JP2003192890A - Polyamide resin composition and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyamide resin composition having the surface appearance and toughness comparable to those of non-reinforced polyamide and exhibiting excellent dimensional stability, strength and rigidity and provide a method for producing the composition. <P>SOLUTION: The polyamide resin composition containing a plate-form aluminum compound dispersed in a polyamide resin is produced by heating (A) a polyamide-forming monomer, (B) water and (C) an aluminum source under pressure to proceed the polymerization reaction of the polyamide and the hydrothermal synthetic reaction of the plate-form aluminum compound in the same reactor. The plate-form aluminum compound is present in an arbitrary cross-section of the polyamide resin composition dispersed at an average length of 20-300 nm and an average thickness of 1-10 nm. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyamide resin composition and a method for producing the same. More specifically, it relates to a polyamide resin composition having the same surface appearance and toughness as non-reinforced polyamide, and excellent in dimensional stability, strength and rigidity, and a method for producing the same.

[0002]

2. Description of the Related Art Techniques for blending fibrous reinforcements such as glass fibers and mineral reinforcements such as calcium carbonate and talc are widely used to improve heat resistance and dimensional stability of polyamides such as nylon 6 and nylon 66. Are known. However, in the polyamide resin containing these reinforcing materials, since the reinforcing material dispersed in the polyamide resin is raised on the surface of the molded product and the light rays are diffusely reflected, it is usually possible to avoid the deterioration of the surface appearance of the molded product. Absent. Further, since the reinforcing material is an inorganic substance, it is unavoidable that the toughness such as tensile elongation is lowered.

Attempts have also been made to use alumina or boehmite having a needle-like or plate-like form as a reinforcing material. For example, Japanese Patent Laid-Open No. 2001-261976 discloses at least one of plate-like boehmite and plate-like alumina. A resin composition containing as a filler is disclosed. Using these techniques, does not affect the surface appearance of the molded product, and
In order to minimize the deterioration of toughness and strengthen the resin,
It is generally known that it is sufficient to reduce the size of the filler used, but the smaller the size of the filler such as boehmite or alumina added to the resin, the more difficult it becomes to uniformly disperse it in the resin. There was a problem. Further, in the case of a fine filler having an outer diameter size of less than 0.5 μm, the bulk specific gravity of the filler itself becomes small, which makes it difficult to supply or mix the filler with ordinary compound equipment, which is a problem in terms of handling. Was also occurring. Therefore, it has been difficult to manufacture a polyamide resin reinforced with boehmite or alumina having an outer diameter size of less than 0.5 μm.

[0004]

Therefore, the present invention provides a reinforced polyamide resin which exhibits a high reinforcing effect with a small amount of an inorganic filler added, has a low specific gravity and an excellent surface appearance, and has excellent dimensional stability, strength and rigidity. It is intended to provide a composition.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a polyamide resin can be obtained by polymerizing a polyamide-forming monomer, water, and an aluminum source under pressure. The present inventors have found that it is possible to obtain a composition in which plate-like crystals of an aluminum compound having a minute size are dispersed, and by which the above problems can be solved, and the present invention has been accomplished.

That is, the present invention provides (1) a polyamide resin composition comprising a polyamide resin and a plate-like aluminum compound dispersed therein, wherein the plate-like aluminum compound is contained in the polyamide resin composition. Average particle size 2
A polyamide resin composition, which is present in a dispersed state of 0 to 300 nm and an average thickness of 1 to 10 nm,
(2) The polyamide resin composition according to (1) above, wherein the aluminum compound is boehmite.
(3) (A) polyamide-forming monomer, (B) water,
(C) The polyamide according to the above (1) or (2), which is obtained by heating an aluminum source under a pressurized condition and advancing a polymerization reaction of a polyamide and a hydrothermal synthesis reaction of a plate-shaped aluminum compound in the same reaction vessel. Resin composition, (4) Polyamide resin composition according to the above (3), wherein the aluminum source (C) is aluminum hydroxide, (5)
(A) A polyamide-forming monomer, (B) water, and (C) an aluminum source are heated under pressure to allow a polymerization reaction of polyamide and a hydrothermal synthesis reaction of a plate-shaped aluminum compound to proceed in the same reaction vessel. A method for producing the polyamide resin composition according to (1) or (2) above,
(6) A method for producing a polyamide resin composition according to (5) above, wherein the composition of the polyamide-forming monomer is in excess of amine.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The polyamide resin used in the present invention is a polyamide whose main raw materials are amino acids, lactams or diamines and dicarboxylic acids. Typical examples of the raw material include amino acids such as 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and para-aminomethylbenzoic acid, ε-caprolactam,
Lactams such as ω-laurolactam, tetramethylenediamine, hexamerenediamine, 2-methylpentamethylenediamine, undecamethylenediamine, dodecamethylenediamine, (2,2,4- or 2,4,4-) trimethylhexamethylene Diamine, 5-methylnonamethylenediamine, metaxylylenediamine, paraxylylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane,
1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis (4-aminocyclohexyl)
Of aliphatic, alicyclic or aromatic compounds such as methane, bis (3-methyl-4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, bis (aminopropyl) piperazine, aminoethylpiperazine Diamine, and adipic acid, speric acid, azelaic acid, sebacic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2-methylterephthalic acid, 5-methylisophthalic acid, 5-sodiumsulfoisophthalic acid, Examples thereof include aliphatic, alicyclic and aromatic dicarboxylic acids such as hexahydroterephthalic acid and hexahydroisophthalic acid. In the present invention, the polyamide homopolymers or copolymers derived from these raw materials can be used alone or in the form of a mixture.

In the present invention, the polyamide resin used particularly preferably is a polyamide resin having a melting point of 200 ° C. or higher. By using such a polyamide, it is possible to obtain a molded product having excellent heat resistance and strength. Specific examples include polycaproamide (nylon 6), polyhexamethylene adipamide (nylon 66), polycaproamide / polyhexamethylene adipamide copolymer (nylon 6/66), polytetramethylene adipamide ( Nylon 46), polyhexamethylene sebacamide (nylon 610), polyhexamethylene dodecamide (nylon 612), polyhexamethylene terephthalamide / polycaproamide copolymer (nylon 6T / 6), polyhexamethylene terephthalamide / polydodecane Amide copolymer (nylon 6
T / 12), polyhexamethylene adipamide / polyhexamethylene terephthalamide copolymer (nylon 66
/ 6T), polyhexamethylene adipamide / polyhexamethylene isophthalamide copolymer (nylon 66 /
6I), polyhexamethylene adipamide / polyhexamethylene isophthalamide / polycaproamide copolymer (nylon 66 / 6I / 6), polyhexamethylene adipamide / polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 6
6 / 6T / 6I), polyhexamethylene terephthalamide / polyhexamethylene isophthalamide copolymer (nylon 6T / 6I), polyhexamethylene terephthalamide / poly (2-methylpentamethylene) terephthalamide copolymer (nylon 6T / M5T), Polyhexamethylene terephthalamide / polyhexamethylene sebacamide / polycaproamide copolymer (nylon 6T
/ 610/6), polyhexamethylene terephthalamide / polydodecane amide / polyhexamethylene adipamide copolymer (nylon 6T / 12/66), polyhexamethylene terephthalamide / polydodecane amide / polyhexamethylene isophthalamide copolymer (nylon 6T / 12 / 6I), polyxylylene adipamide (nylon XD6) and mixtures or copolymers thereof.

Particularly preferred are nylon 6, nylon 66, nylon 6/66 copolymer, nylon 610 and nylon 66 / 6I / 6 copolymer,
And nylon 6T / 66 copolymer, nylon 6T
/ 6I copolymer, nylon 6T / 6 copolymer, nylon 6T / 12 copolymer, nylon 6T / 12/66
It is at least one polyamide selected from copolymers and copolymers having hexamethyleterephthalamide units such as nylon 6T / 12 / 6I copolymer. It is also practically preferable to use these polyamide resins as a mixture depending on the required properties such as moldability, heat resistance, toughness and surface property.

The degree of polymerization of the polyamide resin is not particularly limited as long as it can be subjected to ordinary molding processing, but as a relative viscosity measured at 25 ° C. in a 98% concentrated sulfuric acid solution of 1% by weight of the polyamide resin, it is 2 The range of 0.0 to 4.0 is preferable.

The terminal resin of the polyamide resin used in the present invention
There is no particular limitation on the concentration of the radical, but 2 × 10^-Five~ 15x
10^-FiveIt is preferably mol / g, more preferably
Is 3 × 10^-Five~ 12 × 10^-Five, Mol / g, especially preferred
Kuha 5 × 10^-Five~ 10 x 10 ^-FiveIt is mol / g.

The polyamide resin composition of the present invention is characterized in that a plate-shaped aluminum compound is dispersed in the polyamide resin. Here, the aluminum compound may be a compound selected from aluminum oxides, hydroxides and the like such as aluminum oxide, aluminum hydroxide and boehmite. Among them, boehmite is preferable.

The shape of the plate-shaped aluminum compound has an average particle size of 20 to 30 in the polyamide resin composition of the present invention.
0 nm, preferably 50-250 nm, average thickness 1-1
It is necessary that they are dispersed in the form of a plate having a thickness of 0 nm, preferably 1 to 5 nm. Here, being dispersed and present, without aggregation of the plate-shaped aluminum compound,
It is in a state of being dispersed alone or in the polyamide resin as secondary particles having a secondary particle diameter of 0.5 μm or less.
The above-mentioned method for quantifying the dispersed state was carried out by cutting an ultrathin section from a polyamide resin composition, taking a photograph using a transmission electron microscope so that 100 or more plate-shaped aluminum compounds were present in the same visual field, and measuring the same. The shape of each of the plate-shaped aluminum compounds in the field of view is approximated to a quadrangle, and the weight average of the lengths in the long side direction is the average particle size, and the weight average of the lengths in the short side direction is the average thickness. To do.

If the average particle size is less than 20 nm, the effect of improving dimensional stability and heat resistance becomes small, and if it exceeds 300 nm, the toughness tends to decrease, which is not preferable.
On the other hand, if the average thickness is less than 1 nm, it tends to be damaged during molding, so that the effect of improving dimensional stability and heat resistance is poor, and if it exceeds 10 nm, the toughness tends to decrease, which is not preferable.

The content of the plate-shaped aluminum compound contained in the polyamide resin composition of the present invention is not particularly limited, but it is 0.01 to 20% by weight in order to be subjected to plastic working such as extrusion molding and injection molding. Is more preferable, 0.05 to 15% by weight is more preferable, and 0.1 to 10% by weight is further preferable. The content of the plate-shaped aluminum compound in the polyamide resin composition is 600 ° C. for the polyamide resin composition.
It can be obtained from the amount of ash by heating in an electric furnace for 5 hours or more to ash.

The polyamide resin composition of the present invention comprises (A)
It is produced by heating a polyamide-forming monomer, (B) water, and (C) an aluminum source under pressure, and allowing a polymerization reaction of polyamide and a hydrothermal synthesis reaction of a plate-shaped aluminum compound to proceed in the same reaction vessel. be able to. As a result, a composition in which minute plate-shaped aluminum compounds are uniformly dispersed in a polyamide resin, which cannot be achieved by conventional techniques, is achieved. Further, since the aluminum source used as a raw material changes in shape and size by hydrothermal synthesis and is dispersed in the final polyamide resin composition,
It is not always necessary to use an aluminum source having a fine grain size at the raw material stage.

As the polyamide-forming monomer (A), as described in the detailed description of the polyamide resin of the present invention, lactams such as ε-caprolactam, diamines such as hexamethylenediamine and adipic acid, etc. The above dicarboxylic acids can be used. When using diamine and dicarboxylic acid as raw materials, it is preferable to use them as equimolar salts. For example, hexamethylenediamine which is a raw material of nylon 66 and AH salt which is an equimolar salt of adipic acid can be mentioned. It is also possible to use known molecular weight regulators and terminal blocking agents such as monocarboxylic acids and monoamines, or excess diamines and dicarboxylic acids.

The monomer composition preferably has an excess of amine. The excess amine may be an excess of diamine as a monomer component, or the amounts of diamine and dicarboxylic acid may be equivalent and monoamine may be excess. The presence of the amine in excess promotes the formation of a finely dispersed state of the plate-shaped aluminum compound, which is a feature of the present invention. The excess ratio of amine at the start of polymerization is 0.1 to 0.1 as the excess amount of amino terminal groups with respect to all monomer units.
It is preferably 1.0 mol%, and more preferably 0.2 to 0.5 mol%.

The water (B) is an essential component for forming the finely dispersed state of the plate-shaped aluminum compound, which is a feature of the present invention, and ion-exchanged water or distilled water is usually used.

As the aluminum source (C), aluminum oxide, aluminum hydroxide and the like are preferable, and aluminum hydroxide is particularly preferable.

These raw materials are placed in a reaction vessel used for usual pressure polymerization of polyamide and heated under pressure.
Known additives to be added during the polymerization of polyamide, a polymerization catalyst typified by a phosphoric acid compound, an antioxidant, a dyeability improving agent, an inorganic additive such as titanium oxide or talc are features of the present invention. The plate-shaped aluminum compound can be freely used as long as it does not hinder the formation of a dispersed structure of the plate-shaped aluminum compound.

At the stage of starting the pressure polymerization reaction, it is preferable that the charged raw material is in the state of a uniform solution or slurry. For this reason, it is preferable that the raw material is heated in a conditioning tank separate from the polymerization reaction vessel, stirred by a homogenizer or irradiated with ultrasonic waves, and then transferred to the polymerization reaction vessel.

The composition of the charge is such that (A) polyamide-forming monomer is 100 parts by weight, and (B) water is 5 to 30.
0 parts by weight, preferably 10 to 200 parts by weight, more preferably 20 to 100 parts by weight, and the (C) aluminum source is 0.
01 to 30 parts by weight, preferably 0.05 to 20 parts by weight,
It is more preferably 0.1 to 15 parts by weight.

In the reaction, the pressure in the reaction vessel is kept constant by heating the charged composition and discharging water vapor from the reaction vessel so that the pressure becomes 1.5 to 3 MPa, preferably 1.7 to 2.0 MPa. After the step of keeping at, the steam is further released from the system to gradually reduce the pressure, and the maximum attainable temperature is 220 to 330 ° C., preferably 250 to 30 ° C.
The heating temperature is adjusted to be 0 ° C. Further, for the purpose of adjusting the polymerization degree of polyamide as necessary, 220 to
It is also possible to add a step of circulating an inert gas such as nitrogen under normal pressure or reducing the pressure while maintaining the temperature at 330 ° C., preferably 250 to 300 ° C. The above polymerization reaction may be carried out in a single reaction vessel or may be carried out by connecting a plurality of reaction vessels.

Finally, the polyamide resin composition is discharged from the reaction vessel. At this time, the shape of the polyamide resin composition is not particularly limited, but it is usually pelletized by a known pelletizing device such as a strand cutter so that the subsequent processing is convenient.

The polyamide resin composition thus obtained contains, if necessary, unreacted monomers and low-polymerization products extracted with a solvent such as hot water or reduced pressure in the molten state to reduce unreacted monomers and low-polymerization products. For post-treatment such as removal of molecular weight substances, and to further increase the degree of polymerization of polyamide,
It is also possible to use an apparatus for increasing the degree of polymerization in a molten state called solid phase polymerization or a finisher.

In the polyamide resin composition of the present invention, other components such as antioxidants and heat stabilizers (hindered phenol type, hydroquinone type, phosphite type and substitution products thereof) are used as long as the effects of the present invention are not impaired. Etc.), weathering agents (resorcinol-based, salicylate-based, benzotriazole-based, benzophenone-based, hindered amine-based, etc.),
Release agents and lubricants (montanic acid and its metal salts, their esters, their half esters, stearyl alcohol, stearamide, various bisamides, bisurea, polyethylene wax, etc.), pigments (cadmium sulfide, phthalocyanine, metallic pigments, etc.), dyes ( Nigrosine, etc.), crystal nucleating agent (talc, silica, kaolin, clay, etc.), plasticizer (octyl p-oxybenzoate, N-butylbenzenesulfonamide, etc.), antistatic agent (alkylsulfate-type anionic antistatic agent, Quaternary ammonium salt type cationic antistatic agents, nonionic antistatic agents such as polyoxyethylene sorbitan monostearate, betaine amphoteric antistatic agents, etc., flame retardants (red phosphorus, melamine cyanurate, magnesium hydroxide) , Hydroxides such as aluminum hydroxide, polyphosphorus Ammonium, brominated polystyrene, brominated PPO, brominated PC, brominated epoxy resin or combination of these brominated flame retardants with antimony trioxide), inorganic filler, other polymers (polyester, polycarbonate, polyphenylene ether) , Polyphenylene sulfide, polyether sulfone, AB
S resin, SAN resin, polystyrene, acrylic resin, polyethylene, polypropylene, SBS, SEBS, various elastomers, etc.) can be added.

The thermoplastic resin composition of the present invention is extruded,
A molded product can be easily obtained by a usual processing method such as injection molding. The obtained molded product has the same surface appearance and tensile elongation as non-reinforced polyamide resin, and is excellent in dimensional stability and rigidity, and is suitable for various engineering parts and structural materials.

[0029]

The present invention will be described in detail below with reference to examples, but the gist of the present invention is not limited to the following examples.

Evaluation Items and Measuring Method Polymerization degree of polyamide resin: Relative viscosity was measured in 98% concentrated sulfuric acid at 25 ° C. and a concentration of 1% by weight.

Filler component: Wide-angle X-ray diffraction measurement was performed on the molded piece used for the tensile test, and the filler was identified from the diffraction peak pattern.

Ash content of filler: The polyamide resin composition was ashed in an electric furnace at 600 ° C. for 5 hours, and the content was determined by the inorganic ash content.

Shape of filler: An ultrathin section was cut out from a molded piece used for a tensile test, and a photograph of 100 or more fillers in the same visual field was taken with a transmission electron microscope. The weight average of the particle diameter and the thickness of all the fillers reflected in the photograph was calculated using the image analysis device.

Dispersion state of filler: Using the photograph used for measuring the shape of the filler, the presence or absence of aggregates of the filler was observed and evaluated as follows.

⊚: No agglomerates are seen and they exist in a dispersed state.

◯: Dispersed and present as secondary particles having a diameter of 0.5 μm or less.

Δ: Agglomerates having a diameter of 0.5 μm are present in part.

X: Most of them are aggregated and present. Tensile test: Measured according to ASTM D638. The test piece used is an ASTM No. 1 test piece having a thickness of 1/8 inch. The measurement was carried out at 23 ° C.

Bending test: Measured according to ASTM D790. The test pieces used were 1/2 inch x 5 inch x 1 /
It is a 4-inch rod-shaped test piece. The measurement was performed at 23 ° C and 90 ° C.

Linear expansion coefficient: A test piece having a size of 3 × 3 × 10 mm was cut out from the central longitudinal direction of the molded piece used for the tensile test, and 2 ° C./m from 30 ° C. to 100 ° C. was cut using TMA.
The dimensional change when the temperature was raised at a rate of in was measured.

Surface appearance: 80 × 80 × 3 (mm) mirror-polished square plate was injection-molded, and the sharpness of the reflection image of the fluorescent lamp was visually observed on the surface of the obtained square plate and evaluated as follows. .

⊚: Glossy, the reflected image of the fluorescent lamp is clearly observed.

◯: Although glossy, the reflection image of the fluorescent lamp is slightly unclearly observed.

Δ: Slight gloss, but the reflected image of the fluorescent lamp cannot be observed.

X: There is no gloss and no reflection image of the fluorescent lamp can be observed. Example 1 100 parts by weight of AH salt, 0.22 of hexamethylenediamine
Parts by weight, 70 parts by weight of deionized water, and 0.4 parts by weight of aluminum hydroxide (first-grade reagent) are heated to 80 ° C. in a control tank and stirred with a homogenizer to form a uniform slurry,
I put it in an autoclave. The excess ratio of amino terminal groups at the time of charging was 0.5 mol% with respect to the AH salt. The heater temperature is 295 ° C and the pressure inside the can is 1.7M.
After reaching Pa, the pressure was kept constant. After maintaining in this state for 2 hours, the pressure was gradually returned to normal pressure over 1 hour, and further reacted at 280 ° C. for 5 minutes under a reduced pressure of 600 mmHg absolute pressure to complete the polymerization.

The polyamide resin composition after polymerization was discharged in a gut form from the autoclave and pelletized. The obtained pellets were dried and then molded with an injection molding machine having a cylinder temperature of 280 ° C. and a mold temperature of 80 ° C., and evaluated. By X-ray diffraction, 2θ = 14.56 deg and 28.28 deg
A diffraction peak appeared on the surface, confirming the formation of boehmite. Other evaluation results are shown in Table 1. Examples 2 to 4 Polymerization, molding and evaluation were carried out in the same manner as in Example 1 except that the addition amount of aluminum hydroxide was changed. The results are shown in Table 1. Examples 5 and 6 Polymerization, molding and evaluation were carried out in the same manner as in Example 3 except that the charged water content was changed. The results are shown in Table 1.

Comparative Example 1 97 parts by weight of nylon 66 resin of ηr2.7 was mixed with plate boehmite having an average particle size of 1.5 μm and melted by a co-rotating twin-screw extruder having a cylinder temperature of 280 ° C. Kneading was performed. From the X-ray diffraction of the obtained polyamide resin composition, it was found that the boehmite used as a raw material was present in the composition as it was. Molding evaluation was performed in the same manner as in Example 1, and the results are shown in Table 2. Compared with Example 3 in which the amount of inorganic ash was the same, the tensile strength / elongation and flexural modulus were small, and the linear expansion coefficient was large. Furthermore, the surface appearance is inferior.

Comparative Example 2 Melt kneading, molding and evaluation were carried out in the same manner as in Comparative Example 1 except that plate-shaped boehmite having an average particle size of 2 μm was used as a raw material. The results are shown in Table 2. After all, as compared with Example 3 in which the amount of inorganic ash is the same, the tensile strength / elongation and elastic modulus are low and the linear expansion coefficient is large. Furthermore, the surface appearance is inferior.

Comparative Example 3 88 parts by weight of nylon 66 resin and 1 boehmite were used.
Melt kneading, molding and evaluation were performed in the same manner as in Comparative Example 1 except that the amount was 2 parts by weight. The results are shown in Table 2. The elastic modulus at room temperature was the same as in Example 3, but the amount of boehmite compounded to obtain the same elastic modulus was large, and mechanical properties other than the bending elastic modulus and the surface appearance were inferior.

Comparative Example 4 The nylon 66 resin itself used in Comparative Example 1 was molded and evaluated. The results are shown in Table 2. The surface appearance and tensile elongation are excellent, but the flexural modulus is lower than in the examples, the linear expansion coefficient is large, and the dimensional stability is poor.

[0051]

[Table 1]

[0052]

[Table 2]

[0053]

As described above, the polyamide resin composition obtained by the present invention has the same surface appearance and tensile elongation as the non-reinforced polyamide resin, but has a tensile strength, a bending elastic modulus, and a linear expansion coefficient. Since it has an excellent coefficient, it can be widely used as a material for which surface appearance and toughness are required and strength and dimensional stability are required, for example, automobile parts, building materials, furniture parts, and electrical parts.

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 4J001 EA06 EA08 EA15 EA16 EA17                       EA28 EB04 EB05 EB06 EB08                       EB09 EB14 EB34 EB36 EB37                       EC04 EC07 EC08 EC09 EC14                       EC47 EC48 EE08E FD05                       JA04 JA05                 4J002 CL001 CL011 CL031 DE146                       FA016 GL00 GN00 GQ00

Claims (6)

[Claims] 1. A polyamide resin composition comprising a polyamide resin and a plate-shaped aluminum compound dispersed therein, wherein the plate-shaped aluminum compound has an average particle diameter of 20 to 300 nm. And a polyamide resin composition having an average thickness of 1 to 10 nm dispersed therein. 2. The polyamide resin composition according to claim 1, wherein the aluminum compound is boehmite. 3. A polyamide-forming monomer (A), (B)
The polyamide resin according to claim 1 or 2, which is obtained by heating water and an aluminum source (C) under a pressurized condition to allow a polyamide polymerization reaction and a hydrothermal synthesis reaction of a plate-shaped aluminum compound to proceed in the same reaction vessel. Composition. 4. The polyamide resin composition according to claim 3, wherein the aluminum source (C) is aluminum hydroxide. 5. (A) Polyamide-forming monomer, (B)
The water and the aluminum source (C) are heated under a pressure condition to allow the polymerization reaction of the polyamide and the hydrothermal synthesis reaction of the plate-shaped aluminum compound to proceed in the same reaction vessel. Method for producing polyamide resin composition. 6. The method for producing a polyamide resin composition according to claim 5, wherein the composition of the polyamide-forming monomer is amine excess.