Polyamide resin composition, and molding

Abstract

To provide a polyamide resin composition capable of heightening reflow heat resistance of a molding while heightening flame resistance and tracking resistance, and a molding of the same.SOLUTION: A polyamide resin composition includes: a polyamide resin (A) having a melting point measured by a differential scanning calorimeter (DSC) of 280°C or higher; a phosphinic acid-based compound (B); a polyolefin resin (C) modified by an unsaturated carboxylic acid or a derivative thereof; and a bromine-based flame-retarder, wherein a ratio of a mass of the bromine-based flame-retarder (D) to a total mass of the polyolefin-based resin (C) is 120 mass% or more and 2,000 mass% or less, and a ratio of a mass of the bromine-based flame-retarder (D) to a total mass of the phosphinic acid-based compound (B) is 800 mass% or more and 4,000 mass% or less.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Polyamide resin compositions have been known as molding materials. Polyamide resin compositions are widely used as materials for various parts, such as automotive parts and electrical and electronic parts, and are known to have excellent mechanical strength in molded articles. When polyamide resin compositions are used for automotive parts (such as bus bars) and electrical and electronic parts, it is desirable that the polyamide resin compositions be imparted with flame retardancy.

[0003] As a flame-retardant polyamide resin composition, for example, Patent Document 1 discloses a polyamide resin composition containing a polyamide resin, a rubbery polymer having a reactive functional group, a phosphorus-based flame retardant, and an inorganic filler, each in a specific weight amount. Patent Document 1 states that the polyamide resin composition is excellent in flame retardancy, high rigidity, high toughness, and good appearance.

[0004] However, when polyamide resin compositions are used for automobile parts (such as bus bars) and electric / electronic parts, tracking fracture may occur. Therefore, when polyamide resin compositions are used for these applications, it is required to improve the tracking resistance of the molded articles.

[0005] As a polyamide resin composition with improved tracking resistance, for example, Patent Document 2 discloses a flame-retardant resin composition comprising a polyamide resin, a halogen-based flame retardant, an organic phosphinic acid or its salt, and a flame-retardant assistant. According to Patent Document 2, the flame-retardant resin composition has improved flame retardancy and tracking resistance. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2019-065285 [Patent Document 2] International Publication No. 2006 / 090751 Summary of the Invention [Problem to be solved by the invention]

[0007] As described in Patent Document 2, a polyamide resin composition having improved flame retardancy and tracking resistance is known.

[0008] When a molded article of a polyamide resin composition containing a semi-aromatic polyamide resin is used for automobile parts, electrical and electronic parts, etc., the molded article may be reflow soldered to a substrate. During this process, the moisture contained in the molded article evaporates due to heating in the reflow process, and the resulting vapor pressure can cause blisters (expansion) in the molded article. 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 cause blisters due to heating (high reflow heat resistance).

[0009] According to the investigations of the present inventors, when the polyamide resin compositions described in Patent Documents 1 and 2 were used, it was not possible to improve the reflow heat resistance of the molded article.

[0010] An object of the present invention is to provide a polyamide resin composition and a molded article thereof which can improve the flame retardancy and tracking resistance of the molded article while also improving reflow heat resistance. [Means for solving the problem]

[0011] In order to solve the above problems, one aspect of the present invention relates to the following polyamide resin compositions [1] to [7]. [1] A polyamide resin composition comprising: a polyamide resin (A) having a melting point of 280°C or higher as measured by differential scanning calorimetry (DSC); a phosphinic acid compound (B); a polyolefin resin (C) modified with an unsaturated carboxylic acid or a derivative thereof; and a brominated flame retardant (D), wherein the mass ratio of the brominated flame retardant (D) to the total mass of the polyolefin resin (C) is 120% by mass or more and 2000% by mass or less, and the mass ratio of the brominated flame retardant (D) to the total mass of the phosphinic acid compound (B) is 800% by mass or more and 4000% by mass or less. [2] The content of the phosphinic acid compound (B) is 0.50 mass% or more and 1.50 mass% or less based on the total mass of the polyamide resin composition. [1] The polyamide resin composition according to [1]. [3] The content of the polyolefin resin (C) is 1.00 mass% or more and 10.00 mass% or less, based on the total mass of the polyamide resin composition. [1] or [2]. The polyamide resin composition. [4] The content of the brominated flame retardant (D) is 12.00 mass% or more and 20.00 mass% or less, based on the total mass of the polyamide resin composition. The polyamide resin composition according to any one of [1] to [3]. [5] The polyamide resin (A) contains a component unit (Aa) derived from a dicarboxylic acid and a component unit (Ab) derived from a diamine, The dicarboxylic acid-derived unit (Aa) includes a terephthalic acid-derived unit, The diamine-derived component unit (Ab) includes a 1,6-diaminohexane-derived component unit. The polyamide resin composition according to any one of [1] to [4]. [6] The heat of fusion (ΔH) of the polyamide resin (A) is 30 J / g or more. The polyamide resin composition according to any one of [1] to [5]. [7] The content of phosphorus contained in the phosphinic acid compound (B) is 20% by mass or more and 30% by mass or less, based on the total mass of the phosphinic acid compound (B). The polyamide resin composition according to any one of [1] to [6].

[0012] Another aspect of the present invention for solving the above problems relates to the following molded article [8]. [8] A molded article obtained by molding the polyamide resin composition according to any one of [1] to [7]. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a polyamide resin composition and a molded article thereof, which can improve the flame retardancy and tracking resistance of the molded article while also improving the reflow heat resistance. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram showing the relationship between the temperature and time of the reflow process in the reflow heat resistance test carried out in the examples of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments.

[0016] 1. Polyamide resin composition The polyamide resin composition according to the present embodiment comprises a polyamide resin (A) having a melting point of 280°C or higher as measured by differential scanning calorimetry (DSC), a phosphinic acid compound (B), a polyolefin resin (C) modified with an unsaturated carboxylic acid or a derivative thereof, and a brominated flame retardant (D). The mass ratio of the brominated flame retardant (D) to the total mass of the polyolefin resin (C) is 120% by mass or more and 2000% by mass or less, and the mass ratio of the brominated flame retardant (D) to the total mass of the phosphinic acid compound (B) is 800% by mass or more and 4000% by mass or less.

[0017] The polyamide resin composition has flame retardancy because it contains the brominated flame retardant (D). However, a polyamide resin composition containing the brominated flame retardant (D) is likely to reduce the tracking resistance of a molded article.

[0018] When a molded article of a polyamide resin composition is used as an insulating material for insulating conductive members in electrical and electronic components, a voltage is applied to the molded article of the polyamide resin composition. Since the brominated flame retardant (D) in the polyamide resin composition has a lower dielectric constant than the polyamide resin (A), the voltage is easily applied to the brominated flame retardant (D). Heat is thus generated at the interface between the matrix resin and the brominated flame retardant (D) in the polyamide resin composition, and thermal energy is supplied to the molded article from the interface, resulting in the precipitation of char. Repeated application of voltage is then thought to cause the charred portion to grow from the precipitated char, and the charred portion precipitated on the surface of the molded article bridges the electrodes, resulting in tracking failure.

[0019] In response to this, the present inventors attempted to enhance both flame retardancy and tracking resistance by incorporating a phosphinic acid compound (B), such as phosphinic acid or a phosphinic acid salt compound, into a polyamide resin composition containing a brominated flame retardant (D). When heat is applied, the phosphinic acid compound (B) thermally decomposes to produce phosphoric acid. The generated phosphoric acid is believed to rapidly hydrolyze the polyamide resin (A). Because the hydrolysis of the polyamide resin (A) is an endothermic reaction, it is believed that the thermal energy supplied to the molded article from the interface between the matrix resin and the brominated flame retardant (D) is absorbed during the decomposition of the polyamide resin (A). This is believed to suppress char precipitation and enhance tracking resistance.

[0020] However, increasing the content of the phosphinic acid compound (B) to improve tracking resistance failed to sufficiently improve reflow heat resistance. The phosphinic acid compound (B) thermally decomposes to produce phosphoric acid due to shear heat generated during kneading of the polyamide resin composition and heating to melt the polyamide resin composition during molding. Therefore, hydrolysis of the polyamide resin (A) may occur during the production of the polyamide resin composition or during the production of a molded article, resulting in a decrease in the molecular weight of the polyamide resin (A). As a result, the mechanical strength of the polyamide resin composition constituting the molded article is reduced, and the molded article may be unable to withstand the vapor pressure generated by the evaporation of water contained in the molded article during the reflow process performed to mount electrical and electronic components, making it more susceptible to blistering. For these reasons, there is a trade-off between improved tracking resistance and improved reflow heat resistance.

[0021] In response to this, the present inventors have found that by adding a polyolefin resin (C) modified with an unsaturated carboxylic acid or its derivative (hereinafter referred to as "modified polyolefin resin (C)") to a polyamide resin composition containing a brominated flame retardant (D), it is possible to improve tracking resistance and reflow heat resistance without increasing the content of phosphinic acid or phosphinic acid salt compound.

[0022] The compatibility of the brominated flame retardant (D) with the modified polyolefin resin (C) is lower than its compatibility with the polyamide resin (A). Therefore, the addition of the modified polyolefin resin (C) increases the amount of components in the matrix of the polyamide resin composition that are less compatible with the brominated flame retardant (D). This increases the particle size of the brominated flame retardant (D) and the area of ​​the interface between the matrix resin and the brominated flame retardant (D). This reduces the specific surface area of ​​the brominated flame retardant (D), thereby reducing the amount of heat energy per unit area supplied to the molded article from the interface when a voltage is applied. As a result, tracking fracture is less likely to occur.

[0023] Based on these findings, the present inventors conducted research and found that the tracking resistance of a polyamide resin composition can be improved by first setting the content of the brominated flame retardant (D) relative to the content of the modified polyolefin resin (C) ((D) / (C)) to 2000 mass% or less, and setting the content of the brominated flame retardant (D) relative to the total mass of the phosphinic acid compound (B) ((D) / (B)) to 4000 mass% or less. By setting the content ((D) / (C)) to 2000 mass% or less, the amount of modified polyolefin resin (C) relative to the brominated flame retardant (D) increases, thereby reducing the specific surface area of ​​the brominated flame retardant (D), and thereby reducing the thermal energy per unit area supplied to the molded article when a voltage is applied. Furthermore, by making the content ((D) / (B)) 4000 mass% or less, the amount of the phosphinic acid compound (B) relative to the brominated flame retardant (D) is large, and therefore the molded article is more likely to absorb the heat generated when a voltage is applied to it.

[0024] Furthermore, by setting the content of the brominated flame retardant (D) relative to the content of the modified polyolefin resin (C) ((D) / (C)) to 120% by mass or more and setting the content of the brominated flame retardant (D) relative to the total mass of the phosphinic acid compound (B) ((D) / (B)) to 800% by mass or more, the reflow heat resistance of the molded article can be improved. By setting the content ((D) / (C)) to 120% by mass or more, the amount of modified polyolefin resin (C) relative to the brominated flame retardant (D) can be reduced, thereby preventing the brominated flame retardant (D) from coarsening in the polyamide resin composition. This allows the area of ​​the interface between the brominated flame retardant (D) and the matrix resin to be appropriately reduced. Since blisters are also likely to occur at this interface, reducing the area of ​​this interface can make blisters less likely to occur. Furthermore, by making the content ((D) / (B)) 800% by mass or more, the content of the phosphinic acid compound (B) relative to the bromine-based flame retardant (D) is not made too large, and the occurrence of blisters can be suppressed.

[0025] For these reasons, the polyamide resin composition according to this embodiment can improve the flame retardancy, tracking resistance, and reflow heat resistance of the molded article.

[0026] 1-1. Polyamide resin (A) The polyamide resin (A) is a polyamide resin having a melting point of 280°C or higher as measured by a differential scanning calorimeter (DSC). The polyamide resin (A) forms crystals in the molded product, which can increase the mechanical strength (such as tensile strength) of the molded product. Furthermore, since the polyamide resin (A) has a high melting point, it can be prevented from melting during the reflow process. The method for measuring the melting point of the polyamide resin (A) will be described later.

[0027] The 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 polyamide resin containing the component unit (Aa) derived from a dicarboxylic acid and the component unit (Ab) derived from a diamine will be described.

[0028] (Component unit (Aa) derived from dicarboxylic acid) The dicarboxylic acid-derived component units (Aa) preferably include component units derived from aromatic dicarboxylic acids, and more preferably include component units derived from terephthalic acid.

[0029] The content of the component units derived from terephthalic acid is preferably 40 mol% to 100 mol%, more preferably 60 mol% to 99 mol%, even more preferably 60 mol% to 85 mol%, and particularly preferably 60 mol% to 65 mol%, based on the total number of moles of the component units (Aa) derived from dicarboxylic acids. When the content of the component units derived from terephthalic acid is 40 mol% or more, the crystallinity of the polyamide resin (A) is further increased, thereby improving the chemical resistance of the molded article. Furthermore, since terephthalic acid contains an aromatic ring in the molecule, the inclusion of a certain amount of component units derived from terephthalic acid tends to rigidify the molecular chain of the polyamide resin (A). Therefore, the amide groups of the polyamide resin (A) are less likely to come into contact with water molecules, making it difficult for hydrogen bonds to form between them. This further suppresses hydrolysis of the polyamide resin (A) by phosphoric acid generated from the phosphinic acid compound (B). As a result, the reflow heat resistance of the molded article is further improved. For the same reason, if the content of component units derived from terephthalic acid is 60 mol % or more, the reflow heat resistance of the molded article is more sufficiently improved.

[0030] The dicarboxylic acid-derived component unit (Aa) may contain other dicarboxylic acid-derived component units. Examples of other dicarboxylic acids include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids other than terephthalic acid. Of these, aliphatic dicarboxylic acids are preferred.

[0031] 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.

[0032] The content of the component units derived from the above aliphatic dicarboxylic acid is preferably 0 mol % or more and 60 mol % or less, and more preferably 0 mol % or more and 40 mol % or less, relative to the total number of moles of the component units (Aa) derived from the dicarboxylic acid.

[0033] Examples of the alicyclic dicarboxylic acid include cyclohexanedicarboxylic acid and its esters.

[0034] Examples of aromatic dicarboxylic acids other than terephthalic acid include isophthalic acid, 2-methylterephthalic acid, and naphthalenedicarboxylic acid.

[0035] The content of component units derived from alicyclic dicarboxylic acids and aromatic dicarboxylic acids 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, based on the total number of moles of component units (Aa) derived from dicarboxylic acids.

[0036] The dicarboxylic acid-derived component units (Aa) preferably contain 60 mol% to 99 mol% of component units derived from terephthalic acid and 1 mol% to 40 mol% of component units derived from an aliphatic dicarboxylic acid having 4 to 20 carbon atoms, relative to the total number of moles of component units derived from dicarboxylic acid-derived component units (Aa), and more preferably contain 60 mol% to 85 mol% of component units derived from terephthalic acid and 15 mol% to 40 mol% of component units derived from an aliphatic dicarboxylic acid having 4 to 20 carbon atoms. By containing 60 mol% or more of component units derived from terephthalic acid, the reflow heat resistance of the molded article can be more sufficiently improved. By containing 1 mol% or more of the component units derived from the aliphatic dicarboxylic acid, the aromatic ring concentration in the polyamide resin (A) is not too high, and a decrease in tracking resistance is likely to be suppressed.

[0037] (Diamine-derived component unit (Ab)) The diamine-derived component unit (Ab) includes, for example, a component unit derived from an aliphatic diamine having from 4 to 15 carbon atoms, a component unit derived from an alicyclic diamine having from 4 to 20 carbon atoms, and a component unit derived from an aromatic diamine.

[0038] The number of carbon atoms in the aliphatic diamine is preferably 4 or more and 12 or less, and more preferably 6 or more and 12 or less. Examples of the aliphatic diamine include linear alkylenediamines and branched alkylenediamines.

[0039] Examples of the linear alkylenediamine include 1,4-diaminobutane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, and 1,12-diaminododecane. Among these, 1,6-diaminohexane, 1,9-nonanediamine, and 1,10-diaminodecane are preferred, and 1,6-diaminohexane is more preferred. The linear alkylenediamine may be contained alone or in combination of two or more.

[0040] Examples of the branched alkylenediamine 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, Examples of suitable diaminooctane include 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 and 2-methyl-1,8-diaminooctane are preferred, with 2-methyl-1,5-diaminopentane being more preferred.

[0041] The content of the component units derived from the aliphatic diamine is preferably 30 mol % or more and 100 mol % or less, and more preferably 70 mol % or more and 100 mol % or less, based on the total number of moles of the component units (Ab) derived from the diamine.

[0042] 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.

[0043] The content of the component units derived from the above alicyclic diamine and aromatic diamine is preferably 0 mol % or more and 70 mol % or less, and more preferably 0 mol % or more and 30 mol % or less, relative to the total number of moles of the component units (Ab) derived from diamine.

[0044] The constituent units of the polyamide resin (A) and their ratios can be calculated from the charge ratios when the polyamide resin (A) is prepared, or can be measured by the NMR method.

[0045] 1 In the case of H-NMR measurement, for example, a nuclear magnetic resonance apparatus (ECX400 model 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 observation nucleus is 1 The conditions are H (400 MHz), sequence is single pulse, pulse width is 5.12 μsec (45° pulse), repetition time is 7.0 sec, and the number of accumulations is 500 or more. The reference chemical shift is set to 0 ppm for hydrogen in tetramethylsilane, but similar results can also be obtained by setting the peak derived from residual hydrogen in deuterated orthodichlorobenzene at 7.10 ppm as the reference value for the chemical shift. 1 Peaks such as H can be assigned by conventional methods.

[0046] 13 In the case of C-NMR measurement, for example, a nuclear magnetic resonance spectrometer (ECP500 model manufactured by JEOL Ltd.) is used as the measurement device, a mixed solvent of ortho-dichlorobenzene / heavy benzene (80 / 20% by volume) is used as the solvent, the measurement temperature is 120°C, and the observation nucleus is 13 The conditions were: C (125 MHz), single pulse proton decoupling, 45° pulse, repetition time 5.5 seconds, accumulation number 10,000 or more, and chemical shift reference value 27.50 ppm. Assignment of various signals was performed based on the standard method, and quantification could be performed based on the accumulated value of signal intensity.

[0047] In the polyamide resin (A), the dicarboxylic acid-derived component (Aa) preferably contains component units derived from terephthalic acid, and the diamine-derived component units (Ab) preferably contain component units derived from 1,6-diaminohexane.

[0048] Specific examples of the polyamide resin (A) include polyamide 6T6I, polyamide 6T66, and polyamide 6TDT. Of these, polyamide 6T66 is preferred. That is, the semi-aromatic polyamide resin (A) preferably contains, as the dicarboxylic acid-derived component units (Aa), component units derived from terephthalic acid and component units derived from adipic acid, and, as the diamine-derived component units (Ab), component units derived from 1,6-diaminohexane.

[0049] The polyamide resin (A) may contain only one type of polyamide resin or two or more types of polyamide resins, but preferably contains only one type of polyamide resin. Using only one type of polyamide resin can enhance the crystallinity of the polyamide resin (A) compared to using two or more types of polyamide resins. This is thought to be because the resin molecules can be aligned to more easily form crystalline portions without causing mutual miscibility between the multiple types of polyamide resins. Furthermore, by increasing the crystallinity of the polyamide resin (A), molecular chain motion at high temperatures can be suppressed, thereby suppressing deformation of the molded product during reflow treatment. This suppresses the generation of blisters due to evaporation of moisture inside the molded product, thereby further improving reflow heat resistance. In this specification, polyamide resins (A) containing the same type of component units but with different amounts of the component units are considered to be two or more types of polyamide resins.

[0050] The dicarboxylic acid-derived component units of the polyamide resin (A) may include component units derived from biomass-derived dicarboxylic acids, and the diamine-derived component units may include component units derived from biomass-derived diamines. The polyamide resin (A) may also be a biomass-derived polyamide resin (A) obtained by polymerizing raw materials including biomass-derived raw materials.

[0051] In this embodiment, the ratio of the total number of carbon atoms constituting the aromatic rings to the total number of carbon atoms constituting the constituent units contained in the polyamide resin (A) is preferably 20% to 32%, more preferably 25% to 30%. A ratio of 20% or more can further increase the mechanical strength (such as tensile strength) of the molded article. Furthermore, a ratio of 32% or less can reduce the proportion of aromatic rings in the molecular chains of the polyamide resin (A) when a voltage is applied to the surface of a resin member, making carbonization of the surface of the resin member less likely to occur. This can further improve the tracking resistance of the molded article. The carbon atom ratio can be adjusted by the combination of dicarboxylic acid and diamine used to prepare the polyamide resin (A) and the content ratio of the aromatic dicarboxylic acid and aromatic diamine. The carbon atom ratio can be calculated from the charge ratio or measured by NMR. The NMR method can be the same as described above.

[0052] (Physical Properties) From the viewpoint of further increasing the mechanical strength of the molded article, the melting point of the polyamide resin (A) is 280° C. or higher, preferably 290° C. or higher, and more preferably 300° C. or higher. Furthermore, from the viewpoint of suppressing decomposition of the amide bond of the polyamide resin (A), the melting point of the polyamide resin (A) is preferably 330° C. or lower.

[0053] The melting point of the polyamide resin (A) can be adjusted to the above range by adjusting the composition of the polyamide resin (A). For example, the melting point can be increased by increasing the content of component units derived from terephthalic acid, which will be described later.

[0054] The polyamide resin (A) preferably has a glass transition temperature (Tg) measured by differential scanning calorimetry (DSC) of 70°C to 145°C, more preferably 75°C to 125°C, and even more preferably 80°C to 100°C. A glass transition temperature (Tg) of 70°C or higher increases the temperature at which molecular mobility becomes active in high-temperature environments, thereby suppressing molecular mobility and further improving the heat resistance of the polyamide resin composition and molded articles. A glass transition temperature (Tg) of 145°C or lower makes it easier to maintain the fluidity of the resin composition without excessively increasing the mold temperature during molding, thereby improving molding processability.

[0055] The heat of fusion (ΔH) of the polyamide resin (A) measured by differential scanning calorimetry (DSC) is preferably greater than 5 J / g. The heat of fusion is an index of the crystallinity of a resin, with a larger heat of fusion indicating higher crystallinity. When the heat of fusion (ΔH) of the polyamide resin (A) exceeds 5 J / g, the crystallinity is increased, thereby enabling the mechanical strength (such as bending strength) of the resulting molded article to be increased. Furthermore, from the viewpoint of further increasing the crystallinity of the polyamide resin (A), further increasing the mechanical strength of the molded article, and reducing the likelihood of blistering, the heat of fusion (ΔH) is preferably 30 J / g or more, more preferably 40 J / g or more. The upper limit of the heat of fusion (ΔH) is not particularly limited, but is, for example, 100 J / g.

[0056] The melting point and heat of fusion (ΔH) of the polyamide resin (A) can be measured using a differential scanning calorimeter (DSC220C model, manufactured by Seiko Instruments Inc.).

[0057] Specifically, approximately 5 mg of polyamide resin (A) is sealed in a measuring aluminum pan and heated from room temperature to 350°C at 10°C / min. 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, it is heated a second time to 350°C at 10°C / min. The temperature (°C) of the endothermic peak during this second heating is taken as the melting point (Tm) of polyamide resin (A), and the inflection point corresponding to the glass transition is taken as the glass transition temperature (Tg). The heat of fusion (ΔH) is determined from the area of ​​the endothermic peak during melting during the first heating process in accordance with JIS K7122.

[0058] The intrinsic viscosity [η] of the polyamide resin (A), measured in 96.5% sulfuric acid at 25°C, is preferably 0.7 dL / g or more and 1.2 dL / g or less, more preferably 0.7 dL / g or more and 1.0 dL / g or less, and even more preferably 0.7 dL / g or more and 0.9 dL / g or less. When the intrinsic viscosity [η] of the polyamide resin (A) is 0.7 dL / g or more, the molecular weight of the polyamide resin (A) can be sufficiently increased, and the decrease in molecular weight of the polyamide resin (A) due to the phosphinic acid compound (B) can be more sufficiently suppressed. This can further improve the reflow heat resistance of the molded article. When the intrinsic viscosity [η] is 1.2 dL / g or less, the decrease in fluidity of the polyamide resin composition during molding can be more sufficiently suppressed. Furthermore, when the intrinsic viscosity [η] is 0.9 dL / g or less, the decrease in fluidity of the polyamide resin composition during molding can be more sufficiently suppressed. The intrinsic viscosity [η] can be adjusted by adjusting the molar ratio of the dicarboxylic acid-derived component unit (Aa) and the diamine-derived component unit (Ab). Specifically, the closer the molar ratio of the carboxylic acid-derived component unit (Aa) and the diamine-derived component unit (Ab) is to 1:1, the higher the intrinsic viscosity can be. It can also be adjusted by the amount of end-capping of the polyamide resin (A).

[0059] The intrinsic viscosity [η] of polyamide resin (A) can be measured as follows. 0.5 g of polyamide resin (A) is dissolved in 50 ml of 96.5% sulfuric acid solution to prepare a sample solution. The flow time of the obtained solution at 25°C ± 0.05°C is measured using an Ubbelohde viscometer, and the intrinsic viscosity [η] is calculated 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: Number of seconds for sample solution to flow down (seconds) t0: Number of seconds the blank sulfuric acid flows (seconds) ηSP=(t-t0) / t0

[0060] The polyamide resin (A) can be produced by the same method as that for known polyamide resins, for example, by polycondensing a dicarboxylic acid and a diamine in a homogeneous solution. Specifically, the polyamide resin (A) can be produced by heating a dicarboxylic acid and a diamine in the presence of a catalyst to obtain a low-order condensate, as described in WO 03 / 085029, and then applying shear stress to a melt of the low-order condensate to polycondense it.

[0061] The content of polyamide resin (A) is preferably 25% by mass or more and 55% by mass or less, preferably 30% by mass or more and 45% by mass or less, and more preferably 33% by mass or more and 43% by mass or less, based on the total mass of the polyamide resin composition. When the content is 33% by mass or more, the mechanical strength (such as tensile strength) of the polyamide resin composition can be further increased. When the content is 43% by mass or less, other components such as the phosphinic acid compound (B), modified polyolefin resin (C), and brominated flame retardant (D), which will be described later, can be sufficiently contained in the polyamide resin composition.

[0062] 1-2. Phosphinic acid compounds (B) In this embodiment, the polyamide resin composition contains a phosphinic acid compound (B). In this specification, phosphinic acid and its salts (i.e., phosphinic acid salt compounds) correspond to the "phosphinic acid compound." The phosphinic acid compound (B) preferably contains at least one of phosphinic acid and phosphinic acid salt compounds. Of the phosphinic acid and phosphinic acid salt compounds, phosphinic acid salt compounds are preferred from the viewpoint of suppressing evaporation during kneading of the polyamide resin composition.

[0063] The phosphinate compound is, for example, a compound represented by the following formula (I) or formula (II).

[0064] [ka]

[0065] In formula (I) and formula (II), R 1 and R 2 R are each independently a linear or branched alkyl or aryl group having 1 to 6 carbon atoms. 3 is a linear or branched alkylene group having from 1 to 10 carbon atoms, an arylene group having from 6 to 10 carbon atoms, an alkylarylene group having from 6 to 10 carbon atoms, or an arylalkylene group having from 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 of 1 to 4.

[0066] 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, and calcium methanedi(methylphosphinate). Methane di(methylphosphinate), magnesium methane di(methylphosphinate), aluminum methane di(methylphosphinate), zinc methane di(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, etc. Among these, calcium dimethylphosphinate, aluminum dimethylphosphinate, zinc dimethylphosphinate, calcium ethylmethylphosphinate, aluminum ethylmethylphosphinate, zinc ethylmethylphosphinate, calcium diethylphosphinate, aluminum diethylphosphinate, and zinc diethylphosphinate are preferred, with aluminum diethylphosphinate being more preferred.

[0067] The phosphorus content of the phosphinic acid compound (B) is preferably 20% by mass or more and 30% by mass or less, and more preferably 20% by mass or more and 25% by mass or less, based on the total mass of the phosphinic acid compound (B). When the phosphorus content is 20% by mass or more, phosphoric acid is more likely to be generated from the phosphinic acid compound (B) by heat generated by applying a voltage to the molded article, thereby making hydrolysis of the polyamide resin (A) more likely to occur. This makes it easier for heat generated at the interface between the brominated flame retardant (D) and the matrix resin to be absorbed, thereby further improving the tracking resistance of the molded article. Furthermore, when the content is 30% by mass or less, excessive generation of phosphoric acid during melt-kneading of the polyamide resin composition is suppressed, thereby further suppressing decomposition of the polyamide resin (A). This further improves the reflow heat resistance of the molded article. The phosphorus content can be measured, for example, by inductively coupled plasma (ICP) emission spectrometry.

[0068] The content of the phosphinic acid compound (B) is preferably 0.50% by mass or more and 1.50% by mass or less, and more preferably 0.75% by mass or more and 1.25% by mass or less, based on the total mass of the polyamide resin composition. When the content is 1% by mass or more, the tracking resistance of the molded article can be further improved. When the content is 1.5% by mass or less, decomposition of the polyamide resin (A) by phosphoric acid generated from the phosphinic acid compound (B) can be further suppressed, thereby further improving reflow heat resistance.

[0069] 1-3. Modified polyolefin resin (C) In this embodiment, the polyamide resin composition contains a polyolefin resin (C) modified with an unsaturated carboxylic acid or a derivative thereof.

[0070] The modified polyolefin resin (C) can be obtained by subjecting a polyolefin resin before modification to a modification reaction using a compound containing a carboxylic acid group (including a carboxylic acid anhydride group).

[0071] Examples of polyolefin resins before modification include ethylene polymers, propylene polymers, butene polymers, and copolymers of these olefins (e.g., ethylene-α-olefin copolymers), etc. Among these, ethylene polymers are preferred.

[0072] Examples of the α-olefin other than ethylene in the ethylene-α-olefin copolymer include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, etc. Among these, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene are preferred.

[0073] Examples of compounds containing a carboxylic acid group include α,β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, and phthalic acid. Examples of compounds containing a carboxylic acid anhydride group include dicarboxylic acid anhydrides having an α,β-unsaturated bond such as maleic anhydride, itaconic anhydride, and phthalic anhydride. Of these, maleic anhydride is preferred. This increases the affinity between the polyamide resin (A) and the modified polyolefin resin (C), making the modified polyolefin resin (C) more easily dispersible in the polyamide resin composition.

[0074] The content of carboxylic acid groups in the modified polyolefin resin (C) (modification amount) is preferably 0.1% by mass or more and 5.0% by mass or less, more preferably 0.2% by mass or more and 3.0% by mass or less, and even more preferably 0.5% by mass or more and 1.5% by mass or less. When the content of carboxylic acid groups is within the above range, the impact resistance and elongation of the resin composition tend to be improved.

[0075] The content of carboxylic acid groups in the modified polyolefin resin (C) (modification amount) can be calculated from the charge ratio when preparing the modified polyolefin resin, or can be measured by the NMR method. For the NMR method, the same method as described for the semi-aromatic polyamide resin (A) can be used.

[0076] A method in which a polyolefin resin before modification is subjected to a modification reaction using a compound containing a carboxylic acid group (including a carboxylic anhydride group) is, for example, a graft modification method.

[0077] Graft modification can be carried out by various conventionally known methods. For example, it may be carried out by a melt modification method in which the polyolefin resin before modification is melted using an extruder and a graft monomer is added to carry out graft copolymerization, or it may be carried out by a solution modification method in which the polyolefin resin before modification is dissolved in a solvent and a graft monomer is added to carry out graft copolymerization. In either case, it is preferable to carry out the reaction in the presence of a radical initiator in order to efficiently graft copolymerize the graft monomer.

[0078] The content of the modified polyolefin resin (C) is preferably 1.00% by mass or more and 10.00% by mass or less, and more preferably 1.50% by mass or more and 5.00% by mass or less, based on the total mass of the polyamide resin composition. A content of 1.00% by mass or more reduces the specific surface area of ​​the brominated flame retardant (D), thereby further reducing the thermal energy supplied to the molded article. This further improves the tracking resistance of the molded article. A content of 10.00% by mass or less suppresses coarsening of the brominated flame retardant (D), thereby making it less likely for blisters to form at the interface between the brominated flame retardant (D) and the matrix resin. As a result, the reflow heat resistance of the molded article is further improved.

[0079] 1-4. Brominated flame retardants (D) In the present embodiment, the polyamide resin composition contains a brominated flame retardant (D). In this specification, the term "brominated flame retardant" refers to a bromine-containing compound that can impart flame retardancy to the polyamide resin composition.

[0080] Examples of the brominated flame retardant (D) include brominated polystyrene, polybrominated styrene, brominated polyphenylene ether, etc. Among these, the brominated flame retardant (D) is preferably brominated polystyrene or polybrominated styrene, and more preferably brominated polystyrene.

[0081] The content of the brominated flame retardant (D) is preferably 12.00% by mass or more and 20.00% by mass or less, and more preferably 14.00% by mass or more and 18.00% by mass or less, based on the total mass of the polyamide resin composition. A content of 12.00% by mass or more can further enhance the flame retardancy of the molded article. Furthermore, a content of 20.00% by mass or less can reduce the thermal energy supplied from the brominated flame retardant (D) to the molded article when a voltage is applied to the molded article, thereby further enhancing the tracking resistance of the molded article.

[0082] 1-5.Other ingredients The polyamide resin composition may contain other known components.

[0083] Examples of other components include flame retardant aids, nucleating agents, lubricants, reinforcing materials, polyolefin resins, styrene-based thermoplastic elastomers, anti-drip agents, halogen scavengers, colorants, heat stabilizers, corrosion resistance improvers, anti-drip agents, ion scavengers, elastomers (rubbers), antistatic agents, mold release agents, antioxidants (phenols, amines, sulfurs, phosphorus compounds, etc.), heat stabilizers other than those mentioned above (lactone compounds, vitamin E compounds, hydroquinones, etc.), light stabilizers (benzotriazoles, triazines, benzophenones, benzoates, hindered amines, oxanilides, etc.), and the like.

[0084] (Flame retardant synergist) Examples of the flame retardant synergist include anhydrous sodium antimonate, hydrotalcite, boehmite, zinc stannate, iron oxide, zinc oxide, tin oxide, and the like.

[0085] The content of the flame retardant aid is preferably 0.5% by mass or more and 5.0% by mass or less, and 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.

[0086] (nucleating agent) The nucleating agent can promote the crystallization of the polyamide resin (A), thereby further increasing the tensile strength and elastic modulus of the molded article.

[0087] Examples of nucleating agents include metal salt compounds such as sodium 2,2-methylenebis(4,6-di-t-butylphenyl)phosphate, aluminum tris(pt-butylbenzoate), and stearates; sorbitol compounds such as bis(p-methylbenzylidene)sorbitol and bis(4-ethylbenzylidene)sorbitol; and inorganic substances such as 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.

[0088] Talc generally contains hydrous magnesium silicate (SiO2: 58-64%, MgO: 28-32%, Al2O3: 0.5-5%, Fe2O3: 0.3-5%) as its main component. The average particle size of the talc is not particularly limited, but is preferably 1-15 μm. When the average particle size of the talc is within the above range, the talc can be easily dispersed in the polyamide resin (A) without impairing the fluidity of the polyamide resin composition. From the same viewpoint, the average particle size of the talc is more preferably 1-7.5 μm. The average particle size of the talc can be measured by a laser diffraction method, for example, using a Shimadzu particle size distribution analyzer (SALD-2000A) manufactured by Shimadzu Corporation.

[0089] The content of the nucleating agent is preferably 0.10% by mass or more and 5.00% by mass or less, and more preferably 0.10% by mass or more and 3.00% 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, the crystallinity of the resin member is easily increased sufficiently, and sufficient mechanical strength is easily obtained.

[0090] (lubricant) The lubricant improves the injection flowability of the polyamide resin composition and improves the appearance of the resulting resin part. The lubricant can be a metal salt of a fatty acid, such as a metal salt of an oxycarboxylic acid or a metal salt of a higher fatty acid.

[0091] The hydroxycarboxylic acid constituting the hydroxycarboxylic acid metal salt may be an aliphatic hydroxycarboxylic acid or an aromatic hydroxycarboxylic acid. Examples of the aliphatic hydroxycarboxylic acid include aliphatic hydroxycarboxylic 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-hydroxyhexaeicosanoic acid, α-hydroxyoctaeicosanoic 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 aromatic hydroxycarboxylic acid include salicylic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, gallic acid, mandelic acid, and trovic acid.

[0092] Examples of the metal constituting the metal oxycarboxylic acid salt include alkali metals such as lithium, and alkaline earth metals such as magnesium, calcium and barium.

[0093] Of these, the metal oxycarboxylic acid salt is preferably a metal salt of 12-hydroxystearic acid, and more preferably magnesium 12-hydroxystearate and calcium 12-hydroxystearate.

[0094] Examples of the higher fatty acids that constitute the higher fatty acid metal salts include higher fatty acids having 15 to 30 carbon atoms, such as stearic acid, oleic acid, behenic acid, behenic acid, and montanic acid.

[0095] Examples of metals constituting the above higher fatty acid metal salts include calcium, magnesium, barium, lithium, aluminum, zinc, sodium, and potassium.

[0096] Of these, the higher fatty acid metal salts are preferably calcium stearate, magnesium stearate, barium stearate, calcium behenate, sodium montanate, and calcium montanate.

[0097] The content of the lubricant is preferably 0.01% by mass or more and 1.30% by mass or less relative to 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 tends to be improved, and the appearance of the obtained molded product tends to be improved. When the content of the lubricant is 1.30% by mass or less, gas due to decomposition of the lubricant is unlikely to be generated during molding, and the appearance of the product tends to be good.

[0098] (Reinforcement material) The reinforcing material may be an inorganic filler. Examples of reinforcing materials include fibrous reinforcing materials such as glass fiber, wollastonite, potassium titanate whiskers, calcium carbonate whiskers, aluminum borate whiskers, magnesium sulfate whiskers, zinc oxide whiskers, milled fiber, and cut fiber, as well as granular reinforcing materials. One of these may be used alone, or two or more may be used in combination. Among these, wollastonite, glass fiber, and potassium titanate whiskers are preferred, as they can easily increase the mechanical strength of the resin member, and wollastonite and glass fiber are more preferred.

[0099] The average fiber length of the fibrous reinforcing material is preferably 1 μm or more and 20 mm or less, more preferably 5 μm or more and 10 mm or less, from the viewpoints of moldability of the polyamide resin composition and the mechanical strength and heat resistance of the resulting resin part.

[0100] The cross-sectional shape of the fibrous reinforcing material may be circular or non-circular, but is preferably circular from the viewpoint of increasing the tensile strength of the molded article. When the molded article has a thick portion, the fibers tend to be oriented in the thickness direction of the thick portion, so a circular shape can exert a stronger reinforcing effect (the effect of increasing the tensile strength of the molded article) against cracks that occur inside the thick portion. The above cross-sectional shape can be confirmed by observation with an optical microscope.

[0101] The average fiber length and average fiber diameter of the fibrous reinforcing material can be measured by the following method. 1) The polyamide resin composition is dissolved in a hexafluoroisopropanol / chloroform solution (0.1 / 0.9% by volume), and then filtered to obtain a filtrate. 2) Disperse the filtered material obtained in 1) above in water, and measure the fiber length (Li) and fiber diameter (di) of each of 300 randomly selected fibers using an optical microscope (magnification: 50x). The number of fibers with fiber length Li is taken as qi, and the weight-average length (Lw) is calculated using the following formula, which is the average fiber length of the fibrous reinforcement. Weight average length (Lw) = (Σqi × Li 2 ) / (Σqi×Li) Similarly, the number of fibers with a fiber diameter Di is taken as ri, and the weight average diameter (Dw) is calculated based on the following formula, and this is taken as the average fiber diameter of the fibrous reinforcing material. Weight average diameter (Dw)=(Σri×Di 2 ) / (Σri×Di)

[0102] The content of the reinforcing material is preferably 20% by mass or more and 45% by mass or less, and more preferably 25% by mass or more and 40% by mass or less, based on the total mass of the polyamide resin composition.

[0103] 1-6.Other The mass ratio of the brominated flame retardant (D) to the total mass of the modified polyolefin resin (C) is 120% by mass or more and 2000% by mass or less, preferably 200% by mass or more and 1500% by mass or less, and more preferably 300% by mass or more and 1000% by mass or less. When the ratio is 200% by mass or more, coarsening of the brominated flame retardant (D) in the polyamide resin composition can be further suppressed, thereby further improving reflow heat resistance. Furthermore, when the ratio is 1500% by mass or less, the specific surface area of ​​the brominated flame retardant (D) can be further reduced, thereby further reducing the thermal energy supplied to the molded article when voltage is applied to the molded article. This can further improve the tracking resistance of the molded article.

[0104] The mass ratio of the brominated flame retardant (D) to the total mass of the phosphinic acid compound (B) is 800% by mass or more and 4000% by mass or less, preferably 900% by mass or more and 3000% by mass or less, and more preferably 1000% by mass or more and 2500% by mass or less. When the ratio is 900% by mass or more, the amount of the phosphinic acid compound (B) relative to the brominated flame retardant (D) can be reduced, thereby further suppressing the occurrence of blisters. This can further improve reflow heat resistance. Furthermore, when the ratio is 3000% by mass or less, the amount of the phosphinic acid compound (B) relative to the brominated flame retardant (D) can be increased, thereby further improving tracking resistance.

[0105] 1-7. Method for producing polyamide resin composition The polyamide resin composition can be produced by a known resin mixing method, such as mixing the polyamide resin (A), phosphinic acid compound (B), borate compound (C), and other components as needed, using a Henschel mixer, V-blender, ribbon blender, or tumbler blender, or by melt-kneading the mixed components in a single-screw extruder, multi-screw extruder, kneader, or Banbury mixer, followed by granulation or pulverization. The melting temperature during melt-kneading is preferably at least 10°C above the melting point (Tm) of the polyamide resin (A) and at most 20°C above the melting point (Tm) of the polyamide resin (A).

[0106] The molded article can be produced using the polyamide resin composition by a conventional melt molding method, such as compression molding, injection molding, etc. For example, the polyamide resin composition of the present invention can be put into an injection molding machine whose cylinder temperature is adjusted to the melting point of the polyamide resin (A) or higher, for example, about 280°C to 350°C, to be in a molten state, and then introduced into a mold of a predetermined shape to produce a molded article.

[0107] The shape of the molded article produced using the polyamide resin composition of the present invention is not particularly limited, and may take various shapes depending on the application.

[0108] Examples of applications of molded articles of the polyamide resin composition in this embodiment include vehicle structural parts, vehicle-mounted items, housings for electronic devices, housings for home appliances, structural parts, machine parts, various automobile parts, electronic device parts, medical devices, etc. As described above, the polyamide resin composition can improve the tracking resistance and reflow heat resistance of molded articles, and therefore, among these applications, it can be particularly suitably used for electronic device parts. [Example]

[0109] The present invention will be described below with reference to examples, which should not be construed as limiting the scope of the present invention.

[0110] 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 a 13.6 L autoclave and purged with nitrogen. Stirring was initiated 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 the reaction was continued for 1 hour, the low-order condensation product was discharged into the atmosphere through a spray nozzle installed at the bottom of the autoclave and extracted. The extracted low-order condensation product was cooled to room temperature, then pulverized in a pulverizer to a particle size of 1.5 mm or less, and dried at 110°C for 24 hours.

[0111] Next, this low-order condensate was placed in a tray-type solid-state polymerization reactor, and after nitrogen substitution, the temperature was raised to 220°C over approximately 1 hour and 30 minutes. The low-order condensate was then reacted for 1 hour and cooled to room temperature. Subsequently, polyamide (high condensate) was further melt-polymerized in a twin-screw extruder with a screw diameter of 30 mm and L / D = 36 at a barrel setting temperature of 330°C, a screw rotation speed of 200 rpm, and a resin feed rate of 6 kg / hour to obtain polyamide resin PA-1.

[0112] The resulting polyamide resin PA-1 had an intrinsic viscosity [η] of 0.8 dl / g, a melting point (Tm) of 320°C, a glass transition temperature (Tg) of 95°C, and a heat of fusion (ΔH) of 45 J / g. The composition of the resulting polyamide resin PA-1 was such that, among the dicarboxylic acid-derived component units, the content of terephthalic acid-derived component units was 62.5 mol%, the content of adipic acid-derived component units was 37.5 mol%, and the content of 1,6-diaminohexane-derived component units among the diamine-derived component units was 100 mol%. The ratio of the total number of carbon atoms constituting the aromatic rings to the total number of carbon atoms constituting the component units contained in the polyamide resin PA-1 was 28.1%.

[0113] 1-2. Phosphinic acid compounds (B) Aluminum diethylphosphinate (EXOLIT OP1230, manufactured by Clariant, phosphorus content: 23% by mass (catalog value)) was used.

[0114] 1-3. Modified polyolefin resin (C) Tafmer MH5020 (manufactured by Mitsui Chemicals, Inc.) was used.

[0115] 1-4. Brominated flame retardants (D) Brominated polystyrene (SAY TEX HP-3010G, manufactured by Albemarle Corporation) was used.

[0116] 1-5.Other ingredients 1-5-1. Lubricants Sodium montanate was used.

[0117] 1-5-2. Nucleating agent Talc (average particle size 6 μm) was used.

[0118] 1-5-3.Flame retardant synergists Flame retardant synergist 1: Hydrotalcite (NAOX-33, manufactured by Toda Kogyo Co., Ltd.) Flame retardant synergist 2: anhydrous sodium antimonate (SA-A, manufactured by Nippon Seiko Co., Ltd.)

[0119] 1-5-4. Reinforcement material Glass fiber (ECS03T-262H, manufactured by Nippon Electric Glass Co., Ltd.) was used.

[0120] 1-5-5. Styrene-based thermoplastic elastomer Maleic acid modified styrene-ethylene-butylene-styrene copolymer (m-SEBS) was used.

[0121] 2. Measurement The physical properties of each of the above resins were measured by the following methods.

[0122] <Melting point (Tm), glass transition temperature (Tg)> The melting point (Tm) and glass transition temperature (Tg) of polyamide resin (A) were measured using a differential scanning calorimeter (DSC220C, manufactured by Seiko Instruments Inc.). Specifically, approximately 5 mg of polyamide resin was sealed in an aluminum pan for measurement and set in the differential scanning calorimeter. The polyamide resin was then heated from room temperature to 350°C at 10°C / min. 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, it was heated a second time to 350°C at 10°C / min. The temperature (°C) of the endothermic peak during 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).

[0123] <Heat of fusion (ΔH)> The heat of fusion (ΔH) of the polyamide resin was calculated from the area of ​​the exothermic peak of crystallization during the first heating process in accordance with JIS K 7122 (2012).

[0124] <Intrinsic viscosity [η]> The intrinsic viscosity [η] of the polyamide resin was calculated by dissolving 0.5 g of the polyamide resin in 50 ml of a 96.5% sulfuric acid solution, measuring the flow time of the resulting solution at 25°C ± 0.05°C using an Ubbelohde viscometer, and then calculating the intrinsic viscosity [η] based on the formula: [η] = ηSP / (C(1 + 0.205ηSP)). [η]: Intrinsic viscosity (dl / g) ηSP: Specific viscosity C: Sample concentration (g / dl) t: Number of seconds for sample solution to flow down (seconds) t0: Number of seconds the blank sulfuric acid flows (seconds) ηSP=(t-t0) / t0

[0125] 3. Preparation of polyamide resin composition The above materials were mixed in a tumbler blender in the composition ratios (unit: parts by mass) shown in Table 1, and melt-kneaded using a 30 mmφ vented twin-screw extruder at a cylinder temperature of 300 to 335°C. The kneaded mixture was then extruded into strands and cooled in a water bath. The strands were then taken up in a pelletizer and cut to obtain pellet-shaped polyamide resin compositions 1 to 4.

[0126] 4. Evaluation <Tracking resistance> The obtained polyamide resin composition was molded under the following molding conditions using the following injection molding machine to obtain a test piece of 200 mm x 130 mm x 3 mm. Molding machine: EC75N-2A, manufactured by Toshiba Machine Co., Ltd. Cylinder temperature: Polyamide resin melting point + 10°C Mold temperature: 160℃ Injection setting speed: 100mm / sec

[0127] The comparative tracking index (CTI) [V], which is an index of tracking resistance, was measured for the obtained test piece in accordance with IEC 60112 under the following conditions. Test solution: Ammonium chloride (0.1% concentration) aqueous solution Testing machine: YST-1000V (Yamayo Testing Instruments Co., Ltd.) Test room temperature: 23℃

[0128] The PLC (Performance Level Category) was evaluated based on the measured CTI [V] and the following criteria: 0: CTI is 600V or more 1: CTI is between 400V and 600V 2: CTI is between 250V and 400V 3: CTI is 175V or more and less than 250V 4: CTI is 100V or more and less than 175V 5: CTI is less than 100V

[0129] <Flame retardancy> Each polyamide resin composition was injection molded under the following conditions to prepare 1 / 32 inch x 1 / 2 x 5 inch test pieces. Using the prepared test pieces, a vertical flame test was carried out in accordance with the UL94 standard (UL Test No. UL94 dated June 18, 1991) to evaluate flame retardancy. Molding machine: Tupearl TR40S3A (manufactured by Sodick Plastic Co., Ltd.) Molding machine cylinder temperature: Polyamide resin melting point + 10°C Mold temperature: 120℃

[0130] <Reflow heat resistance temperature> Each polyamide resin composition was injection molded under the following conditions to prepare a test piece having a length of 64 mm, a width of 6 mm and a thickness of 0.8 mm. Molding machine: Tupearl TR40S3A (manufactured by Sodick Plastic Co., Ltd.) Molding machine cylinder temperature: Polyamide resin melting point + 10°C Mold temperature: 100℃

[0131] The prepared test specimens were conditioned at a temperature of 40°C and a relative humidity of 95% for 96 hours. The conditioned test specimens were placed on a 1 mm-thick glass epoxy substrate. A temperature sensor was installed on this substrate. The glass epoxy substrate with the test specimen mounted thereon was set in an air reflow soldering machine (AIS-20-82-C, manufactured by Atec Techtron Co., Ltd.) and subjected to a reflow process according to the temperature profile shown in Figure 1. As shown in Figure 1, the temperature was raised to 230°C at a predetermined rate; then, the temperature was raised to a predetermined set temperature (a in Figure 1 is 255°C, b is 250°C, and c is 245°C) over 20 seconds, and then cooled to 230°C. The maximum set temperature at which the test specimen did not melt and no blisters formed on the surface was determined, and this maximum set temperature was defined as the reflow heat resistance temperature.

[0132] The composition and evaluation results of each polyamide resin composition are shown in Table 1. The composition values ​​in Table 1 represent parts by mass.

[0133] [Table 1]

[0134] The results for polyamide resin composition 1 showed that a polyamide resin composition containing a polyamide resin (A), a phosphinic acid compound (B), a modified polyolefin resin (C), and a brominated flame retardant (D), in which the ratio of the brominated flame retardant (D) to the modified polyolefin resin (C) and the ratio of the brominated flame retardant (D) to the phosphinic acid compound (B) are each within a specific range, can enhance flame retardancy, tracking resistance, and reflow heat resistance.

[0135] In addition, in the polyamide resin composition 4, a styrene-based thermoplastic elastomer was used instead of the modified polyolefin resin (C), but the tracking resistance did not improve. This is thought to be because the styrene-based thermoplastic elastomer has high compatibility with the brominated flame retardant (D), and the specific surface area of ​​the brominated flame retardant (D) could not be reduced.

Claims

1. A polyamide resin composition, a polyamide resin (A) having a melting point of 280°C or higher as measured by a differential scanning calorimeter (DSC); a phosphinic acid compound (B); a polyolefin resin (C) modified with an unsaturated carboxylic acid or a derivative thereof; a brominated flame retardant (D); Including, the ratio of the mass of the brominated flame retardant (D) to the total mass of the polyolefin resin (C) is 120 mass% or more and 2000 mass% or less, The mass ratio of the brominated flame retardant (D) to the total mass of the phosphinic acid compound (B) is 800 mass% or more and 4000 mass% or less. Polyamide resin composition.

2. the content of the phosphinic acid compound (B) is 0.50 mass% or more and 1.50 mass% or less, based on the total mass of the polyamide resin composition; The polyamide resin composition according to claim 1.

3. The content of the polyolefin resin (C) is 1.00 mass% or more and 10.00 mass% or less, based on the total mass of the polyamide resin composition. The polyamide resin composition according to claim 1.

4. The content of the brominated flame retardant (D) is 12.00 mass% or more and 20.00 mass% or less, based on the total mass of the polyamide resin composition. The polyamide resin composition according to claim 1.

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

6. The heat of fusion (ΔH) of the polyamide resin (A) is 30 J / g or more. The polyamide resin composition according to claim 1.

7. The content of phosphorus contained in the phosphinic acid compound (B) is 20% by mass or more and 30% by mass or less, based on the total mass of the phosphinic acid compound (B). The polyamide resin composition according to claim 1.

8. A molded article obtained by molding the polyamide resin composition according to any one of claims 1 to 7.

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