JPH10237168A - Continuous polycondensation process and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for the continuous polycondensation reaction capable of getting a high polymer in a short time without decreasing the flow rate of the treating liquid (by using in the form of extremely thin-layer) and decreasing the generation of off-specification product in the change-over of the kind of the product, by promoting the evaporation of a volatile substance in the treating object liquid in non-contact state, and to provide an apparatus for the process. SOLUTION: The apparatus main body contains plural cylindrical rotors and a transfer member such as a metal plate extended between the rotors. A treating object liquid is supplied in the form of a film to a surface of the transfer member and an inert gas heated to a prescribed temperature is ejected through a plurality of small nozzles against the surface of the treating liquid during the movement of the liquid in the apparatus main body. The surface of the liquid is renewed by this process to proceed the polycondensation reaction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for forming a high-molecular polymer by a polycondensation reaction or the like. For example, the present invention relates to polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polyamide, polyethylene naphthalate, polybutylene naphthalate, liquid crystal polymer and the like. The present invention relates to a continuous polycondensation reaction method and apparatus suitable for producing a polycondensation polymer. The present invention also relates to a continuous processing method and apparatus suitable for use in removing or dehydrating volatile substances from highly viscous substances.

[0002]

2. Description of the Related Art The prior art is disclosed in JP-A-63-10460.
As described in Japanese Patent Laid-Open Publication No. 2 (1994), two cylindrical rotating bodies are installed in an apparatus body covered with a heat medium jacket, and a conveying member such as a metal plate is stretched over a belt and they are heated by heating. Thus, the liquid to be treated, which is supplied in a thin film form on the surface of the conveying member, is heated to remove volatiles from the surface. Another technique is to remove volatile substances in the polymer by mechanically applying a polymer to the inner wall of the device using a stirrer installed inside the device, like a thin film evaporator. Met.

In the case of producing a polycondensation polymer, a high polymer cannot be obtained unless volatile substances generated during the reaction are removed from the liquid to be treated. In addition, since the liquid to be treated is usually a highly viscous solution, the diffusion rate of volatile substances in the liquid to be treated is much lower than the evaporation rate at the liquid surface, and the concentration of volatile substances in the liquid to be treated is low. In order to reduce this, it is necessary to make the inside of the reactor a high vacuum or to make the thickness of the liquid to be treated extremely small to promote the evaporation of volatile substances.

[0004] However, in the former method of making a high vacuum, the design conditions of the reactor are strict and a vacuum pump for achieving the high vacuum is required, so that the equipment cost increases. In the latter method of reducing the thickness of the liquid to be treated, as described in JP-A-63-104602, the surface of the liquid to be treated which is in contact with the gas phase is replaced (surface renewal).
If the process is not carried out, the progress of the polycondensation reaction will be extremely slow unless the thickness of the liquid to be treated is made extremely thin, so that a long residence time is required to obtain a high polymer. For this reason, in order to increase the throughput per unit time, it is necessary to increase the size of the reactor, resulting in a large equipment cost. In addition, an apparatus and a method such as a thin film evaporator mechanically renew the surface of the liquid to be treated. Inevitably, problems such as deterioration of polymer quality due to incorporation into the material and generation of a large amount of off-specs when switching types are inevitable.

[0005]

SUMMARY OF THE INVENTION According to the present invention, the evaporation of volatile substances in a liquid to be treated is promoted in a non-contact state, so that the flow rate of the liquid to be treated can be reduced without reducing the flow rate (extremely thin). It is an object of the present invention to provide a continuous polycondensation reaction method capable of obtaining a high-polymerized product by using the method and reducing the off-spec generated at the time of switching product types, and an apparatus therefor.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention solves the above problem by moving a transfer member such as a metal plate stretched between a plurality of cylindrical rotors installed in an apparatus body. A liquid to be treated is supplied in a film shape to one surface of the conveying member, and when they move inside the apparatus body, an inert gas heated to a predetermined temperature is sprayed from a plurality of pore nozzles onto the surface of the liquid to be treated. The present invention also provides a continuous polycondensation reaction method and an apparatus for renewing the surface of the liquid to be treated so that the polycondensation reaction proceeds.

According to the continuous polycondensation reaction method and apparatus of the present invention, the surface of the liquid to be treated can be renewed in a non-contact manner by injecting an inert gas at a high speed onto the surface of the liquid to be treated. In addition to the fact that the liquid mass that was present in the liquid comes into contact with the gaseous phase, the evaporation of volatile substances is promoted and the concentration of volatile substances in the liquid to be treated can be reduced. The off-specs generated in the above can be reduced as much as possible.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The polycondensation reaction which is the subject of the present invention includes, for example, polycondensation polymers such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polyamide, polyethylene naphthalate, polybutylene naphthalate, and liquid crystal polymer. Reactions used for production are mentioned. In the present invention, a prepolymer of these polycondensation polymers or a prepolymerized one is used. The viscosity of the polymer used depends on the type of the target polycondensation reaction and the degree of polymerization of the target polymer.
・ S.

According to the present invention, the liquid to be treated is applied to one surface of the transfer member while moving the transfer member formed of a metal plate or the like stretched between a plurality of cylindrical rotors installed in the apparatus main body at a constant speed. Are supplied in the form of a film, and when they move in the apparatus main body, an inert gas heated to a predetermined temperature is jetted at high speed from a plurality of fine nozzles onto the surface of the liquid to be treated, and The surface is renewed and the polycondensation reaction proceeds.

[0010] The material of the transporting member used in the present invention includes metals (for example, stainless steel and aluminum), rubber, and Teflon. As the shape,
A plate shape, a wire mesh shape, and a wire shape are exemplified. In the present invention, the transport member is moved at a constant speed or the like, but the residence time in the apparatus varies depending on the target resin and the like.

Although a plurality of cylindrical rotors are used in the apparatus main body of the present invention, these are installed in, for example, two or more rows in the vertical direction. For example, it is installed at the upper part and the lower part in the apparatus main body. The cylindrical rotor is a rotatable cylindrical member, and examples of its material include metal (for example, stainless steel and aluminum), rubber, and resin. In some cases, the inside of the cylinder is hollow, and a heating medium (a heated gas or a heated liquid) flows through the inside of the cylinder. In the present invention, the cylindrical rotor which is installed in the main body of the apparatus and has the surface of the film-like treatment liquid facing the film-like treatment liquid has a structure capable of maintaining a non-contact state with the film-like treatment liquid. When cylindrical rotors are provided at the upper and lower portions in the apparatus main body, the lower cylindrical rotor comes into contact with the liquid to be treated on the transport member. In this case, if the lower cylindrical rotor can be kept in a non-contact state with the film-like liquid to be treated, the liquid to be treated attached to the cylindrical rotor stays in the apparatus body for a long time and then mixes into the product. There is an advantage that problems such as deterioration of polymer quality and generation of a large amount of off-spec at the time of product change can be avoided. As a structure capable of maintaining a non-contact state with the film-like liquid to be processed, a structure in which wheels are provided at both ends of a rotating shaft connected to a driving device, a wheel shaft-shaped structure in which a concave portion is provided in an outer peripheral portion of a cylindrical rotor, There may be mentioned two rotors in which a central portion of a cylindrical rotor is removed and separated, but preferably a wheel-shaft in which a concave portion is provided in an outer peripheral portion of the cylindrical rotor.

A liquid supply apparatus for supplying a liquid to be treated to one side surface of the conveying member in a film form may be a liquid supply apparatus capable of supplying the liquid to be treated in a fixed amount within a range of 0.5 mm to 5 mm. A slit device and a rod-shaped extrusion device may be used. Here, the slit device means a device in which the shape of the liquid outlet to be treated has an opening having a width of 0.5 to 5 mm.

In the continuous polycondensation reaction method according to the present invention, the thickness of the liquid to be treated supplied onto the transport member is 0.5 mm.
５5 mm, the nozzle cross-sectional average flow rate of the inert gas injected from the pore nozzle to renew the surface of the liquid to be treated is 50 m / s to 400 m / s, and the tip of the pore nozzle and the surface of the liquid to be treated are Is preferably set to 5 mm to 100 mm, and the installation interval of the fine-hole nozzles arranged in a direction perpendicular to the traveling direction of the liquid to be treated is preferably set to 1 mm to 20 mm. With these, it is possible to create an effective surface renewal state according to the viscosity of the liquid to be treated, which rises with the progress of polymerization.

In the continuous polycondensation reaction method according to the present invention, the interior of the apparatus body is set to an inert gas atmosphere such as nitrogen at normal pressure or slightly pressurized state, and an inert gas containing volatile substances generated in the reaction process is used. Is sent to a condenser installed outside the device, cooled, recovers the contained volatile substances, reheated to a predetermined temperature, and sprayed onto the surface of the liquid to be treated from a plurality of pore nozzles installed inside the device main body. It is preferable to circulate in the apparatus main body.

The inert gas used in the present invention refers to nitrogen and a gas belonging to Group 0 of the periodic table. Preferably, it is nitrogen.
By filling with an inert gas, the inside of the apparatus main body is brought to a normal pressure state or a slightly pressurized state. Slightly pressurized state means several mmH ₂
It is in a slightly pressurized state of about O.

The volatile substances generated in the reaction process vary depending on the type of the target polycondensation reaction, and include, for example, water, methanol, ethylene glycol, acetaldehyde and the like.

Although the pore nozzle used in the present invention is not particularly limited, the cross-sectional shape of the tip has a diameter or a long axis of 0.5.
A circular or elliptical shape having a width of ３3 mm or a slit having a cross-sectional shape of a tip having a width of 0.5 to 3 mm is preferable.
The slit shape means a shape having an aspect ratio of 1 or more. The reason why these shapes are used is that there is an advantage that the flow state is controlled in accordance with the degree of polymerization of the liquid to be treated adhered on the member and the surface renewal efficiency is increased.

The inert gas containing volatile substances generated in the reaction process is sent to a condenser installed outside the apparatus to cool and recover the contained volatile substances. It is preferable to spray the liquid to the surface of the liquid to be treated from a plurality of provided fine nozzles so as to circulate the liquid in the apparatus body. Here, the predetermined temperature is basically the reaction temperature of the target polycondensation reaction, and varies widely depending on the target polycondensation reaction. For example, in the production of polyethylene terephthalate, the temperature is in the range of 270 to 320 ° C.

Further, in the continuous polycondensation reaction method according to the present invention, in addition to the above-described structure, a scraping device which is installed outside the apparatus main body and scrapes the liquid to be treated on the conveying member is provided. Thereby, the surface of the transport member is always kept clean.

Further, in the continuous polycondensation reaction method according to the present invention, a heater for preheating the transport member is provided immediately before the entrance of the transport member of the apparatus main body, and the heater is provided immediately after the exit of the transport member of the apparatus main body. It is preferable to provide a cooler for cooling the liquid to be treated. As a result, the liquid to be treated adhering to the transport member coming out of the apparatus main body is rapidly cooled and solidified to facilitate removal from the transport member, and the temperature of the transport member entering the apparatus main body does not interfere with the reaction. Not be kept at a certain temperature.

An example of the continuous polycondensation reaction apparatus according to the present invention is shown in FIG. 1 and the present invention will be described based on the example, but the present invention is not limited thereto. A plurality of cylindrical rotors (2a, 2b) installed at the upper and lower parts in the apparatus main body 1 and a plurality of cylindrical rotors (2c) installed outside the apparatus main body
While the transport member 3 stretched in between is moved at a constant speed by a transport member delivery cylindrical rotor 7 installed outside the apparatus main body, the processing target liquid is supplied to one side of the transport member 3 by the processing liquid supply slit device 4. The film is supplied on the surface. As they move in the apparatus main body 1, an inert gas heated to a predetermined temperature is jetted from a plurality of fine-hole nozzles 15 onto the surface of the liquid to be treated at high speed, and the surface of the liquid to be treated is renewed to cause polycondensation. Allow the reaction to proceed. As shown in an enlarged view of FIG. 2, the cylindrical rotor 2 b installed at the lower portion in the apparatus main body 1 always keeps the non-contact state between the cylindrical rotor 2 b and the liquid to be treated on the transport member 3. Thus, it has a wheel shaft shape with a concave portion provided on the outer peripheral portion. FIG. 3 is an enlarged view of the fine nozzle 15 and the fine nozzle pipe 8 for injecting an inert gas onto the surface of the liquid to be treated.

The inside of the apparatus main body 1 is at normal pressure or several mmH _2.
Under an inert gas atmosphere in a slightly pressurized state of about O,
A gas sealing device 9 is provided at the entrance and exit of the transport member of the apparatus main body, and the state in the apparatus main body is maintained. The inert gas containing a volatile substance generated in the reaction process is sent to a condenser 11 installed outside the apparatus and cooled to collect the volatile substance.
After that, the inert gas is reheated to a predetermined temperature by the heating device 12 through the compressor 14 and the pipe 10, and is injected from the plurality of fine nozzles 15 onto the surface of the liquid to be treated. The scraping device 13 is installed outside the device main body 1,
The liquid to be treated is scraped off. The conveying member heating device 5 is installed immediately before the entrance of the conveying member 3 of the apparatus main body 1 and the conveying member 3
To preheat. The transport member cooling device 6 is installed immediately after the outlet of the transport member 3 of the apparatus main body 1 and cools the liquid to be treated on the transport member 3.

[0023]

EXAMPLES Hereinafter, examples of the polycondensation reaction method according to the present invention will be specifically described with reference to polymerization examples of polyethylene terephthalate. The continuous polycondensation reaction device shown in FIG. 1 was used as the continuous polycondensation reaction device. (Example 1) 350 wtppm of antimony trioxide as a catalyst and 300 wtppm of triphenyl phosphate as a stabilizer were added to a raw material slurry obtained by mixing terephthalic acid and ethylene glycol at a molar ratio of 1.0: 1.5. The esterification reaction was carried out in a two-stage esterification reaction tank at a temperature of 260 ° C. and a residence time of 4.5 hours and 2 hours, respectively, to obtain a prepolymer having a conversion of about 95%. next,
This prepolymer is heated at a temperature of 270 ° C. under a pressure of 1.0 mmHg.
Preliminary polymerization was performed for about 1 hour under the conditions described above, and the intrinsic viscosity of the obtained polymer was measured using a mixed solvent at 20 ° C. in which the weight ratio of phenol and 1,1,2,2-tetrachloroethane was 4 to 6 at 20 ° C. The intrinsic viscosity was 0.60 dl / g when measured using a meter. Next, the polymer was continuously supplied onto the conveying member of the continuous polycondensation reaction apparatus according to the present invention, which was controlled at a temperature of 300 ° C., so as to maintain a thickness of 1.0 mm.
A nitrogen gas heated to a temperature of 300 ° C. was sprayed from the circular nozzle at a flow rate of about 400 m / s to renew the surface, and polymerization was performed for a residence time of 3 minutes. The intrinsic viscosity of the obtained polymer is 0.79
dl / g.

Example 2 The same experiment as in Example 1 was carried out except that the nitrogen gas injection speed was changed to about 170 m / s, to obtain a polymer having an intrinsic viscosity of 0.72 dl / g.

Example 3 The same experiment as in Example 1 was conducted except that the temperature of the inside of the continuous polycondensation reaction apparatus according to the present invention and the temperature of the nitrogen gas injected were changed to 285 ° C.
A polymer having an intrinsic viscosity of 0.71 dl / g was obtained.

[0026]

As described above, according to the continuous polycondensation reaction method and apparatus of the present invention, the surface of the liquid to be treated supplied in the form of a film is treated by an inert gas jetted at a high speed from a fine nozzle. By allowing the polycondensation reaction to proceed while being renewed, the frequency of contact between the liquid to be treated and the inert gas can be increased, and the evaporation of volatile substances generated during the reaction process in the liquid to be treated can be promoted. Time can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view of an example of a continuous polycondensation reaction apparatus according to the present invention.

FIG. 2 is a schematic view of a cylindrical rotor 2b installed inside the apparatus main body in the continuous polycondensation reaction apparatus of FIG.

FIG. 3 shows an example of an arrangement of fine nozzles 15 for ejecting the inert gas of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Apparatus main body 2a Upper cylindrical rotor in apparatus 2b Lower cylindrical rotor in apparatus 2c Outside cylindrical rotor 3 Transport member 4 Supply slit device of liquid to be treated 5 Transport member heating device 6 Liquid cooling device 7 Transport Cylindrical roller for delivering members 8 Piping for fine nozzle 9 Gas sealing device 10 Piping for sending inert gas 11 Condenser 12 Inert gas heating device 13 Scrapping device 14 Compressor 15 Fine nozzle

Claims (6)

[Claims] 1. A liquid to be treated is supplied to one surface of a transport member while moving a transport member stretched between a plurality of cylindrical rotors installed in a main body of the apparatus. When the liquid to be processed moves in the main body of the apparatus, an inert gas heated to a predetermined temperature is jetted from a plurality of pore nozzles onto the surface of the liquid to be processed, and the liquid to be processed is A continuous polycondensation reaction method characterized by renewing the surface of the above to progress the polycondensation reaction. 2. The method according to claim 1, wherein the thickness of the liquid to be treated on the conveying member is 0.5 to 5 mm, and the cross-sectional average flow rate of the inert gas injected from the tip of the fine hole nozzle is 50.
~ 400m / s, the gap between the tip of the pore nozzle and the surface of the film-like treatment liquid is 5 ~ 100mm,
The installation interval of the fine nozzles arranged in a direction perpendicular to the traveling direction of the liquid to be processed is 1 to 20 m.
The continuous polycondensation reaction method according to claim 1, wherein m is m. 3. The inside of the main body of the apparatus is an inert gas atmosphere under normal pressure or slightly pressurized state, and an inert gas containing a volatile substance generated in a reaction process is supplied to a condenser installed outside the apparatus. After feeding and cooling to collect the volatile substance, the volatile substance is reheated to a predetermined temperature and sprayed from a plurality of the fine nozzles onto the surface of the liquid to be processed and circulated in the main body of the apparatus. The continuous polycondensation reaction method according to claim 1 or 2, wherein 4. A plurality of cylindrical rotors installed inside and outside the main body of the apparatus, a transport member stretched between the cylindrical rotors, a driving device for moving the transport member, and the transport moving A heater for preheating the members before entering the apparatus main body, a liquid supply apparatus for supplying the liquid to be processed to the surface of the transport member, and an inert surface for the obtained film-shaped liquid to be processed A plurality of fine-hole nozzles for injecting gas, a cooler for cooling the film-like liquid to be processed after exiting from the main body of the device, and a cooler for discharging the liquid to be processed from the main body of the device. Having a scraping device for scraping after processing, the cylindrical rotor facing the surface of the film-form liquid to be disposed in the main body of the device can be kept in a non-contact state with the film-form liquid. Continuous degeneration characterized by a structure Combined reaction device. 5. The continuous polycondensation reaction apparatus according to claim 4, wherein the cross-sectional shape of the tip of the nozzle is a circle or an ellipse having a diameter or a long axis of 0.5 to 3 mm. 6. The continuous polycondensation reaction apparatus according to claim 4, wherein the cross-sectional shape of the tip of the micropore nozzle is a slit having a width of 0.5 to 3 mm.