JPS61166833A - Condensation of nylon - Google Patents

Abstract

PURPOSE:To carry out the continuous condensation of nylon with a compact- sized apparatus, by supplying nylon oligomer continuously to an extruder having two or more openings on the barrel other than the feeding port and extrusion port, and extruding the product continuously at a high temperature while removing water from the openings. CONSTITUTION:A nylon 12 oligomer is produced by carrying out the continuous hydrolytic polymerization of laurolactam under a condition falling within a specific range shown in the figure taking the heating temperature as ordinate and the amount of added water as abscissa. The nylon 12 oligomer or its mixture with a copolymerizable compound (e.g. polyester oligomer) is supplied continuously to an extruder having >=2, preferably >=3 openings on the barrel other than the feeding port and extrusion port, preferably to a twin-screw extruder, and extruded continuously while keeping the main part of the barrel to 280-350 deg.C, passing nitrogen to the opening preferably near to the feeding port, evacuating the die-side opening, and removing water from the openings. Condensation of nylon can be carried out by this process.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for continuous condensation of nylon, and more particularly to a method for continuously condensing nylon 12-based oligomers to obtain a nylon 12-based high polymer.

[Conventional technology]

High-molecular nylons or copolymers such as nylon 6, nylon 6.6, and nylon 12 are produced by adding water to their monomers and polymerizing them at high temperatures and high pressures. After obtaining these oligomers, water is removed. It is obtained by removing the oligomer and condensing the oligomer.

As a method for industrially producing these polymeric nylons or copolymers, there are two methods: a punch method in which a series of these reactions is carried out in one reactor, or a continuous method in which a series of reactions are carried out in a VK tube. method is used.

However, batch methods generally require longer reactions;
The operation is complicated and the productivity is poor. On the other hand, in the continuous method using a VK tube, the internal volume is extremely large and the replacement of the contents is difficult, making it impossible to manufacture a wide variety of products in small quantities.

[Problem that the invention seeks to solve]

The purpose of the present invention is to provide a method for producing high-molecular nylon or copolymers, in which the step of condensing nylon oligomers can be carried out continuously using equipment compact enough to enable production of a wide variety of products in small quantities. be. In particular, by the method described below, a nylon 12-based oligomer that is continuously obtained from a compact facility is introduced into the compact facility together with a compound that can be copolymerized alone or therewith, and continuously condensed. Polymer nylon 12
Another object of the present invention is to provide a method for continuously polymerizing a copolymer using compact equipment.

[Means for solving problems]

The present inventors have found that nylon 12-based oligomers, in particular, polymerize extremely quickly at high temperatures if water is efficiently removed, leading to the present invention. That is, in the present invention, a nylon oligomer or a compound copolymerizable with the nylon oligomer is continuously supplied to an extruder having two or more openings in the barrel in addition to the supply port and the discharge port. This relates to a method for condensing nylon, which is characterized by maintaining the temperature of the part at 280° C. to 350° C. and continuously extruding while removing water from the opening.

According to the present invention, it is possible to continuously condense and polymerize nylon oligomers using general and compact equipment without using equipment with a complicated structure or large-scale equipment. Regarding polymers, by continuously using both the nylon oligomer production method described below and the nylon condensation method of the present invention, it is possible to produce a wide variety of products in small quantities from monomers such as lauryllactam. Nylon polymers and copolymers can be obtained very easily using compact equipment.

The extruder used in the nylon condensation method of the present invention is preferably of a type that can reliably feed the nylon oligomer or a mixture of the nylon oligomer and a compound copolymerizable with it forward as the screw rotates, and in particular a twin-screw extruder or A special screw extruder having comparable performance is most preferably used, and examples thereof include ZSK manufactured by Unirna AG in West Germany and Co-kneader manufactured by Buss AG in Switzerland. Additionally, in addition to the supply and discharge ports, the extruder barrel must have two or more openings to remove moisture generated as the nylon oligomer condenses.
It is more preferable to have the above opening. Each opening is maintained under pressure, normal pressure, or reduced pressure, and preferably prevents oxygen from entering in order to prevent discoloration and deterioration.

Most preferably, the openings near the extruder inlet are flushed with nitrogen to remove moisture, and the die openings are vacuumed to remove moisture.

A condensation catalyst can be injected into the extruder together with or separately from the nylon oligomer, and examples of the catalyst include phosphoric acid and diptyltin oxide.

If the temperature of the extruder is 280° C. or lower, the polymerization rate will be slow, the residence time in the extruder will be long, and the amount of condensation throughput will be reduced, which is not economical. Moreover, if the temperature is 350° C. or higher, thermal decomposition may occur.

When the heating zone of the barrel is divided into multiple sections,
It is sufficient that the main portion thereof is at 280°C to 350°C; for example, even if the heating zone closest to the oligomer supply port or the heating zone closest to the die is below 280°C, it does not depart from the spirit of the present invention. .

The nylon oligomer referred to in the present invention refers to a nylon polymer whose degree of polymerization is so low that it cannot be preferably used as a molded article, and which is capable of further condensation, and specifically, nylon 6
．． 6.6.11.12.6.12 etc.

In the present invention, copolymerizable compounds that can be supplied together with nylon oligomers include other types of nylon oligomers, polyester oligomers, polyether oligomers, and various condensable monomers, such as polytetramethylene glycol, polyester oligomers, etc. Examples include caprolactone and aminoundecanoic acid.

These compounds can be premixed with the nylon oligomer or fed separately to the extruder.

Nylon oligomers and compounds copolymerizable with them are
It is fed to the extruder in a solid or liquid state, optionally at an elevated temperature, preferably in a fixed amount per hour.

[Manufacture of nylon oligomer]

The present inventors have invented a new method for producing nylon oligomers, particularly nylon 12 oligomers, used in the nylon condensation method according to the present invention, which will be described below.

That is, the present invention provides a method for producing oligomers by continuous hydrolytic polymerization of lauryllactam.

Nylon 12 is produced from lauryllactam by ring-opening polymerization, and in particular, when the polymer is obtained on an industrial scale, a hydrolysis polymerization method is used as the ring-opening polymerization method.

Hydrolytic polymerization of lauryllactam is a method of adding water to lauryllactam and raising the temperature to obtain nylon 12 oligomer. As is well known, in the subsequent process water is removed from this oligomer and it is converted into a condensation polymer to become nylon 12 (
(See Special Publication No. 42-6512).

However, the hydrolysis polymerization rate of lauryl lactam is extremely slow, and is about 1710 to 1730 times the hydrolysis polymerization rate of caprolactam, which is a monomer of nylon 6. For this reason, high temperature and high pressure conditions are used, but the reaction time still takes a long time.

For example, the temperature is 280°C to 290°C, the amount of added moisture is 2 to 5%,
Under conditions of pressure 15-30 kg/cn+", 5-30 kg/cn+"
Requires a reaction time of 15 hours. For this reason, even a batch polymerization method using an autoclave requires large-scale high-pressure equipment, and a continuous polymerization method requires an even larger-scale and more complicated high-pressure equipment.

It is also estimated that the hydrolytic polymerization rate of lauryllactam will further increase by increasing the temperature and the amount of water added, but increasing the temperature and the amount of water added will increase the pressure during polymerization. Extremely, for example 100 kg/
It is estimated that the increase will be more than cm2. For this reason,
It was thought that such conditions could not be achieved industrially due to the limits of the pressure resistance of polymerization containers, and conventionally attention was focused on how to make polymerization possible under low pressure conditions.1
It was

An object of the present invention is to provide a method for producing oligomers by continuously hydrolyzing and polymerizing lauryllactam in a short reaction time using small-scale equipment.

For this purpose, the present inventors changed their thinking and conceived the idea of carrying out hydrolysis polymerization of lauryllactam under extremely high temperature and pressure, and arrived at the present invention.

In other words, the relationship between heating temperature and added water content is shown on a graph with heating temperature on the vertical axis and added water content on the horizontal axis (370°C, 2%
), (340℃, 3%), (325℃, 10%),
(310℃, 20%)1. (300℃, 30%), (
The object of the present invention is achieved by continuously hydrolyzing and polymerizing lauryllactam within the range surrounded by the lines connecting the points 295°C, 50%) and (360°C, 40%). It was found that That is, it has been found that when hydrolysis polymerization is carried out under such conditions, the reaction time can be shortened to within 30 minutes. In batch polymerization, the monomer charging time, temperature raising time, product removal time, etc. are long, so shortening the polymerization time may not have much meaning, but in continuous polymerization, ,
Residence time at high temperature and high pressure is reliably shortened to less than 30 minutes, reducing the capacity of the high temperature and high pressure container used.
Not only can the entire device be downsized, but a small-capacity high-temperature, high-pressure container can be manufactured extremely easily. In other words, this method combines the hydrolytic polymerization of lauryl lactam in an extremely short time under high temperature and high pressure with the continuous polymerization method. Thus, a method for continuous production of lactam oligomers is provided.

The range of heating temperature and amount of added water used in this method is specifically the range shown in FIG. The amount of water added herein refers to the amount of water expressed in weight % relative to the polymerization of the entire polymerization system including lauryllactam, copolymerizable monomers, and additives.

If the temperature is lower than the range shown in FIG. 2, the polymerization rate will be slow; if the temperature is higher than the range shown in FIG. 2, problems such as coloring and formation of by-products will occur. Moreover, if the water content is less than the range shown in FIG. 2, the polymerization rate will be slow, whereas if it is too much, the pressure will become unnecessarily high, and the degree of polymerization of the obtained oligomer will be extremely reduced.

As a continuous polymerization device used to carry out this method, it is desirable to use a tubular container connected to a heating device, such as a heat exchange coil, as shown in the production example below, and heated by a high-pressure pump. Lauryllactam and water are fed into the tubular container through the device and polymerization takes place.

The gist of this invention is to continuously polymerize lauryl lactam, which has a slow hydrolysis polymerization rate, using simple equipment. A copolymer oligomer can be obtained by hydrolytic copolymerization by a method. Furthermore, as long as the monomer is copolymerizable, it can be copolymerized not only with polyamide monomers but also with polyester monomers. For example, terpolymers of lauryllactam, caprolactam and adipic acid hexamethylene diamine salt useful as hot melt adhesives may also be suitably polymerized. Furthermore, additives such as a polymerization degree regulator, a polymerization accelerator, and a stabilizer can be added in addition to the monomer.

The nylon 12 oligomer or copolymerized oligomer obtained by the method of this invention usually has a number average molecular weight Mn of 700 to 700.
4000 and heat condensation under reduced pressure, normal pressure, or increased pressure to obtain high molecular weight nylon 12 or copolymer. As the condensation method for this nylon, it is most preferable to apply the condensation method using the extruder of the present invention as described above, but conventionally known condensation methods can also be used.

In this case, the condensation conditions are such that the condensation is carried out at a temperature of 250 to 350° C. for 2 minutes to 5 hours in a nitrogen stream at normal pressure or reduced pressure. Continuous condensation can also be carried out by moving the oligomer at a constant speed while stirring.

Next, an example of producing nylon 12 oligomer by the method of the present invention will be shown.

Production Examples 1 to 4 Nylon 12 oligomers were produced using the apparatus shown in FIG.

In Figure 3, ■ indicates that the lower part of the heater 1a is
It is a silo heated to ℃ and contains lauryl lactam. This silo is filled with lauryllactam and then replaced with nitrogen, with a small amount of nitrogen constantly flowing to prevent air from entering the silo.

The lauryl lactam is melted in the lower part of this silo, and is fed under pressure into a flexible pipe 6 by a high-pressure pump 2.

The corrugated tube 6 is immersed in a night bath 7 which is kept at a constant temperature and stirred, and has an inner diameter of 10 nφ.

It is made of stainless steel with an outer diameter of 12IllIφ and a length of 30 fins.

3 is a silo with a steam pipe 3a at the bottom, which contains pure water and is in a boiling state. The boiling pure water is fed under constant pressure to a flexible pipe 5 in a night bath 7 by a high-pressure pump 4. The serpentine pipe 5 has an inner diameter of 6Hφ.

It is made of stainless steel with an outer diameter of 8flφ and a length of 5II+. The pure water is heated through a flexible tube 5, and then sent to a flexible tube 6 where it is mixed with lauryllactam.

The mixture of lauryl lactam and water, which has been heated in a corrugated tube 6 and partially polymerized, is heated to a constant temperature by a band heater 88 from the outside and has an inner diameter of about 50 wφ.

The reaction tube 8 is made of stainless steel and has an outer diameter of about 60 nφ and a length of 51 I+. The reaction tube 8 had a total of 10 Melplenders (static mixers) manufactured by Sulzer Co., Ltd. at intervals of about 50 am inside.

The mixture of oligomer and water polymerized in the reaction tube 8 is flushed through a relief valve 9 that opens when the pressure exceeds 150 kg, and is sent to the cyclone 10. Cyclone 10
The heated steam is separated from the upper part and the molten oligomer is separated from the lower part, and the oligomer is cooled and solidified in the cooling water tank 11.

Using this apparatus, various oligomers were produced by changing the flow rate of the lauryl lactam pressure pump 2, the flow rate of the pure water pressure pump 4, the temperature of the night bath 7, and the temperature of the reaction tube 8, as shown in Table 1.

After drying, the solidified oligomer was subjected to Soxhlet extraction with acetone for 24 hours, and the amount of acetone extracted was measured. This corresponds to the amount of residual monomer. Further, the moisture content of the dried oligomer was measured at 250° C. using a coulometric titration moisture meter manufactured by Mitsubishi Kasei Corporation to determine the approximate condensed moisture content. The larger this value is, the lower the degree of polymerization of the oligomer is. The results are shown in Table-1.

The oligomer obtained in Production Example 1 was heated at 25% in a nitrogen stream.
After heating at 0° C. for 2.5 hours, a nylon 12 polymer was obtained. The obtained nylon 12 polymer was heated at 25°C and 0.5°C.
It had a degree of polymerization with a relative viscosity of 1.72 in a 5% edge cresol solution.

Table 1 Production Example 5 A 44.4% caprolactam aqueous solution was placed in the hot water bath of 3 instead of pure water, and a copolymerized oligomer of lauryllactam and caprolactam was polymerized in the same manner as in Production Examples 1 to 4. However, the amount of lauryl lactam pumped is 12.8 kg/hr.
, 44.4% caprolactam aqueous solution pressure amount is 7.2
kg/hr, the night bath temperature was 345°C, and the reaction tube temperature was 340 t.

The polymerization ratio of lauryl lactam and caprolactam is 80/2
0, the amount of added water corresponds to 20%, and the residence time is 2
The duration is 0 to 22 minutes.

The residual monomer I of the obtained oligomer was 1.5%, which was mostly caprolactam. The condensed water content was 1.05%. When this polymer is heated at 240°C for 5 hours in a nitrogen stream, a copolymer is obtained, and the relative viscosity in a 0.5% cresol solution at 25°C is 1.70. The melting point is 1
The temperature was 50°C.

〔Example〕

Next, an example of a method for obtaining high molecular weight nylon or copolymer from nylon oligomer by the nylon condensation method according to the present invention will be shown.

Embodiment 1 From the raw material supply port 15 as shown in FIG. The second opening in the 17.24x length to the 27x length position on the barrel the third
A twin-screw extruder (Z manufactured by Werner) having an opening 18
S K 53 L/D=42) was used in the experiment.

The screw was designed for long retention time. barrel 3
The temperature at zero was 300°C over the entire area. At the feed port 15 of this extruder, a compound having a molecular weight of about 20 ppm containing 70 ppIN of phosphoric acid was added.
00 (measured by end group titration), liquid nylon 12 oligomer at 200° C., was fed at a constant rate of 50 kg for 1 hour. The screw rotation speed was set to 6 Orpm, nitrogen was flowed through the first opening and the second opening, and the third opening was vacuumed to remove moisture accompanying condensation.

Cooling the strand discharged from the discharge port 20 of the die,
Upon cutting, a milky white pellet was obtained.

When the relative viscosity of this pellet was measured with a 0.5% m-cresol solution at 25°C, the relative viscosity was 1.95, indicating that it was a polymeric nylon 12 suitable for injection molding, extrusion molding, etc.

Example 2 Into the feed port 15 of the extruder used in Example I, 110 parts of phosphoric acid with a number average molecular weight of 1000, obtained by polymerizing 85.7 parts by weight of lauryl lactam and 14.3 parts by weight of dodecanedioic acid, was added.
Nylon 12 oligomer, which is liquid at 200°C and contains 0 pp, is supplied at a constant rate of 35 kg for 1 hour, and at the same time, 15 kg of bis(3-aminopropyl) polytetrahydrofuran (manufactured by BASF) having a number average molecular weight of about 750 is supplied for 1 hour. It was supplied at a constant rate of . The temperature of the barrel is 29 over the entire area.
The temperature was 0° C., and the screw rotation speed was 6 Orpm. As in Example 1, nitrogen was flowed through the first and second openings, and the third opening was vacuumed to remove moisture accompanying condensation.

The strand discharged from the goo was cooled and cut to obtain a milky white pellet. This pellet was heated to 25℃, 0.5
% m-cresol solution, the relative viscosity was 1.89, and it was a flexible nylon 12-based elastomer suitable for injection molding and extrusion molding.

[Brief explanation of the drawing]

FIG. 1 is a schematic longitudinal cross-sectional view of an extruder used in the condensation reaction of nylon oligomers of the present invention. Figure 2 shows nylon 12
FIG. 3 is a diagram showing the relationship between the heating temperature and the amount of added water in the production of oligomers, and is a schematic diagram of the apparatus used in the production of nylon 12 oligomers. 1 is a silo, 2 is a high-pressure pump, 3 is a hot water tank, 4 is a high-pressure pump, 5 is a serpentine pipe, 6 is a serpentine pipe, 7 is a night bath, 8 is a reaction tube, 9 is a relief valve, 10 is a cyclone, 11 is a cooling water tank , 15 is the supply port, 16° 17, 18 is the barrel opening, 20 is the discharge port, 30 is the barrel Applicant Kaoru Furuya Figure 1

Claims (1)

[Claims] A nylon oligomer or a nylon oligomer and a compound copolymerizable therewith are continuously supplied to an extruder having a barrel having two or more openings in addition to the supply port and the discharge port, and the temperature of the main parts of the barrel is controlled. A method for condensing nylon, which comprises maintaining the temperature at 280°C to 350°C and continuously extruding while removing water from an opening.