Abstract: The present invention relates to a method of forming a crosslinked polymer gel, to a polymer gel produced by such method and to uses of such polymer gel.

Abstract: A curable composition containing a lake dye having an absorption maximum in the wavelength region of from 700 nm to 1100 nm and a thermosetting compound and/or a photo-setting compound; a solid imaging device installing therein a filter prepared using the curable composition; and a lake dye represented by the following formula (V): wherein L1 represents a methine chain composed of odd number(s) of methine group(s); A1 and A2 are each independently represents an alkyl group having a sulfo group; Y represents a cation necessary to balance a charge and selected from the group consisting of alkali earth metal ions (Mg2+, Ca2+, Ba2+, Sr2+), transition metal ions (Ag+, Fe+, Co2+, Ni2+, Cu2+, Zn2+) and (Al3+).

Abstract: A photo curable ink composition set, comprising: an ink composition A that includes at least a color material, a polymerizable compound, and a radical polymerization photoinitiator; and an ink composition B that includes at least a radical polymerizable compound and does not include the color material and the radical polymerization photoinitiator, wherein the ink composition A and/or B includes a sensitizer.

Abstract: The invention relates to a coating formulation for preparing a hydrophilic coating, wherein the hydrophilic coating formulation comprises a supporting monomer and/or polymer comprising at least 2 reactive moieties capable of undergoing polymerization reactions, a polyelectrolyte, a Norrish Type I photoinitiator, and a Norrish Type II photoinitiator.

Abstract: Compounds of the Formula (I) and (II) wherein M1, M2 and M3 independently of one another are no bond, a direct bond, CO, O, S, SO, SO2 or NR14; provided that at least one of M1, M2 or M3 is a direct bond, CO, O, S, SO, SO2 or NR14; M4 is a direct bond, CR?3R?4, CS, O, S, SO, or SO2; Y is S or NR18; R1 for example is hydrogen, C3-C8cycloalkyl, phenyl or naphthyl, both of which are optionally substituted; R2 for example is C1-C20alkyl; R?2 has one of the meanings given for R2; R3 and R4 are for example hydrogen, halogen, C1-C20alkyl; R?3, R?4, R?3 and R?4 independently of one another have one of the meanings given for R3 and R4; and R5 is for example hydrogen, halogen, C1-C20alkyl; provided that in the compounds of the Formula (I) at least two oxime ester groups are present; exhibit an unexpectedly good performance in photopolymerization reactions.

Abstract: The invention provides an ink composition including a sensitizer represented by the following Formula (I), a photopolymerization initiator, and a polymerizable compound having an ethylenic unsaturated bond. In the Formula (I), R1, R6 and R8 each independently represent a hydrogen atom, a hydroxyl group, a halogen atom, a linear or branched alkyl group which may be substituted, or an alkoxy group which may be substituted. R2, R4, R5 and R7 each independently represent a hydrogen atom, a halogen atom, or a cyano group. R3 represents a hydrogen atom, a linear or branched alkyl group which may be substituted, or a cycloalkyl group which may be substituted.

Abstract: An oxime ester compound represented below is useful as a photopolymerization initiator. A photopolymerization initiator including this as an active constituent has high sensitivity and causes no concern about coloration or contamination. (X represents a halogen atom or alkyl group. R1, R2, and R3 each independently represent R, OR, COR, SR, CONRR?, or CN, wherein R and R? each represent an alkyl group, an aryl group, an aralkyl group, or a heterocyclic group; these groups may be substituted with (a) halogen atom(s) and/or (a) heterocyclic group(s); the alkylene moiety in the alkyl or aralkyl group may be interrupted by (an) unsaturated bond(s), (an) ether bond(s), (a) thioether bond(s), or (an) ester bond(s); and R and R? may form a ring. Y1 represents an oxygen, sulfur, or selenium atom; A represents a heterocyclic group; m represents an integer 0-4; p represents an integer 0-5; and q represents 0 or 1.

Abstract: An ink-jet ink composition containing the following components of (a), (b), and (c), and having a viscosity at 25° C. in the range of from 5 mPa·s to 100 mPa·s, (a) a polymerizable compound, (b) a photopolymerization initiator, and (c) a sensitizer represented by the following formula (i): in the Formula (i), X represents O, S or NR; n represents an integer of 0 or 1; R represents a hydrogen atom, an alkyl group or an acyl group; each of R1, R2, R3, R4, R5, R6, R7 and R8 independently represents a hydrogen atom or a monovalent substituent, provided that any neighboring two of R1, R2, R3 and R4 may be bonded to each other to form a ring, and R5 and R7 or R8, or R6 and R7 or R8, may be bonded to each other to form an aliphatic ring but do not form an aromatic ring.

Abstract: Compounds of the formulae (I), (II), (III) and (IV), wherein Ch1 is e.g. the formula (V) or (VI); Ch2 is the formula (VII) or (VIII); Het1 is for example furyl, thienyl, pyrrolyl, pyridyl, benzothienyl, quinolyl or bithienyl; each of which is optionally substituted; Het2 and Het2? e.g. are furylene, thienylene, pyrrolylene, benzothienylene, quinolylene, furylenecarbonyl, thienylenecarbonyl, benzothienylenecarbonyl or bithienylenecarbonyl; each of which is optionally substituted; A1, and Ar1? i.a. are phenyl, naphthyl, benzoyl or naphthoyl, each of which is optionally substituted; Ar2 is for example phenylene, optionally substituted; M i.a. is C1-C20alkylene; R1 is for example C1-C12alkyl or phenyl; R2 and R2? for example are hydrogen or C1-C20 alkyl; exhibit an unexpectedly good performance in photopolymerization reactions.

Abstract: An optical film comprising a support and a layer containing a cured product of a composition which contains a fluorinated photopolymerization initiator and an ionizing radiation-curing compound.

Abstract: Lithographic printing plate precursor comprising (a) a lithographic substrate with a hydrophilic surface and (b) a radiation-sensitive coating on the hydrophilic surface comprising (i) one or more types of monomers and/or oligomers and/or polymers, each comprising at least one ethylenically unsaturated group accessible to a free radical polymerization, (ii) at least one sensitizer, and at least one coinitiator capable of forming free radicals together with the sensitizer (ii); characterized in that the at least one sensitizer is an oligomeric or polymeric compound comprising the following structural unit (Formula (I)), wherein ?1 is an aromatic or heteroaromatic unit or a combination of the two so that a conjugated n-system is present between the two groups Z in structure (I), each Z independently represents a heteroatom, each R1 and R2 is independently selected from a halogen atom, an alkyl, aryl, alkylaryl or aralkyl group, a group —NR3R4 and a group —OR5, each R3, R4 and R5 is independently selected from a

Abstract: A photopolymerization process for producing pigmented and non-pigmented articles comprises irradiating with electromagnetic radiation in the range from 190 to 600 nm, or with electron beam or with X-rays a photosensitive composition which can be developed by alkali solution which composition comprises (A) a polymer containing at least one carboxylic acid group in the molecule and having a molecular weight of 200,000 or less, (B) selected ?-aminoalkylphenone compounds as photoinitiators and (C) an ester of a polyol, wherein the polyol is partially or fully esterified with an ethylenically unsaturated carboxylic acid a monomeric, oligomeric or polymeric compound having at least one olefinic double bond.

Abstract: A composition that is photopolymerizable upon absorption of light in the wavelength range from 300 to 450 nm, the composition comprising a binder, a polymerizable compound, a sensitizer and a photoinitiator, characterized in that the sensitizer is an optical brightening agent having a solubility in methyl ethyl ketone of at least 15 g/kg measured at 20° C., allows to produce printing plates without pinhole defects, even if the printing plate precursor is stored before exposure and processing.

Abstract: A photocurable coating composition is provided that includes (A) a compound represented by Formula (i) below, (B) a photopolymerization initiator, and (C) a compound having an ethylenically unsaturated bond. (In Formula (I), X denotes O, S, or NR, n denotes an integer of 0 to 4, R denotes a hydrogen atom, an alkyl group, or an acyl group, R1 to R8 independently denote a hydrogen atom or a monovalent substituent, and R1 to R4 may form a ring in which two thereof that are adjacent are bonded to each other.

Abstract: Polymerizable compositions and methods are provided that include an ethylenically unsaturated compound and an arylsulfinate salt. The polymerizable compositions are useful as hardenable dental compositions.

Abstract: Compounds of formula (I) where: {R1 is methyl, ethyl, cycloalkyl or optionally substituted aryl; Z is arylene or a group of formula —(CHR4)n-, where R4 is hydrogen, hydroxy or alkyl, and n is a number from 0 to 6; Y is carbonyl or a —CH2— group; Q is a residue of a mono- or poly-hydroxyl compound having from I to 6 hydroxy groups; and x is a number from I to 6; and esters thereof} are useful as sensitizers for use in radiationcurable compositions.

Abstract: A high-solid UV-curable coating composition of the present invention, comprising a low viscosity multifunctional acrylate oligomer, a UV-curable monomer, 10% by weight or less of an organic solvent and a photoinitiator has good workability and environmental characteristics and provides a coating film having improved properties.

Abstract: The invention relates to a Radiation Curable Secondary Coating composition for use on an Optical Fiber. The Radiation Curable Secondary Coating composition is a urethane-free Alpha Oligomer prepared by reaction of the following: (a) an acrylate compound selected from an alcohol-containing acrylate or alcohol-containing methacrylate compound, (b) an anhydride compound, (c) an epoxy-containing compound, (d) optionally an extender compound, and (e) optionally a catalyst. The invention also relates to a coated wire and to a coated optical fiber.

Abstract: Photosensitive compositions which can be developed by alkali solution, comprise (A) a polymer containing at least one carboxylic acid group in the molecule and having a molecular weight of 200,000 or less, (B) selected ?-aminoalkylphenone compounds as photoinitiators and (C) an ester of a polyol, wherein the polyol is partially or fully esterified with an ethylenically unsaturated carboxylic acid a monomeric, oligomeric or polymeric compound having at least one olefinic double bond.

Abstract: An ink composition of the present invention is disclosed, which contains (i) a sensitizing dye represented by the following Formula (I); (ii) at least one polymerization initiator selected from the group consisting of ?-aminoketones and acyl phosphine oxides; and (iii) an ethylenically unsaturated bond-containing polymerizable compound. In Formula (I), X represents O, S or NR; n represents an integer of 0 or 1; R represents a hydrogen atom, an alkyl group or an acyl group; R1 to R8 each independently represent a hydrogen atom or a monovalent substituent; R1 and R2, R2 and R3, and R3 and R4 may be connected to each other to form a ring; and R5 or R6 may be connected to R7 or R8 to form an aliphatic ring but not to form an aromatic ring.

Abstract: Provided is an alkali-soluble maleimide-based copolymer which comprises, as essential constituents, 5 to 50% by mass of a maleimide monomer unit which is at least one unit selected from the group consisting of a N-cyclohexylmaleimide monomer unit, a N-benzylmaleimide monomer unit and a substituted N-benzylmaleimide monomer unit, 8 to 30% by mass of the (meth)acrylic acid monomer unit and 30 to 87% by mass of a (meth)acrylic acid ester monomer unit and which satisfies the condition represented by the formula: 0.4×X?Y?0.5×X+10 where X is the content, in % by mass, of the N-cyclohexylmaleimide monomer unit, the N-benzylmaleimide monomer unit and the substituted N-benzylmaleimide monomer unit and Y is the content, in % by mass, of the (meth)acrylic acid monomer unit. Also provided are a color filter and a liquid crystal display which are formed by using the ionizing radiation-curable resin composition.

Abstract: A cationically curable composition for dental use containing a cationic polymerization initiator (I) and cationically polymerizable monomers (II), the cationically polymerizable monomers (II) containing an oxetane compound and an epoxy compound or an alkenyl ether compound at a ratio of amounts that satisfy the conditions expressed by the following formula, (a×A):(b×B)=91:9 to 45:55 wherein A is a mol number of the oxetane compound, “a” is an average number of the oxetane functional group contained in one molecule of the oxetane compound, B is a mol number of the epoxy compound or the alkenyl ether compound, and “b” is an average number of the epoxy functional group contained in one molecule of the epoxy compound or an average number of the alkenyl ether functional group contained in one molecule of the alkenyl ether compound.

Abstract: A process for producing intraocular lenses (IOLs) capable of absorbing blue light and ultraviolet light using photo curing. Intraocular lenses so produced block blue light and ultraviolet light from reaching the retina of an eye implanted with the IOL. By blocking blue light and ultraviolet light from reaching the retina, the IOL thereby prevents potential damage to the retina.

Abstract: The invention provides compounds which can generate amine by irradiation with light and are excellent both in photodecomposability and in reactivity and compatibility with amine-curable compounds, and photo-setting compositions containing the compounds. The compounds are carbamoyloxyimino compounds represented by the structural formula (I); and the compositions each comprise one or more of the carbamoyloxyimino compounds and an amine-curable compound. In the formula (I), R1 is an n-valent organic group; R2 and R3 are each hydrogen or an aromatic or aliphatic group; and n is an integer of 1 or above.

Abstract: Disclosed are photo or electron beam polymerizable compositions, and preparation thereof and devices containing them. The composition contains completely or substantially completely hydrogenated hydrocarbon-based material completely free or substantially free of carbon-carbon double and triple bonds containing photo or electron beam curable terminal or pendant groups, low-outgassing photoinitiators, an optional viscosity adjustment component and an optional filler. The composition is visible light, UV or electron beam curable. It cures into a low-modulus, low outgassing polymer material. The composition can be used as an adhesive, sealant or lens potting material. It is ideal for use in lithographic tools involving deep or vacuum ultraviolet radiations, in particular, as lens potting materials for 157 nm lithographic tools.

Abstract: A photosensitive composition comprising, (A) an oligomer or polymer containing at least one carboxylic acid group in the molecule and having a molecular weight of 200?000 or less; (B) at least one photoinitiator compound of formula I ?wherein R1 is linear or branched C1–C12alkyl; R2 is linear or branched C1–C4alkyl; R3 and R4 independently of one another are linear or branched C1–C8alkyl; and (C) a monomeric, oligomeric or polymeric compound having at least one olefinic double bond, is especially suitable for preparting photoresists, in particular color filters.

Abstract: The invention relates to a biocompatible, low-viscous, radiation curable formulation, particularly for use in stereolithography, for use in medical technology, in particular, for producing earpieces, containing: a) 55-95% by weight of a monomeric or oligomeric dimethacrylate based on bisphenol A or bisphenol F; b) 0-20% by weight of a urethane methacrylate having a functionality of n<4 and a viscosity<15 Pa s; c) 2-15% by weight of a monomeric aliphatic or cycloaliphatic dimethacrylate having a viscosity<5 Pa s; d) 0-15% by weight of a monofunctional methacrylate having a viscosity<3 Pa s; e) 0.5-6% by weight of a photoinitiator or a combination of a number of photoinitiators whose absorption is located within the wavelength range of the laser beam used; f) 0.

Abstract: An oxygen scavenger composition includes an organic oxygen scavenger, a transition metal catalyst, and a blend of at least two photoinitiators selected from 1,3,5-tris(4-benzoylphenyl)benzene, thioxanthone derivative, acyl phenylphosphineoxide derivative, and diphenyl sulfide derivative. A film includes at least one layer including an organic oxygen scavenger, a transition metal catalyst, and a blend of at least two photoinitiators selected from 1,3,5-tris(4-benzoylphenyl)benzene, thioxanthone derivative, acyl phenylphosphineoxide derivative, and diphenyl sulfide derivative.

Abstract: A two-photon absorbing polymerizable composition contains at least a two-photon absorbing compound, a polymerization initiator and a polymerizable compound, the composition being photopolymerizable upon non-resonant two-photon absorption, wherein the two-photon absorbing compound is a methine dye containing a compound represented by the formula (1): wherein R1 to R5 each represents a hydrogen atom or a substituent and some of R1 to R4 may combine with each other to form a ring; n and m each independently represents an integer of 0 to 4, provided that n and m are not 0 at the same time; X1 and X2 each represents an aryl group, a heterocyclic group or a group represented by formula (2); R6 represents a hydrogen atom, an alkyl group, an alkenyl group, an aryl group or a heterocyclic group, and Z1 represents an atomic group for forming a 5- or 6-membered ring.

Abstract: Crosslinkable resin compositions that are cured easily by irradiation with active energy beams and particularly cured quickly with ultraviolet ray are provided, which comprises a polymer containing a maleimido group and an ethylenically unsaturated group. The composition may be an aqueous composition. They provide cured films which are excellent in durability, free from coloring and odors, and also excellent in abrasion resistance, adhesion to substrates, surface smoothness, and chemical resistance.

Abstract: A photopolymerization initiator comprising (A) an ?-diketone compound such as camphorquinone, (B1) an aliphatic amine compound such as triethanolamine or N-methyldiethanolamine, (B2) an aromatic amine compound such as ethyl p-dimethylaminobenzoate or N,N-dimethyl p-toluidine, and (C) a triazine compound substituted with a trihalomethyl group, such as 2,4,6-tris(trichloromethyl)-s-triazine or 2-phenyl-4,6-bis(trichloromethyl)-s-triazine. The photopolymerization initiator remains stable against the environmental light such as the indoor illumination light from a fluorescent lamp or the dental light illuminating the interior of the oral cavity, is excellently handled, is quickly cured by the irradiation with an intense light emitted from a light irradiator for polymerization, provides a cured body having excellent properties, can be stably preserved even at high temperatures, and is very useful as a dental composite resin.

Abstract: Compositions are provided that include an electron donor and a sensitizing compound. More specifically, the electron donor is an arylsulfinate salt. Methods of polymerization are also provided that can be used to prepare polymeric material from a photopolymerizable composition that includes ethylenically unsaturated monomers and a photoinitiator system. The photoinitiator system includes an electron donor and a sensitizing compound.

Abstract: A light-curable resin composition includes an acrylate oligomer, an acrylate monomer having 4 or less functional groups, a photopolymerization initiator, a hardness enhancing agent represented by the formula(1), m-terphenyl represented by the formula(2) and a colloidal antistatic agent. The light-curable resin composition has a high antistatic property and a light transmittance, as well as a high hardness and a low shrinkage rate.

Abstract: An eyeglass lens forming composition containing light absorbing compounds which may undergo light initiated polymerization is provided. Typically, lens forming compositions that absorb light do not permit enough activating radiation to penetrate into the depths of the lens cavity to adequately initiate polymerization of the lens forming composition. An embodiment of the invention provides a system and method for curing such a lens forming composition to form a lens that does not transmit ultraviolet light. Activating light is used having a wavelength greater than the wavelengths of light which the light absorbing compounds absorb. The power of the formed lenses may be controlled by varying the lens forming conditions. Additionally, the lens forming process may be controlled using a microprocessor based control system.

Abstract: The present invention discloses an ultraviolet light curable paint composition and method for applying and making such a composition to a substrate. Suitable substrates include glass, metals, and various plastics such as polycarbonates. The disclosed composition does not contain any significant amount of volatile organic solvents that do not become incorporated in the coating or are released to ambient after curing.

Abstract: A photosensitive composition comprising (i) a sensitizing dye represented by the following formula (I), (II) or (III) defined in the specification, (ii) a titanocene compound and (iii) a compound of undergoing a reaction with at least one of a radical and an acid to change at least one of its physical and chemical properties and maintaining the changed physical or chemical property, and a lithographic printing plate having a photosensitive layer comprising the photosensitive composition.

Abstract: Aliphatic maleimides and methods using the same are disclosed. Polymerization of compositions which include the compounds of the invention may be activated by irradiating the composition with radiation.

Abstract: A light-curable resin composition includes an acrylate oligomer, an acrylate monomer having 4 or less functional groups, a photopolymerization initiator, a hardness enhancing agent represented by the formula(1), m-terphenyl represented by the formula(2) and a colloidal antistatic agent. The light-curable resin composition has a high antistatic property and a light transmittance, as well as a high hardness and a low shrinkage rate.

Abstract: The preset invention relates to a photosensitive composition, and provides a triazine-based compound comprising new functionalized alkylthio groups of which long term storage characteristics at room temperature as well as photochemical activity as a photopolymerization initiator are superior.

Abstract: A multiphoton-activatable, photoreactive composition comprises: (a) at least one reactive species that is capable of undergoing an acid- or radical-initiated chemical reaction; (b) a photochemically-effective amount of a multiphoton photosensitizer comprising at least one multiphoton up-converting inorganic phosphor; and (c) a photochemically-effective amount of a one-photon photoinitiator system that is capable of being photosensitized by the multiphoton photosensitizer.

Abstract: Provided is a photopolymerizable composition which has a high sensitivity to not only ultraviolet light but also to visible to infrared light.

Abstract: A radiation-curable composition that includes a cyanoacrylate component or a cyanoacrylate-containing formulation, a photoinitiated radical generating component, and a photoinitiator component is provided.

Abstract: Disclosed are thermally-stable, red, anthraquinone colorants which contain one or more ethylenically-unsaturated, photopolymerizable radicals and which may be copolymerized with ethylenically-unsaturated monomers to produce colored compositions such as colored acrylic polymers, colored polystyrenes, and similar colored polymeric materials derived from other ethylenically-unsaturated monomers. The compounds possess good stability to ultraviolet light, good solubility in vinyl monomers, good color strength and thermal stability. Also disclosed are acrylic polymeric materials, i.e., polymers derived from acrylic acid esters, methacrylic acid esters and/or other copolymerizable vinyl compounds, having copolymerized therein one or more of the colorant compounds of the present invention.

Abstract: The present invention relates to a paste composition, including a bonding agent charged with a metallic powder, to be used in a prototyping procedure, a procedure for obtaining metallic products from said composition, and a metallic product obtained from said procedure.

Abstract: The present invention relates to photocatalytic compositions effective to degrade soils deposited on a surface, to reduce the accumulation of soils on a surface, and to act as an antimicrobial agent. The invention also describes methods employing said compositions, and uses thereof.

Abstract: The present invention provides an IR-sensitive composition, which includes: a polymeric binder; and a free radical polymerizable system consisting of: at least one component selected from unsaturated free radical polymerizable monomers, oligomers which are free radical polymerizable and polymers containing C═C bonds in the backbone and/or in the side chain groups; and an initiator system, which includes: (a) at least one compound capable of absorbing IR radiation; (b) at least one compound capable of producing radicals; and (c) at least one carboxylic co-initiator, provided that the total acid number of the polymeric binder is 70 mg KOH/g or less. The present invention further provides a printing plate precursor, a process for preparing the printing plate and a method of producing an image.

Abstract: Photoactivatable coating composition comprising at least one photoinitiator and a base-catalysed polymerisable or curable organic material comprising at least one polyisocyanate and at least one compound containing isocyanate reactive groups, wherein the isocyanate reactive groups comprise at least one thiol group and the photoinitiator is a photolatent base. Preference is given to a coating composition wherein the photolatent base is selected from the group of N-substituted 4-(ortho-nitrophenyl) dihydropyridine, a quaternary organo-boron photoinitiator, and an &agr;-amino acetophenone. The composition additionally may comprise an organic acid, a metal complex and/or a metal salt as a cocatalyst and/or a sensitiser selected from the group of thioxanthones, oxazines, rhodamines, and preferably from the group of benzo-phenone and derivatives thereof.

Abstract: A photopolymerizable composition sensitive to near infrared radiation, comprises: (i) a photopolymerizable monomer or oligomer, or a mixture thereof, capable of forming a polymer having predetermined optical properties; (ii) a photoinitiator sensitive to near infrared radiation, the photoinitiator comprising a dye sensitizer and an initiator, wherein the dye sensitizer is a cyanine dye having a perchlorate anion and the initiator is an electron donor; and (iii) a filler having optical properties selected to contrast with the optical properties of the polymer. The composition of the invention is particularly useful for producing holographic polymer dispersed liquid crystal (H-PDLC) materials and reversible dye doped polymer (RDDP) materials having improved switching characteristics.

Abstract: New photocationic photoinitiator combinations are described that consist of 2,4,6-triarylpyrylium salts with non-nucleophilic anions and electron donors, that are able rapidly to crosslink unpigmented as well as pigmented mixtures based on cycloaliphatic epoxides to form colourless layers such as lacquers and printing inks without generating interfering and toxic emissions.

Abstract: A photocurable composition comprising (A) an &agr;-cyanoacrylate and (B) a metallocene compound comprising a transition metal of Group VIII of the periodic table and aromatic electron system ligands selected from &pgr;-arenes, indenyl, &eegr;-cyclopentadienyl. The photocurable composition may further comprise (C) a cleavage-type photoinitiator. The photocurability of the photocurable composition can be greatly improved by incorporating a cleavage type photoinitiator into the composition. Even when the composition contains a radical-polymerizable compound such as an acrylic compound, it can be rapidly cured due to the cleavage type photoinitiator contained therein. In the case where the cleavage-type photoinitiator used is a peroxide, heating can also be used to cure the composition. In the case where the cleavage type photoinitiator used is an azo compound, the composition can be foamed by regulating the addition amount of the photoinitiator or the quantity of light with which the composition is irradiated.