The present invention relates to a bleaching agent comprising: (A) a polymerizable component comprising an aromatic ester compound including two or more allyloxycarbonyl groups, (B) a colouring component comprising particles of a blue pigment (b1), (C) a polymeric dispersing agent to disperse the particles of the colouring component (B) in the polymerizable component (A), the particles of the colouring component (B) having an average size equal to or lower than 400 nm. The present invention also relates to the preparation and use of the above bleaching agent with polymerizable compositions for optical materials.

Disclosed is a 1,3-bisisocyanatomethylcyclohexane composition and an optical resin prepared therefrom. The composition comprises, based on the weight of 1,3-bisisocyanatomethylcyclohexane, a) 65%-95 wt % of trans-1,3-bisisocyanatomethylcyclohexane; b) greater than 0 and less than or equal to 0.5 wt %, preferably 0.02-0.5 wt % of 1,4-bisisocyanatomethylcyclohexane. Preferably, the 1,3-bisisocyanatomethylcyclohexane composition contains greater than 0 and less than or equal to 600 ppm of 1-isocyanatomethyl-3-methylcyclohexane, based on the weight of 1,3-bisisocyanatomethylcyclohexane. The 1,3-bisisocyanatomethylcyclohexane composition is used for preparing an optical resin, which can be applied to produce an optical lens with a better performance in preventing opacification and optical distortion.

Disclosed is a 1,3-bisisocyanatomethylcyclohexane composition and an optical resin prepared therefrom. The composition comprises, based on the weight of 1,3-bisisocyanatomethylcyclohexane, a) 65%-95 wt % of trans-1,3-bisisocyanatomethylcyclohexane; b) greater than 0 and less than or equal to 0.5 wt %, preferably 0.02-0.5 wt % of 1,4-bisisocyanatomethylcyclohexane. Preferably, the 1,3-bisisocyanatomethylcyclohexane composition contains greater than 0 and less than or equal to 600 ppm of 1-isocyanatomethyl-3-methylcyclohexane, based on the weight of 1,3-bisisocyanatomethylcyclohexane. The 1,3-bisisocyanatomethylcyclohexane composition is used for preparing an optical resin, which can be applied to produce an optical lens with a better performance in preventing opacification and optical distortion.

Provided are a cured product of a curable composition including a compound represented by General Formula (1), in which a birefringence Δn at a wavelength of 587 nm is 0.00≤Δn≤0.01; an optical member; a lens; a compound represented by General Formula (1); a curable resin composition containing the compound; a cured product; a diffractive optical element; and a multilayer diffractive optical element.

Pol.sup.1-Sp.sup.a-L.sup.1-Ar-L.sup.2-Sp.sup.b-Pol.sup.2  Genera Formula (1) Ar represents an aromatic ring group represented by a specific formula, L.sup.1 and L.sup.2 represent —O—, Sp.sup.a and Sp.sup.b represent a linking group having the shortest atom number of 11 or more and linking Pol and L, Pol.sup.1 and Pol.sup.2 represent a polymerizable group, and in Sp.sup.a and Sp.sup.b, a linking portion to L.sup.1 or L.sup.2 is —CH.sub.2— and a linking portion to Pol.sup.1 or Pol.sup.2 is a carbon atom.

Provided are a cured product of a curable composition including a compound represented by General Formula (1), in which a birefringence Δn at a wavelength of 587 nm is 0.00≤Δn≤0.01; an optical member; a lens; a compound represented by General Formula (1); a curable resin composition containing the compound; a cured product; a diffractive optical element; and a multilayer diffractive optical element.

Pol.sup.1-Sp.sup.a-L.sup.1-Ar-L.sup.2-Sp.sup.b-Pol.sup.2  Genera Formula (1) Ar represents an aromatic ring group represented by a specific formula, L.sup.1 and L.sup.2 represent —O—, Sp.sup.a and Sp.sup.b represent a linking group having the shortest atom number of 11 or more and linking Pol and L, Pol.sup.1 and Pol.sup.2 represent a polymerizable group, and in Sp.sup.a and Sp.sup.b, a linking portion to L.sup.1 or L.sup.2 is —CH.sub.2— and a linking portion to Pol.sup.1 or Pol.sup.2 is a carbon atom.

Provided is a polythiol composition including a polythiol compound (A) and a compound represented by the following Formula (1), wherein, in high performance liquid chromatography measurement, a peak area of the compound represented by Formula (1) is 9.0 or less with respect to a total peak area 100 of all compounds contained in the polythiol composition. In Formula (1), X represents a carbon atom or a sulfur atom.

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Provided is a cured product of a resin composition including a (meth)acrylate compound and a compound having at least one thiol group, wherein the content of the compound having at least one thiol group in the cured product is 30 mass % or less, and wherein the cured product has a secondary dispersion characteristic of 0.65 or more.

Provided is a cured product of a resin composition including a (meth)acrylate compound and a compound having at least one thiol group, wherein the content of the compound having at least one thiol group in the cured product is 30 mass % or less, and wherein the cured product has a secondary dispersion characteristic of 0.65 or more.

An optical imaging system includes a first lens having negative refractive power, a second lens having negative refractive power, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens. The first to seventh lenses are sequentially disposed from an object side toward an image side. The third lens, the fourth lens, the sixth lens, and the seventh lens are formed of plastic, and the first lens, the second lens, and the fifth lens are formed of glass.

For example, a triazine ring-containing polymer containing a repeating unit structure represented by formula (25) below,

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wherein R.sup.a represents R.sup.102 or R.sup.103, R.sup.102 represents a fluorine atom or a fluoroalkyl group having 1 to 10 carbon atoms, and R.sup.103 represents a crosslinking group.