A photoinitiated polymerizable composition for 3D printing, the polymerizable composition comprising a nanogel component that comprises nanogel particles, wherein the nanogel particles comprise a copolymer with polymerizable reactive groups suitable for reacting with each other or a reactive diluent monomer, a reactive oligomer, a resin, or a combination thereof that is present in the polymerizable composition upon photoinitiation, wherein the nanogel component has a glass transition temperature that is in a range of about −50 C and about 20 C and an average molecular weight that is in a range of about 10 kg/mol and about 100 kg/mol, and wherein the nanoparticles have an average hydrodynamic radius that is in a range of 1 nm to about 5 nm.

An adhesive composition of the present application includes the following components (A) to (C): (A) a radically polymerizable compound; (B) a polymer having a weight-average molecular weight of 35,000 to 110,000 and having a repeat unit derived from a polymerizable compound of formula (I) (wherein X.sup.1 and X.sup.2 each independently represent a C7 to C20 alkyl group or a C7 to C20 alkoxy group, n represents 0 or 1, Z.sup.1 and Z.sup.2 each independently represent a single bond or a Cl to C3 alkylene group, each R independently represents an organic group or a halogeno group, m1 and m2 each independently represent any integer of 0 to 4, and Y represents a polymerizable functional group); and (C) a radical polymerization initiator.

##STR00001##

There is provided a maintenance liquid, which is used in maintenance of a device equipped with a discharge head for discharging an ultraviolet ray curable-type composition containing the acyl phosphine oxide-based photopolymerization initiator toward an attachment object, including a polymerizable compound in which a saturation solubility of an acyl phosphine oxide-based photopolymerization initiator at 20° C. is equal to or greater than 5.0% by mass.

There is provided a maintenance liquid, which is used in maintenance of a device equipped with a discharge head for discharging an ultraviolet ray curable-type composition containing the acyl phosphine oxide-based photopolymerization initiator toward an attachment object, including a polymerizable compound in which a saturation solubility of an acyl phosphine oxide-based photopolymerization initiator at 20° C. is equal to or greater than 5.0% by mass.

A photocurable liquid silicone composition, that has low viscosity that facilitates injection into a small gap, cures quickly by irradiating with a high energy beam (such as ultraviolet light or the like), has a refractive index after curing that is high not only in a visible region but also in an infrared region, and is particularly useful as a material for a device using an infrared LED light source, is provided. The photocurable liquid silicone composition comprises: (A) an organosilane or low molecular weight organosiloxane with one to five silicon atoms and in one molecule, at least two alkenyl groups and at least two monovalent functional groups selected from aromatic groups and aralkyl groups, (C) in one molecule, a compound having at least two mercapto groups, and (D) a photoradical initiator. The refractive index of the entire liquid composition, prior to curing, is 1.48 or higher.

A photocurable liquid silicone composition, that has low viscosity that facilitates injection into a small gap, cures quickly by irradiating with a high energy beam (such as ultraviolet light or the like), has a refractive index after curing that is high not only in a visible region but also in an infrared region, and is particularly useful as a material for a device using an infrared LED light source, is provided. The photocurable liquid silicone composition comprises: (A) an organosilane or low molecular weight organosiloxane with one to five silicon atoms and in one molecule, at least two alkenyl groups and at least two monovalent functional groups selected from aromatic groups and aralkyl groups, (C) in one molecule, a compound having at least two mercapto groups, and (D) a photoradical initiator. The refractive index of the entire liquid composition, prior to curing, is 1.48 or higher.

A photocurable composition includes a photopolymerizable component and a photopolymerization initiator. When a test piece with a length of 39 mm, a width of 8 mm, and a thickness of 4 mm, is produced by photofabrication under conditions in which the photocurable composition is irradiated with visible light having a wavelength of 405 nm at an irradiation dose of 12 mJ/cm.sup.2 to form a cured layer with a thickness of 100 .Math.m, the cured layer is stacked in a thickness direction thereof to form a rectangular fabrication product with a length of 39 mm, a width of 8 mm, and a thickness of 4 mm, and the fabrication product is irradiated with ultraviolet rays having a wavelength of 365 nm at an irradiation dose of 10 J/cm.sup.2 to produce the test piece, a total fracture work of the test piece measured in compliance with ISO20795-1:2008 is 1100 J/m.sup.2 or more.

A photocurable composition includes a photopolymerizable component and a photopolymerization initiator. When a test piece with a length of 39 mm, a width of 8 mm, and a thickness of 4 mm, is produced by photofabrication under conditions in which the photocurable composition is irradiated with visible light having a wavelength of 405 nm at an irradiation dose of 12 mJ/cm.sup.2 to form a cured layer with a thickness of 100 .Math.m, the cured layer is stacked in a thickness direction thereof to form a rectangular fabrication product with a length of 39 mm, a width of 8 mm, and a thickness of 4 mm, and the fabrication product is irradiated with ultraviolet rays having a wavelength of 365 nm at an irradiation dose of 10 J/cm.sup.2 to produce the test piece, a total fracture work of the test piece measured in compliance with ISO20795-1:2008 is 1100 J/m.sup.2 or more.

A radiation-curing ink jet ink composition includes a urethane (meth)acrylate including one (meth)acryloyl group, the amount of the urethane (meth)acrylate being 5.0% by mass or more and 30.0% by mass or less of the total amount of the ink composition, and a (meth)acrylate including an aromatic ring and one (meth)acryloyl group, the amount of the (meth)acrylate being 4.0% by mass or more and 50.0% by mass or less of the total amount of the ink composition.

A radiation-curing ink jet ink composition includes a urethane (meth)acrylate including one (meth)acryloyl group, the amount of the urethane (meth)acrylate being 5.0% by mass or more and 30.0% by mass or less of the total amount of the ink composition, and a (meth)acrylate including an aromatic ring and one (meth)acryloyl group, the amount of the (meth)acrylate being 4.0% by mass or more and 50.0% by mass or less of the total amount of the ink composition.