Abstract: A photopolymerizable composition comprising an addition-polymerizable compound having at least one ethylenic unsaturated double bond, at least one specific sensitizing dye such as the following formula (I), and a titanocene compound: ##STR1## The substituents in formula (I) are defined in the specification.

Abstract: A free radical polymerization process for the preparation of polymer comprising:a first heating and photoinitiating with ultraviolet light of a mixture comprised of a stable free radical agent, and at least one polymerizable monomer compound;optionally cooling said mixture;a second heating of said mixture at a temperature of from about 100.degree. C. to about 160.degree. C.;isolating the polymer product formed; andoptionally washing and drying said polymer.

Abstract: A photopolymerizable composition is described, comprising components (i) a compound having at least one addition-polymerizable ethylenically unsaturated bond, (ii) a compound represented by the following formula (I): ##STR1## and (iii) an activating agent which generates an active radical upon light irradiation in the co-presence of component (ii). The substituents in formula (I) are defined in the specification.

Abstract: A photopolymerizable composition is disclosed, which comprises an addition-polymerizable compound having at least one ethylenically unsaturated double bond, a sensitizing dye represented by the following formula (I): ##STR1## wherein the all symbols are defined in the disclosure, and a titanocene compound.

Abstract: A surface-coated vessel or a surface-coated product having a hard coating layer is obtained, by coating a substrate of, for example, resin product with a resin composition for hard coating which comprises(a) a poly?(meth)acryloyloxyalkyl!(iso)cyanurate represented by the following general formula (1) or (2): ##STR1## wherein X.sup.1, X.sup.2 and X.sup.3 are each an acryloyl group, methacryloyl group, hydrogen atom or an alkyl group, with a proviso that at least two of them are (meth)acryloyl groups, and R.sup.1, R.sup.2 and R.sup.3 are each an oxyalkylene group or a polyoxyalkylene group;(b) a poly(meth)acrylated polyoxyalkane polyol;(c) a photopolymerization initiator consisting of 2-methyl-1-?4-(methylthio)phenyl!-2-morpholino-1-propanone;(d) a photopolymerization initiator based on thioxanthone;(e) a UV-absorber based on monohydroxybenzophenone;(f) an organic solvent.

Abstract: A photopolymerizable composition is disclosed, comprising an addition polymerizable compound having at least one ethylenically unsaturated double bond, a sensitizing dye represented by formula (I) and a titanocene compound. The photopolymerizable composition exhibits high sensitivity to active light rays over a wide region of from ultraviolet light to visible light.

Abstract: A photo-curing composition including an image forming material, an ethylenically unsaturated monomer which is curable by polymerization thereof, a polymerization initiator which initiates the polymerization of the monomer, and two or more photosensitizers each of which absorbs a light and thereby causes the polymerization initiator to initiate the polymerization of the monomer, the photosensitizers having different maximum absorption wavelengths, respectively. A photosensitive capsule including a core material including the photo-curing composition, and a shell material within which the core material is encapsulated.

Abstract: The present invention relates to a photopolymerizable composition comprising squarylium compound represented by the formula (I): ##STR1## wherein R represents lower alkyl having 2 to 8 carbon atoms, a radical generator and an addition-polymerizable compound having at least one ethylenic unsaturated double bond.

Abstract: Resin compositions useful for filament winding applications comprising an epoxy component including at least one polyepoxide resin curable by heat, an olefinicially unsaturated monomer component including at least one polyolefinically unsaturated monomer curable by actinic radiation, at least one photoinitiator which is not a peroxide, at least one organic peroxide, and a heat activated curing agent for epoxides. The compositions have a viscosity less than about 2000 centipoise (cps) and are capable of retaining this viscosity for at least about 2 hours at a temperature of from about ambient temperature to about 60.degree. C. The resins are capable of being immobilized by actinic radiation exposure and further heat cured without substantial resin drip. One or more organic peroxides are employed, selected from the group of organic peroxides having 10 hour decomposition half lives at temperatures of from about 50.degree. C. to less than about 104.degree. C.

Abstract: The present invention relates to an article comprising a substrate which has coated thereon a photopolymerizable epoxy composition containing a plurality of epoxides including at least one selected from the group consisting of bisphenol A epoxides and cycloaliphatic epoxides, and at least one aliphatic epoxide, from about 0.1% to about 2% of at least one organometallic cationic initiator capable of initiating polymerization at wavelengths of from about 200 to about 600 nm, and optionally at least one accelerating agent. The article can be a flexible tape backing or a chip-resistant paint.

Abstract: A pressure-sensitive adhesive having excellent heat resistance, comprising a photopolymerization product of a composition comprising;a) 100 parts by weight of a monomer mixture comprising from 70 to 100% by weight of a (meth)acrylic acid alkyl ester having from 2 to 14 carbon atom on the average in the alkyl moiety and from 30 to 0% by weight of a monoethylenically unsaturated monomer copolymerizable with the (meth)acrylic acid alkyl ester,b) from 0.02 to 5 parts by weight of a polyfunctional (meth)acrylate as a crosslinking agent, andc) from 0.01 to 4 parts by weight of a photopolymerization initiator,wherein a content of the solvent-insoluble components is at least 60% by weight and a remaining amount of the unreacted monomers is less than 5,000 ppm.

Abstract: A photochromic composition which can be polymerized and cured upon irradiation with active energy rays such as ultraviolet rays to exhibit favorable photochromic property. The photochromic composition comprises 100 parts by weight of a radical polymerizable monomer, 0.001 to 0.2 parts by weight of a photochromic compound, and 0.01 to 1 part by weight of a photo polymerization 1.0 initiator. A photochromic cured product is obtained by irradiating the photochromic composition with the light which contains ultraviolet rays.

Abstract: There are disclosed herein a visible light sensitizer for a photopolymerizing initiator and/or a photocrosslinking agent which comprises a thiobarbituric acid derivative compound of the general formula (A) or (B): ##STR1## a photopolymerizable and/or a photocrosslinkable composition in which the thiobarbituric acid derivative compound is used, and a hologram recording medium in which the composition is used.

Abstract: A photopolymerizable composition is disclosed, comprising (i) a compound having at least one addition-polymerizable, ethylenically unsaturated bond; (ii) a compound represented by formula (IA) or (IB): ##STR1## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.9, R.sup.10, R.sup.11 and R.sup.12 each independently represents a hydrogen atom, a halogen atom, an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, a hydroxyl group, a substituted oxy group, a mercapto group, a substituted thio group, an amino group, a substituted amino group, a substituted carbonyl group, a sulfo group, a sulfonato group, a substituted sulfinyl group, a substituted sulfonyl group, a phosphono group, a substituted phosphono group, a phosphonato group, a substituted phosphonato group, a cyano group or a nitro group or R.sup.1 and R.sup.2, R.sup.2 and R.sup.3, R.sup.3 and R.sup.4, R.sup.9 and R.sup.10, R.sup.10 and R.sup.11 or R.sup.11 and R.sup.

Abstract: The sensitivity of a photoresist to actinic light is improved by the addition of certain dyes. The photoresist includes a polymer matrix, a photosensitive acid generator and at least one compound selected from the group consisting of dyes containing at least one heterosulphur atom such as 2,2.sup.1,5.sup.1,2"-terthiophene and its derivatives; thianthrene and its derivatives, and 4,6-diphenylthieno(3,4-d)-1,3-dioxol-2-one-5,5-dioxide; phenylsulfone and its derivatives; and 4,5-diphenyl-1,3-dioxol-2-one; 3,4-bis(acetoxymethyl)furan; chelidonic acid and its derivatives; and 5,7,12,14-pentacenetetrone. Resist images on a substrate are formed from the compositions.

Abstract: The present invention sets forth the incorporation of a substituted 2-phenyl-4,6-bis (trichloromethyl)-1,3,5-triazine in photoresists of lithographic printing plates for the purpose of promoting their shelf-life, room light stability, and developability. The present invention provides a photocurable composition comprising at least a photopolymerizable ethylenically unsaturated monomer having at least one terminal ethylenic group and capable of forming a polymer upon exposure to actinic radiation; and an s-triazine capable of initiating free radical polymerization of the photopolymerizable ethylenically unsaturated monomer and being represented by the following general formula [I]: ##STR1## wherein R.sub.1 is either OR.sub.4 or NR.sub.5 R.sub.6, wherein R.sub.5 and R.sub.6 may or may not be identical with each other, either R.sub.5 or R.sub.6 may represent hydrogen, and wherein R.sub.4 and at least one of R.sub.5 and R.sub.

Abstract: A liquid composition which on exposure to actinic radiation polymerizes to form a heat-curable solid film adhesive, said composition comprising (A) a heat-curable phenol-aldehyde resol resin, (B) a photopolymerizable polyurethane or polyester having, on average, more than one polymerizable acrylic group per molecule, or a mixture of said polyurethane and said polyester, (C) a photopolymerization initiator for (B) and (D) a polyvinylacetal.

Abstract: Disclosed is an epoxy resin-based composite material formed by coating or impregnating a sheet-like reinforcement with an epoxy resin composition, followed by curing the resin composition. The epoxy resin composition comprises a compound having at least one epoxy group, a compound having an active hydrogen, a silicon compound having or generating hydroxy group bonded to silicon atom, and an organometallic compound. The epoxy resin may further comprise a maleimide compound or a powdery and granular material and a short fiber. The composite material ensures the properties of the epoxy resin material in terms of the mechanical strength, corrosion resistance, heat resistance and electrical properties. Besides, the composite material exhibits excellent crack resistance and impact resistance. Further, the epoxy resin composition contained in the composite material exhibits sufficient curing characteristics and, thus, the operation for forming the composite material is facilitated.

Abstract: An ultraviolet radiation curable silica coating composition containing (a) acrylic monomers, (b) functionalized colloidal silica, (c) acrylated urethanes, (d) an ultraviolet radiation absorber, and (e) a photoinitiator. The coating composition once applied to and cured on a thermoplastic substrate provides a coating which exhibits improved flexibility and weathering. The coatings are useful for providing abrasion resistance and weatherability to thermoplastic, for example polycarbonate, substrates.

Abstract: A negative type photosensitive electrodepositing resin composition comprising (a) a polymer obtained by neutralizing a copolymer of acrylic or methacrylic acid and having an acid number of 20 to 300 with a basic organic compound, (b) a non-water-soluble monomer having two or more photopolymerizable unsaturated bonds in the molecule, (c) a non-water-soluble photoinitiator, and (d) a benzotriazole derivative having one or more carboxyl groups, is effective for giving electrodeposited films with a low voltage or low electric current in a short time, and usable for forming resist patterns with high degree of resolution.

Abstract: Curable norbornene-thiol compositions are stabilized by addition of a non-acidic Nitroso compound.

Abstract: The present invention is directed to a non-emissive, bimodal cured polymeric network which has an onset degradation temperature that is about 100.degree. C. above the onset degradation temperature of a base polymer. The novel cured polymeric network comprises the cured reaction product of the following ingredients: (a) combination of one or more liquid carrier monomers or prepolymers which combination is reactive to form a base polymer by exposure to ultraviolet (UV) radiation in the presence of a UV photosensitizer at a temperature, T.sub.uv ; and (b) between about 10 and 100 wt-% based on ingredient (a) of a combination of one or more monomers or prepolymers which combination is reactive to form a cured high temperature stable polymer by heating at a temperature, T.sub..DELTA.. Ingredient (b) is soluble or dispersible in ingredient (a) at a temperature, T.sub.s, wherein T.sub.s is equal to or lower than T.sub.uv, and T.sub.uv is at least about 50.degree. C. lower than T.sub..DELTA..

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 dental composition comprising a vinyl monomer containing at least one acidic group in the molecule thereof and an initiator capable of photopolymerizing said monomer by visible light, characterized in that said initiator consisting essentially of:(a) a photosensitizer selected from an .alpha.-diketone, a quinone and a derivative thereof, and,(b) an accelerator selected from a compound containing at least one mercapto group in the molecule thereof is provided by the present invention.

Abstract: A radiation-curing resin composition comprising (A) a resin having a carboxylic acid group and an unsaturated double bond and (B) a compound containing a cyclocarbonate group. The composition is excellent in stability and curing properties and provides a cured film excellent in water resistance, solvent resistance, chemical resistance, and heat resistance.

Abstract: Adding a dye with a visible color to an ultraviolet radiation curable composition which contains a photoinitiator which generates free radicals upon exposure to ultraviolet radiation produces a composition which changes visible color upon exposure to ultraviolet radiation. This visible color change indicates that the composition has cured. This cure indication is useful for compositions curable by ultraviolet radiation in the electronics and electrical industry.

Abstract: A printed circuit board has a resist layer made from a photo-setting resist composition containing:(A) a polyfunctional unsaturated compound which is solid at room temperature,(B) a polyfunctional unsaturated compound which is liquid at room temperature,(C) a photopolymerization initiator,(D) an epoxy resin,(E) at least one member selected from the group consisting of:(i) a curing agent for the epoxy resin and either melamine or the derivative thereof, and(ii) a compound having a 2,4-diamino-s-triazine ring and an imidazole ring in the molecule.

Abstract: Photopolymerizable compositions containing photoinitiator systems that absorb in the visible are disclosed. The photoinitiator system comprises a sensitizer which is a compound of the structure I: ##STR1## wherein R.sub.2 and R.sub.

Abstract: A Photohardenable composition consisting essentially of a free radical polymerizable compound, an electron donating coinitiator, and a benzospiropyran, wherein the benzospiropyran undergoes ring opening to form a merocyanine upon exposure to a actinic radiation or heat and exposure to a second 296 radiation causes the composition to harden.

Abstract: Compounds of the formula I ##STR1## in which at least one of the radicals R.sub.1, R.sub.2 and R.sub.3 is a substituted alkyl radical or cycloalkyl radical, or R.sub.1 and R.sub.2 together with the phosphorus atom form a monocyclic or tricyclic ring, are effective photoinitiators for the photopolymerization of ethylenically unsaturated compounds.

Abstract: A photoacid-generating photoresist composition sensitized with an aromatic, multi-ring, heterocylcic nitrogen containing sensitizer, preferably a ring extended phenothiazine derivative. The use of the sensitizer permits exposure of photoresists to near UV irradiation where such photoresists have heretofore been exposed to deep UV irradiation. The invention is especially useful for acid hardening photoresist systems.

Abstract: A process for texturing a coating via exposing a photocurable composition comprising a multifunctional urea compound, an ethylenically unsaturated compound, and an aromatic ketone photosensitizer that functions through a hydrogen abstraction mechanism when exposed to ultraviolet light.

Abstract: A dental adhesive comprising a (meth)acryloylaminoalkyl carboxylate of the formula ##STR1## in which R.sup.1 represents hydrogen or methyl;R.sup.2 represents methylene or ethylene; andR.sup.3 represents hydrogen, methyl, or ethyl;and at least one of an initiator, a non-toxic solvent, and a filler. The dental adhesive is useful to effect a strong adhesive bonding of dental materials to collagen-containing materials.

Abstract: The present invention relates to a light-sensitive composition comprising (a) a photo-crosslinkable polymer having a maleimido group at a side chain and (b) a sensitizer such as the following compounds: ##STR1## The present invention provides a light-sensitive composition having very high sensitivity; providing excellent images during only a short exposure time; and being sensitive to light of long wave length.

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: Pressure-sensitive acrylate-based adhesive copolymers comprising polymerized acrylate units and polymerized fluorochemical surfactant units and a process for preparing same. Also prepolymeric compositions comprising the monomeric components of an acrylate-based pressure-sensitive adhesive and a polymerizable fluorochemical surfactant. The prepolymeric compositions generally have surface energy lower than that of the monomeric components of the acrylate-based pressure sensitive adhesive alone. Also, the adhesive compositions better maintain adhesive properties when aged when compared to corresponding adhesive compositions involving non-polymerizable fluorochemical surfactants.

Abstract: In-situ development of an ultraviolet absorber is provided by a compound such as a hydroxy-phenyl-triazole containing a group which protects the absorber during actinically activated polymerization by light at first frequency. After polymerization the protective group is removed by actinic reaction at a second frequency lower than the first frequency. The protective group is formed by replacing the hydrogen of the hydroxyl group with an acyl group containing 1 to 3 carbon atoms or an acryloxy group of the formula: ##STR1## where R.sup.1 is either an alkyl containing 1 to 6 carbon atoms or --CH.dbd.CH.sub.2.

Abstract: A polymerizable composition and a method are disclosed. The composition includes a photopolymerizable monomer and a photoinitiator system for the monomer. The system, in one embodiment, is one wherein a ray of activating radiation which enters a body of the composition through a surface thereof activates the photoinitiator system and causes polymerization at each of a succession of points, the first such point being immediately adjacent the surface and subsequent points being successively farther from the surface in the direction of travel of the ray of activating radiation, the distance from the surface to the point of the succession farthest therefrom varying as a function of at least one of(a) the intensity of the activating radiation and(b) the time during which the activating radiation enters the body through the surface.

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: These photopolymerizable laminating materials consist of at least one film-forming polymer as a binder, at least one organic compound which is compatible with the binder, has at least two double bonds capable of addition polymerization and may be partially replaced by an organic compound having only one double bond capable of addition polymerization, a photoinitiator or photoinitiator system and an adhesion promoter, with or without conventional additives and assistants, the adhesion promoter used being a tricyclic heteroaromatic compound which is soluble in aqueous alkaline solutions.The said laminating materials are suitable for the production of printed circuits.

Abstract: Combinations of selected photosensitizers produce unexpected increases in the both the photospeed of, and the resolution obtainable from, photopolymerizable compositions. The combinations contain one photosensitizer, known as the sensitizer, and a second photosensitizer, known as the co-sensitizer. The co-sensitizer has an absorbance maximum at a longer wavelength than the sensitizer and is generally present a much lower concentration than the sensitizer.

Abstract: In a photosensitive recording element which contains at least one photopolymerizable recording layer (B) consisting ofb.sub.1) at least one partially of virtually completely hydrolyzed poly(vinyl alkanecarboxylate) and/or at least one partially or virtually completely hydrolyzed vinyl alkanecarboxylate/alkylene oxide graft copolymer as a binder,b.sub.2) at least one photopolymerization initiator,b.sub.3) at least one photopolymerizable olefinically unsaturated compound (monomer) which is compatible with the binder (b.sub.1), and/or photopolymerizable olefinically unsaturated radicals which are bonded as side radicals and/or terminal radicals to the binder (b.sub.1), andb.sub.4) at least two assistants, at least one of the said assistants (b.sub.4) has been selected from the group consisting ofb.sub.41) the isoalloxazines and the alloxazines, and at least one of the other assistants has been selected from the group consisting ofb.sub.

Abstract: Rapid changes in absorption are made within the volume of a photosensitive transparent member that absorbs incident radiation to prevent the photocopy of a document, the original transparency being restored after discontinuance of the incident radiation.

Abstract: The invention relates 6-acyl-(6H)-dibenz[c,e][1,2]oxaphosphorine-6-oxides of the formula ##STR1## wherein each of R.sup.1, R.sup.2 and R.sup.3 may be present one or more times and R.sup.1, R.sup.2 and R.sup.3 represent halogen having an atomic number of from 9 to 35, alkyl or alkoxy each having from 1 to 6 carbon atoms and wherein Ar represents an aromatic hydrocarbon group having from 6 to 10 carbon atoms.The invention further relates to a process for the preparation of the afore-mentioned compounds and polymerizable compositions containing them as an essential ingredient as a photo-initiator. Finally the invention relates to 6-alkoxy-(6H)-dibenz[c,e][1,2]oxaphosphorin of the formula II ##STR2## wherein each of R.sup.1 and R.sup.2 may be present once or more times and R.sup.1 and R.sup.2 represent halogen having an atomic number of from 9 to 35, alkyl or alkoxy each having from 1 to 6 carbom atoms, at least one R.sup.1 being, however, halogen, and wherein R.sup.

Abstract: An energy polymerizable composition and process therefore, comprising a cationically polymerizable material and a catalytically effective amount of an ionic salt of an organometallic complex cation as polymerization initiator, said ionic salt of an organometallic complex cation being capable of adding an intermediate strength nucleophile or upon photolysis capable of liberating at least one coordination site, said metal in said organometallic complex cation being selected from elements of Periodic Groups IVB, VB, VIB, VIIB, and VIIIB are disclosed. Certain of the organometallic metallic polymerization initiators are novel cationic salts.

Abstract: A light-sensitive composition comprises a photo-crosslinkable polymer having a photo-dimerizable unsaturated bond and a sensitizer represented by the following general formula (I): ##STR1## wherein R.sub.1 and R.sub.2 each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group or a substituted or unsubstituted allyl group, provided that R.sub.1 and R.sub.2 may form a ring together with the carbon atoms to which they are attached; n represents 0, 1 or 2; and G.sub.1 and G.sub.2 each independently represents a hydrogen atom, a cyano group, a substituted or unsubstituted alkoxycarbonyl group, a substituted or unsubstituted aryloxycarbonyl group, a substituted or unsubstituted acyl group, a substituted or unsubstituted arylcarbonyl group, an alkylthio group, an arylthio group, an alkylsulfonyl group, an arylsulfonyl group or a fluoroalkylsulfonyl group, provided that G.sub.1 and G.sub.

Abstract: A photopolymerizable composition that contains a polymeric binder, a polymerizable compound and photoinitiator combination comprising an N-heterocyclic compound and a halogen compound corresponding to one of the folowing formulas I and II ##STR1## in which X.sup.1 stands for chlorine or bromine,X.sup.2 and X.sup.3 are identical or different and denote X.sup.1, hydrogen or alkyl groups,Y and Z are identical or different and denote X.sup.1, hydrogen, CN or (A).sub.n --(B).sub.n --D,A is a phenylene group,n is 0 or 1,B is CO or SO.sub.2,D is R, OR, NHR, NH.sub.2, NR.sub.2 or CX.sup.1 X.sup.2 X.sup.3,R is an alkyl, cycloalkyl, aryl or heteroyl radical,W is a five or six-membered heterocyclic ring having from 1 to 3 heteroatoms, which optionally carries substituents and optionally a fused aromatic ring, andm is 1 or 2,is distinguished by an improved light sensitivity.

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 photopolymerizable composition comprising (a) an addition polymerizable compound having a boiling point of 100.degree. C. or high under an atmospheric pressure, (b) a photoinitiator, and (c) a benzene derivative can provide a cured film having high strength suitable for producing, e.g. printed circuit boards.

Abstract: Disclosed is a photocurable composition comprising (a) a radical-polymerizable monomer, (b) an .alpha.-ketocarbonyl compound and (c) a derivative of mercaptobenzimidazole, mercaptobenzothiazole or mercaptobenzoxazole or an aromatic amine nucleus-substituted with an electron-attractive group. This composition has a high photocuring speed at a temperature close to normal temperature and gives a cured product excellent in various physical properties. This composition is valuable as a dental adhesive or resin.