Mitsubishi Gas Chemical Company, Inc.

Kazumi Tanaka

Shuta Kihara

Katsumi Shinohara

Hideyuki Kurose

Takatoshi Shida

Minoru Kikuchi

Masahiro Harada

Kazuhiko Amakawa

Toshiaki Nishimura

Kiichiro Seki

Hiroyuki Gonoi

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.

Polyamide resin composition

A solid xylylenediamine solidified in a container is extremely excellent in storage stability as compared with a liquid xylylenediamine, and is less degraded by discoloration even when stored in an atmosphere containing oxygen. By charging a liquid xylylenediamine into a container, solidifying the liquid xylylenediamine into a solid xylylenediamine in the container under cooling without delay after the charging, and storing the solid xylylenediamine in the container while maintaining the xylylenediamine in a solid state, the xylylenediamine is stored for a long period of time without causing deterioration of quality such as discoloration.

Method for storing xylylenediamine

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. The batchwise heating apparatus, which heats Polymer particles in a rotating hermetically sealed vessel in an atmosphere of inert gas or under reduced pressure, comprises a vessel equipped with a temperature detection portion capable of measuring temperature even during rotating and a suction/exhaust port inside the vessel capable of reducing pressure and/or replacing with inert gas even during rotating; and a suction/exhaust pipe that is inserted into the vessel so as to communicate with the suction/exhaust port, wherein the rotational sealing portion of the suction/exhaust pipe is installed on the outside of the vessel.

Batchwise heating apparatus and method of drying a polyamide

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.

Production method of polyamide

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&deg; 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.

Polyamide resins and process for producing the same

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.

Solid-phase drying and solid-phase polymerization of polyamide

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 &plusmn;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.

Process for production of polyamide

In the production of polyamide by the melt-polymerization of the present invention, the polymerization conditions are rapidly and accurately controlled by a near-infrared spectroscopy to enable the efficient production of a desired polyamide with a good stability in its quality.

In the process of the present invention, a recovered polyamide is used as a part of the raw materials for producing polyamide. By carrying out the polycondensation under a condition such that the recovered polyamide is dissolved in the reaction system during the polycondensation, the properties of the polyamide being produced are not deteriorated as compared with those of polyamide which is produced without using the recovered polyamide. By changing the addition amount of the recovered polyamide, the crystallization speed of the resultant polyamide is controlled or increased as compared when produced without using the recovered polyamide.

Process for producing polyamide

The improved polyamide production method of the present invention is characterized by including a step of accurately regulating the molar balance between a diamine component and a dicarboxylic acid component to a desired balance in a batch-wise regulation tank, thereby preparing a slurry liquid substantially free from the amidation reaction. The slurry liquid thus prepared is fed to a batch-wise or continuous polymerization reactor, where the amidation reaction is proceeded to easily produce polyamide having a desired balance of the diamine component and the dicarboxylic acid component without causing a problem such as foaming, solidification, etc.

A solid phase-polymerized polyamide produced by solid phase polymerization of a melt-polymerized polyamide which has a specific relative viscosity and end group balance and is obtained by polycondensing a diamine component mainly comprising m-xylylenediamine with a dicarboxylic acid component mainly comprising adipic acid in molten state. The solid phase-polymerized polyamide is a medium to high viscosity polymer having a specific relationship between the relative viscosity and the number average molecular weight. With such particular properties, the solid phase-polymerized polyamide contains gels and fish eyes in extremely small amounts, and is suitable as a material particularly for producing bottle, sheet, film and fiber.

Solid phase-polymerized polyamide polymer

Disclosed are a resin composition for inhibiting polymerization of a vinyl compound, which includes a resin and 0.1 to 30% by weight based on the resin, of a polymerization inhibitor for the vinyl compound; a resin molding for inhibiting polymerization of a vinyl compound, and a packing for inhibiting polymerization of a vinyl compound in a distillation tower, the resin molding and packing each including this resin composition. Also disclosed are methods for inhibiting polymerization of a vinyl compound, which include contacting the vinyl compound with the resin composition; these methods include processes of inhibiting polymerization of a vinyl compound in a distillation tower, by contacting the vinyl compound in the distillation tower with packing therein which includes this resin composition. By using the resin composition as a construction material of an inner wall of a reactor, distillation equipment and piping and as packing in the distillation tower, to inhibit polymerization of the vinyl compound, the vinyl compound can be produced stably by adding a small amount of the polymerization inhibitor for the vinyl compound without adding a large amount thereof.

Resin composition resin molding and method for inhibiting polymerization of vinyl compound

There are disclosed a method for drying and a method for solid-phase polymerizing a crystallizable polyamide being in an amorphous state which comprises regulating the moisture concentration in the polyamide at its glass transition temperature to at least 0.15% by weight as determined by Karl Fisher titration; heating the polyamide thus regulated at a pressure of at least one arm without reducing the moisture to crystallize the same up to a crystallinity of at least 15% and; further heating the polyamide thus crystallized at a temperature lower than its melting point under reduced pressure with a batchwise heating apparatus. It is made possible according to the method for drying or the method for solid-phase polymerizing the crystallizable polyamide to effect its crystallization without causing tackified sticking or solidified sticking of the polyamide, along with drying or solid-phase polymerization with single apparatus and process, while dispensing with any pretreatment such as surface modification and preliminary treatment equipment intended for crystallization.

Method for drying polyamide and method for solid-phase polymerization of

An oxygen scavenging composition comprising an intimate mixture of (A) a compound having a skeleton of the following formula (1), ##STR1## wherein R is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, m is an integer of 3 to 5, and n is an integer of 1 to 3, provided that m+n equals 6, (B) a transition metal compound and (C) a phosphorus compound. This composition is useful in a variety of fields requiring prevention of rust formation on metal, prevention of oxidation and decay of an organic substance, preservation of foods, prevention of insects and prevention of mold.

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Niigata, Japan

Kazumi Tanaka