Abstract: According to the present invention, there can be provided a photocurable composition comprising a sulfur (a) having a cyclic structure represented by the following formula (1), an episulfide compound (b), and a photopolymerization initiator (c), wherein the content of the sulfur (a) is 1 to 28 parts by mass, with respect to the total mass (100 parts by mass) of the sulfur (a) and the episulfide compound (b):

Abstract: A composition for a high refractive index, low dispersion resin for a close-contact double layer-type composite diffractive optical element that is highly photocurable and provides a high productivity, and a close-contact double layer-type composite diffractive optical element using such composition are provided. A composition for a high refractive index, low dispersion resin for a close-contact double layer-type composite diffractive optical element includes a thiol compound represented by general formula (1) or an oligomer synthesized by use of a thiol compound represented by general formula (1) (A component); and an ene compound including two or more polymerizable unsaturated bonds (B component). (In the formula, p represents an integer of 2 to 5; Xp and Zp independently represent a hydrogen atom or a mercaptomethyl group; a ratio of sulfur atoms in a molecule is 40 to 80% by mass; and the number of thiol groups is 3 or larger.).

Abstract: According to the present invention, it is possible to provide a photocurable composition which comprises a cyclic compound (a) represented by formula (1), an episulfide compound (b), and a photopolymerization initiator (c). In a preferred embodiment, the proportion of the cyclic compound (a) in the photocurable composition is 5-80 mass %, the proportion of the episulfide compound (b) is 20-95 mass %, and the proportion of the photopolymerization initiator (c) is 0.1-10 parts by mass per 100 parts by mass of the sum of the cyclic compound (a) and the episulfide compound (b). In the formula, C represents a carbon atom, X represents S, Se, or Te, and a to f are integers of 0-3, provided that 8?(a+c+e)?1, 8?(b+d+f)?2, and (b+d+f)?(a+c+e).

Abstract: The present invention can provide a method for producing a cured product of an episulfide-based resin, the method having: (A) a step for obtaining a composition for a resin by mixing compound (a), compound (b) and a polymerization catalyst; (B) a step for pouring the composition for a resin into a mold; and (C) a step in which, by increasing the temperature of a heating medium, the composition for a resin is polymerized in the heating medium that contains a liquid having a thermal conductivity of 0.2 W/m·K or higher, or in a shower of the heating medium. The maximum temperature of the heating medium in step (C) is 55 to 110° C. (a) A compound which has two episulfide groups per molecule and which is represented by formula (1): wherein m represents an integer from 0 to 4 and n represents an integer from 0 to 2 (b) A compound having one or more thiol groups per molecule.

Abstract: A composition for a high refractive index, and low dispersion resin for a close-contact double layer-type composite diffractive optical element that is highly photocurable and provides a high productivity, and a close-contact double layer-type composite diffractive optical element using such composition are provided. A composition for a high refractive index, and low dispersion resin for a close-contact double layer-type composite diffractive optical element includes a thiol compound represented by general formula (1) or an oligomer synthesized by use of a thiol compound represented by general formula (1) (A component); and an ene compound including two or more polymerizable unsaturated bonds (B component). (In the formula, p represents an integer of 2 to 5; Xp and Zp independently represent a hydrogen atom or a mercaptomethyl group; a ratio of sulfur atoms in a molecule is 40 to 80% by mass; and the number of thiol groups is 3 or larger.

Abstract: According to the present invention, it is possible to provide a photocurable composition which comprises a cyclic compound (a) represented by formula (1), an episulfide compound (b), and a photopolymerization initiator (c). In a preferred embodiment, the proportion of the cyclic compound (a) in the photocurable composition is 5-80 mass %, the proportion of the episulfide compound (b) is 20-95 mass %, and the proportion of the photopolymerization initiator (c) is 0.1-10 parts by mass per 100 parts by mass of the sum of the cyclic compound (a) and the episulfide compound (b). In the formula, C represents a carbon atom, X represents S, Se, or Te, and a to f are integers of 0-3, provided that 8?(a+c+e)?1, 8?(b+d+f)?2, and (b+d+f)?(a+c+e).

Abstract: The present invention is able to provide a curable composition which contains a poly(meth)acrylate compound having a fluorene ring (component (A)), a polythiol compound having a thioalkyl structure (component (B)), an ene compound having a polycyclic aromatic hydrocarbon skeleton (component (C)), and a polymerization initiator (component (D)). A curable composition according to the present invention is especially useful as an adhesive for optical applications, and has high refractive index as an optical characteristic, while having low contractility, photocurability, colorlessness and transparency, viscosity suitable for work, and the like.

Abstract: According to the present invention, a curable composition can be provided, said composition being characterized by comprising: (A) an episulfide compound; and (B) a photobase generator comprising an organoboron compound represented by general formula (1) below: (In general formula (1), R1, R2, R3, R4 and R5 may be the same as or different from one another and independently represent an alkyl group having 1 to 8 carbon atoms; and Ar1, Ar2 and Ar3 may be the same as or different from one another and independently represent a group selected from the group consisting of a phenyl group, a naphthyl group, an anthracenyl group and a phenanthryl group, each of which may have a substituent selected from the group consisting of an alkyl group, an aryl group, an alkenyl group, a cycloalkyl group and a heterocyclic group.

Abstract: The present invention can provide a method for producing a cured product of an episulfide-based resin, the method having: (A) a step for obtaining a composition for a resin by mixing compound (a), compound (b) and a polymerization catalyst; (B) a step for pouring the composition for a resin into a mold; and (C) a step in which, by increasing the temperature of a heating medium, the composition for a resin is polymerized in the heating medium that contains a liquid having a thermal conductivity of 0.2 W/m·K or higher, or in a shower of the heating medium. The maximum temperature of the heating medium in step (C) is 55 to 110° C. (a) A compound which has two episulfide groups per molecule and which is represented by formula (1): wherein m represents an integer from 0 to 4 and n represents an integer from 0 to 2 (b) A compound having one or more thiol groups per molecule.

Abstract: By using a method for producing a composition for an optical material using (a) sulfur, (b) a compound having two intramolecular episulfide groups, (c) a compound having one or more (preferably two) SH groups, and (d) an amine compound having a specific structure, in which compound (a) and compound (c) are pre-polymerized in the presence of compound (b) using compound (d) as the pre-polymerization catalyst, the present invention provides a polymerizable composition for an optical material in which the viscosity elevation speed during pre-polymerization is slow and the reaction temperature is approximately room temperature, and that has a low viscosity and shows little increase in viscosity.

Abstract: The present invention addresses the problem of providing: a catalyst for preliminary reaction and a preliminary reaction method, which are suitable for a composition that is obtained by adding a thiol compound and an isocyanate compound to an episulfide compound; and a polymerizable composition for optical materials, which is capable of preventing yellowing of an optical material which contains a composition that is obtained by adding a thiol compound and an isocyanate compound to an episulfide compound.

Abstract: According to the present invention, a composition for optical material, which is capable of providing a homogeneous optical material, can be prepared through pre-polymerization reaction between (a) an inorganic compound having a sulfur atom and (b) an episulfide compound using a hindered amine as a catalyst, followed by mixing with (c) a polythiol compound and (d) a polyisocyanate compound. Moreover, this composition for optical material can be polymerized and cured to thereby provide an optical material having high refractive index (ne of 1.73 or higher), high strength (an elongation of 13% or more in three-point bend test and good drilling resistance), and high heat resistance (a softening point of 70° C. or higher, as measured by TMA).

Abstract: A composition for an optical material includes (a) a compound having two ?-epithiopropyl groups and having a specific structure, (b) a compound having one ?-epithiopropyl group and one glycidyl group and having a specific structure, (c) polyisocyanate and (d) polythiol, enables the prevention of the occurrence of such a defect that peeling traces linger on a lens. In the composition for an optical material, an embodiment in which (e) sulfur is additionally contained is preferred. Another embodiment of the present invention is a method for producing an optical material, characterized by adding an onium salt as a polymerization catalyst to the composition for an optical material in an amount of 0.0001 to 10% by mass relative to the total amount of the compound (a), the compound (b), polyisocyanate (c) and polythiol (d) and then polymerizing and curing the resultant mixture.

Abstract: The present invention is able to provide an optical material composition containing: a polythiol compound satisfying one of the below mentioned i) through iii); and a polyepoxy compound and/or a polyepisulfide compound of which i) the ammonium cation concentration is 0.1-150 ?mol/kg, ii) the thiocyanate anion concentration is 0.1-300 ?mol/kg, or iii) the ammonium cation concentration is 0.1-150 ?mol/kg, the thiocyanate anion concentration is 0.1-300 ?mol/kg, and furthermore the ion concentration product of the ammonium cations and the thiocyanate anions is 0.01-15000 (?mol/kg)2.

Abstract: According to the present invention, a curable composition can be provided, said composition being characterized by comprising: (A) an episulfide compound; and (B) a photobase generator comprising an organoboron compound represented by general formula (1) below: (In general formula (1), R1, R2, R3, R4 and R5 may be the same as or different from one another and independently represent an alkyl group having 1 to 8 carbon atoms; and Ar1, Ar2 and Ar3 may be the same as or different from one another and independently represent a group selected from the group consisting of a phenyl group, a naphthyl group, an anthracenyl group and a phenanthryl group, each of which may have a substituent selected from the group consisting of an alkyl group, an aryl group, an alkenyl group, a cycloalkyl group and a heterocyclic group.

Abstract: With the present invention, it is possible to provide a composition for optical materials which comprises: a polythiol compound satisfying any one of the following i) to iii) i) the compound has an ammonium cation concentration of 0.1 to 400 ?mol/kg, ii) the compound has a thiocyanic acid anion concentration of 0.1 to 600 ?mol/kg, and iii) the compound has an ammonium cation concentration of 0.1 to 400 ?mol/kg and a thiocyanic acid anion concentration of 0.1 to 600 ?mol/kg, the product of the ammonium cation concentration and the thiocyanic acid anion concentration being 0.01 to 100,000 (?mol/kg)2; and a polyisocyanate compound.

Abstract: A composition for an optical material includes (a) a compound having two ?-epithiopropyl groups and having a specific structure, (b) a compound having one ?-epithiopropyl group and one glycidyl group and having a specific structure, (c) polyisocyanate and (d) polythiol, enables the prevention of the occurrence of such a defect that peeling traces linger on a lens. In the composition for an optical material, an embodiment in which (e) sulfur is additionally contained is preferred. Another embodiment of the present invention is a method for producing an optical material, characterized by adding an onium salt as a polymerization catalyst to the composition for an optical material in an amount of 0.0001 to 10% by mass relative to the total amount of the compound (a), the compound (b), polyisocyanate (c) and polythiol (d) and then polymerizing and curing the resultant mixture.

Abstract: The present invention includes a polymerizable composition for optical materials, which contains a thiourethane oligomer that is obtained by preliminarily reacting the whole or a part of a thiol compound and an isocyanate compound in a composition that contains an episulfide compound, the thiol compound and the isocyanate compound, while using a compound represented by formula (2) below as a catalyst for preliminary reaction. (In formula (2), R represents an alkyl group having 1 to 4 carbon atoms; and X represents an organic group which has 2 to 11 carbon atoms and contains a vinyl group, a vinylidene group or a vinylene group.

Abstract: According to the present invention, a composition for optical material, which is capable of providing a homogeneous optical material, can be prepared through pre-polymerization reaction between (a) an inorganic compound having a sulfur atom and (b) an episulfide compound using a hindered amine as a catalyst, followed by mixing with (c) a polythiol compound and (d) a polyisocyanate compound. Moreover, this composition for optical material can be polymerized and cured to thereby provide an optical material having high refractive index (ne of 1.73 or higher), high strength (an elongation of 13% or more in three-point bend test and good drilling resistance), and high heat resistance (a softening point of 70° C. or higher, as measured by TMA).

Abstract: By using a method for producing a composition for an optical material using (a) sulfur, (b) a compound having two intramolecular episulfide groups, (c) a compound having one or more (preferably two) SH groups, and (d) an amine compound having a specific structure, in which compound (a) and compound (c) are pre-polymerized in the presence of compound (b) using compound (d) as the pre-polymerization catalyst, the present invention provides a polymerizable composition for an optical material in which the viscosity elevation speed during pre-polymerization is slow and the reaction temperature is approximately room temperature, and that has a low viscosity and shows little increase in viscosity.