JPH0827378A - Production of polyamide molding - Google Patents

Abstract

PURPOSE:To obtain a high molecular weight polyamide molding which can be adapted to a film and extrusion by a method wherein a specified polyamide resin mixture is mixed with specified compound(s) and this mixture is molded while reacted in a melt kneader. CONSTITUTION:A polyamide resin mixture comprising 60-90wt.% nylon 46 resin and 40-10wt.% nylon 6 and/or nylon 66 resin which satisfies the formula, [NH2-[COOH]>20 (wherein [NH2] and [COOH] respectively are a terminal amino group content and a terminal carboxyl group content in gram equivalents/10<6>g) is mixed with a compound of formula I[wherein X is (substituted) ethylene or (substituted) trimethylene, forming a 5- or 6-membered crylic structure, with the substituents being a 1-10C alkyl, a 6-15C aryl, a 5-12C cycloalkyl, etc.; D is a 1-10C alkylene, a 6-15C arylene, etc.; and (n) is 0 or 1] and/or a compound of formula II (wherein Y is an alkylene or an aromatic group; and R is an alkyl), and this mixture is molded while reacted in a melt kneader.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for producing a polyamide molded body, and more particularly to a method for producing a nylon 46 molded body having a high molecular weight during melt molding and uses of the film produced by the method of the present invention.

[0002]

Nylon 46 made from tetramethylenediamine or its functional derivative and adipic acid or its functional derivative is excellent in mechanical strength such as tensile strength, bending strength, impact strength, heat resistance and sliding characteristics. Because it is also excellent, it has great utility value as a useful engineering plastic.

Conventionally, this resin is mainly produced by injection molding,
General-purpose polyamide centered on nylon 66 has heat resistance,
It has been applied to applications where sliding properties and chemical resistance are somewhat insufficient. Moreover, the demand for films and extrusion-molded products has been increasing recently, and the actual situation is that nylon 66 is mainly applied to the field where heat resistance is insufficient. Especially, the demand for high heat-resistant film is strong especially in the food field. .

It is desirable to increase the melt viscosity and slow the crystallization speed in order to adapt to the inflation method suitable for forming into these films, especially the bag-like shape. However, ordinary nylon 46 does not satisfy these characteristics, and it is difficult to form a film. In order to deal with this, it is necessary to increase the viscosity at the time of melting, and there is a strong demand for a method for producing a molded product using high molecular weight nylon 46.

In the meantime, in order to obtain a high-molecular-weight molded product, the conventional method is to melt-mold chips having a high-molecular weight in advance in a kneader such as an extruder. In the case of nylon 46, its resin is used. It is difficult to increase the molecular weight by an economical method due to the property.

That is, since the melting point is as high as 290 ° C. and it is close to the decomposition point of the resin, the degree of polymerization which can be used as a molded article cannot be reached by the usual melt polymerization method, and therefore, JP-A-56-149430 and JP-A-56-149430. The special solid-state polymerization method described in JP-A-56-149431 had to be used. Therefore, in order to further improve the degree of polymerization, it is necessary to adopt more severe solid-state polymerization conditions. This not only has low productivity, but it is difficult to control the degree of polymerization. On the other hand, as another method for obtaining a polyamide having a high degree of polymerization, British Patent No. 693645
In the specification, there is disclosed a method of adding a bis-N-acyl lactam type chain linking agent during the polymerization of polyamide.
Japanese Patent Laid-Open No. 1-171732 proposes a method in which a carbamoyllactam type chain linking agent is added to a polyamide and the reaction is carried out in an extruder. However, in the case of nylon 46, the former method by melt polymerization cannot be adopted, and the latter method is not satisfactory because the effect of increasing the degree of polymerization of the polymer obtained is small.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its object is to obtain a high molecular weight nylon 46, regardless of the solid-state polymerization method which has low productivity and is difficult to control the degree of polymerization. It is an object of the present invention to provide a method capable of being made compatible with film and extrusion molding.

The present inventors have already proposed in JP-A-3-62826 a method for obtaining a high molecular weight nylon 46 molded article. In this method, amino terminal groups of 46 molecules of nylon are linked with a biscaprolactam compound to increase the molecular weight. However, after the examination,
It has been found that the number of amino terminal groups of nylon 46 is not always stable, and when the number of amino terminal groups is small, a sufficient effect of increasing the molecular weight is not exhibited. The present invention has found a method for efficiently obtaining a high-molecular-weight nylon 46 molded product even under such circumstances.

[0009]

The present inventors have arrived at the present invention as a result of extensive studies aimed at achieving the above object.

The present invention relates to (A1) nylon 46 resin 60
~ 90 wt% and (A2) Nylon 6 that satisfies the following formula
And / or nylon 66 resin 40 to 10 wt%, [NH ₂ ]-[COOH]> 20 (where [NH ₂ ] and [COOH] are each gram equivalent /
It represents the amount of terminal amino groups and the amount of terminal carboxyl groups in 10 ⁶ gram units. ) Polyamide resin mixture 10
With respect to 0 parts by weight, (B) the following general formula (I)

[0011]

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[Wherein X is a divalent organic group selected from the group consisting of ethylene, substituted ethylene, trimethylene and substituted trimethylene, and the ring structure is a 5-membered ring or a 6-membered ring. The substituent of the substituted ethylene or substituted trimethylene is an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 15 carbon atoms, a cycloalkyl group having 5 to 12 carbon atoms, and 8 to 8 carbon atoms.
20 aralkyl groups. D in the formula has 1 to 1 carbon atoms
It is a divalent organic group selected from the group consisting of an alkylene group having 0, an arylene group having 6 to 15 carbon atoms, a cycloalkylene group having 5 to 12 carbon atoms, and an aralkylene group having 8 to 20 carbon atoms. Further, n in the formula is 0 or 1. ] And / or (C) the following general formula (II)

[0013]

[Chemical 4]

[In the formula, Y is a divalent alkylene group or an aromatic group, and R is an alkyl group. ] The compound shown by these is added, and it shape | molds, making it react in a melt-kneading machine, It is a manufacturing method of the polyamide molded body characterized by the above-mentioned. The present invention will be described in detail below.

The component (A1) nylon 46 resin used in the present invention is a polyamide obtained by a condensation reaction using adipic acid or its functional derivative as the acid component and tetramethylenediamine or its functional derivative as the amine component. However, a part of the adipic acid component or the tetramethylenediamine component may be replaced with another copolymerization component.

Preferred embodiments of nylon 46 resin are JP-A-56-149430 and JP-A-56-1494.
No. 31 is described.

The nylon 6 resin as the component (A2) used in the present invention means a linear polymer obtained by polymerizing ε-caprolactam, but within a range that does not impair the basic properties of nylon 6, ε- Monomers other than caprolactam may be copolymerized or blended. Here, in order to prepare Nylon 6 having more amino terminal groups than carboxyl terminal groups, it is necessary to add a small amount of an amine component to ε-caprolactam for polymerization. In this case, the amine component may be a monoamine, but it is more advantageous to use a diamine from the viewpoint of polymerization rate. Examples of the diamine include hexamethylenediamine, aliphatic amines such as m-xylylenediamine, and aromatic amines such as p-phenylenediamine and m-phenylenediamine, but any heat-stable one may be used. .

The component (A2) nylon 66 resin used in the present invention is a polyamide containing polyhexamethylene adipamide and hexamethylene adipamide units as main constituents. This resin is prepared by a conventional melt polymerization method, that is, a substantially equimolar salt of hexamethylenediamine and adipic acid, which are raw materials, is charged into a polymerization tank together with water, and the amount is adjusted to 250 to 300.
It can be obtained by a method in which polymerization is carried out at a temperature of about 0 ° C. under normal pressure, increased pressure or reduced pressure. At this time, a nylon 66 resin having more amino terminal groups than carboxyl terminal groups can be obtained by adding a small amount of amine component and polymerizing the same as in nylon 6.

Here, the important requirement required for the component (A2) is the amount of the terminal group, and [NH ₂ ]-[COOH]> 20 (where [NH ₂ ] and [COOH] are grams respectively. Equivalent /
It is necessary to satisfy the condition (representing the amount of terminal amino groups and the amount of terminal carboxyl groups in 10 ⁶ gram units). If this condition is not satisfied, the final polymerization degree will not be high, and thus high viscosity during molding cannot be obtained. Particularly preferred range is _{[NH 2] - [COOH]} > 40.

The proportion of the components (A1) and (A2) in the present invention is 60 to 90:40 to 10 by weight.
The component (A2) is an essential component for obtaining a high viscosity at the time of molding and an appropriate decrease in the crystallization rate, and the ratio thereof is 10
If it is less than wt%, this improvement effect is small, while 4
When it exceeds 0 wt%, the heat resistance represented by HDT (load deflection temperature) and the like is lowered, and the characteristics of nylon 46 are impaired, which is not preferable.

The compound (B) used in the present invention is represented by the following general formula (I).

[0022]

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In the formula, X is a divalent organic group, and the ring structure is a 5-membered ring or a 6-membered ring. Examples of X include ethylene, substituted ethylene, trimethylene, and substituted trimethylene. The substituted ethylene or substituted trimethylene has a substituent having 1 to 10 carbon atoms, an aryl group having 6 to 15 carbon atoms, and 5 to 12 carbon atoms. And cycloalkyl groups and aralkyl groups having 8 to 20 carbon atoms. More specifically, examples of the alkyl group include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, ethylhexyl, nonyl and decyl, and examples of the aryl group include phenyl, naphthyl, diphenyl and the following general formula ( An aryl group represented by III),

[0024]

[Chemical 6]

(Here, R'is --O--, --CO--, --S--, --SO
₂-,-CH₂-,-CH₂CH₂― 、 ― C (CH₃) ₂-Etc. )
And the like, and cycloalkyl is cyclohexyl.
Sill can be illustrated. Of these, X is ethylene,
Trimethylene is particularly preferred. In the formula, D is a divalent organic group
Is, for example, an alkylene group having 1 to 10 carbon atoms, a carbon number
6 to 15 arylene group, 5 to 12 carbon cycloalkyl
Len group, aralkylene group having 8 to 20 carbon atoms, and the like.
It More specifically, the alkylene group is methylene,
Ethylene, propylene, butylene, pentamethylene,
Xamethylene, heptamethylene, octamethylene, nona
Examples are methylene, decamethylene, dimethylmethylene, etc.
Phenylene and naphthylene as the arylene group.
And diphenylene, and an amide represented by the following general formula (IV)
Rylene group,

[0026]

[Chemical 7]

(Here, R'is --O--, --CO--, --S--, --SO
₂-,-CH₂-,-CH₂CH₂― 、 ― C (CH₃) ₂-Etc. )
And the like, and examples of cycloalkylene include cyclohexyl.
Xylene can be illustrated. In addition, n in the formula is 0 or 1.
It

The compound represented by the general formula (I) has a 5-membered ring as a compound called bisoxazoline and a 6-membered ring as a bisoxazine. Specifically, the following compounds can be exemplified.

2,2'-bis (2-oxazoline), 2,2'-bis (4-methyl-2-oxazoline), 2,2'-bis (4,4-dimethyl-2-oxazoline), 2 2,2'-bis (4-ethyl-2-oxazoline) 2,2'-bis (4,4-diethyl-2-oxazoline), 2,2'-bis (4-propyl-2-oxazoline), 2, 2 '
-Bis (4-butyl-2-oxazoline), 2,2'-bis (4-hexyl-2-oxazoline), 2,2'-bis (4-phenyl-2-
Oxazoline), 2,2'-bis (4-cyclohexyl-2-oxazoline), 2,2'-bis (4-benzyl-2-oxazoline), 2,2'-p-phenylenebis (2-oxazoline), 2,
2'-m-phenylene bis (2-oxazoline) 2,2'-o-phenylene bis (2-oxazoline), 2,2'-p-phenylene bis (4-methyl-2-oxazoline), 2,2 ' -p-phenylene bis (4,4-dimethyl-2-oxazoline), 22'-m-phenylene bis (4-methyl-2-oxazoline), 2,2'-m-phenylene bis (4,4-dimethyl) -2-oxazoline), 2,2'-ethylenebis (2-oxazoline), 2,2'-tetramethylenebis (2-oxazoline), 2,2'-hexamethylenebis (2
-Oxazoline), 2,2'-octamethylenebis (2-oxazoline), 2,2'-decamethylenebis (2-oxazoline), 2,2'-ethylenebis (4-methyl-2-oxazoline), 2 Bisoxazolines such as 2,2'-tetramethylenebis (4,4-dimethyl-2-oxazoline), 2,2'-cyclohexylenebis (2-oxazoline) and 2,2'-diphenylenebis (2-oxazoline) Compounds; and 2,2'-bis (5,6-dihydro-4H-1,3-oxazine), 2,2'-methylenebis (5,6
-Dihydro-4H-1,3-oxazine), 2,2'-ethylenebis (5,6-dihydro-4H-1,3-oxazine), 2,2'-propylenebis (5,6-dihydro-4H -1,3-oxazine), 2,2'-butylene bis (5,6-dihydro-4H-1,3-oxazine), 2,2 '
-Hexamethylenebis (5,6-dihydro-4H-1,3-oxazine), 2,2'-p-phenylenebis (5,6-dihydro-4H-1,3-
Oxazine), 2,2'-m-phenylene bis (5,6-dihydro-
4H-1,3-oxazine), 2,2'-naphthylenebis (5,6-dihydro-4H-1,3-oxazine), 2,2'-p, p'-diphenylenebis (5,6-dihydro -4H-1,3-oxazine) and other bisoxazine compounds.

Of these compounds, 2,2'-bis (2
-Oxazoline), 2,2'-p-phenylenebis (2-oxazoline), 2,2'-m-phenylenebis (2-oxazoline),
2,2'-bis (5,6-dihydro-4H-1,3-oxazine), 2,2'-
p-Phenylenebis (5,6-dihydro-4H-1,3-oxazine), 2,2'-m-phenylenebis (5,6-dihydro-4H-1,3-
Oxazine is preferred.

These compounds (B) can be easily prepared by a method in which a corresponding bisamide alcohol is treated with a dehydrating agent such as concentrated sulfuric acid or thionyl chloride to close the ring, or a method in which the corresponding bisamide halide is treated with an alkali to close the ring. Although it can be synthesized, it is not limited to these methods, and other methods can be appropriately used.

The compound (C) used in the present invention is represented by the following general formula (II).

[0033]

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In the formula, Y is a divalent alkylene group or aromatic group, and R is an alkyl group. Specific examples of the compound represented by the general formula include N, N′-isophthaloylbis-ε-caprolactam, N, N′-adipoylbis-ε-caprolactam, N, N′-adipoylbis-ε. -Valerolactam, N, N'-isophthaloylbisvalerolactam, N, N'-isophthaloylbisbutyrolactam and the like can be mentioned.

These compounds can be easily synthesized by reacting the corresponding carboxylic acid dihalide and lactam in the presence of an amine or an inorganic alkali such as KOH.

In the present invention, the polyamide resin mixture comprising (A1) and (A2) is reacted with the compound (B) represented by the general formula (I) and / or the compound (C) represented by the general formula (II). In general, the composition is dry-blended in advance and melt-kneaded.

Compound (B) for nylon 46
Is 0.3 part by weight or more based on 100 parts by weight of the polyamide resin mixture. If the addition amount is too small, the thickening effect is insufficient, and the particularly preferable addition amount is 0.75 to 2.
It is 0%. The thickening effect saturates even if more than a certain amount is added.
It becomes economically negative.

On the other hand, the amount of the compound (C) added is such that the amount of the acyl group of the component (C) is 0.5 to 3.0 times equivalent, based on the amount of the amino terminal group of the polyamide resin mixture.
〜2.0 times equivalent is desirable. If the amount added is too large, a decrease in molecular weight is observed, which is not preferable.

The melting temperature at this time is 5 to 30 ° C., preferably 5 to 15 ° C. higher than the melting point of nylon 46, and the kneading time is 1 to 15 minutes, preferably 2 to 6 minutes.

According to the present invention, it is possible to increase the degree of polymerization of nylon 46, which results in an increase in viscosity during melting and a decrease in crystallization temperature. As a result, it becomes possible to manufacture a molded body by film molding or extrusion molding, which has been difficult in the past, and it becomes possible to utilize nylon 46 resin beyond the frame of injection molding.

The method in which the effect of the present invention is most significantly exhibited is the production of a film by the inflation method. The film can be formed by a general blown film processing apparatus, and it can be used in either the upward direction or the downward direction. The temperature of the screw cylinder and die at this time is 280 to 320 ° C., and the kneading time is preferably 3 to 6 minutes.

The inflation film produced by the above-mentioned method can be used as a food heating bag because of its characteristics. Recently, 2 foods have been cooked by an instant heating cooker.
A method of heating for a short time (30 to 60 seconds) at a high temperature of around 00 ° C. has attracted attention, but at this time, it is necessary to wrap the food with a film, and a film that can withstand the high temperature has been demanded. It has been found that the blown film of the present invention is extremely suitable for this application because it is easy to form a bag as a feature of heat resistance and inflation. The thickness of the film is 50 μm or less, and preferably 15 to 40 μm. A bag using an inflation film developed from such a background is expected to be greatly expanded in the future as a heating bag for various articles and a bag for heat sterilization, in addition to being suitably used as the above-mentioned food heating bag. It is a thing.

[0043]

EXAMPLES Examples will be described below, but the present description is not limited thereto. The various methods used in the examples and comparative examples were measured by the following methods. (1) Terminal group amount The amino terminal group amount [NH ₂ ] was determined by dissolving the polymer in m-cresol and titrating with 0.01 N p-toluenesulfonic acid. The amount of terminal carboxyl groups [COOH] was determined by dissolving the polymer in benzyl alcohol and titrating with 0.1 N sodium hydroxide. (2) Deflection temperature under load (HDT) According to ASTM D648, the load was measured at a load of 264 Psi and a test piece thickness of 1/4 inch. (3) Crystallization temperature Differential Scanning Calor made by Du Pont Instruments
Temperature rise / fall rate 20 ℃ / min, 330 ℃
Was measured at a holding time of 3 minutes. (4) Melt viscosity RHEOGRAPH2002 manufactured by GOETTFERT
Measurement temperature 300 ℃, holding time 4 minutes, shea
It was measured at r rate 1000 (1 / sec).

The following materials were used in Examples and Comparative Examples.

Component (A1) As nylon 46, STANYLKS400 manufactured by DSM Co. of the Netherlands was used.

Component (A2) The following (a) to (e) were used as nylon 6 and nylon 66. (A) By adding 0.26 mol% of diethylenetriamine to ε-caprolactam, melt polymerization, washing with hot water, and drying, [η] = 1.08, [NH ₂ ] = 97,
A chip having [COOH] = 28, water content = 0.05%, and monomer content = 0.2% was obtained. (B) [η] = 1.41, [NH ₂ ] = 66, [C] by adding 0.25 mol% of m-xylylenediamine to ε-caprolactam, melt-polymerizing, washing with hot water and drying.
OOH] = 18, water content = 0.05%, monomer content =
0.2% chips were obtained. (C) [η] = 1.34, [NH ₂ ] = 4 by melt-polymerizing ε-caprolactam, washing with hot water, and drying.
5, chips having [COOH] = 46, water content = 0.05%, monomer content = 0.2% were obtained. (D) 0.39 mol% of terephthalic acid was added to ε-caprolactam, melt polymerization was performed, and hot water washing and drying were performed to obtain [η] = 1.21, [NH ₂ ] = 5, [COOH] =
86, water content = 0.05%, monomer content = 0.2%
Got the chips. (E) Hexamethylenediamine (0.25 mol%) is added to the AH salt, and melt polymerization is performed [η] = 1.37, [NH ₂ ] =
68, [COOH] = 20 chips were obtained. The polyamide resin mixtures of Examples and Comparative Examples were manufactured by using a twin-screw extruder (TEX4).
4, made by Nippon Steel Co., Ltd., cylinder temperature 270-330 ℃
Was extruded into pellets. A predetermined amount of bisoxazoline powder and / or terephthaloylbiscaprolactam powder was dry-blended with the obtained pellets and subjected to a test.

Compositions and test evaluation results are shown in Tables 1 and 2 as Examples and Comparative Examples.

The film forming properties in the table were determined by the following method. A film having a thickness of 25 μm was formed at a cylinder temperature of 290 to 310 ° C. and a die head temperature of 310 to 320 ° C. with an inflation film processing device (downward method), and the film was evaluated based on the retrievability, thickness unevenness, surface property and the like at the time of molding.

[Examples 1 to 10 and Comparative Examples 1 to 5] In Examples 1 and 2, the melt viscosity was increased and good film-forming properties were obtained. On the other hand, in the example of Comparative Example 1 in which the thickener is not added, the viscosity is low and the film forming property is poor. On the other hand, in a system not using Nylon 6 (Comparative Example 2), the crystallization temperature is high and it solidifies rapidly, so that sufficient film forming properties cannot be obtained. On the other hand, in Comparative Example 3, since the amount of nylon 6 is too much, the HDT becomes low and the characteristics of nylon 46 are lost. In Examples 3 and 4, (A
2) Similar effects can be obtained by changing the types of components.

In Comparative Examples 4 and 5, as the component (A2), [NH
₂ ]-[COOH]> 20 This is an example using Nylon 6 which does not satisfy the condition, and the melt viscosity is low and the film forming property is poor.

Examples 5 and 6 are examples in which the amount of bisoxazoline was changed, and Examples 7 and 8 were those in which the type of bisoxazoline was changed.

Examples 9 and 10 are examples in which biscaprolactam was used as a thickener, and the melt viscosity was increased and good film-forming properties were obtained.

[0053]

[Table 1]

[0054]

[Table 2]

Example 11 Using the polyamide resin composition having the composition of Example 2, a blown film processing apparatus (downward method) was used to form a film having a cylinder temperature of 290 to 320 ° C., a die temperature of 310 ° C., a width of 190 mm and a thickness of 25 μm. Was formed into a film. This film was cut and one end was sealed to make a bag. When bread was put in this bag and heated in an instantaneous heating cooker at about 200 ° C. for 45 seconds, there was no film damage such as melting and the bread could be heated in the same state as freshly baked.

[0056]

The polyamide resin composition of (A1) nylon 46 and (A2) nylon 6 and / or nylon 66 satisfying specific conditions is reacted with a bifunctional oxazoline or oxazine and / or biscaprolactam as a chain linking agent. By increasing the molecular weight by means of film formation and extrusion molding, it becomes possible to obtain a nylon 46 resin molded product that maintains the heat resistance of nylon 46.

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Claims (7)

[Claims] 1. (A1) Nylon 46 resin 60 to 90w
t% and (A2) Nylon 6 and / or nylon 66 resin satisfying the following formula: 40 to 10 wt% [NH ₂ ]-[COOH]> 20 (where [NH ₂ ] and [COOH] are each gram equivalent /
Polyamide resin mixture 100 consisting of 10 ⁶ gram units representing the amount of terminal amino groups and the amount of terminal carboxyl groups)
With respect to parts by weight, (B) the following general formula (I): [In the formula, X is a divalent organic group selected from the group consisting of ethylene, substituted ethylene, trimethylene, and substituted trimethylene, and the ring structure is a 5-membered ring or a 6-membered ring. The substituent of the substituted ethylene or the substituted trimethylene has 1 to 1 carbon atoms.
They are an alkyl group having 10 carbon atoms, an aryl group having 6 to 15 carbon atoms, a cycloalkyl group having 5 to 12 carbon atoms, and an aralkyl group having 8 to 20 carbon atoms. D in the formula is an alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 15 carbon atoms, and 5 to 1 carbon atoms.
It is a divalent organic group selected from the group consisting of a cycloalkylene group having 2 and an aralkylene group having 8 to 20 carbon atoms. Further, n in the formula is 0 or 1. ] And / or (C) the following general formula (II): [Wherein Y is a divalent alkylene group or an aromatic group,
R is an alkyl group. ], A compound represented by
A method for producing a polyamide molding, which comprises molding while reacting in a melt-kneader. 2. The method for producing a polyamide molded article according to claim 1, wherein the amount of the compound represented by the general formula (I) added is 0.3 part by weight or more based on 100 parts by weight of the polyamide resin mixture. 3. The compound represented by the general formula (I) is 2,
2'-m-phenylene bis (2-oxazoline), 2,
2'-p-phenylene bis (2-oxazoline), 2,
The method for producing a polyamide molded body according to claim 1, which is at least one compound selected from the group of 2'-bis (2-oxazoline). 4. The amount of the compound represented by the general formula (II) added is such that the amount of the acyl group of the compound represented by the general formula (II) is 0.5 to the amount of the amino terminal group of the polyamide resin mixture.
The method for producing a polyamide molded product according to claim 1, wherein the amount is in the range of 3.0 times equivalent. 5. A compound represented by the general formula (II) is N,
The method for producing a polyamide molded body according to claim 1, which is N'-terephthaloylbis-ε-caprolactam. 6. The method for producing a polyamide molded article according to claim 1, wherein the polyamide molded article is a film produced by an inflation method. 7. A food heating bag using the film produced by the method according to claim 6.