Abstract: The invention concerns iodonium salts of the general formula A-I.sup.+ --B X.sup.-, in which A is a group of the general formula ##STR1## in which C is a monovalent aromatic hydrocarbon group with 6 to 14 carbon atoms or a monovalent aromatic hydrocarbon group containing at least one oxygen and/or sulphur atom and with 5 to 14 atoms in the aromatic ring, D, E and F are each substituents of C, D being a group of the formula --(O).sub.x --(R).sub.y --SiR1/3, E being a group of the formula --OR.sup.2, F being a group of the formula --R.sup.3, a being 1, 2, or 3, b being 0, 1 or 2, c being 0, 1 or 2, x being 0 or 1 and y being 0 or 1, and R, R.sup.1, R.sup.2 and R.sup.3 are as defined in claim 1; B is a group of the formula ##STR2## in which E and F, which are as defined above, may each be bound to the 2, 3, 4, 5 or 6 position in the benzene ring, d is 0, 1 or 2, e is 0, 1 or 2 and X.sup.- is a tosylate anion or a weakly nucleophilic or non-nucleophilic anion Y.sup.- selected from the group comprising CF.sub.

Abstract: Aminoketone-substituted coumarin sensitizers having quaternary amine substituents are described which have very high photosensitivity, and are useful in moderate pH aqueous-developable printing plates. The aminoketone-substituted coumarin sensitizers are described by the formula: ##STR1## wherein R.sub.1 and R.sub.2 each represent an alkyl group having 1 to 6 carbon atoms, and R.sub.3 and R.sub.4 each represent hydrogen; or at least one of R.sub.1 and R.sub.3 or R.sub.2 and R.sub.4 together represent an alkylene group having 2 to 4 carbon atoms,R.sub.5 represents an alkyl group having 1 to 6 carbon atoms or H,R.sub.6 represents an alkylene group having 1 to 16 carbon atoms, an oxyalkylene group having form 1 to 16 carbon atoms, or a poly(oxyalkylene) group in which said alkylene group has 2 to 4 carbon atoms and the number of oxygen atoms is a positive integer less than or equal to four,R.sub.7, R.sub.8, and R.sub.9 each independently represent an alkyl group having 1 to 6 carbon atoms, or any two of R.sub.

Abstract: A reaction resin mixture, which is able to be hardened thermally and by means of UV radiation, contains the following constituents:a cationically polymerizable epoxide resin;a latent hardening initiator in the form of an aralkyl-thiolanium salt; anda sensitizer of the structure ##STR1## A being --CO--, --NR-- and --CO--CO--, and D being --O--, --S--, --CO-- and --CH.sub.2).sub.x (where x= 1 or 2) or rather a single bond or two hydrogen atoms.

Abstract: Novel photosensitive compositions based on azlactone derived polymers are described. The polymers have a hydroearbyl backbone and pendant peptide groups with free-radically polymerizable functionality attached thereto, said polymer further comprising at least one oxyacid group or salt thereof, and optionally quaternary ammonium salt groups. A high speed durable printing plate having a mild pH aqueous developability is disclosed which incorporates these polymers in combination with a photoinitiator. The polymers are also useful as proofing films in graphic arts applications.

Abstract: The present invention relates to a resin composition for optical molding which comprises (a) an actinic radical-curable and cationically polymerizable organic substance and (b) an actinic radiation-sensitive initiator for cationic polymerization. This composition can be cured without being affected by atomospheric oxygen.

Abstract: A photo-crosslinkable resin composition comprises (a) a polymer having an electron-donating group in a monomer unit, (b) a halogen compound, (c) an onium salt and (d) at least one sensitizer selected from the group consisting of coumarin derivatives, rhodanine derivatives, thioxanthene derivatives and unsaturated cyclopentanone compounds. The composition can be used as a hologram recording medium.

Abstract: Aminoketone-substituted coumarin sensitizers having tethered tertiary amino groups are described which have extremely good photosensitivity. The sensitizers of the instant invention have the formula: ##STR1## wherein R.sub.1 and R.sub.2 each represent an alkyl group having 1 to 6 carbon atoms, and R.sub.3 and R.sub.4 each represent hydrogen; or at least one of R.sub.1 and R.sub.3 or R.sub.2 and R.sub.4 together represent an alkylene group having 2 to 4 carbon atoms,R.sub.5 represents an alkyl group having 1 to 6 carbon atoms or H,R.sub.6 represents an alkylene group having 1 to 6 carbon atoms, andR.sub.7 and R.sub.8 each independently represent an alkyl group having 1 to 6 carbon atoms, both of R.sub.7 and R.sub.8 taken together represent an alkylene group having 4 to 6 carbon atoms, or R.sub.5 or R.sub.6 taken together with R.sub.7 or R.sub.8 represent a five, six, or seven membered heterocyclic ring group.

Abstract: A photopolymerizable composition comprises: (i) a polymerizable compound carrying an addition-polymerizable unsaturated bond; (ii) a methine compound; (iii) at least one compound selected from the group consisting of: (a) compounds having carbon-halogen bonds, (b) aromatic onium salts, (c) organic peroxides, (d) thio compounds, (e) hexaaryl-biimidazoles, (f) ketooxime esters, and (g) compounds represented by the following general formula (III): ##STR1## wherein R.sup.6, R.sup.7, R.sup.8 and R.sup.9 may be the same or different and each represents a substituted or unsubstituted alkyl, aryl, alkenyl, alkynyl or heterocyclic group, provided that at least two of R.sup.6, R.sup.7, R.sup.8 and R.sup.9 may be bonded together to form a ring structure and that at least one of them represents an alkyl group; and Z.sup.+ represents an alkali metal cation or a quaternary ammonium cation. The composition has a high sensitivity to a wide range of actinic light rays extending from ultraviolet to visible light.

Abstract: This invention relates to radiation curable alk-1-enyloxy carbonate reaction products of a hydroxylated compound having the formula A-ROH and a dialk-1-enyloxy carbonate having the formula ##STR1## wherein R is a polymeric radical selected from the group of polyester, polyacetal, polyurethane, polyether, and polycarbonate, said polymers containing from about 10 to 50 repeating monomer units;A' is a terminating moiety and is hydrogen, lower alkyl or hydroxy;R' is hydrogen or lower alkyl;B is a linear, branched or cyclic divalent radicalhaving from 2 to 12 carbon atoms and is selected from the group of alkylene, mono or poly alkoxylated alkylene, alkenylene, alkynylene, arylene, alkarylene and aralkylene radicals, which radicals are optionally substituted with halo, lower alkyl, cyano, nitro or alkoxy and m has a value of from 1 to 10.

Abstract: A highly stable photopolymerizable composition which is highly photosensitive to visible light, which can be hardened using a visible light laser, such as an argon laser, which provides excellent contrast between non-irradiated portions and the substrate under red light, and, moreover, which provides excellent contrast between the portions irradiated by the laser and the portions not irradiated. The photopolymerizable composition consists of 100 parts by weight of a resin which is hardenable under visible light having an irradiation energy mainly consisting of light rays in the 400 nm to 700 nm visible light region; 0.02 to 0.5 parts by weight of at least one dye selected from the group consisting of Victoria Pure Blue, anthraquinone dyes, monoazo dyes, and merocyanine dyes, these dyes having maximum absorption wavelengths from 550 to 700 nm; 0.1 to 5 parts by weight of the leuco dye 4,4'-(phenylmethylene bis[N,N-diethylbenzene amine]; and 0.1 to 5 parts by weight of tribromomethylphenyl sulphone.

Abstract: A tough polymeric mixture comprises the polymerized product of admixture I or II, whereinadmixture I comprises 5 to 45 weight percent of a first monomer and a photoinitiator therefor, said first monomer being at least one free-radically polymerizable monomer, and 95 to 55 weight percent of a second monomer and a photoinitiator therefor, said second monomer being at least one set of polyurethane precursors, andadmixture II comprises 5 to 45 weight percent of a first monomer and a photoinitiator therefor, said first monomer being at least one set of polyurethane precursors, and 95 to 55 weight percent of a second monomer and a photoinitiator therefor, said second monomer being at least one free-radically polymerizable monomer,said polymeric mixture having been prepared by a process involving two sequential actinic radiations of wavelength ranges centered around .lambda..sub.1 and .lambda..sub.2, respectively, wherein .lambda..sub.1 and .lambda..sub.

Abstract: Novel photosensitive compositions based on azlactone derived polymers are described. The polymers have a hydrocarbyl backbone and pendant peptide groups with free-radically polymerizable functionality attached thereto, said polymer further comprising at least one oxyacid group or salt thereof, and optionally quaternary ammonium salt groups. A high speed durable printing plate having a mild pH aqueous developability is disclosed which incorporates these polymers in combination with a photoinitiator. The polymers are also useful as proofing films in graphic arts applications.

Abstract: The present invention relates to a photopolymerizable composition having a high sensitivity to visible light of 400 nm or longer and comprising a photopolymerization initiator consisting of:(a) a salt of an organic boron anionic compound with an organic and cationic dye or a combination of an organic and cationic dye with a salt of an organic boron anionic compound, and(b) a compound having the general formulae (I) to (VI) as defined in the present application.

Abstract: Acid sensitized photoresists with enhanced photospeed are provided. The photoresist compositions include a polymer binder and/or a polymerizable compound and an acid sensitive group which enables patterning of the resist composition, and acid generating photoinitiator, and an hydroxy aromatic compound which enhances the speed of the resist composition under imaging radiation.

Abstract: Photopolymerizable compositions in which the photoinitiator system contains a hexaarylbisimidazole and/or a p-dialkyaminophenyl carbonyl compound in combination with a borate anion coinitiator are disclosed.

Abstract: This invention relates to initiator systems for photopolymerizable compositions. More particularly, this invention pertains to photopolymerizable compositions in which the initiator system comprises an anionic dye in combination with a borate anion coinitiator.

Abstract: A radiation sensitive plate comprises a substrate coated with a photopolymerizable composition. The composition comprises a polymerizable compound containing ethylenic unsaturation, a perester photoinitiator and optionally an optical sensitiser. The substrate may be a sheet of grained and anodized aluminum and the plate is useful in the production of lithographic printing plates.

Abstract: A tough polymeric mixture comprises the polymerized product of admixture I or II, whereinadmixture I comprises 5 to 45 weight percent of a first monomer and a photoinitiator therefor, said first monomer being at least one free-radically polymerizable monomer, and 95 to 55 weight percent of a second monomer and a photoinitiator therefor, said second monomer being at least one set of polyurethane precursors, andadmixture II comprises 5 to 45 weight percent of a first monomer and a photoinitiator therefor, said first monomer being at least one set of polyurethane precursors, and 95 to 55 weight percent of a second monomer and a photoinitiator therefor, said second monomer being at least one free-radically polymerizable monomer,said polymeric mixture having been prepared by a process involving two sequential actinic radiations of wavelengths ranges centered around .lambda..sub.1 and .lambda..sub.2, respectively, wherein .lambda..sub.1 and .lambda..sub.

Abstract: A composition for visible light sensitive electrodeposition coating which comprises (A) a photocurable resin having light sensitive groups capable of being crosslinked or polymerized by light irradiation and ionic groups, (B) a sensitizer which is excited by absorption of visible light and has a property to interact with the resin (A), (C) a water-insoluble polymerization initiator, and optionally, (D) at least one specific nitrogen-containing compound; and an image-forming method which comprises (i) coating the surface of a conductor by electrodeposition with the aforesaid composition, (ii) exposing the resulting film by electrodeposition by partially irradiating the film with visible light, and then (iii) contacting the resulting film with a developing solution to remove the unexposed areas.

Abstract: A photohardenable composition comprising an addition polymerizable or crosslinkable material, a photoinitiator composition capable of initiating polymerization or crosslinking of said polymerizable or crosslinkable material, and a compound of the formula ##STR1## wherein Q represents --C.dbd.O or --C--OH; X represents S or N which is unsubstituted or substituted with alkyl or aryl groups;R.sub.1 represents H, alkyl, aryl, alkoxy, bezoyl, arloxy, acyl or monosubstituted amino groups; andR.sub.2 represents H, alkyl or aryl groups is disclosed. The composition is preferably contained in microcapsules and is used in photosensitive imaging systems. The five member aromatic group containing the imine moiety functions to reduce the likelihood of short time scale reciprocity failure of the composition and enable imaging using high intensity radiation sources. An imaging method using the inventive composition is also disclosed.

Abstract: Synthesis use of a new class of diaryliodonium salt photo and thermal polymerization initiators in which the aryl groups are substituted with alkoxy group bearing hydroxy groups. Good to excellent yields are obtained of diaryliodonium salts in which the aryl groups are substituted with long chain alkoxy groups, which alkoxy groups also possess at least one hydroxyl moiety attached at the 2-position of an alkoxy group. The resultant salts have enhanced solubility when compared with their lower molecular weight counterparts. The hydroxyl groups serve as chain transfer agents; and, in cross linking UV-induced cationic polymerizations, the hydroxyl groups effect marked accelertion on polymerization rates. The salts also have excellent compatability with nonpolar monomers such as epoxidized oil and poly(1,2-butadience oxide) and provide further benefits when they are used along with copper cocatalysts in thermally curable polymer systems.

Abstract: A photohardenable composition comprising a free radical addition polymerizable or crosslinkable compound and an aromatic ketone and a borate salt; and photosensitive materials employing the composition where in one embodiment the composition is microencapsulated.

Abstract: A photopolymerizable composition comprising (i) a polymerizable compound having an addition polymerizable unsaturated bond, (ii) a compound represented by formula (Ia): ##STR1## a compound represented by formula (Ib): ##STR2## or a compound represented by formula (Ic): ##STR3## wherein A represents an oxygen atom, a sulfur atom, a selenium atom, a tellurium atom, an alkyl- or aryl-substituted nitrogen atom, or a dialkyl-substituted carbon atom; Y.sup.1 represents a hydrogen atom, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, an aralkyl group, an acyl group, an alkoxycarbonyl group, or a substituted alkoxycarbonyl group; R.sup.1 and R.sup.2 each represents a hydrogen atom, an alkyl group having from 1 to 18 carbon atoms, or an alkyl group having from 1 to 18 carbon atoms which is substituted with R.sup.3 O--, ##STR4## or a halogen atom (i.e., F, Cl, Br, and I), wherein R.sup.

Abstract: A new polymer family is shown for use in high speed photoresists. A dry film photoresist includes a polymer binder prepared from t-butyl methacrylate/methylmethacrylate/acrylic acid/ethyl acrylate and a suitable initiator.

Abstract: This invention relates to a cross-linkable, cationic radiation curable composition comprising (a) a non-volatile vinyl ether, epoxide, acrylate or an oligomer thereof (b) a cationic photoinitiator and (c) a divinyl ether polyacetal oligomer having the formula ##STR1## wherein n has a value of from 1 to 50;X is uniformly sulfur or oxygen;R is C.sub.2 to C.sub.4 alkeneoxy alkylene, poly(alkyleneoxy) alkylene, or a branched, linear or cyclic C.sub.2 to C.sub.20 alkylene andR' is phenylene, diphenylene methane, diphenylene propane, xylylene, tolylene, or a branched, linear or cyclic C.sub.2 to C.sub.20 alkylene optionally substituted with an ether, ester, carbonate, carbamate, C.sub.2 to C.sub.4 alkyleneoxy alkylene or poly(C.sub.2 to C.sub.4 alkyleneoxy) alkylene radical. The invention also relates to the composition cured on a substrate.

Abstract: A polymerizable composition comprises a polymeric precursor selected from the group consisting of (1) at least one ethylenically-unsaturated monomer, optionally in combination with an epoxy monomer or polyurethane precursors, or (2) at least one epoxy monomer, or (3) polyurethane precursors, and a curing agent comprising an organometallic salt and an onium salt.

Abstract: Disclosed is a photopolymerizable composition which is very sensitive to visible light. The composition comprises a polymerizable compound and a photopolymerization initiator wherein the photopolymerization initiator comprises (A) a particular xanthene, coumarin or merocianine dyestuff, (B) a diaryliodonium salt and (C) a compound having the formula; R(n)--D--CH.sub.

Abstract: Novel photopolymerizable recording materials suitable in particular for producing photoresist layers and lithographic printing plates are composed of one or more photopolymerizable, olefinically unsaturated organic compounds, optionally a polymeric binder, a photopolymerization initiator, a color-forming system composed of a color former and a photooxidant, a certain benzotriazole compound as a sensitizer and optionally further additive and/or auxiliary substances.

Abstract: Photopolymerizable compositions comprising:(1) at least one vinyl monomer capable of undergoing free radical polymerization,(2) a visible light or ultraviolet light responsive photoinitiator system comprising:(a) a diaryliodonium salt,(b) a pigment, insoluble in the photopolymerizable composition, said pigment also serving as a sensitizer,(c) one or more electron donating compounds, and, optionally,(3) adjuvants.The three component photoinitiator system of this invention can increase, by several orders of magnitude, the rate of ultraviolet light or visible light photocuring of vinyl monomers.

Abstract: Free radical polymerizable compositions contain a sulfonium salt which is tethered to at least one of an electron donor and a sensitizer, and a polymerizable monomer, demonstrate substantially enhanced photosensitivity. This invention also provides layered structures comprising a substrate coated with a free radical polymerizable composition containing a sulfonium salt which is tethered to at least one of an electron donor and a sensitizer, and the polymerized layered structures. A method for the preparation of certain tethered sulfonium salts is described.

Abstract: A photopolymerizable composition is provided containing a polymerizable compound having an ethylenically unsaturated bond, a photopolymerization initiator, and if necessary, a linear organic high molecular weight polymer. The photopolymerization initiator comprises a combination of (a) an organic compound represented by formula (I): ##STR1## wherein R.sup.1, R.sup.2, R.sup.3, and R.sup.4, which may be the same or different, each represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted alkenyl group a substituted or unsubstituted alkynyl group, or a substituted or unsubstituted heterocyclic group, and at least two of said R.sup.1, R.sup.2, R.sup.3, and R.sup.4 may combine to form a cyclic structure, with the proviso that at least one of R.sup.1, R.sup.2, R.sup.3, and R.sup.4 is an alkyl group, and wherein Z.sym. represents an alkali metal cation or a quaternary ammonium cation, and (b) an organic dye having no counter anion.

Abstract: A B stageable thermosettable composition containing at least one polyepoxide and at least one linear anhydride monomer capable of forming a cyclopolymer in situ and processes for the formation of the B stage intermediate and final thermoset having a high service temperature is provided. The composition is useful in a two stage process; first to form a storage stable, flowable thermoplastic B stage intermediate by the free radical initiated vinyl polymerization of the linear anhydride in the liquid composition to a cyclic polymer and secondly to react the cyclic polymer with the poly epoxide to form a crosslinked high service temperature theremoset useful in the preparation of laminates, such as printed circuit boards, adhesives, and encapsulants.

Abstract: Novel photopolymerizable recording materials suitable in particular for producing photoresist layers and lithographic printing plates are composed of one or more photopolymerizable, olefinically unsaturated organic compounds, optionally a polymeric binder, a photopolymerization initiator, a color-forming system composed of a color former and a photooxidant, a certain 4-phenylpyridine as sensitizer and optionally further additive and/or auxiliary substances.

Abstract: Described herein are compositions suitable for photocopolymerization comprising a cyclic vinyl ether containing compound and urethane acrylates. Photocurable coatings can be prepared from such composition and such coatings have markedly improved flexibility and impact resistant properties.

Abstract: Abstract of the disclosure: Novel photopolymerizable recording materials suitable in particular for producing photoresist layers and lithographic printing plates are composed of one or more photopolymerizable, olefinically unsaturated organic compounds, a photopolymerization initiator, a color-forming system composed of a color former and a photooxidant, novel 4-quinazolone compounds as sensitizers of the formula (I) ##STR1##

Abstract: Photopolymerizable compositions comprising:(1) at least one vinyl monomr capable of undergoing free radical polymerization,(2) a visible light or ultraviolet light responsive photoinitiator system comprising:(a) a diaryliodonium salt,(b) a pigment, insoluble in the photopolymerizable composition, said pigment also serving as a sensitizer,(c) one or more electron donating compounds, and, optionally,(3) adjuvants.The three component photoinitiator system of this invention can increase, by several orders of magnitude, the rate of ultraviolet light or visible light photocuring of vinyl monomers.

Abstract: A method is provided for coating a substrate with a non-toxic irradiation curable epoxy resin composition. There is used an alkoxy-substituted aryl onium salt, in combination with a non-toxic oxirane-containing organic or silicone resin.

Abstract: Disclosed is a photopolymerizable composition which is very sensitive to visible light. The composition comprises a polymerizable compound and a photopolymerization initiator wherein the photopolymerization initiator comprises (A) a particular xanthene, coumarin or merocianine dyestuff, (B) a diaryliodonium salt and (C) a compound having the formula;R(n)--D--CH.sub.

Abstract: The invention provides 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 polymerizable residue(B) a radiation-activated polymerization initator 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 polymerized and the layer of liquid composition is solidified, but remains curable,(iii) subjecting the solidified layer in a predetermined 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) re

Abstract: Photosensitive iodonium polymers are provided useful as positive photoresists. The iodonium polymers can be converted to polymeric diaryl iodonium polyfluorometal and metalloid salts by a metathesis reaction. These polymeric iodonium polyfluorometal and metalloid salts can be used as a catalyst in combination with a copper compound cocatalyst to make heat curable compositions with cationically polymerizable materials such as an epoxy resin.

Abstract: A photopolymerizable epoxy resin composition comprising (a) an epoxy resin and (b) a heteropoly-acid aromatic sulfonium salt or a heteropoly-acid aromatic iodonium salt as a photocuring catalyst exhibits rapid photopolymerization, with the cured product being great in hardness, the corrosive action being weak, and the electrical properties being excellent. The industrial utility of the composition is therefore substantial.

Abstract: This invention describes the use of some Mannich bases as photosensitizers for iodonium salts for use in the initiation of free radical polymerization of vinyl monomers. These Mannich bases are unexpectedly more efficient as photosensitizers than are the conventional photosensitizers.

Abstract: Spectral sensitizing dyes which sensitize photoinitiators and disperse in aqueous solutions are desirable in photosensitive systems where precise color rendition is important.

Abstract: Mixtures which are curable by heating or irradiation with actinic light contain one or more cationically curable compounds, such as an epoxy, an olefinically unsaturated monomer, amino resin or phenolic resin, and as a cationically active curing catalyst one or more N-sulfonylamino-sulfonium salts of the formula ##STR1## such as N-p-toluenesulfonyl-N-methylaminodiphenylsulfonium hexafluorophosphate with or without quinones or peroxides are suitable, inter alia, for producing moldings, coatings, relief images and resist patterns.

Abstract: A photopolymerizable composition comprises a polymerizable epoxy-containing material, a polymerizable monomer or monomers containing one or more ##STR1## groups wherein R is H or CH.sub.3, a cationic photoinitiator, a radical-type photoinitiator and an alcohol accelerator.

Abstract: Photosensitive film which is photosensitive in a given wavelength range comprises at least one silicon-containing polymer, at least one salt which can be converted into a Brunsted acid by irradiation and optionally at least one photosensitizer. The silicon-containing polymer-based photosensitive film can be used as a masking resin in a lithography process for producing electronic components.

Abstract: Semi-interpenetrating polymer networks which may be used as printing inks or as coatings are prepared by subjecting a mixture of a vinyl ether and a cellulose ester to irradiation from an electron beam. This mixture is curable with low energy dosages ranging from about 0.1 to about 10.0 Mrads, and from about 150 to about 300 Kev. The reaction is effected in the presence of a polymerization catalyst comprising an onium salt.

Abstract: A process for the production of a protective layer or a relief image on a substrate, wherein a radiation-sensitive layer, consisting of a solid film-forming epoxy resin containing a photoinitiator, which can be activated by radiation, for the polyaddition reaction, is transferred from a support to a substrate, then exposed directly or under a photomask and hardened by the action of heat, after which, if appropriate, the unexposed parts are developed with a solvent. The process is suitable, for example, for the production of printed circuits, solder resist masks and offset printing plates.

Abstract: A radiation-curable composition suitable for use as a protective coating for a photographic element comprises a polymerizable acrylic compound, a polymerizable epoxy-functional silane compound, a free-radical photoinitiator capable of initiating polymerization of said acrylic compound, and 0 to 2 percent of the total composition on a weight basis of a cationic photoinitiator capable of initiating polymerization of said epoxy-functional silane compound, said composition containing epoxy functionality only in a silane compound.

Abstract: Polymerizable compositions contain (A) a cationically polymerizable material, such as an epoxide resin, a phenoplast or a cyclic vinyl ether, (B) a hydroxy compound such as styreneallyl alcohol copolymer, and (c) an aromatic iodosyl salt of formula ##STR1## where R.sup.3 and R.sup.4, which may be the same or different, each represent a monovalent aromatic radical having from 4 to 25 carbon atoms, x denotes 1, 2 or 3, and Z.sup.x- denotes an x-valent anion of a protic acid.Suitable salts of formula II include diphenyliodosyl hexafluorophosphate and tetrafluoroborate. The compositions may be photopolymerized or they may be thermally polymerized in the presence, as catalyst for the iodosyl salt, of a salt or complex of a d-block transition metal, a stannous salt, an organic peroxide or an activated .alpha.-hydroxy compound.The compositions may be used as surface coatings and adhesives, and in the preparation of printing plates, printed circuits and reinforced composites.