KR100580033B1 - Polyamide composition - Google Patents

Abstract

The present invention relates to a polyamide resin composition having excellent thin film fluidity, and more particularly, to a crystalline polyamide resin, by adding a polyamide copolymer, ethylene wax grafted with maleic anhydride, and an inorganic filler, thereby providing a trace of flow on a painted surface. Surface properties are improved, such as reduced anisotropy after molding, reduced coating properties, improved paint adhesion properties, improved rigidity such as flexural modulus, and excellent thermal fluidity. It is about.

Polyamide, Thin Film Fluidity

Description

Polyamide resin composition excellent in thin film fluidity {POLYAMIDE COMPOSITION}

The present invention relates to a polyamide resin composition having excellent thin film fluidity, and more particularly, to a crystalline polyamide resin, by adding a polyamide copolymer, ethylene wax grafted with maleic anhydride, and an inorganic filler, thereby providing a trace of flow on a painted surface. Surface properties are improved, such as reduced anisotropy after molding, reduced coating properties, improved paint adhesion properties, improved rigidity such as flexural modulus, and excellent thermal fluidity. It is about.

Recently, in the case of automobile parts, electric / electronic parts, and industrial parts, research on substitution with plastics has been actively conducted in the direction of satisfying both functional and consumer needs at the same time.

Among these plastic substitutes, polyamide resin is well known as a material sufficient to satisfy the functionality and consumer's desires. Functionality has excellent advantages such as rigidity, toughness, abrasion resistance, electrical properties, chemical resistance, and reinforcing agent addition effect. The surface is beautiful.

However, in the case of the polyamide resin described above, amide stability (-CO-NH-) causes poor dimensional stability due to moisture absorption, whitening, bubbles, etc. during molding, high molding shrinkage rate, and heat shrinkage during secondary processing. There is a disadvantage.

However, by improving the above disadvantages of the polyamide resin, polyamide resin is widely applied to various fields of automobiles, electrical / electronics, and various industrial fields as engineering plastics, and its use is also showing a rapid increase rate. Among these many applications, especially the engine cover part, which is a large injection molding product, should have a good surface during molding and also have excellent secondary workability such as coating characteristics.

In the case of painting properties, the lack of paint adhesion presents a fatal defect in product appearance. In addition, the inorganic material is filled and solved to maintain the dimensional stability of the product. However, when it is added, the economical efficiency is excellent, but the fluidity and coating properties are deteriorated, and the appearance surface is not satisfactory.

On the other hand, the modified polyphenylene oxide described in US Pat. No. 4,923,924, UK Pat. No. 295,103, etc. as a method proposed to improve the surface properties, rigidity, paintability, shrinkage anisotropy of the molded article of the polyamide resin as described above The resin composition is excellent in paintability at room temperature, but when the resin composition is applied to the engine cover, there is a disadvantage that the product is deformed due to lack of chemical resistance and long-term heat resistance, and the surface becomes poor when reinforcing glass fiber to solve this problem. There is this.

In addition, the technology characterized by the amorphous polyamide resin described in US Pat. Nos. 2,696,482, 3.597.400, etc., satisfies the impact resistance and stiffness, but is expensive and when the inorganic material claimed in the present invention is reinforced during molding, the amorphous polyamide The viscosity of the amide resin is high, the surface is poor, there is a problem that the coating adhesion is poor.

Meanwhile, Japanese Patent Application Laid-Open No. 58-17440 discloses a method of improving rigidity, heat resistance and paintability by reinforcing minerals such as talc, cray, and mica among inorganic materials in polyamide resin. Although well-known in Japanese Patent Application Laid-Open No. 60-47063, there is a problem in that the surface characteristics are not excellent in large molded articles.

In addition, alloy to acrylonitrile butadiene styrene resins, which are referred to as polyamide resins and amorphous polymers, are described in US Patent Nos. 509,557, Japanese Patent Application Laid-Open No. 2,173,142, and European Patent 21005. In the above case, due to the lack of compatibility between the polyamide resin and acrylonitrile butadiene styrene resin, the use of a compatibilizer called a third substance is not preferable due to the decrease in weather resistance and rigidity, and the manufacturing cost is increased and it is uneconomical. to be.

As a result of closely examining the prior art as described above, there is a limit to satisfy all the desired stiffness, adhesion during coating, shrinkage anisotropy, surface beauty characteristics, and the like in the present invention. there was,

Accordingly, the inventors of the present invention have made efforts to solve the above problems, and based on polyamide 6 resin, polyamide copolymer resin having a specific crystallization temperature and ethylene wax grafted with a certain amount of maleic anhydride are used. By controlling the crystallization rate, it solved the problem of surface defects such as mineral release on the surface generated during product molding, and it was found that the coating adhesion can be improved and the stiffness and shrinkage anisotropy can be significantly improved. The invention was completed.

Accordingly, an object of the present invention is to provide a polyamide resin composition having improved thin film fluidity having excellent surface properties and strength.

45 to 75% by weight of the polyamide 6 resin; 10 to 30% by weight of polyamide copolymer resin; It is characterized by a polyamide resin composition comprising 0.5 to 3% by weight of maleic anhydride graft ethylene wax and 10 to 25% by weight of an inorganic filler.

This invention will be described in detail.

According to the present invention, by adding a polyamide copolymer, ethylene wax grafted with maleic anhydride, and an inorganic filler to the crystalline polyamide resin, the surface characteristics are improved, such as the flow marks on the painted surface and the shrinkage anisotropy after molding. The present invention relates to a polyamide resin composition having excellent thin film fluidity with improved coating properties, improved coating properties, rigidity such as flexural modulus, and improved thermal stability.

Hereinafter, it demonstrates in detail for every component which comprises the polyamide resin composition of this invention.

The first component is a polyamide 6 resin in the crystalline polyamide resin, which may be used in the range of -NHCO- (CH ₂ ) ₅ -repeating unit in the range of 500 to 15,000, and in a conventional manner, agitator, heat sensor, temperature controller and steam. The reflux cooler uses a product manufactured using an autoclave device for polymerization of polyamide resin, which is a device capable of circulating water, and the production method and the limitation of the production device have no special meaning in the implementation of the technical idea of the present invention. .

A specific method for producing such a polyamide 6 resin will be described by way of example. First, with respect to 100 parts by weight of caprolactam, 7 to 7.5 parts by weight of water, 0.003 to 0.005 parts by weight of the foam inhibitor, and tris- (2.4-diter, which is a heat resistant agent). Iganox B 1171 (available from Ciba Gage) with 1: 1 blend of sheryl butylphenyl) -phosphite and N-N'-hexamethylene bis (3.5-dibutyl butyl-4-hydroxy-hydrocinamide) The polyamide 6 resin can be prepared by adding 0.08 to 0.1 parts by weight to react.

On the other hand, the polyamide 6 resin that can be used in the present invention is preferably a relative viscosity of 2.4 to 2.8 (20 ℃, a solution containing 1 g of polyamide 6 in 100 ml of 96% sulfuric acid). If the viscosity of the polyamide 6 resin to be used is lower than the above range, the rigidity and heat resistance are lowered. If the viscosity of the polyamide 6 resin is exceeded, the high viscosity is accompanied by overpressure during molding, and the surface of the molded article becomes poor and it is difficult to add inorganic materials. Not desirable

In the present invention, it is preferable to make the polyamide 6 resin prepared as described above in the form of a chip and to dry it for about 5 hours at about 90 ° C. in a dehumidifying dryer.

The polyamide 6 resin is used in the 45 ~ 75% by weight, if the amount is less than the above range relatively high content of copolymer polyamide, ethylene wax, inorganic filler, poor surface, the rigidity is lowered if the above range is exceeded This is undesirable.

As the second component, polyamide copolymer resin is used.

The polyamide copolymer resin may be lactam, aminocarboxylic acid or a mixture thereof; Salts containing diamines and dicarboxylic acids; And dicarboxylic acids having 75 to 85: 10 to 15: 5 to 10 weight ratios, respectively.

The same diamine can be illustrated.

The lactam may be used to prepare a polyamide homopolymer, and specifically, for example, one selected from caprolactam, lauryllactam, enanthactam, α-pyrrolidone, α-piperidone and the like may be used. Can be.

The aminocarboxylic acid is selected from 6-aminohexanoic acid, 7-aminoheptanoic acid, 12-aminododecanoic acid, p-aminocyclohexylcarboxylic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, and 6-aminocaproic acid. You can use the selected one. The polyamine is methaxylenediamine, paraxylenediamine, hexamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1,3-bisaminomethylcyclohexane, bis- p-aminocyclohexylmethane, tetramethylene diamine, nonamethylenediamine, undecamethylene diamine, dodecamethylenediamine and the like can be used.

The polycarboxylic acid may be adipic acid, sebacic acid, schweric acid, pimelic acid, isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, glutaric acid, azelaic acid, undecaedionic acid, dodecadioic acid hexadecadionic acid, Hexadecenedioic acid, icodic acid dioic acid, icodic acid dienoic acid, diglycolic acid, 2,2,4-trimethyladipic acid, xylenedicarboxylic acid, 1,4-cyclohexane and 2,2,4-trimethyladipic acid And the like can be used.

The polyamide copolymer is prepared by the conventional method by selecting from the above-mentioned components, and the apparatus used may be the same apparatus as the one used in the production of the polyamide 6 resin, and the selection of such a manufacturing method and manufacturing apparatus and The limitation does not have particular meaning in the implementation of the technical idea of the present invention.

For example, a specific method of preparing such a polyamide copolymer resin is first introduced into a stirrer, and a diamine such as hexamethylenediamine and a dicarboxylic acid such as adipic acid are added in a 20:80 weight ratio. In this case, the salt may be 10 to 15% by weight in the polyamide copolymer. To this, add 5 to 8% by weight of dicarboxylic acid such as isophthalic acid, add 6 to 7% by weight of water, stir to dissolve while raising the temperature, and add 0.015% by weight of trace phosphoric acid and 0.015% by weight of antifoam. do. Here, 0.08% by weight of Iganox B1171 (Siba Gaji Co., Ltd.) was added as a heat-resistant agent to prepare the conditions shown in Table 1 below, where the reduced pressure and vacuum can be controlled by administering nitrogen. As the copolymer, polyamide copolymer resin is prepared through a discharging process,

step Pressure (Kg / cm ² ) Temperature (℃) Hours (minutes) Temperature rise Normal pressure → 15 120 → 265 60 Suppression 15 days 265 maintenance 30 Decompression Atmospheric pressure 265 → 255 90 Atmospheric pressure Atmospheric pressure 255 → 265 30 vacuum -360 mmHg 265 maintenance 60

Preferably, the polyamide copolymer resin prepared above has a relative viscosity of 2.8 to 4.0 (20 ° C., a solution containing 1 g of polyamide copolymer resin in 100 ml of 96% sulfuric acid). At this time, when the viscosity of the polyamide copolymer resin used is less than the above range, there is no effect of surface improvement in the final composition, when the viscosity exceeds the above range, the alloy efficiency is lowered when kneading with the polyamide 6 resin and molded It is accompanied by an increase in viscosity, there is a disadvantage that the surface defects or lack of coating adhesion due to the addition of inorganic materials.

The polyamide copolymer resin is preferably made into chips and dried for about 5 hours at about 90 ° C. in a dehumidifying dryer.

In addition, in the case of the polyamide copolymer resin used in the present invention using a thermal analyzer (trade name, PERKIN ELMER DSC7) 280 The crystallization temperature measured after the temperature drop to -20 ℃ / min after 1 minute at ℃ ℃ 135 ~ 155 ℃ to use, in this case, if the crystallization temperature is less than 135 ℃ post-shrink occurs in the post-molding process after molding If the crystallization temperature exceeds 155 ℃, the crystallization rate is fast, the appearance of the molded product is poor and the coating properties are poor, there is a disadvantage that the addition effect can not be obtained.

Such polyamide copolymer resin is used in the polyamide resin composition of the present invention 10 to 30% by weight, when the amount is less than 10% by weight is rapidly solidified during molding, the surface is not good, when the amount is more than 30% by weight The disadvantage is that post-shrinkage occurs after molding.

As a third component, maleic anhydride graft ethylene wax is used.

In the present invention, ethylene wax and maleic anhydride are grafted at a weight ratio of 98 to 99.8: 0.2 to 2. At this time, if the maleic anhydride content is less than the above range, the compatibility is poor due to the decrease in reactivity with polyamide, resulting in poor physical properties and coating properties, and if the maleic anhydride content is above the above range, it exhibits further effects in relation to the reaction. In addition, since the gas is generated, the surface of the molded article is not good.

The maleic anhydride graft ethylene wax is used in the range of 0.5 to 3% by weight of the total polyamide resin composition, when the amount is less than the above range, the flow characteristic effect is insignificant, and the polarity that can be combined with the coating material during coating It is not desirable to obtain good coating properties, and if the amount of use exceeds the above range, the processing temperature of the polymer is high and the amount of gas generated during molding is high due to thermal stability problems at high temperatures, which is not preferable because the surface is not good.

As a fourth component, an inorganic filler is used.

The inorganic filler should be selected to maintain the ratio (L / D) of the length and diameter in the proper line. In other words, the length and diameter ratio (L / D) of 10 to 50 to use, where the length and diameter ratio (L / D) of less than 10 does not have a good effect on the physical properties, more than 50 It has a drawback that the micro-expression phenomenon occurs on the surface during molding, poor paint adhesion, or the surface state is not beautiful and the shrinkage anisotropy is large,

Such inorganic fillers may be selected from silica, graphite, silicate compounds, talc, ulastonite, cray, calcium carbonate, barium sulfate, alumina, mica, and the like, and most preferably, ulastonite having a needle structure. That is, it is most preferable to use needle-shaped urastonite having a ratio (L / D) of length to diameter of 10 to 50.

The inorganic filler is used 10 to 25% by weight of the total polyamide resin composition, preferably 15 to 20% by weight, when the amount is less than the above range, the elastic modulus of the basic properties is low, if it exceeds 25% by weight fluidity There is a problem that the surface is rough due to the degradation is not excellent.

In addition, it is possible to select and use the heat stabilizer necessary for the heat stabilizer and the single product in the processing process, which is another material within the scope of not impairing the object of the present invention, which is a long-term heat stabilizer generally added, which is not the main composition in the present invention. .

In the case of the present invention, as a heat resistant agent, I-1010 (brand name, manufacturer: Shiba Gaji), which is a phenol-based hindered amine, was used. Potassium iodide (KI) and copper iodide (CuI), which are metal long-term heat stabilizers, were added.

In addition, the polyamide resin composition of the present invention may be prepared by selecting among devices used to prepare a conventional plastic resin composition. In one embodiment of the present invention, the temperature of the barrel is specifically used by using a coaxial twin screw extruder. It was prepared at 250 ~ 260 ℃, it was the best when the first inlet, polyamide 6 resin, polyamide copolymer resin and heat-resistant agent, and the inorganic filler in the secondary inlet. A pressure reducing device called vent was provided at the tip of the discharge portion, and it was effective to maintain the vacuum degree at 150 mmHg or less.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the following Examples.

Examples 1-6

The polyamide 6 resin and the polyamide copolymer resin were melt kneaded in a twin screw extruder heated to 250 ° C., and then made into a chip state and dried by using a dehumidifying dryer at 90 ° C. for 5 hours. The components of the polyamide resin composition having the composition shown in Table 2 were prepared by using a heated screw-type injection molding machine at 250 ° C. for evaluation specimens and evaluation disc specimens, and the physical properties thereof were measured by the following experimental examples.

 division Polyamide 6 ^{# 1} (% by weight)  Polyamide Copolymer (% by weight) Ethylene Wax (wt%) Woollastonite (wt%) Example 1 69.5 10 ^{# 2} 0.5 ^{# 3} 20 ^{# 4} Example 2 58.5 20 ^{# 2} 1.5 ^{# 3} 20 ^{# 4} Example 3 57.0 30 ^{# 2} 3.0 ^{# 3} 20 ^{# 4-1} Example 4 69.5 10 ^{# 2-1} 0.5 ^{# 3-1} 20 ^{# 4} Example 5 58.5 20 ^{# 2-1} 1.5 ^{# 3-1} 20 ^{# 4-1} Example 6 47.0 30 ^{# 2-1} 3.0 ^{# 3-1} 20 ^{# 4-1} Note: # 1, Polyamide 6: PA6 # 2, Copolymer # 2-1 having a crystallization temperature of 139 ^o C, Copolymer # 3 having a crystallization temperature of 150 ^o C, Maleic anhydride 0.8 parts by weight of grafted ethylene wax # 3-1, 1.5 parts by weight of ethylene wax # 4 grafted ethylene wax # 4, ulastonite # 4-1 with mineral L / D 25, and ulasto with mineral L / D 40 Night

Experimental Example: Measurement of Physical Properties

Physical properties of the following method were measured with the specimen to which the polyamide resin composition prepared according to Examples 1 to 6 was applied, and the results are shown in Table 3 below.

1) Flexural modulus: 6.4mm thickness test piece was manufactured and measured according to ASTM D790.

2) Surface characteristics: It is judged to be good if there is no flowmark or gas expression when visually discerning disc specimens with a gate size of 0.5 ㎝, thickness of 3.2 mm and diameter of 100 mm by visual injection within 1.5 cm around the gate. .

3) Shrinkage anisotropy of molded products: Evaluate the specimen by 3.2mm thickness and 10mm diameter by injection molding and measure the direction of gate and right angle. The ratio of the dimension of the gate direction and the perpendicular direction is calculated by the following Equation 1 below 110% is excellent, and above 110% means defective.

Ratio = Orthogonal / Gate Direction × 100

3) Coating characteristics: Coating adhesion is applied to 100 squares of 1mm × 1mm in width x length by cross-cut method after coating the rectangular specimens with width × length × thickness of 10cm × 10cm × 0.3cm. The OPP tape, which was made and sold on the market, was bonded to the entire compartment, and when the tape was removed after 5 seconds, the number of compartments separated by the tape from the 100 compartments (mean value after five evaluations) was measured. In this case, the smaller the number of spaces apart, the better the adhesion between the resin and the coating agent. If the value is 5 or less, it is very good, 6 to 15 is relatively good, and if it exceeds 15, a bad level is indicated.

division Flexural modulus (kg / cm ² ) surface Shrinkage anisotropy (%) Paintability Example 1 39000 Good 108.1 8 Example 2 38000 Good 106.3 5 Example 3 37000 Good 104.2 0 Example 4 39500 Good 109.1 12 Example 5 38700 Good 107.5 7 Example 6 40500 Good 106.0 3 Shrinkage anisotropy: below 110-good, above 110-poor coating property: below 5-very good, 6 ~ 15-excellent, above 15-poor

Comparative Examples 1 to 15

Next, test specimens were prepared in the same manner as in Examples 1 to 6, using the ingredients and contents shown in Table 4 below.

division Polyamide (wt%) Copolyamide (wt%) Maleic anhydride grafted ethylene wax (% by weight) Mineral (wt%) Talc Cray ^{# 6} Mica ^{# 7} Fiberglass ^{# 9} Ulasto night Comparative Example 1 59.0 20 ^{# 10} 1.0 ^{# 11} 20 ^{# 5} Comparative Example 2 59.0 20 ^{# 10} 1.0 ^{# 11} 20 ^{# 5-1} Comparative Example 3 59.0 20 ^{# 10} 1.0 ^{# 11} 20 Comparative Example 4 59.0 20 ^{# 10} 1.0 ^{# 11} 20 Comparative Example 5 59.0 20 ^{# 10} 1.0 ^{# 11} 20 Comparative Example 6 59.0 20 ^{# 10} 1.0 ^{# 11} 20 ^{# 8} Comparative Example 7 59.0 20 ^{# 10} 1.0 ^{# 11} 20 ^{# 8-1} Comparative Example 8 59.7 20 ^{# 10} 0.3 ^{# 11} 20 ^{# 8-2} Comparative Example 9 56.0 20 ^{# 10} 4.0 ^{# 11} 20 ^{# 8-2} Comparative Example 10 74.0 5 ^{# 10} 1.0 ^{# 11} 20 ^{# 8-2} Comparative Example 11 44.0 35 ^{# 10} 1.0 ^{# 11} 20 ^{# 8-2} Comparative Example 12 59.0 20 ^{# 10} 1.0 ^{# 11-1} 20 ^{# 8-2} Comparative Example 13 59.0 20 ^{# 10} 1.0 ^{# 11-2} 20 ^{# 8-2} Comparative Example 14 59.0 20 ^{# 10-1} 1.0 ^{# 11} 20 ^{# 8-2} Comparative Example 15 59.0 20 ^{# 10-2} 1.0 ^{# 11} 20 ^{# 8-2} Note) # 5, particle size 11 μm talc # 5-1, particle size 5 μm talc # 6, particle size 2 μm cray # 7, particle size 5 μm mica # 8, L / D 8 woollaston # 8- 1, Woollaston # 8-2 with L / D 55, Woollaston # 9 with L / D 25, Glass fiber # 10 with a diameter of 3um, length 3mm, Crystallization temperature 145 ^° C Polyamide copolymer # 10- 1, crystallization temperature 125 ^o C polyamide copolymer # 10-2, crystallization temperature 175 ^o C polyamide copolymer # 11, 1.5% by weight of maleic anhydride grafted ethylene wax # 11-1, 0.1% by weight of maleic anhydride Grafted ethylene wax # 11-2, ethylene wax grafted 3.0% by weight of maleic anhydride

 division Flexural modulus (kg / cm ² ) surface Contraction anisotropy%) Paintability Comparative Example 1 38000 Bad 114.5 30 Comparative Example 2 37000 Bad 108.2 35 Comparative Example 3 30000 Good 105.5 10 Comparative Example 4 31000 Bad 107.1 14 Comparative Example 5 60100 Bad 130.2 70 Comparative Example 6 30500 Good 105.5 14 Comparative Example 7 47000 Bad 120.8 20 Comparative Example 8 39400 Good 108.9 21 Comparative Example 9 39000 Bad 106.5 8 Comparative Example 10 38700 Bad 120.3 8 Comparative Example 11 36000 Good 111.0 25 Comparative Example 12 41000 Bad 106.2 40 Comparative Example 13 39500 Bad 109.9 14 Comparative Example 14 40500 Good 107.4 18 Comparative Example 15 38000 Bad 110.1 20 Shrinkage anisotropy: below 110-good, above 110-poor

As shown in Table 5 above, when the type of the inorganic filler was not limited (Comparative Examples 1 to 5), the surface characteristics were poor, or the rigidity which could be expressed by the flexural modulus was poor or the coating property was bad. In the case of using an inorganic filler having an L / D out of range (Comparative Examples 6 and 7), paintability and stiffness were poor, and when the content of ethylene wax was low (Comparative Examples 8 and 9), paintability and surface properties were poor. The crystallization temperature of the polyamide copolymer resin when the content of the amide copolymer resin is insufficient (Comparative Examples 10 and 11) and when the content of the maleic anhydride grafted on the ethylene wax is low or high (Comparative Examples 12 and 13). Was high or low (Comparative Examples 14 and 15), poor paintability and surface properties.

As described above, the polyamide resin composition of the present invention has excellent surface properties such as no surface expression generated when inorganic material is strengthened on the surface of the product when the coating film is formed, good shrinkage anisotropy after molding, and rigidity (flexural modulus of 33,000). kg / cm ² or more), and the coating adhesion effect is excellent.

The polyamide resin composition of the present invention is applied to the surface of a large injection molding for automotive parts, and has excellent surface properties such as no flow marks such as weld lines and flowmarks on the surface of the product. A beautiful thin film can be formed.

In addition, since there is a feature that can be applied to high temperature parts such as engine cover with excellent thermal stability, there is an effect that can be applied to various industrial fields.

Claims (11)

45 to 75 weight percent of polyamide 6 resin; 10 to 30% by weight of polyamide copolymer resin; A polyamide resin composition comprising 0.5 to 3% by weight of maleic anhydride graft ethylene wax and 10 to 25% by weight of an inorganic filler. The polyamide resin composition according to claim 1, wherein the polyamide 6 resin has a relative viscosity of 2.4 to 2.8 (based on a solution containing 1 g of polyamide 6 in 100 ml of 96% sulfuric acid at 20 ° C). The method of claim 1, wherein the polyamide copolymer resin is lactam, aminocarboxylic acid or a mixture thereof; Salts containing diamines and dicarboxylic acids; And dicarboxylic acids each being a terpolymer composed of 75 to 85:10 to 15:10 to 5-10 weight ratios. 4. The polyamide resin composition according to claim 3, wherein the lactam is selected from caprolactam, lauryllactam, enanthactam, α-pyrrolidone and α-piperidone. 4. The aminocarboxylic acid of claim 3, wherein the aminocarboxylic acid is 6-aminohexanoic acid, 7-aminoheptanoic acid, 12-aminododecanoic acid, p-aminocyclohexylcarboxylic acid, 9-aminononanoic acid, 11-aminoundecanoic acid and 6 Polyamide resin composition, characterized in that selected from aminocaproic acid. The method of claim 3, wherein the multiamine is metaxylenediamine, paraxylenediamine, hexamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, 1,3-bisamino A polyamide resin composition selected from methylcyclohexane, bis-p-aminocyclohexylmethane, tetramethylene diamine, nonamethylenediamine, undecamethylene diamine and dodecamethylenediamine. 4. The method of claim 3, wherein the polycarboxylic acid is adipic acid, sebacic acid, schweric acid, pimelic acid, isophthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, glutaric acid, azelaic acid, undecaendic acid, dodecadi Onmic acid hexadecadiic acid, hexadecenedioic acid, icodic acid ionic acid, icodic acid dienedic acid, diglycolic acid, 2,2,4-trimethyladipic acid, xylenedicarboxylic acid, 1,4-cyclohexane and 2,2 Polyamide resin composition, characterized in that selected from 4-trimethyl adipic acid. The polyamide resin composition according to claim 1, wherein the polyamide copolymer has a crystallization temperature of 135 to 155 ° C. The polyamide resin composition according to claim 1, wherein the maleic anhydride graft ethylene wax is grafted with an ethylene wax and maleic anhydride in a weight ratio of 98 to 99.8: 0.2 to 2, The polyamide resin composition of claim 1, wherein the inorganic filler has a length and diameter ratio (L / D) of 10 to 50. The polyamide resin composition according to claim 10, wherein the inorganic filler is ulastonite.