JP2006143918A - Method and apparatus for serially producing porus spherical polyamide particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing porus spherical polyamide particles having a uniform particle size in a large scale, able to stably supply the porus particles having the particle size in a specific range, a relative particle size distribution, a small pore size and a specific surface area with high crystallinity in relation to the method and the apparatus for serially producing the porus polyamide particles. <P>SOLUTION: The method for serially producing the porus spherical polyamide particles is to prepare a temporary solution by mixing a solution (A) comprising an aliphatic polyamide and its solvent with an organic nonsolvent (B) of the polyamide and water (C), to precipitate the polymer and obtain the dispersed porus spherical particles, and comprises a specific serial process. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a continuous production method and continuous production apparatus for polyamide porous spherical particles having a specific particle size and pore size, a narrow particle size distribution, a large specific surface area and a high crystallinity.

  As a conventional method for producing a polyamide powder, chemical powdering, mechanical pulverization, direct polymerization and the like are known. Among them, the chemical powder method has been used for a polyamide having functionality because a relatively uniform quality powder can be obtained by selecting a solvent and a non-solvent for the polyamide.

  For example, Wei-Hsin Hou, Thomas B. et al. Lloyd, Applied Polymer Sci. 45, 1783 (1992) discloses a technique relating to the production of polyamide particles composed of particles having a narrow particle size distribution by precipitating polymer crystals from a non-polyamide water from a formic acid solution.

  Patent Documents 1 to 3 disclose a method for producing a porous polyamide suitable for an adsorbent such as polyphenol.

In addition to this, several methods for producing polyamide particles from a solution are disclosed. For example, Patent Document 4 discloses a method for producing a polyamide powder for cosmetics that has a particle size of 20 μm or less by spraying a metacresol solution of nylon 11 or 12 in a molten state and cooling. .

  Furthermore, Patent Document 5 discloses polyamide porous spherical particles having a specific particle size, particle size distribution, specific specific surface area and porosity, and a method for producing the same.

JP 52-43860 A Japanese Patent Laid-Open No. 52-14668 Japanese Patent Laid-Open No. 52-110765 JP-A-5-70598 Japanese Patent Laid-Open No. 2002-80629

  However, mass production with industrialization is difficult with past production methods, and a new production method suitable for mass production has been demanded.

  In mass production of polyamide porous spherical particles of uniform particle size, using a continuous production method and its production equipment, it has a specific range of particle size, relatively particle size distribution, pore size, specific surface area, It is an object of the present invention to provide a production method capable of stably supplying crystalline porous particles.

The present invention, after mixing a solution (A) composed of an aliphatic polyamide and its solvent, an organic non-solvent (B) of polyamide, and water (C) to temporarily form a uniform solution, The present invention relates to a continuous production method of polyamide porous spherical particles characterized by comprising the following four steps in a production method of depositing a polymer to obtain dispersed porous spherical particles.
(1st process) The process which makes the polyamide solution (A) flow by controlling the flow volume continuously, controls the flow of organic non-solvent (B) and water (C) from one side, and joins them .
(2nd process) The process of mixing the mixed liquid made to merge.
(3rd process) The process made into the liquid mixture which precipitated the polyamide particle, without leaving a liquid mixture still or stirring strongly.
(4th process) The process of isolate | separating a polyamide particle and drying and obtaining a polyamide porous particle.

  The above description, wherein the mixed solution forms a uniform solution until the polyamide solution (A), the non-solvent (B), and water (C) are merged and the mixed solution is allowed to stand (second step). The present invention relates to a continuous production method of porous spherical particles.

  An apparatus for controlling the flow rate of the polyamide solution (A), an apparatus for supplying the organic non-solvent (B) and water (C) of the polyamide with a controlled flow rate, and an apparatus for combining and mixing them. The present invention relates to a continuous production apparatus for porous spherical particles, characterized in that it comprises a device for holding or storing the mixed liquid mixture, and comprising a closed system in which these are connected by a tube.

  The device for supplying the polyamide solution with a controlled flow rate comprises a container capable of filling the polyamide solution, a metering pump for supplying the polyamide solution with a controlled flow rate, and a pipe (tube). It relates to a manufacturing apparatus.

  As an apparatus for supplying polyamide organic non-solvent (B) and water (C) with controlled flow rate, a container that can be filled with (B) or (C), a metering pump and pipe that can be supplied with controlled flow rate (pipe) The above-mentioned continuous production apparatus for porous particles, characterized by comprising a tube).

  The apparatus for joining and mixing relates to the above-mentioned continuous production apparatus for porous particles, which is a static mixer or a mixing tank with a stirrer.

The apparatus for holding the mixed liquid mixture is a replaceable receiver capable of receiving the mixed liquid every time, or a receiver array, characterized in that it is a continuous production apparatus for porous particles as described above About.

  The present invention relates to polyamide porous spherical particles having a specific particle size and pore size, a narrow particle size distribution, a large specific surface area and high crystallinity, and a continuous production method and apparatus thereof.

  Examples of the polyamide used in the present invention include various known ones. For example, it can be obtained by ring-opening polymerization of a cyclic amide or polycondensation of a dicarboxylic acid and a diamine. As monomers, polycondensation of amino acids such as crystalline polyamide obtained by ring-opening polymerization of cyclic amides such as ε-caprolactam and ω-laurolactam, ε-aminocaproic acid, ω-aminododecanoic acid, ω-aminoundecanoic acid, etc. Or polycondensation of dicarboxylic acids and derivatives such as oxalic acid, adipic acid, sebacic acid, 1,4-cyclohexyldicarboxylic acid and diamines such as ethylenediamine, hexamethylenediamine, 1,4-cyclohexyldiamine, pentamethylenediamine, decamethylenediamine It is an aliphatic polyamide obtained as described above. A small amount of an aromatic component such as terephthalic acid, isophthalic acid, or m-xylylenediamine may be copolymerized.

  The aliphatic polyamide of the present invention is a crystalline polyamide comprising a homopolymer and a copolymer thereof, or a mixture thereof. Specifically, polyamide 6, polyamide 66, polyamide 610, polyamide 66 / 6T (T represents a terephthalic acid component), and the like. Moreover, the mixture of the said polyamide may be sufficient. Particularly preferred are polyamide 6 and polyamide 66.

  The polyamide of the present invention has a molecular weight of 2,000 to 100,000. Preferably it is 5,000-40,000.

  The polyamide porous particles of the present invention are spherical particles. Preferably at least 90% by weight of the porous particles are spherical particles. More preferred are at least 98% by weight spherical particles. If the spherical particles are less than 90% by weight, the fluidity as a powder material may be inferior.

  As a solvent used for the polyamide solution of the present invention, an aromatic alcohol or formic acid is preferable. Examples of the aromatic alcohol include phenol, m-cresol, p-cresol, o-cresol, m-cresolic acid, and chlorophenol.

The present invention, after mixing a solution (A) composed of an aliphatic polyamide and its solvent, an organic non-solvent (B) of polyamide, and water (C) to temporarily form a uniform solution, The present invention relates to a continuous production method of polyamide porous spherical particles characterized by comprising the following four steps in a production method of depositing a polymer to obtain dispersed porous spherical particles.
(First step) The polyamide solution (A) is caused to flow continuously while controlling the flow rate, and from one side, the flow rates of the organic non-solvent (B) and water (C) are caused to flow to join them.
(Second step) The combined liquid mixture is mixed.
(Third step) The mixed solution is allowed to stand or is not mixed vigorously, but is used as a mixed solution in which polyamide particles are precipitated.
(Fourth step) The polyamide particles are separated and dried to obtain polyamide porous particles.

  It demonstrates according to a continuous manufacturing process. In the first step, the flow rate of the polyamide solution is controlled to flow. From the other side or from the direction parallel to the flow of the polyamide solution, the flow rate of water is controlled by combining the organic non-solvent of the polyamide and the water.

  The polymer solution viscosity in the first step is preferably 0.1 to 80 poise at room temperature. Preferably, 1 to 50 poise is preferable. If the polymer solution viscosity is less than 0.1 poise, the productivity is inferior. If it is higher than 50 poise, control becomes difficult. The polymer concentration is preferably 2 to 30% by weight, more preferably 5 to 20%. When the polymer concentration is less than 2% by weight, the productivity is inferior. On the other hand, if the polymer concentration is larger than 30% by weight, it is difficult to flow and the flow rate is restricted, which is not preferable.

  The organic non-solvent and water may be mixed in advance at a predetermined ratio and flowed as a mixed liquid, or they may flow independently. The organic non-solvent is preferably an aliphatic alcohol, and is preferably an aliphatic alcohol having a boiling point of 100 ° C. or lower such as methanol or ethanol.

As for the ratio of the flow rate ratio of the polyamide solution to the organic non-solvent and water, the total weight ratio of the organic non-solvent (B) and water (C) of the polyamide is preferably larger than the weight ratio of the polyamide solution (A). Moreover, it is preferable that the ratio of water (C) is 2-90 weight% with respect to the sum total of the non-solvent (B) and water (C) of a polyamide.
For example, the ratio of the flow rate ratio of the polyamide solution to the organic non-solvent and water is 100/500/50 to 100/1500/200 parts by weight. The amount is preferably 100/600/80 to 100/800/150 parts by weight.

  In the case of the present invention, in order to join the polyamide solution, the organic non-solvent, and water, it is preferable to join at a high flow rate.

In the second step, the combined liquid mixture is stirred. It is preferable to mix the liquid mixture quickly to form a uniform solution as quickly as possible.
The apparatus for joining a plurality of liquid feeds to form a mixed liquid may be a tank-like container or a tubular container. In the case of a tank-like container, a container with a stirrer is preferable. In the case of a tubular container, a static mixer or a screw type extruder is preferable. A static mixer is particularly preferable. It is important in the present invention to mix quickly to form a uniform solution.

  A static mixer is a mixing device suitable for causing turbulent flow and mixing with two or more fluids. Furthermore, since mixing and transport are performed simultaneously, the continuous mixing apparatus of the present invention is particularly preferable.

  Even if a mixed solution is produced by adding a polyamide solution, organic non-solvent and water to a relatively large batch container with a stirrer, the production method is stable because the addition time is too long. Since it may be difficult to do so, the batch method has limitations in mass production.

  In the third step, the mixed solution is allowed to stand or is not mixed vigorously, but is used as a mixed solution in which polyamide particles are precipitated.

  The mixed liquid is allowed to stand to crystallize the polyamide particles. When crystallizing the polymer particles, it is preferable to reduce the flow, stirring and movement of the solution as much as possible. Until the growth of the polymer is completed, the polymer mixed solution is preferably kept in a slow flow state or a stationary state. When placed in an early fluidized state, the polymer particles do not become spherical particles, but become irregularly shaped particles, fibers or films, and do not become the intended spherical particles.

  The temperature of the polymer mixture is preferably 5 to 60 ° C. More preferably, it is 5-30 degreeC. For example, if it is left as it is at room temperature or at a temperature lower than room temperature, the polymer crystallizes, and the crystallized polymer is deposited. On the other hand, when the temperature is higher than 60 ° C., the shape of the particles is not likely to be spherical, and a part of the particles is lost. It takes about 1 second to 20 minutes until spherical particles are completely formed through a uniform solution.

  In order to ensure that the crystal particles have a uniform size, a receiver that causes crystallization from a uniform polymer mixture is used as a receiving device in order to reduce the linear velocity of the mixture sent by the tube. It is preferable to use a relatively thick tube or a large diameter receiver.

  Further, since the crystallization time is constant so that the growth of the polymer particles is uniform, it is preferable that the exchangeable receiver or the receiver array capable of receiving the mixed solution at regular time intervals. . When crystallization is completed, it is preferable to put it in a large receiver or store it, for example. At the end of the third step, polymer particles are precipitated in the mixed solution.

In the fourth step, the polyamide particles are separated and dried to obtain polyamide porous particles. When the crystallization is sufficiently complete, the polymer particles are isolated once the particles have precipitated. The isolation method may be any of decantation, filtration, centrifugation, decanter and the like. Simultaneously with the isolation, it is preferred to wash the solvent of the polyamide solution.
For washing, a low boiling point solvent such as aliphatic alcohol or ketone is preferable. It is preferred to repeat the isolation and washing. In order to increase the cleaning efficiency, it is preferable to boil and wash at the boiling point of the solvent.

  Further, after the cleaning, the particles may be subjected to a surface treatment. The surface treatment makes it easy to handle the powder. Moreover, particle | grains can be functionalized by performing a surface treatment.

  The method for drying the washed particles is not particularly limited, but a method that does not disturb the structure of the porous particles is preferable. For drying the polyamide porous particles, for example, hot air drying, air flow drying, spray drying, reduced pressure drying and the like are preferable.

  It is important that the drying temperature does not exceed the melting point of the polyamide. Preferably, it is about 50 to 140 ° C. lower than the melting point.

  The present invention combines a device for supplying a polyamide solution (A) with a controlled flow rate, a device for supplying polyamide non-solvent (B) and water (C) with a controlled flow rate, and mixing them together. The present invention relates to an apparatus for continuously producing porous spherical particles, characterized in that the apparatus comprises a device for holding and storing a mixed liquid mixture, and these are connected by a tube.

  The continuous apparatus for porous particles of the present invention will be described with reference to FIG. The present invention is not limited to that shown in the figures.

  The apparatus for controlling and supplying the flow rate of the polyamide solution is characterized by comprising a container that can be filled with the polyamide solution, a metering pump that supplies the polyamide solution with a controlled flow rate, and a pipe.

  From the polyamide solution tank 1, a predetermined amount is flowed quantitatively by a metering pump 2 and supplied from a pipe. The metering pump 2 needs to control a high-viscosity liquid and feed it quantitatively, and a gear pump, a diaphragm pump, a plunger pump, a syringe pump, and the like are preferable. In order to monitor the flow rate, a flow rate monitor 3 and a pressure gauge 4 may be provided. In addition, it is preferable to provide a backflow prevention valve 6 in order to prevent the liquid feed from flowing back.

  In the present invention, as an apparatus for supplying polyamide organic non-solvent (B) and water (C) by controlling the flow rate, a container that can be filled with (B) or (C) and a fixed amount that can be supplied by controlling the flow rate. It consists of a pump and a pipe (pipe).

  On the other hand, a normal metering pump may be used as the pump for controlling the flow rate of the organic non-solvent or water. However, those capable of controlling a high flow rate are preferable. For example, a rotary pump and a diaphragm pump are preferable. In the case of FIG. 1, a predetermined amount of an organic non-solvent and water are mixed and stored in the non-solvent tank 19, and the flow rate is monitored by the rotary pump 16 using the flow rate monitor 15. In addition, when two or more liquid feeds are joined, it is preferable to provide a backflow prevention valve 13 in each transport pipe in order to prevent interference between the liquid feed amounts.

  In order to merge the polymer solution, the organic non-solvent, and the water solution, the polymer solution that has been quantitatively delivered and the mixed solution of the organic non-solvent and water that has been quantitatively delivered are joined by the junction tube 8. . It is convenient to use a pipe that is thinner than the one for sending the liquid with the smaller flow rate. The mixed solution joined by the joining pipe 8 is further uniformly mixed in the next third step.

  In the present invention, as a device for further mixing the mixed liquid mixture, there is a static mixer 10-1, a mixing tank 10-2 with a stirrer, a static mixer, an in-line mixer, etc. The static mixer 10-1 or the mixing tank 10-2 with a stirrer is preferable. Here, it is preferable to mix quickly and uniformly. When mixing slowly, phase separation has priority, and it does not become a uniform solution. The flow rate is important.

  A small flow rate is not preferable because sufficient mixing cannot be performed. A flow rate above a certain level is required. For example, the Reynolds number is preferably 20 to 1000. In order to obtain a sufficient mixing state, it is necessary to optimize the length of the static mixer, the number of elements, and the like.

  In the mixing apparatus of the present invention, the mixed solution is preferably a uniform solution. When the liquid mixture becomes non-uniform in the mixing device and the polymer begins to precipitate, the particles begin to crystallize, and during crystal growth, the solution is mixed more than necessary and becomes irregular, not spherical. Sometimes inconvenient.

  In the third step, the apparatus for holding the mixed liquid mixture is a replaceable receiver 12 or a receiver row that can receive the mixed liquid every time. It is necessary to receive the mixed solution at regular intervals, hold it until the particles have crystallized from the solution, and leave the particles until the growth of the particles is completed. Then, it is necessary to keep the particles until they are uniform and to stand until the growth of the particles is completed. Then, it is necessary to keep the particles until they are uniform and to stand until the growth of the particles is completed. Then, it is necessary to keep the particles until they are uniform and to stand until the growth of the particles is completed. Then, the particles grow uniformly and have a narrow particle size distribution.

  As a continuous production apparatus, it is preferable to include a flow rate adjusting bypass line, a valve, or the like as necessary.

  As for the manufacturing method of the polyamide porous spherical particle of this invention, 5-60 degreeC is preferable for temperature.

In the fourth step, the polyamide particles are separated and dried to obtain polyamide porous particles. As the apparatus, hot air drying, air flow drying, spray drying, reduced pressure drying and the like are preferable.
It is preferable that the drying temperature does not exceed the melting point of the polyamide. It is preferably about 50 to 140 ° C. lower than the melting point.

The properties of the porous spherical particles that can be produced in the present invention include a number average particle size of 1 to 30 μm, a particle size distribution index of 1.0 to 1.5, an average pore size of 0.02 to 1 μm, and a specific surface area of 100 to 80, 000 m ² / kg, porosity 5-30.

  Thereafter, surface treatment or the like may be performed if necessary to add the functionality of the particles or to facilitate handling.

It may be blended with other powders. Other inorganic particles such as polymer particles, glass particles, and metal particles may be added. It is also used for functional particles such as carriers such as enzymes and catalysts, toners, and dyes. In addition, it can be used as functional particles in cosmetics, electronic materials, industrial products, and medical fields.

Example 1
Polyamide porous particles were produced using an apparatus whose conceptual diagram is shown in FIG. A 5% polyamide m-cresol solution was quantitatively supplied using the diaphragm pump 2 at a flow rate of 100 g / min. On the other hand, 5 parts by weight of methanol and 1 part by weight of water were mixed, and a flow rate of 660 g / min was quantitatively supplied from the non-solvent tank 19 of FIG. The sample was collected for 20 minutes in the mixed solution receiver 12 which was merged by the merge tube 8 and mixed by the static mixer 10-1, and the uniform transparent liquid came out to the valve | bulb 11. FIG. A sample of 15.2 kg (amount of polymer particles 100 g) of the mixed solution was collected, and the precipitated particles were filtered under reduced pressure, washed and dried. The structure of the polymer particles, the particle size and the particle size distribution were observed with a scanning electron microscope. In addition, a BET specific surface area, an average pore diameter by a mercury porosimeter, and the like were measured.

The measurement result was dispersed porous spherical particles. The number average particle size was 9.3 μm, the volume average size was 10.8 μm, the particle size distribution index was 1.15, the specific surface area was 13100 m ² / kg, the average pore size was 0.1 μm, and the porosity was 23.1. It was.

(Example 2)
In Example 1, a sample of the mixed solution was taken in a sampling tube for 6 seconds, and the particle size and particle size distribution were measured. As a result, the number average particle size was 7.5 μm, the volume average particle size was 7.7 μm, and the particle size distribution index was 1.04.

(Example 3)
In Example 1, the liquid mixture was sampled in a receiver row that was collected in a sampling time of 1 minute and stored in the receiver 12 for 20 minutes. The particle size of this sample was measured. As a result, the number average particle size was 7.6 μm, the volume average particle size was 8.0 μm, and the particle size distribution index was 1.05.

  By using the receiver row, porous particles having a relatively narrow particle size distribution can be obtained.

(Comparative example)
A 200 liter polyamide solution tank is charged with 20 kg of 5 wt% polyamide 6, m-cresol solution, and a mixed solution of 120 kg of methanol water (5/1 part by weight) in 24 minutes at a temperature of 24 ° C. in 5 minutes. Added with stirring. During the addition of the mixture, the solution was cloudy. After completion of the addition, stirring was stopped after 1 minute and the mixture was allowed to stand. After 2 hours, the precipitation was completed, and the precipitate was filtered and washed by centrifugation. A polymer sample was taken and the structure was evaluated and measured. As a result, amorphous porous film-like particles were aggregated, and were not dispersed porous spherical particles.

FIG. 1 is a conceptual diagram of the continuous production apparatus of the present invention. FIG. 2 is an example of a mixing device in the continuous device of the present invention. FIG. 3 is an example of a mixing device in the continuous device of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Polymer solution tank 2 Metering pump 3 Flow rate monitor 4 Pressure gauge 5 Valve 6, 7 Backflow prevention valve 8 Merge pipe 9 Pressure gauge 10 Mixing device
11 Valve 12 Mixed liquid tank 13 Valve 14 Valve 15 Flow rate monitor 16 Metering pump 17 Valve 18 Valve 19 Non-solvent tank 20 To filtration device

Claims (7)

By mixing a solution (A) composed of an aliphatic polyamide and its solvent, an organic non-solvent (B) of polyamide, and water (C), a uniform solution is temporarily formed, and then a polymer is precipitated. A method for continuously producing polyamide porous spherical particles, comprising the following four steps in a production method for obtaining dispersed porous spherical particles.
(1st process) The process which makes the polyamide solution (A) flow by controlling the flow volume continuously, controls the flow of organic non-solvent (B) and water (C) from one side, and joins them .
(2nd process) The process of mixing the mixed liquid made to merge.
(3rd process) The process made into the liquid mixture which precipitated the polyamide particle, without leaving a liquid mixture still or stirring strongly.
(4th process) The process of isolate | separating a polyamide particle and drying and obtaining a polyamide porous particle.   The mixed solution forms a uniform solution until the polyamide solution (A), the non-solvent (B), and water (C) are merged and the mixed solution is allowed to stand (second step). 2. A method for continuously producing porous spherical particles according to 1.   An apparatus for controlling the flow rate of the polyamide solution (A), an apparatus for supplying the organic non-solvent (B) and water (C) of the polyamide with a controlled flow rate, and an apparatus for combining and mixing them. An apparatus for continuously producing porous spherical particles, comprising an apparatus for holding or storing the mixed liquid mixture, and comprising a closed system in which these are connected by a tube.   4. The porous particle according to claim 3, wherein the device for supplying the polyamide solution with a controlled flow rate comprises a container capable of filling the polyamide solution, a metering pump for supplying the polyamide solution with a controlled flow rate, and a pipe. Continuous manufacturing equipment.   As an apparatus for supplying polyamide organic non-solvent (B) and water (C) with controlled flow rate, a container that can be filled with (B) or (C), a metering pump and pipe that can be supplied with controlled flow rate (pipe) The continuous production apparatus for porous particles according to claim 3, wherein the apparatus comprises a tube.   The apparatus for continuously producing porous particles according to claim 3, wherein the apparatus for mixing and mixing is a static mixer or a mixing tank with a stirrer.   The device for holding the mixed liquid mixture is a replaceable receiver capable of receiving the mixed liquid every time, or a receiver array, wherein the porous particles are continuous. Manufacturing equipment.

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