JPH10265566A - Production of polyamide resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable to stably and simply obtain the subject resin excellent in heat resistance, having a high mol.wt. and effectively reduced in the gelation of the product by controlling a whole water content in the polyamide-producing reaction system to a specific value or lower. SOLUTION: This method for producing a polyamide resin comprises reacting (B) a linear polyester resin comprising (B1 ) a dicarboxylic acid component and (B2 ) a dihydric OH component and having an intrinsic viscosity of >=0.2 dl/g with (C) a diamine compound in (A) a reaction solvent comprising a (halogenated) hydrocarbon solvent, an ether solvent or a acetal solvent to replace the component B2 in the component B with the component C. Therein, the whole water content in the reaction system is controlled to <=1000 ppm based on the component B. For example, the total water content of the components A, B and C is controlled to <=1000 ppm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a polyamide resin, and more particularly to a method for obtaining a heat-resistant polyamide resin using a polyester resin as a raw material.

[0002]

2. Description of the Related Art Nylon 66, 46, 6T and aramid resins have recently been spotlighted as heat-resistant polyamide resins having excellent mechanical properties and chemical and physical properties, and have been used in various fields. And these nylon 66, 4
6, 6T and the like are generally produced by reacting an organic dicarboxylic acid and an organic diamine to form a nylon salt and subjecting it to dehydration polycondensation. However, this method has a problem that the process is complicated, and it is necessary to carry out polycondensation at a high temperature for a long time. Further, when producing an aramid resin, there is a problem that an expensive organic carboxylic acid dihalide is required as a raw material.

Accordingly, the present inventor has previously described in Japanese Patent Application No. Hei.
No. 2372 proposed a novel method for obtaining a polyamide resin via a polyester resin, which is completely different from the conventional polycondensation reaction method. That is, in such a production method, a polyester resin is used as a raw material instead of the conventional organic dicarboxylic acid component, and when the polyester resin is reacted with a diamine compound (polyamide formation), the molar ratio of the diamine compound is set to the polyester resin. Thus, the desired polyamide resin can be obtained in a very simple process and in a short time by setting the reaction temperature within a specific range and using a predetermined solvent as a reaction medium.

However, as a result of further studies by the present inventors, in order to make the polyamide resin obtained by such a production method a practically valuable high-molecular-weight one, it is necessary to use the above-mentioned polyamide conversion reaction. It is necessary to further raise the reaction temperature or to further lengthen the reaction time, or to further perform operations such as solid-phase polycondensation and melt polycondensation on the reaction product obtained by polyamideation. When such means are taken, the desired polyamide conversion reaction does not proceed effectively, and the product may gel, and the target polyamide It has been clarified that a problem that a resin cannot be stably obtained may occur.

[0005]

The inventor of the present invention has studied the above-mentioned method for producing a polyamide resin in more detail, and has found that such a problem is caused by hydrolysis of the raw material polyester resin. Gain knowledge and control the total amount of water present in the reaction system for the polyamidation to reduce such hydrolysis as much as possible, effectively suppressing the gelation of the product It has been found that the desired polyamide resin can be obtained relatively stably at a high molecular weight.

Accordingly, an object of the present invention is to provide a method for producing a polyamide resin via a polyester resin as described above, wherein a useful high molecular weight polyamide resin is easily obtained without gelling the product. It is to provide a practical method capable of doing this.

[0007]

The present invention provides a linear polyester resin comprising a dicarboxylic acid component and a divalent OH component and having an intrinsic viscosity of 0.2 dl / g or more. A diamine compound, a hydrocarbon solvent,
The reaction is carried out in a reaction medium comprising at least one solvent selected from the group consisting of halogenated hydrocarbon solvents, ether solvents and acetal solvents, and the divalent OH in the linear polyester resin is reacted. By substituting the components with the diamine compound, when producing a polyamide resin, the total water content in the reaction system is set to a ratio of 1000 ppm or less to the linear polyester resin, and the reaction is allowed to proceed. The feature is a method for producing a characteristic polyamide resin.

That is, in such a method for producing a polyamide resin, the total water content in the reaction system in which the polyamide conversion reaction proceeds, that is, each of the raw material linear polyester resin, the diamine compound, and the reaction medium When the total amount of water contained is set to 1000 ppm or less with respect to the linear polyester resin, hydrolysis of the polyester resin caused by the water present in such a reaction system becomes possible. As a result, the polyamide resin of the polyester resin can be effectively advanced without being hindered, thereby avoiding gelation of the product, and the desired polyamide resin Is advantageously obtained at a high molecular weight.

According to one preferred embodiment of the method of the present invention, the linear polyester resin has a water content of 1000 ppm or less, and the diamine compound has a water content of 1000 ppm or less. The water content of the reaction medium is 1000 ppm or less. As described above, the water content of each raw material component in the reaction system is regulated, so that the total water content in the reaction system can be easily reduced. Can be made to proceed more advantageously.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the method for producing a polyamide resin according to the present invention as described above, first, a linear polyester resin as a raw material used therein is, as well known, generally, It is obtained by a polycondensation reaction from a dicarboxylic acid component composed of an organic dicarboxylic acid or a derivative thereof and a divalent OH component composed of a dihydric alcohol compound or a dihydric phenol compound. Among them, as the organic dicarboxylic acid or a derivative compound thereof, for example, terephthalic acid, isophthalic acid, phthalic acid, dimethyl terephthalate, terephthalic acid dichloride, diphenyldicarboxylic acid, aromatic dicarboxylic acids such as naphthalenedicarboxylic acid and derivatives thereof and And aliphatic dicarboxylic acids such as oxalic acid, succinic acid, adipic acid, sebacic acid, maleic acid and fumaric acid, and derivatives thereof. Examples of the dihydric alcohol compound include ethylene glycol, propylene glycol, butane-1,3-diol, butane-1,
Examples thereof include alkylene glycols such as 4-diol and tetramethylene glycol, and cyclohexanediol. Further, examples of the dihydric phenol compound include bisphenol-A. The dicarboxylic acid component and the divalent OH component may each be constituted by one of the above examples alone or by a combination of two or more compounds.

Among such linear polyester resins, terephthalic acid is mainly used as a dicarboxylic acid component, and alkylene glycols such as ethylene glycol and butane-1,4-diol are mainly used as a divalent OH component. The polyalkylene terephthalate resin obtained by use is preferably used, and particularly preferably, a polyethylene terephthalate resin (hereinafter abbreviated as PET resin), and particularly, a recycled (recovered) PET resin is advantageously used.

In the present invention, two or more linear polyester resins may be used as a mixture, and other organic polymers and inorganic compounds may be mixed with the linear polyester resin. It may be. As the organic polymer that can be mixed with the linear polyester resin,
Polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, chlorinated polyethylene, polybutadiene, butyl rubber, polystyrene, styrene-acrylonitrile-butadiene copolymer, polyvinyl chloride, polyoxymethylene, polyamide, polyphenylene oxide , Polycarbonate and the like. Further, as the inorganic compound, talc, mica, calcium carbonate, titanium oxide, carbon black,
Alumina, glass beads, glass fiber, carbon fiber and the like can be mentioned.

The limiting viscosity of such a linear polyester resin is hexafluoroisopropanol (hereinafter referred to as HF).
(Abbreviated as IP) as a solvent, at a temperature of 30 ° C., at least 0.2 dl / g, preferably 0.3 dl / g.
g or more. However, at an intrinsic viscosity of less than 0.2 dl / g, the intrinsic viscosity of the polyamide resin obtained by the present invention is small, and even if a solid-phase polycondensation or melt polycondensation operation is further performed, the effect of improving the degree of polymerization is low, This is because an industrially useful high molecular weight polyamide resin cannot be obtained.

Further, the shape of the polyester resin used here is not particularly limited, but preferably the average particle size is generally 2 mm or less, more preferably 1 m or less.
m or less powdered forms are advantageously employed. The water content (moisture content) is generally 1000 ppm or less, preferably 500 ppm or less, more preferably 100 ppm or less, in order to facilitate making the total water content in the reaction system equal to or less than a predetermined value according to the present invention. It is desirable to be.

On the other hand, diamine compounds which can be reacted with such a linear polyester resin include:
Aliphatic diamines such as ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, octamethylenediamine, dodecamethylenediamine, trimethylene-1,6-hexamethylenediamine; p-phenylenediamine;
m-phenylenediamine, o-phenylenediamine,
2,3-tolylenediamine, 2,4-tolylenediamine, 2,5-tolylenediamine, 2,6-tolylenediamine, 3,4-tolylenediamine, 3,5-tolylenediamine, p- Xylylenediamine, m-xylylenediamine, o-xylylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminobiphenyl,
3,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dichloro-4,4'-diaminobiphenyl, 4,4'-diaminodiphenyl ether, 4,
4'-diaminodiphenylpropane, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfide, 4,4'-diaminobenzanilide,
3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 4,4'-diaminoanthraquinone, 3,
3'-dimethoxybenzidine, α, α'-bis (4-aminophenyl) -p-isopropylbenzene, 1,5-
Aromatic diamines such as diaminonaphthalene and 2,6-diaminonaphthalene; 1,3-diaminocyclohexane,
1,4-diaminocyclohexane, 1,3-bis (aminomethyl) cyclohexane, isophoronediamine, piperazine, 2,5-dimethylpiperazine, bis (4-aminocyclohexyl) methane, bis (4-aminocyclohexyl) propane, 4, 4'-diamino-3,3'-dimethyldicyclohexylmethane, α, α'-bis (4-
Aminocyclohexyl) -p-diisopropylbenzene, α, α'-bis (4-aminocyclohexyl) -m
-Alicyclic diamines such as diisopropylbenzene and menthanediamine; and amino-modified polymers such as diaminopolysiloxane. These diamine compounds may be used alone or in combination of two or more.

The moisture content (moisture content) of such a diamine compound is generally 1000 ppm or less, preferably 500 ppm or less, and more preferably 500 ppm or less, in order to facilitate the regulation of the total moisture content in the reaction system. Is desirably 100 ppm or less.

The amount of the diamine compound used here is desirably 0.5 to 1.5 mol with respect to 1 mol of the repeating unit of the linear polyester resin.
Especially, it is preferably 0.7 to 1.3 mol, more preferably 0.8 to 1.2 mol. When the amount of such a diamine compound is less than 0.5 mol, a good heat-resistant polyamide resin cannot be obtained, and when the amount of the diamine compound exceeds 1.5 mol, it is obtained. There are inherent problems that the molecular weight of the polyamide resin is small and that the polyamide resin is liable to become an insoluble and insoluble gelled product in a solid-phase polycondensation or melt polycondensation operation.

Further, according to the present invention, a specific solvent is used as a reaction medium in which a linear polyester resin is reacted with a diamine compound to cause a polyamide reaction to proceed, and specifically, n-butane is used. , I-butane,
n-pentane, 2-methylbutane, 2,2-dimethylpropane, 2-methylpentane, 3-methylpentane,
2,2-dimethylbutane, 2,3-dimethylbutane, n
-Hexane, n-heptane, 2-methylhexane, 3-
Methylhexane, 2,3-dimethylpentane, n-octane, n-nonane, n-decane, isodecane, tridecane, benzene, toluene, xylene, ethylbenzene,
Cumene, n-propylbenzene, n-butylbenzene,
aliphatic, aromatic, aliphatic-aromatic or alicyclic hydrocarbons such as n-octylbenzene, dodecylbenzene (linear, branched), cyclopentane, cyclohexane, decalin, tetralin, methylcyclopentane, methylcyclohexane, etc. Solvent: 1,2-dichloroethane, 1,1,
Halogenated hydrocarbon solvents such as 1-trichloroethane, chlorobenzene, p-chlorotoluene, o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, 3,4-dichlorotoluene, 1,2,3-trichlorobenzene; Diethyl ether, dipropyl ether, dibutyl ether, dihexyl ether, ethyl vinyl ether, butyl vinyl ether, anisole, phenetole, butyl phenyl ether, pentyl phenyl ether, methoxytoluene, benzylethyl ether, diphenylether, dibenzylether, trioxane, 2-methylfuran , Tetrahydrofuran, tetrahydropyran, 1,2-dimethoxyethane, 1,
Examples include ether-based and acetal-based solvents such as 2-diethoxyethane, 1,2-dibutoxyethane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, triethylene glycol diethyl ether, and diethyl acetal. When aromatic diamines and alicyclic diamines are used as the diamine compound among these solvents, hydrocarbon solvents and hydrophobic ether solvents are advantageously used.

These solvents may be used alone,
A mixture of two or more thereof may be used as a reaction medium. Therefore, as the reaction medium in the present invention, petroleum ether,
Petroleum benzene, gasoline, kerosene, or solvent naphtha would also be included. However, aldehydes, ketones, esters, carboxylic acids, alcohols, or phenolic solvents commonly used as a solvent, or water, etc., react with a diamine compound or hydrolyze a polyester resin. It is not suitable to use as a reaction medium in the present invention.

In order to easily regulate the total water content in the reaction system, the water content (moisture content) in such a solvent, and thus the reaction medium, is generally 1000 pp.
m or less, preferably 500 ppm or less, more preferably 100 ppm or less.

By the way, in the present invention, when the above-mentioned linear polyester resin is amidated, the total water content in the reaction system is reduced by one to the linear polyester resin.
By adjusting the concentration to 000 ppm or less, preferably 500 ppm or less, more preferably 100 ppm or less, hydrolysis of the polyester resin due to moisture present in such a reaction system is reduced as much as possible. As a result, the polyamide-forming reaction advantageously proceeded, so that the resulting polyamide resin could be effectively increased in molecular weight.

In the present invention, in order to control the total water content in the reaction system for polyamide conversion, for example, each raw material whose water content (moisture content) has been adjusted in advance according to a conventional method is prepared by subjecting each raw material to a predetermined content. By using the amount of each, it is possible to adopt a method such as controlling the total amount of water in the reaction system, it is also possible to combine some of the raw materials weighed by a predetermined amount in combination and blend, It is also possible to adopt a method of performing a water content adjustment operation on the composition and adjusting the total water content as a whole.

In the present invention, preferably,
The water content was 1000 ppm or less, respectively, a linear polyester resin, a diamine compound and a reaction medium,
Each will be used. Here, the method of adjusting the water content of each raw material is not limited at all, and various known methods are appropriately employed. For example, in a linear polyester resin, the moisture content can be easily reduced to 1000 ppm or less by performing treatments such as drying under reduced pressure and drying under heating, and the water content of the diamine compound and the reaction medium can be easily reduced. The adjustment can be easily performed, for example, by dissolving the diamine compound in the reaction medium, and using a suitable adsorbent such as molecular sieve, by dissolving the diamine compound in contact with the mixture and dehydrating the mixture. .

In order to produce a desired polyamide resin by amidating a predetermined straight-chain polyester resin, the straight-chain polyester resin and the diamine compound as reaction raw materials, and further, a predetermined reaction medium serving as a reaction medium are required. Solvent is charged in a suitable reaction vessel having a stirring function in each required amount, and heated under a condition such that the total water content in the reaction system is 1000 ppm or less of the linear polyester resin. This allows the desired reaction to proceed. In this case, the linear polyester resin as a raw material is allowed to react in a reaction vessel, generally, in a state of being dispersed in an undissolved slurry, in other words, in a heterogeneous system. Alternatively, it can be reacted with a diamine compound while being dissolved in a reaction medium under heating. However, the polyamide resin finally obtained by such a reaction is not dissolved in the reaction medium even under heating, and is generated in a slurry state. In addition, any of a batch method and a continuous method can be adopted for this reaction.

The reaction temperature employed in such a polyamide conversion reaction includes, in addition to the used polyester resin, diamine compound and solvent type and amount, reaction pressure, reaction time,
Although the temperature varies depending on the stirring state and the shape of the polyester resin, the temperature is generally 100 ° C. or higher and the melting point of the polyester resin to be used, preferably 120 ° C. or higher, and 10 ° C. or lower than the melting point of the polyester resin to be used. . At a reaction temperature of less than 100 ° C., it takes too much time to produce a polyamide resin, and the reaction temperature is
If the melting point of the polyester resin exceeds the melting point of the polyester resin to be used, the resulting polyamide resin will strongly adhere to the vessel wall of the reaction vessel, and insoluble and insoluble gel-like substances will be easily generated. When the reaction temperature is equal to or higher than the boiling point of the solvent (reaction medium) or diamine compound to be used, the reaction vessel is closed or pressurized.

Further, the reaction time for such a polyamide conversion depends on many factors as well as the reaction temperature, but is generally about 0.2 to 100 hours, preferably 0.5 to 50 hours. Time is desirable. However, if the reaction time is less than 0.2 hours, the production of the polyamide resin is not sufficient, and if the reaction time is more than 100 hours, the effect is reduced even if the time is extended longer.
This is because the generated polyamide resin causes problems such as insoluble and infusible gels.

After performing the polyamide reaction in this manner, the resultant is dispersed in a slurry in the reaction medium.
The polyamide resin as a reaction product is separated and recovered. As the separation and recovery method, a known method such as a usual filtration method, a centrifugal separation method, and a solvent spray drying method is used. The separated product thus obtained is completely dried by a usual dryer for performing hot air drying, vacuum drying, and the like, whereby the desired polyamide resin is obtained. The polyamide resin thus obtained has a limiting viscosity of generally 0.4 dl / g or more.

In order to further increase the molecular weight or the degree of polymerization of the polyamide resin as a reaction product obtained according to the method of the present invention, solid-phase polycondensation or melt polycondensation is performed on the reaction product. Implementation is an effective means and is advantageously employed in the present invention.

Specifically, the solid-phase polycondensation is a method in which a polycondensation reaction is advanced in a state where a solid state is maintained, thereby increasing the degree of polymerization. Between 50 ° C. above the glass transition temperature of the resin and the melting point, preferably 80 ° C. above the glass transition temperature
At a temperature 20 ° C lower than the melting point from 1000 ° C higher, 1000P
This is realized by performing a heat treatment under a reduced pressure of not more than a, preferably 300 Pa or less or under an inert gas. The heat treatment time at this time varies depending on the temperature, the amount of the reaction product, and the shape of the apparatus, but is generally about 0.2 to 20 hours, preferably about 0.5 to 10 hours.

In addition, melt polycondensation is a method in which a molten material is subjected to a shearing action while maintaining its molten state.
In this method, the polycondensation reaction is allowed to proceed under reduced pressure to increase the degree of polymerization. The temperature at which the shearing action is applied under such melting is generally higher than the melting point of the formed polyamide resin and lower than the decomposition temperature of the polyamide resin, preferably higher than the melting point of the formed polyamide resin by 20 ° C. or more. The temperature is 30 ° C. or less lower than the temperature. As a reaction device to which the melt shearing action can be applied, any device capable of kneading a high-viscosity polymer under heating conditions can be used. Specifically, rolls,
There are an extruder and a kneader. Among them, a vented extruder and a kneader, which can be easily kneaded at a high temperature, can have a high molecular weight in a short time, and can easily obtain a produced polymer, are preferable. Among them, a single-screw or multi-screw extruder is used as an extruder, and by using this, a reaction by-product can be distilled off under reduced pressure from a vent. The resin can be obtained in the form of pellets. The degree of pressure reduction of the vent is generally 1,000 Pa or less, preferably 300 Pa or less. The melt shearing time in the above melt polycondensation operation is usually 0.2 minutes or more and 15 minutes or less, preferably 0.5 minutes or more and 10 minutes or less.

The polyamide resin obtained according to the method of the present invention may contain, if necessary, various compounding agents such as known heat stabilizers, light stabilizers, coloring agents, lubricants, reinforcing agents, and fillers. Are compounded alone or in combination, and can be formed into a desired molded product by a usual melt molding method, for example, a method such as compression molding, injection molding, or extrusion molding. Further, by dissolving such a polyamide resin in a solvent, it can be used for forming a film by a casting method and forming a coating layer.

[0032]

Hereinafter, typical examples of the present invention will be described to clarify the present invention more specifically. However, the present invention imposes no restrictions on the description of such examples. It goes without saying that you don't receive anything. In addition, the present invention, in addition to the following examples, and in addition to the above-described specific description, various changes, modifications, and modifications based on the knowledge of those skilled in the art without departing from the spirit of the present invention. It should be understood that improvements can be made.

First, a commercially available PET resin bottle is collected, washed, pulverized, and sieved to obtain a 10-mesh wire mesh pass product (powder).
An ET resin powder was obtained. Then, the obtained PET resin powder which has not been subjected to the drying treatment is subjected to undried PET.
Resin powder (A) and dried PET resin powder (B) obtained by drying the recycled PET resin powder at a temperature of 130 ° C. for 1 hour are also referred to as dried PET resin powder (B).
Dried for 5 hours with dry PET resin powder (C)
And The water content of these PET resin powders was measured using a moisture meter manufactured by Mitsubishi Chemical Corporation.
(A) is 3100 ppm, (B) is 600 ppm,
(C) was 15 ppm. In this way, three types of PET resin powders (A), (B) having different moisture contents,
(C) was obtained.

Next, 1 part by weight of hexamethylenediamine (reagent first grade, manufactured by Wako Pure Chemical Industries, Ltd.), which is a diamine compound, is added to 10 parts by weight of o-dichlorobenzene (special grade of reagent, manufactured by Wako Pure Chemical Industries, Ltd.) as a solvent. The mixed and dissolved material was prepared as a mixed medium, and the mixed medium was subjected to a dehydration operation using Molecular Sieve 3A (manufactured by Wako Pure Chemical Industries, Ltd.). At this time, by changing the dehydration conditions, the mixed medium (C) having a water content of 300 ppm,
Two types of mixed media having different water contents were obtained from the mixed medium (D) having a water content of 15 ppm.

The above-mentioned PET resin powder (A)
To 110 g of (C), 733 g of the mixed medium (D) or (E) containing an equimolar amount of hexamethylenediamine in the repeating unit of PET was combined as shown in Table 1 below. Each was charged into a 1 L autoclave, the inside of the autoclave was replaced with nitrogen gas, and after sealing, the mixture was heated at a temperature of 180 ° C. for 10 hours with stirring to react. Thereafter, the temperature of the autoclave was lowered to room temperature, and the obtained reaction product was separated by filtration, washed with a larger amount of ethanol, and then separated by filtration again. Thereafter, vacuum drying was performed at a temperature of 120 ° C. for 24 hours to obtain a target polyamide resin. Then, for each of the obtained polyamide resins, the respective stoichiometric amounts, assuming that all the ester groups have been converted to amide groups, are as follows:
The yield was determined by dividing by g.

Embedded image

With respect to each powdery polyamide resin thus obtained, various physical properties were determined, and the results are shown in Table 1 below together with the yield.

The methods for evaluating various physical properties in Table 1 below are as follows. Amidation rate Indicates the rate at which the ester group was converted to an amide group. Each polyamide resin was mixed with KBr and formed into pellets, and the pellets were respectively measured with an FT-IR meter (1725X, manufactured by PERKIN ELMER, USA). Measured and 173 by ester group
Absorbance at 0 cm ^-1 (λ ₁₇₃₀ ) and 1540 due to amide group
The absorbance at cm ^-1 (λ ₁₅₄₀ ) was determined and calculated by the following equation. Amidation ratio (%) = λ ₁₅₄₀ / (λ ₁₇₃₀ + λ ₁₅₄₀ ) × 10
0

Melting point (Tm) Thermal analysis TGA meter (SSC / 520, manufactured by Seiko Co., Ltd. )
0, TG / DTA 220), and shows the melting point peak temperature obtained at a temperature rising rate of 10 ° C./min in a nitrogen atmosphere.

The limiting viscosity was measured using an Ubbelohde viscometer, using HFIP as a solvent, at a temperature of 30 ° C.

[0040]

As is clear from the results in Table 1 above, the polyamide resins of Experimental Examples 1 and 2 obtained in a reaction system having a total water content of 1,000 ppm or less with respect to the polyester resin had a total water content of 1000 ppm. As compared with the polyamide resins of Experimental Examples 3 and 4, which employed a reaction system exceeding
The amidation ratio and intrinsic viscosity became high.

[0042]

As is apparent from the above description, according to the method of the present invention, the total water content in the reaction system is reduced to 1000 ppm with respect to the linear polyester resin during the polyamide reaction of the linear polyester resin. By using the following ratios, it is possible to advantageously improve the amidation ratio and the molecular weight (intrinsic viscosity) of the target polyamide resin while preventing gelation of the product, thereby being more useful. A high molecular weight polyamide resin can be easily obtained.

Claims (4)

[Claims] 1. A linear polyester resin having a limiting viscosity of 0.2 dl / g or more, comprising a dicarboxylic acid component and a divalent OH component, and adding a diamine compound to a hydrocarbon solvent, a halogenated hydrocarbon, In a reaction medium comprising at least one solvent selected from the group consisting of a system solvent, an ether solvent and an acetal solvent, and reacting the divalent OH component in the linear polyester resin with the diamine. By producing a polyamide resin by substituting with a compound, the total water content in the reaction system is set to a ratio of 1000 ppm or less with respect to the linear polyester resin, and the reaction is allowed to proceed. Method of manufacturing resin. 2. The method for producing a polyamide resin according to claim 1, wherein the water content of the linear polyester resin is 1,000 ppm or less. 3. The water content of the diamine compound is 10
The method for producing a polyamide resin according to claim 1 or 2, wherein the amount is not more than 00 ppm. 4. The reaction medium has a water content of 1000 p
4. The method for producing a polyamide resin according to claim 1, wherein the pressure is pm or less. 5.