JP2022030403A - Polyamide resin composition and its compact - Google Patents

Abstract

To provide a polyamide resin composition capable of manufacturing a compact excellent in mechanical strength and hydrolysis resistance and its compact.SOLUTION: A polyamide resin composition containing 10 to 200 pts. mass of an inorganic filler (B) with respect to 100 pts.mass of a semi aromatic polyamide (A), in which when an amount of terminal amino groups of a molecular chain of the semi-aromatic polyamide (A) is set to [NH2] (μ equivalent/g) and an amount of terminal carboxy groups is set to [COOH] (μ equivalent/g], the following formulas (I) and (II) are satisfied, a number average molecular weight of the semi aromatic polyamide (a) in an ISO multipurpose test piece A type dumbbell obtained by injection molding the polyamide resin composition under the condition of a cylinder temperature of 320°C and a mold temperature of 140°C is 5500 or larger. 1≤[NH2]/[COOH]<6 (I).SELECTED DRAWING: None

Description

The present invention relates to a polyamide resin composition and a molded product thereof. More specifically, the present invention relates to a polyamide resin composition capable of producing a molded product having excellent mechanical strength and hydrolysis resistance, and the molded product thereof.

Polyamide resins are excellent in strength, heat resistance, chemical resistance, etc., and have been conventionally used for mechanical parts of automobiles. For example, a molded product of a polyamide resin composition is also used for a tube for circulating a long-life coolant (hereinafter, may be referred to as “LLC”) aqueous solution used for cooling an automobile engine or a refrigerant for cooling an air conditioner. Has been done. In particular, in recent years, mechanical parts for automobiles have been studied more actively, and a polyamide resin composition capable of producing mechanical parts having superior strength, heat resistance, chemical resistance, etc., as compared with conventional polyamide resin compositions is desired. There is.

As a polyamide resin composition that meets the demands for mechanical parts of automobiles, for example, Patent Document 1 states that a predetermined proportion or more of terminal groups of a molecular chain of a specific semi-aromatic polyamide resin is terminally sealed and the amount of residual amino groups remains. Disclosed is a polyamide resin composition containing a semi-aromatic polyamide having a value obtained by dividing the amount of terminal amino groups by the amount of terminal carboxy groups to a predetermined value or more.

In Patent Document 2, a polyamide resin composition exhibiting excellent hydrolysis resistance, which comprises a copolyamide having a melting point of about 240 ° C. or lower, an amine terminal of at least about 30 μeq / g, and an intrinsic viscosity of at least about 1.2. The thing is disclosed.

Patent Document 3 includes a polyamide resin having a melting point of 260 ° C., containing a semi-aromatic repeating unit and an aliphatic repeating unit, and having an acid terminal of at least about 50 meq / Kg, a reinforcing material, and a reinforcing agent. , A polyamide composition having a high acid terminal suitable for producing a molded product exhibiting good hydrolysis resistance is disclosed.

In Patent Document 4, a predetermined amount of the polyamide resin and the (B) strengthening agent is contained, and the difference between the carboxy group terminal concentration [COOH] and the amino group terminal concentration [NH ₂ ] in the polyamide resin is set as a predetermined range, and the viscosity number [ VN] is disclosed as a reinforced high molecular weight polyamide resin composition having improved hydrolysis resistance having a predetermined value or more.

Japanese Unexamined Patent Publication No. 2013-40346 International Publication No. 2007/044573 International Publication 2011/084797 JP-A-2015-199873

When a molded product of a polyamide resin composition is used as a mechanical component of an automobile in contact with an LLC aqueous solution used for cooling an engine, the molded product is exposed to an acid generated by the high temperature of the LLC aqueous solution for a long time. To. The molded product is also exposed to the terminal carboxy group in the polyamide resin and the acid derived from the carboxy group generated by the hydrolysis of the polyamide resin. When a molded product of a conventional polyamide resin composition as disclosed in Patent Document 1 or the like is brought into contact with an LLC aqueous solution, hydrolysis easily occurs and the molecular weight is reduced, and as a result, the mechanical strength of the molded product is reduced. There was a problem that it decreased.

On the other hand, although Patent Document 2 mentions the hydrolysis resistance of the polyamide resin in the presence of water, the resistance of the polyamide resin when contacted with an LLC aqueous solution, which is a harsher environment such as a higher temperature than water. No mention is made of hydrolyzability.

Further, in Patent Document 3, although there is a reference to the hydrolysis resistance of the polyamide resin in the presence of water, no mention is made of the hydrolysis resistance of the polyamide resin when it is brought into contact with an LLC aqueous solution which is a harsher environment. Not.

Further, in Cited Document 4, the hydrolysis resistance of the molded product of the polyamide resin composition when contacted with the LLC aqueous solution is evaluated, but the mechanical strength after contact with the LLC aqueous solution is significantly reduced, and the LLC aqueous solution is significantly reduced. It cannot be said that it has sufficient hydrolysis resistance.

In view of the above circumstances, it is an object of the present invention to provide a polyamide resin composition capable of producing a molded product having excellent hydrolysis resistance and mechanical strength, and a molded product thereof.

As a result of diligent studies by the present inventor, a polyamide resin composition containing a predetermined semi-aromatic polyamide and an inorganic filler in a predetermined amount, which is contained in an ISO multipurpose test piece A type dumbbell injection-molded under predetermined conditions. It was found that a molded product having excellent hydrolysis resistance and mechanical strength can be obtained by molding using a polyamide resin composition having a semi-aromatic polyamide having a number average molecular weight of 5500 or more, and further based on the findings. The present invention was completed after repeated studies.

That is, the present invention provides the following [1] to [12].
[1] A polyamide resin composition containing 10 to 200 parts by mass of an inorganic filler (B) with respect to 100 parts by mass of a semi-aromatic polyamide (A).
When the amount of terminal amino groups in the molecular chain of the semi-aromatic polyamide (A) is expressed as [NH ₂ ] (μ equivalent / g) and the amount of terminal carboxy groups is expressed as [COOH] (μ equivalent / g). Satisfy the following formula (I) and
A polyamide resin having a number average molecular weight of 5500 or more of the semi-aromatic polyamide (a) in an ISO multipurpose test piece A type dumbbell obtained by injection molding the polyamide resin composition under the conditions of a cylinder temperature of 320 ° C. and a mold temperature of 140 ° C. Composition.
1 ≦ [NH ₂ ] / [COOH] <6 (I)
[2] The polyamide resin composition according to the above [1], which contains 0.01 to 5 parts by mass of the organic antioxidant (C) with respect to 100 parts by mass of the semi-aromatic polyamide (A).
[3] The polyamide resin composition according to the above [1] or [2], wherein the content of the copper compound is less than 1 part by mass with respect to 100 parts by mass of the semi-aromatic polyamide (A).
[4] The polyamide resin composition according to any one of [1] to [3] above, wherein the content of the copper compound is less than 0.01 parts by mass with respect to 100 parts by mass of the semi-aromatic polyamide (A). thing.
[5] The semi-aromatic polyamide (A) contains a dicarboxylic acid unit and a diamine unit.
50 to 100 mol% of the dicarboxylic acid unit is a structural unit derived from at least one selected from terephthalic acid or naphthalenedicarboxylic acid, and 60 to 100 mol% of the diamine unit is an aliphatic diamine having 6 to 10 carbon atoms. The polyamide resin composition according to any one of the above [1] to [4], which is a structural unit derived from.
[6] The polyamide resin according to the above [5], wherein the aliphatic diamine is at least one selected from 1,10-decanediamine, 1,9-nonanediamine and 2-methyl-1,8-octanediamine. Composition.
[7] The polyamide resin composition according to the above [5] or [6], wherein the aliphatic diamine is 1,9-nonanediamine and 2-methyl-1,8-octanediamine.
[8] The polyamide resin composition according to the above [7], wherein the molar ratio of 1,9-nonamethylenediamine to 2-methyl-1,8-octamethylenediamine is 99: 1 to 40:60.
[9] The polyamide resin composition according to any one of the above [1] to [8], wherein the inorganic filler (B) is at least one selected from glass fibers and carbon fibers.
[10] The molded body of the polyamide resin composition according to any one of the above [1] to [9].
[11] The molded product of the polyamide resin composition according to the above [10], which is a component that comes into contact with the long life coolant.

According to the present invention, it is possible to provide a polyamide resin composition capable of producing a molded product having excellent hydrolysis resistance and mechanical strength, and a molded product thereof.

Hereinafter, description will be made based on an example of an embodiment of the present invention (hereinafter, may be referred to as “the present embodiment”). However, the embodiments shown below are examples for embodying the technical idea of the present invention, and the present invention is not limited to the following description.
Further, although the preferred embodiment of the embodiment is shown in the present specification, a combination of two or more individual preferred embodiments is also a preferred embodiment. When there are several numerical ranges for the items shown in the numerical range, the lower limit value and the upper limit value thereof can be selectively combined to form a preferable form.
In this specification, when the numerical range of "XX to YY" is described, it means "XX or more and YY or less".

[Polyamide resin composition]
The polyamide resin composition of the present invention contains 10 to 200 parts by mass of the inorganic filler (B) with respect to 100 parts by mass of the semi-aromatic polyamide (A), and the terminal of the molecular chain of the semi-aromatic polyamide (A). When the amino group amount is expressed as [NH ₂ ] (μ equivalent / g) and the terminal carboxy group amount is expressed as [COOH] (μ equivalent / g), the following formula (I) is satisfied, and the polyamide resin composition is satisfied. The semi-aromatic polyamide (a) in the ISO multipurpose test piece A type dumbbell injection-molded under the conditions of a cylinder temperature of 320 ° C. and a mold temperature of 140 ° C. is characterized by having a number average molecular weight of 5500 or more.
1 ≦ [NH ₂ ] / [COOH] <6 (I)
By using such a polyamide resin composition of the present invention, it is possible to produce a molded product having excellent hydrolysis resistance and mechanical strength. The reason is not always clear, but as in the above formula (I), the value obtained by dividing the amount of the terminal amino group by the amount of the terminal carboxy group is set as a predetermined value.
It is considered that hydrolysis caused by the terminal carboxy group of the semi-aromatic polyamide can be suppressed, and the mechanical strength is improved by containing a predetermined amount of the inorganic filler (B) in the polyamide resin composition. ..

In the present invention, the injection molding conditions for obtaining the ISO multipurpose test piece A type dumbbell using the polyamide resin composition are a cylinder temperature of 320 ° C. and a mold temperature of 140 ° C., and a cycle time of preferably 15 to 60 seconds. It is more preferably 20 to 50 seconds, still more preferably 25 to 40 seconds.

The number average molecular weight of the semi-aromatic polyamide (a) in the ISO multipurpose test piece A type dumbbell obtained by injection molding the polyamide resin composition of the present invention under the above conditions is excellent in hydrolysis resistance, mechanical strength and fatigue resistance. From the viewpoint of obtaining a molded product, it is 5500 or more, preferably 5800 or more, more preferably 6000 or more, still more preferably 6200 or more, still more preferably 6400 or more, still more preferably 7000 or more, and the polyamide resin composition. From the viewpoint of fluidity and moldability, it is preferably 9500 or less, more preferably 9000 or less, still more preferably 8700 or less, still more preferably 8500 or less.
In the present invention, the number average molecular weight of the semi-aromatic polyamide (a) in the ISO multipurpose test piece A type dumbbell is the number average molecular weight in terms of polymethylmethacrylate obtained from the measurement of gel permeation chromatography (GPC). .. More specifically, the number average molecular weight is a value obtained by the measuring method described in Examples.
The semi-aromatic polyamide (a) is an injection molding of a polyamide resin composition containing 10 to 200 parts by mass of an inorganic filler (B) with respect to 100 parts by mass of the semi-aromatic polyamide (A). It is a semi-aromatic polyamide contained in the ISO multipurpose test piece A type dumbbell.

The weight average molecular weight of the semi-aromatic polyamide (a) in the ISO multipurpose test piece A type dumbbell obtained by injection molding the polyamide resin composition of the present invention under the above conditions is excellent in hydrolysis resistance, mechanical strength and fatigue resistance. From the viewpoint of obtaining a molded product, it is preferably 14,000 or more, more preferably 16,000 or more, further preferably 18,000 or more, still more preferably 20,000 or more, and preferably 100,000 from the viewpoint of fluidity and moldability of the polyamide resin composition. Below, it is more preferably 70,000 or less, further preferably 50,000 or less, and even more preferably 40,000 or less.
In the present invention, the weight average molecular weight of the semi-aromatic polyamide (a) in the ISO multipurpose test piece A type dumbbell is the weight average molecular weight in terms of polymethylmethacrylate obtained from the measurement of gel permeation chromatography (GPC). ..

The viscosity number of the semi-aromatic polyamide (a) in the ISO multipurpose test piece A type dumbbell obtained by injection molding the polyamide resin composition of the present invention under the above conditions is less than 160 mL / g. The viscosity number is preferably 90 mL / g or more, more preferably 100 mL / g or more, still more preferably 110 mL / g or more, from the viewpoint of obtaining a molded product having excellent hydrolysis resistance, mechanical strength and fatigue resistance. From the viewpoint of fluidity and moldability of the polyamide resin composition, it is preferably 155 mL / g or less, more preferably 150 mL / g or less, still more preferably 140 mL / g or less.
In the present invention, the viscosity number of the semi-aromatic polyamide (a) in the ISO multipurpose test piece A type dumbbell is the viscosity number measured according to ISO307 (JIS-K6933), and specifically, 96. A sample solution prepared by dissolving the semi-aromatic polyamide (a) in the ISO multipurpose test piece A type dumbbell so as to have a concentration of 0.5% by mass in a sulfuric acid solution having a mass% concentration is filtered through a sintered glass filter. Then, using the filtered solution, the flow time of the sample solution at a temperature of 25 ° C. and the flow time of the solvent (concentrated sulfuric acid) at a temperature of 25 ° C. were measured with a Uberode type capillary viscosity meter, and the values obtained by the following relational expression. Is.
VN = (T ₁ / T _0-1 ) × (1 / C)
In the above formula, VN represents the viscosity number (mL / g), T ₀ represents the flow time (seconds) of the solvent (concentrated sulfuric acid), T ₁ represents the flow time (seconds) of the sample solution, and C represents the sample. It represents the concentration (g / ml) of the sample (semi-aromatic polyamide (a)) in the solution.

The intrinsic viscosity of the semi-aromatic polyamide (a) in the ISO multipurpose test piece A type dumbbell obtained by injection molding the polyamide resin composition of the present invention under the above conditions is excellent in hydrolysis resistance, mechanical strength and fatigue resistance. From the viewpoint of obtaining a body, it is preferably 0.90 dL / g or more, more preferably 1.00 dL / g or more, further preferably 1.05 dL / g or more, still more preferably 1.10 dL / g or more, and a polyamide resin. From the viewpoint of fluidity and moldability of the composition, it is preferably 1.6 dL / g or less, more preferably 1.4 dL / g or less, and further preferably 1.3 dL / g or less.
In the present invention, the intrinsic viscosity of the semi-aromatic polyamide (a) is a value measured and calculated specifically by the method described in Examples.

<Semi-aromatic polyamide (A)>
In the present invention, the semi-aromatic polyamide (A) is a polyamide containing a dicarboxylic acid unit containing an aromatic dicarboxylic acid unit as a main component and a diamine unit containing an aliphatic diamine unit as a main component, or an aliphatic dicarboxylic acid. A polyamide containing a dicarboxylic acid unit containing a unit as a main component and a diamine unit containing an aromatic diamine unit as a main component. Here, the term "main component" means that 50 to 100 mol%, preferably 60 to 100 mol%, of all the units are composed.
In the present specification, "-unit" (where "-" indicates a monomer) means "a structural unit derived from", and for example, "dicarboxylic acid unit" means "derived from dicarboxylic acid". It means "constituent unit", and "diamine unit" means "constituent unit derived from diamine".
The semi-aromatic polyamide (A) used in the present invention preferably contains a dicarboxylic acid unit containing an aromatic dicarboxylic acid unit as a main component and a diamine unit containing an aliphatic diamine unit as a main component.

(Dicarboxylic acid unit)
The dicarboxylic acid unit constituting the semi-aromatic polyamide (A) contains 50 aromatic dicarboxylic acid units from the viewpoint of obtaining a polyamide resin having excellent heat resistance and obtaining a molded product having excellent hydrolysis resistance and mechanical strength. It is preferably contained in an amount of about 100 mol%, more preferably 60 to 100 mol%, more preferably 75 to 100 mol%, still more preferably 90 to 100 mol%.

Examples of the aromatic dicarboxylic acid unit include terephthalic acid, naphthalenedicarboxylic acid, isophthalic acid, 1,4-phenylenedioxydiacetic acid, 1,3-phenylenedioxydiacetic acid, diphenylic acid, and diphenylmethane-4,4'-. Examples thereof include constituent units derived from dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, 4,4'-biphenyldicarboxylic acid and the like. These aromatic dicarboxylic acid units may contain one or more of the dicarboxylic acid units.
Among these, the aromatic dicarboxylic acid unit is preferably a structural unit derived from at least one selected from terephthalic acid and naphthalenedicarboxylic acid, and more preferably a structural unit derived from terephthalic acid. Therefore, the semi-aromatic polyamide (A) is preferably a constituent unit in which 50 to 100 mol% of the dicarboxylic acid unit is derived from at least one selected from terephthalic acid and naphthalenedicarboxylic acid, and is derived from terephthalic acid. It is more preferably a unit. Examples of the naphthalenedicarboxylic acid include 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and 1,4-naphthalenedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid is preferable.

The dicarboxylic acid unit constituting the semi-aromatic polyamide (A) may contain other dicarboxylic acid units other than the aromatic dicarboxylic acid unit, preferably in the range of less than 50 mol%.
Other dicarboxylic acid units include, for example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelli acid, suberic acid, azelaic acid, sebacic acid, undecandicarboxylic acid, dodecanedicarboxylic acid, dimethylmalonic acid, 2 , 2-diethylsuccinic acid, 2,2-dimethylglutaric acid, 2-methyladipic acid, trimethyladipic acid and other aliphatic dicarboxylic acids; 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1, Examples thereof include structural units derived from 4-cyclohexanedicarboxylic acid, cycloheptanedicarboxylic acid, cyclooctanedicarboxylic acid, alicyclic dicarboxylic acid such as cyclodecanedicarboxylic acid; and the like. These other dicarboxylic acid units may contain one or more dicarboxylic acid units. The content of these other dicarboxylic acid units in the dicarboxylic acid unit is preferably 25 mol% or less, and more preferably 10 mol% or less. The semi-aromatic polyamide (A) used in the present invention may further contain a structural unit derived from a polyvalent carboxylic acid such as trimellitic acid, trimesic acid, and pyromellitic acid within a range that allows melt molding.

(Diamine unit)
The diamine unit constituting the semi-aromatic polyamide (A) preferably contains 60 to 100 mol% of a constituent unit derived from an aliphatic diamine having 6 to 10 carbon atoms. When a semi-aromatic polyamide containing a structural unit derived from an aliphatic diamine having 6 to 10 carbon atoms (hereinafter, also referred to as an aliphatic diamine unit having 6 to 10 carbon atoms) in this ratio is used, heat resistance and moldability are used. An excellent polyamide resin composition can be obtained, and a molded product having excellent hydrolysis resistance and mechanical strength can be obtained. The diamine unit constituting the semi-aromatic polyamide (A) preferably contains 75 to 100 mol% of an aliphatic diamine unit having 6 to 10 carbon atoms, and further preferably 90 to 100 mol%.

Examples of the aliphatic diamine unit having 6 to 10 carbon atoms include 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, and 1,10-decanediamine. Linear aliphatic diamines; 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4- Examples of structural units derived from branched chain aliphatic diamines such as trimethyl-1,6-hexanediamine, 2-methyl-1,8-octanediamine, 5-methyl-1,9-nonanediamine; and the like can be mentioned. These aliphatic diamine units having 6 to 10 carbon atoms can contain one or more kinds of diamine units.

Aliphatic diamine units having 6 to 10 carbon atoms are 1,6-hexanediamine, 1,9-nonanediamine, 2-methyl-1,8- from the viewpoint of obtaining a molded product having excellent hydrolysis resistance and mechanical strength. It is preferably a structural unit derived from at least one selected from octanediamine and 1,10-decanediamine, preferably from 1,9-nonanediamine, 2-methyl-1,8-octanediamine and 1,10-decanediamine. It is preferably a structural unit derived from at least one selected.
Further, the aliphatic diamine unit is preferably a structural unit derived from the aliphatic diamine having 9 and 10 carbon atoms, and has 9 carbon atoms, from the viewpoint of obtaining a molded product having more excellent hydrolysis resistance and mechanical strength. More preferably, it is a structural unit derived from an aliphatic diamine. Specifically, it is more preferably a structural unit derived from at least one selected from 1,9-nonanediamine and 2-methyl-1,8-octanediamine, more preferably 1,9-nonanediamine and 2-methyl-1. , 8-octanediamine is even more preferred.

When the diamine unit contains both 1,9-nonanediamine and 2-methyl-1,8-octanediamine-derived constituent units, the 1,9-nonanediamine-derived constituent unit and 2-methyl-1,8-octanediamine From the viewpoint of moldability, the molar ratio of the structural unit derived from is the structural unit derived from 1,9-nonanediamine: the structural unit derived from 2-methyl-1,8-octanediamine = 99: 1 to 40:60. It is preferably in the range of 90:10 to 45:65, and even more preferably in the range of 85:15 to 50:50.

The diamine unit constituting the semi-aromatic polyamide (A) may contain other diamine units other than the aliphatic diamine unit having 6 to 10 carbon atoms, preferably in the range of less than 40 mol%.
Examples of other diamine units include ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 2-methyl-1,3-propanediamine and the like. Diamines having 5 or less carbon atoms; alicyclic diamines such as cyclohexanediamine, methylcyclohexanediamine, and isophoronediamine; p-phenylenediamine, m-phenylenediamine, xylylenediamine, 4,4'-diaminodiphenylmethane, 4, Examples thereof include structural units derived from aromatic diamines such as 4'-diaminodiphenyl sulfone and 4,4'-diaminodiphenyl ether. These other diamine units may contain one or more diamine units. The content of these other diamine-derived constituent units in the diamine unit is preferably 25 mol% or less, and more preferably 10 mol% or less.

The semi-aromatic polyamide (A) may further contain an aminocarboxylic acid unit as long as the effect of the present invention is not impaired.
Examples of the aminocarboxylic acid unit include structural units derived from 11-aminoundecanoic acid, 12-aminododecanoic acid and the like, and the aminocarboxylic acid unit may contain one or more. .. The content of the aminocarboxylic acid unit in the semi-aromatic polyamide (A) is preferably 40 mol% or less, preferably 20 mol%, based on 100 mol% of all the monomer units constituting the semi-aromatic polyamide (A). It is more preferably less than or equal to 10 mol% or less.

The semi-aromatic polyamide (A) may contain a lactam unit as long as the effect of the present invention is not impaired.
Examples of the lactam unit include constituent units derived from ε-caprolactam, enantractum, undecane lactam, lauryl lactam, α-pyrrolidone, α-piperidone and the like, and one or more lactam units are included. May be. The content of the lactam unit in the semi-aromatic polyamide (A) is preferably 40 mol% or less, preferably 20 mol% or less, based on 100 mol% of all the monomer units constituting the semi-aromatic polyamide. It is more preferably 10 mol% or less.

The semi-aromatic polyamide (A) used in the present invention contains a dicarboxylic acid unit and a diamine unit from the viewpoint of obtaining a molded product having excellent hydrolysis resistance and mechanical strength, and 50 to 100 mol% of the dicarboxylic acid unit is contained. It is a structural unit derived from at least one selected from terephthalic acid or naphthalenedicarboxylic acid, and it is preferable that 60 to 100 mol% of the diamine unit is a structural unit derived from an aliphatic diamine having 6 to 10 carbon atoms.

Polyhexamethylene terephthalamide is a typical semi-aromatic polyamide containing a dicarboxylic acid unit containing an aromatic dicarboxylic acid unit as a main component and a diamine unit containing an aliphatic diamine unit having 6 to 10 carbon atoms as a main component. (Polyamide 6T), Polyanonamethylene terephthalamide (Polyamide 9T), Poly (2-methyloctamethylene) terephthalamide (Nylon M8T), Polynonamethylene terephthalamide / Poly (2-methyloctamethylene) terephthalamide copolymer (Nylon 9T) / M8T), polynonamethylenenaphthalenedicarboxamide (polyamide 9N), polynonamethylenenaphthalenedicarboxamide / poly (2-methyloctamethylene) naphthalenedicarboxamide copolymer (nylon 9N / M8N), polydecamethylene terephthalamide (polyamide 10T) , Polyhexamethylene isophthalamide (polyamide 6I), polyamide 6I and polyamide 6T copolymer (polyamide 6I / 6T), polyamide 66 and polyamide 6I and polyamide 6T copolymer (polyamide 66 / polyamide 6I / 6T) , And a copolymer of polyamide 6T and polyamide 10T (polyamide 6T / 10T) and the like.
Among these, polynonamethylene naphthalenedicarboxamide (polyamide 9N), polynonamethylenenaphthalenedicarboxamide / poly (2-methyloctamethylene) naphthalenedicarboxamide copolymer (nylon 9N / M8N), polynonamethylene terephthalamide (polyamide 9T) , Polynonamethylene terephthalamide / poly (2-methyloctamethylene) terephthalamide copolymer (nylon 9T / M8T), and polydecamethylene terephthalamide (polyamide 10T), preferably at least one selected from polynonamethylenenaphthalenedicarboxamide. / Poly (2-methyloctamethylene) naphthalenedicarboxamide copolymer (nylon 9N / M8N), polynonamethylene terephthalamide (polyamide 9T), and polynonamethylene terephthalamide / poly (2-methyloctamethylene) terephthalamide copolymer (nylon) At least one selected from 9T / M8T) is more preferred, and is selected from polynonamethylene terephthalamide (polyamide 9T) and polynonamethylene terephthalamide / poly (2-methyloctamethylene) terephthalamide copolymer (nylon 9T / M8T). At least one of these is more preferred.

The semi-aromatic polyamide (A) used in the present invention preferably has 10 mol% or more of the terminal groups of the molecular chain sealed with a terminal sealant. The terminal encapsulation rate is more preferably 20 mol% or more, more preferably 30 mol% or more, from the viewpoint of obtaining a polyamide resin composition having excellent melt stability and obtaining a molded product having excellent hydrolysis resistance. Is even more preferable.
As a method for determining the terminal encapsulation rate of the semi-aromatic polyamide (A), for example, as shown in JP-A-7-228690, the intrinsic viscosity is measured and the relational expression between this and the number average molecular weight. The total amount of terminal groups is calculated from the above, and the amount of terminal amino groups and the amount of terminal carboxy groups obtained by titration are reduced from this method. Examples thereof include a method of measuring the number of terminal groups and obtaining the number based on the integrated value of the corresponding signal.

As the terminal encapsulant, a monofunctional compound having reactivity with a terminal amino group or a terminal carboxy group can be used. Specific examples thereof include monocarboxylic acids, acid anhydrides, monoisocyanates, monoacid halides, monoesters, monoalcohols and monoamines. From the viewpoint of reactivity and stability of the sealing terminal, a monocarboxylic acid is preferable as the terminal sealing agent for the terminal amino group, and a monoamine is preferable as the terminal sealing agent for the terminal carboxy group.

The monocarboxylic acid used as the terminal encapsulant is not particularly limited as long as it has reactivity with an amino group, and is, for example, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, capric acid, and laurin. Alicyclic monocarboxylic acids such as acids, tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, isobutylic acid; alicyclic monocarboxylic acids such as cyclopentanecarboxylic acid and cyclohexanecarboxylic acid; benzoic acid, toluic acid, Aromatic monocarboxylic acids such as α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, phenylacetic acid; any mixture thereof and the like can be mentioned. Among these, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, etc. , And at least one selected from valeric acid is preferred.

The monoamine used as the terminal sealant is not particularly limited as long as it has reactivity with a carboxy group, and is, for example, methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, and stearyl. Adipose monoamines such as amines, dimethylamines, diethylamines, dipropylamines and dibutylamines; alicyclic monoamines such as cyclohexylamines and dicyclohexylamines; aromatic monoamines such as aniline, toluidine, diphenylamines and naphthylamines; any mixture thereof and the like. Can be mentioned. Among these, at least one selected from butylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine, and aniline is preferable from the viewpoint of reactivity, high boiling point, stability of the sealed end, price, and the like.

The amount of terminal amino groups ([NH ₂ ]) of the molecular chain of the semi-aromatic polyamide (A) used in the present invention is preferably 10 μe equivalent / g or more, more preferably from the viewpoint of obtaining a molded product having excellent hydrolysis resistance. Is 20 μe equivalent / g or more, more preferably 30 μe equivalent / g or more, and as the amount of terminal amino groups increases, cross-linking is likely to occur during molding, and the fluidity of the polyamide resin composition deteriorates, resulting in poor moldability. Since it decreases, it is preferably 120 μe equivalent / g or less, more preferably 110 μe equivalent / g or less, and further preferably 100 μe equivalent / g or less.
In the present invention, the amount of terminal amino groups ([NH ₂ ]) refers to the amount of terminal amino groups (unit: μ equivalent / g) contained in 1 g of the semi-aromatic polyamide (A), and is measured by the following method. It is a value calculated and calculated.
First, 30 mL of phenol is added to 1 g of semi-aromatic polyamide (A), heated to 110 ° C. to dissolve it, and then 2 mL of methanol is added and mixed to prepare a sample solution. Subsequently, using thymol blue as an indicator, titration using 0.01 equivalent / L hydrochloric acid aqueous solution was carried out using the sample solution, and the amount of terminal amino groups of the semi-aromatic polyamide (A) ([NH ₂ ], Unit: μ equivalent / g) is calculated.

The terminal carboxy group ([COOH]) of the molecular chain of the semi-aromatic polyamide (A) used in the present invention is the strength of the molded product as the adhesion between the semi-aromatic polyamide (A) and the inorganic filler (B) is improved. From the viewpoint of improvement and heat resistance, it is preferably 1 μe equivalent / g or more, more preferably 5 μe equivalent / g or more, still more preferably 8 μe equivalent / g or more, and is preferable from the viewpoint of obtaining a molded product having excellent hydrolysis resistance. Is 60 μe equivalent / g or less, more preferably 50 μe equivalent / g or less, still more preferably 40 μe equivalent / g or less.
In the present invention, the amount of the terminal carboxy group ([COOH]) refers to the amount of the terminal carboxy group (unit: μ equivalent) contained in 1 g of the semi-aromatic polyamide (A), and is measured and calculated by the following method. Is the value to be.
First, 40 mL of cresol is added to 0.5 g of semi-aromatic polyamide and heated to 130 ° C. to dissolve the sample solution. Subsequently, using the sample solution, titration using a 0.01 equivalent / L potassium hydroxide aqueous solution was carried out by a potential difference automatic titration device (MCU-710) manufactured by Kyoto Electronics Manufacturing Co., Ltd., and the amount of carboxy group was increased. ([COOH], unit: μ equivalent / g) is calculated.

The terminal amino group amount ([NH ₂ ] (μ equivalent / g)) and the terminal carboxy group amount ([COOH] (μ equivalent / g)) of the molecular chain of the semi-aromatic polyamide (A) of the present invention are as follows. (I) is satisfied.
1 ≦ [NH ₂ ] / [COOH] <6 (I)
By satisfying the above formula (I), that is, when the value obtained by dividing the amount of terminal amino groups by the amount of terminal carboxy groups is 1 or more and less than 6, a molded product having excellent hydrolysis resistance can be obtained.
The value obtained by dividing the amount of the terminal amino group by the amount of the terminal carboxy group is preferably 1.5 or more, more preferably 2.0 or more, still more preferably 2.5 or more, from the viewpoint of obtaining a molded product having better hydrolysis resistance. , More preferably 3.0 or more, preferably 5.9 or less, more preferably from the viewpoint of obtaining a molded product having excellent heat resistance and water resistance, and from the viewpoint of moldability and retention stability during molding of the polyamide resin composition. Is 5.8 or less, more preferably 5.7 or less, still more preferably 5.6 or less.

The terminal amino group amount ([NH ₂ ] (μ equivalent / g)) and the terminal carboxy group amount ([COOH] (μ equivalent / g)) of the molecular chain of the semi-aromatic polyamide (A) of the present invention are given by the above formulas. By satisfying (I), the following formula (II) is also satisfied.
[NH ₂ ]-[COOH] ≧ 0 (II)
By satisfying the above formula (II), that is, when the value obtained by subtracting the terminal carboxy group amount from the terminal amino group amount is 0 μe equivalent / g or more, a molded product having excellent hydrolysis resistance can be obtained.
The value obtained by subtracting the amount of the terminal carboxy group from the amount of the terminal amino group is preferably 10 μe equivalent / g or more, more preferably 20 μe equivalent / g or more, and is a semi-aromatic polyamide from the viewpoint of obtaining a molded product having more excellent hydrolysis resistance. From the viewpoint of improving the strength and heat resistance of the molded product due to the improvement of the adhesion between (A) and the inorganic filler (B), and from the viewpoint of the moldability of the polyamide resin composition and the retention stability during molding, an amount of 90 μe is preferable. It is / g or less, more preferably 80 μe equivalent / g or less.

The intrinsic viscosity of the semi-aromatic polyamide (A) used in the present invention is preferably 0.9 dl / g or more, preferably 1.0 dl / g, from the viewpoint of obtaining a molded product having excellent hydrolysis resistance and mechanical strength. It is more preferably g or more, further preferably 1.1 dl / g or more, further preferably 1.15 dl / g or more, and from the viewpoint of moldability and fluidity of the polyamide resin, 1. It is preferably 6 dl / g or less, more preferably 1.4 dl / g or less, and even more preferably 1.3 dl / g or less.
In the present invention, the intrinsic viscosity of the semi-aromatic polyamide (A) is a value measured under the condition of 30 ° C. in concentrated sulfuric acid, and specifically, it is measured and calculated by the method described in Examples. The value.

The melting point of the semi-aromatic polyamide (A) used in the present invention is not particularly limited and may be, for example, 240 ° C. or higher and 250 ° C. or higher, but the effect of the present invention is more pronounced. It is preferably 260 ° C. or higher. The upper limit of the melting point of the semi-aromatic polyamide (A) is not particularly limited, but from the viewpoint of moldability of the polyamide resin composition, it is preferably 320 ° C. or lower, and more preferably 310 ° C. or lower. The melting point of the semi-aromatic polyamide (A) can be determined as the peak temperature of the melting peak that appears when the temperature is raised at a rate of 10 ° C./min using a differential scanning calorimetry (DSC) device, and more specifically. It can be obtained by the method described in the examples.

The polyamide resin composition of the present invention preferably contains 50 to 80% by mass of the semi-aromatic polyamide (A) with respect to 100% by mass of the polyamide resin composition. When the content of the semi-aromatic polyamide (A) is 50% by mass or more, the polyamide resin composition can exhibit sufficient heat resistance, and when it is 80% by mass or less, the molding is excellent in mechanical strength. You can get a body. The content of the semi-aromatic polyamide (A) is preferably 55% by mass or more, more preferably 60% by mass or more, from the viewpoint of obtaining a polyamide resin composition having more excellent heat resistance with respect to 100% by mass of the polyamide resin composition. From the viewpoint of obtaining a molded product that is preferable and has more excellent mechanical strength, 75% by mass or less is preferable, and 70% by mass or less is more preferable.

(Method for producing semi-aromatic polyamide (A))
The semi-aromatic polyamide (A) of the present invention can be produced by any method known as a method for producing a polyamide, for example, a melt polymerization method using a dicarboxylic acid and a diamine as raw materials, a solid phase. It can be produced by a method such as a polymerization method or a melt extrusion polymerization method. Among these, the solid phase polymerization method is preferable from the viewpoint of better suppressing thermal deterioration during polymerization.

The semi-aromatic polyamide (A) is prepared at a temperature of 200 to 250 ° C., for example, by first adding a diamine, a dicarboxylic acid, and if necessary, a catalyst and a terminal encapsulant all at once to produce a nylon salt. It can be produced by heat polymerization to obtain a prepolymer and further solid-phase polymerization or polymerization using a melt extruder. When the final stage of the polymerization is carried out by solid phase polymerization, it is preferably carried out under reduced pressure or under an inert gas flow, and when the polymerization temperature is in the range of 200 to 280 ° C., the polymerization rate is high and the productivity is excellent. Coloring and gelation can be effectively suppressed. When the final stage of the polymerization is carried out by a melt extruder, the polymerization temperature is preferably 370 ° C. or lower, and when the polymerization is carried out under such conditions, a semi-aromatic polyamide (A) with almost no decomposition and little deterioration can be obtained. ..

When producing the semi-aromatic polyamide (A), phosphoric acid, phosphorous acid, hypophosphoric acid, salts thereof, esters and the like can be added as a catalyst. Examples of the salt or ester include phosphoric acid, phosphoric acid or hypophosphoric acid, and potassium, sodium, magnesium, vanadium, calcium, zinc, cobalt, manganese, tin, tungsten, germanium, titanium, antimony and the like. Salt with metal; phosphoric acid, phosphoric acid or ammonium salt of hypophosphoric acid; phosphoric acid, phosphoric acid or hypophosphoric acid ethyl ester, isopropyl ester, butyl ester, hexyl ester, isodecyl ester, octadecyl ester , Decyl ester, stearyl ester, phenyl ester and the like.
The amount of the catalyst used is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, and more preferably 1.0, based on 100% by mass of the semi-aromatic polyamide (A). It is preferably 1% by mass or less, and more preferably 0.5% by mass or less. If the amount of the catalyst used is not less than the above lower limit, the polymerization proceeds satisfactorily. If it is not more than the above upper limit, impurities derived from the catalyst are less likely to occur, and for example, when the polyamide resin composition containing the semi-aromatic polyamide (A) is extruded, defects due to the impurities can be prevented.

<Inorganic filler (B)>
The polyamide resin composition in the present invention contains 10 to 200 parts by mass of the inorganic filler (B) with respect to 100 parts by mass of the semi-aromatic polyamide (A). By containing the inorganic filler (B), a polyamide resin composition capable of producing a molded product having excellent mechanical strength can be obtained.

The inorganic filler (B) used in the present invention is not particularly limited, and known ones can be used as long as the effects of the present invention are not impaired.
Examples of the inorganic filler (B) include fibrous fillers such as glass fiber, carbon fiber, calcium silicate fiber, potassium titanate fiber, and aluminum borate fiber; glass flakes, talc, kaolin, mica, silicon nitride, and the like. Hydrotalcite, calcium carbonate, zinc carbonate, titanium oxide, calcium monohydrogen phosphate, wollastonite, silica, zeolite, alumina, boehmite, aluminum hydroxide, calcium silicate, sodium aluminosilicate, magnesium silicate, Ketjen black , Acetylene black, furnace black, carbon nanotubes, graphite, graphene, brass, copper, silver, aluminum, nickel, iron, calcium fluoride, montmorillonite, swellable fluorine mica, apatite and the like. One of these inorganic fillers (B) may be used alone, or two or more thereof may be used in combination.

Among the above-mentioned inorganic fillers (B), fibrous fillers, glass flakes, talc, kaolin, mica, calcium carbonate, from the viewpoint of moldability of the polyamide resin composition and from the viewpoint of obtaining a molded product having excellent mechanical strength. At least one selected from calcium monohydrogen phosphate, wollastonite, silica, carbon nanotubes, graphite, calcium fluoride, montmorillonite, swellable fluorine mica, and apatite is preferred, and fibrous fillers, wollastonite, and mica. At least one selected from the above is more preferable, and a fibrous filler is further preferable. Further, among the fibrous fillers, at least one selected from glass fiber and carbon fiber is preferable, and glass fiber is more preferable. Therefore, the inorganic filler (B) is preferably at least one selected from glass fibers and carbon fibers, and more preferably glass fibers.

The average fiber diameter of the fibrous filler is usually about 0.5 to 250 μm, but from the viewpoint of improving the contact area with the semi-aromatic polyamide (A) and increasing the mechanical strength of the obtained molded product, 3 It is preferably up to 100 μm, more preferably 3 to 30 μm. The average fiber length of the fibrous filler used is usually about 0.1 to 10 mm, but from the viewpoint of increasing the high temperature strength, heat resistance, and mechanical strength of the polyamide resin composition, it is 0.2 to 6 mm. Is preferable, and 1 to 6 mm is more preferable. The aspect ratio (L / D) between the average fiber length and the average fiber diameter is preferably 10 to 500.
A fibrous filler having a combination of any two or more of these average fiber diameters, average fiber lengths, and aspect ratios is excellent in high temperature strength, heat resistance, mechanical strength, and the like of the polyamide resin composition. Further preferred from the point of view.
The average fiber diameter and average fiber length of the fibrous filler can be observed and measured with an optical microscope.
Further, the cross-sectional shape of the fibrous filler is not particularly limited, and may be square, circular, or flat. Examples of the flat cross-sectional shape include a rectangle, an oval shape close to a rectangle, an ellipse, a cocoon shape, and a cocoon shape having a constricted central portion in the longitudinal direction.

The inorganic filler (B) may be surface-treated with a silane coupling agent, a titanate-based coupling agent, or the like, if necessary. The silane coupling agent is not particularly limited, but is an aminosilane type such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane. Coupling agents; mercaptosilane-based coupling agents such as γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane; epoxysilane-based coupling agents; vinylsilane-based coupling agents and the like can be mentioned. One of these silane coupling agents may be used alone, or two or more thereof may be used in combination. Among the above silane coupling agents, aminosilane-based coupling agents are preferable.

The inorganic filler (B), preferably the fibrous filler, may be treated with a sizing agent, if necessary. As the sizing agent, for example, a copolymer containing a carboxylic acid anhydride-containing unsaturated vinyl monomer unit and an unsaturated vinyl monomer unit excluding the carboxylic acid anhydride-containing unsaturated vinyl monomer as a constituent unit. Examples thereof include epoxy compounds, polyurethane resins, homopolymers of acrylic acid, copolymers of acrylic acid and other copolymerizable monomers, salts with primary, secondary or tertiary amines thereof and the like. These sizing agents may be used alone or in combination of two or more.

The content of the inorganic filler (B) with respect to 100 parts by mass of the semi-aromatic polyamide (A) in the polyamide resin composition of the present invention is 10 to 200 parts by mass. When the content of the inorganic filler (B) is 10 parts by mass or more, the mechanical strength improving effect of the inorganic filler (B) can be easily imparted to the polyamide resin composition. Further, when the content of the inorganic filler (B) is 200 parts by mass or less, the moldability of the polyamide resin composition becomes good. The content of the inorganic filler (B) is preferably 15 parts by mass or more, more preferably 20 parts by mass or more, further preferably 25 parts by mass or more, and 35 parts by mass or more from the viewpoint of obtaining a molded product having better mechanical strength. Is more preferably, 45 parts by mass or more is further preferable, and from the viewpoint of obtaining a polyamide resin composition having more excellent moldability, 140 parts by mass or less is preferable, 120 parts by mass or less is more preferable, and 100 parts by mass or less is preferable. Even more preferably, 80 parts by mass or less is even more preferable.

<Organic Antioxidant (C)>
The polyamide composition of the present invention preferably contains an organic antioxidant (C) in addition to the semi-aromatic polyamide (A) and the inorganic filler (B). By containing the organic antioxidant (C), the heat aging resistance is improved.
Examples of the organic antioxidant (C) include a phenol-based antioxidant, a phosphorus-based antioxidant, a sulfur-based antioxidant, an amine-based antioxidant, and the like. One of these antioxidants may be used alone, or two or more thereof may be used in combination. Among these, at least one selected from a phenol-based antioxidant and an amine-based antioxidant is preferable, and a phenol-based antioxidant is more preferable, from the viewpoint of obtaining a molded product having excellent hydrolysis resistance.
The polyamide resin composition preferably contains 0.01 to 5% by mass, preferably 0.05 to 3% by mass of the organic antioxidant (C) with respect to 100 parts by mass of the semi-aromatic polyamide (A). Is more preferable, and it is further preferable to contain 0.1 to 2% by mass. When the content of the organic antioxidant (C) is within the above range, a polyamide resin composition with a small amount of gas generated during extrusion molding can be obtained, and molding having excellent hydrolysis resistance and heat aging resistance can be obtained. You can get a body.

Examples of the phenol antioxidant include hindered phenol compounds. The hindered phenol compound has the property of improving the hydrolysis resistance and heat aging resistance of the obtained molded product, and imparting heat resistance and light resistance to the polyamide resin composition.
Examples of the hindered phenol compound include 2,2-thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], N, N'-hexane-1,6- Diylbis [3- (3,5-di-tert-butyl-4-hydroxyphenylpropionamide), pentaerythrityl-tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], N, N'-hexamethylenebis (3,5-di-tert-butyl-4-hydroxyphenyl) propionamide, triethylene glycolbis (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate, hexa Methylenebis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), 3,9-bis {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) ) Propionyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5.5] undecane, tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate , 3,5-Di-tert-butyl-4-hydroxybenzylphosphonate-diethyl ester, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) ) Benzyl, 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid and the like.

The phenolic antioxidants are N, N'-hexamethylenebis (3,5-di-tert-butyl-4-hydroxyphenyl) propionamide and 3,9 from the viewpoint of heat resistance of the obtained polyamide resin composition. -Bis {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] -1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5. 5] At least one selected from undecane is preferable.

Examples of the phosphorus-based antioxidant include monosodium phosphate, disodium phosphate, trisodium phosphate, sodium phosphite, calcium phosphite, magnesium phosphite, manganese phosphite, pentaerythritol-type phosphite compound, and bird. Octylphosphite, trilaurylphosphite, octyldiphenylphosphite, trisisodecylphosphite, phenyldiisodecylphosphite, phenyldi (tridecyl) phosphite, diphenylisooctylphosphite, diphenylisodecylphosphite, diphenyl (tridecyl) phosphite , Triphenylphosphite, trioctadecylphosphite, tridecylphosphite, tri (nonylphenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite, tris (2,4-di-tert-) Butyl-5-methylphenyl) phosphite, tris (butoxyethyl) phosphite, 4,4'-butylidene-bis (3-methyl-6-tert-butylphenyl-tetratridecyl) diphosphite, tetra (C12-C15 mixture) Alkyl) -4,4'-isopropyridene diphenyl diphosphite, 4,4'-isopropyridenebis (2-tert-butylphenyl) di (nonylphenyl) phosphite, tris (biphenyl) phosphite, tetra (tridecyl) )-1,1,3-Tris (2-methyl-5-tert-butyl-4-hydroxyphenyl) butanediphosphite, tetra (tridecyl) -4,4'-butylidenebis (3-methyl-6-tert-) Butylphenyl) diphosphite, tetra (C1-C15 mixed alkyl) -4,4'-isopropylidene diphenyldiphosphite, tris (mono, dimixed nonylphenyl) phosphite, 4,4'-isopropylidenebis (2-tert) -Butylphenyl) di (nonylphenyl) phosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, tris (3,5-di-tert-butyl-4-hydroxy) Phosphorus phosphite, hydrogenation-4,4'-isopropyridene diphenylpolyphosphite, bis (octylphenyl), bis (4,4'-butylidenebis (3-methyl-6-tert-butylphenyl)), 1, 6-hexanoldiphosphite, hexatridecyl-1,1,3-tris (2-methyl-4-hide) Roxy-5-tert-butylphenyl) diphosphite, tris (4,4'-isopropylidenebis (2-tert-butylphenyl)) phosphite, tris (1,3-stearoyloxyisopropyl) phosphite, 2,2- Methylenebis (4,6-di-tert-butylphenyl) octylphosphite, 2,2-methylenebis (3-methyl-4,6-di-tert-butylphenyl) -2-ethylhexylphosphite, tetrakis (2,4) -Di-tert-butyl-5-methylphenyl) -4,4'-biphenylenediphosphite, tetrakis (2,4-di-tert-butylphenyl) -4,4'-biphenylenediphosphite, 6- [ 3- (3-tert-Butyl-4-hydroxy-5-methylphenyl) propoxy] -2,4,8,10-tetra-tert-butyldibenzo [d, f] [1,3,2] -dioxa Phosfepine and the like can be mentioned.

Examples of sulfur-based antioxidants include distearyl 3,3'-thiodipropionate, pentaerythrityltetrakis (3-laurylthiopropionate), 2-mercaptobenzimidazole, and didodecyl 3,3'-thiodipropio. Nate, ditridecyl 3,4'-thiodipropionate, 2,2-bis [[3- (dodecylthio) -1-oxopropoxy] methyl] -1,3-propanediyl ester and the like can be mentioned.

Examples of the amine-based antioxidant include 4,4'-bis (α, α-dimethylbenzyl) diphenylamine (“Nocrack CD” manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd., “Naugard 445” manufactured by Adiband Japan Co., Ltd., etc.). N, N'-di-2-naphthyl-p-phenylenediamine ("Nocrack White" manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd., etc.), N, N'-diphenyl-p-phenylenediamine (Ouchi Shinko Kagaku Kogyo Co., Ltd.) "Nocrack DP", etc.), N-phenyl-1-naphthylamine ("Nocrack PA", etc., manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.), N-phenyl-N'-isopropyl-p-phenylenediamine (Ouchi Shinko Kagaku Kogyo Co., Ltd.) "Nocrack 810-NA" manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.), N-phenyl-N'-(1,3-dimethylbutyl) -p-phenylenediamine ("Nocrack 6C" manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.), N- Phenyl-N'-(3-methacryloyloxy-2-hydroxypropyl) -p-phenylenediamine ("Nocrack G-1" manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd., etc.), 4-acetoxy-2,2,6,6 -Tetramethylpiperidine, 4-stearoyloxy-2,2,6,6-tetramethylpiperidine, 4-acryloyloxy-2,2,6,6-tetramethylpiperidine, 4- (phenylacetoxy) -2,2 6,6-Tetramethylpiperidin, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, 4-methoxy-2,2,6,6-tetramethylpiperidine, 4-stearyloxy-2,2 6,6-Tetramethylpiperidine, 4-cyclohexyloxy-2,2,6,6-tetramethylpiperidine, 4-benzyloxy-2,2,6,6-tetramethylpiperidine, 4-phenoxy-2,2 6,6-Tetramethylpiperidin, 4- (ethylcarbamoyloxy) -2,2,6,6-tetramethylpiperidin, 4- (cyclohexylcarbamoyloxy) -2,2,6,6-tetramethylpiperidin, 4- (Phenylenecarbamoyloxy) -2,2,6,6-tetramethylpiperidin, bis (2,2,6,6-tetramethyl-4-piperidyl) carbonate, bis (2,2,6,6-tetramethyl-) 4-piperidyl) oxalate, bis (2,2,6,6-tetramethyl-4-piperidyl) malonate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (2,2) 6,6 -Tetramethyl-4-piperidyl) adipate, bis (2,2,6,6-tetramethyl-4-piperidyl) terephthalate, 1,2-bis (2,2,6,6-tetramethyl-4-piperidyloxy) ) Etan, α, α'-bis (2,2,6,6-tetramethyl-4-piperidyloxy) -p-xylene, bis (2,2,6,6-tetramethyl-4-piperidyl) trilen- 2,4-dicarbamate, bis (2,2,6,6-tetramethyl-4-piperidyl) hexamethylene-1,6-dicarbamate, tris (2,2,6,6-tetramethyl-4-piperidyl) ) Benzene-1,3,5-tricarboxylate, Tris (2,2,6,6-tetramethyl-4-piperidyl) benzene-1,3,4-tricarboxylate, 1- [2- {3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy} butyl] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] 2,2 6,6-Tetramethylpiperidine, 1,2,3,4-butanetetracarboxylic acid and 1,2,2,6,6-pentamethyl-4-piperidinol and β, β, β', β'-tetramethyl- Examples thereof include a condensate with 3,9- [2,4,8,10-tetraoxaspiro [5.5] undecane] diethanol.

The amine-based antioxidant is preferably 4,4'-bis (α, α-dimethylbenzyl) diphenylamine from the viewpoint of heat resistance of the obtained polyamide resin composition.

<Other ingredients>
In addition to the semi-aromatic polyamide (A), the inorganic filler (B) and the organic antioxidant (C), the polyamide resin composition of the present invention contains, if necessary, a crystal nucleating agent, a coloring agent, and a mold release agent. , Inorganic antioxidants, plasticizers, lubricants, flame retardants, flame retardants, antistatic agents, crystallization retarders and the like.

The crystal nucleating agent is not particularly limited as long as it is generally used as a crystal nucleating agent for polyamide, and for example, talc, calcium stearate, aluminum stearate, barium stearate, zinc stearate, antimony oxide, and oxidation. Examples include magnesium, any mixture thereof and the like. Of these, talc is preferred. The crystal nucleating agent may be treated with a silane coupling agent, a titanium coupling agent, or the like.

The colorant is not particularly limited and can be appropriately selected from inorganic or organic pigments and dyes according to the use of the polyamide resin composition. Examples of the inorganic pigments include black inorganic pigments such as carbon black, lamp black, acetylene black, bone black, thermal black, channel black, furnace black, and titanium black, and titanium oxide (TIO, Ti ₂ O ₃ , TIO ₂ ). Metal oxides such as zinc oxide (Pb ₃ O ₄ ), iron oxide (Fe ₂ O ₃ ), antimony oxide, zirconium oxide (zircon oxide), Ultramarin (Pigment Blue 29), zinc sulfide, zinc phosphate, barium sulfate. , Manganese phosphate, cobalt aluminate, cobalt tinate, cobalt zincate, antimony oxide, antimony sulfide, cerium sulfide, lanthanum sulfide, chromium oxide, zinc chromate, nickel, bismuth, vanadium, molybdenum, cadmium , Titanium-based, zinc-based, manganese-based, cobalt-based, iron-based, chromium-based, antimony-based, magnesium-based, aluminum-based, and other composite metal oxides containing a plurality of oxides.
Examples of the organic pigment include azo pigments such as azo lake pigments, insoluble mono azo pigments, insoluble disazo pigments and chelate azo pigments, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments and dioxazine pigments. Examples thereof include organic pigments such as thioindigo pigments, isoindolinone pigments, quinophthalone pigments, diketopyrrolopyrrole pigments, benzimidazolone pigments and slen pigments.
Among these, inorganic pigments are preferable, carbon black is more preferable, and carbon black is more preferably contained in an amount of 0.2 to 1.6% by mass with respect to 100 parts by mass of the semi-aromatic polyamide (A).

Examples of the mold release agent include silicone-based, fluorine-based, long-chain alkyl-based, fatty acid amide-based, and the like.

Examples of the inorganic antioxidant include potassium ferrocyanide, potassium ferricyanide, cerium hydroxide and the like.

The polyamide resin composition of the present invention preferably has a copper compound content of less than 1 part by mass, more preferably less than 0.1 part by mass, based on 100 parts by mass of the semi-aromatic polyamide (A). It is more preferably less than 0.01 parts by mass, and even more preferably substantially free of copper compounds. When the content of the copper compound in the polyamide resin composition of the present invention is in the above range or the polyamide resin composition does not substantially contain the copper compound, a molded product having more excellent hydrolysis resistance can be obtained.
Examples of the copper compound include copper halides such as copper iodide and copper bromide.
Further, the polyamide resin composition of the present invention preferably contains less than 1 part by mass of potassium halide with respect to 100 parts by mass of the semi-aromatic polyamide (A), and more preferably less than 0.1 part by mass. It is more preferably less than 0.01 parts by mass, and even more preferably substantially free of potassium halide.
Examples of the potassium halide include potassium iodide, potassium bromide and the like.

<Manufacturing method of polyamide resin composition>
The method for producing the polyamide resin composition is not particularly limited, and the semi-aromatic polyamide (A) and the inorganic filler (B), and the above-mentioned organic antioxidant seat (C) and other components used as necessary are used as necessary. A method capable of uniformly mixing the above can be preferably adopted. For mixing, a method of melt-kneading using a single-screw extruder, a twin-screw extruder, a kneader, a Banbury mixer, or the like is usually preferably adopted. The melt-kneading conditions are not particularly limited, but for example, melt-knead for about 1 to 30 minutes in a temperature range of about 10 to 60 ° C. higher than the melting point of the semi-aromatic polyamide (A) to obtain a pelletized polyamide resin composition. The method can be mentioned.

[Molded product]
The molded product of the present invention is a molded product of the above-mentioned polyamide resin composition. A molded product can be obtained by producing the above-mentioned polyamide resin composition, for example, pelletized one, and then subjecting it to various molding methods. The molding method of the molded body may be appropriately selected depending on the intended use, but methods such as injection molding, extrusion molding, hollow molding, compression molding, press molding, and calendar molding can be adopted.
Since the molded body of the present invention has excellent hydrolysis resistance and mechanical strength, parts for automobiles, particularly parts that come into contact with LLC, such as tubes, connectors, thermostat housings, radiator tanks, radiator hoses, water inlets, and water outlets. , Water pump housing, rear joint, coolant control valve housing, thermal management module housing and the like.

Further, when the initial tensile strength of the molded product of the present invention is 170 MPa or more, the molded product has good mechanical strength as an LLC contact part from the viewpoint of water pressure resistance and the like, and can be put into practical use. The initial tensile strength is preferably 175 MPa or more, more preferably 180 MPa or more, still more preferably 185 MPa or more.
The initial tensile strength is a value measured in accordance with ISO527-1 (2012 2nd edition), and more specifically, a value measured by the method described in Examples.

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

[Measurement of physical properties]
The measurement of each physical property in the production example, the example, and the comparative example was performed according to the method shown below.

(Amount of terminal amino group)
30 mL of phenol was added to 1 g of the semi-aromatic polyamide obtained in the production example, heated to 110 ° C. to dissolve it, and then 2 mL of methanol was added and mixed to prepare a sample solution. Using thymol blue as an indicator, titration using 0.01 equivalent / L hydrochloric acid aqueous solution was carried out using the sample solution, and the terminal amino group amount ([NH ₂ ], unit: μ equivalent / g) of the semi-aromatic polyamide. ) Was calculated.

(Amount of terminal carboxy group)
40 mL of cresol was added to 0.5 g of the semi-aromatic polyamide obtained in the production example, and the mixture was heated to 130 ° C. to dissolve it to prepare a sample solution. Subsequently, using the sample solution, titration using a 0.01 equivalent / L potassium hydroxide aqueous solution was carried out by a potential difference automatic titration device (MCU-710) manufactured by Kyoto Electronics Manufacturing Co., Ltd., and the amount of carboxy group was increased. ([COOH], unit: μ equivalent / g) was calculated.

(Intrinsic viscosity of semi-aromatic polyamide (A))
A sample solution was prepared by dissolving the semi-aromatic polyamide obtained in the production example at a concentration of 0.2 g / dl using concentrated sulfuric acid as a solvent. Next, the flowing time of the solvent (concentrated sulfuric acid) and the flowing time of the sample solution at a temperature of 30 ° C. were measured, and the intrinsic viscosity was obtained from the following formula.
η _inh = [ln (t ₁ / t ₀ )] / c
In the above relational expression, t ₀ represents the flow time (seconds) of the solvent (concentrated sulfuric acid), t ₁ represents the flow time (seconds) of the sample solution, and c represents the sample (semi-aromatic polyamide (A)) in the sample solution. )) Concentration (g / dl).

(Melting point)
The melting point of the semi-aromatic polyamide obtained in the production example was measured using a differential scanning calorimetry apparatus "DSC7020" manufactured by Hitachi High-Tech Science Co., Ltd.
The melting point was measured according to ISO11357-3 (2011 2nd edition). Specifically, the sample (semi-aromatic polyamide) is heated from 30 ° C. to 340 ° C. at a rate of 10 ° C./min under a nitrogen atmosphere and held at 340 ° C. for 5 minutes to completely melt the sample. The sample was cooled to 50 ° C. at a rate of 10 ° C./min and held at 50 ° C. for 5 minutes. The peak temperature of the melting peak that appears when the temperature is raised to 340 ° C again at a rate of 10 ° C / min is defined as the melting point (° C), and when there are multiple melting peaks, the peak temperature of the melting peak on the highest temperature side is defined as the melting point (° C). did.

(Preparation of ISO multipurpose test piece A type dumbbell)
Using the pellet-shaped polyamide resin composition obtained in Examples and Comparative Examples, an injection molding machine (manufactured by Sumitomo Heavy Industries, Ltd., mold clamping force: 100 tons, screw diameter: 32 mm) was used, and a cylinder was used. ISO multipurpose test piece A type dumbbell (4 mm thick, total length), which is a polyamide resin composition molded product molded by a T-runner mold under the conditions of a temperature of 320 ° C., a mold temperature of 140 ° C., and a cycle time of 40 seconds or less. 170 mm, parallel portion length 80 mm, parallel portion width 10 mm) were produced.

(Number average molecular weight and weight average molecular weight of semi-aromatic polyamide (a) in ISO multipurpose test piece A type dumbbell)
The number average molecular weight and weight average molecular weight of the semi-aromatic polyamide (a) in the ISO multipurpose test piece A type dumbbell were determined by using the ISO multipurpose test piece A type dumbbell (test piece) obtained in Examples and Comparative Examples. It was determined by gel permeation chromatography (GPC) as a standard polymethylmethacrylate-equivalent molecular weight.
As the eluent, an HFIP solution in which sodium trifluoroacetate was dissolved at a ratio of 0.85 g to 1 kg of 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) was used.
The ISO multipurpose test piece A type dumbbell was cut and sampled to 1.5 mg in terms of resin (polyamide resin), and dissolved in 3 mL of the above eluent. The solution was filtered through a 0.4 μm membrane filter to prepare a measurement sample. The number average molecular weight and the weight average molecular weight were measured under the following measurement conditions.
(Measurement condition)
Equipment: HLC-8320GPC (manufactured by Tosoh Corporation)
Column: Two TSKgel SuperHM-N (manufactured by Tosoh Corporation) were connected in series.
Eluent: 0.085% sodium trifluoroacetate / HFIP solution Flow velocity: 0.4 mL / min (reference column: 0.2 mL / min)
Sample injection volume: 10 μL
Column temperature: 40 ° C
Standard Polymethylmethacrylate: Shodex Standard
M-75 (manufactured by Showa Denko KK), Polymethascryla (Agilent Technologies, Inc.)
te Molecular weight 1010 Polymethylmethacrylate detector: UV (254nm) detector

(Intrinsic viscosity of semi-aromatic polyamide (a) in ISO multipurpose test piece A type dumbbell)
By the same method as the measurement of the intrinsic viscosity of the semi-aromatic polyamide (A), the intrinsic viscosities of the following resins 1 to 7 having different weight average molecular weights were measured under the condition of 30 ° C. in concentrated sulfuric acid. The results are shown below.
Resin 1 (weight average molecular weight 7960): intrinsic viscosity 0.60
Resin 2 (weight average molecular weight 11800): intrinsic viscosity 0.78
Resin 3 (weight average molecular weight 15100): intrinsic viscosity 0.90
Resin 4 (weight average molecular weight 18900): intrinsic viscosity 1.03
Resin 5 (weight average molecular weight 25900): intrinsic viscosity 1.22
Resin 6 (weight average molecular weight 28500): intrinsic viscosity 1.26
Resin 7 (weight average molecular weight 38500): intrinsic viscosity 1.35
Further, from the weight average molecular weight of the semi-aromatic polyamide (a) in the obtained ISO multipurpose test piece A type dumbbell, the semi-aromatic polyamide (a) in the ISO multipurpose test piece A type dumbbell can be obtained from the following formula (1). The intrinsic viscosity of was determined.
η = -3.172 × 10 ^-15 × M ³ -5.330 × 10 ^-10 × M ² ＋5.511 × 10 ^-5 × M ＋0.2008 (1)
In the above relational expression, η represents the intrinsic viscosity of the semi-aromatic polyamide (a) in the ISO multipurpose test piece A type dumbbell, and M is the weight average of the semi-aromatic polyamide (a) in the ISO multipurpose test piece A type dumbbell. Represents the molecular weight.
It should be noted that the coefficient of determination calculated from the η obtained from the intrinsic viscosity of the obtained resins 1 to 7 and the weight average molecular weight, which represents the degree of fitting of the estimated approximate expression, is 0.9988, which is sufficiently close to 1. Therefore, the above equation (1) was judged to be an appropriate approximation equation.

(Initial tensile strength)
Using the obtained ISO multipurpose test piece A type dumbbell (test piece), using a universal material testing machine 5969 (manufactured by Instron Co., Ltd.) according to ISO527-1 (2012 2nd edition), at 23 ° C. The initial tensile strength (MPa) was measured. The larger the value of the initial tensile strength, the higher the mechanical strength of the molded product (test piece).

(Tensile strength retention rate)
Using the obtained ISO multipurpose test piece A type dumbbell (test piece) and using a universal material testing machine 5969 (manufactured by Instron Co., Ltd.) according to ISO527-1 (2012 2nd edition), 23 ° C. The tensile strength was calculated from the following formula (2). This value was taken as the initial tensile strength (a).
Tensile strength (MPa) = breaking point stress (N) / cross-sectional area of test piece (mm ² ) (2)
Further, the test piece prepared by the same method as above is immersed in an aqueous solution obtained by diluting the antifreeze "Super Long Life Coolant" (pink) (manufactured by Toyota Motor Corporation) with water in a pressure resistant container, and the pressure resistance is increased. The container was allowed to stand for 2000 hours in a hot air dryer set at 130 ° C. After 2000 hours, a tensile test was performed on the test piece taken out from the hot air dryer by the same method as described above, and the tensile strength (b) of the test piece after the immersion test was measured.
The tensile strength retention rate was obtained from the following formula (3), and the tensile strength retention rate was evaluated.
Tensile strength retention rate (%) = {(b) / (a)} x 100 (3)
The larger the value of the tensile strength retention rate, the better the hydrolysis resistance.

(Number average molecular weight of semi-aromatic polyamide (a) in ISO multipurpose test piece A type dumbbell after durability test)
Using the obtained ISO multipurpose test piece A type dumbbell (test piece), immerse the antifreeze "Super Long Life Coolant" (pink) (manufactured by Toyota Motor Corporation) in an aqueous solution diluted 2-fold with water in a pressure-resistant container. The pressure-resistant container was allowed to stand in a hot air dryer set at 130 ° C. for 2000 hours. After 2000 hours, the number average molecular weight of the test piece taken out from the hot air dryer was measured by the same method as described above.

Production Example 1 [Production of Semi-Aromatic Polyamide A-1]
7586.2 g (45.7 mol) of terephthalic acid, 7374.2 g (46.7 mol), 7374.2 g (46.7 mol) of a mixture of 1,9-nonanedistillate and 2-methyl1,8-octanedistillate [80/20 (molar ratio)], benzoic acid Put 112.7 g (0.92 mol), 15 g of sodium hypophosphite monohydrate (0.1% by mass with respect to the total mass of the raw material) and 3.75 liters of distilled water in an autoclave with an internal volume of 40 liters. , Distilled with nitrogen. The internal temperature was raised to 220 ° C. over 3 hours. At this time, the autoclave was boosted to 2 MPa. After that, for 4 hours, the water vapor was gradually removed and the reaction was carried out while keeping the pressure at 2 MPa. Then, the pressure was reduced to 1.2 MPa over 30 minutes to obtain a prepolymer. The prepolymer was ground and dried at 120 ° C. under reduced pressure for 12 hours. This was subjected to solid phase polymerization under the conditions of 200 ° C. and 13.3 Pa for 2 hours, and then at 235 ° C. and 13.3 Pa to obtain a white semi-aromatic polyamide A-1. The melting point of A-1 was 300 ° C. The intrinsic viscosity was 1.14 dL / g, the terminal amino group amount ([NH ₂ ]) was 84 μe equivalent / g, and the terminal carboxy group amount ([COOH]) was 15 μe equivalent / g.

Production Example 2 [Production of Semi-Aromatic Polyamide A-2]
7586.2 g (45.7 mol) of terephthalic acid, a mixture of 1,9-nonandiamine and 2-methyl 1,8-octanedistillate [80/20 (molar ratio)] 7337.7 g (46.4 mol), benzoic acid Put 112.7 g (0.92 mol), 15 g of sodium hypophosphite monohydrate (0.1% by mass with respect to the total mass of the raw material) and 3.75 liters of distilled water in an autoclave with an internal volume of 40 liters. After that, a white semi-aromatic polyamide A-2 was obtained by the same method as in Production Example 1.
The melting point of A-2 is 300 ° C., the intrinsic viscosity is 1.16 dL / g, the terminal amino group amount ([NH ₂ ]) is 47 μe equivalent / g, and the terminal carboxy group amount ([COOH]) is 25 μe equivalent / g. rice field.

Production Example 3 [Production of Semi-Aromatic Polyamide A-3]
Terephthalic acid 7515.2 g (45.3 mol), mixture of 1,9-nonandiamine and 2-methyl 1,8-octanedistillate [80/20 (molar ratio)] 7360.9 g (46.6 mol), benzoic acid 196.8 g (1.61 mol), 15 g of sodium hypophosphite monohydrate (0.1% by mass with respect to the total mass of the raw material) and 3.75 liters of distilled water are placed in an autoclave with an internal volume of 40 liters. After that, a white semi-aromatic polyamide A-3 was obtained by the same method as in Production Example 1.
A-3 has a melting point of 300 ° C., an intrinsic viscosity of 1.04 dL / g, a terminal amino group amount ([NH ₂ ]) of 88 μe equivalent / g, and a terminal carboxy group amount ([COOH]) of 19 μe equivalent / g. rice field.

Production Example 4 [Production of Semi-Aromatic Polyamide A-4]
7562.5 g (45.6 mol) of terephthalic acid, a mixture of 1,9-nonandiamine and 2-methyl 1,8-octanedistillate [80/20 (molar ratio)] 7296.8 g (46.2 mol), benzoic acid 140.7 g (1.15 mol), 15 g of sodium hypophosphite monohydrate (0.1% by mass based on the total mass of the raw material) and 3.75 liters of distilled water are placed in an autoclave having an internal volume of 40 liters. After that, a white semi-aromatic polyamide A-4 was obtained by the same method as in Production Example 1.
A-4 has a melting point of 300 ° C., an intrinsic viscosity of 1.18 dL / g, a terminal amino group amount ([NH ₂ ]) of 9 μe equivalent / g, and a terminal carboxy group amount ([COOH]) of 34 μe equivalent / g. rice field.

Production Example 5 [Production of Semi-Aromatic Polyamide A-5]
7468.0 g (45.0 mol) of terephthalic acid, 7352.1 g (46.5 mol) of a mixture of 1,9-nonandiamine and 2-methyl 1,8-octanedistillate [80/20 (molar ratio)], benzoic acid 252.7 g (2.07 mol), 15 g of sodium hypophosphite monohydrate (0.1% by mass with respect to the total mass of the raw material) and 3.75 liters of distilled water are placed in an autoclave having an internal volume of 40 liters. After that, a white semi-aromatic polyamide A-5 was obtained by the same method as in Production Example 1.
The melting point of A-5 is 300 ° C., the intrinsic viscosity is 0.89 dL / g, the terminal amino group amount ([NH ₂ ]) is 95 μe equivalent / g, and the terminal carboxy group amount ([COOH]) is 26 μe equivalent / g. rice field.

Example 1 (Manufacturing of Polyamide Resin Composition)
The semi-aromatic polyamide (A), organic antioxidant (C), and other additives shown in Table 1 are premixed in the proportions shown in Table 1 to premix the twin-screw extruder "TEM-26SS" (Toshiba). While feeding from the upstream hopper of Machine Co., Ltd., the inorganic filler (B) was fed from the side feed port on the downstream side of the extruder so as to have the ratio shown in Table 1. Under the condition of a cylinder temperature of 320 ° C., the mixture was melt-kneaded, extruded, cooled and cut to produce a pellet-shaped polyamide resin composition. Using the pellet-shaped polyamide resin composition, an ISO multipurpose test piece A type dumbbell (test piece) for measuring each physical property was prepared by the above-mentioned method, and each physical property was measured by the above-mentioned method. The results are shown in Table 1.

Examples 2-5, Comparative Examples 1 and 2
A polyamide resin composition was produced in the same manner as in Example 1 except that the composition of the polyamide resin composition was changed as shown in Table 1, test pieces were prepared, and then the physical characteristics of each were measured. The results are shown in Table 1.

Each component shown in Table 1 is as follows.
<Inorganic filler (B)>
・ B-1: Glass fiber "CS03JA-FT2A" (manufactured by Owens Corning Japan GK)
・ B-2: Glass fiber "CS3J459" (manufactured by Nitto Boseki Co., Ltd.)
<Organic Antioxidant (C)>
・ C-1: "Smilizer GA-80" (manufactured by Sumitomo Chemical Co., Ltd.)
・ C-2: "Irganox1098" (manufactured by BASF Japan Ltd.)
・ C-3: "Naugard 445" (manufactured by Adiband Japan Co., Ltd.)

<Other additives>
-Crystal nucleating agent: "TALC ML112" (manufactured by Fuji Talc Co., Ltd.)
-Colorant: Carbon black "# 980B" (manufactured by Mitsubishi Chemical Corporation)
-Release agent: "Licowax OP" (manufactured by Clariant Japan Co., Ltd.)

As shown in Table 1, the molded product of the polyamide resin composition of the present invention is suppressed from decreasing in number average molecular weight even when it is in contact with a high temperature long life coolant (LLC aqueous solution) for a long time, and as a result, the tensile strength retention rate is suppressed. It can be seen that the temperature is high and the hydrolysis resistance is excellent. Further, it can be seen that the molded product of the polyamide resin composition of the present invention has both high hydrolysis resistance and high mechanical strength.

Claims (11)

A polyamide resin composition containing 10 to 200 parts by mass of the inorganic filler (B) with respect to 100 parts by mass of the semi-aromatic polyamide (A).
When the amount of terminal amino groups in the molecular chain of the semi-aromatic polyamide (A) is expressed as [NH ₂ ] (μ equivalent / g) and the amount of terminal carboxy groups is expressed as [COOH] (μ equivalent / g). Satisfy the following formula (I) and
A polyamide resin having a number average molecular weight of 5500 or more of the semi-aromatic polyamide (a) in an ISO multipurpose test piece A type dumbbell obtained by injection molding the polyamide resin composition under the conditions of a cylinder temperature of 320 ° C. and a mold temperature of 140 ° C. Composition.
1 ≦ [NH ₂ ] / [COOH] <6 (I) The polyamide resin composition according to claim 1, which contains 0.01 to 5 parts by mass of the organic antioxidant (C) with respect to 100 parts by mass of the semi-aromatic polyamide (A). The polyamide resin composition according to claim 1 or 2, wherein the content of the copper compound is less than 1 part by mass with respect to 100 parts by mass of the semi-aromatic polyamide (A). The polyamide resin composition according to any one of claims 1 to 3, wherein the content of the copper compound is less than 0.01 parts by mass with respect to 100 parts by mass of the semi-aromatic polyamide (A). The semi-aromatic polyamide (A) contains a dicarboxylic acid unit and a diamine unit, and contains.
50 to 100 mol% of the dicarboxylic acid unit is a structural unit derived from at least one selected from terephthalic acid or naphthalenedicarboxylic acid, and 60 to 100 mol% of the diamine unit is an aliphatic diamine having 6 to 10 carbon atoms. The polyamide resin composition according to any one of claims 1 to 4, which is a structural unit derived from. The polyamide resin composition according to claim 5, wherein the aliphatic diamine is at least one selected from 1,10-decanediamine, 1,9-nonanediamine and 2-methyl-1,8-octanediamine. The polyamide resin composition according to claim 5 or 6, wherein the aliphatic diamine is 1,9-nonanediamine and 2-methyl-1,8-octanediamine. The polyamide resin composition according to claim 7, wherein the molar ratio of 1,9-nonamethylenediamine to 2-methyl-1,8-octamethylenediamine is 99: 1 to 40:60. The polyamide resin composition according to any one of claims 1 to 8, wherein the inorganic filler (B) is at least one selected from glass fibers and carbon fibers. A molded product of the polyamide resin composition according to any one of claims 1 to 9. The molded product of the polyamide resin composition according to claim 10, which is a component that comes into contact with a long-life coolant.