JPH0432096B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a continuous polymerization method and apparatus for 12-aminododecanoic acid, and more specifically, to a continuous polymerization method and apparatus for 12-aminododecanoic acid.
The present invention relates to a continuous polymerization method and apparatus for continuously producing nylon-12 having a high molecular weight and high quality using aminododecanoic acid as a monomer raw material.

(Prior Art) Nylon-12 has conventionally been produced by heating and polymerizing dodecalactam (laurinlactam) or 12-aminododecanoic acid. 12 of these
- In the method using aminododecanoic acid as a monomer raw material, water is produced as a by-product due to the condensation of amino groups and carboxy groups.

When 12-aminododecanoic acid is continuously polymerized by heating, the reaction water creates a pressurized state in the lower part of the polymerization tank, and the polycondensation reaction proceeds only up to a certain degree of polymerization.

Therefore, in order to obtain nylon-12 with a high degree of polymerization from 12-aminododecanoic acid, it is necessary to use a two-stage polymerization method of prepolymerization and postpolymerization.

In the conventional two-stage polymerization method, 12-aminododecanoic acid is heated and melted in a polymerization container to perform preliminary polymerization.
Next, in the same polymerization vessel, the mixture is heated to a higher temperature under normal pressure or reduced pressure to perform post-polymerization to increase the degree of polymerization.

(Problems to be Solved by the Invention) The conventional two-stage polymerization method is a discontinuous method and has the problem of low productivity.Furthermore, even after the post-polymerization is completed and the produced polymer is released, the walls of the polymerization container A part of the produced polymer adheres and remains, and when the prepolymerization and postpolymerization are repeated, the residual polymer deteriorates due to thermal history.
It has the disadvantage of reducing the quality of the final polymer product. To avoid this drawback, regular cleaning of the polymerization vessel is required, which significantly reduces productivity.

12-Highly polymerized nylon from aminododecanoic acid-
The most problematic point in producing nylon-12 is the removal of by-product water from the polycondensation system.
As the polycondensation progresses, the melt viscosity of this system increases, making it difficult to remove by-product water.

Therefore, the object of the present invention is to effectively remove water by-produced in the polycondensation process of 12-aminododecanoic acid,
This results in a high polymerization degree and high quality nylon.
An object of the present invention is to provide a method and apparatus for continuous polymerization of 12-aminododecanoic acid, which enables the continuous production of 12-aminododecanoic acid.

Another object of the present invention is that during the continuous two-stage polymerization of 12-aminododecanoic acid, post-polymerization is progressing.
To provide a polymerization method and apparatus in which water can be efficiently removed from a 12-aminododecanoic acid polymer without interfering with the smooth movement of the polymer from a low polymerization degree region to a high polymerization degree region. be.

(Means for Solving the Problems) According to the present invention, a first step of continuously supplying 12-aminododecanoic acid to a vertical first polymerization tank and prepolymerizing it; The molten prepolymerization product is supplied from one end to a horizontal second polymerization tank that has a head space at the top and is equipped with a stirring mechanism that rotates around a horizontal axis, and the water in the molten polymer is removed from the head space. Continuous polymerization of 12-aminododecanoic acid, characterized in that it consists of a second step of post-polymerizing the molten polymer while volatilizing it, and continuously taking out high molecular weight nylon-12 from the other end of the second polymerization tank. A method is provided.

According to the present invention, the upper part has a 12-aminododecanoic acid supply port and the exhaust port, the lower part has a prepolymerization product discharge port, a stirrer is provided inside, and a heating jacket is provided on the outer peripheral wall. a vertical first polymerization tank; having a pre-melted polymerization product supply port at one horizontal end and a high molecular weight nylon-12 discharge port at the other horizontal end; The container comprises a housing part, a head space thereon, a stirring mechanism for the molten polymer which can rotate about an axis extending substantially horizontally, and an inert gas supply port communicating with one end of the head space in the tank. a horizontal second polymerization tank having an inert gas and moisture outlet communicating with the other end of the head space and a heating jacket on the outer peripheral wall; a prepolymerization product outlet of the first polymerization tank; A continuous polymerization apparatus for 12-aminododecanoic acid is provided, comprising: a pump and a pipe for transferring the prepolymerization product, which are connected to the prepolymerization product supply port of the second polymerization tank. .

(Function) In the present invention, the polymerization of 12-aminododecanoic acid is carried out continuously in two steps: prepolymerization in the first polymerization tank and postpolymerization in the second polymerization tank. A horizontal polymerization tank equipped with a head space at the top and a stirring mechanism rotating around a horizontal axis is used as the polymerization tank, and the molten prepolymerization product is supplied from one end of this horizontal polymerization tank, and the prepolymerization product is supplied from the other end. A distinctive feature is the removal of high molecular weight final polymerization products.

First, by using a horizontal polymerization tank as the second polymerization tank, all areas from the pre-polymerization product supply area (low polymerization degree area) to the final polymerization product take-out area (high polymerization degree area) of this polymerization tank are It becomes possible to form a head space, and it becomes possible to secure a sufficiently large evaporation area of reaction water.

In addition, by providing a stirring mechanism that rotates around a horizontal axis in the horizontal polymerization tank, the molten polymerization product at the bottom of the polymerization tank is forcibly stirred upward toward the head space, and the melt and gas phase are mixed. The constant renewal of the contact interface significantly accelerates the evaporation of the reaction water contained in the molten polymerization product. At this time, if dry nitrogen gas or the like is flowed into the head space above the molten polymerization product phase, or if the pressure is maintained at reduced pressure, the water pressure in the head space will be reduced and water evaporation will be carried out more efficiently. Become.

Furthermore, the stirring of the molten polymerization product phase is performed from the bottom → top →
Since it is carried out only in the vertical direction of the bottom, it is possible to secure the residence time necessary for the completion of polymerization in the second polymerization tank, and the amount of molten polymerization product is equivalent to the amount of prepolymerization product supplied from one end of the polymerization tank. A certain amount of the final polymerization product is discharged from the other end of the polymerization tank due to the self-flowing properties of the polymer itself, and the polymerization product is smoothly transferred from the low polymerization degree area to the high polymerization degree area without back mixing. It turns out. As already pointed out, generally speaking, the higher the degree of polymerization of nylon-12, the more viscous the melt becomes, making it difficult to remove water from it. However, according to the present invention, the aforementioned head space can be reduced. The combination of the installation and the use of a horizontal stirring mechanism also facilitates the evaporative removal of water from the highly polymerized melt.

The polymer that has reached the desired molecular weight is taken out from the second polymerization tank through a discharge device, taken out in the form of a sheet, film, or string by other known methods, cooled and solidified, or further processed as necessary. cut into small pieces.

Any type of polymerization tank can be used as the first polymerization tank, but it is not suitable for the purpose of uniformly diffusing and dispersing powdered 12-aminododecanoic acid in the polymerization tank, heating and melting it, and polymerizing it. A vertical polymerization tank, in particular, has a supply port for the monomer raw material and an exhaust port for moisture at the top, a prepolymerization product discharge port at the bottom, a stirrer inside, and a heating device on the outer peripheral wall. It is preferable to use a vertical polymerization tank with a jacket for the polymerization.

The prepolymerization product is transferred from the first polymerization tank to the second polymerization tank via a pump and piping.

(Preferred embodiment of the invention) The invention will now be described with reference to the accompanying drawings.

FIG. 1 is a longitudinal cross-sectional view of an example of the continuous polymerization apparatus of the present invention used to carry out the continuous polymerization method of the present invention, and FIG. 2 is a cross-sectional view taken along the line A-A in FIG. , FIG. 3 is a sectional view taken along the line B--B in FIG. 1.

1, 2, and 3, a monomer supply port 2 and an exhaust port 3 are provided at the top of a vertical first polymerization tank 1, and a prepolymerization product discharge port 4 is provided at the bottom. A heating medium supply port 5' is provided on the outer peripheral side wall.
and a heating jacket 5 equipped with a heating medium supply port 5''
is provided. A heater 6 is provided slightly above the center of the interior of the first polymerization tank 1, and the heater 6 is arranged concentrically with the vertical central axis of the first polymerization tank 1 as its axis. In addition, there are heat medium flow passages 7 inside the four pieces.
A cylindrical heating plate 8 with It is composed of three heat medium discharge pipes 10 for discharging the connected heat medium. At the upper part of the heater 6, a stirring arm 13 arranged horizontally, and a rotating stirring blade 11 located between each heating plate 8 and between the heater 6 and the inner wall of the first polymerization tank 1 are provided. A rotary stirrer 12 having a rotary agitator 12 is provided and is adapted to be rotated by a motor _M1 . At the upper part of the monomer supply port 2, there is provided a monomer measuring feeder 14, an inert gas supply pipe 15 connected to the monomer outlet of the monomer measuring feeder 14, and the other end of the inert gas supply pipe 15. An inert gas metering feeder 16 is provided, which is connected to the monomer supply port 2 by a monomer supply pipe 17 .

The second polymerization tank 30 has a generally cylindrical shape and is arranged horizontally, and includes a storage section 31 for the molten polymer, a head space 32 above it, and a shaft extending substantially horizontally. A stirring mechanism 34 for stirring the molten polymer is provided which can rotate around a rotation axis 33. The shaft 33 of the stirring mechanism 34 is driven and rotated by a motor _M2 .

A supply port 35 for the pre-polymerized product in a molten state is provided below one lateral end of the polymerization tank 30, the left end in this specific example, and a supply port 35 for the prepolymerized product in a molten state is provided at the other lateral end of the tank, in this specific example the right end. A discharge port 36 for the final polymerized product, that is, highly polymerized nylon-12, is provided below one end.

The polymerization tank 30 also has a supply port 37 for inert gas such as N ₂ that communicates with one end of the head space 32 in the tank, and a supply port 37 for inert gas and evaporated water that communicates with the other end of the head space 32. A discharge port 38 is provided. Further, the outer peripheral wall 39 of the second polymerization tank is provided with a heating jacket 40 for heating the prepolymerization product in the tank to a high temperature to continue the postpolymerization.

A discharge pipe 41 of nylon-12 is provided at the discharge port 36 of high molecular weight nylon-12, and this discharge pipe 41
A conveyance screw 42 driven by a motor _M3 is installed inside the system to take out the final product, nylon-12, out of the system.

The stirring mechanism 34 may be any mechanism as long as it can stir the molten polymer in the tank without leaving a dead space, and is equipped with a stirring blade 43 that has multiple shafts such as a single shaft or two shafts and moves close to the bottom wall of the tank. Something is desirable.

The prepolymerization product outlet 4 of the first polymerization tank 1 and the prepolymerization product supply port 35 of the second polymerization tank 30 are connected by a polymer transfer pipe 20 and a gear pump 21 driven by a motor _M4 . ing. A heating jacket 22 is provided around the polymer transfer tube 20 and gear pump 21 to maintain the polymer in a molten state.

During polymerization, powdered 12-aminododecanoic acid raw material ADA is passed through pipe 18 to metering feeder 1.
4 and metered at a predetermined supply rate, the monomer ADA is discharged into a monomer supply pipe 15. on the other hand,
An inert gas such as N ₂ passes through a pipe 19, is adjusted to a predetermined flow rate by an inert gas metering feeder 16, and is sent into the monomer supply pipe 15 through a supply pipe 15. The monomer ADA and the inert gas _N2 are mixed in the monomer supply pipe 15, and the monomer ADA is carried by the inert gas flow as a carrier gas to the monomer supply port 1.
2 into the first polymerization tank 1. The monomer ADA supplied into the tank is transferred to the arm 13 of the stirrer 12.
The particles are uniformly diffused and dispersed by the blades 11 over the entire surface of the molten liquid in the polymerization tank 1.

By supplying a heating medium to the heating jacket 5 through the heating medium supply port 5', the entire first polymerization tank 1 is heated to a predetermined temperature, and a plurality of concentrically arranged heating mediums are heated through the heating medium supply pipe 9. The heating plate 8 is also heated to a predetermined temperature.

The powdered monomer is heated and melted by heat conduction from each heating plate 8, and polycondensation is started. The reaction water produced by polycondensation rises in the molten phase, reaches the top of the polymerization tank, and is discharged to the outside of the tank through the exhaust port 3 accompanied by the inert gas. Meanwhile, the melt reaches the bottom of the polymerization tank while undergoing a polycondensation reaction.

Prepolymerization of 12-aminododecanoic acid is carried out at 180°C or higher;
Particularly preferred is a polymerization temperature of 180 to 260°C and 1.5
It is preferable to carry out the reaction under a pressure of at most atmospheric pressure (absolute), preferably 1.0 to 1.5 atm (absolute). The polymerization time required for prepolymerization is generally 3 to 10 hours. The degree of polymerization of nylon-12 in the prepolymerization is such that the relative viscosity (ηrel) is less than 2.0 and the number average molecular weight is generally 5,000 to 20,000.

In addition, in this specification, relative viscosity (ηrel) is
It refers to something measured using the following method.

Relative viscosity measurement method (based on JIS K 6810) (1) Sample (prepolymerized product or nylon 12) approx.
Accurately weigh 250mg to 0.1mg and transfer to a 100ml stoppered flask.

(2) Next, add 98% sulfuric acid to a concentration of 1g/100ml.

(3) Add a rotor and stir using a magnetic stirrer for at least 4 hours to completely dissolve.

(4) After 6 hours, remove 15 ml of the solution using a whole pipette and transfer to a Canon Fuenske viscometer.

(5) Place in a constant temperature water bath adjusted to 25±0.05℃ and leave for 30 minutes.

(6) Measure the number of seconds required for the flow to flow between the upper and lower marked lines of the viscosity tube three times with a stopwatch, and take the average value.

(7) Similarly, measure the number of seconds required for the solvent sulfuric acid.

(8) Calculate the relative viscosity using the following formula.

Relative viscosity = Number of seconds for sample solution to flow down / Number of seconds for 98% sulfuric acid to flow down In addition, inert gas such as _N2 is 0.003 to 0.02N
It is preferable to supply the monomer raw material at a flow rate of m ³ /Kg and discharge it together with the reaction water. The dimensions of the first polymerization tank are not particularly limited, but the ratio of height to inner diameter is preferably in the range of 2:1 to 5:1.

The prepolymerization product that has reached the bottom of the first polymerization tank 1 is extracted from the outlet 4 in a molten state, and is transferred to the second polymerization tank 30 via the transfer pipe 20 by the gear pump 21.
It is supplied into the second combination tank 30 through a supply port 35 provided at the bottom of one end. The second combination tank 30 is heated by the heating medium supplied into the heating jacket 40.
The polymerization temperature is maintained at a predetermined polymerization temperature higher than that of the first polymerization tank 1.

The prepolymerization product supplied into the second polymerization tank 30 is heated to the above temperature, and is lifted upward by the rotation of the stirring blade 43 attached to the rotating shaft 33 along the bottom wall of the tank, and the prepolymerization product is heated to the above temperature. A contact interface with space 32 is reached. As a result, the reaction water produced by the subsequent polycondensation evaporates into the head space 32, is accompanied by the inert gas supplied into the head space 32 through the supply port 37, and is then evaporated into the discharge port 3.
8 and is discharged outside the tank. As water in the melt phase is removed during polycondensation, postpolymerization of the molten nylon-12 proceeds easily. Nylon-12
The melt is transferred from the bottom of the second polymerization tank to head space 3.
2, the water in the system is removed and the post-polymerization progresses by repeating the vertical movement of the polymer. Due to its nature, it is sent in the horizontal direction of the tank, ie, laterally towards the outlet 36. The post-polymerization product is discharged to the outside of the tank through the discharge port 36.

The postpolymerization of the prepolymerization product is carried out at a higher temperature than the prepolymerization temperature and generally from 200 to 360°C, especially from 230 to 280°C.
It is preferable to carry out the reaction at a temperature of .degree. C. and under normal pressure to reduced pressure. The polymerization time required for the post-polymerization is generally 2 to 8 hours, and a highly polymerized nylon-12 having a number average molecular weight of 14,000 to 39,000 is generally obtained by the post-polymerization. Inert gas such as nitrogen gas supplied 0.03
A range up to m ³ /Kg raw material is suitable. It is to be understood that the removal of moisture from the headspace is preferably accomplished by passing dry inert gas through the headspace, but may also be accomplished by vacuum degassing.

As the stirring blades 43 in the second combination tank 30,
Any type may be used as long as it has wings that rotate and move along the bottom wall 39, such as a control type, a tapered roll type, a screw thread type, a spiral tube type, and a disc type. Among these, preferred is a shape that prevents back mixing of the molten polymer as much as possible.

The stirring mechanism that can be used in the second polymerization tank of the present invention includes two parallel stirring blades, and the nylon-12 melt is moved through the center of the tank to the interface with the head space, Mention may be made of the stirring type, which then moves through the sides of the tank to the bottom of the tank. FIG. 4 shows this type of stirring mechanism, in which two stirring shafts 33a and 33b are arranged in parallel with an interval in the lateral direction in the second combination tank 30, and stirring blades are mounted on each stirring shaft. 43a and 43b are provided. The shaft 33a is rotated clockwise and the shaft 33b is rotated counterclockwise, and the stirring blades 43a and 43b are provided so as to be out of phase by 90 degrees. Thus, the shaft 33a (or 33b)
It is clear that the nylon-12 melt is lifted into the head space four times for each rotation of the It will be appreciated that it can be easily removed.

(Effects of the Invention) According to the present invention, the polymerization of 12-aminododecanoic acid is carried out in two stages: prepolymerization in a first polymerization tank and postpolymerization in a horizontal second polymerization tank. During post-polymerization in a polymerization tank, the pre-polymerized product is Even when the polymer is an extremely viscous melt, water produced as a by-product of polycondensation is effectively volatilized and removed in the head space, making it possible to produce nylon-12 with a high degree of polymerization.

In addition, the prepolymerized product of 12-aminododecanoic acid obtained in the first polymerization tank is continuously taken out and supplied to one end of the horizontal polymerization tank, and the final polymer is fed from the other end due to the self-flowing properties of the polymer itself. This method has the advantage that the polymerization product can be smoothly transferred from the low polymerization area to the high polymerization degree area without back mixing.

(Examples) Example 1 Using a 12-aminododecanoic acid continuous polymerization apparatus as shown in FIG. 1, 12-aminododecanoic acid was continuously polymerized.

The first polymerization tank 1 has an inner diameter of 1.15 m, an inner height of 3.8 m, an inner volume of 2.9 ^m3 , and a heating plate 8.
The thickness of is 0.5cm, the vertical width is 50cm,
The stirring blades 11 were comb-shaped, and the length of the portion overlapping the heating plate was 25 cm.

The inner diameter of the second mixing tank 30 was 0.61 m, the inner length was 1.75 m, and the stirrer had 20 glasses-shaped stirring blades.

While maintaining the contents of the first polymerization tank at a volume of approximately 1.9 m ³ with the liquid level approximately 10 cm above the upper end of the heating plate, the heating jacket and heating plate were heated to a temperature of approximately 230°C. Circulate the OIL and turn on the stirrer
Rotated at 6r.pm.

Powdered 12-aminodocanoic acid is supplied from the monomer supply port 2 at a rate of 250 kg per hour.
The first polymerization tank was continuously charged with 2Nm ³ of nitrogen gas. The temperature of the gas phase of the first polymerization tank is 190℃.
The pressure is 10mmH ₂ O G, and the temperature of the liquid phase (contents) is 210℃ at the top, 230℃ at the center, and 240℃ at the bottom.
maintained. 12-aminododecanoic acid was polycondensed so that the residence time in the first polymerization tank was about 18 hours, and by adjusting the rotation speed of the gear pump 21 from the prepolymerization product outlet, 250 kg per hour was produced.
The prepolymerized product was taken out at a rate of .

The number average molecular weight of the prepolymerization product is 10000 (relative viscosity
1.67), water content was 0.4% by weight, and melting point was 176°C.

The pre-polymerization product was supplied to the second polymerization tank 30 via the transfer pipe 20 at the same rate of 250 kg/hr as described above. While continuously discharging nylon-12 from the nylon-12 discharge port 41, the amount of polymer in the second polymerization tank is maintained at approximately 830 kg, and a head space 3 is provided at the top.
Adjustments were made so that 2.

A heating medium was passed through the heating jacket 40 to adjust the temperature of the polymer in the second polymerization tank to 255°C. Without closing the inert gas supply port 37 and supplying inert gas, the pressure in the gas phase of the second polymerization tank is maintained at normal pressure while removing water vapor produced by the polymerization reaction from the exhaust port 38. maintained.

The stirring shaft 33 was rotated at 8 r.p.m.

The nylon-12 taken out from the nylon-12 discharge port 41 by the screw extractor 42 has a number average molecular weight of 15600 (relative viscosity 1.95), a terminal amino group of 1.54×10 ^-5 eq/g, and a terminal carboxyl group. is 11.26
×10 ^-5 eq/g, and the melting point was 177°C.

It was possible to operate stably and continuously for 180 days under the above conditions.

Example 2 By adjusting the rotation speed of the gear pump 21, the supply rate of the prepolymerization product was adjusted to 140 kg per hour.
(the supply rate of 12-aminododecanoic acid was also changed), and nitrogen gas was added at 3N from the inert gas supply port 37.
Example 1 except that the polymer was supplied to the second polymerization tank at a rate of m ³ /hr and the temperature of the polymer in the second polymerization tank was changed to 265°C.
12-aminododecanoic acid was continuously polymerized in the same manner as described above.

The nylon-12 obtained from the second polymerization tank has a number average molecular weight of 37900 (relative viscosity 3.20), a terminal amino group of 2.20×10 ^-5 eq/g, and a terminal carboxyl group of 3.07.
×10 ^-5 eq/g, and the melting point was 178°C.

It was possible to operate stably and continuously for 180 days under the above conditions.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of an example of the continuous polymerization apparatus of the present invention used to carry out the continuous polymerization method of the present invention, and FIG. 2 is a cross-sectional view taken along the line A-A in FIG. FIG. 3 is a sectional view taken along the line BB in FIG. 1, and FIG. 4 is a sectional view of another preferred example of the second combination tank. 1 is a first polymerization tank, 2 is a monomer supply port, 3 is an exhaust port, 4 is a prepolymerization product discharge port, 5 is a heating jacket, 6 is a heater, 7 is a heat medium flow path, and 8 is a heating plate, 9 is a heat medium supply pipe, 10 is a heat medium discharge pipe, 11 is a stirring blade, 12 is a rotary stirrer, 13 is a stirring arm, 14 is a monomer metering feeder, 15 is an inert gas supply pipe, 16 is a inert gas metering feeder,
17 is a monomer supply pipe, 20 is a polymer transfer pipe, 21
is a gear pump, 22 is a heating jacket, 30
is the second polymerization tank, 31 is the molten polymer, 32 is the head space, 34 is the stirrer, 35 is the prepolymerization product supply port, 36 is the nylon-12 discharge port, 37 is the inert gas supply port, and 38 is the exhaust port. 40 is a heating jacket, and 41 is a screw extractor.

Claims (1)

[Scope of Claims] 1. A first step of continuously supplying 12-aminododecanoic acid to a first vertical polymerization tank for prepolymerization;
The molten prepolymerization product obtained in the process is fed from one end to a horizontal second polymerization tank that has a head space at the top and is equipped with a stirring mechanism that rotates around a horizontal axis. Post-polymerization of the molten polymer is carried out while the moisture is evaporated into the head space, and high molecular weight nylon-12 is added from the other end of the second polymerization tank.
1. A continuous polymerization method for 12-aminododecanoic acid, comprising a second step of continuously taking out 12-aminododecanoic acid. 2. The method according to claim 1, wherein the prepolymerization is carried out at a temperature of 180 to 260°C and the postpolymerization is carried out at a temperature of 200 to 360°C. 3 Prepolymerization at a concentration of 1 g/100 ml in 98% sulfuric acid
The method according to claim 1, wherein the relative viscosity of nylon-12 measured at 25°C is less than 2.0, and the post-polymerization is carried out such that the relative viscosity of nylon-12 is higher than that of the pre-polymerization. Method. 4 Vertical type 1 having a 12-aminododecanoic acid supply port and an exhaust port at the top, a prepolymerization product discharge port at the bottom, a stirrer inside, and a heating jacket on the outer peripheral wall. Polymerization tank: It has a pre-melted polymerization product supply port at one lateral end, a high molecular weight nylon-12 discharge port at the other lateral end, and has a molten polymer storage section inside and above it. A headspace and a stirring mechanism for the molten polymer that can rotate about an axis extending substantially horizontally, an inert gas supply port communicating with one end of the headspace in the tank and the other end of the headspace. a horizontal second polymerization tank having an inert gas and moisture outlet communicating with the first polymerization tank and a heating jacket on the outer peripheral wall; a pump and a pipe for transferring the prepolymerization product connected to the prepolymerization product supply port; 12
- Continuous polymerization equipment for aminododecanoic acid.