KR101397703B1 - Polyamide resin, a method for preparing the same, and an article comprising the same - Google Patents

Abstract

The present invention relates to a polyamide resin, a method for producing the same, and articles containing the same. More specifically, the present invention provides a polyamide resin made from an environmentally friendly monomer and excellent in heat resistance, moldability, and dimensional stability, and an article comprising the same.

Description

TECHNICAL FIELD The present invention relates to a polyamide resin, a method for producing the same, and a product comprising the same.

The present invention relates to a polyamide resin, a method for producing the same, and articles containing the same. More specifically, the present invention provides a polyamide resin which is environment-friendly, excellent in moldability, dimensional stability, low water absorption rate, high strength retention rate and gloss, a method for producing the same, and articles containing the same.

Nylon 66 and nylon 6 are best known as polyamide resins. These aliphatic polyamide resins are widely used for automobile parts, electric appliances, electronic products, and machine parts. However, aliphatic polyamide resins do not have sufficient thermal stability to be applied in fields requiring high heat resistance characteristics. The aromatic polyamide resin has a higher melting temperature and higher heat resistance than the aliphatic polyamide resin, but has a limited moldability or processability due to such a high melting temperature.

Thus, there is a need to develop a polyamide resin which solves the problem of insufficient heat resistance of the aliphatic polyamide as a polyamide resin and solves the problem of moldability and workability of the aromatic polyamide resin at the same time.

On the other hand, conventionally, a polyamide resin has been produced by limiting the reactants induced by chemical synthesis such as aliphatic diamines, aromatic dicarboxylic acids, and aromatic diamines. This can cause problems with the supply and demand of reactants, including environmental pollution problems. However, recently, as interest in the environment has been amplified, attempts have been actively made to synthesize polyamide resins from environmentally friendly reactants rather than merely chemical reactions.

It is an object of the present invention to provide an environmentally friendly polyamide resin.

Another object of the present invention is to provide a polyamide resin excellent in heat resistance, moldability and dimensional stability.

Another object of the present invention is to provide a polyamide resin having a low moisture absorption rate and high strength retention and high gloss.

It is still another object of the present invention to provide a method for producing the polyamide resin.

It is still another object of the present invention to provide an article molded from the polyamide resin or the polyamide resin produced by the method.

A polyamide resin which is one aspect of the present invention is formed by the polymerization of (A) an aromatic dicarboxylic acid monomer, (B) itaconic acid and (C) an aliphatic diamine monomer and has a total molar number of (A) + The ratio (C) / ((A) + (B)) of the number of moles of (C) can be 0.98-1.02.

Another aspect of the present invention is a method for producing a polyamide resin, which comprises polymerizing a mixture of (A) an aromatic dicarboxylic acid monomer, (B) itaconic acid and (C) an aliphatic diamine monomer, The ratio (C) / ((A) + (B)) of the number of moles of (C) to the total number of moles of the compound (B) may be 0.98-1.02.

The article, which is another aspect of the present invention, can be formed of a polyamide resin or a polyamide resin produced by the above-mentioned production method.

The present invention provides a polyamide resin that is environmentally friendly, has excellent heat resistance, moldability, dimensional stability, low water absorption, high strength retention, and high gloss.

A polyamide resin which is one aspect of the present invention may be formed by polymerization of (A) an aromatic dicarboxylic acid monomer, (B) itaconic acid and (C) an aliphatic diamine monomer. In addition to the components (A), (B) and (C), the polyamide resin may further contain an aliphatic dicarboxylic acid monomer, an aromatic diamine monomer, or a mixture thereof (D), which is a monomer commonly used in the production of a polyamide resin, .

In the present specification, the "monomer mixture for polyamide resin" may mean (A) + (B) + (C) or (A) + (B) + (C) + (D).

In one embodiment, the polyamide resin may be formed by polymerization of (A) an aromatic dicarboxylic acid monomer, (B) itaconic acid, and (C) an aliphatic diamine monomer.

The ratio (C) / (A) + (B) of the number of moles of (C) to the total number of moles of the sum of the aromatic dicarboxylic acid monomer (A) and the itaconic acid (A) ) Can be 0.98-1.02. When the molar ratio is less than 0.98 or more than 1.02, the number of the terminal dicarboxylic acid and diamine becomes relatively large, which may cause discoloration of the resin during the melt processing, which may hinder the formation of molecular weight of the resin and cause problems in moldability. Preferably, the ratio of the number of moles of (C) / ((A) + (B)) can be 0.99-1.018, more preferably 1.010-1.014.

(B) Itaconic acid is a bio-derived monomer which can be obtained from a decarboxylation action of sugar or a culture medium of bacteria, and makes it possible to produce an environmentally friendly polyamide resin.

(B) itaconic acid may be contained in 10 mol% or more of the monomer mixture for polyamide resin. Within this range, the aromatic dicarboxylic acid monomer and the aliphatic diamine monomer competitively react with each other to form a 5-membered ring in the polyamide resin, thereby increasing the heat resistance of the resin.

Preferably, 10 to 40 mol%, more preferably 10 to 20 mol%, and most preferably 10 to 19.5 mol% of the monomer mixture for polyamide resin can be contained.

The aromatic dicarboxylic acid monomer (A) may be an aromatic dicarboxylic acid monomer having 6 to 20 carbon atoms. Specific examples include terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 1,4- , 3-phenylenedioxydiacetic acid, diphenic acid, 4'4'-oxybis (benzoic acid), diphenylmethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4'dicarboxylic acid, 4,4'-diphenylcarboxylic acid, or a mixture thereof. Preferably an aromatic dicarboxylic acid monomer having 8 to 20 carbon atoms, more preferably terephthalic acid or a mixture containing terephthalic acid.

The aromatic dicarboxylic acid monomer (A) may be contained in an amount of 20 mol% or more in the monomer mixture for polyamide resin. Within the above range, excellent heat resistance can be obtained. Preferably 30 to 40 mol%, and more preferably 30 to 39.5 mol%.

(C) The aliphatic diamine monomer needs to have an appropriate number of carbon atoms in order to increase the reactivity to the peanut condensate and to produce the polyamide resin having high heat resistance by an additional internal reaction. Preferably, one or more of linear or side-chain aliphatic diamines having 4 to 10 carbon atoms can be selected. Specific examples thereof include aliphatic diamines such as 1,4-butanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,10-decanediamine, 1,6-hexanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, ), Bis (3-aminopropyl) ether, ethylene glycol bis (3-aminopropyl) ether (EGBA), 1,7-diamino-3,5-dioxoheptane or mixtures thereof. It does not. Preferably, as the aliphatic diamine having 4 to 6 carbon atoms, 1,6-hexanediamine or a mixture containing it can be used.

(C) The aliphatic diamine monomer may be contained at 20 mol% or more in the monomer mixture for polyamide resin. Within the above range, heat resistance and molding processability can be obtained. , Preferably 20-60 mol%, more preferably 50-60 mol%, and most preferably 50-55 mol%.

In another embodiment, the polymerization of the polyamide resin may further comprise monomer (D) in addition to (A), (B) and (C). For example, the monomer (D) may include an aliphatic dicarboxylic acid monomer, an aromatic diamine monomer, or a mixture thereof. These may be contained at 0.5-10 mol% in the monomer mixture for polyamide resin.

Examples of the aliphatic dicarboxylic acid monomer include aliphatic dicarboxylic acid monomers having 4-14 carbon atoms such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, Dioxanic acid, glutaric acid, traumatic acid, succinic acid, and the like, but is not limited thereto.

The aromatic diamine monomer may be an aromatic diamine monomer having 6 to 20 carbon atoms, for example, methylene dianiline, phenylenediamine, and the like, but is not limited thereto.

The polyamide resin may be encapsulated with an end capping agent whose terminal group is selected from aliphatic carboxylic acids or aromatic carboxylic acids. The endblocking agent may be selected from the group consisting of acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, ? -naphthalenecarboxylic acid,? -naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, and the like can be used, but are not limited thereto.

The end-capping agent may be contained in an amount of 0 to 5 mol%, preferably 0.001 to 3 mol%, based on 100 mol% of the monomer mixture for polyamide resin.

The glass transition temperature of the polyamide resin can be 100-130 占 폚. Within the above range, high heat resistance can be ensured. Preferably 110-130 < 0 > C.

The polyamide resin may have an intrinsic viscosity [?] Of 0.3-4.0 dL / g, preferably 0.77-1.1 dL / g, as measured by a 97% sulfuric acid solution and a Ubbelodhde viscometer at 25 ° C.

The polyamide resin may have a water absorption rate of 2.0% or less, preferably 1.1 to 1.8% after being treated at 50 DEG C and RH 90% for 48 hours.

The water absorption rate is 100 mm in length, 100 mm in width, and 3 mm in thickness, and vacuum dried at 120 ° C for 4 hours. The weight (W ₀ ) of the dried specimen is measured. The dried specimens are treated in a thermo-hygrostat at 50 ° C and 90% RH for 48 hours and the weight (W ₁ ) of the specimens is measured. The water absorption rate is calculated according to the following formula.

Water Absorption Rate (%) = | W ₁ -W ₀ | / W ₀ * 100

The polyamide resin may have a strength retention ratio of 92% or more, preferably 92 to 95%.

The strength retention ratio is determined by measuring the ratio of tensile strength after treatment to tensile strength before treatment at 80 ° C and 95% relative humidity for 24 hours in a thermo-hygrostat. Tensile strength is measured according to ISO 527 (23 캜, 5 mm / min).

The polyamide resin may have a brightness of 92 or more, preferably 92 to 94. [

Brightness measures the L * value using a colorimeter based on the criteria defined in ASTM D 1209.

A method for producing a polyamide resin, which is another aspect of the present invention, may comprise polymerizing a monomer mixture for a polyamide resin comprising (A) an aromatic dicarboxylic acid monomer, (B) itaconic acid and (C) an aliphatic diamine monomer have.

The ratio (C) / (A) + (B) of the number of moles of (C) to the total number of moles of (A) + (B) in the monomer mixture for polyamide resin may be 0.98-1.02. Preferably, the molar ratio can be from 0.99 to 1.018.

The copolymerization can be carried out by a conventional method for producing a copolymer, and a melt polymerization method can be preferably used.

The polymerization temperature is 80 ℃ -300 ℃, and preferably may be a 80 ℃ -280 ℃, the polymerization pressure can be ^{10kgf / cm 2 -40kgf / cm 2} .

In one embodiment, a reactor is filled with a mixture of (A) an aromatic dicarboxylic acid monomer, (B) itaconic acid and (C) an aliphatic diamine monomer, a catalyst and water, and the mixture is stirred at 80-150 DEG C for 0.5-2 hours. The temperature is maintained at 200 to 280 ° C for 2 to 4 hours, the pressure is maintained at 20 to 40 kgf / cm ² , the pressure is reduced to 10 to 20 kgf / cm ^2, and the reaction is performed for 1 to 3 hours. The polyamide thus obtained is solid-state polymerized at a temperature between the glass transition temperature (Tg) and the melting temperature (Tm), for example, 150 to 360 ° C for 5 to 30 hours in a vacuum state, Can be obtained.

A catalyst may be used for the polymerization reaction. Preferably, a phosphorous-based catalyst may be used. Specifically, phosphoric acid, phosphorous acid, hypophosphorous acid or a salt or derivative thereof may be used. As a more specific example, phosphoric acid, phosphorous acid, hypophosphorous acid, sodium hypophosphate, sodium hypophosphonate and the like can be used.

The catalyst is preferably used in an amount of 0-3.0 wt%, preferably 0-1.0 wt%, more preferably 0.0001-0.5 wt%, based on the monomer mixture for polyamide resin.

An end encapsulant may be used when the mixture of (A) an aromatic dicarboxylic acid monomer, (B) itaconic acid and (C) an aliphatic diamine monomer is added. The viscosity of the synthesized polyamide copolymer resin can be controlled by controlling the amount of the end sealant used.

The end-capping agent may be an aliphatic carboxylic acid or an aromatic carboxylic acid. In an embodiment, the end-capping agent is selected from the group consisting of acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, , Toluic acid,? -Naphthalenecarboxylic acid,? -Naphthalenecarboxylic acid, and methylnaphthalenecarboxylic acid. These may be used alone or in combination of two or more.

The end-capping agent may be contained in an amount of 0 to 5 mol%, preferably 0.001 to 3 mol%, based on 100 mol% of the monomer mixture for polyamide resin.

An article which is another aspect of the present invention can be molded with the polyamide resin, or a polyamide resin produced by the production method. For example, it may be applied to electrical and electronic materials such as an LED reflector and plastic joint portions of automobile parts, but is not limited thereto. The article forming method may be any known method.

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

The contents not described here are sufficiently technically inferior to those skilled in the art, and a description thereof will be omitted.

Example  One: Of polyamide resin  Produce

0.19 mol (20.816 g) of terephthalic acid, 98.02 g of terephthalic acid, 20.816 g of itaconic acid, 0.76 mol of 1,6-hexamethylenediamine, 0.023 mol (1.35 g) of acetic acid, ) And 139.34 mL of water were charged in a 1 liter autoclave and filled with nitrogen. After stirring at 100 ℃ 60 minutes and warmed for 2 hours at 250 ℃ while maintaining 25kgf / cm ² it was allowed to react for 3 hours at this temperature. The pressure was reduced to 15 kgf / cm < ² >, and the reaction was conducted for 1 hour to prepare a polyamide prepolymer. The prepared polyamide prepolymer was subjected to solid phase polymerization at 230 DEG C for 24 hours to obtain a polyamide resin.

Example  2: Of polyamide resin  Produce

0.225 mol (29.27 g) of terephthalic acid, 87.22 g of terephthalic acid, 29.27 g of itaconic acid, 0.76 mol of 1,6-hexamethylenediamine, 0.027 mol of acetic acid (1.62 g) and 0.1 wt% ) And 137.90 mL of water were placed in a 1 liter autoclave and filled with nitrogen. After stirring at 100 ℃ 60 minutes and warmed for 2 hours at 250 ℃ while maintaining 25kgf / cm ² it was allowed to react for 3 hours at this temperature. The pressure was reduced to 15 kgf / cm < ² >, and the reaction was conducted for 1 hour to prepare a polyamide prepolymer. The prepared polyamide prepolymer was subjected to solid phase polymerization at 230 DEG C for 24 hours to obtain a polyamide resin.

Example  3: Preparation of polyamide resin

0.69 mol (76.42 g) of terephthalic acid, 0.29 mol (37.73 g) of itaconic acid, 0.76 mol (88.32 g) of 1,6-hexamethylenediamine, 0.015 mol ) And 135.14 mL of water were charged in a 1 liter autoclave and filled with nitrogen. After stirring at 100 ℃ 60 minutes and warmed for 2 hours at 250 ℃ while maintaining 25kgf / cm ² it was allowed to react for 3 hours at this temperature. The pressure was reduced to 15 kgf / cm < ² >, and the reaction was conducted for 1 hour to prepare a polyamide prepolymer. The prepared polyamide prepolymer was subjected to solid phase polymerization at 230 DEG C for 24 hours to obtain a polyamide resin.

Example  4: Of polyamide resin  Produce

0.19 mol (20.816 g) of terephthalic acid, 98.02 g of terephthalic acid, 20.816 g of itaconic acid, 0.7575 mol (88.03 g) of 1,6-hexamethylenediamine, 0.015 mol of acetic acid (0.90 g) ) And 138.75 mL of water were placed in a 1 liter autoclave and filled with nitrogen. After stirring at 100 ℃ 60 minutes and warmed for 2 hours at 250 ℃ while maintaining 25kgf / cm ² it was allowed to react for 3 hours at this temperature. The pressure was reduced to 15 kgf / cm < ² >, and the reaction was conducted for 1 hour to prepare a polyamide prepolymer. The prepared polyamide prepolymer was subjected to solid phase polymerization at 230 DEG C for 24 hours to obtain a polyamide resin.

Comparative Example  1: Preparation of polyamide resin

, 0.225 mol (29.27 g) of itaconic acid, 0.712 mol (82.79 g) of 1,6-hexamethylenediamine, 0.1 wt% of sodium hyphaphosphinate (0.20 g) and 132.86 mL of water, It was placed in an autoclave and filled with nitrogen. After stirring at 100 ℃ 60 minutes and warmed for 2 hours at 250 ℃ while maintaining 25kgf / cm ² it was allowed to react for 3 hours at this temperature. The pressure was reduced to 15 kgf / cm < ² >, and the reaction was conducted for 1 hour to prepare a polyamide prepolymer. The prepared polyamide prepolymer was subjected to solid phase polymerization at 230 DEG C for 24 hours to obtain a polyamide resin.

Comparative Example  2: Preparation of polyamide resin

, 0.75 mol (74.76 g) of terephthalic acid, 0.30 mol (39.03 g) of itaconic acid, 0.79 mol (91.51 g) of 1,6-hexamethylenediamine, 0.075 mol ) And 139.87 mL of water were placed in a 1 liter autoclave and filled with nitrogen. After stirring at 100 ℃ 60 minutes and warmed for 2 hours at 250 ℃ while maintaining 25kgf / cm ² it was allowed to react for 3 hours at this temperature. The pressure was reduced to 15 kgf / cm < ² >, and the reaction was conducted for 1 hour to prepare a polyamide prepolymer. The prepared polyamide prepolymer was subjected to solid phase polymerization at 230 DEG C for 24 hours to obtain a polyamide resin.

Comparative Example  3: Preparation of polyamide resin

0.39 mol (80.99 g) of terephthalic acid, 0.26 mol (38.36 g) of adipic acid (AA), 0.76 mol (88.32 g) of 1,6-hexamethylenediamine, 0.023 mol (1.35 g) (0.21 g) and 139.44 mL of water were charged in a 1-liter autoclave and filled with nitrogen. After stirring at 100 ℃ 60 minutes and warmed for 2 hours at 250 ℃ while maintaining 25kgf / cm ² it was allowed to react for 3 hours at this temperature. The pressure was reduced to 15 kgf / cm < ² >, and the reaction was conducted for 1 hour to prepare a polyamide prepolymer. The prepared polyamide prepolymer was subjected to solid phase polymerization at 230 DEG C for 24 hours to obtain a polyamide resin.

Experimental Example

The following properties of the polyamide resins prepared in the above Examples and Comparative Examples were evaluated, and the results are shown in Table 1.

Property evaluation method

(1) Glass transition temperature, melting temperature and crystallization temperature (占 폚): Using a differential scanning calorimeter (DSC, Q20) manufactured by TA Instruments Inc. under a nitrogen atmosphere, a temperature range of 30 占 폚 to 350 占 폚, And a cooling rate of 10 DEG C / min. At this time, the crystallization temperature was determined as the maximum point of the exothermic peak during cooling, the melting temperature was determined as the maximum point of the endothermic peak at the second temperature rise, and the glass transition temperature was determined as the temperature measured at the second temperature rise.

(2) Intrinsic viscosity (dL / g): Measured using a 97% sulfuric acid solution and a Ubbelodhde viscometer at 25 ° C.

(3) Flowability (mm): Sumitomo injection machine SG75H-MIV was used. The cylinder temperature and the mold temperature were set at 320 DEG C and the injection pressure was set at 15 MPa to measure the flow distance.

(4) Water Absorption Rate (%): A specimen having a length of 100 mm, a width of 100 mm and a thickness of 3 mm was prepared and vacuum-dried at 120 ° C for 4 hours. The weight (W ₀ ) of the dried specimen is measured. The dried specimens are treated in a thermo-hygrostat at 50 ° C and 90% RH for 48 hours and the weight (W ₁ ) of the specimens is measured. The water absorption rate was calculated according to the following formula.

Water Absorption Rate (%) = | W ₁ -W ₀ | / W ₀ * 100

(5) Strength retention ratio (%): The strength retention ratio is a ratio of tensile strength after treatment to tensile strength before treatment for 24 hours at a temperature of 80 ° C and a relative humidity of 95% in a thermo-hygrostat. The tensile strength was measured according to ISO 527 (23 캜, 5 mm / min).

(6) Brightness: The L * value is measured using a colorimeter based on the criteria defined in ASTM D 1209.

Example Comparative Example One 2 3 4 One 2 3 Mole defense * 1.013 1.013 1.013 1.010 0.95 1.05 1.013 Glass transition temperature (캜) 125 119 112 127 117 109 100 Melting temperature (캜) 335 321 307 336 316 296 325 Crystallization temperature (캜) 289 288 262 288 279 255 292 Intrinsic viscosity (dL / g) 0.77 0.99 1.05 0.92 0.56 0.61 0.75 Flowability (mm) 131 124 120 126 149 138 115 Water Absorption Rate (%) 1.8 1.3 1.1 1.5 2.5 2.3 2.1 Strength retention (%) 93 94 93 94 87 89 91 Brightness 94 92 93 94 82 83 91

* Mortality Ratio: The ratio of moles of 1,6-hexamethylenediamine to the sum of moles of terephthalic acid and itaconic acid

As shown in Table 1, the polyamide resin according to the present invention has high heat resistance, excellent moldability in view of melting temperature, crystallization temperature and flow length, low water absorption rate, high strength retention, (See Examples 1-3). On the other hand, the polyamide resin whose molar ratio is out of the range of 0.98-1.02 had poor strength retention, heat resistance and gloss, and also had an influence on the increase of the molecular weight during solid phase polymerization and the water absorption rate was also poor (Comparative Example 1-2 Reference). In addition, the polyamide resin of the present invention replaces adipic acid and contains itaconic acid, thereby ensuring environment-friendly, similar or excellent physical properties (see Comparative Example 3).

Claims (13)

(C) relative to the total number of moles of (A) + (B) in the polymerization, the ratio of the number of moles of (C) to the total number of moles of (A) ) / ((A) + (B)) is 0.98-1.02. The polyamide resin according to claim 1, wherein the (B) itaconic acid is contained in an amount of 10 mol% or more of the total molar amount of (A) + (B) + (C). The polyamide resin according to claim 1, wherein the aromatic dicarboxylic acid monomer (A) is contained in an amount of 20 mol% or more of the total molar amount of (A) + (B) + (C). The method of claim 1, wherein the (A) aromatic dicarboxylic acid monomer is selected from the group consisting of terephthalic acid, isophthalic acid, 2,6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, Phenylene dioxydiacetic acid, diphenic acid, 4'4'-oxybis (benzoic acid), diphenylmethane-4,4'-dicarboxylic acid, diphenyl Sulfone-4,4'-dicarboxylic acid, 4-4'-diphenylcarboxylic acid, or a mixture thereof. The polyamide resin according to claim 1, wherein the aliphatic diamine monomer (C) is contained in an amount of 20 mol% or more in the total molar amount of (A) + (B) + (C). The polyimide resin composition according to claim 1, wherein the aliphatic diamine monomer (C) is at least one selected from the group consisting of 1,4-butanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, -Methyl-1,5-pentanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6- hexanediamine, , Ethyleneglycol bis (3-aminopropyl) ether (EGBA), 1,7-diamino-3,5-dioxoheptane or Wherein the polyamide resin is a mixture thereof. 2. The polyamide resin according to claim 1, wherein the polyamide resin is encapsulated with a terminal end-capping agent selected from an aliphatic carboxylic acid or an aromatic carboxylic acid. 8. The composition of claim 7, wherein the endblocking agent is selected from the group consisting of acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, Wherein the polyamide resin is at least one selected from the group consisting of an acid, benzoic acid, toluic acid,? -Naphthalenecarboxylic acid,? -Naphthalenecarboxylic acid and methylnaphthalenecarboxylic acid. The polyamide resin according to claim 1, wherein the polyamide resin has a glass transition temperature of 100 ° C to 130 ° C. The polyamide resin according to claim 1, wherein the polyamide resin has a water absorption rate of 2.0% or less after being treated at 50 ° C and 90% relative humidity for 48 hours. Comprising the step of copolymerizing a mixture of (A) an aromatic dicarboxylic acid monomer, (B) itaconic acid and (C) an aliphatic diamine monomer, wherein the number of moles of (C) relative to the total number of moles of (A) (C) / ((A) + (B)) of from 0.98 to 1.02. 12. The method for producing a polyamide resin according to claim 11, wherein the (B) itaconic acid is contained in an amount of 10 mol% or more of the total molar amount of (A) + (B) + (C). An article formed from the polyamide resin of any one of claims 1 to 10 or the polyamide resin produced by the method of claim 11 or 12.