Polyamide resins, polyamide resin compositions, and molded articles

Abstract

To provide a polyamide resin having improved moldability and durability while maintaining heat resistance, a polyamide resin composition, and a molding.SOLUTION: A polyamide resin comprises a polymer block (A) comprising 50 mol% or more of a constitutional unit derived from polyamide, and a chain extender (B). In the polyamide resin, the content of the polymer block (A) is 91.0 mass% or more and less than 99.0 mass%. The polyamide resin has a weight average molecular weight of 40,000-150,000.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to polyamide resins, polyamide resin compositions, and molded articles. [Background technology]

[0002] To reduce fuel consumption in internal combustion engine vehicles and extend the driving range of electric vehicles, there is a demand for lighter vehicles, and replacing metal parts with resin parts is an effective solution. Various polyamides with excellent heat resistance, durability, and chemical resistance have been proposed as metal substitutes, but currently they are not suitable for applications requiring extremely high durability. Conventionally, it has been known that increasing the molecular weight of a resin is effective in improving durability such as fatigue resistance, creep resistance, and wear resistance (see, for example, Non-Patent Documents 1-3). However, using high molecular weight resins increases the melt viscosity of the resin, so there is an upper limit to the molecular weight while ensuring moldability. Therefore, when replacing metal parts with resin parts, there is a problem of insufficient durability when trying to ensure moldability. It is known that using chain extenders can suppress the increase in resin melt viscosity as a method to increase the molecular weight of polyamides (see Patent Documents 1-4). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Special Publication No. 2003-520877 [Patent Document 2] Special Publication No. 2017-511420 [Patent Document 3] Special Publication No. 2001-521576 [Patent Document 4] Japanese Patent Application Publication No. 06-211986 [Non-patent literature]

[0004] [Non-Patent Document 1] Polymer Life Prediction and Life Extension Technologies, published October 1, 2002, Publisher: NTS Co., Ltd., authored by Zenjiro Osawa et al., pp. 166-183. [Non-Patent Document 2] Journal of Materials Science,23(10),3648-3655,1988 [Non-Patent Document 3] TOSOH Research&Technology Review, Vol.44, 64 pages, 2000 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, the manufacturing method described in Patent Document 1, in which a chain extender is mixed during the polymerization stage of polyamide, has the problem that the inherent properties of the polyamide cannot be obtained. Furthermore, the high molecular weight polyamide obtained by the method described in Patent Document 2, which involves compounding a chain extender with a polyamide precursor and obtaining it by melt kneading, has properties other than melt viscosity that are unknown. Furthermore, the method for melt polymerization of a relatively low molecular weight polyamide and bislactam described in Patent Document 3 does not specify the molecular weight of the resulting high molecular weight product. Furthermore, while Patent Document 4 discloses a method for the addition reaction between an oligomer having a dicarboxyl terminus and bisoxazoline, it does not describe a relatively low molecular weight oligomer, but does not describe a high molecular weight oligomer. Furthermore, while Non-Patent Documents 1-3 describe the relationship between the molecular weight and durability of resins, these only discuss simple resin structures and do not provide specific disclosures or suggestions regarding resins obtained with chain extenders.

[0006] Therefore, there is a demand for polyamide-based resins that possess not only the excellent heat resistance of polyamides, but also moldability and durability such as fatigue resistance. Therefore, the object of the present invention is to provide a polyamide resin, a polyamide resin composition, and a molded article that maintain heat resistance while improving moldability and durability. [Means for solving the problem]

[0007] As a result of diligent consideration in order to solve the above problems, the inventors have come up with the following invention and found that it can solve the problems. In other words, the present invention is as follows. A polyamide resin comprising a polymer block (A) containing 50 mol% or more of polyamide-derived structural units and a chain extender (B), The content of polymer blocks (A) in the polyamide resin is 91.0% by mass or more and less than 99.0% by mass. A polyamide resin having a weight-average molecular weight of 40,000 to 150,000. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide polyamide resins, polyamide resin compositions, and molded articles that maintain heat resistance while improving moldability and durability (fatigue resistance). [Modes for carrying out the invention]

[0009] The following description will be based on an example of an embodiment of the present invention. However, the embodiments shown below are illustrative examples for embodying the technical concept of the present invention, and the present invention is not limited to the following description. Furthermore, while preferred embodiments are shown in this specification, combinations of two or more individual preferred embodiments are also preferred embodiments. If there are several numerical ranges for an item indicated by a numerical range, a preferred embodiment can be created by selectively combining the lower and upper limits of those ranges. In this specification, when a numerical range such as "XX~YY" is mentioned, it means "XX or greater and YY or less."

[0010] [Polyamide resin] The polyamide-based resin of the present embodiment is a polyamide-based resin containing a polymer block (A) containing 50 mol% or more of structural units derived from polyamide and a chain extender (B), wherein the content of the polymer block (A) in the polyamide-based resin is 91.0% by mass or more and less than 99.0% by mass, and the weight average molecular weight of the polyamide-based resin is 40,000 to 150,000.

[0011] The polyamide-based resin of the present embodiment contains polyamide as the polymer block (A) and is a polymer obtained by reacting with a chain extender (B). By having a specific weight average molecular weight, the polyamide-based resin of the present embodiment can maintain the excellent heat resistance of polyamide, have good moldability (molding processability), and exhibit excellent durability (fatigue resistance).

[0012] <Polymer block (A)> The polymer block (A) contains 50 mol% or more of structural units derived from polyamide. From the viewpoint of more easily obtaining more excellent heat resistance, the polymer block (A) preferably contains 70 mol% or more, more preferably 90 mol% or more, and can also contain 100 mol% of structural units derived from polyamide. In the polymer block (A), the structural units other than the structural units derived from polyamide are not limited as long as the effects of the present invention can be obtained. The polyamide that can be used in the present embodiment is not limited as long as the effects of the present invention can be obtained, and examples thereof include semi-aromatic polyamide, wholly aromatic polyamide, and aliphatic polyamide. Among them, semi-aromatic polyamide and aliphatic polyamide are mentioned as polyamides in which the effects of the present invention are more显著. From the viewpoint of more easily obtaining more excellent heat resistance, it is particularly preferable to use semi-aromatic polyamide as the polyamide. Examples of the aliphatic polyamide include polytetramethylene adipamide (polyamide 46) and polyhexamethylene adipamide (polyamide 66). Semi-aromatic polyamides that can be suitably used in this embodiment are described in detail below.

[0013] <<Semi-aromatic polyamide>> Semi-aromatic polyamide refers to a polyamide containing diamine units mainly composed of aliphatic diamine units and dicarboxylic acid units mainly composed of aromatic dicarboxylic acid units, or a polyamide resin containing dicarboxylic acid units mainly composed of aliphatic dicarboxylic acid units and diamine units mainly composed of aromatic diamine units. Here, "main component" means that it constitutes 50 to 100 mol%, preferably 60 to 100 mol%, of the total units. In this embodiment, the semi-aromatic polyamide is preferably composed of diamine units mainly consisting of aliphatic diamine units and dicarboxylic acid units mainly consisting of aromatic dicarboxylic acid units, from the viewpoint of having superior heat resistance.

[0014] (Aliphatic diamine units) Semi-aromatic polyamides preferably contain 30 mol% or more of diamine units derived from aliphatic diamines having 4 to 18 carbon atoms, relative to the total diamine units, from the viewpoint that polymerization reactions with dicarboxylic acids proceed well and are advantageous in improving physical properties such as heat resistance and durability (fatigue resistance). More preferably, 30 to 100 mol%, even more preferably 50 to 100 mol%, even more preferably 70 to 100 mol%, even more preferably 90 to 100 mol%, and may contain 100 mol%. Furthermore, as the aliphatic diamine used in the above-mentioned diamine unit, an aliphatic diamine having 4 to 16 carbon atoms is more preferred, an aliphatic diamine having 4 to 12 carbon atoms is even more preferred, an aliphatic diamine having 6 to 12 carbon atoms is even more preferred, and an aliphatic diamine having 6 to 10 carbon atoms is even more preferred.

[0015] Examples of aliphatic diamines having 4 to 18 carbon atoms include linear aliphatic diamines such as 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,13-tridecanediamine, 1,14-tetradecanediamine, 1,15-pentadecanediamine, 1,16-hexadecanediamine, 1,17-heptadecanediamine, and 1,18-octadecanediamine; 1-Butyl-1,2-ethanediamine, 1,1-dimethyl-1,4-butanediamine, 1-ethyl-1,4-butanediamine, 2-ethyl-1,4-butanediamine, 1,2-dimethyl-1,4-butanediamine, 1,3-dimethyl-1,4-butanediamine, 1,4-dimethyl-1,4-butanediamine, 2-methyl-1,3-propanediamine, 2-methyl-1,4-butanediamine, 2,3-dimethyl-1,4-butanediamine, 2-methyl-1, 5-pentanediamine, 3-methyl-1,5-pentanediamine, 2-ethyl-1,5-pentanediamine, 2-propyl-1,5-pentanediamine, 2-butyl-2-ethyl-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 Min, 2,4,4-trimethyl-1,6-hexanediamine, 2-ethyl-1,6-hexanediamine, 2-propyl-1,6-hexanediamine, 2,4-diethyl-1,6-hexanediamine, 2-ethyl-1,7-heptanediamine, 2-propyl-1,7-heptanediamine, 2-methyl-1,8-octanediamine, 3-methyl-1,8-octanediamine, 1,3-dimethyl-1,8-octanediamine, 1,4-dimethyl-1,8-octanediamine Branched aliphatic diamines such as 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-octanediamine, 2-ethyl-1,8-octanediamine, 2-methyl-1,9-nonanediamine, and 5-methyl-1,9-nonanediamine; Examples include alicyclic diamines such as 1,2-cyclohexanediamine, 1,4-cyclohexanediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, and bis(aminopropyl)piperazine. These may be used individually or in combination of two or more. From the viewpoint of heat resistance, it is preferable to use at least one aliphatic diamine selected from the group consisting of linear aliphatic diamines and branched aliphatic diamines, and it is more preferable to use linear aliphatic diamines and branched aliphatic diamines in combination.

[0016] From the viewpoint of more pronounced effects of the present invention and excellent raw material availability, the semi-aromatic polyamide preferably contains a diamine unit derived from at least one selected from the group consisting of 1,4-butanediamine, 1,6-hexanediamine, 1,9-nonanediamine, 2-propyl-1,6-hexanediamine, 2-ethyl-1,7-heptanediamine, 2-methyl-1,8-octanediamine, 1,10-decanediamine, 1,11-undecanediamine, and 1,12-dodecanediamine, more preferably contains a diamine unit derived from at least one selected from the group consisting of 1,9-nonanediamine and 2-methyl-1,8-octanediamine, and from the viewpoint of moldability, it is even more preferable to use both 1,9-nonanediamine and 2-methyl-1,8-octanediamine in combination. The content of 1,9-nonanediamine units and / or 2-methyl-1,8-octanediamine units in the total amount of diamine units constituting the semi-aromatic polyamide is preferably 50 to 100 mol%, more preferably 60 to 100 mol%, even more preferably 75 to 100 mol%, and even more preferably 90 to 100 mol%. When the content of 1,9-nonanediamine units and / or 2-methyl-1,8-octanediamine units in the total amount of diamine units constituting the semi-aromatic polyamide is within the above range, heat resistance is further improved, and excellent chemical resistance can also be expected.

[0017] When 1,9-nonanediamine and 2-methyl-1,8-octanediamine are used in combination, the molar ratio of 1,9-nonanediamine to 2-methyl-1,8-octanediamine is preferably 99:1 to 1:99, more preferably 95:5 to 5:95, and even more preferably 90:10 to 10:90. When the molar ratio of 1,9-nonanediamine and 2-methyl-1,8-octanediamine is within the above range, the reaction with the chain extender (B) proceeds well, and excellent heat resistance and durability (fatigue resistance) can be expected in the resulting polyamide resin.

[0018] Furthermore, the semi-aromatic polyamide may contain constituent units derived from aliphatic diamines other than aromatic diamines, as long as the effects of the present invention are not impaired. These constituent units derived from aliphatic diamines may consist of only one type or two or more types. The content of constituent units other than the above-mentioned aliphatic diamine in the diamine unit is preferably 30 mol% or less, more preferably 20 mol% or less, even more preferably 10 mol% or less, and even more preferably 5 mol% or less.

[0019] (Aromatic dicarboxylic acid unit) Examples of aromatic dicarboxylic acid units include those derived from isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenic acid, 4,4'-biphenyldicarboxylic acid, diphenylmethane-4,4'-dicarboxylic acid, and diphenylsulfone-4,4'-dicarboxylic acid, from the viewpoint that they undergo polymerization reactions with diamines well and are advantageous for improving physical properties such as heat resistance. From the viewpoint of more significantly exhibiting the effects of the present invention, the semi-aromatic polyamide preferably contains dicarboxylic acid units derived from at least one selected from the group consisting of terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid, and from the viewpoint of further improving heat resistance, it is more preferable that it contains dicarboxylic acid units derived from at least one selected from the group consisting of terephthalic acid and 2,6-naphthalenedicarboxylic acid. These aromatic dicarboxylic acid units may be used individually or in combination of two or more.

[0020] From the viewpoint of heat resistance and mechanical strength, semi-aromatic polyamides preferably contain 30 mol% or more of dicarboxylic acid units derived from at least one selected from the group consisting of terephthalic acid and 2,6-naphthalenedicarboxylic acid, more preferably 30 to 100 mol%, even more preferably 50 to 100 mol%, even more preferably 70 to 100 mol%, even more preferably 90 to 100 mol%, and may contain 100 mol%.

[0021] Furthermore, the semi-aromatic polyamide may contain constituent units other than aromatic dicarboxylic acids, such as aliphatic dicarboxylic acids, as dicarboxylic acid units, provided that the effects of the present invention are not impaired. These constituent units other than aromatic dicarboxylic acids may consist of only one type or two or more types. Examples of aliphatic dicarboxylic acids include linear aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, and dimethylmalonic acid; Branched aliphatic dicarboxylic acids such as 2,2-diethylsuccinic acid, 2,2-dimethylglutaric acid, 2-methyladipic acid, and trimethyladipic acid; Examples include alicyclic dicarboxylic acids such as 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid; and so on. The content of constituent units other than the above-mentioned aromatic dicarboxylic acid in the dicarboxylic acid unit is preferably 30 mol% or less, more preferably 20 mol% or less, even more preferably 10 mol% or less, and even more preferably 5 mol% or less.

[0022] The content of units derived from the above-mentioned aliphatic diamine having 4 to 18 carbon atoms relative to the total constituent units of the semi-aromatic polyamide is preferably 25 to 55 mol%, and more preferably 35 to 55 mol%. The content of units derived from aromatic dicarboxylic acids relative to the total constituent units of the semi-aromatic polyamide is preferably 15 to 55 mol%, and more preferably 25 to 55 mol%. The total content of units derived from the above-mentioned aliphatic diamines and aromatic dicarboxylic acids having 4 to 18 carbon atoms, relative to all constituent units of the semi-aromatic polyamide, is preferably 40 to 100 mol%, more preferably 60 to 100 mol%, even more preferably 70 to 100 mol%, and may be 90 mol% or more, or even 100 mol%.

[0023] (Other units) Furthermore, the semi-aromatic polyamide may contain other units besides diamine units and dicarboxylic acid units, as long as they do not impair the effects of the present invention. Examples of other units include polycarboxylic acid units, aminocarboxylic acid units, and lactam units. Examples of polycarboxylic acid units include constituent units derived from polycarboxylic acids with a valency of three or more, such as trimellitic acid, trimesic acid, and pyromellitic acid. These polycarboxylic acid units can be included to the extent that melt molding is possible. Examples of aminocarboxylic acid units include lactams such as caprolactam and lauryllactam; and constituent units derived from aminocarboxylic acids such as 11-aminoundecanoic acid and 12-aminododecanoic acid. Examples of lactam units include constituent units derived from ε-caprolactam, enantractam, undecanlactam, lauryllactam, α-pyrrolidone, α-piperidone, and others. The content of other units relative to the total constituent units of the semi-aromatic polyamide is preferably 30 mol% or less, and more preferably 10 mol% or less.

[0024] Representative semi-aromatic polyamides containing diamine units mainly composed of aliphatic diamine units and dicarboxylic acid units mainly composed of aromatic dicarboxylic acid units include polytetramethylene terephthalamide (Polyamide 4T), polypentamethylene terephthalamide (Polyamide 5T), polyhexamethylene terephthalamide (Polyamide 6T), polynonameethylene terephthalamide (Polyamide 9T), poly(2-methyloctamethylene) terephthalamide (Polyamide M8T), polynonameethylene terephthalamide / poly(2-methyloctamethylene) terephthalamide copolymer (Polyamide 9T / M8T), polynonameethylene naphthalenedicarboxamide (Polyamide 9N), poly(2-methyloctamethylene) naphthalenedicarboxamide (Polyamide M8N), and Examples include linonamethylene naphthalenedicarboxamide / poly(2-methyloctamethylene)naphthalenedicarboxamide copolymer (polyamide 9N / M8N), polydecamethylene terephthalamide (polyamide 10T), polyhexamethylene isophthalamide (polyamide 6I), copolymer of polyamide 6I and polyamide 6T (polyamide 6I / 6T), copolymer of polyamide 66, polyamide 6I and polyamide 6T (polyamide 66 / polyamide 6I / 6T), copolymer of polyamide 6T and polyundecaneamide (polyamide 11) (polyamide 6T / 11), copolymer of polyamide 6T and polyamide 10T (polyamide 6T / 10T), and copolymer of polyamide 10T and polyundecaneamide (polyamide 11) (polyamide 10T / 11).

[0025] <<End-Capping Agent>> In this embodiment, the polyamide contained in the polymer block (A) may include constituent units derived from the end-capturing agent. The units derived from the end-capturing agent are preferably 1.0 to 10 mol%, more preferably 2.0 to 7.5 mol%, and even more preferably 2.5 to 6.5 mol% relative to the diamine units. The number of units derived from the end encapsulant can be set to the desired range by adding the end encapsulant to the diamine during the preparation of the polymerization raw materials in the desired manner. It is desirable to fine-tune the amount of end encapsulant added during the preparation of the polymerization raw materials so that the desired amount of units derived from the end encapsulant is introduced into the resulting resin, taking into account the volatilization of monomer components during polymerization. Furthermore, the end encapsulant can also be added to the polymer constituting the polymer block (A) along with the end functionalizer described later, in the desired manner. Additionally, the end encapsulant can be added to the polymer constituting the polymer block (A) during the chain extension reaction with the chain extender described later, in the desired manner.

[0026] One method for determining the content of units derived from end-captive agents in polyamide is, for example, as shown in Japanese Patent Publication No. 07-228690, to measure the solution viscosity, calculate the total amount of end-captive groups from the relationship between the viscosity and the number-average molecular weight, and then subtract the amount of amino groups and carboxyl groups determined by titration. As end-capping agents, monofunctional compounds that react with terminal amino groups or terminal carboxyl groups can be used. Specifically, examples include monocarboxylic acids, acid anhydrides, monoisocyanates, monoacid halides, monoesters, monoalcohols, and monoamines. From the viewpoint of reactivity and stability of the encapsulated end, monocarboxylic acids are preferred as end-capping agents for terminal amino groups, and monoamines are preferred as end-capping agents for terminal carboxyl groups. From the viewpoint of ease of handling, monocarboxylic acids are more preferred as end-capping agents.

[0027] There are no particular restrictions on the monocarboxylic acid used as a terminal encapsulant, as long as it is reactive with an amino group. Examples of monocarboxylic acids include aliphatic monocarboxylic acids such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, and isobutyric acid; alicyclic monocarboxylic acids such as cyclopentaneic acid and cyclohexanecarboxylic acid; aromatic monocarboxylic acids such as benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, and phenylacetic acid; and any mixture thereof. Among these, at least one selected from acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, and benzoic acid is preferred in terms of reactivity, stability of the encapsulated end, and cost.

[0028] There are no particular restrictions on the monoamine used as a terminal encapsulant, as long as it is reactive with a carboxyl group. Examples of monoamines include aliphatic monoamines such as methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine, and dibutylamine; alicyclic monoamines such as cyclohexylamine and dicyclohexylamine; aromatic monoamines such as aniline, toluidine, diphenylamine, and naphthylamine; and any mixture thereof. Among these, at least one selected from butylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine, and aniline is preferred in terms of reactivity, high boiling point, stability of the encapsulated end, and cost.

[0029] <<Method for producing polyamide>> When the polyamide is a semi-aromatic polyamide containing dicarboxylic acid units and diamine units, the above-mentioned semi-aromatic polyamide can be produced, for example, using dicarboxylic acid and diamine as raw materials by methods such as melt polymerization, solid-phase polymerization, and melt extrusion polymerization. Specifically, the semi-aromatic polyamide can be produced as follows. First, a nylon salt is produced by mixing a diamine, a dicarboxylic acid, and optionally an aminocarboxylic acid, lactam, a catalyst, an end-capturing agent, etc. Next, the produced nylon salt is heated to a temperature of 200-250°C and subjected to thermal polymerization to obtain a semi-aromatic polyamide as a prepolymer. Furthermore, the semi-aromatic polyamide can be adjusted to the desired molecular weight by solid-phase polymerization of the prepolymer or by increasing the degree of polymerization using a melt extruder. When the high polymerization stage is carried out by solid-phase polymerization, it is preferable to do so under reduced pressure or inert gas flow. If the polymerization temperature is within the range of 200 to 280°C, the polymerization rate is high, productivity is excellent, and discoloration and gelation can be effectively suppressed. Furthermore, when the high polymerization stage is carried out by a melt extruder, the polymerization temperature is preferably 370°C or lower. When polymerization is carried out under these conditions, a semi-aromatic polyamide with almost no decomposition and little degradation is obtained.

[0030] Examples of catalysts that can be used in the production of semi-aromatic polyamides include phosphoric acid, phosphorous acid, hypophosphorous acid, or salts or esters thereof. Examples of the salts or esters include salts of phosphoric acid, phosphorous acid, or hypophosphorous acid with metals such as potassium, sodium, magnesium, vanadium, calcium, zinc, cobalt, manganese, tin, tungsten, germanium, titanium, and antimony; ammonium salts of phosphoric acid, phosphorous acid, or hypophosphorous acid; and ethyl esters, isopropyl esters, butyl esters, hexyl esters, isodecyl esters, octadecyl esters, decyl esters, stearyl esters, and phenyl esters of phosphoric acid, phosphorous acid, or hypophosphorous acid. The amount of catalyst used is preferably 0.01% by mass or more, and more preferably 0.05% by mass or more, based on 100% by mass of the total mass of the semi-aromatic polyamide raw materials. Furthermore, the amount of catalyst used is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less. Polymerization proceeds more smoothly when the amount of catalyst used is above the above lower limit.

[0031] <<Terminal amino group content (before terminal transformation)>> In this embodiment, the ends of the polyamide can be adjusted to a desired functional group or amount of functional group using a terminal functionalizing agent described later. On the other hand, the terminal amino group content referred to here is the terminal amino group content of the polyamide before terminal transformation by a terminal functionalizing agent. The polyamide before the above-mentioned terminal conversion has a terminal amino group content ([NH2]) of preferably 1 to 50 μmol / g, more preferably 1 to 40 μmol / g, even more preferably 1 to 30 μmol / g, and even more preferably 1 to 20 μmol / g. In this specification, terminal amino group content ([NH2]) refers to the amount of terminal amino groups (in μmol) contained in 1 g of polyamide, and can be determined by a neutralization titration method using an indicator.

[0032] <<Terminal carboxyl group content (before terminal transformation)>> The polyamide before the above-mentioned terminal conversion has a terminal carboxyl group content ([COOH]) of preferably 50 to 600 μmol / g, more preferably 60 to 600 μmol / g, even more preferably 70 to 600 μmol / g, and even more preferably 75 to 600 μmol / g. In this specification, terminal carboxyl group content ([COOH]) refers to the amount of terminal carboxyl groups (in μmol) contained in 1 g of polyamide, and can be determined by potentiometric titration.

[0033] <<Melting point>> The melting point of the polyamide is preferably 230°C or higher, more preferably 240°C or higher, and even more preferably 250°C or higher. There is no particular upper limit to the melting point of the polyamide, but from the viewpoint of moldability and other factors, it is preferable that it be 320°C or lower. If the melting point of the polyamide is 230°C or higher, the heat resistance of the polyamide resin in this embodiment can be further improved. In the present invention, the melting point can be determined using a differential scanning calorimetry (DSC) apparatus as the peak temperature of the melting peak that appears when the temperature is increased at a rate of 10°C / min. More specifically, it can be determined by the method described in the examples below.

[0034] <<Molecular weight>> The number-average molecular weight of the polymer block (A) is preferably 2,000 to 10,000, more preferably 2,200 to 10,000, even more preferably 2,400 to 8,000, and even more preferably 2,500 to 7,000. Within the above numerical range, the reactivity between the polymer block (A) and the chain extender (B) is excellent, and the heat resistance, moldability (processability), and durability (fatigue resistance) of the polyamide resin can be further improved. The weight-average molecular weight of the polymer block (A) is preferably 8,000 to 50,000, more preferably 9,000 to 45,000, even more preferably 10,000 to 40,000, even more preferably 10,000 to 35,000, and even more preferably 10,000 to 30,000. Within the above numerical range, the reactivity between the polymer block (A) and the chain extender (B) is excellent, and the heat resistance, moldability (processability), and durability (fatigue resistance) of the polyamide resin can be further improved. In the present invention, the number-average molecular weight and the weight-average molecular weight can be measured by gel permeation chromatography, and more specifically, by the method described in the examples.

[0035] <<End-level functionalizing agent>> In this embodiment, a terminal functionalizing agent can be used to obtain a polymer block (A) in which the ends of the polyamide are adjusted to a desired functional group or amount of functional group. For example, the ends of a polyamide can be transformed by reacting the aforementioned polyamide prepolymer with a terminal functionalizing agent. By adjusting the ends of polymer block (A) to the desired functional group or amount of functional group, polymer block (A) and chain extender (B) can be bonded more effectively. Units derived from the terminal functionalizing agent are included in polymer block (A).

[0036] Furthermore, if the polyamide obtained by the above-described method for producing polyamide has the desired functional groups or amount of functional groups, it is not necessary to use a terminal functionalizing agent. In other words, in this case, a polyamide resin in which the polymer block (A) and the chain extender (B) are well bonded can be obtained by reacting the polyamide with the chain extender (B) without using a terminal functionalizing agent. Furthermore, the adjustment of the amount of active terminal functional groups in polyamides, as described later, can be done, for example, by adjusting the amount of carboxyl groups and amino groups contained in the reaction raw materials during the production of polyamides. When using a terminal functionalizing agent, the terminal functionalizing agent can be added during polymerization of the polymer constituting polymer block (A) to adjust the polyamide terminals to the desired functional group or amount of functional group. Alternatively, the terminal functionalizing agent can be added to the polymer constituting polymer block (A) along with a terminal encapsulant to adjust the polyamide terminals to the desired functional group or amount of functional group. Furthermore, the terminal functionalizing agent can be added during the chain extension reaction between the polymer constituting polymer block (A) and the chain extender described later to adjust the polyamide terminals to the desired functional group or amount of functional group.

[0037] The terminal functionalizing agent is not limited as long as it does not impair the effects of the present invention, and can be used to introduce functional groups such as hydroxyl groups, carboxyl groups, amino groups, epoxy groups, mercapto groups, sulfonyl groups, halogen atoms, vinyl groups, and vinylidene groups to the ends of the polyamide.

[0038] In this embodiment, it is preferable to use dicarboxylic acids and diamines as terminal functionalizers. Examples of dicarboxylic acids that can be used as terminal functionalizing agents include aliphatic dicarboxylic acids and aromatic dicarboxylic acids. Examples of aliphatic dicarboxylic acids include linear aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, and dimethylmalonic acid; Branched aliphatic dicarboxylic acids such as 2,2-diethylsuccinic acid, 2,2-dimethylglutaric acid, 2-methyladipic acid, and trimethyladipic acid; Examples include alicyclic dicarboxylic acids such as 1,3-cyclopentanedicarboxylic acid and 1,4-cyclohexanedicarboxylic acid; and so on. Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, diphenic acid, 4,4'-biphenyldicarboxylic acid, diphenylmethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 2,3-frandicarboxylic acid, 2,4-frandicarboxylic acid, 2,5-frandicarboxylic acid, and 3,4-frandicarboxylic acid.

[0039] Examples of diamines that can be used as terminal functionalizing agents include aliphatic diamines and aromatic diamines. Examples of aliphatic diamines include linear aliphatic diamines such as ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, 1,13-tridecanediamine, 1,14-tetradecanediamine, 1,15-pentadecanediamine, 1,16-hexadecanediamine, 1,17-heptadecanediamine, and 1,18-octadecanediamine; 1,2-propanediamine, 1-butyl-1,2-ethanediamine, 1,1-dimethyl-1,4-butanediamine, 1-ethyl-1,4-butanediamine, 2-ethyl-1,4-butanediamine, 1,2-dimethyl-1,4-butanediamine, 1,3-dimethyl-1,4-butanediamine, 1,4-dimethyl-1,4-butanediamine, 2-methyl-1,3-propanediamine, 2-methyl-1,4-butanediamine, 2,3-dimethyl-1,4-butanediamine 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 2-ethyl-1,5-pentanediamine, 2-propyl-1,5-pentanediamine, 2-butyl-2-ethyl-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-ethyl-1,6-hexanediamine, 2-propyl-1,6-hexanediamine, 2,4-diethyl-1,6-hexanediamine, 2-ethyl-1,7-heptanediamine, 2-propyl-1,7-heptanediamine, 2-methyl-1,8-octanediamine, 3-methyl-1,8-octanediamine, 1,3-dimethyl-1,8-octanediamine, 1,4-dimethyl-1,8- Branched aliphatic diamines such as 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-octanediamine, 2-ethyl-1,8-octanediamine, 2-methyl-1,9-nonanediamine, and 5-methyl-1,9-nonanediamine; Examples include alicyclic diamines such as 1,2-cyclohexanediamine, 1,4-cyclohexanediamine, 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane, bis(4-aminocyclohexyl)methane, bis(3-methyl-4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, and bis(aminopropyl)piperazine. Examples of aromatic diamines include p-phenylenediamine, m-phenylenediamine, p-xylylenediamine, m-xylylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenyl ether, and 4,4'-methylenedi-2,6-diethylaniline. The above-mentioned terminal functionalizing agents may consist of only one type or two or more types.

[0040] <<Active terminal functional group content>> In the present invention, "active end functional group content" refers to the content of active end functional groups in the polymer block (A) contained in the polyamide resin, and the total content of active end functional groups in the polyamide is the active end functional group content of the polymer block (A). "Active end functional group" refers to a functional group that exhibits reactive activity with respect to the chain extender (B), and examples include amino groups and carboxyl groups. When the ends of a polyamide are converted using a terminal functionalizing agent, the "active terminal functional group content" refers to the content of the active terminal functional groups after the conversion. For example, when a polyamide having amino groups at its ends is converted to carboxyl groups using a terminal functionalizing agent, the total content of the converted terminal carboxyl groups and the unconverted terminal amino groups becomes the active terminal functional group content of polymer block (A).

[0041] The active end functional group content of polymer block (A) is preferably 75 to 600 μmol / g, more preferably 90 to 560 μmol / g, and even more preferably 100 to 520 μmol / g. If the active end functional group content is 75 μmol / g or more, the reactivity between polymer block (A) and chain extender (B) is excellent, and the moldability (processability) and durability (fatigue resistance) of the polyamide resin can be further improved. Furthermore, if the active end functional group content is 600 μmol / g or less, the heat resistance of the polyamide resin can be further improved. In this specification, the active end functional group content refers to the amount of active end functional groups (in μmol) contained in 1 g of polyamide (or the converted polyamide if an end functionalizing agent is used), and can be determined by neutralization titration using an indicator and potentiometric titration. Specifically, it can be calculated by the method described in the examples below.

[0042] The content of polymer blocks (A) in the polyamide resin is not particularly limited as long as it is 91.0% by mass or more and less than 99.0% by mass. However, from the viewpoint of maintaining the heat resistance of the resulting polyamide resin while providing moldability and excellent fatigue resistance, it is preferably 92.0% by mass or more and 98.7% by mass or less, more preferably 93.5% by mass or more and 98.5% by mass or less, and even more preferably 95.0% by mass or more and 98.3% by mass or less.

[0043] <Chain extender (B)> In this embodiment, the chain extender (B) is a compound having two groups that react with the active terminal functional groups of the polymer block (A), specifically terminal amino groups or terminal carboxyl groups, and can be represented, for example, as Y1-A'-Y1. Examples of Y1 include maleimide groups, isocyanate groups, oxazinon groups, oxazolinone groups, cyclic anhydride groups, caprolactam groups, oxazolyl groups, oxazine groups, imidazoline groups, aziridine groups, or epoxy groups. A' may be an alkylene group, a cycloalkylene group, an arylene group, or a single covalent bond between two Y1 groups. Such alkylene groups, cycloalkylene groups, or arylene groups may have substituents.

[0044] Examples of chain extenders (B) in which Y1 is a cyclic anhydride group include ethylenetetracarboxylic acid dianhydride, pyromellitic acid dianhydride, 3,3',4,4'-biphenyltetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic acid dianhydride, perylenetetracarboxylic acid dianhydride, 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride, 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, hexafluoroisopropylidenebisphthalic acid dianhydride, 9,9-bis(trifluoromethyl)xanthentetracarboxylic acid dianhydride, 3,3',4,4'-diphenylsulfonetetracarboxylic acid dianhydride, bicyclo[2.2.2]octa-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, 1,2,3,4-cyclopentanetetracarboxylic acid dianhydride, and 3,3',4,4'-diphenylethertetracarboxylic acid dianhydride.

[0045] Examples of chain extenders (B) having an epoxy group in Y1 include bisphenol A diglycidyl ether (DGEBA) and its (alicyclic) hydrogenated derivatives, bisphenol F diglycidyl ether, tetrabromobisphenol A diglycidyl ether, or hydroquinone diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, resorcinol diglycidyl ether, bisphenol A polyethylene glycol diglycidyl ether, and diglycidyl esters of dicarboxylic acids such as terephthalic acid diglycidyl. These preferably have a molecular weight of 700 or less.

[0046] Examples of chain extenders (B) having an isocyanate group in Y1 include terephthaloyl biscaprolactam and isophthaloyl biscaprolactam.

[0047] Examples of chain extenders (B) in which Y1 is an oxazolyl group or an oxazine group include bisoxazoline and bisoxazine, where A' is a single covalent bond; and 1,3-bis(4,5-dihydro-2-oxazolyl)benzene and 1,4-bis(4,5-dihydro-2-oxazolyl)benzene, where A' is an arylene group, such as a 1,2-phenylene group, a 1,3-phenylene group, a 1,4-phenylene group, a naphthalene group, or an isophthaloyl group.

[0048] Examples of chain extenders (B) in which Y1 is an imidazoline group include bisimidazolin and, for example, the compounds described in European Patent No. 0739924. Examples of chain extenders (B) in which Y1 is an oxazinon group or an oxazolinone group include bis(benzoxazinon), bisoxazinon, bisoxazolinone, and compounds described, for example, in European Patent No. 0581641.

[0049] Examples of chain extenders (B) in which Y1 is an aziridine group include 1,1'-isophthaloylbis(2-methylaziridine).

[0050] In this embodiment, it is preferable that the chain extender (B) contains an oxazolyl group. More specifically, from the viewpoint of enabling the polyamide resin to exhibit excellent moldability (processability) and durability (fatigue resistance), it is more preferable that the chain extender (B) is 1,3-bis(4,5-dihydro-2-oxazolyl)benzene or 1,4-bis(4,5-dihydro-2-oxazolyl)benzene.

[0051] There are no particular restrictions on the number-average molecular weight of the chain extender (B), but it is preferably 100 to 700, more preferably 150 to 400, and even more preferably 200 to 300.

[0052] When polymer block (A) has terminal carboxyl groups and chain extender (B) is 1,4-bis(4,5-dihydro-2-oxazolyl)benzene, the resulting reaction product has the following structure: -OC(O)-PC(O)-OR 1 -NHC(O)-A'-C(O)NH-R 1 - (In the formula, P represents the remainder of polymer block (A) excluding the terminal carboxyl groups, R 1 It has at least one repeating unit having ) where is an ethylene group and A' is a phenylene group.

[0053] <Method for producing polyamide resins> The polyamide resin of this embodiment can be produced, for example, by dry blending the polymer constituting the polymer block (A) and the chain extender (B) in the absence of the end-functionalizing agent and the end-encapsulating agent, and then melt-kneading the mixture. Alternatively, the polyamide resin can be produced by dry blending the polymer constituting the polymer block (A) and the chain extender (B) in the presence of the end-functionalizing agent and / or the end-encapsulating agent, and then melt-kneading the mixture. Alternatively, the end functional groups of the polymer block (A) may be adjusted by reacting the semi-aromatic polyamide, which is the polymer constituting the polymer block (A), with the end-functionalizing agent and / or the end-encapsulating agent, followed by pulverization, then adding the chain extender (B), dry-blending, and then melt-kneading the mixture. Furthermore, the semi-aromatic polyamide polymer constituting the polymer block (A) and the end-functionalizing agent and / or end-sealing agent may be introduced from the upper hopper of the melt kneader and reacted, after which the chain extender (B) may be added from the side feed port on the downstream side of the extruder to perform stepwise melt kneading. Typically, methods such as melt polymerization, solid-phase polymerization, and melt extrusion polymerization can be employed. A solid-phase polymerization method may be combined with melt polymerization or melt extrusion polymerization. For melt extrusion polymerization, a method of melt kneading using a single-screw extruder, twin-screw extruder, kneader, Banbury mixer, etc., is preferably employed. The melt kneading conditions are not particularly limited, but for example, a method of melt kneading for about 1 to 60 minutes at a temperature range about 0 to 60°C higher than the melting point of the polyamide is preferred from the viewpoint of making the effects of the present invention more easily realized. Furthermore, the reaction between the polymer constituting the polymer block (A) and the chain extender (B) is usually a ring-opening addition polymerization reaction, so condensation water is not produced.

[0054] <Usage ratio> In the polyamide resin of this embodiment, the ratio of the amount of chain extender (B) used to the polymer block (A) is preferably 91.0 / 9.0~98.9 / 1.1, more preferably 92.0 / 8.0~98.7 / 1.3, even more preferably 93.5 / 6.5~98.5 / 1.5, and even more preferably 95.0 / 5.0~98.3 / 1.7, expressed as a mass ratio of (A) / (B), from the viewpoint of providing moldability and excellent fatigue resistance while maintaining the heat resistance of the resulting polyamide resin. Note that, normally, the polymer block (A) and the chain extender (B) react completely, so the above usage ratio represents the content ratio in the polyamide resin.

[0055] <Molecular weight of polyamide resins> The number-average molecular weight of the polyamide resin is not particularly limited, but is preferably 4,000 to 15,000, more preferably 5,000 or more and less than 10,000, even more preferably 5,000 to 9,000, and even more preferably 5,000 to 8,000. Higher molecular weights result in better heat resistance, but tend to decrease moldability. Within the above numerical range, the heat resistance of the polyamide resin can be further improved and good moldability can be expected. The weight-average molecular weight of the polyamide resin is not particularly limited as long as it is between 40,000 and 150,000, but is preferably between 42,000 and 150,000, more preferably between 43,000 and 120,000, even more preferably between 45,000 and 100,000, and even more preferably between 50,000 and 90,000. Within the above numerical range, the polyamide resin can be expected to exhibit tougher material properties and have good moldability.

[0056] <Physical properties> <<Melting point>> The melting point of polyamide resins is usually preferably 230°C or higher, as this ensures good thermal stability of molded articles obtained using polyamide resins. The melting point of the polyamide resin is preferably 235°C or higher, more preferably 240°C or higher. There is no particular upper limit to the melting point of the polyamide resin, but from the viewpoint of moldability and other factors, it is preferable that it be 315°C or lower.

[0057] <<Melting viscosity>> The polyamide resin of this embodiment has a melt viscosity of preferably 50 to 1000 Pa·s, more preferably 60 to 900 Pa·s, and even more preferably 70 to 800 Pa·s. In this specification, melt viscosity is an indicator of moldability (processability). If the melt viscosity is in the range of 50 to 1000 Pa·s, polyamide resins can be said to have excellent moldability. The above melt viscosity can be determined more specifically by the method described in the examples below.

[0058] <<Fatigue resistance>> For the polyamide resin of this embodiment, the time strength under tensile load conditions, measured in accordance with JIS K 7118:1995, is preferably 10 at a stress of 30 MPa. 7 More than 10 times, more preferably under a stress of 40 MPa 7 It is more than once. In this specification, the above-mentioned time strength is an indicator of fatigue resistance. The above-mentioned time strength is 10 at a stress of 30 MPa. 7 If the number of cycles exceeds a certain limit, polyamide resins can be said to have excellent fatigue resistance. The above time intensity can be determined more specifically by the method described in the examples below.

[0059] [Polyamide resin composition] As one embodiment of this invention, a polyamide resin composition containing the above-mentioned polyamide resin can be used. The polyamide resin composition contains the above-mentioned polyamide resin along with additives other than the polyamide resin. Examples of additives include antioxidants, ozone cracking inhibitors, weather stabilizers, ultraviolet absorbers, hydrolysis-resistant stabilizers, fillers, nucleating agents, strengthening agents, carbon black, pigments, inorganic dyes, organic dyes, colorants, color inhibitors, gelation inhibitors, matting agents, antistatic agents, plasticizers, lubricants, mold release agents, shrinkage-resistant agents, compatibilizers, flame retardants, flame retardant aids, and foaming agents. These may contain only one type, or two or more types. The additive content is preferably 0.01 to 100 parts by mass, more preferably 0.1 to 10 parts by mass, and even more preferably 0.3 to 5 parts by mass, per 100 parts by mass of polyamide resin. Methods for adding the above-mentioned additives include, for example, adding them during the polymerization of the polyamide resin, or dry blending them with the polyamide resin and then melt-kneading them together.

[0060] In this embodiment, it is preferable that the additive is at least one of a nucleating agent, a reinforcing agent, an antioxidant, and a lubricant, from the viewpoint of heat resistance, moldability (processability), and durability (fatigue resistance) of the polyamide resin composition.

[0061] Examples of nucleating agents include talc and carbon black. The average particle size of the talc is preferably 1 to 20 μm. This average particle size can be determined by image analysis using electron microscopy. Specifically, the major and minor axes are measured for 1000 or more talc particles photographed using a transmission electron microscope, and the average value is taken as the average particle size. If the polyamide resin composition of this embodiment contains a nucleating agent, its content is preferably 0.05 to 1.0% by mass relative to the total mass of the polyamide resin composition.

[0062] Reinforcing agents can be used in various forms, such as fibrous, plate-like, needle-like, powder-like, or cloth-like. Specifically, examples include fibrous fillers such as glass fibers, carbon fibers, aramid fibers, liquid crystal polymer (LCP) fibers, and metal fibers; plate-shaped fillers such as mica; needle-shaped fillers such as potassium titanate whiskers, aluminum borate whiskers, calcium carbonate whiskers, magnesium sulfate whiskers, wollastonite, sepiolite, xonotlite, and zinc oxide whiskers; and powdered fillers such as silica, alumina, barium carbonate, magnesium carbonate, aluminum nitride, boron nitride, titanium dioxide, potassium titanate, aluminum silicate (kaolin, clay, pyrophyllite, bentonite), calcium silicate, magnesium silicate (atapulgite), magnesium oxide, aluminum borate, calcium sulfate, barium sulfate, magnesium sulfate, asbestos, glass beads, graphite, carbon nanotubes, silicon carbide, sericite, hydrotalcite, molybdenum disulfide, phenolic resin particles, cross-linked styrene resin particles, and cross-linked acrylic resin particles. These reinforcing agents may be used individually or in combination of two or more.

[0063] The surface of the reinforcing agent may be surface-treated with a silane coupling agent, a titanium coupling agent, a polymer compound such as an acrylic resin, a urethane resin, or an epoxy resin, or other low-molecular-weight compound, for the purpose of improving dispersibility in the polyamide resin or improving adhesion to the polyamide resin.

[0064] Among the reinforcing agents mentioned above, at least one selected from the group consisting of fibrous fillers and needle-shaped fillers is preferred because it is low-cost and yields molded articles with high mechanical strength. From the viewpoint of high strength and low cost, glass fibers are preferred as the reinforcing agent, and from the viewpoint of yielding molded articles with high surface smoothness, needle-shaped fillers are preferred. As the reinforcing agent, at least one selected from the group consisting of glass fibers, wollastonite, potassium titanate whiskers, calcium carbonate whiskers, and aluminum borate whiskers can be preferably used, and at least one selected from the group consisting of glass fibers and wollastonite is more preferably used.

[0065] The average fiber length of the glass fibers is preferably 1 to 10 mm, more preferably 1 to 7 mm, and even more preferably 2 to 4 mm. Furthermore, the average fiber diameter of the glass fibers is preferably 6 to 20 μm, and more preferably 6 to 15 μm, from the viewpoint of obtaining mechanical strength. The average aspect ratio of wollastonite is preferably 3 or higher, more preferably 5 or higher, and even more preferably 10 or higher, from the viewpoint of obtaining mechanical strength. The average fiber diameter of wollastonite is preferably 0.1 to 15 μm, more preferably 2.0 to 7.0 μm. The average fiber length, average fiber diameter, and average aspect ratio mentioned above can be determined by image analysis using electron microscopy. If the polyamide resin composition of this embodiment contains a reinforcing agent, the amount of the reinforcing agent is preferably 0.05 to 100 parts by mass per 100 parts by mass of the polyamide resin.

[0066] Examples of antioxidants include hindered phenol antioxidants, hindered amine antioxidants, phosphorus antioxidants, and thio antioxidants. Hindered phenol antioxidants can be commercially available, such as "Adekastab AO-20", "Adekastab AO-50", "Adekastab AO-80" (product names, all manufactured by ADEKA Corporation); "IRGANOX1010", "IRGANOX1076", "IRGANOX1035", "IRGANOX1098", "IRGANOX245", "IRGANOX259" (product names, all manufactured by BASF Japan Ltd.); and "Sumilizer GA-80" (product name, manufactured by Sumitomo Chemical Co., Ltd.). As a hindered amine antioxidant, HALS (Hindered Amine Light Stabilizer) can be used, such as "Tinuvin770DF" (trade name, manufactured by BASF Japan Ltd.). Examples of phosphorus-based antioxidants include phosphite esters, phosphonic acid esters, and oxaphosphaphenanthrene oxide. Commercially available phosphorus-based antioxidants can be used, such as "IRGAFOS168" (trade name, manufactured by BASF Japan Ltd.), "Hostanox P-EPQ" (trade name, manufactured by Clariant Japan Co., Ltd.), and "GSY-P101" (trade name, manufactured by Sakai Chemical Industry Co., Ltd.). Examples of thio-based antioxidants include the organic sulfur-based secondary antioxidant "Sumilizer TP-D" manufactured by Sumitomo Chemical Co., Ltd. Other antioxidants and stabilizers used for similar purposes include UV inhibitors such as Tinuvin 312 from BASF Japan Ltd., amine-based antioxidants such as Naugard 445 from Addivant, multifunctional stabilizers such as Nylostab S-EED from Clariant Chemicals, or mineral stabilizers such as copper-based stabilizers. Examples of mineral stabilizers include copper halides and copper acetate. Secondly, other metals such as silver can be considered selectively, although their effect is known to be weak. These copper-containing compounds typically bind with alkali metal halides, especially potassium halides. If the polyamide resin composition of this embodiment contains an antioxidant, the amount is preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the polyamide resin.

[0067] Examples of lubricants commonly added to resins as internal or external lubricants include amides of higher fatty acids such as stearic acid and montanic acid, their esters, and metal salts such as calcium thereof. If the polyamide resin composition of this embodiment contains a lubricant, its content is preferably 0.05 to 5 parts by mass, and more preferably 0.1 to 3 parts by mass, per 100 parts by mass of the polyamide resin.

[0068] <Method for producing polyamide resin compositions> There are no particular restrictions on the method for producing the polyamide resin composition, and a method that can uniformly mix the polyamide resin and the above-mentioned additives is preferably employed. Mixing is usually preferably carried out by melt kneading using a single-screw extruder, twin-screw extruder, kneader, Banbury mixer, etc. The melt kneading conditions are not particularly limited, but for example, a method of melt kneading for about 1 to 60 minutes at a temperature range about 0 to 60°C higher than the melting point of the polyamide resin can be used.

[0069] [Molded products] As one embodiment of this invention, a molded article made from the above-mentioned polyamide resin or polyamide resin composition can be provided. The molded articles of this embodiment can be used as various molded articles of any shape and application, including electrical and electronic components, automotive parts, industrial parts, textiles, films, sheets, household goods, and more.

[0070] <Application> The polyamide resin and polyamide resin composition of this embodiment exhibit excellent heat resistance, moldability, and durability (fatigue resistance), making them suitable for use in a wide range of fields where these properties are required. For example, the polyamide resin and polyamide resin composition of this embodiment can be widely used as materials for various components such as electrical and electronic components, automotive parts, industrial materials, industrial parts, daily necessities, household goods, sports equipment, leisure equipment, and medical equipment. [Examples]

[0071] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way by such examples.

[0072] <Measurement and Evaluation Methods> Various physical properties were measured or evaluated using the following methods.

[0073] <<Molecular weight>> The semi-aromatic polyamide produced in the synthesis example used as polymer block (A), and the polyamide resins and polyamide resin compositions obtained in the examples and comparative examples were used as samples, and their number-average molecular weight (Mn), weight-average molecular weight (Mw), peak-top molecular weight (Mp), and molecular weight distribution (Mw / Mn) were determined as standard polymethyl methacrylate-based molecular weights by gel permeation chromatography (GPC). A solution of 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) was prepared by dissolving sodium trifluoroacetate in a ratio of 0.85 g per 1 kg of HFIP. 1.5 mg of the sample (in resin equivalent) was weighed and dissolved in 3 mL of the above eluent. The solution was then passed through a 0.4 μm membrane filter to prepare the measurement sample. The measurement conditions were as follows: (Measurement conditions) Equipment: HLC-8320GPC (manufactured by Tosoh Corporation) Column: Two TSK gel Super HM-H columns (manufactured by Tosoh Corporation) were connected in series. Eluent: 0.085% sodium trifluoroacetate / HFIP solution Flow rate: 0.5 mL / min (Reference column: 0.25 mL / min) Sample injection volume: 30 μL Column temperature: 40℃ Standard polymethyl methacrylate: Showa Denko Corporation Shodex Standard M-75, Agilent Technologies, Inc. Polymeth y l-methacrylate molecular weight 1010 and molecular weight 535 Detectors: UV (254nm) detector, UV (210nm) detector

[0074] <<Measurement of terminal amino group content ([NH2])>> The semi-aromatic polyamide prepared in the synthesis example was used as the sample. 1 g of the sample was dissolved in 35 ml of phenol, and 3 ml of methanol was mixed to prepare the sample solution. Titration was performed using thymol blue as an indicator and a 0.01 or 0.1 N aqueous HCl solution to measure the terminal amino group content ([NH2], unit: μmol / g).

[0075] <<Measurement of terminal carboxyl group content ([COOH])>> The semi-aromatic polyamide prepared in the synthesis example was used as the sample. 0.5 g of the sample was dissolved in 40 ml of ortho-cresol to prepare the sample solution. A potentiometric titration was performed using a 0.01 or 0.1 N KOH / EtOH solution, and the terminal carboxyl group content ([COOH], unit: μmol / g) was measured. (Measurement conditions) Measurement device: MCU-710M / S (manufactured by Kyoto Electronics Manufacturing Co., Ltd.) Measurement unit: AT-710 Main control unit: MCU-710

[0076] <<Active terminal functional group content>> Using the [NH2] and [COOH] content of each functional group [NH2] and [COOH] of the semi-aromatic polyamide obtained from the above measurements of terminal amino group content and terminal carboxyl group content, the active terminal functional group content of polymer block (A) was calculated from the following formula. <formula>: Active terminal functional group content (μmol / g)=([NH2]+[COOH])

[0077] <<Melting point>> The semi-aromatic polyamides produced in the synthesis example, and the polyamide resins or polyamide resin compositions obtained in the examples and comparative examples were used as samples, and their melting points were measured using a differential scanning calorimetry analyzer "DSC822e" manufactured by Mettler Toledo K.K. The melting point was measured in accordance with ISO 11357-3 (2nd edition, 2011). Specifically, the sample was heated from 30°C to 340°C at a rate of 10°C / min under a nitrogen atmosphere, held at 340°C for 5 minutes to completely melt the sample, and then 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 appeared when the temperature was raised again to 340°C at a rate of 10°C / min was defined as the melting point (°C). If there were multiple melting peaks, the peak temperature of the highest temperature melting peak was defined as the melting point (°C).

[0078] <<Melting viscosity>> Each component was pre-mixed in the proportions (parts by mass) shown in Table 3 or Table 4. 5 to 20 g of the prepared mixed sample was melt-kneaded for 2 to 15 minutes at a cylinder temperature 10 to 50°C higher than the melting point of the polymer block (A) using an Xplore Instruments tabletop compact kneader ("Xplore MC15"), extruded, cooled, and cut to produce pelletized polyamide resin or polyamide resin composition. The pellets of polyamide resin or polyamide resin composition prepared by the above method were subjected to a capillograph (manufactured by Toyo Seiki Seisakusho Co., Ltd.) at a barrel temperature of 280-340°C and a shear rate of 121.6 sec. -1 The melt viscosity (Pa·s) was measured under the conditions of (capillary: inner diameter 1.0 mm × length 10 mm, extrusion speed 10 mm / min) and used as an indicator of moldability.

[0079] <<Evaluation of fatigue resistance by tensile fatigue testing>> Mix the respective components in the ratios (parts by mass) shown in Table 3 or Table 4 in advance, and melt-knead 5 to 20 g of the prepared mixed sample using a bench-top small kneader (Xplore MC15 manufactured by Xplore Instruments) at a cylinder temperature 10 to 50 °C higher than the melting point of the polymer block (A) for 2 to 15 minutes. Then, under the conditions of a mold temperature of 120 to 200 °C and an injection pressure of 0.1 to 7.0 bar for an injection molding machine T runner mold, a small test piece type 1BA (2 mm thick, total length 75 mm, parallel part length 30 mm, parallel part width 5 mm) for tensile fatigue evaluation was produced. Using the test pieces prepared above, in accordance with JIS K 7118:1995, a tensile fatigue tester (tensile fatigue tester FT-5 manufactured by Saginomiya Seisakusho Co., Ltd.) was used to measure the time strength under the condition of applying a tensile load with a sine wave at 23 °C and a frequency of 30 Hz, and evaluated according to the following criteria (number of load cycles at a constant stress). A and B are qualified, and C and D are unqualified. A: 10 or more 7 cycles B: 10 or more 7 cycles C: 10 or more 6 cycles D: less than 10 6 cycles

[0080] <Polymer block (A)> As components of the polymer block (A), PA-1 to 9 produced in the following synthesis examples were used. (Synthesis Example 1) Production of semi-aromatic polyamide (PA-1) 1059.9 g (6.38 mol) of terephthalic acid, 918.0 g (5.80 mol) of a mixture of 1,9-nonanediamine and 2-methyl-1,8-octanediamine (molar ratio 85 / 15), 1.98 g of sodium hypophosphite monohydrate (0.1% by mass relative to the total mass of raw materials), and 770 mL of distilled water were placed in a 5 L autoclave and purged with nitrogen. The mixture was stirred at 100 °C for 30 minutes, and the temperature inside the autoclave was raised to 220 °C over 3 hours. At this time, the pressure inside the autoclave was increased to 2.0 MPa. Heating was continued for 2 hours while maintaining the pressure at 2.0 MPa, and the reaction was allowed to proceed while gradually releasing the water vapor. The reaction was continued for another hour to obtain a prepolymer. The obtained prepolymer was dried at 120 °C under reduced pressure for 24 hours and then pulverized to a particle size of 1 mm or less. This was subjected to solid-phase polymerization at 230°C and 13 Pa (0.1 mmHg) for 10 hours to obtain polymer block (A). This polymer block (A) is abbreviated as semi-aromatic polyamide "PA-1".

[0081] (Synthesis Example 2) Manufacturing of semi-aromatic polyamide (PA-2) 1043.8 g (6.28 mol) of terephthalic acid, 965.5 g (6.10 mol) of a mixture of 1,9-nonanediamine and 2-methyl-1,8-octanediamine (molar ratio 85 / 15), 2.01 g of sodium hypophosphite monohydrate (0.1% by mass relative to the total mass of raw materials), and 782 mL of distilled water were placed in a 5 L autoclave and purged with nitrogen. The mixture was stirred at 100 °C for 30 minutes, and the temperature inside the autoclave was raised to 220 °C over 3 hours. At this time, the pressure inside the autoclave was increased to 2.0 MPa. Heating was continued for 2 hours while maintaining the pressure at 2.0 MPa, and the reaction was allowed to proceed while gradually releasing the water vapor. The reaction was continued for another hour to obtain a prepolymer. The obtained prepolymer was dried at 120 °C under reduced pressure for 24 hours and then pulverized to a particle size of 1 mm or less. This was subjected to solid-phase polymerization at 230°C and 13 Pa (0.1 mmHg) for 10 hours to obtain polymer block (A). This polymer block (A) is abbreviated as semi-aromatic polyamide "PA-2".

[0082] (Synthesis Example 3) Manufacturing of semi-aromatic polyamide (PA-3) 1016.7 g (6.12 mol) of terephthalic acid, 949.7 g (6.00 mol) of a mixture of 1,9-nonanediamine and 2-methyl-1,8-octanediamine (molar ratio 85 / 15), 1.97 g of sodium hypophosphate monohydrate (0.1% by mass relative to the total mass of raw materials), and 766 mL of distilled water were placed in a 5 L autoclave and purged with nitrogen. The mixture was stirred at 100 °C for 30 minutes, and the temperature inside the autoclave was raised to 220 °C over 3 hours. At this time, the pressure inside the autoclave was increased to 2.0 MPa. Heating was continued for 2 hours while maintaining the pressure at 2.0 MPa, and the reaction was allowed to proceed while gradually releasing the water vapor. The reaction was continued for another hour to obtain a prepolymer. The obtained prepolymer was dried at 120 °C under reduced pressure for 24 hours and then pulverized to a particle size of 1 mm or less. This was subjected to solid-phase polymerization at 230°C and 13 Pa (0.1 mmHg) for 10 hours to obtain polymer block (A). This polymer block (A) is abbreviated as semi-aromatic polyamide "PA-3".

[0083] (Synthesis Example 4) Manufacturing of semi-aromatic polyamide (PA-4) 1006.7g (6.06 mol) of terephthalic acid, 949.7g (6.00 mol) of a mixture of 1,9-nonanediamine and 2-methyl-1,8-octanediamine (molar ratio 85 / 15), 1.96g of sodium hypophosphate monohydrate (0.1% by mass relative to the total mass of raw materials), and 762mL of distilled water were placed in a 5L autoclave and purged with nitrogen. The mixture was stirred at 100°C for 30 minutes, and the temperature inside the autoclave was raised to 220°C over 3 hours. At this time, the pressure inside the autoclave was increased to 2.0 MPa. Heating was continued for 2 hours while maintaining the pressure at 2.0 MPa, and the reaction was allowed to proceed while gradually releasing the water vapor. The reaction was continued for another hour to obtain a prepolymer. The obtained prepolymer was dried at 120°C under reduced pressure for 24 hours and then pulverized to a particle size of 1 mm or less. This was subjected to solid-phase polymerization at 230°C and 13 Pa (0.1 mmHg) for 10 hours to obtain polymer block (A). This polymer block (A) is abbreviated as semi-aromatic polyamide "PA-4".

[0084] (Synthesis Example 5) Manufacturing of semi-aromatic polyamide (PA-5) 1043.8 g (6.28 mol) of terephthalic acid, 965.5 g (6.10 mol) of a mixture of 1,9-nonanediamine and 2-methyl-1,8-octanediamine (molar ratio 50 / 50), 2.00 g of sodium hypophosphate monohydrate (0.1% by mass relative to the total mass of raw materials), and 782 mL of distilled water were placed in a 5 L autoclave and purged with nitrogen. The mixture was stirred at 100 °C for 30 minutes, and the temperature inside the autoclave was raised to 220 °C over 3 hours. At this time, the pressure inside the autoclave was increased to 2.0 MPa. Heating was continued for 2 hours while maintaining the pressure at 2.0 MPa, and the reaction was allowed to proceed while gradually releasing the water vapor. The reaction was continued for another hour to obtain a prepolymer. The obtained prepolymer was dried at 120 °C under reduced pressure for 24 hours and then pulverized to a particle size of 1 mm or less. This was subjected to solid-phase polymerization at 230°C and 13 Pa (0.1 mmHg) for 10 hours to obtain polymer block (A). This polymer block (A) is abbreviated as semi-aromatic polyamide "PA-5".

[0085] (Synthesis Example 6) Manufacturing of semi-aromatic polyamide (PA-6) 992.5 g (5.97 mol) of terephthalic acid, 999.4 g (5.80 mol) of 1,10-decanediamine, 1.99 g (0.1% by mass of the total mass of raw materials) of sodium hypophosphate monohydrate, and 775 mL of distilled water were placed in a 5 L autoclave and purged with nitrogen. The mixture was stirred at 100 °C for 30 minutes, and the temperature inside the autoclave was raised to 220 °C over 3 hours. At this time, the pressure inside the autoclave was increased to 2.0 MPa. Heating was continued for 2 hours while maintaining the pressure at 2.0 MPa, and the reaction was allowed to proceed while gradually releasing the water vapor. The reaction was continued for another hour to obtain a prepolymer. The obtained prepolymer was dried at 120 °C under reduced pressure for 24 hours and pulverized to a particle size of 1 mm or less. This was solid-phase polymerized at 230 °C and 13 Pa (0.1 mmHg) for 10 hours to obtain polymer block (A). This polymer block (A) is abbreviated as the semi-aromatic polyamide "PA-6".

[0086] (Synthesis Example 7) Manufacturing of semi-aromatic polyamide (PA-7) 1116.4 g (6.72 mol) of terephthalic acid, 886.4 g (5.60 mol) of a mixture of 1,9-nonanediamine and 2-methyl-1,8-octanediamine (molar ratio 50 / 50), 2.00 g of sodium hypophosphate monohydrate (0.1% by mass relative to the total mass of raw materials), and 780 mL of distilled water were placed in a 5 L autoclave and purged with nitrogen. The mixture was stirred at 100 °C for 30 minutes, and the temperature inside the autoclave was raised to 220 °C over 3 hours. At this time, the pressure inside the autoclave was increased to 2.0 MPa. Heating was continued for 2 hours while maintaining the pressure at 2.0 MPa, and the reaction was allowed to proceed while gradually releasing the water vapor. The reaction was continued for another hour to obtain a prepolymer. The obtained prepolymer was dried at 120 °C under reduced pressure for 24 hours and then pulverized to a particle size of 1 mm or less. This was subjected to solid-phase polymerization at 230°C and 13 Pa (0.1 mmHg) for 10 hours to obtain polymer block (A). This polymer block (A) is abbreviated as semi-aromatic polyamide "PA-7".

[0087] (Synthesis Example 8) Manufacturing of semi-aromatic polyamide (PA-8) 1015.6 g (6.11 mol) of terephthalic acid, 988.2 g (6.24 mol) of a mixture of 1,9-nonanediamine and 2-methyl-1,8-octanediamine (molar ratio 80 / 20), 21.2 g (0.17 mol) of benzoic acid, 2.02 g of sodium hypophosphate monohydrate (0.1% by mass relative to the total mass of raw materials), and 788 mL of distilled water were placed in a 5 L autoclave and purged with nitrogen. The mixture was stirred at 100 °C for 30 minutes, and the temperature inside the autoclave was raised to 220 °C over 3 hours. At this time, the pressure inside the autoclave was increased to 2.0 MPa. Heating was continued for 2 hours while maintaining the pressure at 2.0 MPa, and the reaction was allowed to proceed while gradually releasing the water vapor. The reaction was continued for another hour to obtain a prepolymer. The obtained prepolymer was dried at 120 °C under reduced pressure for 24 hours and then pulverized to a particle size of 1 mm or less. This was subjected to solid-phase polymerization at 230°C and 13 Pa (0.1 mmHg) for 10 hours to obtain polymer block (A). This polymer block (A) is abbreviated as semi-aromatic polyamide "PA-8".

[0088] (Synthesis Example 9) Manufacturing of semi-aromatic polyamide (PA-9) 1017.6 g (6.13 mol) of terephthalic acid, 988.2 g (6.24 mol) of a mixture of 1,9-nonanediamine and 2-methyl-1,8-octanediamine (molar ratio 50 / 50), 18.2 g (0.15 mol) of benzoic acid, 2.02 g of sodium hypophosphite monohydrate (0.1% by mass relative to the total mass of raw materials), and 788 mL of distilled water were placed in a 5 L autoclave and purged with nitrogen. The mixture was stirred at 100 °C for 30 minutes, and the temperature inside the autoclave was raised to 220 °C over 3 hours. At this time, the pressure inside the autoclave was increased to 2.0 MPa. Heating was continued for 2 hours while maintaining the pressure at 2.0 MPa, and the reaction was allowed to proceed while gradually releasing the water vapor. The reaction was continued for another hour to obtain a prepolymer. The obtained prepolymer was dried at 120 °C under reduced pressure for 24 hours and then pulverized to a particle size of 1 mm or less. This was subjected to solid-phase polymerization at 230°C and 13 Pa (0.1 mmHg) for 10 hours to obtain polymer block (A). This polymer block (A) is abbreviated as semi-aromatic polyamide "PA-9".

[0089] The various physical property evaluations described above were performed on PA-1 to PA-9. The results are shown in Table 1. The notation in Table 1 is as follows: "n / i" indicates the molar ratio of the linear diamine unit 1,9-nonanediamine to the branched diamine unit 2-methyl-1,8-octanediamine. In PA-6, the linear diamine unit is 1,10-decanediamine. "[NH2]" indicates the terminal amino group content. "[COOH]" indicates the content of terminal carboxyl groups.

[0090] [Table 1]

[0091] <Chain extender (B)> The following was used as the chain extender (B): • 1,3-PBO: 1,3-bis(4,5-dihydro-2-oxazolyl)benzene, manufactured by Tokyo Chemical Industry Co., Ltd. • 1,4-PBO: 1,4-bis(4,5-dihydro-2-oxazolyl)benzene, manufactured by Tokyo Chemical Industry Co., Ltd.

[0092] The physical properties of the chain extender (B) are shown in Table 2. The notation in Table 2 is as follows: "Mn" indicates the number-average molecular weight (catalog value). The "content of active terminal functional groups" is the value obtained from the following formula. <formula>: Active terminal functional group content (μmol / g)=2÷(chain extender molecular weight)×1,000,000

[0093] [Table 2]

[0094] <Examples 1-9, Comparative Examples 1-6> (Example 1) Using the semi-aromatic polyamide "PA-1" as the polymer block (A) and 1,3-bis(4,5-dihydro-2-oxazolyl)benzene (1,3-PBO) as the chain extender (B), 5 to 20 g of the prepared mixed sample was pre-mixed in the proportions shown in Table 3. This mixed sample was then melt-kneaded for 2 to 15 minutes at a cylinder temperature 10 to 50°C higher than the melting point of polymer block (A) using an Xplore Instruments tabletop compact kneader ("Xplore MC15"), extruded, cooled, and cut to produce pellet-shaped polyamide resin or polyamide resin composition. For tensile evaluation, the mixed sample prepared in the same manner as above was melt-kneaded, and then a small test specimen type 1BA (2 mm thick, 75 mm total length, 30 mm parallel section length, 5 mm parallel section width) for tensile fatigue evaluation was prepared using an injection molding machine T-runner mold under conditions of a mold temperature of 120 to 200°C and an injection pressure of 0.1 to 7.0 bar.

[0095] (Example 2) Polyamide resin pellets and dumbbell test pieces were manufactured in the same manner as in Example 1, except that semi-aromatic polyamide "PA-2" was used instead of semi-aromatic polyamide "PA-1" as polymer block (A), and the blending amounts were changed as shown in Table 3.

[0096] (Example 3) Polyamide resin pellets and dumbbell test pieces were manufactured in the same manner as in Example 1, except that semi-aromatic polyamide "PA-3" was used instead of semi-aromatic polyamide "PA-1" as polymer block (A), and the blending amounts were changed as shown in Table 3.

[0097] (Example 4) Polyamide resin pellets and dumbbell test pieces were manufactured in the same manner as in Example 1, except that semi-aromatic polyamide "PA-4" was used instead of semi-aromatic polyamide "PA-1" as polymer block (A), and the blending amounts were changed as shown in Table 3.

[0098] (Example 5) Polyamide resin pellets and dumbbell test pieces were manufactured in the same manner as in Example 1, except that semi-aromatic polyamide "PA-5" was used instead of semi-aromatic polyamide "PA-1" as polymer block (A), and the blending amounts were changed as shown in Table 3.

[0099] (Example 6) Polyamide resin pellets and dumbbell test pieces were manufactured in the same manner as in Example 1, except that semi-aromatic polyamide "PA-6" was used instead of semi-aromatic polyamide "PA-1" as polymer block (A), and the blending amounts were changed as shown in Table 3.

[0100] (Example 7) Polyamide resin pellets and dumbbell test pieces were prepared in the same manner as in Example 2, except that 1,4-bis(4,5-dihydro-2-oxazolyl)benzene (1,4-PBO) was used as the chain extender (B) instead of 1,3-bis(4,5-dihydro-2-oxazolyl)benzene (1,3-PBO).

[0101] (Example 8) Polyamide resin pellets and dumbbell test pieces were prepared in the same manner as in Example 5, except that 1,4-bis(4,5-dihydro-2-oxazolyl)benzene (1,4-PBO) was used as the chain extender (B) instead of 1,3-bis(4,5-dihydro-2-oxazolyl)benzene (1,3-PBO).

[0102] (Example 9) Pellets and dumbbell test pieces of polyamide resin composition were prepared in the same manner as in Example 2, except that 1 part by mass of lubricant (WH255) was further used per 100 parts by mass of polymer block (A).

[0103] (Comparative Example 1) Polyamide resin pellets and dumbbell test pieces were manufactured in the same manner as in Example 1, except that semi-aromatic polyamide "PA-7" was used instead of semi-aromatic polyamide "PA-1" as polymer block (A), and the blending amounts were changed as shown in Table 3.

[0104] (Comparative Example 2) Polyamide resin pellets and dumbbell test pieces were manufactured in the same manner as in Example 1, except that semi-aromatic polyamide "PA-8" was used instead of semi-aromatic polyamide "PA-1" as polymer block (A), and the blending amounts were changed as shown in Table 3.

[0105] (Comparative Example 3) Polyamide resin pellets and dumbbell test pieces were manufactured in the same manner as in Example 1, except that semi-aromatic polyamide "PA-9" was used instead of semi-aromatic polyamide "PA-1" as polymer block (A), and the blending amounts were changed as shown in Table 3.

[0106] (Comparative Example 4) Polyamide resin pellets and dumbbell test pieces were manufactured in the same manner as in Example 2, except that the melting and mixing time was changed to 1 minute.

[0107] (Comparative Example 5) Polyamide resin pellets and dumbbell test pieces were manufactured in the same manner as in Example 2, except that the formulation amounts were changed as shown in Table 3.

[0108] (Comparative Example 6) Polyamide resin pellets and dumbbell test pieces were manufactured in the same manner as in Example 2, except that the formulation amounts were changed as shown in Table 3.

[0109] The polyamide resins and polyamide resin compositions obtained in the above examples and comparative examples were used to evaluate various physical properties. The results of the physical property evaluation are shown in Table 3. The notation in Table 3 is as follows: "1,3-PBO" refers to "1,3-bis(4,5-dihydro-2-oxazolyl)benzene" manufactured by Tokyo Chemical Industry Co., Ltd. "1,4-PBO" refers to "1,4-bis(4,5-dihydro-2-oxazolyl)benzene" manufactured by Tokyo Chemical Industry Co., Ltd. "WH255" refers to "Light Amid WH-255" manufactured by Kyoeisha Chemical Industry Co., Ltd.

[0110] [Table 3]

[0111] (Example 10) A polyamide resin composition was obtained by compounding the polyamide resin obtained in Example 3 with a nucleating agent, antioxidant, and lubricant in the amounts shown in Table 4. Various physical properties were evaluated using the obtained polyamide resin composition. The results of the physical property evaluation are shown in Table 4. The notation in Table 4 is as follows: "ML-112" refers to "Talc ML112" manufactured by Fuji Talc Industrial Co., Ltd. "GA-80" refers to "SUMILIZER GA-80" manufactured by Sumitomo Chemical Co., Ltd. "Wax-OP" refers to "Licowax OP P" manufactured by Clariant Chemicals.

[0112] [Table 4]

[0113] From the results in Tables 3 and 4, it can be seen that Examples 1 to 10 have excellent heat resistance, moldability, and fatigue resistance. On the other hand, Comparative Examples 1 to 6 have excellent heat resistance, but cannot achieve both moldability and fatigue resistance. [Industrial applicability]

[0114] The polyamide resin of this embodiment is obtained by reaction of a polymer block (A) and a chain extender (B), and exhibits excellent heat resistance, moldability, and durability such as fatigue resistance. Therefore, the polyamide resin and polyamide resin composition of this embodiment can be widely used as a component material for various parts such as electrical and electronic components, automotive parts, industrial materials, industrial parts, daily necessities, household goods, sports equipment, leisure equipment, and medical equipment. In particular, it can be applied to complex-shaped parts by injection molding, hollow molded parts by blow molding, hose / tube-shaped parts and films / sheets by extrusion molding, lightweight members and heat insulating materials by injection and / or extrusion foam molding, and as an additive for resin modification.

Claims

1. A polyamide resin comprising a polymer block (A) containing 50 mol% or more of structural units derived from polyamide, and a group derived from a chain extender (B), The content of polymer blocks (A) in the polyamide resin is 91.0% by mass or more and less than 99% by mass. The weight-average molecular weight of the aforementioned polyamide resin is 40,000 to 150,000. The polyamide resin having a number average molecular weight of 4,000 to 15,000, The polyamide is a semi-aromatic polyamide, The semi-aromatic polyamide comprises a diamine unit derived from an aliphatic diamine and a dicarboxylic acid unit derived from an aromatic dicarboxylic acid. A polyamide resin comprising, as the aliphatic diamine-derived diamine unit, a diamine unit derived from at least one selected from the group consisting of 1,4-butanediamine, 1,6-hexanediamine, 1,9-nonanediamine, 2-methyl-1,8-octanediamine, 1,10-decanediamine, 1,11-undecanediamine, and 1,12-dodecanediamine, wherein the chain extender (B) contains an oxazolyl group. The weight-average molecular weight and number-average molecular weight were measured using the following methods. An HFIP solution prepared by dissolving sodium trifluoroacetate at a ratio of 0.85 g per 1 kg of 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) was used as the eluent. 1.5 mg of the sample (in resin equivalent) was weighed and dissolved in 3 mL of the above eluent. The solution was passed through a 0.4 μm membrane filter to prepare the measurement sample. The measurement conditions were as follows: (Measurement conditions) Equipment: HLC-8320GPC (manufactured by Tosoh Corporation) Column: Two TSK gel Super HM-H columns (manufactured by Tosoh Corporation) were connected in series. Eluent: 0.085% sodium trifluoroacetate / HFIP solution Flow rate: 0.5 mL / min (Reference column: 0.25 mL / min) Sample injection volume: 30 μL Column temperature: 40°C Standard polymethyl methacrylate: Showa Denko K.K. Shodex Standard M-75, Agilent Technologies, Inc. Polymethyl methacrylate Molecular weight 1010 and molecular weight 535 Detectors: UV (254 nm) detector, UV (210 nm) detector

2. The polyamide resin according to claim 1, wherein the semi-aromatic polyamide contains 30 mol% or more of diamine units derived from aliphatic diamines having 4 to 18 carbon atoms, relative to the total number of diamine units.

3. The polyamide resin according to claim 1 or 2, wherein the total content of units derived from aliphatic diamines having 4 to 18 carbon atoms and aromatic dicarboxylic acids relative to all constituent units of the semi-aromatic polyamide is 40 to 100 mol%.

4. The polyamide resin according to any one of claims 1 to 3, wherein the semi-aromatic polyamide contains a diamine unit derived from at least one selected from the group consisting of 1,9-nonanediamine and 2-methyl-1,8-octanediamine.

5. The polyamide resin according to any one of claims 1 to 4, wherein the chain extender (B) is 1,3-bis(4,5-dihydro-2-oxazolyl)benzene or 1,4-bis(4,5-dihydro-2-oxazolyl)benzene.

6. The polyamide resin according to any one of claims 1 to 5, wherein the active end functional group content of the polymer block (A) is 75 to 600 μmol / g.

7. The polyamide resin according to any one of claims 1 to 6, wherein the number average molecular weight of the polymer block (A) is 2,000 to 10,000.

8. The polyamide resin according to any one of claims 1 to 7, wherein the weight-average molecular weight of the polymer block (A) is 8,000 to 50,000.

9. The polyamide resin according to any one of claims 1 to 8, wherein the weight-average molecular weight of the polyamide resin is 42,000 to 150,000.

10. The weight-average molecular weight of the polyamide resin is 42,000 to 150,000. The polyamide is a semi-aromatic polyamide, The semi-aromatic polyamide comprises a diamine unit derived from an aliphatic diamine and a dicarboxylic acid unit derived from an aromatic dicarboxylic acid. The semi-aromatic polyamide comprises a diamine unit derived from at least one selected from the group consisting of 1,9-nonanediamine and 2-methyl-1,8-octanediamine. The chain extender (B) is 1,3-bis(4,5-dihydro-2-oxazolyl)benzene or 1,4-bis(4,5-dihydro-2-oxazolyl)benzene, The polyamide resin according to claim 1, wherein the active terminal functional group content of the polymer block (A) is 75 to 600 μmol / g.

11. A polyamide resin composition comprising a polyamide resin according to any one of claims 1 to 10 and an additive, A polyamide resin composition in which the content of the additive is 0.01 to 100 parts by mass per 100 parts by mass of the polyamide resin.

12. The polyamide resin composition according to claim 11, wherein the additive is at least one of a nucleating agent, a reinforcing agent, an antioxidant, and a lubricant.

13. The polyamide resin composition according to claim 12, A polyamide resin composition in which the lubricant content is 0.05 to 5 parts by mass per 100 parts by mass of the polyamide resin.

14. A molded article comprising a polyamide resin according to any one of claims 1 to 10 or a polyamide resin composition according to any one of claims 11 to 13.

Images