JP2000256553A - Polyamide resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyamide resin composition excellent in various characteristics such as heat resistance, low water absorption properties, chemical resistance, hot water resistance, heat aging resistance, dynamic characteristics, flow properties and the like and provide molded products therefrom. SOLUTION: This polyamide resin composition consists of 50-99 pts.wt. of a polyamide resin (I) comprising a dicarboxylic acid unit (a) containing 60-100 mole % of terephthalic acid unit and a diamine unit containing 60-100 mole % of a 6-18C aliphatic alkylenediamine unit (b) and 50-1 pts.wt. of a polystyrene resin (II).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyamide resin composition comprising a semi-aromatic polyamide resin and a polystyrene resin, and to a molded article comprising the same. The polyamide resin composition of the present invention is excellent in various properties such as heat resistance, low water absorption, chemical resistance, hot water resistance, heat aging resistance, mechanical properties, and fluidity. Various fillers such as electric and electronic parts, automobile parts,
It can be used very effectively for industrial materials, industrial materials, household goods and a wide range of other uses.

[0002]

2. Description of the Related Art General-purpose polyamide resins represented by nylon 6, nylon 66, etc. are widely used as fibers for clothing, industrial materials, general-purpose engineering plastics, etc. due to their excellent properties and ease of melt molding. However, on the other hand, problems such as insufficient heat resistance and poor dimensional stability due to water absorption have been pointed out. Particularly in the electric and electronic fields where reflow soldering heat resistance is required with the recent development of surface mount technology (SMT), and in the engine room parts of automobiles where the demand for heat resistance is increasing year by year, the conventional general-purpose polyamide resin has the above-mentioned properties. And a polyamide resin having more excellent heat resistance, dimensional stability, mechanical properties and physicochemical properties has been demanded.

In order to improve the heat resistance and low water absorption of a polyamide resin, a resin composition comprising a polyamide resin and a styrene-based polymer having a syndiotactic structure and a specific compatibilizer has been proposed. (Japanese Patent Laid-Open No. 2-21)
No. 9843). However, Japanese Patent Laid-Open No. 2-21
No. 9843, the polyamide specifically described is an aliphatic polyamide alone. According to the study of the present inventors, when such an aliphatic polyamide is used, the obtained resin composition Properties such as chemical resistance, low water absorption, hot water resistance, heat resistance and heat aging resistance are inferior, and it cannot be said that they have practically sufficient performance.

Various semi-aromatic polyamide resins containing terephthalic acid and an aliphatic alkylenediamine having 6 to 18 carbon atoms as main components have been proposed, and some of them have been put to practical use. These semi-aromatic polyamide resins have various properties such as heat resistance, low water absorption, chemical resistance, etc. as compared with conventional general-purpose polyamide resins. At the time of molding a product, problems such as insufficient filling of the resin into the mold due to insufficient fluidity have been pointed out, and the actual situation is that further improvement in fluidity is required.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyamide resin composition having excellent properties such as heat resistance, low water absorption, chemical resistance, hot water resistance, heat aging resistance, mechanical properties and fluidity. An object of the present invention is to provide a molded product comprising the same.

[0006]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, a polyamide resin composition in which a polystyrene resin is blended with a semi-aromatic polyamide resin in a specific ratio has been found to be heat resistant. Properties, low water absorption, chemical resistance,
The inventors have found that they have excellent properties such as hot water resistance, heat aging resistance, mechanical properties, and fluidity, and have completed the present invention.

That is, the present invention relates to a dicarboxylic acid unit (a) containing 60 to 100 mol% of a terephthalic acid unit and an aliphatic alkylenediamine unit having 6 to 18 carbon atoms.
The present invention relates to a polyamide resin composition comprising 50 to 99 parts by weight of a polyamide resin (I) composed of a diamine unit (b) and 50 to 1 part by weight of a polystyrene resin (II). Further, the present invention relates to a molded article comprising the polyamide resin composition.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The dicarboxylic acid unit (a) constituting the polyamide resin (I) used in the present invention has a terephthalic acid unit of 6
0-100 mol% is contained. The content of the terephthalic acid unit is preferably in the range of 75 to 100 mol%, and more preferably in the range of 90 to 100 mol%. When the content of the terephthalic acid unit is less than 60 mol%, the heat resistance of the obtained polyamide resin composition decreases.

The above dicarboxylic acid unit (a) may contain a dicarboxylic acid unit other than the terephthalic acid unit as long as it is 40 mol% or less. As the other dicarboxylic acid unit, malonic acid, dimethylmalonic acid, succinic acid,
Aliphatic dicarboxylic acids such as glutaric acid, adipic acid, 2-methyladipic acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid, 3,3-diethylsuccinic acid, azelaic acid, sebacic acid and suberic acid; 1,3
Alicyclic dicarboxylic acids such as -cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid; isophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid;
1,4-phenylenedioxydiacetic acid, 1,3-phenylenedioxydiacetic acid, diphenic acid, dibenzoic acid, 4,4 ′
And units derived from aromatic dicarboxylic acids such as -oxydibenzoic acid, diphenylmethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, and 4,4'-biphenyldicarboxylic acid. , One or more of these can be used.
Of these, units derived from aromatic dicarboxylic acids are preferred. The content of these other dicarboxylic acid units is preferably 25 mol% or less, more preferably 10 mol% or less. Further, a unit derived from a polycarboxylic acid such as trimellitic acid, trimesic acid and pyromellitic acid may be contained within a range in which melt molding is possible.

The polyamide resin (I) used in the present invention
Contains 60 to 100 mol% of an aliphatic alkylenediamine unit having 6 to 18 carbon atoms. The content of the aliphatic alkylenediamine unit is preferably in the range of 75 to 100 mol%,
More preferably, it is in the range of 90 to 100 mol%.
When the content of the aliphatic alkylenediamine unit having 6 to 18 carbon atoms is less than 60 mol%, various properties such as heat resistance, low water absorption and chemical resistance of the obtained polyamide resin composition are reduced. Examples of the aliphatic alkylenediamine unit having 6 to 18 carbon atoms include 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, and 1,10-decanediamine Linear aliphatic alkylenediamines such as 1,1,11-undecanediamine and 1,12-dodecanediamine; 1
-Butyl-1,2-ethanediamine, 1,1-dimethyl-1,4-butanediamine, 1-ethyl-1,4-butanediamine, 1,2-dimethyl-1,4-butanediamine, 1,3 -Dimethyl-1,4-butanediamine, 1,
4-dimethyl-1,4-butanediamine, 2,3-dimethyl-1,4-butanediamine, 2-methyl-1,5-
Pentanediamine, 3-methyl-1,5-pentanediamine, 2,5-dimethyl-1,6-hexanediamine,
2,4-dimethyl-1,6-hexanediamine, 3,3
-Dimethyl-1,6-hexanediamine, 2,2-dimethyl-1,6-hexanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6- Hexanediamine, 2,4-diethyl-
1,6-hexanediamine, 2,2-dimethyl-1,7
-Heptanediamine, 2,3-dimethyl-1,7-heptanediamine, 2,4-dimethyl-1,7-heptanediamine, 2,5-dimethyl-1,7-heptanediamine, 2-methyl-1,8 -Octanediamine, 3-methyl-1,8-octanediamine, 4-methyl-1,8-
Octanediamine, 1,3-dimethyl-1,8-octanediamine, 1,4-dimethyl-1,8-octanediamine, 2,4-dimethyl-1,8-octanediamine,
3,4-dimethyl-1,8-octanediamine, 4,5
-Dimethyl-1,8-octanediamine, 2,2-dimethyl-1,8-octanediamine, 3,3-dimethyl-
1,8-octanediamine, 4,4-dimethyl-1,8
Examples thereof include units derived from branched aliphatic alkylenediamines such as -octanediamine and 5-methyl-1,9-nonanediamine, and one or more of these units can be used.

Among the above aliphatic alkylenediamine units, 1,6-hexanediamine, 1,8-octanediamine, 2-methyl-1,8-octanediamine,
9-nonanediamine, 1,10-decanediamine, 1,
Units derived from 11-undecanediamine and 1,12-dodecanediamine are preferred, and from the viewpoint of obtaining a polyamide resin composition excellent in heat resistance, moldability, low water absorption, and light weight, 1,9-nonanediamine unit and And / or 2-methyl-1,8-octanediamine units are more preferred. When 1,9-nonanediamine unit and 2-methyl-1,8-octanediamine unit are used in combination, 1,9-nonanediamine unit: 2-methyl-1,
The molar ratio of 8-octanediamine units is 99: 1 to 2
It is preferably in the range of 0:80, 99: 1 to 6
More preferably, it is in the range of 0:40, and 99: 1 to 99: 1.
More preferably, it is within the range of 80:20.

The above diamine unit (b) is 40 mol%
In the following, other diamine units other than the aliphatic alkylenediamine unit having 6 to 18 carbon atoms may be contained.
Examples of the other diamine unit include aliphatic diamines such as ethylenediamine, propylenediamine, and 1,4-butanediamine; alicyclic rings such as cyclohexanediamine, methylcyclohexanediamine, isophoronediamine, norbornanedimethylamine, and tricyclodecanedimethylamine. Formula diamine: p-phenylenediamine, m-phenylenediamine, p-xylylenediamine, m-xylylenediamine, 4,4′-diaminodiphenylmethane,
Examples include units derived from aromatic diamines such as 4,4'-diaminodiphenyl sulfone and 4,4'-diaminodiphenyl ether, and one or more of these units can be used. The content of these other diamine units is preferably 25 mol% or less, more preferably 10 mol% or less.

The polyamide resin (I) used in the present invention
It is preferable that 10% or more of the terminal groups of the molecular chain are blocked with a terminal blocking agent. The ratio of the terminal groups being blocked (terminal blocking ratio) is more preferably 40% or more, and even more preferably 70% or more. When a polyamide resin having an end capping rate of 10% or more is used, a polyamide resin composition excellent in melt stability, hot water resistance and the like can be obtained.

The terminal capping ratio of the polyamide resin (I) is determined by measuring the number of carboxyl group terminals, amino group terminals and the number of terminals capped with the terminal capping agent in the polyamide resin. ). The number of each terminal group is determined by ¹ H-NMR from the integrated value of the characteristic signal corresponding to each terminal group.
It is preferable in terms of simplicity.

End-capping rate (%) = [(AB) / A] × 100 (1) wherein A is the total number of molecular chain terminal groups (this is usually equal to twice the number of polyamide molecules) ), And B represents the total number of carboxyl group terminals and amino group terminals. ]

The terminal capping agent is not particularly limited as long as it is a monofunctional compound having reactivity with an amino group or a carboxyl group at the terminal of the polyamide resin. From, monocarboxylic acid or monoamine is preferable, from the viewpoint of easy handling,
Monocarboxylic acids are more preferred. In addition, acid anhydrides such as phthalic anhydride, monoisocyanates, monoacid halides, monoesters, and monoalcohols can also be used.

The monocarboxylic acid used as the terminal blocking agent is not particularly limited as long as it has reactivity with an amino group. For example, acetic acid, propionic acid, butyric acid,
Valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid,
Aliphatic monocarboxylic acids such as pivalic acid and isobutyric acid; alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid; benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, phenylacetic acid And aromatic monocarboxylic acids; and arbitrary mixtures thereof. Of these,
Acetic acid, from the viewpoint of reactivity,
Preferred are propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, and benzoic acid.

The monoamine used as the terminal blocking agent is not particularly limited as long as it has reactivity with a carboxyl group. Examples thereof include methylamine, ethylamine, propylamine, butylamine, hexylamine,
Aliphatic monoamines such as octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine and dibutylamine; alicyclic monoamines such as cyclohexylamine and dicyclohexylamine;
Aromatic monoamines such as aniline, toluidine, diphenylamine, and naphthylamine; arbitrary mixtures thereof; Among them, butylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine, and aniline are preferred from the viewpoints of reactivity, high boiling point, stability of a sealed end, and price.

The polyamide resin (I) can be produced by using any known method for producing a crystalline polyamide. For example, a polymerization method such as a solution polymerization method or an interfacial polymerization method using an acid chloride and a diamine as raw materials, a melt polymerization method using a dicarboxylic acid and a diamine as raw materials, a solid phase polymerization method, and a melt extruder polymerization method can be employed. .

The polyamide resin (I) is prepared by adding, for example, a diamine, a dicarboxylic acid, a catalyst and, if necessary, an end-capping agent at a time to produce a nylon salt.
Heat polymerization at a temperature of 250 ° C. to obtain intrinsic viscosity [η]
It can be produced by preparing a prepolymer of 0.1 to 0.6 dl / g and subjecting it to solid phase polymerization or polymerization using a melt extruder. When the intrinsic viscosity [η] of the prepolymer is in the range of 0.1 to 0.6 dl / g, deviation of the molar balance between carboxyl groups and amino groups and lowering of the polymerization rate in the subsequent polymerization stage are small, and A polyamide resin having a small molecular weight distribution and excellent in various physical properties and moldability can be obtained. When the final stage of the polymerization is carried out by solid phase polymerization, it is preferable to carry out the reaction under reduced pressure or under an inert gas flow. The polymerization temperature at this time is 200 to 280
The temperature is preferably in the range of ° C. When the polymerization is carried out under such conditions, the polymerization rate is high, the productivity is excellent, and coloring and gelation can be effectively suppressed. The polymerization temperature in the case where the final stage of the polymerization is carried out by a melt extruder is preferably 370 ° C. or lower. When the polymerization is carried out under such conditions, a polyamide resin with almost no decomposition or deterioration of the polyamide resin is obtained.

When producing the polyamide resin (I), for example, phosphoric acid, phosphorous acid, hypophosphorous acid, salts or esters thereof, etc. are added in addition to the above terminal blocking agent. Can be. As the above salts or esters, phosphoric acid, phosphorous acid or hypophosphorous acid and potassium, sodium, magnesium, vanadium, calcium, zinc, cobalt, manganese, tin, tungsten,
Salts with metals such as germanium, titanium and antimony; ammonium salts of phosphoric acid, phosphorous acid or hypophosphorous acid; ethyl ester, isopropyl ester, butyl ester, hexyl ester of phosphoric acid, phosphorous acid or hypophosphorous acid , Isodecyl ester, octadecyl ester, decyl ester, stearyl ester, phenyl ester and the like.

The intrinsic viscosity [η] of the polyamide resin (I) is preferably in the range of 0.6 to 2.0 dl / g, and more preferably in the range of 0.7 to 1.9 dl / g. Is more preferable, and it is still more preferable that it is in the range of 0.8 to 1.8 dl / g. When the intrinsic viscosity is less than 0.6 dl / g, the mechanical properties of the obtained polyamide resin composition tend to be impaired, and when the intrinsic viscosity is more than 2.0 dl / g, the fluidity of the obtained polyamide resin composition The moldability tends to decrease and the moldability tends to deteriorate. The above intrinsic viscosity is a value measured in concentrated sulfuric acid at 30 ° C.

The polystyrene resin (I) used in the present invention
Examples of I) include polystyrene; polyalkylstyrene such as poly-p-methylstyrene, poly-m-methylstyrene, poly-o-methylstyrene, polyethylstyrene, polyisopropylstyrene and polyt-butylstyrene; Examples thereof include polyalkoxystyrenes such as methoxystyrene and polyethoxystyrene, and one or more of these can be used. Further, monomers constituting these polystyrene resins, that is, styrene; p-methylstyrene, m-methylstyrene, o-methylstyrene, ethylstyrene, isopropylstyrene, t-butylstyrene and other alkylstyrenes; methoxystyrene, ethoxy Copolymers obtained by copolymerizing two or more of alkoxystyrenes such as styrene, and copolymers containing the above monomers as a main component can also be used. Among these, polystyrene;
Poly-p-methylstyrene; poly-m-methylstyrene; poly-o-methylstyrene; polyt-butylstyrene; a copolymer of styrene and p-methylstyrene is preferred, and polystyrene is more preferred.

The molecular weight of the polystyrene resin (II) is not particularly limited, and usually has a weight average molecular weight of 10,000.
0 to 1,000,000 are used, and 50,000
It is preferred to use those of ~ 800,000.

It is preferable to use a polystyrene resin having a syndiotactic structure as the polystyrene resin (II) because the mechanical properties are improved. Here, the syndiotactic structure refers to a three-dimensional structure in which phenyl groups and substituted phenyl groups, which are side chains, are alternately located in the opposite direction to the main chain of polystyrene resin (II) formed from carbon-carbon bonds. Meaning, the ratio of such a steric structure can be determined by a nuclear magnetic resonance method ( ¹³ C-NMR method) using isotope carbon. The ratio of the syndiotactic structure measured by this method is expressed in tacticity, for example, dyad (two consecutive structural units have a syndiotactic structure), triad (three consecutive structural units). This is indicated by the proportion of pentads (units having a syndiotactic structure) and pentads (consecutive five structural units have a syndiotactic structure). As the polystyrene resin having a syndiotactic structure used in the present invention, it is preferable to use a polystyrene resin having a syndiotacticity of dyad of 75% or more, and more preferably 85% or more of dyad. When the syndiotactic structure is expressed by a pentad, the pentad is 30%
It is preferable to use a polystyrene resin having the above syndiotacticity, and it is more preferable that the pentad is 50% or more.

The above polystyrene resin having a syndiotactic structure, for example, uses a titanium compound as a main catalyst and promotes a condensation product of water and a trialkylaluminum compound in an inert hydrocarbon solvent or in the absence of a solvent. It can be produced by polymerizing a styrene monomer using a catalyst system as a catalyst.

The weight ratio of the polyamide resin (I) to the polystyrene resin (II) in the polyamide resin composition of the present invention is in the range of 99: 1 to 50:50, and 97: 3 to 50:50.
It is preferably in the range of 60:40, 95: 5-6
More preferably, it is within the range of 5:35. When the content of the polystyrene resin (II) is less than 1% by weight based on the total weight of the polyamide resin (I) and the polystyrene resin (II), the fluidity of the obtained polyamide resin composition is not improved, Polystyrene resin (II) content is 50% by weight
When the ratio exceeds the above range, the heat resistance of the obtained polyamide resin composition is reduced.

The polyamide resin composition of the present invention may contain, if necessary, a fibrous filler such as glass fiber, carbon fiber, boron fiber, aramid fiber, and liquid crystal polyester fiber; silica, silica alumina, alumina, talc, graphite. And powdered fillers such as titanium dioxide, molybdenum disulfide, and polytetrafluoroethylene. These fillers are used in an amount of 1 part by weight based on 100 parts by weight of the total of the polyamide resin (I) and the polystyrene resin (II).
When blended at a ratio of about 150 parts by weight, a polyamide resin composition having a better balance between mechanical properties and moldability can be obtained.

Further, in addition to the above-mentioned filler, the polyamide resin composition of the present invention may further comprise, if necessary, a conventionally known copper-based stabilizer, a hindered phenol-based antioxidant, or a hindered amine-based antioxidant. , A phosphorus-based antioxidant, a thio-based antioxidant, a colorant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a plasticizer, a lubricant, a crystal nucleating agent, and other kinds of polymers. Further, the polyamide resin composition of the present invention may contain a conventionally known flame retardant or flame retardant auxiliary, if necessary.

The method for producing the polyamide resin composition of the present invention is not particularly limited, and any method may be used as long as it can uniformly mix the polyamide resin (I) and the polystyrene resin (II). It can be manufactured by melt-kneading with other components to be blended accordingly. Melt kneading can be performed using a kneader such as a single-screw extruder, a twin-screw extruder, a kneader, and a Banbury mixer, and the type of equipment and melt-kneading conditions used at that time are not particularly limited, By kneading at a temperature in the range of about 300 to 350 ° C. for 1 to 30 minutes, the polyamide resin composition of the present invention can be produced.

The polyamide resin composition of the present invention is generally subjected to heat molding such as injection molding, extrusion molding, press molding, blow molding, calender molding, cast molding, etc., depending on the type, application, shape, etc. of the intended molded article. A molded article can be manufactured by molding by the molding method used for the plastic resin composition. Further, a molding method obtained by combining the above-described molding methods can be employed. Further, the polyamide resin composition of the present invention and another polymer can be formed into a composite. By the above-mentioned molding, electric / electronic parts, automobile parts, industrial materials, industrial materials, machine parts, office equipment parts, household goods, sheets, films, textiles, and various other molded articles of any use and shape are manufactured. be able to.

[0032]

The present invention will be described below in more detail with reference to examples, but the present invention is not limited thereto. In the following Examples and Comparative Examples, measurement or evaluation of preparation of test pieces, fluidity, tensile yield strength, heat resistance, equilibrium water absorption, hot water resistance, chemical resistance and heat aging resistance were performed by the following methods. .

Preparation of test piece: Using an 80-ton injection molding machine manufactured by Nissei Plastic Industry Co., Ltd., cylinder temperature 320
° C (Examples 1 to 23) or 290 ° C (Comparative Examples 1 to 3)
4) For evaluation of tensile yield strength, hot water resistance, chemical resistance and heat aging resistance under conditions of a mold temperature of 150 ° C. (Examples 1 to 23) or a temperature of 80 ° C. (Comparative Examples 1 to 4). JIS1
No. dumbbell-type test piece; test piece for heat resistance evaluation (128 m
mx 12.7 mm x 6.2 mm).
Further, using a compression molding machine manufactured by Shinto Metal Industry Co., Ltd., at a temperature of 320 ° C. and a pressing pressure of 100 kg / cm ² , a press sheet (50 mm ×
(50 mm × 0.2 mm).

Flowability (bar flow flow length): Using the polyamide resin composition pellets obtained in Examples or Comparative Examples, the cylinder temperature was measured using an 80-ton injection molding machine manufactured by Nissei Plastics Industry Co., Ltd. 320 ° C. (Examples 15 to 2)
3) or 290 ° C. (Comparative Examples 1-4), mold temperature 1
500, 750 or 1000 kg under the condition of 50 ° C. (Examples 15 to 23) or 80 ° C. (Comparative Examples 1 to 4)
40 mm (horizontal) x 200 mm at an injection pressure of / cm ²
Injection molding was performed in a mold having a size of (length) × 0.5 mm (width), and the flow length was measured.

Tensile yield strength: The tensile yield strength was measured by using an autograph (manufactured by Shimadzu Corporation) according to JIS K7113, using the test piece prepared by the above method.

Heat resistance: Using a test piece prepared by the above method, using a weighted strain temperature measuring device (manufactured by Toyo Seiki Seisaku-sho, Ltd.) in accordance with JIS K7207.
The deflection temperature under load (DTUL) was measured under a load of 6 kgf and used as an index of heat resistance.

Equilibrium water absorption: A test piece prepared by the above method was dried under reduced pressure for 5 days, weighed, immersed in water at 23 ° C. for 10 days, weighed, and weighed for the increased weight before immersion. The equilibrium water absorption was determined from the ratio to

Hot water resistance: A test piece prepared by the above method was placed in a small pressure vessel (manufactured by Tabai Espec Corp.) in 12
After performing a steam treatment at 0 ° C. and 2 atm for 120 hours, the resultant was vacuum-dried at 120 ° C. for 120 hours. Using the test piece after the treatment, the tensile yield strength was measured using an autograph (manufactured by Shimadzu Corporation), and the retention of the test piece before the treatment with respect to the tensile yield strength was determined.

Chemical resistance: After immersing the test piece prepared by the above method in methyl alcohol at 23 ° C. for 7 days, the tensile yield strength was measured using an autograph (manufactured by Shimadzu Corporation). The retention of the test piece before immersion with respect to the tensile yield strength was determined.

Heat aging resistance: A test piece prepared by the above method was placed in a gear oven (manufactured by Tabai Espec Corp.) set at 150 ° C., subjected to a dry heat treatment for a certain period of time, and then autographed (manufactured by Shimadzu Corporation). ) Was used to measure the tensile yield strength, and the dry heat treatment time at which the retention of the test piece before treatment to the tensile yield strength was 50% was determined.

In the following Examples and Comparative Examples, the following polyamide resins and polystyrene resins were used.

Polyamide resin I PA9T: composed of terephthalic acid units and 1,9-nonanediamine units, having a melting point of 317 ° C., an intrinsic viscosity [η] (measured in concentrated sulfuric acid at 30 ° C.) of 1.0 dl / g, and a terminal A polyamide resin having a sealing rate (terminal blocking agent: benzoic acid) of 90%.

PA9MT: Terephthalic acid unit and 1,9
-Nonanediamine unit and 2-methyl-1,8-octanediamine unit (1,9-nonanediamine unit: 2-
When the molar ratio of methyl-1,8-octanediamine unit is 9
0:10), having a melting point of 308 ° C., an intrinsic viscosity [η] (measured in concentrated sulfuric acid at 30 ° C.) of 1.0 dl / g,
A polyamide resin having a terminal blocking ratio (terminal blocking agent: benzoic acid) of 90%.

PA6IT: composed of terephthalic acid units and isophthalic acid units (the molar ratio of terephthalic acid units: isophthalic acid units is 70:30) and 1,6-hexanediamine units, having a melting point of 310 ° C. and an intrinsic viscosity [η] A polyamide resin having a concentration of 1.0 dl / g (measured in concentrated sulfuric acid at 30 ° C.) and a terminal blocking ratio (terminal blocking agent: benzoic acid) of 90%.

Polystyrene resin II-1 "Stylon 685" manufactured by Asahi Kasei Corporation. Polystyrene resin II-2 Syndiotactic polystyrene “ZALEC S100” (polystyrene resin having a syndiotactic structure) manufactured by Idemitsu Petrochemical Co., Ltd.

Polyamide resin III PA66: UBE nylon 20 manufactured by Ube Industries, Ltd.
20B ".

Examples 1 to 14 A polyamide resin and a polystyrene resin shown in Table 1 or Table 2 below were premixed at a ratio shown in Table 1 or Table 2 and then a twin screw extruder (Nippon Steel Works, Ltd.) Made "T
EX44C "), melt-kneaded under the condition of a cylinder temperature of 320 ° C, extruded, cooled and cut to produce a pellet-shaped polyamide resin composition. Using the obtained polyamide resin composition, a test piece was prepared by the method described above, and the tensile yield strength, heat resistance, equilibrium water absorption, hot water resistance, chemical resistance, and heat aging resistance were evaluated by the above method. The results are shown in Tables 1 and 2 below.

Examples 15 to 17 The polyamide resin and the polystyrene resin shown in Table 3 below were premixed in the proportions shown in Table 3 and then mixed in a twin-screw extruder (“TEX44C” manufactured by Nippon Steel Corporation). The mixture was supplied, melt-kneaded under the condition of a cylinder temperature of 320 ° C., extruded, cooled and cut to produce a pellet-shaped polyamide resin composition. Using the obtained polyamide resin composition, the results of evaluating the fluidity by the method described above are shown in Table 3 below.
Shown in

Examples 18 to 23 Polyamide resins and polystyrene resins shown in Table 3 below were mixed with glass fibers (“CS3J-2” manufactured by Nitto Boseki Co., Ltd.).
56S "), polybrominated styrene (manufactured by Great Lakes Chemical" GLC PDBS-80 ") and sodium antimonate (Na ₂ O · manufactured by Nissan Chemical Industries, Ltd.
Sb ₂ O ₅ "San Epoch NA-1070L") and premixed at the ratios shown in Table 3 below, and then fed to a twin screw extruder ("TEX44C" manufactured by Nippon Steel Works, Ltd.) and a cylinder temperature of 320C The mixture was melt-kneaded, extruded, cooled and cut to produce a pellet-shaped polyamide resin composition. Using the obtained polyamide resin composition, the results of evaluating the fluidity by the method described above are shown in Table 3 below.
Shown in

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

[Table 3]

Comparative Examples 1 to 4 Polyamide resins and polystyrene resins shown in Table 4 below were premixed in the proportions shown in Table 4 below, and then mixed in a twin-screw extruder (“TEX44C” manufactured by Nippon Steel Works Ltd.). The mixture was supplied, melted and kneaded under the condition of a cylinder temperature of 290 ° C., extruded, cooled and cut to produce a pellet-shaped polyamide resin composition. Using the obtained polyamide resin composition, a test piece was prepared by the method described above, and the fluidity, tensile yield strength, heat resistance, equilibrium water absorption, hot water resistance, chemical resistance, and heat aging resistance were determined as described above. Table 4 shows the results evaluated in
Shown in

[0054]

[Table 4]

[0055]

According to the present invention, a polyamide resin composition having excellent properties such as heat resistance, low water absorption, chemical resistance, hot water resistance, heat aging resistance, mechanical properties, fluidity, and the like, and a molded article comprising the same are provided. Is provided.

Claims (5)

[Claims] 1. A terephthalic acid unit having a content of 60 to 100 mol%
50 to 99 parts by weight of a polyamide resin (I) comprising a dicarboxylic acid unit (a) to be contained and a diamine unit (b) containing 60 to 100 mol% of an aliphatic alkylenediamine unit having 6 to 18 carbon atoms, and a polystyrene resin ( II)
A polyamide resin composition comprising 50 to 1 part by weight. 2. The polyamide resin composition according to claim 1, wherein the aliphatic alkylenediamine unit having 6 to 18 carbon atoms is a 1,9-nonanediamine unit and / or a 2-methyl-1,8-octanediamine unit. . 3. The polystyrene resin (II) is a polystyrene resin having a syndiotactic structure.
Or the polyamide resin composition according to 2. 4. The polyamide resin (I) has an intrinsic viscosity of 0.1.
The polyamide resin composition according to any one of claims 1 to 3, wherein the amount is 6 to 2.0 dl / g. 5. A molded article comprising the polyamide resin composition according to claim 1.