Abstract: A process for producing pentaerythritol mercaptocarboxylic ester by reacting pentaerythritol with a mercaptocarboxylic acid having a content of thioester formed by condensation of two molecules of the acid of 5% or below (in terms of area percentage) as determined by the high-performance liquid chromatography in the case of the total area of the mercaptocarboxylic acid and thioester formed by intermolecular condensation of the acid is taken as 100%.

Abstract: A process for producing a (poly)thiol compound for an optical material. The process involves reacting an organic (poly)halogen compound or a (poly)alcohol compound with thiourea to produce an isothiuronium salt and hydrolyzing the isothiuronium salt in the presence of ammonia water to thereby produce the (poly)thiol compound, wherein the thiourea has a calcium content of not more than 1.0 wt %.

Abstract: A process for producing pentaerythritol mercaptocarboxylic ester by reacting pentaerythritol with a mercaptocarboxylic acid having a content of thioester formed by condensation of two molecules of the acid of 5% or below (in terms of area percentage) as determined by the high-performance liquid chromatography in the case of the total area of the mercaptocarboxylic acid and thioester formed by intermolecular condensation of the acid is taken as 100%.

Abstract: Provided is a process for producing a polythiol compound for an optical material, the method includes reacting 2-mercaptoethanol with an epihalohydrin compound to give polyalcohol, and preparing a polythiol compound through the polyalcohol, wherein a content of bis(2-hydroxyethyl)disulfide in the 2-mercaptoethanol is 0.5 wt % or less.

Abstract: Disclosed is a process for producing effectively a high performance optical material (e.g. a lens) made of a polyurethane resin, which is transparent and colorless without a strain. In this process, the optical material is produced without causing striation or clouding by polymerizing a polymerizable composition comprising a polythiol compound and a polyiso(thio)cyanate compound, and characterized in that a water content in the composition is 10 to 300 ppm.

Abstract: A process for producing pentaerythritol mercaptocarboxylic ester by reacting pentaerythritol with a mercaptocarboxylic acid having a content of thioester formed by condensation of two molecules of the acid of 5% or below (in terms of area percentage) as determined by the high-performance liquid chromatography in the case of the total area of the mercaptocarboxylic acid and thioester formed by intermolecular condensation of the acid is taken as 100%.

Abstract: Pentaerythritol which contains none of the alkali metals and the alkaline earth metals or which contains at least one of these in a total amount of 1.0 weight % or smaller is reacted with a mercaptocarboxylic acid to produce a pentaerythritol mercaptocarboxylic acid ester.

Abstract: Disclosed is a process for producing a (poly)thiol compound for an optical material. The process comprises reacting an organic (poly)halogen compound or a (poly)alcohol compound with thiourea to produce an isothiuronium salt and hydrolyzing the isothiuronium salt to thereby produce the (poly)thiol compound, wherein the thiourea has a calcium content of not more than 1.0 wt %.

Abstract: Provided is a process for producing a polythiol compound for an optical material, the method includes reacting 2-mercaptoethanol with an epihalohydrin compound to give polyalcohol, and preparing a polythiol compound through the polyalcohol, wherein a content of bis(2-hydroxyethyl) disulfide in the 2-mercaptoethanol is 0.5 wt % or less.

Abstract: A composition for making a high-refractive-index resin contains a polythiol compound and a compound containing at least two iso(thio)cyanato groups, the polythiol compound having a dithioacetal, dithioketal, orthotrithioformic ester, or orthotetrathiocarbonic ester skeleton. The molar ratio of the mercapto group to the iso(thio)cyanato group in the composition is greater than 1.0 but not more than 3.0. A method for making a resin by curing the composition, a resin prepared by curing the composition, an optical element made from the resin, and a lens made from the optical element are also provided.

Abstract: A resin composition for an optical material that has excellent balance of refractive index of resin, Abbe number, heat resistance, specific gravity, and resin strength, a resin obtained by curing the resin composition, and an optical material are provided. A polymerizable composition comprising the following is used: An alicyclic isocyanate compound represented by the formula (1) and/or the formula (2): ?(In the formula (1), n represents integer of 0 to 3) ?and (a) at least one compound of the polythiol compound having at least two thiol groups in one molecule and/or the polythiol compound having at least two thiol groups and at least one (poly)sulfide bond other than the thiol group in one molecule, and (b) at least one compound of the polyhydroxy compound having at least two hydroxy groups in one molecule and/or the (poly)hydroxy(poly)mercapto compound having at least one hydroxy group and at least one thiol group.

Abstract: A composition for making a high-refractive-index resin contains a polythiol compound and a compound containing at least two iso(thio)cyanato groups, the polythiol compound having a dithioacetal, dithioketal, orthotrithioformic ester, or orthotetrathiocarbonic ester skeleton. The molar ratio of the mercapto group to the iso(thio)cyanato group in the composition is greater than 1.0 but not more than 3.0. A method for making a resin by curing the composition, a resin prepared by curing the composition, an optical element made from the resin, and a lens made from the optical element are also provided.

Abstract: A composition for making a high-refractive-index resin contains a polythiol compound and a compound containing at least two iso(thio)cyanato groups, the polythiol compound having a dithioacetal, dithioketal, orthotrithioformic ester, or orthotetrathiocarbonic ester skeleton. The molar ratio of the mercapto group to the iso(thio)cyanato group in the composition is greater than 1.0 but not more than 3.0. A method for making a resin by curing the composition, a resin prepared by curing the composition, an optical element made from the resin, and a lens made from the optical element are also provided.

Abstract: A composition for making a high-refractive-index resin contains a polythiol compound and a compound containing at least two iso(thio)cyanato groups, the polythiol compound having a dithioacetal, dithioketal, orthotrithioformic ester, or orthotetrathiocarbonic ester skeleton. The molar ratio of the mercapto group to the iso(thio)cyanato group in the composition is greater than 1.0 but not more than 3.0. A method for making a resin by curing the composition, a resin prepared by curing the composition, an optical element made from the resin, and a lens made from the optical element are also provided.

Abstract: This invention provides a polymerizable composition for a lens with a high refractive index comprising at least one polythiol compound represented general formula (1): R—(SCH2SH)n  (1) where R is an organic residue except an aromatic group and n is an integer of at least 1, having at least two intramolecular mercapto groups and at least one compound having an intramolecular functional group which can react with a mercapto group; a resin prepared by polymerizing the composition; an optical element and a lens made of the resin; and a process for preparing a thiol compound comprising the steps of reacting a compound represented by general formula (2): HS—R1(—S—R2)m  (2) where m is an integer of at least 1; R1 represents an aromatic, aliphatic, alicyclic or heterocyclic organic residue or aliphatic, alicyclic or heterocyclic organic residue with an aromatic ring or a sulfur atom in its chain; and R2 represents a protective group, with a compound having a functiona

Abstract: A polymerizable composition for a lens with a high refractive index comprising at least one polythiol compound represented general formula (1): R—(SH2SH)n  (1) where R is an organic residue except an aromatic group and n is an integer of at least 1, having at least two intramolecular mercapto groups and at least one compound having an intramolecular functional group which can react with a mercapto group; a resin prepared by polymerizing the composition; an optical element and a lens made of the resin; and a process for preparing a thiol compound comprising the steps of reacting a compound represented by general formula (2): HS—R1(—S—R2)m  (2) where m is an integer of at least 1; R1 represents an aromatic, aliphatic, alicyclic or heterocyclic organic residue or aliphatic, alicyclic or heterocyclic organic residue with an aromatic ring or a sulfur atom in its chain; and R2 represents a protective group, with a compound having a functional group which can react wit

Abstract: This invention provides a polymerizable composition for a lens with a high refractive index comprising at least one polythiol compound represented general formula (1):

Abstract: A polymerizable composition for a lens with a high refractive index comprising at least one polythiol compound represented general formula (1):

Abstract: This invention provides a polymerizable composition for a lens with a high refractive index comprising at least one polythiol compound represented general formula (1): R—(SH2SH)n  (1) where R is an organic residue except an aromatic group and n is an integer of at least 1, having at least two intramolecular mercapto groups and at least one compound having an intramolecular functional group which can react with a mercapto group; a resin prepared by polymerizing the composition; an optical element and a lens made of the resin; and a process for preparing a thiol compound comprising the steps of reacting a compound represented by general formula (2): HS—R1(—S—R2)m  (2) where m is an integer of at least 1; R1 represents an aromatic, aliphatic, alicyclic or heterocyclic organic residue or aliphatic, alicyclic or heterocyclic organic residue with an aromatic ring or a sulfur atom in its chain; and R2 represents a protective group, with a compound having a functional g

Abstract: This invention provides a polymerizable composition for a lens with a high refractive index comprising at least one polythiol compound represented general formula (1):