Abstract: Hollow silica-based particles having cavities inside the outer shell having a low refractive index. The method of producing the silica-based particles comprises the following steps (a) and (b): (a) a step in which, when an aqueous silicate solution and/or an acidic silicic acid solution and an aqueous solution of an alkali-soluble inorganic compound are simultaneously added in an alkali aqueous solution to prepare a dispersion liquid of composite oxide particles, an electrolytic salt is added at the molar ratio of a mole number of the electrolytic salt (ME) versus that of SiO2 (MS) [(ME)/(MS)] in the range from 0.1 to 10, and (b) a step of furthermore adding an electrolytic salt, if necessary, to the dispersion liquid of composite oxide particles and then removing at least a portion of elements constituting the composite oxide other than silicon by adding an acid to prepare a dispersion liquid of silica-based particles.

Abstract: There is provided an antireflective laminate having a low refractive index and excellent mechanical strength, which comprises a coating layer of an ionizing radiation curing-type resin composition comprising ionizing radiation curing group-containing hollow silica fine particles. The antireflective laminate comprises a light transparent base material and at least a low refractive index layer having a refractive index of not more than 1.45 provided on the light transparent base material, wherein the low refractive index layer comprises an ionizing radiation curing-type resin composition and silica fine particles having an outer shell layer with the interior of the silica fine particles being porous or void, and, for a part or all of the silica fine particles, at least a part of the surface of the silica fine particle has been treated with an ionizing radiation curing group-containing silane coupling agent.

Abstract: There is provided an antireflective laminate having a low refractive index and excellent mechanical strength, which comprises a coating layer of an ionizing radiation curing-type resin composition comprising ionizing radiation curing group-containing hollow silica fine particles. The antireflective laminate comprises a light transparent base material and at least a low refractive index layer having a refractive index of not more than 1.45 provided on the light transparent base material, wherein the low refractive index layer comprises an ionizing radiation curing-type resin composition and silica fine particles having an outer shell layer with the interior of the silica fine particles being porous or void, and, for a part or all of the silica fine particles, at least a part of the surface of the silica fine particle has been treated with an ionizing radiation curing group-containing silane coupling agent.

Abstract: Hollow silica-based particles having cavities inside the outer shell having a low refractive index. The method of producing the silica-based particles comprises the following steps (a) and (b): (a) a step in which, when an aqueous silicate solution and/or an acidic silicic acid solution and an aqueous solution of an alkali-soluble inorganic compound are simultaneously added in an alkali aqueous solution to prepare a dispersion liquid of composite oxide particles, an electrolytic salt is added at the molar ratio of a mole number of the electrolytic salt (ME) versus that of SiO2 (MS) [(ME)/(MS)] in the range from 0.1 to 10, and (b) a step of furthermore adding an electrolytic salt, if necessary, to the dispersion liquid of composite oxide particles and then removing at least a portion of elements constituting the composite oxide other than silicon by adding an acid to prepare a dispersion liquid of silica-based particles.

Abstract: There is provided an antireflective laminate having a low refractive index and excellent mechanical strength, which comprises a coating layer of an ionizing radiation curing-type resin composition comprising ionizing radiation curing group-containing hollow silica fine particles. The antireflective laminate comprises a light transparent base material and at least a low refractive index layer having a refractive index of not more than 1.45 provided on the light transparent base material, wherein the low refractive index layer comprises an ionizing radiation curing-type resin composition and silica fine particles having an outer shell layer with the interior of the silica fine particles being porous or void, and, for a part or all of the silica fine particles, at least a part of the surface of the silica fine particle has been treated with an ionizing radiation curing group-containing silane coupling agent.

Abstract: A coating liquid for forming on a substrate surface a hard coat film which exhibits a high refractive index, being excellent in resistance to hot water, weather resistance, scuffing resistance, attrition resistance and dye affinity, and which does not exhibit photochromism, is provided. A coating liquid for forming a hard coat film, comprises a matrix-forming component and composite metal oxide particles of 1 to 100 nm average particle size, composed either of an iron oxide component and a titanium oxide component used at a specified ratio or an iron oxide component, a titanium oxide component and a silica component used at a specified ratio. A substrate coated with a hard coat film is formed by applying the above coating liquid to the substrate surface and effecting drying.

Abstract: A file having a polypropyrene base sheet and a fastener assembly that includes a polypropyrene base member thermally bonded to the polypropyrene base sheet. A relatively thin polypropyrene sheet, such as a polypropyrene sheet having a thickness of about 0.3 mm or less, is sturdy and is used, thus securing a large mechanical strength to support the fastener assembly. The polypropyrene base member is bonded to a relatively thin polypropyrene base sheet by an ultrasonic bonding. The ultrasonic bonding achieves a strong connection between the polypropyrene member and the relatively thin polypropyrene sheet.

Abstract: Disclosed is a film-forming coating solution comprising a matrix and a fine particulate compound oxide composed of oxides of titanium, silicon and zirconium and/or aluminum. This film-forming coating solution can form a colorless and transparent film of high refractive index which is excellent in dyeing property and adhesion to the substrate. Also disclosed is a synthetic resin lens of high refractive index having a film (hard coat film) formed from the film-forming coating solution on the surface. This synthetic resin lens is free from interference fringe and has a reduced thickness.