Abstract: The present invention provides a method for granulating a polyamide or a polyamide composition, whereby it becomes possible to granulate even a polyamide that has such a melt viscosity that the polyamide cannot be pelletized into a strand-like shape easily. In the present invention, a polyamide, whose melt viscosity at glass transition temperature+160° C. and a shear rate of 100 s?1 is 3 Pa·s to 200 Pa·s and whose terminal amino group concentration is 5 ?eq/g to 70 ?eq/g, is melted by heating to a range of glass transition temperature+160° C. to glass transition temperature+180° C. of the polyamide, and then is solidified by dropping the molten polyamide in the form of granules onto a metallic belt, thereby producing granules.

Abstract: The present invention provides a method for granulating a polyamide or a polyamide composition, whereby it becomes possible to granulate even a polyamide that has such a melt viscosity that the polyamide cannot be pelletized into a strand-like shape easily. In the present invention, a polyamide, whose melt viscosity at glass transition temperature+160° C. and a shear rate of 100 s?1 is 3 Pa·s to 200 Pa·s and whose terminal amino group concentration is 5 ?eq/g to 70 ?eq/g, is melted by heating to a range of glass transition temperature+160° C. to glass transition temperature+180° C. of the polyamide, and then is solidified by dropping the molten polyamide in the form of granules onto a metallic belt, thereby producing granules.

Abstract: The invention is a method for producing a polyamide having a melting point of 255° C. or higher through polycondensation of a mixed xylylenediamine containing paraxylylenediamine as a diamine component and a dicarboxylic acid component in a batch reactor, wherein when the diamine component is dropwise added to the dicarboxylic acid component kept in a melt state by heating it to a temperature not lower than a melting point thereof under a pressure of 0.1 MPaG or more with keeping the melt state of a reaction mixture, a temperature of the reaction mixture is maintained at 255° C. or lower until a molar ratio (diamine component/dicarboxylic acid component) of the reaction mixture reaches 0.8, and the temperature of the reaction mixture at the end of the dropwise addition is controlled to be not lower than the melting point of the polyamide. The method enables production of a polyamide having an improved hue and being advantageous with respect to quality.

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: 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 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: A process for producing a polyamide through direct polycondensation of a diamine component, which contains at least 70 mol % of a xylylenediamine containing at least 20 mol % of paraxylylenediamine, and a dicarboxylic acid component, substantially in the absence of a solvent and using a batch reactor equipped with a partial condenser; the process comprising the following steps: (1) a step of feeding the dicarboxylic acid component into the reactor, and then pressurizing the reactor to increase the inner pressure to a pressure of at least 0.1 MPaG, (2) a step of continuously or intermittently adding the diamine component to the dicarboxylic acid component while the pressure inside the reactor is kept at 0.1 MPaG or more and while the reaction system is kept in a uniform flow state as a whole, (3) after the addition of the diamine component, a step of lowering the pressure inside the reactor to atmospheric pressure or less at a pressure-lowering speed of from 0.1 to 1.0 MPa/hr.

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: 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: In a repeated batch production of polyamide, a dicarboxylic acid component and a diamine component fed to a batch reactor are melt-polymerized in the absence of solvent. After adding the diamine component to the molten dicarboxylic acid component, the melt polymerization is further continued at a temperature equal to or higher than the melting point of polyamide being produced for at least 10 min while maintaining the pressure of the vapor phase in the batch reactor at higher than 0.1 MPaG by introducing water vapor. The polyamide thus produced is hardly affected by gels even when the melt polymerization is conducted in the presence of polyamide remaining after the previous batch production. Molded articles thereof contain little fisheyes.

Abstract: Described is an apparatus for the purpose of drying or solid phase polymerization of Polymer particles by batchwise heating the same in an atmosphere of inert gas or under reduced pressure. More particularly, described is batchwise heating apparatus which is capable of efficient production by preventing an objective product from being contaminated with foreign matters accompanying wear of a sealing packing.

Abstract: In the production method of polyamide of the present invention, the mole balance at a set point during melt polymerization is estimated from a pre-established equation for calculating the mole balance during melt polymerization from a melt viscosity. On the basis of the estimated mole balance, the subsequent conditions of melt polymerization of a batch and the polymerization conditions of the next and subsequent batches are determined. In addition, the mole balance, molecular weight and relative viscosity of melt-polymerized polyamide are estimated from pre-established equations each for respectively calculating the mole balance, molecular weight and relative viscosity at the end point of melt polymerization from the melt viscosity. The conditions for solid phase-polymerizing the melt-polymerized polyamide are determined on the basis of estimated values.

Abstract: In the production method of polyamide of the present invention, the mole balance at a set point during melt polymerization is estimated from a pre-established equation for calculating the mole balance during melt polymerization from a melt viscosity. On the basis of the estimated mole balance, the subsequent conditions of melt polymerization of a batch and the polymerization conditions of the next and subsequent batches are determined. In addition, the mole balance, molecular weight and relative viscosity of melt-polymerized polyamide are estimated from pre-established equations each for respectively calculating the mole balance, molecular weight and relative viscosity at the end point of melt polymerization from the melt viscosity. The conditions for solid phase-polymerizing the melt-polymerized polyamide are determined on the basis of estimated values.

Abstract: The present invention provides an apparatus for the purpose of drying or solid phase polymerization of Polymer particles by batchwise heating the same in an atmosphere of inert gas or under reduced pressure. More particularly, it pertains to batchwise heating apparatus which is capable of efficient production by preventing an objective product from being contaminated with foreign matters accompanying wear of a sealing packing.

Abstract: The polyamide resin of the present invention is produced by the polycondensation of a dicarboxylic acid component and a diamine component containing xylylenediamine and bisaminomethylcyclohexane in a total amount of 70 mol % or higher. The polyamide resin contains impurities having a boiling point of from 150 to 300° C. at ordinary pressure and a solubility parameter of from 8 to 16 in a total amount of 0.3% by weight or lower based on the weight of the polyamide resin. The polyamide resin is free from various inconveniences due to inclusion of the impurities, and suitably used in applications for molding materials, bottles, sheets, films and fibers.

Abstract: In the method for solid-phase drying or solid-phase polymerizing a polyamide of the present invention, the polyamide that is stored for 20 days or longer after the production thereof until subjected to the solid-phase drying or the solid-phase polymerization under the specific conditions is used as the starting material. By storing the polyamide under the specific conditions of the present invention, the resultant solid-phase dried or solid-phase polymerized polyamide with a low yellowness is obtained even if 20 days or more time has lapsed after the starting polyamide is produced until it is subjected to the solid-phase drying or solid-phase polymerization.

Abstract: In the process for producing polyamide of the present invention, a diamine and a dicarboxylic acid are melt-polycondensed in a batch-wise fist polymerizer in the absence of a solvent to produce a middle-stage polyamide. The diamine has a boiling point higher than a melting point of the middle-stage polyamide being produced under inner pressures of the first polymerizer. The middle-stage polyamide is fed into a continuous second polymerizer while controlling the change of relative viscosity within ±0.2, and further polycondensed there to produce the objective polyamide. With such a process, the change of polymerization degree of the middle-stage polyamide during the switching of the polymerization step from a batch-wise manner to a continuous manner is avoided, thereby preventing the variation in quality of the final product.