Polyamide resin composition and molded article

Abstract

To provide a polyamide resin composition and a molded article thereof which attain sufficient improvement in reflow resistance and also flame retardancy.SOLUTION: A polyamide resin composition comprising: a semi-aromatic polyamide resin (A) having a melting point of 280°C or higher as measured by differential scanning calorimetry (DSC); a flame retardant (B) which is a halogen-containing compound; and a fibrous reinforcing material (C) surface-treated with an epoxy-based sizing agent, wherein the fibrous reinforcing material (C) has a weight average fiber diameter (Dw) of 11 μm or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a polyamide resin composition and a molded article.

Background Art

[0002] Conventionally, polyamide resin compositions have been known as molding materials. Polyamide resin compositions are widely used, for example, as materials for various parts such as automotive parts and electrical and electronic parts, and are known to have excellent mechanical strength of the molded article. In particular, polyamide resin compositions containing semi-aromatic polyamide resins having a high melting point are known to be excellent for use at high temperatures because of their excellent heat resistance.

[0003] For example, Patent Document 1 discloses an aromatic polyamide comprising a dicarboxylic acid unit (a) containing 60 to 100 mol% of terephthalic acid units, and a diamine unit (b) containing 60 to 100 mol% of 1,9-nonamethylenediamine units (b-1) and / or 2-methyl-1,8-octamethylenediamine units (b-2), a polyphenylene ether, a compatibilizer for polyamide and polyphenylene ether, and a crystal nucleating agent, wherein the terminal amino group concentration of the aromatic polyamide is 5 μmol / g or more and 45 μmol / g or less. According to Patent Document 1, the resin composition is said to be excellent in heat resistance, impact strength, low water absorption, fluidity, and low linear expansibility. Further, Patent Document 1 describes that glass fibers are included in the polyamide resin composition in order to improve the mechanical properties of the molded article.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, when a molded article of a polyamide resin composition is used for automotive parts, electrical and electronic parts, etc., the molded article may be subjected to reflow soldering to a substrate. At this time, due to heating (reflow treatment) in the reflow process, the moisture contained in the molded article vaporizes, and blisters (swelling) may occur in the molded article due to the vapor pressure caused by the vaporization. From the viewpoint of improving the appearance and dimensional accuracy of the molded article, it is desirable to use a polyamide resin composition that is less likely to form blisters (has high reflow heat resistance) due to heating. Therefore, there is a demand for a polyamide resin composition with sufficiently enhanced reflow heat resistance.

[0006] In addition, since polyamide resin compositions are flammable, for example, in applications such as automotive parts and electrical and electronic parts, polyamide resin compositions with enhanced flame retardancy are required.

[0007] An object of the present invention is to provide a polyamide resin composition and a molded article of a polyamide resin composition that can enhance flame retardancy while sufficiently enhancing reflow heat resistance.

Means for Solving the Problems

[0008] One aspect of the present invention for solving the above problems relates to the polyamide resin compositions of the following [1] to [7]. [1] A semi-aromatic polyamide resin (A) having a melting point measured by a differential scanning calorimeter (DSC) of 280°C or higher, A flame retardant (B) which is a halogen-containing compound, A fibrous reinforcing material (C) surface-treated with an epoxy-based sizing agent, and The weight average fiber diameter (Dw) of the fibrous reinforcing material (C) is 11.0 μm or less, Polyamide resin composition. [2] The semi-aromatic polyamide resin (A) contains a component unit (Aa) derived from a dicarboxylic acid and a component unit (Ab) derived from a diamine, The component unit (Aa) derived from the dicarboxylic acid contains a component unit derived from terephthalic acid that is 75 mol% or less based on the total number of moles of the component unit (Aa) derived from the dicarboxylic acid. The polyamide resin composition according to [1]. [3] The semi-aromatic polyamide resin (A) has an end amino group amount of 30 mmol / kg or more and 200 mmol / kg or less. The polyamide resin composition according to [1] or [2]. [4] The fibrous reinforcing material (C) has an aspect ratio of less than 1.5 in cross-section. The polyamide resin composition according to any one of [1] to [3]. [5] The semi-aromatic polyamide resin (A) contains a component unit (Aa) derived from a dicarboxylic acid and a component unit (Ab) derived from a diamine. The component unit (Aa) derived from the dicarboxylic acid contains a component unit derived from terephthalic acid. The component unit (Ab) derived from the diamine contains a component unit derived from 1,6-diaminohexane. The polyamide resin composition according to any one of [1] to [4]. [6] The content of the component unit derived from 1,6-diaminohexane is 70 mol% or more and 100 mol% or less based on the total number of moles of the component unit (Ab) derived from the diamine. The polyamide resin composition according to [5].

[0009] Another aspect of the present invention for solving the above problems relates to a molded article of the following [7]. [7] A molded article obtained by molding the polyamide resin composition according to any one of [1] to [6]. Molded article.

Effect of the Invention

[0010] According to the present invention, it is possible to provide a polyamide resin composition and a molded article of the polyamide resin composition that can sufficiently enhance the reflow heat resistance while enhancing the flame retardancy.

Brief Description of the Drawings

[0011]

Figure 1

Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described in detail. Note that the present invention is not limited to the following embodiments.

[0013] 1. Polyamide resin composition The polyamide resin composition according to this embodiment includes a semi-aromatic polyamide resin (A) having a melting point of 280°C or higher measured by a differential scanning calorimeter (DSC), a flame retardant (B) which is a halogen-containing compound, and a fibrous reinforcing material (C) aggregated with an epoxy-based aggregating agent. In the above polyamide resin composition, the weight average fiber diameter (Dw) of the fibrous reinforcing material (C) is 11 μm or less.

[0014] The flame retardant (B) which is a halogen-containing compound can impart flame retardancy to the polyamide resin composition and its molded article. On the other hand, in a molded article formed using a polyamide resin composition containing the flame retardant (B), the reflow heat resistance decreases.

[0015] The flame retardant (B), which is a halogen-containing compound, has low affinity with the semi-aromatic polyamide resin (A), and it is considered that the strength at the interface between the semi-aromatic polyamide resin (A) and the flame retardant (B) (interface strength) is low. Therefore, it is considered that blisters starting from the above interface are likely to occur. In particular, as the flame retardant (B), which is a halogen-containing compound, widely used brominated polystyrene, polybrominated styrene, etc. have a lower melting point than the semi-aromatic polyamide resin (A). Therefore, compared with the case where the flame retardant (B) is not contained, the molded body is likely to soften during the reflow process, and it is considered that the mechanical strength of the molded body decreases. As a result, in the reflow process, it is considered that the molded body cannot withstand the vapor pressure when the moisture contained inside vaporizes, and blisters are likely to occur on the surface of the molded body. For these reasons, improving the flame retardancy of the molded body and improving the reflow heat resistance were in a trade-off relationship.

[0016] On the other hand, the inventors of the present invention tried to suppress the generation of blisters and improve the reflow heat resistance by including a fibrous reinforcing material in the polyamide resin composition to increase the mechanical strength of the molded body, but the reflow heat resistance of the molded body did not increase sufficiently.

[0017] Since the fibrous reinforcing material has low affinity with the semi-aromatic polyamide resin (A), it is considered that the strength at the interface between the fibrous reinforcing material and the semi-aromatic polyamide resin (A) (interface strength) is low. Therefore, it is considered that blisters starting from the above interface are likely to occur, and the reflow heat resistance was not increased sufficiently.

[0018] Therefore, the inventors of the present invention considered using a fibrous reinforcing material surface-treated with an epoxy-based sizing agent, which has high affinity with the semi-aromatic polyamide resin (A). However, that alone was not sufficient to increase the reflow heat resistance sufficiently. It is considered that by increasing the affinity of the fibrous reinforcing material with respect to the semi-aromatic polyamide resin (A), the shear stress generated at the interface between the fibrous reinforcing material and the semi-aromatic polyamide resin (A) during molding increased, and the interface strength did not increase sufficiently.

[0019] In view of these problems, the inventors have intensively studied and found that by including in the polyamide resin composition a fibrous reinforcing material (C) surface-treated with an epoxy sizing agent and having a weight average fiber diameter of 11 μm or less, the reflow heat resistance can be sufficiently enhanced as compared with when other fibrous reinforcing materials are used for the same semi-aromatic polyamide resin (A).

[0020] By setting the fiber diameter of the fibrous reinforcing material (C) surface-treated with the epoxy sizing agent to 11 μm or less, it is considered that when the molten polyamide resin composition is poured into a mold during molding, the shear force between the semi-aromatic polyamide resin (A) and the fibrous reinforcing material (C) per fiber can be reduced. By reducing the above shear force, it is possible to suppress the embrittlement of the interface between the semi-aromatic polyamide resin (A) and the fibrous reinforcing material (C). For these reasons, it is considered that the strength at the interface (interface strength) between the fibrous reinforcing material and the semi-aromatic polyamide resin (A) can be sufficiently increased, the generation of blisters starting from the above interface can be sufficiently suppressed, and the above reflow heat resistance can be sufficiently enhanced.

[0021] 1-1. Semi-aromatic polyamide resin (A) The semi-aromatic polyamide resin (A) is a polyamide resin having a melting point of 280°C or higher measured by a differential scanning calorimeter (DSC). The semi-aromatic polyamide resin (A) forms crystals in the molded body and can increase the mechanical strength (such as tensile strength) of the molded body. Further, since the semi-aromatic polyamide resin (A) has a high melting point, it is possible to suppress the melting of the polyamide resin in the reflow process. The method for measuring the melting point of the semi-aromatic polyamide resin (A) will be described later.

[0022] The semi-aromatic polyamide resin (A) is, for example, a polyamide resin containing a component unit (Aa) derived from a dicarboxylic acid and a component unit (Ab) derived from a diamine. Hereinafter, the semi-aromatic polyamide resin containing the component unit (Aa) derived from a dicarboxylic acid and the component unit (Ab) derived from a diamine will be described.

[0023] (Component unit (Aa) derived from dicarboxylic acid) The component unit (Aa) derived from dicarboxylic acid preferably contains a component unit derived from aromatic dicarboxylic acid, and more preferably contains a component unit derived from terephthalic acid.

[0024] The content of the component unit derived from terephthalic acid is preferably 40 mol% or more, more preferably 50 mol% or more, and still more preferably 60 mol% or more based on the total number of moles of the component unit (Aa) derived from dicarboxylic acid. When the above content is 40 mol% or more, the aromatic ring concentration in the polyamide resin (A) increases, and the polyamide resin is likely to carbonize. As a result, the flame retardancy of the molded body is likely to increase. Also, the content of the component unit derived from terephthalic acid may be 100 mol% or less, preferably 75 mol% or less, more preferably 70 mol% or less, and still more preferably 65 mol% or less based on the total number of moles of the component unit (Aa) derived from dicarboxylic acid. By setting the above content to 75 mol% or less, the melt viscosity of the polyamide resin composition can be appropriately reduced. As a result, when the melted polyamide resin composition is poured into a mold during molding, the shear generated between the semi-aromatic polyamide resin (A) and the fibrous reinforcing material (C) can be made smaller, and the strength at the interface between them can be more sufficiently increased. Therefore, the reflow heat resistance of the molded body can be more sufficiently increased.

[0025] The component unit (Aa) derived from dicarboxylic acid may contain a component unit derived from other dicarboxylic acids. Examples of other dicarboxylic acids include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids other than terephthalic acid. Among these, aliphatic dicarboxylic acids are preferred.

[0026] Examples of the aliphatic dicarboxylic acid include aliphatic dicarboxylic acids having 4 to 20 carbon atoms. The number of carbon atoms is preferably 6 to 12. Examples of such aliphatic dicarboxylic acids include adipic acid, azelaic acid, and sebacic acid. Among these, adipic acid and sebacic acid are preferred, and adipic acid is more preferred.

[0027] The content of the component unit derived from the aliphatic dicarboxylic acid is preferably 0 mol% or more and 60 mol% or less, more preferably 30 mol% or more and 60 mol% or less, still more preferably 30 mol% or more and 45 mol% or less, and particularly preferably 35 mol% or more and 45 mol% or less with respect to the total number of moles of the component unit (Aa) derived from the dicarboxylic acid.

[0028] Examples of the alicyclic dicarboxylic acid include cyclohexanedicarboxylic acid and its esters.

[0029] Examples of aromatic dicarboxylic acids other than terephthalic acid include isophthalic acid, 2-methylterephthalic acid, and naphthalenedicarboxylic acid.

[0030] The content of the component unit derived from the alicyclic dicarboxylic acid and the aromatic dicarboxylic acid other than terephthalic acid is preferably 20 mol% or more and 80 mol% or less, and more preferably 25 mol% or more and 75 mol% or less with respect to the total number of moles of the component unit (Aa) derived from the dicarboxylic acid.

[0031] (Component unit (Ab) derived from diamine) The component unit (Ab) derived from diamine includes, for example, a component unit derived from an aliphatic diamine having 4 to 15 carbon atoms, a component unit derived from an alicyclic diamine having 4 to 20 carbon atoms, and a component unit derived from an aromatic diamine.

[0032] The number of carbon atoms of the above aliphatic diamine is preferably 4 or more and 12 or less, more preferably 6 or more and 12 or less. Examples of the above aliphatic diamine include linear alkylene diamine and branched alkylene diamine.

[0033] Examples of the above linear alkylene diamine include 1,4-diaminobutane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12-diaminododecane and the like. Among these, 1,6-diaminohexane, 1,9-nonanediamine and 1,10-diaminodecane are preferable, and 1,6-diaminohexane is more preferable. The linear alkylene diamine may be contained alone or in combination of two or more.

[0034] Examples of the branched-chain alkylene diamine include 2,2-dimethyldiaminopropane, 1,1-dimethyl-1,4-diaminobutane, 1-ethyl-1,4-diaminobutane, 1,2-dimethyl-1,4-diaminobutane, 1,3-dimethyl-1,4-diaminobutane, 1,4-dimethyl-1,4-diaminobutane, 2,3-dimethyl-1,4-diaminobutane, 2-methyl-1,5-diaminopentane, 2,5-dimethyl-1,6-diaminohexane, 2,4-dimethyl-1,6-diaminohexane, 3,3-dimethyl-1,6-diaminohexane, 2,2-dimethyl-1,6-diaminohexane, 2,2,4-trimethyl-1,6-diaminohexane, 2,4,4-trimethyl-1,6-diaminohexane, 2,4-diethyl-1,6-diaminohexane, 2,3-dimethyl-1,7-diaminoheptane, 2,4-dimethyl-1,7-diaminoheptane, 2,5-dimethyl-1,7-diaminoheptane, 2,2-dimethyl-1,7-diaminoheptane, 2-methyl-4-ethyl-1,7-diaminoheptane, 2-ethyl-4-methyl-1,7-diaminoheptane, 2,2,5,5-tetramethyl-1,7-diaminoheptane, 3-isopropyl-1,7-diaminoheptane, 3-isooctyl-1,7-diaminoheptane, 2-methyl-1,8-diaminooctane, 1,3-dimethyl-1,8-diaminooctane, 1,4-dimethyl-1,8-diaminooctane, 2,4-dimethyl-1,8-diaminooctane, 3,4-dimethyl-1,8-diaminooctane, 4,5-dimethyl-1,8-diaminooctane, 2,2-dimethyl-1,8-diaminooctane, 3,3-dimethyl-1,8-diaminooctane, 4,4-dimethyl-1,8-diaminooctane, 3,3,5-trimethyl-1,8-diaminooctane, 2,4-diethyl-1,8-diaminooctane, and 5-methyl-1,9-diaminononane. Among these, 2-methyl-1,5-diaminopentane is preferred.

[0035] The content of the component unit derived from the aliphatic diamine is preferably 30 mol% or more and 100 mol% or less, more preferably 70 mol% or more and 100 mol% or less, based on the total number of moles of the component unit (Ab) derived from the diamine.

[0036] Examples of the alicyclic diamine having 4 to 20 carbon atoms include 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 2,5-bisaminomethylnorbornane, and 2,6-bisaminomethylnorbornane. Examples of the aromatic diamine include metaxylylenediamine.

[0037] Each constitutional unit and its ratio of the semi-aromatic polyamide resin (A) can be calculated from the charging ratio during the preparation of the semi-aromatic polyamide resin (A) or can be measured by the NMR method.

[0038] 1 In the case of 1H-NMR measurement, for example, a nuclear magnetic resonance apparatus (ECX400 type manufactured by JEOL Ltd.) is used, the solvent is deuterated orthodichlorobenzene, the sample concentration is 20 mg / 0.6 mL, the measurement temperature is 120 °C, and the observed nucleus is 1 1H (400 MHz), the sequence is a single pulse, the pulse width is 5.12 μs (45° pulse), the repetition time is 7.0 s, and the number of integration times is 500 times or more. The reference chemical shift is set such that the hydrogen of tetramethylsilane is 0 ppm. However, the same result can also be obtained by setting the peak derived from the residual hydrogen of deuterated orthodichlorobenzene to 7.10 ppm as the reference value of the chemical shift. The 1 peaks such as 1H derived from the functional group-containing compound can be assigned by a conventional method.

[0039] 13 In the case of 13C-NMR measurement, for example, a nuclear magnetic resonance apparatus (ECP500 type manufactured by JEOL Ltd.) is used as the measurement apparatus, an orthodichlorobenzene / deuterated benzene (80 / 20 vol%) mixed solvent is used as the solvent, the measurement temperature is 120 °C, and the observed nucleus is 13C (125 MHz), single pulse proton decoupling, 45° pulse, repetition time of 5.5 seconds, number of accumulations of 10,000 or more, with 27.50 ppm as the reference value of chemical shift. The assignment of various signals is carried out based on the conventional method, and quantification can be carried out based on the integrated value of signal intensity.

[0040] Note that the component unit derived from the dicarboxylic acid of the semi-aromatic polyamide resin (A) may contain a component unit derived from a biomass-derived dicarboxylic acid, and the component unit derived from the diamine may contain a component unit derived from a biomass-derived diamine. Further, the semi-aromatic polyamide resin (A) may be a biomass-derived semi-aromatic polyamide resin (A) obtained by polymerizing a raw material group containing a biomass-derived raw material.

[0041] The semi-aromatic polyamide resin (A) preferably contains a component unit (Aa) derived from a dicarboxylic acid and containing a component unit derived from terephthalic acid, and a component unit (Ab) derived from a diamine and containing a component unit derived from 1,6-diaminohexane. At this time, the content of the component unit derived from 1,6-diaminohexane is preferably 70 mol% or more and 100 mol% or less, more preferably 80 mol% or more and 100 mol% or less, based on the total number of moles of the component unit (Ab) derived from the diamine. Thereby, the crystallinity of the semi-aromatic polyamide resin (A) can be further increased. As a result, the molecular chain movement at high temperature can be suppressed, so that the deformation of the molded body during the reflow process can be suppressed, and the generation of blisters due to the vaporization of moisture inside the molded body can be more sufficiently suppressed. That is, the reflow heat resistance can be more sufficiently enhanced.

[0042] Specific examples of the semi-aromatic polyamide resin (A) include polyamide 6T6I, polyamide 6T66, polyamide 6TDT, etc. Among these, polyamide 6T6I and polyamide 6T66 are preferred, and polyamide 6T66 is more preferred.

[0043] The semi-aromatic polyamide resin (A) can be produced in the same manner as known polyamide resins. For example, it can be produced by polycondensing a dicarboxylic acid and a diamine in a homogeneous solution. Specifically, a lower condensate can be obtained by heating a dicarboxylic acid and a diamine in the presence of a catalyst as described in WO 03 / 085029, and then polycondensing by applying a shear stress to the melt of this lower condensate.

[0044] The content of the semi-aromatic polyamide resin (A) is preferably 20% by mass or more and 70% by mass or less, more preferably 30% by mass or more and 60% by mass or less, and even more preferably 35% by mass or more and 55% by mass or less, based on the total mass of the polyamide resin composition. When the above content is 20% by mass or more, the mechanical strength of the polyamide resin composition can be increased. When the above content is 70% by mass or less, other components described later can be sufficiently included in the polyamide resin composition.

[0045] (Physical properties) From the viewpoint of further enhancing the mechanical strength of the molded article, the melting point of the semi-aromatic polyamide resin (A) is 280°C or higher, preferably 290°C or higher, and more preferably 300°C or higher. Also, from the viewpoint of suppressing the decomposition of the amide bond of the semi-aromatic polyamide resin (A), the melting point of the semi-aromatic polyamide resin (A) is preferably 340°C or lower.

[0046] The melting point of the semi-aromatic polyamide resin (A) can be adjusted to the above range by adjusting the composition of the semi-aromatic polyamide resin (A). For example, the melting point can be increased by increasing the content ratio of the component unit derived from terephthalic acid described later.

[0047] Further, the semi-aromatic polyamide resin (A) preferably has a glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) of more than 70°C and 145°C or less, more preferably 75°C or more and 125°C or less, and even more preferably 80°C or more and 100°C or less. When the glass transition temperature (Tg) is 70°C or higher, the temperature at which the molecular mobility becomes active in a high-temperature environment increases, so that the molecular mobility can be suppressed to further enhance the heat resistance of the polyamide resin composition and the molded article. Further, when the glass transition temperature (Tg) is 145°C or lower, the fluidity of the polyamide resin composition can be easily maintained without excessively increasing the mold temperature during the molding process, and the molding processability can be improved.

[0048] The heat of fusion (ΔH) measured by differential scanning calorimetry (DSC) of the semi-aromatic polyamide resin (A) is preferably more than 5 J / g. The heat of fusion is an index of the crystallinity of the resin, and the larger the heat of fusion, the higher the crystallinity. When the heat of fusion (ΔH) of the semi-aromatic polyamide resin (A) exceeds 5 J / g, the crystallinity increases, so that the mechanical strength (such as flexural strength) of the obtained molded article can be enhanced.

[0049] The melting point and the heat of fusion (ΔH) of the semi-aromatic polyamide resin (A) can be measured using a differential scanning calorimeter (DSC220C type, manufactured by Seiko Instruments Inc.).

[0050] Specifically, about 5 mg of the semi-aromatic polyamide resin (A1) is sealed in a measurement aluminum pan and heated from room temperature to 350°C at 10°C / min. In order to completely melt the resin, it is held at 350°C for 3 minutes, and then cooled to 30°C at 10°C / min. After leaving it at 30°C for 5 minutes, the second heating is performed from 30°C to 350°C at 10°C / min. The temperature (°C) of the endothermic peak in this second heating is defined as the melting point (Tm) of the semi-aromatic polyamide resin (A), and the inflection point corresponding to the glass transition is defined as the glass transition temperature (Tg). The heat of fusion (ΔH) is determined from the area of the endothermic peak during melting in the first heating process in accordance with JIS K7122.

[0051] The intrinsic viscosity [η] of the semi-aromatic polyamide resin (A), measured in 96.5% sulfuric acid at 25°C, is preferably 0.9 dl / g or more and 1.2 dl / g or less, more preferably 1.0 dl / g or more and 1.2 dl / g or less, and particularly preferably 1.0 dl / g or more and 1.1 dl / g or less. When the intrinsic viscosity [η] of the semi-aromatic polyamide resin (A) is 0.9 dl / g or more, it is easy to sufficiently increase the mechanical strength (such as flexural strength) of the molded article, and when it is 1.2 dl / g or less, the fluidity during molding of the resin composition is hardly impaired. The intrinsic viscosity [η] can be adjusted by adjusting the molar ratio of the component unit (Aa) derived from dicarboxylic acid and the component unit (Ab) derived from diamine. Specifically, the closer the molar ratio of the component unit (Aa) derived from carboxylic acid and the component unit (Ab) derived from diamine is to 1:1, the higher the intrinsic viscosity can be increased. It can also be adjusted by the amount of end capping of the semi-aromatic polyamide resin (A), etc.

[0052] The intrinsic viscosity [η] of the semi-aromatic polyamide resin (A) can be measured as follows. Dissolve 0.5 g of the semi-aromatic polyamide resin (A) in 50 ml of a 96.5% sulfuric acid solution to obtain a sample solution. Measure the flow-down seconds of the obtained solution under the condition of 25°C ± 0.05°C using an Ubbelohde viscometer, and calculate based on the following formula. [η]=ηSP / (C*(1 + 0.205ηSP)) [η]: Intrinsic viscosity (dl / g) ηSP: Specific viscosity C: Sample concentration (g / dl) t: Flow-down seconds of the sample solution (seconds) t0: Flow-down seconds of blank sulfuric acid (seconds) ηSP=(t - t0) / t0

[0053] The amount of terminal carboxyl groups in the semi-aromatic polyamide resin (A) is preferably 20 mmol / kg or more and 200 mmol / kg or less, more preferably 40 mmol / kg or more and 170 mmol / kg or less. When the amount of the terminal carboxyl groups is 200 mmol / kg or less, the generation of blisters can be further suppressed, and the reflow heat resistance can be more sufficiently enhanced. The terminal carboxyl groups can act as an autocatalyst during thermal decomposition. Although it is considered that the polyamide resin thermally decomposes due to local heat generation caused by shear during molding, the decrease in molecular weight due to thermal decomposition can be suppressed because the amount of terminal carboxyl groups that can act as an autocatalyst is low. Thereby, the decrease in the mechanical strength of the molded body can be further suppressed, and the generation of blisters can be further suppressed.

[0054] The amount of the terminal carboxyl groups can be measured, for example, using the NMR method. Specifically, for example, 30 mg of the polyamide resin is dissolved in 0.5 mL of deuterated hexafluoroisopropanol (HFIP) to prepare a sample for NMR measurement. NMR measurement is performed on the prepared sample using a nuclear magnetic resonance apparatus (ECA-500 type, manufactured by JEOL Ltd.). The molecular weight of the polyamide resin is calculated from the peak areas of hydrogen derived from each component constituting the polyamide resin in the obtained spectrum, and the amount of terminal carboxyl groups ([COOH], unit: mmol / kg) is calculated using the peak area of hydrogen specific to the terminal carboxyl groups and the value of the molecular weight.

[0055] Also, the amount of terminal amino groups in the semi-aromatic polyamide resin (A) is preferably 30 mmol / kg or more and 200 mmol / kg or less, more preferably 50 mmol / kg or more and 200 mmol / kg or less, and still more preferably 50 mmol / kg or more and 150 mmol / kg or less. When the amount of the terminal amino groups is 30 mmol / kg or more, the thermal decomposition of the polyamide resin caused by shear heat generation during compounding or injection molding can be suppressed, so that the reflow heat resistance can be more sufficiently enhanced. For the same reason, when the amount of the terminal amino groups is 50 mmol / kg or more, the reflow heat resistance can be further enhanced. The amount of the terminal amino groups can be measured, for example, by the following method.

[0056] Dissolve 1 g of the polyamide resin in 35 mL of phenol, mix 2 mL of methanol therewith to obtain a sample solution. Using thymol blue as an indicator, titrate the sample solution with a 0.01 N hydrochloric acid aqueous solution using a potentiometric titrator (manufactured by Metrohm) until the color changes from blue to yellow, and measure the amount of terminal amino groups ([NH2], unit: mmol / kg).

[0057] 1-2. Flame retardant (B) In the present embodiment, the polyamide resin composition contains a flame retardant (B) which is a halogen-containing compound. The flame retardant (B) can impart flame retardancy to the polyamide resin composition and its molded article.

[0058] Examples of the halogen-containing compound include brominated polystyrene, polybrominated styrene, brominated polyphenylene ether, and the like. Among these, the halogen-containing compound is preferably brominated polystyrene or polybrominated styrene, and more preferably brominated polystyrene.

[0059] The content of the flame retardant (B) is preferably 10% by mass or more and 50% by mass or less, and more preferably 15% by mass or more and 45% by mass or less with respect to the total mass of the polyamide resin composition. When the above content is 10% by mass or more, the flame retardancy of the polyamide resin composition and its molded article can be further enhanced. Further, when the above content is 50% by mass or less, the reflow heat resistance of the polyamide resin composition and its molded article can be more sufficiently enhanced.

[0060] 1-3. Fibrous reinforcing material (C) In the present embodiment, the polyamide resin composition contains a fibrous reinforcing material (C) surface-treated with an epoxy-based sizing agent. In this specification, the "epoxy-based sizing agent" means a sizing agent containing a compound containing an epoxy group.

[0061] The type of the fibrous reinforcing material (C) is not particularly limited. For example, it includes glass fiber, carbon fiber, wollastonite, potassium titanate whisker, calcium carbonate whisker, aluminum borate whisker, magnesium sulfate whisker, sepiolite, zonnolite, zinc oxide whisker, milled fiber, cut fiber, boron fiber, liquid crystal polyester fiber, and the like. Among these, since glass fiber has particularly low affinity with the semi-aromatic polyamide resin (A), the interfacial strength is remarkably improved by surface treatment with an epoxy sizing agent. That is, the reflow heat resistance of the molded body is remarkably improved.

[0062] Examples of the epoxy compound contained in the epoxy-based sizing agent include glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, glycidyl itaconate, and glycidyl citraconate.

[0063] The adhesion amount of the epoxy-based sizing agent is preferably 0.1 part by mass or more and 1 part by mass or less, more preferably 0.2 part by mass or more and 0.8 part by mass or less with respect to 100 parts by mass of the fibrous reinforcing material (C). When the adhesion amount is 0.2 part by mass or more, the affinity between the semi-aromatic polyamide resin (A) and the fibrous reinforcing material (C) can be further enhanced, and the reflow heat resistance of the polyamide resin composition and its molded body can be more sufficiently enhanced. Also, when it is 1 part by mass or less, a decrease in reflow heat resistance due to decomposition of the epoxy-based sizing agent can be suppressed.

[0064] The adhesion amount of the organic substance can be determined as the loss on ignition. The loss on ignition can be measured by the mass loss in the loss on ignition test conforming to JIS K 0067 (1992). Specifically, it can be calculated from the mass of the fibrous reinforcing material (C) before and after heat treatment by heating the fibrous reinforcing material (C) at 620 °C for 1 hour to incinerate and remove the non-volatile components. The loss on ignition is obtained as (x - y) / x × 100, where x is the mass of the glass fiber before heat treatment and y is the mass of the fibrous reinforcing material (C) after heat treatment.

[0065] The weight-average fiber diameter (Dw) of the fibrous reinforcing material (C) is 11.0 μm or less, preferably 10.8 μm or less, and more preferably 10.5 μm or less. When the weight-average fiber diameter (Dw) is 10.8 μm or less, the shear force between the semi-aromatic polyamide resin (A) and the fibrous reinforcing material (C) per fiber generated when the molten polyamide resin composition is poured into a mold can be made smaller. Thereby, the strength at the interface between the semi-aromatic polyamide resin (A) and the fibrous reinforcing material can be more sufficiently increased, and the reflow heat resistance of the molded body can be more sufficiently increased. The lower limit value of the weight-average fiber diameter (Dw) is not particularly limited, but is, for example, 3 μm. In this specification, the "fiber diameter" refers to the length of the longest line segment among the line segments connecting opposite edges in the cross section of the fibrous reinforcing material.

[0066] The weight-average fiber length (Lw) of the fibrous reinforcing material (C) is, for example, 10 μm or more and 3000 μm or less, and preferably 100 μm or more and 1000 μm or less.

[0067] The weight-average fiber diameter (Dw) and the weight-average fiber length (Lw) of the fibrous reinforcing material (C) can be measured by the following method. 1) After dissolving the polyamide resin composition in a hexafluoroisopropanol / chloroform solution (0.1 / 0.9% by volume), a filtrate obtained by filtration is collected. 2) The filtrate obtained in 1) above is dispersed in water, and the fiber diameter (di) and the fiber length (Li) of any 300 fibers each are measured with an optical microscope (magnification: 50 times). Let the number of fibers with a fiber diameter of Di be Ri, and the weight-average diameter (Dw) is calculated based on the following formula. Weight-average diameter (Dw) = (ΣRi × Di 2 ) / (ΣRi × Di) Similarly, let the number of fibers with a fiber length of Li be qi, and the weight-average fiber length (Lw) is calculated based on the following formula. Weight-average length (Lw) = (Σqi × Li 2 ) / (Σqi × Li)

[0068] The fibrous reinforcing material (C) preferably has an aspect ratio of less than 1.5 in cross-section. When the molten polyamide resin composition is poured into a mold during molding, the fibrous reinforcing material (C) is oriented along the flow direction of the polyamide resin composition. At this time, since the fibrous reinforcing material (C) having an aspect ratio of less than 1.5 has a short length in the direction perpendicular to the flow direction, it is considered that a path for the moisture contained in the molded body to move is easily formed inside the molded body. As a result, the moisture easily moves to the outside of the molded body, and the amount of moisture contained in the molded body decreases during the reflow process, so it is considered that blisters are less likely to occur. From such a viewpoint, the aspect ratio is more preferably 1.3 or less. The lower limit value of the aspect ratio is not particularly limited, but is, for example, 1.0. In the present specification, the "aspect ratio" means the value of the first line segment / the second line segment when a line segment passing through the center of the cross-section of the fibrous reinforcing material and connecting opposite edges in the cross-section is defined as the first line segment, and a line segment perpendicular to the longest line segment is defined as the second line segment.

[0069] The cross-sectional shape of the fibrous reinforcing material (C) is, for example, an elliptical shape and a circular shape, and a circular shape is preferable. The cross-sectional shape can be confirmed by observing with an optical microscope.

[0070] The aspect ratio can be obtained by calculating the ratio (Dw / dw) using the weight average fiber diameter (Dw) obtained by the above-described method and the weight average minor axis diameter (dw) obtained by the following method. 1) After dissolving the polyamide resin composition in a hexafluoroisopropanol / chloroform solution (0.1 / 0.9% by volume), a filtrate obtained by filtration is collected. 2) Disperse the filtrate obtained in 1) above in water, and measure the respective minor axis diameters (di) of any 300 fibers with an optical microscope (magnification: 50 times). Let the number of fibers having a minor axis diameter of di be ri, and calculate the weight average diameter (dw) based on the following formula. Here, the minor axis diameter refers to the second line segment. Weight average minor axis diameter (dw) = (Σri × di 2) / (Σri×di)

[0071] The content of the fibrous reinforcing material (C) is preferably 20% by mass or more and 40% by mass or less, more preferably 25% by mass or more and 35% by mass or less, based on the total mass of the polyamide resin composition. When the content is 20% by mass or more, the strength of the molded article of the polyamide resin composition can be further increased. When the content is 40% by mass or less, the total contact area between the semi-aromatic polyamide resin (A) and the fibrous reinforcing material (C) can be reduced. Thereby, the area of the interface between the fibrous reinforcing material (C) and the semi-aromatic polyamide resin (A) can be reduced, so that the generation of blisters starting from the above interface can be more suppressed. That is, when the content is 40% by mass or less, the reflow heat resistance of the polyamide resin composition and its molded article can be more sufficiently enhanced.

[0072] 1-4. Other components The polyamide resin composition may contain other known components.

[0073] Examples of other components include flame retardant aids, nucleating agents, lubricants, drip preventers, halogen scavengers, other flame retardants, other polyamide resins, polyolefin resins, colorants, heat stabilizers, corrosion resistance improvers, ion scavengers, elastomers (rubbers), antistatic agents, mold release agents, antioxidants (such as phenols, amines, sulfurs, and phosphorus), heat stabilizers other than the above (such as lactone compounds, vitamin E, and hydroquinones), and light stabilizers (such as benzotriazoles, triazines, benzophenones, benzoates, hindered amines, and oxanilides).

[0074] (Flame retardant aid) The flame retardant aid may be any substance that can enhance the flame retardant effect of the flame retardant, and known substances can be used. Specific examples of the flame retardant aid include antimony compounds such as antimony trioxide, antimony tetroxide, antimony pentoxide, and sodium antimonate; zinc compounds such as zinc borate, zinc stannate, and zinc phosphate; calcium borate, calcium molybdate, etc. These may be used alone or in combination of two or more. Among these, sodium antimonate, zinc borate, and zinc phosphate are preferred, and anhydrides of sodium antimonate and zinc borate (2ZnO·3B2O3) are particularly preferred from the viewpoint of thermal stability.

[0075] The content of the flame retardant aid is preferably 0.5% by mass or more and 5.0% by mass or less, more preferably 1.0% by mass or more and 3.0% by mass or less, based on the total mass of the polyamide resin composition.

[0076] (Nucleating agent) The nucleating agent can promote the crystallization of the semi-aromatic polyamide resin (A). Therefore, the tensile strength and elastic modulus of the resin member can be further increased.

[0077] Examples of the nucleating agent include metal salt-based compounds containing sodium 2,2-methylenebis(4,6-di-t-butylphenyl) phosphate, aluminum tris(p-t-butylbenzoate), and stearates; sorbitol-based compounds containing bis(p-methylbenzylidene)sorbitol and bis(4-ethylbenzylidene)sorbitol; and inorganic substances containing talc, calcium carbonate, and hydrotalcite. Among these, talc is preferred from the viewpoint of further increasing the crystallinity of the resin member. These nucleating agents may be used alone or in combination of two or more.

[0078] Talc generally contains hydrated magnesium silicate (SiO2: 58 - 64%, MgO: 28 - 32%, Al2O3: 0.5 - 5%, Fe2O3: 0.3 - 5%) as the main component. The average particle size of talc is not particularly limited, but is preferably 1 - 15 μm. When the average particle size of talc is within the above range, it is easy to disperse talc in the polyamide resin (A) without impairing the fluidity of the polyamide resin composition. From the same viewpoint, the average particle size of talc is more preferably 1 - 7.5 μm. The average particle size of talc can be measured by a laser diffraction method, for example, a laser diffraction method using a Shimadzu particle size distribution analyzer (SALD - 2000A type) manufactured by Shimadzu Corporation.

[0079] The content of the nucleating agent is preferably 0.10 parts by mass or more and 5.00 parts by mass or less, and more preferably 0.10 parts by mass or more and 3.00 parts by mass or less based on the total mass of the polyamide resin composition. When the content of the nucleating agent is within the above range, it is easy to sufficiently increase the crystallinity of the resin member, and sufficient mechanical strength is easily obtained.

[0080] (Lubricant) The lubricant improves the injection fluidity of the polyamide resin composition and improves the appearance of the resulting resin member. The lubricant can be a fatty acid metal salt such as a metal oxycarboxylate and a higher fatty acid metal salt.

[0081] The oxycarboxylic acid constituting the above metal oxycarboxylate may be an aliphatic oxycarboxylic acid or an aromatic oxycarboxylic acid. Examples of the above aliphatic oxycarboxylic acids include aliphatic oxycarboxylic acids having 10 to 30 carbon atoms such as α-hydroxymyristic acid, α-hydroxypalmitic acid, α-hydroxystearic acid, α-hydroxyeicosanoic acid, α-hydroxydocosanoic acid, α-hydroxytetraeicosanoic acid, α-hydroxyhexaicosanoic acid, α-hydroxyoctaicosanoic acid, α-hydroxytriacontanoic acid, β-hydroxymyristic acid, 10-hydroxydecanoic acid, 15-hydroxypentadecanoic acid, 16-hydroxyhexadecanoic acid, 12-hydroxystearic acid, and ricinoleic acid. Examples of the above aromatic oxycarboxylic acids include salicylic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, gallic acid, mandelic acid, and tropic acid, etc.

[0082] Examples of the metal constituting the above metal oxycarboxylate include alkali metals such as lithium, and alkaline earth metals such as magnesium, calcium, and barium.

[0083] Among these, the above metal oxycarboxylate is preferably a metal salt of 12-hydroxystearic acid, and more preferably magnesium 12-hydroxystearate and calcium 12-hydroxystearate.

[0084] Examples of the higher fatty acid constituting the above higher fatty acid metal salt include higher fatty acids having 15 to 30 carbon atoms such as stearic acid, oleic acid, behenic acid, behenic acid, and montanic acid.

[0085] Examples of the metal constituting the above higher fatty acid metal salt include calcium, magnesium, barium, lithium, aluminum, zinc, sodium, and potassium, etc.

[0086] Among these, the above-mentioned metal salts of higher fatty acids are preferably calcium stearate, magnesium stearate, barium stearate, calcium behenate, sodium montanate, and calcium montanate.

[0087] The content of the lubricant is preferably 0.01% by mass or more and 1.30% by mass or less based on the total mass of the polyamide resin composition. When the content of the lubricant is 0.01% by mass or more, the fluidity during molding is likely to increase, and the appearance of the resulting molded product is likely to improve. When the content of the lubricant is 1.30% by mass or less, gas generated by the decomposition of the lubricant is less likely to be generated during molding, and the appearance of the product is likely to be good.

[0088] (Drip inhibitor) The drip inhibitor is an additive for suppressing the dripping of resin droplets in the combustion test of the molded body of the polyamide resin composition (for example, the test of UL94 standard (1991)). Examples of the drip inhibitor include maleic acid-modified styrene-ethylene-butylene-styrene (SEBS) copolymer, fluororesin, and the like.

[0089] (Halogen scavenger) The halogen scavenger is preferably contained in the polyamide resin composition when a halogen-containing compound is used as the above-mentioned flame retardant. The halogen scavenger can capture halide ions generated when a molded body of the polyamide resin composition containing a halogen-containing compound is burned, and suppress the generation of harmful substances. Examples of the halogen scavenger include hydrotalcite and the like.

[0090] (Other flame retardants) The polyamide resin composition in this embodiment may further contain other flame retardants other than the flame retardant (B). Examples of other flame retardants include phosphinate compounds and the like. Examples of the above phosphinate compounds are compounds represented by the following formulas (I) and (II).

[0091] [Chemical formula]

[0092] In formula (I) and formula (II), R 1 and R 2 are each independently a linear or branched alkyl group or aryl group having 1 to 6 carbon atoms. R 3 is a linear or branched alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 10 carbon atoms, an alkylarylene group having 6 to 10 carbon atoms, or an arylalkylene group having 6 to 10 carbon atoms. M is Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K and / or a protonated nitrogen base. m, n, and x are each independently an integer from 1 to 4.

[0093] Specific examples of the phosphinate compound include calcium dimethylphosphinate, magnesium dimethylphosphinate, aluminum dimethylphosphinate, zinc dimethylphosphinate, calcium ethylmethylphosphinate, magnesium ethylmethylphosphinate, aluminum ethylmethylphosphinate, zinc ethylmethylphosphinate, calcium diethylphosphinate, magnesium diethylphosphinate, aluminum diethylphosphinate, zinc diethylphosphinate, calcium methyl-n-propylphosphinate, magnesium methyl-n-propylphosphinate, aluminum methyl-n-propylphosphinate, zinc methyl-n-propylphosphinate, calcium methanedi(methylphosphinate), magnesium methanedi(methylphosphinate), aluminum methanedi(methylphosphinate), zinc methanedi(methylphosphinate), calcium benzene-1,4-(dimethylphosphinate), magnesium benzene-1,4-(dimethylphosphinate), aluminum benzene-1,4-(dimethylphosphinate), zinc benzene-1,4-(dimethylphosphinate), calcium methylphenylphosphinate, magnesium methylphenylphosphinate, aluminum methylphenylphosphinate, zinc methylphenylphosphinate, calcium diphenylphosphinate, magnesium diphenylphosphinate, aluminum diphenylphosphinate, zinc diphenylphosphinate, and the like. Preferably, they are calcium dimethylphosphinate, aluminum dimethylphosphinate, zinc dimethylphosphinate, calcium ethylmethylphosphinate, aluminum ethylmethylphosphinate, zinc ethylmethylphosphinate, calcium diethylphosphinate, aluminum diethylphosphinate, zinc diethylphosphinate; more preferably, it is aluminum diethylphosphinate.

[0094] (Other polyamide resins) The polyamide resin composition in this embodiment may further contain other polyamide resins other than the semi-aromatic polyamide resin (A).

[0095] Examples of other polyamide resins include polyamide resins having a heat of fusion (ΔH) measured by a differential scanning calorimeter (DSC) of 0 J / g or more and 5 J / g or less, and polyamide resins having a melting point measured by a differential scanning calorimeter (DSC) of less than 280°C.

[0096] The polyamide resin having a heat of fusion (ΔH) measured by a differential scanning calorimeter (DSC) of 0 J / g or more and 5 J / g or less is preferably an amorphous polyamide resin, and more preferably polyamide 6I6T.

[0097] 1-5. Method for producing polyamide resin composition The polyamide resin composition can be produced by mixing the above-mentioned semi-aromatic polyamide resin (A), flame retardant (B), fibrous reinforcing material (C) and other components as required by a known resin kneading method, such as a Henschel mixer, V blender, ribbon blender, or tumbler blender, or by melt-kneading with a single-screw extruder, multi-screw extruder, kneader, or Banbury mixer after mixing and then granulating or pulverizing. At this time, the melting temperature during melt-kneading is preferably 10°C or more and 20°C or less above the melting point (Tm) of the semi-aromatic polyamide resin (A).

[0098] 2. Molded article The molded article of the present invention is formed by molding the polyamide resin composition of the present invention. With the above-mentioned polyamide resin composition, the molded article has sufficiently enhanced reflow heat resistance and enhanced flame retardancy.

[0099] The above-mentioned molded article can be produced by using the above-mentioned polyamide resin composition by a normal melt molding method, such as a compression molding method or an injection molding method. For example, the polyamide resin composition of the present invention is put into an injection molding machine whose cylinder temperature is adjusted to be equal to or higher than the melting point of the polyamide resin (A), for example, about 280°C or more and 350°C or less, melted, and introduced into a mold of a predetermined shape to produce a molded article.

[0100] The shape of the molded article produced using the polyamide resin composition of the present invention is not particularly limited and can take various shapes depending on the application.

[0101] Examples of the uses of the molded article of the polyamide resin composition in the present embodiment include vehicle structural parts, vehicle-mounted articles, housings of electronic devices, housings of household electrical appliances, structural parts, machine parts, various automotive parts, parts for electronic devices, medical devices, and the like. As described above, since the polyamide resin composition can enhance the reflow heat resistance of the molded article, it can be suitably used particularly for parts for electronic devices among these uses.

Examples

[0102] Hereinafter, the present invention will be described with reference to examples. The scope of the present invention is not construed as being limited by the examples.

[0103] 1. Synthesis / Preparation of Materials 1-1. Synthesis of Polyamide Resin (A) <Polyamide Resin PA-1(6T66)> 2515 g (15.1 mol) of terephthalic acid, 2800 g (24.1 mol) of 1,6-diaminohexane, 1325 g (9.0 mol) of adipic acid, 5.7 g of sodium hypophosphite monohydrate, and 554 g of distilled water were placed in an autoclave with an internal volume of 13.6 L and purged with nitrogen. Stirring was started at 190°C, and the internal temperature was raised to 250°C over 3 hours. At this time, the internal pressure of the autoclave was increased to 3.01 MPa. After continuing the reaction for 1 hour, atmospheric discharge was performed from the spray nozzle installed at the bottom of the autoclave to extract the low-order condensate. The extracted low-order condensate was cooled to room temperature, then pulverized to a particle size of 1.5 mm or less with a pulverizer, and dried at 110°C for 24 hours.

[0104] Next, this low-order condensate was placed in a stepped solid-phase polymerization apparatus. After nitrogen substitution, the temperature was raised to 220°C over about 1 hour and 30 minutes. Then, the low-order condensate was reacted for 1 hour and the temperature was lowered to room temperature. Thereafter, in a twin-screw extruder with a screw diameter of 30 mm and L / D = 36, polyamide (high condensate) was further melt-polymerized at a barrel set temperature of 330°C, a screw rotation speed of 200 rpm, and a resin supply rate of 6 kg / hour to obtain polyamide resin PA-1.

[0105] The intrinsic viscosity [η] of the obtained polyamide resin PA-1 was 0.8 dl / g, the melting point (Tm) was 320°C, and the glass transition temperature (Tg) was 95°C. Also, the heat of fusion (ΔH) measured by a differential scanning calorimeter (DSC) was 50 J / g. Further, the composition of the obtained polyamide resin PA-1 was such that the content of the component unit derived from terephthalic acid was 62.5 mol% and the content of the component unit derived from adipic acid was 37.5 mol% with respect to the total number of moles of the component units derived from dicarboxylic acids, and the content of the component unit derived from 1,6-diaminohexane was 100 mol% with respect to the total number of moles of the component units derived from diamines. Also, the amount of terminal amino groups in the polyamide resin PA-1 was 113 mmol / kg, and the amount of terminal carboxyl groups was 52 mmol / kg.

[0106] <Preparation of Polyamide Resin PA-2 (6T6I)> 2800 g (24.1 mol) of 1,6-diaminohexane, 2774 g (16.7 mol) of terephthalic acid, 1196 g (7.2 mol) of isophthalic acid, 5.7 g (5.4×10 -236.6 g (0.30 mol) of benzoic acid as a molecular weight regulator and 545 g of distilled water were placed in an autoclave with an internal volume of 13.6 L and purged with nitrogen. Stirring was started at 190°C, and the internal temperature was raised to 250°C over 3 hours. At this time, the internal pressure of the autoclave was increased to 3.03 MPa. After continuing the reaction for 1 hour, the low-order condensate was extracted by discharging to the atmosphere from the spray nozzle installed at the bottom of the autoclave. Then, after cooling the low-order condensate to room temperature, it was pulverized with a pulverizer to a particle size of 1.5 mm or less and dried at 110°C for 24 hours. The water content of the obtained low-order condensate was 4100 ppm, and the intrinsic viscosity [η] was 0.15 dl / g.

[0107] Next, this low-order condensate was placed in a staged solid-phase polymerization apparatus, purged with nitrogen, and then heated to 180°C over about 1 hour 30 minutes. Then, it was reacted for 1 hour 30 minutes and cooled to room temperature. The intrinsic viscosity [η] of the obtained prepolymer was 0.20 dl / g.

[0108] After that, the obtained prepolymer was melt-polymerized in a twin-screw extruder with a screw diameter of 30 mm and L / D = 36 at a barrel set temperature of 330°C, a screw rotation speed of 200 rpm, and a resin supply rate of 6 kg / h to obtain a polyamide resin PA-2.

[0109] The intrinsic viscosity [η] of the obtained polyamide resin PA-2 was 1.00 dl / g, the melting point (Tm) was 330°C, the glass transition temperature (Tg) was 125°C, and the heat of fusion (ΔH) was 50 J / g. Also, the composition of the obtained polyamide resin PA-1 was such that the content of the component unit derived from terephthalic acid in the component unit derived from dicarboxylic acid was 70 mol%, the content of the component unit derived from isophthalic acid was 30 mol%, and the content of the component unit derived from 1,6-diaminohexane in the component unit derived from diamine was 100 mol%. Also, the amount of terminal amino groups of the polyamide resin PA-2 was 33 mmol / kg, and the amount of terminal carboxyl groups was 160 mmol / kg.

[0110] 1-2. Flame Retardant (B) Brominated polystyrene (HP-3010, manufactured by Albemarle Corporation) was used.

[0111] 1-3. Fibrous reinforcing material (C) C-1: Glass fiber (ECS03T-747H, manufactured by Nippon Electric Glass Co., Ltd., sizing agent: epoxy-based, weight average fiber diameter (Dw): 10.5 μm, aspect ratio: 1.0) C-2: Glass fiber (ECS03-615, manufactured by Central Glass Fiber Co., Ltd., sizing agent: urethane-based, weight average fiber diameter (Dw): 9.0 μm, aspect ratio: 1.0) C-3: Glass fiber (ECS03T-251H, manufactured by Nippon Electric Glass Co., Ltd., sizing agent: urethane + acid, weight average fiber diameter (Dw): 10.0 μm, aspect ratio: 1.0) C-4: Glass fiber (ECS03T-747, manufactured by Nippon Electric Glass Co., Ltd., sizing agent: epoxy-based, weight average fiber diameter (Dw): 13.0 μm, aspect ratio: 1.0)

[0112] 1-4. Other components 1-4-1. Flame retardant aid Sodium antimonate (manufactured by Nippon Mining & Metals Co., Ltd., SA-A) was used.

[0113] 1-4-2. Nucleating agent Talc (average particle size 6 μm) was used.

[0114] 1-4-3. Lubricant Calcium montanate (manufactured by Clariant Japan Ltd., Licomont CAV102) was used.

[0115] 1-4-4. Drip inhibitor m-SEBS (Tuftec M1913, maleated SEBS, manufactured by Asahi Chemical Industry Co., Ltd.) was used.

[0116] 1-4-5. Halogen scavenger Hydrotalcite (manufactured by Toda Kogyo Corporation, NAOX-33) was used.

[0117] 2. Measurement The physical properties of each of the above resins were measured by the following methods.

[0118] <Melting point (Tm), glass transition temperature (Tg)> The melting point (Tm) and glass transition temperature (Tg) of the polyamide resin were measured using differential scanning calorimetry (DSC220C type, manufactured by Seiko Instruments Inc.). Specifically, about 5 mg of the polyamide resin was sealed in a measurement aluminum pan and set for differential scanning calorimetry. Then, it was heated from room temperature to 350 °C at 10 °C / min. In order to completely melt the resin, it was held at 350 °C for 3 minutes, and then cooled to 30 °C at 10 °C / min. After leaving it at 30 °C for 5 minutes, the second heating was carried out from 30 °C to 350 °C at 10 °C / min. The temperature (°C) of the endothermic peak in this second heating was taken as the melting point (Tm) of the polyamide resin, and the inflection point corresponding to the glass transition was taken as the glass transition temperature (Tg).

[0119] <Heat of fusion (ΔH)> The heat of fusion (ΔH) of the polyamide resin was determined from the area of the exothermic peak of crystallization in the first heating process in accordance with JIS K 7122 (2012).

[0120] <Limiting viscosity [η]> The limiting viscosity [η] of the polyamide resin was measured by dissolving 0.5 g of the polyamide resin in 50 ml of a 96.5% sulfuric acid solution, measuring the flow-down seconds of the obtained solution under the condition of 25 °C ± 0.05 °C using an Ubbelohde viscometer, and calculating based on the formula: [η]=ηSP / (C(1 + 0.205ηSP)). [η]: Limiting viscosity (dl / g) ηSP: Specific viscosity C: Sample concentration (g / dl) t: Flow-down seconds of the sample solution (seconds) t0: Flow-down seconds of the blank sulfuric acid (seconds) ηSP=(t - t0) / t0

[0121] <Amount of terminal carboxyl groups> 30 mg of polyamide resin was dissolved in 0.5 mL of deuterated hexafluoroisopropanol (HFIP) to prepare a sample for NMR measurement. For the above sample, NMR measurement was performed using a nuclear magnetic resonance apparatus (ECA-500 type, JEOL Ltd.), and the molecular weight of the polymer was calculated from the peak areas of hydrogen derived from each component constituting the polyamide resin in the obtained spectrum. Then, using the peak area of hydrogen specific to the terminal carboxyl group and the value of the molecular weight obtained above, the amount of terminal carboxyl group ([COOH], unit: mmol / kg or less) was calculated.

[0122] <Amount of terminal amino group> 1 g of polyamide resin was dissolved in 35 mL of phenol and 2 mL of methanol was mixed to prepare a sample solution. Using thymol blue as an indicator, a 0.01 N hydrochloric acid aqueous solution was titrated against the sample solution using a potentiometric titrator (manufactured by Metrohm) until the color changed from blue to yellow, and the amount of terminal amino group ([NH2], unit: mmol / kg) was measured.

[0123] <Weight average fiber diameter (Dw) and aspect ratio of fibrous reinforcing material (C)> The weight average fiber diameter (Dw) and aspect ratio of the fibrous reinforcing material (C) were determined by the following procedure. 1) The polyamide resin composition was dissolved in a hexafluoroisopropanol / chloroform solution (0.1 / 0.9 vol%), and the filtrate obtained by filtration was collected. 2) The filtrate obtained in 1) above was dispersed in water, and the fiber diameters of 300 arbitrary fibers were measured using an optical microscope (magnification: 50 times). Let the number of fibers with a fiber diameter of Di be Ri, and the weight average fiber diameter (Dw) was calculated based on the following formula. Here, the length of the longest line segment connecting opposite edges in the cross-section of the fibrous reinforcing material was defined as the fiber diameter Di. Weight average fiber diameter (Dw) = (ΣRi × Di 2 ) / (ΣRi × Di)

[0124] Similarly, measure the minor axis (di) of each of the above-mentioned 300 fibers. Let ri be the number of fibers with a minor axis of di, and calculate the weight-average diameter (dw) based on the following formula. Here, the minor axis refers to the line segment perpendicular to the longest line segment. Weight-average minor axis (dw) = (Σri × di 2 ) / (Σri × di)

[0125] The aspect ratio was determined by calculating (Dw) / (dw) using the obtained weight-average fiber diameter (Dw) and weight-average minor axis (dw).

[0126] 3. Preparation of polyamide resin composition The above materials were mixed in a tumbler blender at the composition ratios (in parts by mass) shown in Table 1, and melt-kneaded at a cylinder temperature of 300 - 335 °C using a 30 mmφ vented twin-screw extruder. Then, the kneaded product was extruded into strands and cooled in a water tank. Subsequently, the strands were taken up by a pelletizer and cut to obtain pelletized polyamide resin compositions 1 - 7.

[0127] 4. Evaluation <Flexural strength and toughness> Test pieces with a length of 64 mm, a width of 6 mm, and a thickness of 0.8 mm were prepared by injection molding. The injection molding machine used, and the molding machine cylinder temperature and mold temperature are shown below. Injection molding machine: SE50DU manufactured by Sumitomo Heavy Industries, Ltd. Molding machine cylinder temperature: Polyamide resin PA-1 330 °C Polyamide resin PA-2 335 °C Mold temperature: Polyamide resin PA-1 120 °C Polyamide resin PA-2 160 °C The prepared test pieces were left standing for 24 hours at a temperature of 23°C under a nitrogen atmosphere. Subsequently, a bending test was conducted using a bending testing machine (AB5 manufactured by NTESCO) in an atmosphere of 23°C and 50% relative humidity. The test conditions were a span of 26 mm and a bending speed of 5 mm / min. From the bending test, the bending strength and the energy (toughness) required to break the test piece were measured.

[0128] <Flow length> Each polyamide resin composition was injection molded under the following conditions using a bar flow mold with a width of 10 mm and a thickness of 0.5 mm, and the flow length (mm) of the resin in the mold was measured. Injection molding machine: Tsurumi TR40S3A (manufactured by Sodick Plastic Co., Ltd.) Injection setting pressure: 2000 kg / cm 2 Cylinder setting temperature: Melting point of polyamide resin + 10°C

[0129] <Flame retardancy> Each polyamide resin composition was injection molded under the following conditions to prepare test pieces of 1 / 32 inch × 1 / 2 × 5 inches. Using the prepared test pieces, a vertical combustion test was conducted in accordance with the UL94 standard (UL Test No. UL94 dated June 18, 1991), and the flame retardancy was evaluated. Molding machine: SE50DU molding machine manufactured by Sumitomo Heavy Industries, Ltd. Cylinder temperature: Polyamide resin PA-1 330°C Polyamide resin PA-2 335°C Mold temperature: Polyamide resin PA-1 120°C Polyamide resin PA-2 160°C

[0130] <Reflow heat resistance temperature> Each polyamide resin composition was injection molded under the following conditions to prepare test pieces with a length of 64 mm, a width of 6 mm, and a thickness of 0.8 mm. Molding machine: SE50DU molding machine manufactured by Sumitomo Heavy Industries, Ltd. Cylinder temperature: Polyamide resin PA-1 330°C Polyamide resin PA-2 335°C Mold temperature: Polyamide resin PA-1 120 °C Polyamide resin PA-2 160 °C

[0131] The prepared test pieces were conditioned at a temperature of 40 °C and a relative humidity of 95% for 96 hours. The conditioned test pieces were placed on a glass epoxy substrate with a thickness of 1 mm. A temperature sensor was installed on this substrate. The glass epoxy substrate on which the test pieces were placed was set in an air reflow soldering apparatus (AIS-20-82-C, manufactured by Atech Technotron Co., Ltd.), and the reflow process with the temperature profile shown in Figure 1 was performed. As shown in Figure 1, the temperature was raised to 230 °C at a predetermined speed; then, after heating to a predetermined set temperature (a is 270 °C, b is 265 °C, c is 260 °C, d is 255 °C, e is 235 °C in Figure 1) in 20 seconds; then, the temperature was lowered to 230 °C. At this time, the maximum value of the set temperature at which the test pieces did not melt and no blisters occurred on the surface was determined, and this maximum value of the set temperature was taken as the reflow heat resistance temperature.

[0132] Next, the change amount (°C) of the reflow heat resistance temperature when using polyamide resin compositions 1, 4, and 5 with respect to the reflow heat resistance temperature when using polyamide resin composition 3, and the change amount (°C) of the reflow heat resistance temperature when using polyamide resin composition 2 with respect to the reflow heat resistance temperature when using polyamide resin composition 6 were determined.

[0133] Table 1 shows the compositions and evaluation results of each polyamide resin composition. The numerical values in the compositions in Table 1 represent parts by mass.

[0134]

Table 1

[0135] From the results of polyamide resin compositions 1 and 2, it was found that by using a fibrous reinforcing material (C) with a weight average fiber diameter of 11 μm or less, which was treated with an epoxy-based sizing agent in a state containing a flame retardant (B), the reflow heat resistance can be sufficiently increased while enhancing the flame retardancy.

Industrial Applicability

[0136] The polyamide resin composition of the present invention can sufficiently enhance the reflow heat resistance of the molded body while enhancing the flame retardancy of the molded body. Therefore, the present invention is useful, for example, in the field of electronic components.

Claims

1. A semi-aromatic polyamide resin (A) having a melting point of 280 °C or higher as measured by a differential scanning calorimeter (DSC), a flame retardant (B) which is a halogen-containing compound, and a fibrous reinforcing material (C) surface-treated with an epoxy-based sizing agent, and the weight average fiber diameter (Dw) of the fibrous reinforcing material (C) is 11.0 μm or less, a polyamide resin composition.

2. The semi-aromatic polyamide resin (A) contains a component unit (Aa) derived from a dicarboxylic acid and a component unit (Ab) derived from a diamine, the component unit (Aa) derived from the dicarboxylic acid contains a component unit derived from terephthalic acid in an amount of 75 mol% or less based on the total number of moles of the component unit (Aa) derived from the dicarboxylic acid, The polyamide resin composition according to Claim 1.

3. The semi-aromatic polyamide resin (A) has an end amino group amount of 30 mmol / kg or more and 200 mmol / kg or less, The polyamide resin composition according to Claim 1.

4. The fibrous reinforcing material (C) has an aspect ratio of less than 1.5 in cross section, The polyamide resin composition according to Claim 1.

5. The semi-aromatic polyamide resin (A) contains a component unit (Aa) derived from a dicarboxylic acid and a component unit (Ab) derived from a diamine, the component unit (Aa) derived from the dicarboxylic acid contains a component unit derived from terephthalic acid, the component unit (Ab) derived from the diamine contains a component unit derived from 1,6-diaminohexane, The polyamide resin composition according to Claim 1.

6. The content of the component unit derived from 1,6-diaminohexane is 70 mol% or more and 100 mol% or less based on the total number of moles of the component unit (Ab) derived from the diamine, The polyamide resin composition according to Claim 5.

7. A molded article obtained by molding the polyamide resin composition according to any one of Claims 1 to 6, a molded article.

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