Abstract: There is provided a method of producing a multilayer optical recording medium through which the occurrence of burrs is reduced. The method of producing a multilayer optical recording medium includes, when a UV curable adhesive is interposed between a first disk and a second disk, the first disk and the second disk are rotated, and when at least one of the vicinities of inner circumferential edges and the vicinities of outer circumferential edges of the first disk and the second disk is masked with a mask member, emitting ultraviolet rays for preliminarily curing the UV curable adhesive from the side of a light emission surface of the first disk during rotation.

Abstract: Provided is an optical recording medium capable of suppressing sticking between the optical recording mediums in a case where a plurality of optical recording mediums are superimposed on each other. The optical recording medium includes an optical recording medium main body having a first surface and a second surface, and a first convex structure layer provided on the first surface. The first convex structure layer has a surface provided with a plurality of first convexities, and includes first particles and a first resin material. The plurality of first convexities are formed by a part of the first particles included in the first convex structure layer, the part of the first particles protruding from the surface of the first convex structure layer.

Abstract: There is provided an optical recording medium substrate including a polycarbonate in which an average molecular weight is in a range from 15000 to 16000, and mass per unit volume at 25° C. is in a range from 1.1930 g/cm3 to 1.2000 g/cm3.

Abstract: There is provided a method of producing a multilayer optical recording medium through which the occurrence of burrs is reduced. The method of producing a multilayer optical recording medium includes, when a UV curable adhesive is interposed between a first disk and a second disk, the first disk and the second disk are rotated, and when at least one of the vicinities of inner circumferential edges and the vicinities of outer circumferential edges of the first disk and the second disk is masked with a mask member, emitting ultraviolet rays for preliminarily curing the UV curable adhesive from the side of a light emission surface of the first disk during rotation.

Abstract: An optical recording medium includes a first disk, a second disk, and an adhesive layer for bonding the first disk to the second disk. The first disk and the second disk each include a substrate having a first surface and a second surface and having a gradient on an outer peripheral portion of the second surface, two or more information signal layers disposed on the first surface, an intermediate layer disposed between adjacent information signal layers, and a cover layer covering the two or more information signal layers and the intermediate layer. The second surface of the substrate included in the first disk faces the second surface of the substrate included in the second disk with the adhesive interposed therebetween.

Abstract: An optical recording medium includes a first disk, a second disk, and an adhesive layer for bonding the first disk to the second disk. The first disk and the second disk each include a substrate having a first surface and a second surface and having a gradient on an outer peripheral portion of the second surface, two or more information signal layers disposed on the first surface, an intermediate layer disposed between adjacent information signal layers, and a cover layer covering the two or more information signal layers and the intermediate layer. The second surface of the substrate included in the first disk faces the second surface of the substrate included in the second disk with the adhesive interposed therebetween.

Abstract: There is provided an optical recording medium substrate including a polycarbonate in which an average molecular weight is in a range from 15000 to 16000, and mass per unit volume at 25° C. is in a range from 1.1930 g/cm3 to 1.2000 g/cm3.

Abstract: Provided is an optical recording medium including: two discs, each of which includes a substrate and a plurality of recording layers; and an attachment layer which is provided between the two discs and includes ultraviolet curable resin, wherein thickness of each of the substrates in the two discs is equal to or greater than 0.3 mm and equal to or less than 0.545 mm, wherein transmittance of the two discs is equal to or less than 20%, and wherein inversion rates on both surface sides of the attachment layer are equal or substantially equal to each other, and are equal to or greater than 70%.

Abstract: An economical batchwise production method of polyamide with good quality by the polycondensation in which a diamine component including 70 mol % or more of a xylylenediamine which includes 20 mol % or more of p-xylylenediamine is added to a dicarboxylic acid component in a batchwise reaction tank equipped with a partial condenser. The diamine component is added while maintaining the whole reaction system in fluid state under pressure. The pressure is reduced during the time that the molar ratio is within a specific range while continuing the addition.

Abstract: Provided is an optical recording medium including: two discs, each of which includes a substrate and a plurality of recording layers; and an attachment layer which is provided between the two discs and includes ultraviolet curable resin, wherein thickness of each of the substrates in the two discs is equal to or greater than 0.3 mm and equal to or less than 0.545 mm, wherein transmittance of the two discs is equal to or less than 20%, and wherein inversion rates on both surface sides of the attachment layer are equal or substantially equal to each other, and are equal to or greater than 70%.

Abstract: The present invention provides an apparatus for producing thermoplastic resin pellets of uniform shape. The apparatus includes a batch-type polymerization vessel whose inner pressure can be controlled; a pelletizer for cutting a strand-form thermoplastic resin discharged from the polymerization vessel, thereby forming pellets; a pipe for transferring the pellets to a storage container by pneumatic transportation or suction transportation; a pressure differential measuring unit for determining variation in a pressure difference between the inlet and the outlet of the transfer pipe; and a pressure controlling unit for controlling the inner pressure of the batch-type polymerization vessel on the basis of the variation in the measured pressure difference; wherein the inner pressure of the batch-type polymerization vessel is controlled in relation to a pressure loss in the transfer pipe.

Abstract: A copolyamide resin for molding including a diamine component which includes two or more diamines and a dicarboxylic acid component. The diamine component includes 70 mol % or more of a xylylenediamine which includes 20 mol % or more of p-xylylenediamine and the dicarboxylic acid component includes 70 mol % or more of a straight-chain aliphatic dicarboxylic acid having 6 to 18 carbon atoms. The copolyamide resin contains particles having a major diameter of 50 ?m or more in an amount of 1000 particles/g or less, the particles being made of a polyamide having a melting point higher than that of the copolyamide resin by 20° C. or more when measured by a differential scanning calorimetry. The copolyamide resin has very uniform and stable properties and is excellent in any of mechanical properties, heat resistance, chemical and physical properties, and molding properties. An efficient production method of the copolyamide resin, its resin composition, and its molded article are also described.

Abstract: There is provided an optical recording medium substrate including a polycarbonate in which an average molecular weight is in a range from 15000 to 16000, and mass per unit volume at 25° C. is in a range from 1.1930 g/cm3 to 1.2000 g/cm3.

Abstract: An optical recording medium includes: a substrate; an information recording layer formed on the substrate for recording and reproducing an information signal by irradiation with light; and a light transmission layer formed on the information recording layer and transmitting the light, the storage elastic modulus of the light transmission layer at ?5° C. being within a range of 1500 MPa or less.

Abstract: A copolyamide resin for molding including a diamine component which includes two or more diamines and a dicarboxylic acid component. The diamine component includes 70 mol % or more of a xylylenediamine which includes 20 mol % or more of p-xylylenediamine and the dicarboxylic acid component includes 70 mol % or more of a straight-chain aliphatic dicarboxylic acid having 6 to 18 carbon atoms. The copolyamide resin contains particles having a major diameter of 50 ?m or more in an amount of 1000 particles/g or less, the particles being made of a polyamide having a melting point higher than that of the copolyamide resin by 20° C. or more when measured by a differential scanning calorimetry. The copolyamide resin has very uniform and stable properties and is excellent in any of mechanical properties, heat resistance, chemical and physical properties, and molding properties. An efficient production method of the copolyamide resin, its resin composition, and its molded article are also described.

Abstract: A process for producing polyamide which comprises directly melt polymerizing a diamine component, which comprises 70% by mole or more of xylylenediamine comprising 20% by mole or more of para-xylylenediamine, and a dicarboxylic acid component in the substantial absence of solvents in a reaction apparatus of the batch type, wherein a stirring apparatus disposed in the reaction apparatus and used for stirring the melted polymer in the apparatus comprises: (1) a rotating shaft connected to a driving member for stirring, (2) two or more stirring rods disposed in the substantially vertical direction which are cylinder-shaped members or plate-shaped members moving along the circumference of a circle having the center at the rotating shaft, and (3) a connecting member which connects the rotating shaft and the stirring rods; distances between the center line of the rotating shaft and center lines of the two or more stirring rods are each 15% or greater of the inner diameter of the reaction apparatus; the connecting m

Abstract: An economical batchwise production method of polyamide with good quality by the polycondensation in which a diamine component including 70 mol % or more of a xylylenediamine which includes 20 mol % or more of p-xylylenediamine is added to a dicarboxylic acid component in a batchwise reaction tank equipped with a partial condenser. The diamine component is added while maintaining the whole reaction system in fluid state under pressure. The pressure is reduced during the time that the molar ratio is within a specific range while continuing the addition.

Abstract: An object of the present invention is to provide a process for producing thermoplastic resin pellets, which realizes production of pellets of uniform shape. Another object of the present invention is to provide an apparatus for producing the thermoplastic resin pellets. The invention provides a process for producing thermoplastic resin pellets, including pressurizing the interior of a vessel holding a molten thermoplastic resin, thereby discharging the resin; forming pellets through solidification and cutting of the resin; and transferring the pellets to a storage container via a pipe by a pneumatic transportation or a suction transportation, wherein the amount of the resin discharged is regulated by controlling the pressure in the vessel so that variation in the difference pressure between the inlet and the outlet of the pipe for transferring the pellets is 10% or less.

Abstract: The present invention provides an apparatus for producing thermoplastic resin pellets of uniform shape. The apparatus includes a batch-type polymerization vessel whose inner pressure can be controlled; a pelletizer for cutting a strand-form thermoplastic resin discharged from the polymerization vessel, thereby forming pellets; a pipe for transferring the pellets to a storage container by pneumatic transportation or suction transportation; a pressure differential measuring unit for determining variation in a pressure difference between the inlet and the outlet of the transfer pipe; and a pressure controlling unit for controlling the inner pressure of the batch-type polymerization vessel on the basis of the variation in the measured pressure difference; wherein the inner pressure of the batch-type polymerization vessel is controlled in relation to a pressure loss in the transfer pipe.

Abstract: An optical recording medium includes: a substrate; an information recording layer formed on the substrate for recording and reproducing an information signal by irradiation with light; and a light transmission layer formed on the information recording layer and transmitting the light, the storage elastic modulus of the light transmission layer at ?5° C. being within a range of 1500 MPa or less.