JPS585204B2 - Polyamide polyamide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a copolyamide by reacting two or more types of polyamides.

It is known that when different polyamides are heated and melted at the same time, the polyamides progress over time to a block copolymer and then to a random copolymer due to an amidation exchange reaction.

However, this transamidation reaction is very slow even under stirring, probably due to the slow motion of the molecular chains of the polymer, and it only proceeds at such high temperatures that the polyamide starting material is partially damaged by heat.

Therefore, the resulting copolyamide is significantly thermally damaged and contains gelled substances, coloration, or an abnormal imbalance of terminal amino groups and terminal carboxyl groups.

The purpose of the present invention is to avoid causing the above-mentioned thermal damage.
An object of the present invention is to provide a method for copolymerizing two or more types of polyamides.

Furthermore, it is an object of the present invention to provide a method for obtaining sufficiently randomly copolymerized polyamides as polymers without any thermal damage.

The static melt mixer referred to in the present invention is a pipe that has no moving parts and is equipped with several elements having a dividing function.

Specific examples of static melt mixers include those shown in FIGS. 1 and 2, for example.

In Fig. 1, 1 is the pipe body, 2 and 3 are elements having clockwise and counterclockwise spiral rotation, respectively, and 4 is
It is a heating element using heat or a heating medium such as Dowsum or Etsotherm.

Further, in FIG. 2, 1 is a pipe body, and 2 and 3 are elements, respectively.

The element is V-cut so that both ends cross each other, and four flow channels run through the center line of the cut in a spiral shape so that they do not overlap in the middle. A tetrahedral space is created at the junction of elements 2 and 3, where the outlet arrangement is orthogonal, and the fluid polymer is divided into four layers in each element.

4 in the figure is a heating body. When a molten polymer is sent through such a pipe, layer division by the element, layer conversion from the center of the pipe to the pipe wall based on spiral rotation,
Furthermore, the fluid polymer is mixed very uniformly by layer inversion based on right and left rotation.

However, the greatest feature of the present invention is that the mixer is used as a reactor for copolymerization of completely pure molten polyamide.

That is, when the two types of molten polyamides are subjected to a copolymerization reaction in the mixer, only the copolymerization reaction proceeds extremely favorably without causing almost any thermal damage such as gelation or decomposition to the molten polyamides. It became possible to use it.

The two or more types of polyamides referred to in the present invention refer to thermoplastic synthetic polyamides, such as nylon 6, nylon 66, nylon 610, nylon 612, nylon 11, nylon 12 and copolymers thereof, hexamethylene diamine. and isophthalic acid or terephthalic acid, or a binary or tertiary copolymer of the above-mentioned nylon and a polymer consisting of para- and meta-xylene diamine and adipic acid or sebacic acid.

In the present invention, the combination of polyamides used as starting materials is appropriately selected depending on the intended use of the resulting copolyamide.

There are various methods of supplying two or more selected polyamides to a static melt mixer, such as a method of quantitatively supplying each polyamide already in a molten state using a gear pump, or a method of supplying two or more types of polyamide chips to a static melt mixer. A method is suitable for the present invention, in which the components are mixed in advance, then melted using a screw extruder or melting grid, and then fed to a static melt mixer.

In particular, a method in which two or more types of polyamides are dynamically melt-mixed in advance by screw mixing or stirring blade mixing, etc., and then fed to a static melt mixer is a method that produces fully randomly copolymerized polyamides, that is, monomers. This method is one of the most suitable methods for the present invention, as it allows a polymer having almost similar physical properties to a copolyamide of the same composition obtained by polymerization from , without any thermal damage.

The static melt mixer used in the present invention may be of the type shown in Figure 1, Figure 2, or any other type.

Further, it is generally preferable that the number of elements filled in the pipe be as large as possible.

However, increasing the number of sheets without limit is disadvantageous in terms of equipment.

However, the present invention can be fully implemented as long as the lower limit of the number of elements is satisfied.

Generally, the degree of mixing based on the splitting effect of a static melt mixer is given by the following equation.

(Here, D is the inner diameter of the pipe, A is the element 1 used
For example, in the element shown in Figure 1, A=
2. In the element of FIG. 2, A=4.

n is the total number of elements filled in the pipe, and d is the width of the dividing layer of the polymer after passing through the n-th element.

) In order to suppress thermal damage to a minimum and to allow the copolymerization reaction to proceed conveniently, the divided layer width d is adjusted to be 10 μm or less, preferably 1 μm or less.

That is, if the type and number of elements are selected so that the dividing layer width d is 10μ or less, especially 1μ or less,
The invention can be successfully implemented.

The copolymerization reaction temperature is appropriately selected within a temperature range in which the starting polyamide melts and the starting polyamide and the resulting copolyamide do not undergo thermal decomposition.

An advantage of the reaction temperature settings of the present invention is that the reaction can be carried out at considerably higher temperatures.

That is, since the static melt mixer used in the present invention mixes the fluid polymer extremely uniformly by layer division, layer switching, and further layer inversion, local abnormal heating due to external heating can be almost completely eliminated.

Therefore, it is also possible to proceed with the copolymerization reaction by heating from the outside at a fairly high temperature.

Further, the copolymerization reaction time can be appropriately selected depending on the copolymerization rate of the polymer to be obtained.

In carrying out the present invention, for example, when a block copolymer is to be obtained, 10 to 30 minutes is appropriate.

On the other hand, when a random copolymer is to be obtained, a reaction time of 60 minutes or more is appropriate.

The greatest advantage of the present invention is that even if the reaction time is set to 60 minutes or more to obtain a random copolymer, a polymer with almost no thermal damage can be obtained. In order to complete the polymerization reaction, it is also possible to provide a maturing section after the static melt mixer. For example, as shown in the examples, nylon 6, nylon 66 and nylon 6
When 12 is reacted, a random copolymer having almost the same polymer physical properties as a polymer having the same composition obtained by monomer polymerization is obtained.

According to the present invention, copolymers made of two or more types of polyamides, such as nylon 6, nylon 66, nylon 612, etc., and having various composition ratios depending on the purpose of use, as well as block or random copolymers, etc. It is possible to produce a polymer having copolymerization dust of

Furthermore, since the present invention only quantitatively supplies pre-molten polyamide to a static melt mixer and reacts therein, copolyamide can be produced continuously, which is efficient in terms of equipment and economy. This is an extremely advantageous method for producing copolyamide.

The present invention will be specifically described below with reference to Examples.

Example 1 The static melt mixer shown in FIG.
D = 1.5, D = 25 mm, n = 15, and a mixer in which the external heating of the pipe is an electric heater is attached to the screw out part of a 30 mmφ screw extruder (screw L/D-26), and the mixer is Nylon 6, nylon 66 and nylon 612 were reacted in the reactor.

That is, dried nylon 6 (relative viscosity 3.20 in 98% sulfuric acid solution at 25°C, hereinafter abbreviated as N-6), nylon 6
6 (relative viscosity: 2.52, hereinafter abbreviated as N-66) and nylon 612 (relative viscosity: 2.48, hereinafter abbreviated as N-612) chips each consisting of 35.50.15 parts by weight were mixed with a 30 mmφ screw. It was fed into the extruder.

The average temperature of a portion of the screw was set to 300° C., the screw rotation speed was set to 15 times/min, and the molten polymer was continuously supplied to the static melt mixer.

An electric heater was set so that the internal temperature of the mixer reached 320°C, and N-6, N-66, and N-612 were reacted in the mixer, and then the polymer was taken out in the form of a rope, cooled with water, and then chipped again. It was cut into pieces.

In this example, the reaction time in the static melt mixer was about 30 minutes.

The physical properties of the obtained polymer are shown in Table 1, and 3
It can be seen that there was almost no thermal damage despite the reaction at a high temperature of 20°C.

Comparative Example 1 35.50.15 g each of chips of nylon 6, nylon 66, and nylon 612 were charged into a 300 ml autoclave equipped with a stirrer.

After purging with dry nitrogen gas, the solvent was heated to 300°C to carry out a copolymerization reaction.

After reacting for a certain period of time, the polymer was taken out, and the melting point of the polymer was measured using a differential calorimeter (manufactured by Rigakusha, hereinafter abbreviated as DSC).

Approximately 6 hours of reaction was required to obtain a polymer having the same melting point as that obtained in Example 1 (202°C).

The physical properties of the obtained polymer are as shown in Table 1,
Thermal damage was extremely large compared to Example 1.

Further, as a result of examining the solubility of the obtained polymer 32 in 90% formic acid, insoluble matter was precipitated.

This is a gelled product formed during long-term heating.

Example 2 Random polyamide obtained by polycondensing 50.30.20% by weight of each of hexamethylene diammonium adipate, ε-caprolactam, and a salt of hexamethylene diamine and terephthalic acid (sulfuric acid relative viscosity 2.69, melting point 19)
7℃ (hereinafter abbreviated as N-C) chips and nylon
6. Chips of sulfuric acid (relative viscosity 3.20, melting point 225°C) were put into two screw extruders (screw L/D = 2).
6, D=25 mm), and quantitatively supplied to a static melt mixer at 10 g/min using a gear pump, and reacted at 300°C.

The static vessel mixer is of the type shown in Figure 2, that is, element 20 with L-23,5 mm and D=25 mm.
A pipe was filled with the sheets, and the outside of the pipe was heated with an electric heater.

The polymer after the reaction is 1m in diameter from the spinneret attached to the mixer outlet.
It was collected as a monofilament of m.

The obtained monofilament was free from coloration and foaming and had sufficient transparency and flexibility.

Further, the polymer physical properties of the monofilament are as shown in Table 2, and there was almost no thermal damage.

On the other hand, mixed chips consisting of 50,150 parts by weight of each of the above-mentioned NC chips and nylon-6 chips were supplied to only one of the above-mentioned screw type extruders.

The operating conditions of the extruder and static melt mixer were exactly the same as above, and only the amount of liquid fed by the gear pump was 20 g/min.

The polymer physical properties of the obtained monofilament are as shown in Table 2, and were almost similar to random copolymerized polyamide of the same composition obtained by polymerization from monomers.

It will be appreciated that in the practice of the present invention, the starting polyamides may be melted separately or simultaneously dynamically melt-mixed and then the copolymerization reaction may be carried out in a static melt mixer.

However, in order to obtain a sufficiently randomly copolymerized polyamide, it is more convenient to carry out the copolymerization reaction in a static melt mixer after dynamically melt-mixing the materials in advance.

Example 3 Dried nylon-6 (sulfuric acid relative viscosity 3.20), nylon-66 (sulfuric acid relative viscosity 2.52) and nylon-612
(same relative viscosity 2.48) chips each 48.14.38
The mixed chips consisting of parts by weight were reacted in the same manner as in Example 1.

However, the mixer used in this example is of the type shown in Figure 1, and the element L/D = 1.5, D-
40 mm, and the total number of elements is n-15.

In this example, the reaction temperature was 310° and the reaction time was 80 minutes.

The physical properties of the obtained polymer are as shown in Table 3, and were almost similar to the copolymerized polymer having the same composition ratio obtained by the monomer polymerization method.

It has been found that by carrying out the present invention, a random copolymer which is no different from the monomer polymerization method can be obtained from a polyamide which has already undergone a polycondensation reaction.

Further, as is clear from Example 1 and this example, in the present invention, a copolymer having an arbitrary composition ratio can be easily obtained using the same raw material polyamide.

[Brief explanation of the drawing]

FIGS. 1 and 2 show an example of a static melt mixer according to the present invention. In the figure, 1...pipe, 2. Total: Element, 4: Heating element.

Claims (1)

[Claims] When producing a copolyamide by reacting 12 or more types of polyamides, the reaction is carried out in a static melt mixer with a dividing layer width d defined by the following formula (where D is (Inner diameter of the pipe, A is the number of divisions of one element used, n is the total number of elements filled in the pipe, d is the width of the divided layer of polymer after passing through the n-th element) Until it becomes 10 μ or less A method for producing a copolyamide, which comprises melt-mixing. When producing a copolymerized polyamide by reacting 22 or more types of polyamides, the reaction is carried out in a static melt mixer after melt-mixing in advance using a screw or stirring blade, so that the divided layer width d defined by the following formula is ( Here, D is the inner diameter of the pipe, and A is the element 1 used.
The number of divided layers, n is the total number of elements filled in the pipe, and d is the width of the polymer divided layer after passing through the n-th element). Method for producing copolymerized polyamide.