heptavalent metal or non metal, Q is a halogen atom or one of the groups Q may be a hydroxyl group, q is an integer from l to 3, m is an integer corresponding to the valency of L+q, a is l or 2 and n is an integer of 1 to 3 and R is an ion selected from:

, (i) Ar-I -Ar' wherein Ar and Ar' are substituted or unsubstituted aromatic radicals;
(ii) ]Y-Z-(CO)x~
wherein Y represents an arene or dienylium group; Z represents an atom of a d-block transition element chosen from titanlum, vanadium, chromium, manganese, iron, cobalt, nickel, copper, noibium, molyb-denum, ruthenium, rhodium, palladium, silver, tsntalum, tungsten, rhenium, osmium, iridium, platinum and gold; and x is a positive integer such that the atom Z has a closed shell electron configura-tion;
(iii) aromatic diazonium ions;
( iV ) 1 ( R1 ) ( R2 M) ] +an wherein a i8 1 or 2; n is an integer from 1 to 3; M is the cation of a monovalent to trivalent metal from groups IVb to VIIb, VIII or Ib of the Periodic Table; Rl is a ~-arene and R2 is a ~-arene or the anion of a ~-arene (v) aromatic sulphonium lons; and (vi) aromatlc sulphoxonlum lons.

When R is an iodonium salt, the initlator may have the formula (II) lA I A ' ~+ lLQ ~-(k-l) (II) wherein Ar is a monovalent aromatic radical; Ar' is a divalent aromatic radical; h i8 0 and i is 1 or h is 2 and i is 0; ; - k-l; 1 is the valence of L; and k is greater than 1 and i9 an integer having a value up to 8; and L, Q and m are as defiend above.

Radicals lncluded by Ar can be the same or dlfferent, aromatlc carboxycllc or heterocycllc radicals havlng from 6 to 20 carbon atoms, which can be substltuted with from 1 to 4 monovalent radicals ~elected from C(l 8)alkoxy, C(l 8)alkyl, nitro or chloro. Ar is more particularly, phenyl, chlorophenyl, nitrophenyl, methoxyphenyl or pyridyl. Radicals included by Ar' are dlvalent radicals such as _ 7 _ 1 31 ~ ~9 2 (CH2)V~ ~s-wherein the index v is preferably 1 or 2.

The iodonium salts are used in eombination with a dye sensitiser.

Dyes which can be used in combination with the above identified aryliodonium 6alts in the practice of the lnvention are cationic dyes, such as shown in Vol. 20, p.l94-7 of the Kirk-Othmer Ency-clopedia, 2nd Edition, 1969, John Wiley and Sons, New York. Some of the cationic dyes which can be used are, for example, Acridine orange; C.I. 46005 Acridine yellow; C.I. 46035 Phosphine ~ C.I. 46045 ~enzoflavin, C.I. 46065 Setoflavin T; C.I. 49005.
,.
In addition to the above, ba~c tyes can also be used. Some of the~e basic dyes are shown in ~ol. 7, p.532-4 Kirk-Othmer Encyclopedia, as cited abcve and include Hematoporphyrin 4,4'-bisdimethylaminoben~ophenone and 4,4'-bisdiethylaminoben7Ophenone.
When R i~ a cation of formula iii), the initiator may have the formula (III) [Y-Z-(CO)xl [LQm] (III) wherein Y, Z, x, L, Q and m are as defined above.

When Y denote~ an arene group i.e., i~ itself a 6-electron ligand, this may be a mononuclear or polynuclear group, including a con-densed ring group. Preferably it is a hydrocarbon group, optionally * Trade-Mark - r . , .

131~92 substituted by one or more alkoxy groups, and preferably it contains from 6 to 18 carbon atoms, such as benzene, toluene, mesitylene, naphthalene, biphenyl, phenanthrene, fluorene, and anthracene.

When Y denotes a dienylium group it i8 preferably a cyclic group of one of the following formulae t\ / \ / \

p ~ \ ~ / ¦ A ~ - / P \ / ~ /

_.
pt. ~ RPt. ~ i \ / ~;_./
where RA denote~ an alkyl group of 1 to 4 carbon atoms, an alkoxy group of 1 to 4 carbon atoms, or sn alkyl group interrupted by one or more oxycarbonyl groùps and containing up to 12 carbon atoms, and p i~ zero, 1, 2 or 3.
Z preferably represent~ chromium, cobalt, nickel, and particularly iron or manganese.

Individual salts of formula III, where Y denotes an arens group, which are particularly preferred lnclude the hexafluorophosphates of ~-toluenetricarbonylmanganese, ~-benzeDetricarbonylmanganese, ~-mesitylenetricarbonylmanganese, ~ methyl-5,6,7,8-tetrahydro-naphthalenetricarbonylmanganese, ~-hexylbenzenetricarbonylmanganese, ~-methoxybenzene tricarbonylmanganese, and ~-hexyloxybenzenetri-carbonylmangane~e.

These salts ~stisfy the requirement that the central atom (manga-nese) has a clo~ed electron shell configuration, i.e. 18 electrons in it~ valency shell, univalent mangane~e in the unipo~itive cation contributing 6 electron~, the arene group contributing 6 electrons, and the three carbonyl groups contributing 2 electron~ each.

~ . .

.

~31~92 Salts of formula III are in general known and can be prepared a~
described in EP-A 94,9l4.

Indivldusl salts of formula III, where Y denotes a cyclic dienylium group, whlch are psrticularly preferred lnclude trlcarbonyl(cyclo-hexa-1,3-dienyllum)iron tetrafluoroborate, trlcarbonyl~l-methyl-cyclohexa-2,4-dienylium)iron hexafluorophosphate, tricarbonyl(l-methyl-4-methoxycyclohexa-2,4-dlenylium)iron hexafluorophosphate, tricarbonyl(2~methoxybicyclo[4.4.0]deca-2,4-dienylium)iron hexa-fluorophosphate, tricarbonyl(l-(acetoxy-methyl)-2-(methoxycarbonyl-acetoxy)ethylcyclohexa-2,4-dienylium)-iron hexafluorophosphate, tricarbonyl(l-ethyl-4-isopropoxycyclohexa-2,4-dienylium)iron hexafluorophosphate, trlcarbonyl(l-(methoxycarbonyl)-4-methoxycyclo-hexa-2,4-dienylium)iron tetrafluoroborate, and (n-cyclohexadienyl)-tricarbonyl iron II hexafluoroarsenate.

The~e salts llkewise ~atisfy the requirement that the central atom (lron) has a closed electron shell configuration, the iron contri-butlng 7 electrons, the dienylium group contributing 5, and the carbonyl groups also contributing 2 each (i.e. 18 in all).

When R is an aromatic dia~onium ion, the aromatic group may be unsubstituted or substituted by one or more arylthio, aryloxy, dialkylamino, alkyl or alkoxy groups.

When R is a metallocenium ion, the initiator may have the for-~ula (IV) (Rl~R2M)a] an aq [LQ ] q (IV) wherein a is 1 or 2, each of n and q independently of the other 18 an integer from 1 to 3, M i~ the cation of a monovalent to trivalent metal from groups IVb to VIIb, VIII or Ib of the Periodic Table, L, Q and ~ are as defined above, Rl is a ~-arene and R~ is a n-arene or the anion of a ~-arene.

1315~92 Possible ~-arenes Rl and R2 are, in particular, aromatic groups of 6 to 24 carbon atoms or heteroaromatic groups of 3 to 30 carbon atoms, which groups may be unsubstituted or mono- or polysubstituted by ldenticsl or different monovalent radical3 such as halogen atoms, preferably chlorine or bromine atoms, or Cl-C8 alkyl, Cl-C8 alkoxy, cyano, Cl-Cg alkylthio, Cz-C6 monocarboxylic acld alkyl ester, phenyl, C2-Cs alkanoyl or benzoyl groups. These ~-arene groups may be mononuclear, condensed polynuclear or non-condensed polynuclear systems, in which last-mentioned systems the nuclei may be linked together direct or through bridge members such as -S-, -0- or -C-C-.

R2 as the anion of a ~-arene may be an anion of a ~-arene of the aforementioned kind, e.g. the indenyl anion, and, in particular, the cyclopentadienyl anion, which anions may also be unsubstituted or mono- or ppoly~ubstituted by identical or different monovalent radicals such as Cl-C8 alkyl, C2-C6 monocarboxylic acid alkyl ester, cyano, C2-Cs alkanoyl or benzoyl groups.

Alkyl, alkoxy, alkylthio, monocarboxylic acid alkyl ester and alkanoyl substituents may be straight chain or branched. Typlcal alkyl, alkoxy, alkylthlo, monocarboxylic acid alkyl ester or alkanoyl substltuents are: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, n-hexyloxy, n-octyloxy, methylthio, ethylthio, n-propylthio, isopropylthio, n-butylthio, n-pentylthio and n-hexylthio, carboxylic acid methyl ester and n-pentyl ester, acetyl, propionyl, butyryl, and valeroyl. Alkyl, alkoxy, alkylthio and monocarboxylic acid alkyl ester groups containing 1 to 4 and especially 1 or 2 carbon atoms in the alkyl moieties and alkanoyl groups contalnlng 2 os 3 carbon atoms are preferred. Preferred substituted ~-arenes or anion~ of substltuted ~-arene~ are those contalning one or two of the above-mentioned substltuents, in particular chlorine or bromine atoms, methyl, ethyl, methoxy, ethoxy, cyano, carboxylic acid methyl or ethyl ester groups and acetyl groups.

11- 131~592 Rl and R2 may be identlcal or different ~-arenes. Suitable hetero-aromatlc ~-arenes are system~ containing S-, N- and/or O-atom~.
Heteroaromatic ~-arenes containing S- and/or O-atoms are preferred.
Examples of suitable ~-arene~ are: benzene, toluene, xylenes, ethylbenzene, cumene, methoxybenzene, ethoxybenzene, dimethoxy-benzene, p-chlorotoluene, chlorobenzene, bromobenzene, dlchloro-benzene, acetylbenzene, trimethylbenzene, trimethoxybenzene, naphthalene, 1,2-dihydronaphthalenes, methoxynaphthalenes, ethoxy-naphthalenes, chloronsphthalene~, bromonaphthalene~, biphenyl, stilbene, indene, fluorene, phenanthrene, anthracene, 9,10-dihydro-anthracene, triphenylene, pyrene, perylene, naphthacene, coronene, thiophene, chromene, xanthene, thioxanthene, benzothiophene, naphthothiophene, thianthrene, diphenylene oxide, diphenylene sulphide, acridine and carbazole.

If a is 2, then each R2 i~ preferably the anion of a ~-arene, and each M is an identical metal atom. Examples of anions of substituted ~-arenes are: the anions of methyl-, ethyl-, n-propyl- and n-butyl-cyclopentadiene, the anions of dimethylcyclopentadiene, of cyclo-pentadlene carboxylic acid methyl e~ter and ethyl ester, and of acetylcyclopentadiene, propionyl-cyclopentadiene, cyanocyclopenta-diene and benzoylcyclopentadiene. Preferred anions are the anion of unsub~tituted indenyl and especially an anion of unsubstituted cyclopentadiene.

The preferred value of a i9 1, Rl is benzene, toluene, xylene, cumene, methoxybenzene, chlorobenzene, p-chlorotoluene, naphthalene, methylnaphthalene, chloronaphthalene, methoxynaphthalene, biphenyl, indene, pyrene, perylene or diphenylene sulfide, and R2 i~ the anion of cyclopentadiene, acetyl-cyclopentadiene or indene, or benzene, toluene, xylene, trimethylbenzene, naphthalene or methylnaphthalene.

131~592 Ti+ T12~ Ti3~ Zr+ Zr2+, Zr3~, Hf , Hf , Hf , Nb , Nb , Nb , Cr , Mo , Mo , W , w2 , Mn , Mn , Re , Fe , Co Co3+, Ni2+ or Cu2+. Preferably, M i9 a chromium, cobalt, manganese, tungsten or molydenum cation, especially an iron cation, most preferably Fe Particularly preferred are complexes of formula IV, wherein a is 1, Rl i8 cumene, n6-pyrene or ~-naphthalene, and R2 is the anion of ~5-cyclopentadiene, _ is preferably 1 or 2, especially 1, and q is preferably 1.

The compounds of formula IV may be prepared by methods known per se, e.g. as descrlbed in EP-A 94,915.

Examples of suitable metals or non-metals L in the ion [LQ ] q in all the above compounds are Sb, Fe, Sn, Bi, Al, Ga, In, Ti, Zr, Sc, V, Cr, Mn and Cu; lanthanides such as Ce, Pr, and Nd, or actinides, such as Th, Pa, U or Np. Suitable non-metals are especially B, P
and As. Preferably L i~ P, As, B or Sb, with P and Sb being most preferred.

Examples of complex anions [LQml q are BF4 , PF6 , AsF6 , SbF6 , SbFs(OH) , FeCl4 , SnCl62 , SbCl6 , BiCl6 . The most preferred complex anions are SbF6 , BF4 , AsF6 and PF6 -In some cases when a compound of formula IV 18 used as polymeri-sation initiator, it msy be used in con~unction with an organic peroxide or hydroperoxide or a quinone, or heat may be applled after irradiation, lf lrradiation alone is in~ufficient to effect solidi-fication. Combinations of preferred compounds of formula IV and an oxidizing agent are described in EP-A 126,712.

131~92 A range of organic peroxides may be used such as 2,5-dimethyl-2,5-bis(benzoyl-psroxy) hexane, 2,5-dimethyl-2,5-bis(tert.butylperoxy) hexane, di-tert.butyl peroxide, dlhexylene glycol peroxide, tert.butyl cumylperoxide, isobutyl methyl ketone peroxide, and also per-acids and per-esters such ag perbenzoic acid, tert.butyl peracetate, tert.butyl perbenzoate and tert.butyl perphthalate.
Organic hydroperoxides which may be used include alkyl, aryl or aralkyl hydroperoxides having up to 18 carbon atoms. Typical hydroperoxides include methyl ethyl ketone hydroperoxide~ tert.butyl hydroperoxide, cumene hydroperoxide and hydroperoxides formed by the oxygenation of cetene or cyclohexene, tert.butyl hydroperoxide and cumene hydroperoxide being especially effective. Suitable quinones include benzoquinone.

Polymerisation initiators for (A) include onium salts. Onium salts which, when combined with an epoxide resin or other cationically-polymerlsable substances, give photopolymerisable mixtures, are described in United State~ Patent Specification~ No~. 4,05O,400 and 4,058,401. Suitable sulphoxonium salts that may be used for the same purpo~es are disclosed in United States Patent Specifications Nos. 4,299,938, 4,339,567 and 4,383,025. Iodonium salts that may also be used for this purpose are described in British Patent Specification No. 1,516,352. Iodosyl salts that may be used are described in European Patent Specification No. 0,104,143.

Materials having photosensitive groups which may be used as the curable residue (~) are well known and include those having at least two, and preferably three or more, groups which are azido, coumarin, stilbene, maleimido, pyridinone, chalcone, propenone, pentadienone, anthracene, or a,~-ethylenically unsaturated ester groups having aromaticity or ethylenlc unsaturation in conjugation with the ,~-un~atùration.

131~92 Another type of possible photocurable residue C) is cationically polymerisable material that is rendered photosensitive by addition of a suitable photoin~tiator D). Combinations of these types may be selected from the compound classes as described for A) and B).

The curable residue (C) may be an acrylic ester, in particular a compound containing at least two groups of formula CH2~CR3-Coo- (V) where R3 represents a hydrogen or chlorine atom, or a methyl or ethyl group.

Suitable esters having at least two groups of formula V include esters, e8pecially acrylates and methacrylates, of aliphat~c, cycloaliphatic, alicycloaliphatic, araliphatic or heterocycloali-phatic polyhydric alcohols, especially diols and triols, poly-hydroxy-, paricularly dihydroxy-, carboxylic acids; polyhydroxy-, particularly dihydroxy-, alkylamine8 and polyhydroxy-, particularly dihydroxy-, alkylnltriles. Acrylic ester-urethanes and -ureides may al8o be used. Such esters are, in general, commercially available, and any that are not may be prepared by known methods.

Suitable acrylic esters include those of formula CHz~C~ ~ ~ (CH2)z~(CHR4 ~ ,CHO ~ CHz (VI) where R3 i~3 as herebefore defined, Rs denotes H, -CH3, ~C2Hs, -CHzOH, or _CH2O-~
~ R3 : R4 denotes H, OH, or -0~ -CH2 - 15 ~ 1 31 5 ~92 Z i8 an integer of from l to 8~
b is an integer of from l to 20~ and c 19 zero or 1.

Among compounds of formula VI, tho~e where z is from l to 4, b is from l to 5 and R3 denotes a hydrogen atom or a methyl group are preferred. Specific example8 of 9uch compound9 are the diacrylate9 and dimethacrylates of ethylene glycol~ propylene glycol, butane-l,4-diol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, tetraethylene glycol and tetrapropylene glycol.

Other suitable acrylic ester9 are of formula:

[ CH2 R3 C ~ (CH2)d-(C~3R4) _o b ]e (VII) where b, c, R3 and R4 have the meaning9 a99igned above, d i9 zero or a po8itive integer, provided that c and d are not both zero, e is 2, 3 or 4, and R6 denotes an organic radical of valency e linked through a carbon atoms or carbon atom9 thereof to the indicated b oxygen atoma.

Preferred among compounds of formula VII are those where b, c, and d are each l, R3 i9 a hydrogen atom or methyl group and R6 is a hydrocarbon re9idue of an aliphatic polyhydric alcohol having from 2 to 6 carbon atom9, 8uch a9 a pentaerythrityl group. A specific example of 9uch compounds i9 pentaerythrityl tetrakl9 (dimethylene glycol acrylate).

Yet other suitable e9ters are those of formula:

[ CH2~ O-CH2~ H-CH2-O-(CO)C ~ R8 (VIII) where c and e have the meanings previously assigned, R7 denotes -H or -CH3, and R3 denotes an organic radlcal of valency e, linked through a carbon atom thereof other that the carbon atom of a carbonyl group.

More particularly, when c is zero, R3 may denote the residue, containing from 1 to 60 carbon atoms, of an alcohol or phenol having e hydroxyl groups.

R3 may thus represent an aromatic, araliphatic, alkaromatic, cyclosliphatlc, heterocyclic, or heterocycloaliphatic group, such as an aromatic group containing only one benzene ring, optionally substituted by chlorlne, bromine or an alkyl group 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, aliphatlc hydrocarbon groups of 1 to 4 carbon atoms, or sulphone groups, each benzene ring being optionally substituted by chlorine, bromine or an alkyl group of from 1 to 9 carbon atoms, or a satu-rated or unsaturated, straight or branched-chain aliphatic group, which may contain ether oxygen linkages and which may be substituted by hydroxyl groupB ~ especially a saturated or monoethylenically un~aturated straight chain aliphatic hydrocarbon group of from 1 to 8 carbon atoms.

Specific examples of such group~ are the aromatic groups of the formulae -C6H4C(CH3)2C6H4-, in which case e i8 2, and -C6H4(CHzC6H3)f-CH2C6H4- where f i8 1 or 2, in which case e iB 3 or 4, and the aliphatic groups of formula -CH2CHCH2- or CH2CH(CH2)3CH2-, in which case e is 3, or of formula -(CH2)4-, -CH2CH~CHCH2-, -CHzCH20CH2CH2-, or -(CH2CH2O)zCH2CH2-, in which case e is 2.

1315~92 When c is 1, Ra 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 1 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 ethylenlcally unsaturated cycloaliphatic or ali-phatic-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 or bromine atoms.

Further preferred compounds where c is 1 are those in which R8 represents a saturated or ethylenlcally unsaturated straight chain or branched aliphatic hydrocarbon group of from 1 to 8 carbon atoms, optionally substituted by a hydroxyl group, or a saturated or ethylenically unsaturated strai8ht chain or branched aliphatic hydrocarbon group of from 4 to 50 carbon atoms and lnterrupted in the chain by carbonyloxy groups, or a saturated 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 acid are those of formula -CH2CH2-, -CH~CH- and -C6H4- where e is 2.

Specific examples of suitable compound~ of formula VIII are 1,4-bls(2-hydroxy-3(acryloyloxy)propoxy)butane, poly(2-hydroxy-3-(acryloyloxy)propyl)ethers of bis(4-hydroxyphenyl~methane (bis-phenol F), 2,2-bis(4-hydroxyphenyl)propane (bisphenol A) and phenol-formaldehyde novolaks, bis(2-hydroxy-3-acryloyloxypropyl)-adipate and the methacryloyloxy analogues of these compounds.

131~92 Still other suitable esters are acrylate-urethanes and actrylate-ureides of formula:

[ CHz~C-C-o-R9-X-C-NH ~ R~ (IX) 3 g where R3 has the meaning assigned above, R9 denotes a divalent aliphatic, cycloaliphatic, aromatic or araliphatic group, bound through a carbon atom or carbon atoms thereof to the indicate -O- atom and -X- atom or group, X denote~ -O-, -NH- or -N(alkyl)-, in which the alkyl radical has from 1 to 8 carbon atoms, g i8 an integer of at least 2 and at most 6, and Rl denotes a g-valent cycloaliphatic, aromatic, or araliphatic group bound through a carbon atom or carbon atoms thereof to the indicate NH groups.

Preferably R9 denote~3 a divalent aliphatic group of 2 to 6 carbon atoms and Rl~ denotes one of the following:
a divalent aliphatic group of 2 to 10 carbon atoms, such as a group of formula -(CH2)6-, -CH2C(CH3)2CH2CH(CH3)(CH2)2-, or -CH2CH(CH3)CH2C(CH3)2~CH2)2--;or a phenylene group, optionally substituted by a methyl group or a chlorine atom; a naphthylene group; a group of formula -C6H4C6H4-, -C6H4CH2C6H4-, or -C6H4C(CH3)zC6H4-;
or a mononuclear alkylcycloalklylene or alkylcycloalkylalkylene group of from 6 to 10 carbon atoms, such as a methylcyclohex-2,4-ylene, methylcyclohex-2,6-ylene, or 1,3,3-trimethylcyclohex-5-ylene-methyl group.

Speclfic examples of compounds of formula IX are 2,4- and 2,6-(bis(2-aeryloyloxyethoxycarbonamido))toluene and the corres-ponding methacryloyloxy compounds.

' : , . .

131~592 Further suitable acrylic esters are those of formula 1~ 3 R1l-C - (CH200C ~ =CH2)2 (X) where R3 has the meaning assigned above, RlI denotes CH3-, C2Hs-, -~H20H or CH2-C(R3)COOCH2-, and R12 denotes -CH20H or -CH200C-C(R3)sCH2, especially 1,1,1-tri-methylolpropane triacrylate, pentaerythritol tetraacrylate and the corresponding methacrylates.

Still further suitable acrylic esters are those of formula 3 ~1 3 ~1 3 ~3 CHz~CCOOCHzCHOOC\ / COO HCH200C ~CH2 ~ 19 (XI) HOOC COOH

where R3 has the meaning assigned above, R13 denotes -H, -CH3 or -CH2Cl, and Ri9 denotes a tetravalent residue, containing up to 20 carbon atoms and one or more carbocyclic rings, of a tetracarboxylic acid after removal of four carboxyl groups, each indicate pair of groups -CooCH(Rl3)CH2oocc(R3)~cH2 and -COOH being directly linked to ad;acent carbon atoms.

Preferably, R3 and Rl3 are -H or -CH3 and R~9 i~3 the residue of an aromatic tetracarboxylic acid having one or two benzene ring~, e~peclally pyromellitic acid or benzophenone-3,3', 4,4'-tetra-carboxylic acid.

Any of the above acrylic esters may be used in combination and may be mixed with a diluent, particularly an acrylic ester hav~ng a low viscoslty such as an alkyl or hydroxyalkyl acrylate or ~ethacrylate.

131~92 Examples of suitable azides are those containing at least two groups of formula N3Ar--where Ar denotes a mononuclear or dinuclear divalent aromatic radlcal containing in all from 6 to at mo~t 14 carbon atoms, especially a phenylene or naphthylene group.

Examples of suitable coumarines are those containing groups of the formula i G I Rls _ (XII) 0~-\0/-\-~

where R1s is an oxygen atom, a carbonyloxy group (-C00-), a sul-phonyl group, or a sulphonyoxy group.

Examples of those containing stilbene groups are those containing groups of the fosmula R16__+_ ~ CH=CH--t~ ~ (XIII) '~,/- ~./-where Rl6 18 the residue, containing up to 8 carbon atoms in all, ofa 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 ad~acent to a nitrogen hetero atom thereof to the iDdicated benzene nucleus, such as a benzimi-dazolyl, benzoxazolyl, benzotriazolyl, benzothiazolyl, or a naphtho-t~iazolyl residue.

1315~92 Examples of those containing maleimide units are those having groups of the formula CO
\ / \
~ ~- (XIV) Rl 7 /"\

where each R17 i8 an alkyl group of 1 to 4 carbon atoms, a chlorine atom, or a phenyl group, and especially a methyl group or one of the groups Rl7 can be hydrogen and the other one is as defined above.

Examples of those containing pyridinone units are those having groups of the formula ./-~.
Rr8 t ! ( xv y~O

where Rl8 ia an allphatic or cycloaliphatic radical of 1 to 8 carbon atoms and r iB zero or an integer of 1 to 4.

Examples of compounds contalning chalcone, propenone, and penta-dienone groups are tho~e containing groups of formula ~r ~r ~r *---R19 (XYI) (XVII) where each Rl9 is a halogen atom, or an alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkoxy, cycloalkoxy, alkenoxy, cycloalkenoxy, alkoxy-carbonyl, cycloalkoxycarbonyl, alkenoxycarbonyl or cycloalkenoxy-~, ............... . .

131~92 carbonyl group, such organic groups containing 1 to 9 carbon atoms, or i~ a nitro group, or a carboxyl, sulphonic, or phosphoric acid group in the form of a salt.
r has the meaning previously assigned, R20 reperesents a valency bond or a hydrogen atom, y1 represents a grouping of formula 2 1 22 CH5C-~_ ~S ~ ~ --RC~CH~ R2 4 (XVIII) (XIX) or ( ) \ - ~R

R2l and R22 are each individually a hydrogen atom, an alkyl group, e.g. of 1 to 4 carbon atoms, or an aryl group, preferably a mono-nuclear group such as a phenyl group, or R2l and R22 con~ointly denote a polymethylene chain of 2 to 4 methylene groups, R23 and R2 4 are each a hydrogen atom, an alkyl group, e.g. of 1 to 4 carbon atoms, or an aryl group which is prefereably a mononuclear group such as a phenyl group, s and t are each zero, 1, 2, with the proviso that they are not both zero, and Z' is an oxygen or sulphur atom.

Suitable anthracenes are those containing anthryl groups, such as 1~, 2- or 9-anthryl groups, which are unsubstituted or have one or two bromo, chloro, methyl or nitro substituents.

Suitable conjugated unsaturated esters include those containing sorbate or cinnamate groups, such as disorbates of polyoxyalXylene glycols, polyvinyl cinnamates and epoxy resin-cinnamic acid reaction products.

Other suitable residuef3 (C) are the cationically polymerisation residues listed above for residues (A).

13~592 The radiation activated initiator ~D) thst polymerises the resi-~due (C) when exposed to actinic radiation, may be sensitive to visible light or to ultraviolet radiation.

Such initiators are known and include benzoin ethers, acyloin ethers, halogenated alkyl or aryl derivatives, aromatic carbonyl derivatives, metallocenes, mixture~ of Group IVA organometallic compounds with photoreducible dyes, mlxtures of quinones with aliphatic amines having hydrogen attached to an aliphatic alpha carbon atom, aliphatic dicarbonyl compounds, optionally mixed with an amine, 3-ketocoumarins, acyl phosphine oxides, metal carbonyls, onium salts, as described above, and mixtures of photoreducible dyes with reducing agents. Preferred radiation activated catalysts (D) are campherquinone with a tertiary amine having a hydrogen atom attached to an aliphatic slpha carbon atoms, such as bis(4-dimethyl-amino)benzophenone and triethanolamine, biacetyl, dimanganese decacarbonyl, benzil dimethyl ketal, l-benzoylcyclohexanol, ,a-dimethyl-~-N-morpholino-4-methylthioacetophenone, isobutyl benzoin ether, 2,2,2-trichloro-4'-tert.butylacetophenone, diethoxyaceto-phenone, coumarins having a carbocyclic or heterocyclic aromatic ketone group in the 3-position, such as 3-benzoyl-7-methoxy coumarin or 3-(4-cyanobenzoyl)-5,7-dipropoxy coumarin, mixtures of photo-reducible dyes, typically methylene blue or rose bengal, with a stannane such as trlmethyl benzyl stannane, tributyl 4-methylbenzyl stannane or dibutyl dibenzyl stannane, mixtures of photoreducible dyes with an electron donor ~uch as sodium benzenesulphinate or benzenesulphinic scid, and a titanium metallocene such as bis(pi-methylcyclopentadienyl) bis(sigma hexyloxytetrafluorophenyl)ti-tanium (IV).

Preferred metallocenes that are u~ed in the compositions are the titanocenes of formula:

~R
~ i ~XXI) R2s \ R27 - 24 - 1 3 1 ~ ~ ~ 2 where each group R25 i8 independently selected from an optionally substi-tuted cyclopentadlenyl or lndenyl group or together they form an alkylldene group of 2 to 12 carbon atoms, a cycloalkylidene group havlng from 5 to 7 carbon atoms in the ring, a group -Sl(R28)2 - or - Sn(R28 )2 - ~ or an optlonally substltuted group of formula Xl_.
'! ~ '! '! ~ '!
~.>~ ,x./

Xl denotes a methylene, ethylene, or 1,3-propylene group, R26 denotes a 6-membered carbocycllc or 5- or 6-membered hetero-cycllc aromatic rlng, substltutes by a fluorine atom or a -CF3 group ln at least one of the two po~itlons ortho to the metal-carbon bond, the ring optionally belng further substituted, or R26 wlth R27 denotes a group _Ql_y2-Ql-, Ql denotes a 5-or 6-membered carbocyclic or heterocycllc aromatic rlng, in which each of the two bonds iB ortho to the Ql _y2 bond, and each position meta to the Ql_y2 bond is substltuted by fluorine or -CF3, the groups Ql optionally being further substituted, y2 denotes a methylene group, an alkylidene group having from 2 to 12 carbon atoms, a cycloalkylidene group having from 5 to 7 carbon atoms in the ring, a direct bond, a group -NR2 8 -, an oxygen or ~ulphur atom, or a group -SO2-, -CO-, -Si(R28)2- or -Sn(R28)2-, R27 denotes an alkynyl or phenylalkynyl group that may be substi-tuted, an azido or cyano group, or a group of formula -Si(R28)2- or -Sn~R28)2-, or it has the same meanding as the group R26, and R28 denotes an alkyl group of from 1 to 12 carbon atoms, a cyclo-alkyl group of from 5 to 12 carbon atoms, an aryl group of from 6 to 16 carbon atoms, or an aralkyl group of from 7 to 16 carbon atoms.

The R25 groups are preferably identical. Suitable substituents for R25 are: linear or branched alkyl, alkoxy and alkenyl of 18, preferably 12, most preferably up to 6, carbon atoms, e.g. methyl, ethyl, propyl, isopropyl, n-butyl, tert-butyl, pentyl, hexyl, octyl, 1315~92 decyl, dodecyl, tetradecyl, hexadecyl, octadecyl and corresponding alkenyl and alkoxy groups; cycloalkyl and cycloalkenyl containing preferably 5 to 8 ring carbon atoms, e.g. cyclopentyl, cyclohexyl, cycloheptyl, methylcyclopentyl and methylcyclohexyl; aryl of prefereably 6 to 16 carbon atoms and aralkyl or preferably 7 to 16 carbon atoms, e.g. phenyl, naphthyl, biphenyl, benzyl and phenylethyl; nitrilo, halo~en, preferably F, Cl and Br, and also amino, preferably tertiary amino which may contain linear or branched alkyl groups containing up to 12, preferably 1 to 6 carbon atoms, especially methyl, ethyl, phenyl and benzyl groups. These amino groups may be quaternized, especially with linear or branched alkyl halides containing preferably l to 12 carbon atoms, especially 1 to 6 carbon atoms, preferably methyl or ethyl halides; linear or branched aminoalkyl, preferably tertiary aminoalkyl which may also be quaternised, in particular with alkyl halides, and the alkylene group in the aminoalkyl can be linear or branched and contains preferably 1 to 12, most preferably l to 6, carbon atoms, and i8 most preferably ~-branched Cl-Cl2alkyl.

The radicals R2s may contain l to 3 substituents, but preferably contain one substituent. It is preferred that both sub6tituents R2s are cyclopentadienyl~ or methylcyclopentadienyl .

Alkylidene groups Xl and y2 preferably contain 2 to 6 carbon atoms.
Exemplary of alkylidene groups and cycloalkylidene groups Xl and y2 are ethylidene, 2,2-propylidene, butylidene, hexylidene, phenyl-methylene, diphenyl-methylene, cyclopentylidene and cyclohexylidene.
Xl is most preferably methylene. R2 8 as alkyl preferably contains 1 to 6 carbon atoms and is e.g. methyl, ethyl, propyl, butyl or hexyl; R2~ aæ cycloalkyl is preferably cyclopentyl or cyclohexyl;
and as aryl i8 preferably phenyl; and as aralkyl is preferably benzyl.

~2s is preferably subst1tuted in both ortho-positions by fluorine or by -CF 3 .

1315~92 R26 as carbocyclic aromatic and fluorine-substituted ring may be indene, indane, fluorene, naphthalene and preferably phenyl.
Examples are: 4,6-difluoroinden-5-yl, S,7-difluoroind-6-yl, 2,4-di-fluorofluoren-3-yl, 1,3-difluoronaphth-2-yl and, preferably, 2,6-difluorophen-1-yl.

R26 as heterocyclic aromatic 5-membered ring preferably contains one hetero-atom, as 6-membered ring, contains preferably 1 or 2 hetero-atoms. Examples of such rings substituted by two fluorine atoms are: 2,4-difluoropyrrol-3-yl, 2,4-difluorofur-3-yl, 2,4-di-fluorothiophen-3-yl, 2,4-difluoropyrid-3-yl, 3,5-difluoropyrid-4-yl and 4,6-difluoropyrimid-5-yl.

R26 and R27 together as a group of formula -Ql-Y2-Ql- may be e.g.:

.~ ~._y2_.~ ._y2_.~ ~.
Qs/ ~ / \QS Qs/ ~ / ~Qs N~ ~._y2~ N .~ ~._y2_.~ ~.
Q5 \ / \Q5 Q5/ ~ ~ ~Qs ilil y2 tl li aDd `,~ Y2_~i b' ~ ~ Q5/ ~ ~ ~Qs wherein E is -O-, -S- or -NH-. y2 is preferably methylene, ethyl-idene, 2,2-propylidene, a direct bond, or -O- and Q5 i9 a fluorine atom or a -CF3- group.

The radicals R2s and the groups Ql in groups -Q1-Y2-Ql- can be partly or completely substltuted by further groups. Suitable groups are: linear or branched alkyl or alkoxy, each preferably of l to 18, most preferably 1 to 6, carbon atoms, e.g. methyl,. ethyl, propyl, butyl, pentyl, hexyl, and the correRponding alkoxy groups, with methyl, methoxy ~nd hexyloxy being preferred , 1315~92 cycloalkyl containing preferably 5 or 6 ring carbon atom~, aryl of preferably 6 to 16 carbon atoms and aralkyl of preferably 7 to 16 carbon atoms, e.g. cyclopentyl, cyclohexyl, phenyl or benzyl;
hydroxyl, carboxyl, CN, halogen such as F, Cl or Br, and amino, preferably tertiary amino which may be quaternised with an alkyl halide such as methyl chloride, methyl bromide or methyl iodide, examples of amino groups being methylamino, ethylamino, dimethyl-amino, diethylamino, pyrrolidyl, piperidyl, piperaæyl, morpholyl, N-methylpiperaæyl;
alkoxycarbonyl containing preferably 1 to 18, most preferably 1 to 6, carbon atoms in the alkoxy moiety, aminocarbonyl containing one or two C1-CI2alkyl groups in the amlno group, or aminocarbonyl containing heterocyclic amines such as pyrrolidine, piperidine, piperazine, N-methylpiperazine, and morpholine;
aminoalkyl, especially tertiary aminoalkyl which preferably contains C1-C6alkyl groups and which may be quaternised with an alkyl halide, most preferably tertiary aminoalkyl which may be substituted by C1-C6alkyl, e.g. dimethylaminomethyl and trimethyl-ammoniummethyl lodide.

RZ7 as alkynyl is e.g. 2-butynyl and, preferably, propargyl.

Examples of substituents for R27 as phenylalkynyl are halogen such as F, Cl, Br, C1-C6alkyl and C~-C6alkoxy, carboxyl, OH and CN, R27 preferably has the meaning of R26.

In a preferred embodiment of the invention, R26 and R27 in for-mula XXI are unsubstituted or substituted 2,6-difluorophen-1-yl or R26 and R27 together form a radical of the formula:

~ ~._y2_.~

wherein y2 and QS have the above meaning and y2 is in particular a direct bond, -CH2- or -O-.

131~592 A preferred group of metallocenes of the formula XXI comprises those compounds wherein each R2s is ~-cyclopentadienyl or ~-cyclopenta-dienyl which is substituted by C1-C4alkyl, preferably methyl, and each of R26 and R27 i9 a radical of the formula:

QS\ /QZ
.-Q3 XXIa \ = /
Q5~ \Q4 wherein each Of Q2, Q3 and Q4 independently is a hydrogen atom, F, Cl, Br, a tertiary amino group, preferably morpholino group, or an alkoxy group, preferably a methoxy or hexyloxy group and QS is as defined above. The amino or alkoxy group is preferably attached in the para-position to the free bond. A preferred subgroup comprises those metallocenes of the formula XXI, wherein each R2s i8 ~-methyl-cyclopentadienyl or ~-cyclopentadienyl, and each of R26 and R27 is a radical of the formula XXIa wherein Q2 and Q4 are H, F, Cl or Br and Q3 is H, F or alkoxy. Preferably, each of Q2 and Q4 independently is a hydrogen or fluorine atom, and Q3 i8 fluorine, or hexyloxy.

Compounds of formula XXI, and their preparation, are described in EP-A 122,223 or in EP-A 186,626.

Preferred Group IVA organometallic compounds used as lnitiators D) are organostannanes of formuls XXII:

~--CHz-Sn ~ R29 XXII
.=. 29 wherein R29 denotes an alkyl group of from 1 to 4 carbon atoms, or an alkenyl or alkynyl group of from 2 to 4 carbon atoms, and 131~592 R30 denotes a hydrogen or halogen atom or an alkyl or alkoxy group of from 1 to 4 carbon atoms.

Preferred compounds of formula XXII are those where R29 denotes an alkyl group of 1 to 4 carbon atoms and R30 denotes a hydrogen atom or an alkyl group of 1 to 4 carbon atoms.

These organostannanes are prepared by Grlgnard coupling of a benzyl magnesium halide with a trialkylthln halide in an inert solvent, followed by filtration, aqueous washing and distillation of the product.

Preferred photoreducible dyes that are used with the~e organostan-nanes are methylene blue and rose bengal.

It will be 3een that residues (A) and residues (C~ may apparently be the same. In any one composition they will always be different from each other, as it is important that residues (A) and residues (C) are polymerised at different wavelengths. It does not matter whether re~idue (A) is polymerised at a longer or shorter wavelength than residue (C) provided that only re~ldue (A~ i3 polymerised during the flr~t exposure to radiation. The choice of residues (A) to (D) will be made to achieve this ob5ect.

For example, where solidification due to cationic polymerisation of residue (A) takes place at a shorter wavelength than the subsequent cross-linking of residue (C), one of the "onium" salts described would be suitable for initiator (B) together with a metallocene or other compound activated at long wavelengths as initiator (D). A
preferred combination i9 the use of an onium salt as iDitiator (B) together with a titanocene of formula XXI, or an organostannate of formula XXII plus a photoreducible dye, as initiator (D).

Also it will be noted that epoxy resins are given as possible compounds for both residues (A) and residue~ (C). It is possible to u3e an epoxy re3in as residue (A) and also an epoxy resin as .

1315~92 residue (C) provided that appropriate resins together with an appropriate initiator (B) and catalyst (D) are chosen so that one i9 polymerised at one wavelength and one at a different wavelength. One preferred combination is a cycloaliphatic epoxide as residue (A) a ferrocenium salt as initiator (B), preferably with the BF4 or PF~
anions; a glycidyl ether as residue (C); and an "onium" salt as catalyst (D). In this case, residue (A) will be polymerised by irradiation at one wavelength, and residue (C) by irradiation at a shorter wavelength.

If desired the cationically polymerisable residue (A) and the radiation curable residue ~C) may form part of the same molecule, i.e. a dual-functional material. Preferred dual functional materials are those containing an ester of an ethylenically unsaturated monocarboxylic acid, particularly an ester group of formula V, with an epoxide group. Such dual-functional materials include glycidyl acrylate, glycidyl me~hacrylate and materials prepared by reaction of an unsaturated monocarboxylic acid wlth a stoichiometric deflclt of a di- or polyepoxlde.

The weight ratio of cationically polymerisable residue (A) to radiation curable residue (C) is not critical, als long as effective amounts of both components are used. Where (A) and (C) are on separate molecules, the weight ratio (A):(C) i8 generally within the range 1:0.1-10, especially 1:1-5. The amount of polymerisation initiator (B) that is used is also not critical, as long as there is enough to initiate polymerisation of (A) after the first exposure to actinic radiation. Typical amounts of (B) are within the range 0.1-50 parts by weight of (B) per 100 parts of (A), especially 0.2 to 10 part~.

The amount of organic peroxide or hydropeoxide may vary from 0.01 %
to 15 % by weight of residue (A), amounts of from 0.1 % to 10 % by weight generally being used.

.

1315~92 The liquid compositions used in the present invention may also contain further additives known and conventionally employsd in the technology of photopolymerisable materials. Examples of such additives are pigments, dyes, fillers and reinforcing agents, glass fibres, carbon fibres and other fibres, flame retardants, anti-static agents levelling agents, antioxidants, light stabilisers and surfactants.

Suitable sources of actinic radiation include carbon arcs, mercury vapo~r arcs, fluorescent lamps with phosphors emitting ultraviolet light, argon and xenon glow lamps, tungsten lamps, and photographic flood lamps. It i8 important that the first irradiation is effected using radiation of a different wavelength from that used in the second irradiation. The use of filters, to screen out irradiation of the unwanted wavelengths, may be found to be advantageous since, in this way,a single, wide spsctrum source of irradiation may be used.
If ~uch a single source of radiation is used, the first exposure i8 effected with a filter allowing such wavelengths to reaching the composition that will activate only polymeristion initiator (B). In the second exposure, the whole unfiltered spectrum of radiation may be used, 80 that the wavelength which effects cure of residue (C) can reach the composition.

The first exposure need only be long enough to activate the poly-merisation initiator (B). Usually a few minutes iR sufficient. The actual time needed can be readily determined by simple experiment.
The activated initiator (B), optionally in the presence of an organic peroxide or hydroperoxide causes residue (A) to polymerise.
In some cases when using a compound of formula IV as initiator (B), some heating may also be needed to assist the polymerisation. The composition may be heated to polymerise residue (A) for example at 8 temperature of 80~C to 120C. There is no need to heat any longer than the time needed to polymerise residue (A), a few minutes being sufficient. The actual temperature and time needed can be readily detemined by simple experiment. Curing may also take place by exposing to infra red irradiation after the first exposure.

~31~2 The compositions as descrlbed may be applied as a liquid to a substrate such 8S steel, aluminium, copper, paper, silicon or plastics. After the coating has been applied, the first exposure takes place, and, depending on the speciflc system, a heating step is carried out. This treatment results in solidification of the composition. The coated substrate is then stable and may be stored for prolonged periods away from actinic irradiation of the wave-length that will effect cure of (C). When desired, the coated substrate is given an imagewise exposure to actinic radiation of a different wavelength from that used in the first exposure. Those parts of the coating that have not received the second exposure may then be removed, usually by wsshing in a suitable solvent such as cyclohexanone, 2-ethoxyethanol, gamma butyrolactone, toluene, acetone, and mixtures thereof, or, depending on the resins in the formulation, by treatment with aqueous solvents such as dilute aqueous sodium carbonate or sodium hydroxida. Dry development, such as plasma etching, may also be used. Thus the process of this invention may be used in the production of printing plate~ and printed circuits, using well known techniques.

The invention is illustrated by the following Examples. In the Examples the resins used are:

Resin 1: This denotes 4-bromophenylglycidyl ether.

Resin 2: This is prepared by the following method:
Bisphenol A diglycidyl ether (250 g) is heated to 120C and a mixture of acrylic acid (94.9 g), chromium III trisoctanoate (0.16 g; 5 % solution in ligroin) and 2,6-di-tert.butyl-4-methyl-phenol (0.5 g) is added dropwise with ~tirring. Heating i~ continued for 5 hours, by which time the epoxide content of the mixture is negligible. The product, Resin 2 is 2,2-bis(4-(3-acryloyloxy-2-hydroxypropoxy)phenyl) propane.

.. . .

33 131~92 Resin 3: This denotes trimethylolpropane trisacrylate.

Resin 4: This denotes alpha pinene oxide.

Resin 5: This denotes 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclo-hexane carboxylate.

Resin 6: This denotes an o-cre301 novolak polyglycidyl ether having a softening point of 99~C and an epoxide content of 4.2 equi-valents/kg.

Resin 7: This is prepared by the following method:
A 2,2-bis(4-hydroxyphenyl)propane based epoxy resin having an epoxide content of 1.6 equivalents/kg (100 g) and 2,6-di-tert.butyl-4-methylphenol (0.1 g) is heated until molten, stirred together and heated to 130C. A mixture of acrylic acid (10.7 g), chromlum III
trisoctanoate (0.1 g; 5 % solution in ligroin) and 2,6-di-tert.butyl-4-methylphenol (0.2 g) is added dropwise over 30 minutes with stirrirlg. Heating is continued for 2 hours, by which time the epoxide content of the mixture is negligible. This gives Resin 7.

Resin 8: This denotes phenylglycidyl ether.

Resin 9: This denotes pentaerlthyritol tetraacrylate.

Resin 10: This denotes dibromocresylglycidylether.

Resin 11: This is prepared by the following method:
1,5-bis(4-glycidyloxyphenyl)penta-1,4-dien-3-one (50 g), dodecanoic acid (25 g) and chromium III tri~ octanoàte (0.2 g, 5 % solution in ligroin) are heated at 120C until molten. Stirring is started and heating continued at 120C for 2 hours, by which time the epoxide content of the mixture is 1.65 mollkg 1 This is diluted with phenylglycidylether (75 g) to give Resin 11.

,. . .

1315~92 Resin 12: This is prepared according to the procedure described in J. Polym. Sci. - Polym. Chem. (1983) 21 1785.
4-Bromophenol (17.3 g, 0.1 mole), powdered sodium hydroxide (6 g, 0.15 mole) and dimethylsulphoxide (30 ml) are stirred together under a nitrogen blanket for 30 minutes at 25~C, followed by 2 hours at 70C. 2-Chloroethylvinylether (16 g, 0.15 mole) is added dropwise over 30 minutes, ensuring the temperature does not exceed 80C. When the addition is complete, it is stirred at 7QC for a further 4 hours. This is then cooled and added to water (100 ml). The precipate is collected hy vacuum filtration and dried under vacuum at 40C.

In the following Examples different radiation sources are used:
~) 500 W tungsten lamp: This source emits radiation above 450 nm.
Radiation of shorter wavelength is cut-off by a filter.

II) 5000 W metal halide lamp: This ~ource mainly emits radiation of 340-450 nm wavelength.

III) 80 W/cm medium pressure mercury are lamp: This source mainly emits radiation of 200-400 nm wavelength.

Example 1: A mixture of Resin 1 (4.5 parts), Resln 5 (0.5 parts), Resin 2 (5 parts), (pi5-2,4-cyclopentadien-1-yl)-[(1,2,3,4,5,6-pl)-(1-methyl-ethyl)-benzene]-iron II hexafluorophosphate (0.25 part), benzil-dimethylketal (0.15 part), cumene hydroperoxide (0.3 part) and acetone (0.5 part) is ~tirred until a solution is obtained.

The mixture i9 coated onto copper-clad laminate in a layer 36 micro-metres thick. The coated laminate is then irradiated using 8 500 W
tungsten-halogen lamp at a distance of 20 cm for 10 minutes. The solidified coating is then irradiated through a transparency using a 5000 ~ metal halid lamp at a distance of 75 cm for 2 minutes.
Development in a mixture of propylene carbonate (5 parts), butyl 131~592 digol (~ diethylenglycol monobutylether) (3 parts) and gamma butyrolactone (2 parts) produces a negative image of the trans-parancy.

Example 2: A mixture of Resin 5 (5 parts), Resln 3 (5 parts), (piS-2,4-cyclopentadien-1-yl) (pi-trans stilbene) iron II hexa-fluorophosphate (0.25 part), 1-hydroxycyclohexylphenyl ketone (0.15 part), cumene hydroperoxide (0.1 part) and acetone (0.5 part) i~ stirred until a solution is obtained.

The mixture i9 coated onto copper-clad laminate in a layer 36 micro-metres thick. The coated laminate is then irradiated using a S00 W
tungsten-halogen lamp at a distance of 20 cm for 10 minutes. The 301idified coating is then irradiated through a transparency using 8 5000 W metal halid lamp at a distance of 75 cm for 3 minutes.
Development in tetrahydrofuran produces a negative image of the transparency.

A mixture of Resin 2 (5 parts), Resln 4 (5 parts), (piS-2,4-cyclopentadlen-1-yl) 1(1,2,3,4,5,6-pi)-(1-methyl-ethyl)-benzene]-iron II hexafluorophosphate (0.2~ part), benzildimethyl-ketal (0.15 part), cumene hydroperoxide (0.15 part) and acetone (0.5 part) is stirred until a solution is obtained.

The mixture i9 coated onto copper-clad laminate in a layer 36 micro-metres thick. The coated laminate is then irradiated using a 500 W
tungsten-halogen lamp at a distance of 20 cm for 8 minutes. The solidified coating is then irradiated through a transparency using a 5000 W metal halide lamp at a distance of 75 cm for 5 ~inutes.
Development in tetrahydrofuran produces a negative image of the tansparency.

Example 4: A mixture of Resin 2 (6~5 parts), Resln 4 (3.5 parts), (pi5-2,4'-cyclopentadien-l-yl) 1(1,2,3,4,5~6-pi)-1-methyl-ethyl)-benzenel-iron II hexafluoroantlmonate (0.2 part), 2-methyl-1-(4-.

131~9~

methylthio)phenyl-2-morpholino-propan-1-one (0.2 part), methyldl-ethanolamine (0.05 part), cumene hydroperoxide ~0.25 part) and acetone (0.5 part) is stirred until a solution is obtained.

The mixture is coated onto copper-clad laminate in a layer 36 micro-metres thick. The coated laminate is then irradiated using a 500 W
tungsten-halogen lamp at a distance of 20 cm for 5 minutes. The solidified coating is then irradiated through a transparency using a 5000 W metal halide lamp at a distance of 75 cm for 5 minutes.
Development in tetrahydrofuran, with rubbing, produces a negative image of the transparency.

Example 5: A mixture of Resin 5 (3.5 parts) Resin 2 (6.5 parts), diphenyliodonlum hexafluoroarsenate (0.2 part), acridine orange (0.02 part), benzildimethylketal (0.2 part) and acetone (0.5 part) is stirred until a solution is obtained.

The mixture i8 coated onto copper-clad laminate ln a layer 36 mlcro-metres thick. The coated laminate is then irradiated using a 500 W
tungsten-halogen lamp at a distance of 20 cm for 3 minutes. The solidified coating i8 then irradiated through 8 tgransparency using a 5000 W metal halide lamp at a distance of 75 cm for 5 minutes.
Development in tetrahydrofuran, with rubbing, produces a negative image of the transparency.

Example 6: A mixture of RQsin 5 (1.25 parts) Resin 2 (7.5 parts), Resin 4 (1.25 parts), (pi-cyclohexadienyl)tricarbonyl iron II
hexafluoroarsenate (0.2 parts), benzil dimethyl ketal (0.2 part) and acedtone (0.5 part) is stirred until a solution i8 obtained.

The mixture i8 coated onto copper-clad laminate in a layer 36 micro-metres thick. The coated laminate is then irradiated using a 500 W
tungsten-halogen lamp at a distance of 20 cm for 20 minutes. The solidified coating is then irradiated through a transparency using a 131~592 5000 W metal halide lamp at a distance of 75 cm for 5 minutes.
]Development in tetrahydrofuran, with rubbing, produces a netgative image of the transparency.

Example 7: A mixture of Resin S (1.25 parts), Resin 2 (7.5 parts), Resin 4 (1.25 parts), 2,5-diethoxy-4-(p-tolylthio)benzene diazonium tetrafluoroborate (0.2 part), benzil dimethyl ketal (0.2 part), talc (1 part) and acetone (0.5 part) is stirred until homogeneous.

The mixture is coated onto copper-clad laminate in a layer 12 micro-metres thick. The coated laminate is then irradiated using a 500 W
tungsten-halogen lamp at a distance of 20 cm for 15 minutes. The solidified coating is then irradiated through a transparency using a 5000 W metal halide lamp at a distance of 75 cm for 5 minutes.
Development in acetone produces a negative image of the trans-parency.

Example 8: A mlxturs of Re~in 5 (6.5 parts), Resin 6 (5 parts), (plS-2,4-cyclopentadlen-1-yl) [(1,2,3,4,5,6-pi)-(1-methyl-ethyl)-benzenel-iron II hexafluorophosphate (0.35 part), triphenylsul-phonium hexafluoroantimonate (0.25 part~ and propylene carbonate (0.25 part) is stirred until a solution is obtained.

The mixture is coated onto a copper-clad laminate in a layer 24 micrometres thick. The coated layer i8 then irradiated using a S00 W tungsten-halogen lamp as described in Example 1 for 5 minute~.
The solidified coating i9 then irradiated through a transparency using a 5000 W metal halide lamp at a distance of 75 cm for 3 minu-tes. Development in toluene with gentle rubbing produces a negative image of the transparency.

Example 9: A mixture of Resin 1 (4 parts) Resin 2 (6 parts), p-chlorophenoxy-p-tolylphenoxysulphoxoDium hexafluorophosphate (0.2 part), bis(pi-methylcyclopentadienyl) bis(sigma hexaneoxytetra-fluorophenyl)titanium (IV) (0.1 part) and propylene carbonate (0.1 part) is stirred until a solution i8 obtained.

- 38 - 1 3 1 5 ~ 9 2 The mixture is coated onto a copper-clad laminate in a layer 24 micrometres thick. The coated layer is then irradiated using a 80 W/cm medium pressure mercury arc lamp at a distance of 20 cm for 20 seconds. The solidified coating is then irradiated through a transparency using a 5000 W metal halide lamp at a distance of 75 cm for 3 minutes. Development in a 2:1 vlv mixture of toluene:acetone with gentle rubbing produces a negative image of the transparency.

Example 10: A mixture of Resin 2 (5 parts), Resin 4 (5 parts), bis(pi-methylcyclopentadienyl) bis(sigma hexaneoxytetrafluoro-phenyl)titanium (IV) (0.1 part), triphenylsulphonium hexafluoro-antimonate (0.25 part) and propylene carbonate (0.25 part) i5 stirred until a solution is obtained.

The mixture is coated onto a copper-clad laminate in a layer 24 micrometre~ thick. The coated layer is then irradiated using a 80 Wlcm m~dium pressure mercury arc lamp at a distance of 20 cm for 60 seconds. The solidified coating is then irradlsted through a transparency using a 5000 w metal halide lamp at a distance of 75 cm for 3 minute~. Development in ethanol with gentle rubbing produces a negative image of the transparency.

Example 11: A mixture of Resin 1 (5 part~), Resin 7 (5 parts), (piS-2,4-cyclopentadien-1-yl) ~(1,2,3,4,5,6-pi)-(1-methyl-ethyl)-benzene~-iron II hexafluorophosphate (0.5 part), benzildimethylketal (0.5 part) and acetone ~1 part) is stirred until a solution is obtained.

The mixture is coated onto copper-clad laminate in a layer 12 micro-metres thick. The coated laminate is then irradiated using a 500 W
tungsten-halogen lamp with a filter to cut out irradiation below 450 nm at a distance of 20 cm for 10 minutes and heated at 90C for 5 minutes to give a tack-free film. The solidified coat~ng is then irradiated through a tgransparency using a 5000 W metal halide lamp .

131~2 producing radiaton within a wavelength region of 340-450 nm, at a di~tance of 75 cm for 2 minutes. Development in propylene carbonate produces a negative image of the transparency.

Example 12: A mixture of Resin 1 (2 parts), Resin 5 (4 parts), Resin 2 (4 parts), (piS-2,4-cyclopentadien-1-yl) [(1,2,3,4,5,6-pi)-(l-methylethyl)-benzene]-iron II hexafluorophosphate (0.6 part), benzildimethylketal (0.4 part) and acetone (0.5 part) are stirred until a solutlon is obtained.

The mixture is coated onto a copper-clad laminate in a layer 12 micrometres thick and the coating solidified by irradiation using a 500 W tungsten-halogen lamp at a distance of 20 cm for 3 minutes followed by heating at 90C for 3 minutes. The solidified coating is then irradiated through a transparency using a 5000 W metal halide lamp at a distance of 75 cm for 2 minutes. Development in 1,1,1-trichloroethane produces a negative image of the transparency.

Example 13: A mixture of Resin S (5 parts), Resin 2 (2.5 pàrts) Resin 3 (10 part~), (piS-2,4-cyclopentadien-1-yl) 1(1,2,3,4,5,6-pi)-(l-methylethyl)-benzene]-iron II hexafluorophosphate (0.5 part), ben7ildimethylketal (0.5 part), Orasol Red G (0.04 part) and acetone (0.5 part) i8 stirred until a solution is obtained.

The mixture is coated onto copper-clad laminate in a layer 36 micro-metres thick and the coating solidified by irradiation using a 500 W
tungsten-halogen lamp at a distance of 20 cm for 30 seconds followed by heatlng at 90C for 5 minutes. The solidified coating is then irradiated through a transparency using a 5000 W metal halide lamp at a di~tance of 75 cm for 30 seconds. Development in propylene carbonate produces a negative image of the transparency.

1 31 ~592 -- 40 ~
Example_14_ A mixture of Resin 2 ~7 part~), Resin 8 ~3 parts), (pi-2,4-cyclopentadiene-1-yl) [(1,2,3,4,5,6-pi)-(1-methylethyl)-benzene]-iron II hexafluorophosphate (0.3 part), benzildimethyl-ketal (0.3 part) and acetone (1 part) i8 stirred until a solution i~
obtained.

The mixture 1~ coated onto copper-clad laminate in a layer 12 micro-metres thick and the coating solidified by irradiation using a 500 W
tungsten-lamp at a distance of 20 cm for 300 seconds followed by heating at 90C for 5 minutes. The solidified coating i~ then irradiated through a transparency using a 5000 W metal halide lamp at a distance of 75 cm for 120 seconds. Development in a 8:2 v/v mixture of toluene and tetrahydrofuran produces a negaeive image of the transparency.

Example 15: A mixture of Resin 5 (1 part), Resin 4 (1 part), Resin 9 (1 part), (piS-2,4-cyclopentadien-1-yl) [(1,2,3,4,5,6-pi)-(1-methyl-ethyl)-benzene~-iron II hexafluorophosphate (0.1 part), benzildi-methylketal (0.1 part), anthracene ~0.05 part) and acetone (0.3 part) i~ stirred until a homogeneous mlxture i~ obtained.

The mixture is coated onto copper-clad laminate ln a layer 12 micro-metres thick and the coating solidified by irradiatlon using a 500 W
tungsten-halogen lamp at a distance of 20 cm for 5 minutes followed by heating at 90C for 5 minutes. The solidifled coating is then irradiated through a transparency using a 5000 W metal halide lamp at a distance of 75 cm for 2 minutes. Development in a 6:4 vlv mixture of ethanol and acetone produces a negative image of the transparency.

Example 16: A mixture of Resin 5 (5 parts), Re~in 2 (5 parts), (piS-2,4-cyclopentadien-1-yl) ~(1,2,3,4,5,6-pi)-(1-methylethyl)-benzenel-iron II hexafluorophosphate (0.5 part), 2~methyl-1-(methyl-thio)phenyl-2-morpholinopropan-1-one (0.5 part) and acetone (1 part) is ~tirred until a solution i~ obtained.

- 41 - 1 3 1 5 ~92 The mixture is coated onto copper-clad laminate in a layer 12 micro-metres thick and the coating solidified by irradiation using a 500 W
tungsten-halogen lamp at a distance of 20 cm for 3 minutes followed by heating at 90C for 5 minutes. The solidified coating is then irradiated through a transparency using a 5000 W metal halide lamp at a distance of 75 cm for 2 minutes. Development in a 6:4 v/v mixture of 1,1,1-trichloroethane and acetone produces a negative image of the transparency.

Example 1?: A mixture of Resin 2 (6 parts), Resin 10 (4 parts), (piS-2,4-cyclopentsdien-1-yl) [(1,2,3,4,5,6-pi)-(1-methylethyl)-benzene]-iron II hexafluorophosphate (0.5 part), benzildimethylketal (0.5 part) and acetone (1 part) is stirred until a solution is obtained.

The mixture is coated onto copper-clad laminate in a layer 36 micro-metres thick and the coating solidified by irradiation using a 500 W
tungsten-halogen lamp at a distance of 20 cm for 10 minutes followed by heating at 120C for 5 minutes. The solidified coating is then irradiated through a transparency using a 5000 W metal halide lamp at a distance of 75 cm for 2 minutes. Development in a mixture of propylene carbonate (5 parts), butyl digol (3 parts) and gamma butyrolactone (2 parts) produces a negative image of the trans-parency.

Example 18: A mixture of Resin 1 (5 parts), Resin 2 (5 part~)~
(piS-2,4-cyclopentadienyl) (pi6-trans stilbene) iron II hexafluoro-phosphate (0.5 part), benzildimethylketal (0.5 part) and acetone (1 part) is stirred until a solution is obtained.

The mixture is coated onto copper-clad laminate in a layer 36 micro-metres thick. The coated laminate is then irradiated using a 500 W
tungsten-halogen lamp with a filter to cut out irradiation below 450 nm at a distance of 20 cm for 10 minutes and hested at 120C for 10 minutes to give a tack-free film. The solidified coating is then irradiated through a transparency using a 5000 W metal halide lamp 131~592 producing radiaton within a wavelength at 340-450 nm, at a distance of 75 cm for 2 minutes. Development in a mixture of propylene carbonate (5 parts), butyl digol (3 parts) and gamma butyrolactone (2 parts) produces a negative image of the transparency.

Example 19: A mixture of Resin 11 (2.5 parts), (piS-2,4-cyclopenta-dienyl-1-yl) [(1,2,3,4,5,6-pi)-(1-methylethyl)-benzene~-iron II
hexafluorophosphate (0.125 parts) are mixed until homogeneous.

The mixture is coated onto copper-clad laminate in a layer 36 micro-metres thick and the coating solidified by irradiation using a 500 W
tungsten-halogen lamp at a distance of 20 cm for 10 minutes followed by heat at 120C for 5 minutes. The solidified coating i8 then irradiated through a transparency using a 5000 W metal halide lamp at a distance of 75 cm for S minutes. This is then heated at 90C
for 5 minutes and developed in 1,1,1-trichloroethane to give a negative image of the transparency.

A mixture of Resin 2 (2.5 parts), Resin 11 (0.5 parts), Resin 12 (2.0 parts), ~(pi5-2,4-cyclopentadien-1-yl) (1,2,3,4,5,6-pi)-(l-methylethyl)-benzene]-iron II hexafluorophosphate (0.25 parts), benzildimethylketal (0.08 parts) and acetone (0.25 parts) is stirred until a solution i8 obtained.

The mixture is coated onto copper-clad laminate in a layer 36 micro-metres thick and the coating solidified by irradiation using a 500 W
tungsten-halogen lamp at a distance of 20 cm for 8 minutes followed by heat at 120C for 10 minutes. The solidified coating i~ then irradiated through a transparency using a 5000 W metal halide lamp at a distance of 75 cm for 2 minutes. Development in a mixture of propylene carbonate (5 parts), butyl digol (3 parts) and gamma butyrolactone (2 parts) produces a negative image of the trans-parency.
.

Claims (18)

1. A process for the production of an image which comprises (i) applying to a substrate a layer of a liquid composition comprising:
(A) a cationically polymerisable residue;
(B) a radiation-activated polymerisation initiator for (A); and (C) a radiation-curable residue that is different from (A);
(D) a radiation-activated initiator for the cure of (C);
with the proviso that the residue (C) may or may not be accompanied with the initiator (D);
(ii) subjecting the composition to actinic radiation having a wavelength at which initiator (B) is activated but at which the residue (C) and/or initiator (D) is not substantially activated, so that (A) is polymerised and the layer of liquid composition is solidified, but remains photocurable, (iii)subjecting the solidified layer in a predetermined pattern to actinic radiation having a wavelength that is different from that of the radiation using in stage (ii) and at which the radiation curable residue (C) and/or the initiator (D) is activated, such that in the exposed areas (C) is substantially cured, and (iv) removing areas of the solidified layer that have not been substantially cured.

-43a- 21489-7145

2. A process as claimed in claim 1 in which the liquid composition comprises one or more substances that are cationically polymerised, together with one or more substances that are polymerised by exposure to actinic radiation only at a shorter wavelength than that used to activate the polymerisation initiator (B).

3. A process as claimed in claim 1 in which the liquid composition comprises one or more dual-functional substances having in the same molecule two types of photopolymerisation function, one of which is activated only by irradiation at a wavelength that is different from that at which the polymerisation initiator (B) is activated.

4. A process as claimed in claim 1 in which residue (A) is a 1,2-epoxide, a vinyl ether or a mixture thereof.

5. A process as claimed in claim 4 in which residue (A) is a glycidyl ether of an alcohol or phenol, a cycloaliphatic epoxide resin, a glycidyl ester, or a vinyloxyalkyl ether of a phenol.

6. A process as claimed in claim 1 in which the polymerisation initiator (B) is at least one compound of the formula (I) R?an [LQm]?q (I) wherein L is a divalent to heptavalent metal or non metal, Q is a halogen atom or one of the groups Q may be a hydroxyl group, q is an integer from 1 to 3, m is an integer corresponding to the valency of L+q, a is 1 or 2, n is an integer from 1 to 3 and R is an ion selected from:
(i) Ar-I+-Ar' wherein Ar and Ar' are substituted or unsubstituted aromatic radicals;

(ii) [Y-Z-(CO)x]+

wherein Y represents an arene or dienylium group; Z represents an atom of a d-block transition element chosen from titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, niobium, molyb-denum, ruthenium, rhodium, palladium, silver, tantalum, tungsten, rhenium, osmium, iridium, platinum and gold; and x is a positive integer such that the atom Z has a closed shell electron configura-tion;
(iii) aromatic diazonium ions;
(iv) [(R1)(R2M)a]+an wherein a and n are as defined above, M is the cation of a mono-valent to trivalent metal from groups IVb to VIIb, VIII or Ib of the Periodic Table; R1 is a .pi.-arene and R2 is a .pi.-arene or the anion of a .pi.-arene;
(v) aromatic sulphonium ions; or (vi) aromatic sulphoxonium ions.

7. A process as claimed in claim 6 in which the cation R?an of the polymerisation initiator (B) has the formula (iv) as defined in claim 6.

8. A process as claimed in claim 7 in which the composition also contains an organic peroxide or hydroperoxide or quinone.

9. A process as claimed in claim 7 in which the first irradiation is followed by heating to polymerise residues (A).

10. A process as claimed in claim 7, wherein M is a chromium, cobalt, manganese, tungsten, molybdenum or iron cation and in which the ion [LQm]-q is selected from BF4-, PF6-, AsF6-, SbF6-, SbF5(OH)-, FeCl4-, SnCl6-, SbCl6- and BiCl6-.

11. A process as claimed in claim 1 in which curable residue (C) is a material having at least two groups which are azido, coumarin, stilbene, maleimido, pyridinone, chalcone, propenone, pentadienone, anthracene or .alpha.,.beta.-ethylenically unsaturated ester groups having aromaticity or ethylenic unsaturation in conjugation with the .alpha.,.beta.-unsaturation, or is a cationically polymerisable residue as defined for residue (A).

12. A process as claimed in claim 11 in which curable residue (C) is an acrylic ester containing at least two groups of formula VII
CH2=CR3-COO- (VII) where R3 represents a hydrogen or chlorine atom or a methyl or ethyl group.

13. A process as claimed in claim 11 in which residue (C) is a 1,2-epoxide.

14. A process as claimed in claim 1 in which initiator (D) is selected from the group consisting of a benzoin ether, acyloin ether, halogenated alkyl or aryl derivative, aromatic carbonyl derivative, a metallocene, a mixture of a Group IV A metal organo-metallic compound with a photoreducible dye, a mixture of a quinone and an aliphatic amine having hydrogen attached to an aliphatic alpha carbon atom, an aliphatic dicarbonyl compound optionally mixed with an amine, a 3-ketocoumarin, an acyl-phosphine oxide, a metal carbonyl, an onium salt, or a mixture of a photoreducible dye with a reducing agent.

15. A process as claimed in claim 1 in which the weight ratio of cationically polymerisable residue (A) to radiation curable residue (C) is within the range 1:0.1-10 and in which 0.1 to 50 parts by weight of initiator (B) are present per 100 parts by weight of polymerisable residue (A).

16. A process as claimed in claim 1 in which step (ii) consists in subjecting the composition to actinic radiation having a wavelength at which initiator (B) is activated but at which the residue (C) and/or initiator (D) is not substantially activated, followed by heating, so that (A) is polymerised and the layer of liquid composition is solidified, but remains photocurable.

17. A liquid composition, suitable for use in a process as claimed in claim 1 which comprises:
(A) a cationically polymerisable residue;
(B) a radiation-activated polymerisation initiator for (A); and (C) a radiation-curable residue that is different from (A);
(D) a radiation-activated initiator for the cure of (C);
with the proviso that the residue (C) may or may not be accompanied with the initiator (D);
the radiation curable residue (C) and/or initiator (D) being activated by irradiation at a different wavelength from that which activates initiator (B).

18. A composition as claimed in claim 17 which comprises:
(A) a cycloaliphatic epoxide;
(B) a salt as defined in claim 7, where the anion is BF4- or PF6-;
(C) a glycidyl ether; and (D) an onium salt.