Patent application number | Description | Published |
20080262193 | PRODUCTION METHOD OF POLYAMIDE - 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. | 10-23-2008 |
20090295016 | PROCESS AND APPARATUS FOR PRODUCING THERMOPLASTIC RESIN PELLETS - 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. | 12-03-2009 |
20090299027 | PROCESS FOR PRODUCING POLYAMIDE - 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 member and the rotating shaft are disposed above the liquid surface of the melted polymer; and stirring is conducted in a manner such that the circumferential speed of the stirring rods is 30 m/minute or greater. | 12-03-2009 |
20090299028 | PROCESS FOR PRODUCING POLYAMIDE - 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. | 12-03-2009 |
20100120961 | POLYAMIDE RESIN COMPOSITION - A polyamide resin composition comprising a polyamide (X) having a diamine constituent unit which is mainly composed of a m-xylylenediamine unit and a dicarboxylic acid constituent unit which is mainly composed of an adipic acid unit; and specific amounts of a phosphorus acid antioxidant and alkaline component. The polyamide (X) is characterized by a specific range of terminal-group concentration balance and a specific amino-group reaction rate. This composition can simultaneously achieve inhabitation of yellow discoloration and reduction of number of gels or fish eyes. | 05-13-2010 |
20120201917 | APPARATUS FOR PRODUCING THERMOPLASTIC RESIN PELLETS - 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. | 08-09-2012 |
20120271031 | PROCESS FOR PRODUCTION OF POLYAMIDE - 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. | 10-25-2012 |