Abstract: A curable resin composition which provides a cured product excellent in impact resistance and flexural modulus and has a low viscosity comprising a component (A), a component (B) and a component (C). The component (A) is a compound represented by formula (1), In formula (1), R is hydrogen or a hydrocarbon group having 1 to 4 carbon atoms. The hydrocarbon group optionally has a substituent. The component (B) is a compound having one or more caprolactone modified structures and two or more radically polymerizable groups per molecule, and the component (C) is a radical polymerization initiator.

Abstract: A curable resin composition which provides a cured product excellent in impact resistance and flexural modulus and has a low viscosity comprising a component (A), a component (B) and a component (C). The component (A) is a compound represented by formula (1), wherein in formula (1), R is hydrogen or a hydrocarbon group having 1 to 4 carbon atoms, and the hydrocarbon group optionally has a substituent, wherein the component (B) is a compound having 3 or more to 15 or less of oxyethylene groups or oxypropylene groups and two or more radically polymerizable groups per molecule, and wherein the component (C) is a radical polymerization initiator.

Abstract: A cured product contains a dispersant, inorganic particles, and a resin that is a product of polymerization or copolymerization of a curable resin. The dispersant contains a compound represented by a formula R—X, wherein R represents a group having an acryloyloxy group or a methacryloyloxy group at an end of the molecule thereof, and X represents a carboxy group. The dispersant content is 10 parts by volume to 20 parts by volume relative to 100 parts by volume of the cured product. The curable resin contains at least one monomer having an N number of polymerizable reactive group, wherein N represents an integer of 2 or more. The proportion of the at least one monomer is 25 parts by volume to 76 parts by volume relative to 100 parts by volume of the cured product.

Abstract: In a diffractive optical element including a base material, a first resin layer having a diffraction grating shape including plural concentric ring bands, and a second resin layer containing an inorganic particle, the inorganic particle is adjusted to have a number mean particle diameter of 10 nm or less, a first peak in a region in which particle diameters are 2 nm or more and 7.9 nm or less, and a second peak in a region in which particle diameters are larger than those of the first peak in a grain size distribution on a volumetric basis, with the ratio of the maximum intensity of the second peak to the maximum intensity of the first peak being 0.3 or more and 0.8 or less in a grain size distribution.

Abstract: A curable resin composition which provides a cured product excellent in impact resistance and flexural modulus and has a low viscosity comprising a component (A), a component (B) and a component (C). The component (A) is a compound represented by formula (1), wherein in formula (1), R is hydrogen or a hydrocarbon group having 1 to 4 carbon atoms, and the hydrocarbon group optionally has a substituent, wherein the component (B) is a compound having 3 or more to 15 or less of oxyethylene groups or oxypropylene groups and two or more radically polymerizable groups per molecule, and wherein the component (C) is a radical polymerization initiator.

Abstract: A curable resin composition which provides a cured product excellent in impact resistance and flexural modulus and has a low viscosity comprising a component (A), a component (B) and a component (C). The component (A) is a compound represented by formula (1), In formula (1), R is hydrogen or a hydrocarbon group having 1 to 4 carbon atoms. The hydrocarbon group optionally has a substituent. The component (B) is a compound having one or more caprolactone modified structures and two or more radically polymerizable groups per molecule, and the component (C) is a radical polymerization initiator.

Abstract: In a diffractive optical element including a base material, a first resin layer having a diffraction grating shape including plural concentric ring bands, and a second resin layer containing an inorganic particle, the inorganic particle is adjusted to have a number mean particle diameter of 10 nm or less, a first peak in a region in which particle diameters are 2 nm or more and 7.9 nm or less, and a second peak in a region in which particle diameters are larger than those of the first peak in a grain size distribution on a volumetric basis, with the ratio of the maximum intensity of the second peak to the maximum intensity of the first peak being 0.3 or more and 0.8 or less in a grain size distribution.

Abstract: A cured product contains a dispersant, inorganic particles, and a resin that is a product of polymerization or copolymerization of a curable resin. The dispersant contains a compound represented by a formula R—X, wherein R represents a group having an acryloyloxy group or a methacryloyloxy group at an end of the molecule thereof, and X represents a carboxy group. The dispersant content is 10 parts by volume to 20 parts by volume relative to 100 parts by volume of the cured product. The curable resin contains at least one monomer having an N number of polymerizable reactive group, wherein N represents an integer of 2 or more. The proportion of the at least one monomer is 25 parts by volume to 76 parts by volume relative to 100 parts by volume of the cured product.

Abstract: A styrene based resin composition having a low linear thermal expansion coefficient and high formability, a formed article thereof, and an optical element made from the formed article are provided. The formed article is produced by forming a styrene based resin composition containing a styrene based resin and silica particles, wherein the number average particle diameter of primary particles of the silica particles is 0.5 nm or more and 40 nm or less, and the content of the silica particles is 40 percent by volume or more and 75 percent by volume or less relative to a total of the styrene based resin and the silica particles.

Abstract: A styrene based resin composition having a low linear thermal expansion coefficient and high formability, a formed article thereof, and an optical element made from the formed article are provided. The formed article is produced by forming a styrene based resin composition containing a styrene based resin and silica particles, wherein the number average particle diameter of primary particles of the silica particles is 0.5 nm or more and 40 nm or less, and the content of the silica particles is 40 percent by volume or more and 75 percent by volume or less relative to a total of the styrene based resin and the silica particles.

Abstract: An organic-inorganic composite molded product formed by molding a composite material of an organic resin and inorganic fine particles is provided, and in this molded product, the average primary particle diameter of the inorganic fine particles is 1 to 30 nm, the concentration of the inorganic fine particles is 25 to 50 percent by volume, and the porosity is 20 to 55 percent by volume. Accordingly, an organic-inorganic composite molded product having a small content of the inorganic fine particles and a significantly low average coefficient of linear expansion of 20*10?6 to ?110*10?6/degree Celsius can be manufactured.