Polyamide resin composition

Abstract

A polyamide resin composition according to the present invention contains a polyamide (A) that has a melting point of at least 280°C, a brominated flame retardant (B), an inorganic filler (C), an aromatic vinyl copolymer (D), and a colorant (E). The polyamide (A) includes diamine units, and 50–100 mol% of the diamine units are C4–18 aliphatic diamine units. For particles of the brominated flame retardant (B) observed in a specific region of a thickness direction cross-section of a test piece that comprises the polyamide resin composition, Rs1 as represented by the expression (bs / as)×As is less than 0.2 μm2. [In the expression, bs / as is the number average value of the ratio of the Feret diameter perpendicular to the minimum Feret diameter of the particles of the brominated flame retardant (B) observed in the specific region, and As is the number average value (μm2) of the cross-sectional area of the particles of the brominated flame retardant (B) observed in the specific area.]

Description

Polyamide resin composition

[0001] The present invention relates to a polyamide resin composition. Specifically, the present invention relates to a polyamide resin composition, a method for producing the polyamide resin composition, and a molded article of the polyamide resin composition.

[0002] Polyamide resins are used in a variety of applications, such as automobile parts and electrical and electronic parts, due to their excellent mechanical properties and heat resistance. Furthermore, polyamide resin compositions may contain a halogen-based flame retardant, such as a bromine-based flame retardant (see Patent Documents 1 to 4). Polyamide resin compositions with enhanced flame retardancy are also referred to as flame-retardant polyamide resin compositions.

[0003] International Publication No. 2020 / 040191 JP 2002-138197 A JP 2000-186206 A JP 2007-291250 A

[0004] When a molded article of a flame-retardant polyamide resin composition (hereinafter also referred to as a "flame-retardant polyamide resin molded article", or sometimes simply referred to as a "molded article") is exposed to high temperatures during a reflow process, the interior or surface of the molded article may swell, i.e., blisters may occur. However, Patent Documents 1 to 4 do not fully consider the blisters.

[0005] Furthermore, the flame-retardant polyamide resin composition may be colored when used for the above-mentioned automotive parts or electric / electronic parts. As a result of investigations by the present inventors, it has been found that the incidence of blistering tends to increase when a molded article of a flame-retardant polyamide resin composition containing a colorant is exposed to high temperatures during a reflow process.

[0006] Therefore, there is a demand for a flame-retardant polyamide resin composition that can give a flame-retardant polyamide resin molded article that has a low rate of blistering even when exposed to high temperatures during the reflow process, that is, has excellent blister resistance.

[0007] Therefore, an object of the present invention is to provide a polyamide resin composition that can give a flame-retardant polyamide resin molded article that has excellent blister resistance even when exposed to high temperatures during a reflow process, a method for producing the polyamide resin composition, and a molded article of the polyamide resin composition.

[0008] As a result of intensive research to solve the above problems, the present inventors have conceived the following invention and found that the above problems can be solved.

[0009] [1] A polyamide resin composition comprising a polyamide (A) having a melting point of 280°C or higher, a brominated flame retardant (B), an inorganic filler (C), an aromatic vinyl copolymer (D), and a colorant (E), wherein the polyamide (A) contains diamine units, and 50 to 100 mol% of the diamine units are aliphatic diamine units having 4 to 18 carbon atoms, and the colorant (E) is at least one of an organic colorant and an inorganic colorant, and wherein when particles of the brominated flame retardant (B) are observed in a region at a depth of 250 μm±8.8 μm from a main surface of a test piece having a length of 30 mm, a width of 10 mm, and a thickness of 1.0 mm, made of the polyamide resin composition, and the region has a width of 25 μm perpendicular to the thickness direction, the number average value As (μm ２ ) is 0.1 μm ２[2] The polyamide resin composition according to claim 1, wherein, when particles of the brominated flame retardant (B) in the region are observed, the product EqD×π (μm), which is the number average value EqD of diameters of perfect circles having the same area as the cross-sectional area of ​​the particles of the brominated flame retardant (B), and pi (μm) is smaller than 1.0 μm. [3] A polyamide resin composition containing a polyamide (A) having a melting point of 280°C or higher, a brominated flame retardant (B), an inorganic filler (C), an aromatic vinyl copolymer (D), and a colorant (E), wherein the polyamide (A) contains diamine units, and 50 to 100 mol% of the diamine units are aliphatic diamine units having 4 to 18 carbon atoms, and the colorant (E) is at least one of an organic colorant and an inorganic colorant, and wherein when particles of the brominated flame retardant (B) are observed in a region at a depth of 250 μm±8.8 μm from a main surface of a test piece having a length of 30 mm, a width of 10 mm, and a thickness of 1.0 mm, made of the polyamide resin composition, and the region has a width of 25 μm perpendicular to the thickness direction, Rs1 (μm ２ ) is 0.2 μm ２ Rs1=(bs / as)×As (1) [In formula (1), bs / as is the number average value of the ratio of the perpendicular Feret diameter to the smallest Feret diameter among the Feret diameters of the particles of the brominated flame retardant (B) observed in the region, and As is the number average value of the cross-sectional area of ​​the particles of the brominated flame retardant (B) observed in the region (μm ２ ).] [4] The polyamide resin composition according to [3], wherein, when particles of the brominated flame retardant (B) are observed in the region, Rs2 (μm) represented by the following formula (2) is smaller than 1.7 μm: Rs2=(bs / as)×EqD×π (2) [In formula (2), bs / as is the number average value of the ratio of the perpendicular Feret diameter to the smallest Feret diameter among the Feret diameters of particles of the brominated flame retardant (B) observed in the region, and EqD is the number average value (μm) of the diameters of perfect circles having the same area as the cross-sectional area of ​​the particles of the brominated flame retardant (B) observed in the region.] [5] The polyamide resin composition according to any of [1] to [4], wherein ΔE represented by the following formula (X) is larger than 1. ...(X) [In formula (X), ΔE is CIE1976(L ＊ a ＊ b ＊ ) is the color difference defined by the color system, and L ＊ ｃｏｌ , a ＊ ｃｏｌ , and b ＊ ｃｏｌ is the CIE1976 (L ＊ a ＊ b ＊ ) L defined by the color system ＊ , a ＊ , and b ＊ and L ＊ ｎａｔ , a ＊ ｎａｔ , and b ＊ ｎａｔ is a CIE1976 (L) of a colorant-free polyamide resin composition having the same composition as the polyamide resin composition except that it does not contain the colorant (E). ＊ a ＊ b ＊ ) L defined by the color system ＊ , a ＊ , and b ＊[6] The polyamide resin composition according to any one of [1] to [5], wherein the organic colorant is at least one selected from the group consisting of anthraquinone dyes, perinone dyes, anthrapyridone dyes, and phthalocyanine dyes. [7] The polyamide resin composition according to any one of [1] to [6], wherein the inorganic colorant is at least one selected from the group consisting of carbon black, metal oxides, metal sulfides, and complex metal oxides. [8] The polyamide resin composition according to any one of [1] to [7], wherein the inorganic colorant is at least one selected from the group consisting of metal oxides, metal sulfides, and complex metal oxides. [9] The polyamide resin composition according to any one of [1] to [8], wherein the colorant (E) comprises the organic colorant, and the content of the organic colorant is 0.0001 to 0.5% by mass, relative to 100% by mass of the polyamide resin composition.

[10] The polyamide resin composition according to any one of [1] to [9], wherein the colorant (E) comprises the inorganic colorant, and the content of the inorganic colorant is 0.001 to 5.0 mass% relative to 100 mass% of the polyamide resin composition.

[11] The polyamide resin composition according to any one of [1] to

[10] , wherein the brominated flame retardant (B) is at least one selected from the group consisting of brominated polystyrene and polybrominated styrene.

[12] The polyamide resin composition according to any one of [1] to

[11] , wherein the polyamide (A) contains dicarboxylic acid units, of which 50 mol % or more are terephthalic acid units, and the aliphatic diamine having 4 to 18 carbon atoms constituting the aliphatic diamine units having 4 to 18 carbon atoms is at least one selected from the group consisting of 1,4-butanediamine, 1,6-hexanediamine, 1,9-nonanediamine, 2-methyl-1,8octanediamine, and 1,10-decanediamine.

[13] The polyamide resin composition according to

[12] , wherein the aliphatic diamine having 4 to 18 carbon atoms is at least one selected from the group consisting of 1,9-nonanediamine and 2-methyl-1,8octanediamine.

[14] The polyamide resin composition according to any one of [1] to

[13] , wherein the aromatic vinyl copolymer (D) contains structural units derived from at least one selected from the group consisting of styrene and α-methylstyrene, and structural units derived from at least one selected from the group consisting of maleic anhydride and monoalkyl maleic anhydrides having an alkyl group containing from 1 to 3 carbon atoms, and wherein the aromatic vinyl copolymer (D) has a glass transition temperature of 120°C or higher.

[15] The polyamide resin composition according to

[14] , wherein the content of structural units derived from at least one selected from the group consisting of maleic anhydride and monoalkyl maleic anhydrides having an alkyl group containing from 1 to 3 carbon atoms in the aromatic vinyl copolymer (D) is 18 to 50 mass%.

[16] The polyamide resin composition according to any one of [1] to

[15] , wherein the weight average molecular weight (Mw) of the aromatic vinyl copolymer (D) is 10,000 to 500,000.

[17] The polyamide resin composition according to any one of [1] to

[16] , further comprising a flame retardant synergist (F).

[18] The polyamide resin composition according to any one of [1] to

[17] , containing, relative to 100 parts by mass of the polyamide (A), 25 to 70 parts by mass of the brominated flame retardant (B), 30 to 250 parts by mass of the inorganic filler (C), 0.1 to 10 parts by mass of the aromatic vinyl copolymer (D), and 0.0005 to 20 parts by mass of the colorant (E).

[19] A method for producing the polyamide resin composition according to any one of [1] to

[18] , comprising melt-kneading the polyamide (A), the brominated flame retardant (B), the inorganic filler (C), the aromatic vinyl copolymer (D), the colorant (E), and, if necessary, a flame retardant aid (F).

[20] A molded article from the polyamide resin composition according to any one of [1] to

[18] .

[21] The molded article according to

[20] , which is a connector.

[22] The molded article according to

[20] or

[21] , which is an in-vehicle connector.

[0010] According to the present invention, it is possible to provide a polyamide resin composition that can give a flame-retardant polyamide resin molded article that has excellent blister resistance even when exposed to high temperatures during a reflow process, a method for producing the polyamide resin composition, and a molded article of the polyamide resin composition.

[0011] Fig. 1 is a partially enlarged view showing a cross section in the thickness direction of test piece C. Fig. 2 is a perspective view of test piece C. Fig. 3 is a photograph showing an SEM image of an analysis region of the test piece of Example 3.

[0012] The following describes an example of an embodiment of the present invention (hereinafter, sometimes referred to as "this embodiment"). However, the embodiment described below is merely an example for embodying the technical concept of the present invention, and the present invention is not limited to the following description. Furthermore, although preferred embodiments are shown in this specification, combinations of two or more of the individual preferred embodiments are also preferred. For matters indicated as numerical ranges, when there are several numerical ranges, the lower and upper limits can be selectively combined to form a preferred embodiment. In this specification, when a numerical range is described as "XX to YY," it means "XX or more and YY or less." Furthermore, in this specification, "units" (where "~" indicates a monomer) mean "structural units derived from ~," for example, "dicarboxylic acid units" mean "structural units derived from dicarboxylic acids," and "diamine units" mean "structural units derived from diamines."

[0013] <Polyamide Resin Composition> A polyamide resin composition according to one embodiment of the present invention is a polyamide resin composition containing a polyamide (A) having a melting point of 280°C or higher, a brominated flame retardant (B), an inorganic filler (C), an aromatic vinyl copolymer (D), and a colorant (E), wherein the polyamide (A) contains diamine units, and 50 to 100 mol% of the diamine units are aliphatic diamine units having 4 to 18 carbon atoms, and the colorant (E) is at least one of an organic colorant and an inorganic colorant, and wherein, when particles of the brominated flame retardant (B) are observed in a region at a specific depth from a main surface of a cross section in the thickness direction of a test piece made of the polyamide resin composition, Rs1 (μm ２ ) is 0.2 μm ２ It is a polyamide resin composition.

[0014] A polyamide resin composition according to one embodiment of the present invention comprises a polyamide (A) having a melting point of 280°C or higher, a brominated flame retardant (B), an inorganic filler (C), an aromatic vinyl copolymer (D), and a colorant (E), wherein the polyamide (A) contains diamine units, and 50 to 100 mol% of the diamine units are aliphatic diamine units having 4 to 18 carbon atoms, and the colorant (E) is at least one of an organic colorant and an inorganic colorant, and when particles of the brominated flame retardant (B) are observed in a region at a specific depth from a main surface of a cross section of a thickness direction of a test piece made of the polyamide resin composition, Rs2 (μm) represented by the above formula (2) is smaller than 1.7 μm.

[0015] A polyamide resin composition according to one embodiment of the present invention is a polyamide resin composition containing a polyamide (A) having a melting point of 280°C or higher, a brominated flame retardant (B), an inorganic filler (C), an aromatic vinyl copolymer (D), and a colorant (E), wherein the polyamide (A) contains diamine units, and 50 to 100 mol% of the diamine units are aliphatic diamine units having 4 to 18 carbon atoms, and the colorant (E) is at least one of an organic colorant and an inorganic colorant, and the number average value As (μm) of the cross-sectional area of ​​particles of the brominated flame retardant (B) observed in a region at a specific depth from a main surface of a cross section in the thickness direction of a test piece made of the polyamide resin composition is ２ ) is 0.1 μm ２ It is a polyamide resin composition.

[0016] A polyamide resin composition according to one embodiment of the present invention comprises a polyamide (A) having a melting point of 280°C or higher, a brominated flame retardant (B), an inorganic filler (C), an aromatic vinyl copolymer (D), and a colorant (E), wherein the polyamide (A) contains diamine units, and 50 to 100 mol% of the diamine units are aliphatic diamine units having 4 to 18 carbon atoms, and the colorant (E) is at least one of an organic colorant and an inorganic colorant, and the polyamide resin composition has a thickness-direction cross section of a test piece made of the polyamide resin composition, and the product EqD×π (μm) of the number average value EqD of the diameters of perfect circles having the same area as the cross-sectional areas of particles of the brominated flame retardant (B), observed in a region at a specific depth from the main surface of the test piece, and pi (π) is less than 1.0 μm.

[0017] The present inventors have found that the tendency of blistering when a flame-retardant polyamide resin molded article is exposed to high temperatures during a reflow process is affected by the state of particles of the brominated flame retardant (B) in the flame-retardant polyamide resin molded article. Based on this finding, the present invention provides a polyamide resin composition that can give a flame-retardant polyamide resin molded article with excellent blister resistance.

[0018] Specifically, in one embodiment of the present invention, when the Rs1 in a test piece made of a polyamide resin composition is smaller than a specific value, a flame-retardant polyamide resin molded product having excellent blister resistance even when exposed to high temperatures during the reflow process can be obtained. Also, in one embodiment of the present invention, when the Rs2 in a test piece made of a polyamide resin composition is smaller than a specific value, a flame-retardant polyamide resin molded product having excellent blister resistance even when exposed to high temperatures during the reflow process can be obtained. In another embodiment of the present invention, when the Rs1 in a test piece made of a polyamide resin composition is smaller than the specific value and the Rs2 is smaller than the specific value, a flame-retardant polyamide resin molded product having excellent blister resistance even when exposed to high temperatures during the reflow process can be more reliably obtained.

[0019] In one embodiment of the present invention, when the As in a test piece made of a polyamide resin composition is smaller than a specific value, a flame-retardant polyamide resin molded article having excellent blister resistance even when exposed to high temperatures during a reflow process can be obtained. Also, in one embodiment of the present invention, when the EqD×π in a test piece made of a polyamide resin composition is smaller than a specific value, a flame-retardant polyamide resin molded article having excellent blister resistance even when exposed to high temperatures during a reflow process can be obtained. In one embodiment of the present invention, when the As in a test piece made of a polyamide resin composition is smaller than the specific value and the EqD×π is smaller than the specific value, a flame-retardant polyamide resin molded article having excellent blister resistance even when exposed to high temperatures during a reflow process can be more reliably obtained.

[0020] The reason why the occurrence of blisters can be suppressed in the present invention from the viewpoint of the state of the brominated flame retardant (B) in the molded article will be explained below, although the present invention is not limited to this explanation.

[0021] First, it is believed that blisters are caused by internal pressure generated by vaporization and expansion of moisture or gas contained in the molded body when exposed to high temperatures. It is said that water vapor is difficult to permeate through the brominated flame retardant (B). Therefore, in the present invention, it was thought that if the particle size of the brominated flame retardant (B) in the molded body is small, when moisture contained in the molded body turns into water vapor inside, a path for the water vapor to escape to the outside is easily secured, thereby suppressing the occurrence of blisters. Another cause of blisters is thought to be that the interface between the polyamide (A) and the brominated flame retardant (B) has weak adhesive strength. For example, stretching or aggregation during the production of the molded body can cause the brominated flame retardant (B) to become coarse, which can then become the starting point for microinterface fractures when internal pressure is generated. In this case, it was thought that by sufficiently reducing the particle size of the brominated flame retardant (B) in the molded body, aggregation of the brominated flame retardant (B) can be suppressed, thereby suppressing the occurrence of blisters.

[0022] The parameters Rs1 and Rs2 will now be described.

[0023] Rs1 is expressed by the following formula (1): Rs1 = (b s / a s) × A s (1) [In formula (1), b s / a s is the number average value of the ratio of the perpendicular Feret diameter to the smallest Feret diameter among the Feret diameters of the particles of the brominated flame retardant (B) observed in the region, and A s is the number average value of the cross-sectional area (μm ２ ) The term "Ferret diameter perpendicular to the minimum Feret diameter" refers to the minimum Feret diameter among 10 Feret diameters measured at 18° intervals in the Feret diameter range from 0 to 162°, and the Feret diameter perpendicular to the minimum Feret diameter.

[0024] As expressed by the above formula, Rs1 is a parameter containing information about the cross-sectional area of ​​the particles of the brominated flame retardant (B) observed in the region. The smaller the value of Rs1, the more likely it is that a molded article with better blister resistance can be obtained. Rs1 is preferably 0.15 μm ２ Less than or equal to 0.1 μm, more preferably 0.1 μm ２ The lower limit of Rs1 is 0 μm. ２ The lower limit of Rs1 is preferably 0.01 μm. ２ More preferably, 0.03 μm or more ２ More preferably, 0.05 μm or more ２ Rs1 can be obtained by performing image analysis on the SEM image using the method described in the examples below.

[0025] Rs2 is expressed by the following formula (2): Rs2 = (bs / as) x EqD x π (2) (In formula (2), bs / as is the number average value (µm) of the ratio of the perpendicular Feret diameter to the smallest Feret diameter among the Feret diameters of the particles of the brominated flame retardant (B) observed in the region, and EqD is the number average value (µm) of the diameter of a perfect circle having the same area as the cross-sectional area of ​​the particles of the brominated flame retardant (B) observed in the region.)

[0026] As represented by the above formula, Rs2 is a parameter including EqD, which is the number average value of the diameters of perfect circles having the same area as the brominated flame retardant (B) observed in the region. The smaller the Rs2 value, the more likely it is that a molded product with better blister resistance can be obtained. In one embodiment of the present invention, Rs2 is preferably 1.6 μm or less, more preferably 1.5 μm or less, even more preferably 1.4 μm or less, even more preferably 1.2 μm or less, and even more preferably 1.1 μm or less. The lower limit of Rs2 is greater than 0 μm. The lower limit of Rs2 is not particularly limited, but is preferably 0.1 μm or more, more preferably 0.3 μm or more, even more preferably 0.5 μm or more, and even more preferably 0.7 μm or more. Rs2 can be calculated from a value obtained by performing image analysis on an SEM image using the method described in the Examples below.

[0027] In one embodiment of the present invention, preferably, Rs1 is 0.2 μm ２ and Rs2 is smaller than 1.7 μm. More preferably, Rs1 is 0.15 μm. ２ and Rs2 is 1.6 μm or less. More preferably, Rs1 is 0.1 μm or less. ２ and Rs2 is 1.5 μm or less.

[0028] The parameters As and EqD×π will be described.

[0029] As contains information about the cross-sectional area of ​​the particles of the brominated flame retardant (B), and is the number average value (μm ２ As can be obtained by performing image analysis on an SEM image by the method described in the examples below.

[0030] The smaller the As value, the more likely it is that a molded article having better blister resistance can be obtained. In one embodiment of the present invention, As is preferably 0.075 μm ２ or less, more preferably 0.06 μm ２ or less, and more preferably 0.05 μm２ The lower limit of As is 0 μm. ２ More than 0.005 μm, preferably ２ More preferably, it is 0.01 μm or more. ２ More preferably, it is 0.03 μm or more. ２ That's all.

[0031] EqD in EqD × π is the number average value of the diameters of perfect circles having the same area as the cross-sectional area of ​​the particles of the brominated flame retardant (B) observed in the region. EqD × π is a parameter containing information about the circumference of a perfect circle having the same area as the cross-sectional area of ​​the particles of the brominated flame retardant (B) observed in the region. EqD can be obtained by performing image analysis on the SEM image using the method described in the Examples below.

[0032] The smaller the value of EqD×π, the more likely it is that a molded product with better blister resistance can be obtained. In one embodiment of the present invention, EqD×π is preferably 0.9 μm or less, more preferably 0.8 μm or less, and even more preferably 0.7 μm or less. The lower limit of EqD×π is greater than 0 μm. The lower limit of EqD×π is not particularly limited, but is preferably, for example, 0.1 μm or more, more preferably 0.2 μm or more, even more preferably 0.3 μm or more, and even more preferably 0.5 μm or more.

[0033] In one embodiment of the present invention, As is preferably 0.1 μm ２ and EqD×π is smaller than 1.0 μm. More preferably, As is 0.075 μm. ２ or less, and EqD×π is smaller than 1.0 μm. More preferably, As is 0.075 μm. ２ and EqD×π is 0.8 μm or less.

[0034] A test piece C made of a polyamide resin composition will now be described. FIG. 1 is a partially enlarged view showing a thickness direction cross section of the test piece C made of a polyamide resin composition. In FIG. 1, the up-down direction indicates the T direction (thickness direction), and the left-right direction indicates the W direction (width direction). The test piece C may be obtained by molding a polyamide resin composition, or may be cut out from a molded product of the polyamide resin composition. In FIG. 1, the top surface of the test piece C is the main surface. This main surface is set as the starting point (0 μm), and the position (distance) within the test piece C in the T direction from this main surface is referred to as the depth. FIG. 2 is a perspective view of the test piece C made of a polyamide resin composition. In addition to the T and W directions, the L direction (length direction) is also shown in FIG. 2. The test piece C has a length of 30 mm, a width of 10 mm, and a thickness of 1.0 mm to standardize the size. When the test piece C has a length of 30 mm, a width of 10 mm, and a thickness of 1.0 mm, from the viewpoint of standardizing the cutting position, the thickness direction cross section of the test piece C is preferably a plane parallel to the width direction and located 1.0 mm (=0.1 cm) from one end in the L direction (length direction) of the test piece C, as shown in Fig. 2. When the test piece C is obtained by injection molding, it is more preferable to adopt, as the one end in the length direction of the test piece C, an end that corresponds to the upstream side (gate side) of the macroscopic resin flow direction during injection molding.

[0035] In this embodiment, the specific region is a region (hereinafter also referred to as the "surface region") that is 250 μm±8.8 μm deep from the main surface of a test piece C made of a polyamide resin composition, measuring 30 mm in length, 10 mm in width, and 1.0 mm in thickness, in a cross section in the thickness direction of the test piece C, and has a width of 25 μm perpendicular to the thickness direction of the test piece C (the region surrounded by a dashed line in FIG. 1). Note that 250 μm±8.8 μm means 241.2 to 258.8 μm. From the viewpoint of uniform positioning, it is preferable that the midpoint of the width perpendicular to the thickness direction of the surface region of the test piece C is the center position in the width direction of the test piece C. In other words, the surface region is preferably a region in the thickness direction cross section of a test piece C made of a polyamide resin composition, measuring 30 mm in length, 10 mm in width, and 1.0 mm in thickness, that is 250 μm ± 8.8 μm deep from the main surface of the test piece C, and that has a width of 25 μm perpendicular to the thickness direction, with the center position in the width direction of the test piece C as the midpoint. This allows information about the cross-sectional area of ​​the particles of brominated flame retardant (B) in the surface region of the test piece to be obtained. The main surface of the test piece serves as the starting point for the depth. When the test piece C is obtained by injection molding, from the viewpoint of unifying the starting point in the thickness direction, it is preferable to use a surface (the so-called upper surface) that is vertically above the macroscopic resin flow direction during injection molding as the main surface. Furthermore, when the test piece C is cut out from a molded product of the polyamide resin composition, it is preferable to cut out the test piece C so as to include the surface of the molded product, and to use this surface as the main surface.

[0036] In the surface layer region, the smaller the particles of the brominated flame retardant (B), the more likely it is that the occurrence of blisters can be suppressed. Therefore, in the resin composition according to one embodiment of the present invention, the number average value As (μm ) of the cross-sectional area of ​​the particles of the brominated flame retardant (B) observed in the surface layer region in the formula (1) is ２ ) is 0.10 μm ２ Preferably, it is less than 0.09 μm ２ More preferably, it is 0.08 μm or less. ２ More preferably, it is 0.06 μm or less. ２ Even more preferably, it is 0.05 μm or less. ２It is even more preferable that the number average value As of the cross-sectional area is equal to or less than 1.0, as described above, the value of the number average value As of the cross-sectional area can be obtained by performing image analysis on the SEM image by the method described in the examples below.

[0037] Since the smaller the particles of the brominated flame retardant (B) in the surface region, the more likely it is that blister formation can be suppressed, in the resin composition according to one embodiment of the present invention, the number average diameter EqD of the perfect circle having the same area as the particles of the brominated flame retardant (B) observed in the surface region in the formula (2) is preferably 0.40 μm or less, more preferably 0.35 μm or less, even more preferably 0.31 μm or less, and even more preferably 0.22 μm or less. As mentioned above, the number average diameter EqD (μm) can be obtained as the value of EqD by performing image analysis on SEM images by the method described in the Examples below.

[0038] In this embodiment, Rs1 and Rs2 both contain information about the Feret diameter, specifically (bs / as). Information about the Feret diameter, specifically (bs / as) can be obtained by performing image analysis on the SEM image using the method described in the examples below.

[0039] The Feret diameter usually refers to the distance between two parallel tangents along a predetermined direction of a particle of the image analysis target (also simply referred to as "object"). In image analysis, the minimum Feret diameter can be identified from the obtained Feret diameters by changing the angle in 18° increments, with the horizontal direction of the image being 0°. In this embodiment, the Feret diameter is a two-dimensional Feret diameter because the above-mentioned path in the thickness direction cross section of the test piece is taken into consideration.

[0040] When observing the surface region of the test piece C, a scanning electron microscope (SEM) is preferably used, and a field emission scanning electron microscope (FE-SEM) is more preferable. In addition, it is preferable to perform image analysis on the obtained image, and it is preferable to use "Avizo 3D" manufactured by Thermo Fisher Scientific as software for image analysis.

[0041] When the brominated flame retardant (B) is blended with other components and subjected to shearing during melt kneading or injection molding, its average diameter usually decreases. On the other hand, during the cooling process after injection molding, the brominated flame retardant (B) may aggregate or be affected by internal stress (for example, pressure in the resin flow direction and stress due to fluctuations in the arrangement direction of the inorganic filler (C)), causing the particles of the brominated flame retardant (B) to assume a shape elongated along the stressed direction. Therefore, when observed in cross section, the number average value of bs / as of the particles of the brominated flame retardant (B) contained in the molded product of the polyamide resin composition of this embodiment tends to be greater than 1, specifically 1.4 or more. Furthermore, when observed in cross section, the As and EqD×π of the particles of the brominated flame retardant (B) contained in the molded product of the polyamide resin composition of this embodiment tend to be large values.

[0042] However, even when the bs / as of a particle of the brominated flame retardant (B) is 1.4 or more, if the particle size is sufficiently small, it is unlikely that the particle will significantly obstruct the aforementioned pathway or become a micro-fracture initiation point. Therefore, in one embodiment of the present invention, the cross-sectional area of ​​a particle of the brominated flame retardant (B) present in a specific region is expressed by the above formula (1). The reason for multiplying bs / as by the cross-sectional area in formula (1) is that the more the flame retardant is stretched, the greater the possibility of gas diffusion obstruction or becoming a micro-fracture initiation point. Similarly, in one embodiment of the present invention, the circumference of a perfect circle having the same area as the cross-sectional area of ​​a particle of the brominated flame retardant (B) present in a specific region is expressed as EqD×π, and the expression is given by the above formula (2). The reason for multiplying bs / as by EqD×π in formula (2) is that the more the flame retardant is stretched, the greater the possibility of gas diffusion obstruction or becoming a micro-fracture initiation point. The above-mentioned problem can be solved by making Rs1 and Rs2, which are values ​​obtained from these equations, smaller than the above-mentioned specific values.

[0043] In this embodiment, even if the particles of the brominated flame retardant (B) have an elongated shape, if the particle size is sufficiently small, they are unlikely to significantly obstruct the aforementioned path or become tiny fracture origins. Therefore, in one embodiment of the present invention, the cross-sectional area of ​​the particles of the brominated flame retardant (B) present in a specific region is expressed as As. Similarly, in one embodiment of the present invention, the circumference of a perfect circle having the same area as the cross-sectional area of ​​the particles of the brominated flame retardant (B) present in a specific region is expressed as EqD × π. When these values ​​are smaller than a specific value, the aforementioned problem can be solved.

[0044] Each component of the polyamide resin composition of this embodiment will be described below.

[0045] [Polyamide (A)] The polyamide (A) used in this embodiment has a melting point of 280°C or higher and contains diamine units. The diamine units contain 50 to 100 mol% aliphatic diamine units having 4 to 18 carbon atoms. By containing 50 to 100 mol% aliphatic diamine units having 4 to 18 carbon atoms, a molded product with excellent blister resistance can be obtained even when exposed to high temperatures during the reflow process. The content of aliphatic diamine units having 4 to 18 carbon atoms in the diamine units is preferably 75 to 100 mol%, more preferably 85 to 100 mol%. Polyamide (A) may be one type or two or more types.

[0046] Examples of the aliphatic diamine having 4 to 18 carbon atoms that constitutes the aliphatic diamine unit having 4 to 18 carbon atoms include linear aliphatic diamines such as 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine, and 1,12-dodecanediamine; 1-butyl-1,2-ethanediamine, 1,1-dimethyl-1,4-butanediamine, and 1-ethyl-1,4-butanediamine; hexanediamine, 1,2-dimethyl-1,4-butanediamine, 1,3-dimethyl-1,4-butanediamine, 1,4-dimethyl-1,4-butanediamine, 2,3-dimethyl-1,4-butanediamine, 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 2,5-dimethyl-1,6-hexanediamine, 2,4-dimethyl-1,6-hexanediamine, 3,3-dimethyl-1,6-hexanediamine, 2,2-dimethyl-1,6-hexanediamine, 2,2,4-trimethyl-1,6- Hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 2-propyl-1,6-hexanediamine, 2,4-diethyl-1,6-hexanediamine, 2,2-dimethyl-1,7-heptanediamine, 2,3-dimethyl-1,7-heptanediamine, 2,4-dimethyl-1,7-heptanediamine, 2,5-dimethyl-1,7-heptanediamine, 2-ethyl-1,7-heptanediamine, 2-methyl-1,8-octanediamine, 3-methyl-1,8-octanediamine, 4-methyl- Examples of branched chain aliphatic diamines include 1,8-octanediamine, 1,3-dimethyl-1,8-octanediamine, 1,4-dimethyl-1,8-octanediamine, 2,4-dimethyl-1,8-octanediamine, 3,4-dimethyl-1,8-octanediamine, 4,5-dimethyl-1,8-octanediamine, 2,2-dimethyl-1,8-octanediamine, 3,3-dimethyl-1,8-octanediamine, 4,4-dimethyl-1,8-octanediamine, and 5-methyl-1,9-nonanediamine.Among these, from the viewpoint of excellent physical properties such as heat resistance and low water absorbency, at least one selected from the group consisting of 1,4-butanediamine, 1,6-hexanediamine, 1,9-nonanediamine, 2-methyl-1,8 octanediamine, and 1,10-decanediamine is preferred, at least one selected from the group consisting of 1,9-nonanediamine, 2-methyl-1,8 octanediamine, and 1,10-decanediamine is more preferred, at least one selected from the group consisting of 1,9-nonanediamine and 2-methyl-1,8-octanediamine is even more preferred, and a combined use of 1,9-nonanediamine and 2-methyl-1,8-octanediamine is even more preferred.

[0047] When 1,9-nonanediamine and 2-methyl-1,8-octanediamine are used in combination as the aliphatic diamine having 4 to 18 carbon atoms, from the viewpoint of heat resistance, the molar ratio of 1,9-nonanediamine to 2-methyl-1,8-octanediamine (1,9-nonanediamine / 2-methyl-1,8-octanediamine) is preferably in the range of 95 / 5 to 40 / 60, more preferably in the range of 90 / 10 to 50 / 50, and even more preferably in the range of 90 / 10 to 60 / 40.

[0048] The polyamide (A) may contain diamine units other than the aliphatic diamine units having 4 to 18 carbon atoms. Examples of diamines constituting such other diamine units include aliphatic diamines having 2 or 3 carbon atoms, aromatic diamines, and alicyclic diamines. Examples of aliphatic diamines having 2 or 3 carbon atoms include ethylenediamine, 1,2-propanediamine, and 1,3-propanediamine. Examples of aromatic diamines include p-phenylenediamine, m-phenylenediamine, p-xylylenediamine, m-xylylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, and 4,4'-diaminodiphenyl ether. Examples of alicyclic diamines include cyclohexanediamine, methylcyclohexanediamine, isophoronediamine, norbornanedimethylamine, and tricyclodecanedimethylamine. These diamines can be used alone or in combination. The polyamide (A) may further contain a structural unit derived from a trivalent or higher polyvalent amine such as bis(hexamethylene)triamine, to the extent that melt molding is possible, as long as the effects of the present invention are not impaired.

[0049] When the polyamide (A) contains other diamine units, the content thereof is preferably 50 mol % or less, more preferably 30 mol % or less, even more preferably 20 mol % or less, and still more preferably 10 mol % or less, of the total diamine units constituting the polyamide (A).

[0050] The polyamide (A) contains any dicarboxylic acid unit. Examples of the dicarboxylic acid constituting the dicarboxylic acid unit include aliphatic dicarboxylic acids such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, dimethylmalonic acid, 2,2-diethylsuccinic acid, 2,2-dimethylglutaric acid, 2-methyladipic acid, and trimethyladipic acid; 1,3-cyclopentanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, and cycloheptanedicarboxylic acid. Examples of suitable dicarboxylic acids include alicyclic dicarboxylic acids such as cyclooctanedicarboxylic acid, cyclodecanedicarboxylic acid, and the like; and aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,4-phenylenedioxydiacetic acid, 1,3-phenylenedioxydiacetic acid, diphenic acid, diphenylmethane-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, and 4,4'-biphenyldicarboxylic acid. These dicarboxylic acids can be used alone or in combination. The polyamide (A) may contain structural units derived from polycarboxylic acids, as long as the effects of the present invention are not impaired. Examples of structural units derived from polycarboxylic acids include trimellitic acid, trimesic acid, and pyromellitic acid. It is preferable to contain such structural units to the extent that melt molding is possible.

[0051] The dicarboxylic acid units preferably contain terephthalic acid units at 50 mol% or more, more preferably 60 mol% or more, even more preferably 75 mol% or more, and may even contain 100 mol%. When the dicarboxylic acid units contain terephthalic acid units at 50 mol% or more, a molded product with improved blister resistance can be obtained even when exposed to high temperatures during a reflow process. In one aspect, the polyamide (A) contains dicarboxylic acid units, and in the polyamide (A), 50 mol% or more of the dicarboxylic acid units are terephthalic acid units, and the aliphatic diamine having 4 to 18 carbon atoms constituting the aliphatic diamine units having 4 to 18 carbon atoms is at least one selected from the group consisting of 1,4-butanediamine, 1,6-hexanediamine, 1,9-nonanediamine, 2-methyl-1,8octanediamine, and 1,10-decanediamine.

[0052] The molar ratio of dicarboxylic acid units to diamine units in the polyamide (A) [dicarboxylic acid units / diamine units] is preferably 45 / 55 to 55 / 45, and more preferably 47 / 53 to 53 / 47, from the viewpoint of increasing the degree of polymerization. The molar ratio of dicarboxylic acid units to diamine units can be adjusted depending on the blending ratio (molar ratio) of the raw dicarboxylic acid and the raw diamine. The total content of dicarboxylic acid units and diamine units in 100 mol% of the polyamide (A) is preferably 80 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and even more preferably 99 mol% or more, and may even be 100 mol%.

[0053] It is preferable that 10% or more of the terminal groups of the molecular chain of the polyamide (A) are blocked with a terminal blocking agent. The proportion of the terminal groups of the molecular chain blocked with the terminal blocking agent (terminal blocking rate) is more preferably 20% or more. As the terminal blocking agent, a monofunctional compound reactive with the amino or carboxyl group at the polyamide terminal can be used. From the viewpoints of reactivity and the stability of the blocked terminal, a monocarboxylic acid or a monoamine is preferred, and from the viewpoint of ease of handling, a monocarboxylic acid is more preferred. Other terminal blocking agents that can be used include monoisocyanates, monoacid halides, monoesters, and monoalcohols.

[0054] The monocarboxylic acid used as the end-capping agent may be one that is reactive with an amino group, and examples thereof include aliphatic monocarboxylic acids such as acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, pivalic acid, and isobutyric acid; alicyclic monocarboxylic acids such as cyclohexanecarboxylic acid; aromatic monocarboxylic acids such as benzoic acid, toluic acid, α-naphthalenecarboxylic acid, β-naphthalenecarboxylic acid, methylnaphthalenecarboxylic acid, and phenylacetic acid; and any mixtures thereof. Among these, from the viewpoints of reactivity, stability of the blocked end, cost, and the like, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, lauric acid, tridecanoic acid, myristic acid, palmitic acid, stearic acid, and benzoic acid are preferred.

[0055] The monoamine used as the terminal blocking agent may be one that is reactive with a carboxyl group, and examples thereof include aliphatic monoamines such as methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, decylamine, stearylamine, dimethylamine, diethylamine, dipropylamine, and dibutylamine; alicyclic monoamines such as cyclohexylamine and dicyclohexylamine; aromatic monoamines such as aniline, toluidine, diphenylamine, and naphthylamine; and any mixtures thereof. Among these, butylamine, hexylamine, octylamine, decylamine, stearylamine, cyclohexylamine, and aniline are preferred from the standpoints of reactivity, boiling point, stability of the blocked terminals, cost, and the like.

[0056] The terminal capping rate of polyamide (A) is calculated by measuring the number of carboxyl terminals, amino terminals, and terminal groups capped with a terminal capping agent present in polyamide (A) and then calculating the terminal capping rate according to the following formula (I): １ It is preferable to determine the terminal capping rate from the integrated value of the characteristic signal corresponding to each terminal group by H-NMR: Terminal capping rate (%) = [(T - S) / T] x 100 (I) (where T represents the total number of terminal groups in the molecular chain of polyamide (A) (this is usually equal to twice the number of polyamide molecules), and S represents the total number of carboxyl terminals and amino terminals that remain uncapped.)

[0057] The polyamide (A) can be produced by any known method for producing crystalline polyamides, such as a solution polymerization method or an interfacial polymerization method using dicarboxylic acid and diamine in the form of acid chloride as raw materials, a melt polymerization method, a solid-state polymerization method, or a melt extrusion polymerization method using dicarboxylic acid and diamine as raw materials.

[0058] The melting point of polyamide (A) is 280°C or higher, preferably 290°C or higher, more preferably 300°C or higher, from the viewpoint of heat resistance and the effects of the present invention being more pronounced. Furthermore, from the viewpoint of suppressing thermal decomposition of the polyamide during melt molding, it is preferably 350°C or lower, more preferably 340°C or lower, and even more preferably 330°C or lower. When two or more polyamides are used, the melting point of polyamide (A) being 280°C or higher means that the melting point calculated as a weighted average based on the melting points of each polyamide and the content (mass%) of each polyamide relative to 100% by mass of the total polyamide is 280°C or higher. The melting point of polyamide (A) can be determined using a differential scanning calorimetry (DSC) analyzer as the peak temperature of an endothermic peak that appears when the temperature is increased at a rate of 10°C / min.

[0059] From the viewpoint of heat resistance, the glass transition temperature of the polyamide (A) is preferably 100°C or higher, more preferably 110°C or higher, and even more preferably 120°C or higher. There is no particular upper limit to the glass transition temperature of the polyamide (A), but from the viewpoint of handleability, it is preferably 180°C or lower, more preferably 160°C or lower, and may be 150°C or lower. In other words, the glass transition temperature of the polyamide (A) is preferably 100 to 180°C, more preferably 110 to 160°C, and even more preferably 120 to 150°C. The glass transition temperature of the polyamide (A) can be determined using a differential scanning calorimetry (DSC) analyzer as the temperature of the inflection point that appears when the temperature is increased at a rate of 20°C / min.

[0060] The content (mass%) of polyamide (A) in the total amount of the polyamide resin composition of this embodiment is preferably 20 to 70 mass%, more preferably 25 to 70 mass%, even more preferably 30 to 65 mass%, and still more preferably 30 to 50 mass%, from the viewpoint of exhibiting the mechanical properties and heat resistance that polyamide has.

[0061] [Brominated Flame Retardant (B)] The polyamide resin composition of this embodiment contains a brominated flame retardant (B). By containing the brominated flame retardant (B), the polyamide resin composition has improved flame retardancy.

[0062] Examples of the brominated flame retardant (B) used in this embodiment include hexabromocyclododecane, decabromodiphenyl oxide, octabromodiphenyl oxide, tetrabromobisphenol A, bis(tribromophenoxy)ethane, bis(pentabromophenoxy)ethane, tetrabromobisphenol A epoxy resin, tetrabromobisphenol A carbonate, ethylene(bistetrabromophthal)imide, ethylenebispentabromodiphenyl, tris(tribromophenoxy)triazine, bis(dibromopropyl)tetrabromobisphenol Examples of the brominated polystyrene include brominated polyphenylene ethers such as brominated phenol A, bis(dibromopropyl)tetrabromobisphenol S, and poly(di)bromophenylene ether; polydibromostyrene; polytribromostyrene; brominated polystyrene; polybrominated styrene; brominated crosslinked aromatic polymers; brominated epoxy resins; brominated phenoxy resins; brominated styrene-maleic anhydride polymers; tetrabromobisphenol S; tris(tribromoneopentyl)phosphate; polybromotrimethylphenylindane; and tris(dibromopropyl)isocyanurate. Examples of the brominated polystyrene include uncrosslinked and unmodified brominated polystyrene, crosslinked brominated polystyrene, and modified brominated polystyrene to which a functional group has been added. Examples of the functional group include functional groups containing an epoxy group, such as glycidyl methacrylate, and acid anhydride groups containing α,β-unsaturated dicarboxylic acid anhydrides, such as maleic anhydride and citraconic anhydride. The modification rate is preferably 0.1 to 20% by mass, more preferably 0.5 to 10% by mass. Similarly, the polybrominated styrene may be unmodified polybrominated styrene or modified polybrominated styrene to which a functional group has been added. The functional group and modification rate in the modified polybrominated styrene are the same as those described above for the modified brominated polystyrene. These brominated flame retardants (B) may be used alone or in combination of two or more.The brominated flame retardant (B) preferably contains at least one selected from the group of brominated polystyrenes and the group of polybrominated styrenes, more preferably contains one selected from the group of brominated polystyrenes and one selected from the group of polybrominated styrenes, and even more preferably contains a modified brominated polystyrene to which a functional group has been added and one selected from the group of polybrominated styrenes.

[0063] Brominated polystyrene can be produced, for example, by polymerizing a styrene monomer to produce polystyrene, and then brominating the benzene ring of the polystyrene. Polybrominated styrene can be produced by polymerizing a brominated styrene monomer (bromostyrene, dibromostyrene, tribromostyrene, etc.).

[0064] The bromine content in both the brominated polystyrene and the polybrominated styrene is preferably 55 to 75% by mass, more preferably 55 to 70% by mass. By setting the bromine content to 55% by mass or more, the amount of bromine required for flame retardancy can be satisfied with a small content of the brominated polystyrene and the polybrominated styrene, and deterioration of mechanical properties can be suppressed, resulting in a molded article with excellent mechanical properties and heat resistance. Furthermore, by setting the bromine content to 75% by mass or less, thermal decomposition during melt processing such as extrusion or molding is unlikely to occur, gas generation can be suppressed, and a molded article with excellent heat discoloration resistance can be obtained.

[0065] The content (mass %) of the brominated flame retardant (B) in the total amount of the polyamide resin composition of this embodiment is preferably 10 to 40 mass %, more preferably 12 to 35 mass %, and even more preferably 15 to 30 mass %, from the viewpoint of obtaining a molded article having excellent flame retardancy.

[0066] The content of the brominated flame retardant (B) is preferably 25 to 70 parts by mass, more preferably 30 to 65 parts by mass, and even more preferably 35 to 60 parts by mass, per 100 parts by mass of the polyamide (A). When the content of the brominated flame retardant (B) is 25 parts by mass or more, a molded article with excellent flame retardancy can be obtained. Furthermore, when the content of the brominated flame retardant (B) is 70 parts by mass or less, a molded article with excellent blister resistance, flame retardancy, and mechanical properties can be obtained, even when exposed to high temperatures during the reflow process. When multiple types of brominated flame retardants (B) are used, the total amount thereof should be within the above range.

[0067] [Inorganic Filler (C)] The polyamide resin composition of this embodiment contains an inorganic filler (C). Examples of the inorganic filler (C) include carbon nanotubes, fullerenes, talc, wollastonite, zeolite, sericite, mica, kaolin, clay, pyrophyllite, silica, bentonite, alumina silicate, silicon oxide, magnesium oxide, alumina, magnesium carbonate, dolomite, calcium sulfate, calcium hydroxide, magnesium hydroxide, milled fiber, glass powder, ceramic beads, boron nitride, silicon carbide, various clay minerals such as halloysite and vermiculite, and glass fiber. These inorganic fillers (C) may be used alone or in combination of two or more. From the viewpoint of improving the mechanical properties of a molded article of the polyamide resin composition, the inorganic filler (C) preferably contains glass fiber or wollastonite, more preferably contains glass fiber (C1), and even more preferably is glass fiber (C1).

[0068] The glass fiber (C1) preferably has the following properties. The average fiber length of the glass fiber (C1) is preferably 1 to 10 mm, more preferably 1 to 7 mm, and even more preferably 2 to 4 mm. The average fiber diameter of the glass fiber (C1) is preferably 6 to 20 μm, more preferably 6 to 15 μm, from the viewpoint of obtaining a molded product with superior blister resistance and mechanical properties. It is known that the smaller the average fiber diameter of the glass fiber (C1), the better the blister resistance. However, in the present invention, glass fibers (C1) with a relatively large average fiber diameter can also be used. Therefore, the average fiber diameter of the glass fiber (C1) is more preferably 9 to 13 μm, and even more preferably 10 to 12 μm. The average fiber length and average fiber diameter of the glass fiber (C1) can be determined by measuring the fiber length and fiber diameter of 400 arbitrarily selected glass fibers (C1) through image analysis using an electron microscope and calculating the respective average values. The average fiber length and average fiber diameter of the glass fibers (C1) in the polyamide resin composition or the molded article can be determined, for example, by dissolving the polyamide resin composition or the molded article in an organic solvent, extracting the glass fibers (C1), and performing image analysis using an electron microscope in the same manner as described above.

[0069] Examples of the cross-sectional shape of the glass fiber (C1) include a round (circular), rectangular, oval close to a rectangle, ellipse, cocoon shape, a cocoon shape with a narrowed central portion in the longitudinal direction, etc. Among these, the cross-sectional shape of the glass fiber (C1) is preferably a round (circular), rectangular, oval close to a rectangle, ellipse, or cocoon shape, and more preferably a round (circular) shape.

[0070] The glass fiber (C1) may contain at least one surface treatment agent selected from the group consisting of a coupling agent and a sizing agent. For example, the glass fiber (C1) may contain a sizing agent. The glass fiber (C1) may also contain a coupling agent and a sizing agent. The glass fiber (C1) preferably contains a surface treatment agent on its surface. The amount of the surface treatment agent attached is usually preferably 0.01 mass% or more relative to the total mass of the glass fiber (C1) (i.e., the total amount of the glass fiber (C1) and the surface treatment agent). From the viewpoint of blister resistance, it is preferably 0.01 mass% or more and 2.0 mass% or less, more preferably 0.2 mass% or more and 0.9 mass% or less, and even more preferably 0.3 mass% or more and 0.5 mass% or less.

[0071] Examples of the coupling agent include silane coupling agents and titanium coupling agents, such as γ-methacryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-aminopropyltriethoxysilane.

[0072] Examples of sizing agents include urethane resin-based sizing agents, acrylic resin-based sizing agents, epoxy resin-based sizing agents, and acid anhydride group-containing resin-based sizing agents. However, when a urethane resin-based sizing agent, an acrylic resin-based sizing agent, or an epoxy resin-based sizing agent contains an acid anhydride group, it is considered to belong to the category of acid anhydride group-containing resin-based sizing agents. The acid anhydride group-containing resin-based sizing agent is composed of a resin containing at least an acid anhydride group, and preferably a copolymer containing an acid anhydride group. From the viewpoint of obtaining a molded product with better blister resistance and better mechanical properties, it is preferable that the sizing agent contains at least one selected from the group consisting of epoxy resin-based sizing agents and acid anhydride group-containing resin-based sizing agents. From the viewpoint of obtaining a molded product with even better blister resistance, it is preferable that the sizing agent contains an epoxy resin-based sizing agent. From the viewpoint of obtaining a molded product with even better fluidity, it is preferable that the sizing agent contains a urethane resin-based sizing agent. It is believed that selecting an appropriate surface treatment agent for the glass fiber (C1) contributes to imparting to the molded article strength that can withstand the internal pressure of water vapor even under the peak temperature conditions of the reflow process.

[0073] The content of the inorganic filler (C) is preferably 30 to 250 parts by mass, more preferably 35 to 200 parts by mass, even more preferably 40 to 150 parts by mass, and still more preferably 45 to 100 parts by mass, relative to 100 parts by mass of the polyamide (A). When the content of the inorganic filler (C) is 30 parts by mass or more, a molded product with more excellent mechanical properties can be obtained, and when the content is 250 parts by mass or less, shear heat generation during melt-kneading can be suppressed.

[0074] [Aromatic vinyl copolymer (D)] The polyamide resin composition of this embodiment contains an aromatic vinyl copolymer (D) (hereinafter also referred to as "copolymer (D)") from the viewpoint of obtaining a flame-retardant polyamide resin molded article having excellent blister resistance. This makes it possible to reduce Rs1 represented by the above-mentioned formula (1) to 0.2 μm ２ In one embodiment of the present invention, the aforementioned As can be maintained at a value smaller than 0.1 μm. ２ Furthermore, in one embodiment of the present invention, the aforementioned EqD×π can be made smaller than 1.0 μm. This can be understood from a comparison between the Examples and Comparative Examples illustrated in the Examples section. One of the factors that contribute to such an effect of copolymer (D) is thought to be that copolymer (D) improves the compatibility between the components in the polyamide resin composition, thereby suppressing the aggregation of particles of brominated flame retardant (B), which tends to occur during cooling.

[0075] From the viewpoints of flame retardancy, heat resistance, and moldability, the copolymer (D) preferably contains a structural unit derived from at least one selected from the group consisting of styrene and α-methylstyrene, and a structural unit derived from at least one selected from the group consisting of maleic anhydride and a monoalkyl maleic anhydride having an alkyl group having 1 to 3 carbon atoms, and more preferably contains a structural unit derived from styrene and a structural unit derived from maleic anhydride.

[0076] The content of structural units derived from at least one selected from the group consisting of maleic anhydride and monoalkyl maleic anhydride having an alkyl group having 1 to 3 carbon atoms in the copolymer (D) is preferably 3 to 50 mass%, more preferably 5 to 50 mass%, even more preferably 18 to 50 mass%, and still more preferably 18 to 45 mass%, from the viewpoints of flame retardancy, heat resistance, and moldability.

[0077] Copolymer (D) may further contain structural units other than structural units derived from at least one selected from the group consisting of styrene and α-methylstyrene, and structural units derived from at least one selected from the group consisting of maleic anhydride and a monoalkyl maleic anhydride having an alkyl group having 1 to 3 carbon atoms. The total content of structural units derived from at least one selected from the group consisting of styrene and α-methylstyrene, and structural units derived from at least one selected from the group consisting of maleic anhydride and a monoalkyl maleic anhydride having an alkyl group having 1 to 3 carbon atoms in copolymer (D) is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 100% by mass.

[0078] The glass transition temperature of copolymer (D) is preferably 120°C or higher, more preferably 120 to 200°C, even more preferably 125 to 180°C, and still more preferably 125 to 160°C. When the glass transition temperature of copolymer (D) is 120°C or higher, the flame retardancy and heat resistance can be further improved, and when it is 200°C or lower, thermal decomposition of polyamide during melt molding can be suppressed. The glass transition temperature of copolymer (D) can be determined as the temperature of the inflection point that appears when the temperature is increased at a rate of 20°C / min using a differential scanning calorimetry (DSC) analyzer.

[0079] From the viewpoints of flame retardancy and heat resistance, the weight average molecular weight (Mw) of the copolymer (D) is preferably 10,000 to 500,000, more preferably 20,000 to 400,000, even more preferably 30,000 to 300,000, and still more preferably 50,000 to 200,000. The weight average molecular weight (Mw) of the copolymer (D) is measured by gel permeation chromatography (GPC) in terms of polystyrene.

[0080] From the viewpoint of imparting compatibility with the polyamide (A), the acid value of the copolymer (D) is preferably 200 to 400 mg KOH / g, more preferably 250 to 350 mg KOH / g. The acid value can be measured by near-infrared spectroscopy or a neutralization number test using potassium hydroxide.

[0081] The copolymer (D) may be a commercially available product or may be synthesized by a known method. The bonding form between the structural unit derived from at least one selected from the group consisting of styrene and α-methylstyrene and the structural unit derived from at least one selected from the group consisting of maleic anhydride and a monoalkyl maleic anhydride having an alkyl group having from 1 to 3 carbon atoms is not particularly limited, and may be any of random polymerization, block polymerization, and graft polymerization.

[0082] From the viewpoint of obtaining a flame-retardant polyamide resin molded article having excellent blister resistance, the content of copolymer (D) is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 8 parts by mass, even more preferably 0.8 to 5 parts by mass, still more preferably 1.0 to 4 parts by mass, and most preferably 1.2 to 3 parts by mass, relative to 100 parts by mass of polyamide (A).

[0083] [Colorant (E)] The polyamide resin composition of this embodiment contains a colorant (E), which provides visibility and decorativeness. The colorant (E) used in this embodiment is at least one of an organic colorant and an inorganic colorant. The colorant (E) may be used alone or in combination of two or more.

[0084] Examples of organic colorants include organic dyes such as anthraquinone dyes, perinone dyes, anthrapyridone dyes, methine dyes, azine dyes, azo dyes, azomethine dyes, phthalocyanine dyes, quinoneimine dyes, quinoline dyes, nitro dyes, indigo dyes, and oxazine dyes; and organic pigments such as azo lake pigments, insoluble monoazo pigments, insoluble disazo pigments, and chelate azo pigments, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, diketopyrrolopyrrole pigments, benzimidazolone pigments, and threne pigments. Among these, from the viewpoints of heat resistance, color development, and compatibility, at least one selected from the group consisting of anthraquinone dyes, perinone dyes, anthrapyridone dyes, phthalocyanine dyes, azo pigments, and phthalocyanine pigments is preferred, and at least one selected from the group consisting of anthraquinone dyes, perinone dyes, anthrapyridone dyes, and phthalocyanine dyes is more preferred. Also, from the same viewpoints, quinoline dyes, anthraquinone dyes, perinone dyes, anthrapyridone dyes, phthalocyanine dyes, azo pigments, and phthalocyanine pigments are preferred, and at least one selected from the group consisting of quinoline dyes, anthraquinone dyes, perinone dyes, and phthalocyanine pigments is more preferred.

[0085] Examples of inorganic colorants include black inorganic pigments such as carbon black, lamp black, acetylene black, bone black, thermal black, channel black, furnace black, and titanium black; titanium oxide (TiO, Ti ２ O ３ , TiO ２ ), zinc oxide (Pb ３ O ４ ), iron oxide (Fe ２ O ３Examples of suitable pigments include metal oxides such as black inorganic pigments, antimony oxide, and zirconium oxide (zircon oxide), metal sulfides such as zinc sulfide, ultramarine (Pigment Blue 29), zinc phosphate, barium sulfate, manganese phosphate, cobalt aluminate, cobalt stannate, cobalt zincate, antimony oxide, antimony sulfide, cerium sulfide, lanthanum sulfide, chromium oxide, zinc chromate, and composite metal oxides containing a plurality of oxides such as nickel-based, bismuth-based, vanadium-based, molybdenum-based, cadmium-based, titanium-based, zinc-based, manganese-based, cobalt-based, iron-based, chromium-based, antimony-based, magnesium-based, and aluminum-based. Among these, from the viewpoint of heat resistance, at least one selected from the group consisting of black inorganic pigments, metal oxides, metal sulfides, and composite metal oxides is preferred, and at least one selected from the group consisting of carbon black, metal oxides, metal sulfides, and composite metal oxides is more preferred. From the viewpoint of providing a molded product with a color other than black, it is preferable to use at least one selected from the group consisting of metal oxides, metal sulfides, and composite metal oxides.

[0086] When the colorant (E) contains an organic colorant, the content of the organic colorant is preferably 0.0001 to 0.5 mass%, more preferably 0.001 to 0.5 mass%, and even more preferably 0.005 to 0.5 mass%, relative to 100 mass% of the polyamide resin composition of this embodiment, from the viewpoints of flame retardancy, color development, and mechanical properties.

[0087] When the colorant (E) contains an inorganic colorant, the content of the inorganic colorant is preferably 0.001 to 5.0 mass%, more preferably 0.01 to 5.0 mass%, and even more preferably 0.1 to 5.0 mass%, relative to 100 mass% of the polyamide resin composition of this embodiment, from the viewpoints of flame retardancy, color development, and mechanical properties.

[0088] The content of the colorant (E) is preferably 0.0005 to 20 parts by mass, more preferably 0.001 to 15 parts by mass, even more preferably 0.01 to 10 parts by mass, still more preferably 0.1 to 5 parts by mass, and even more preferably 0.2 to 1 part by mass, relative to 100 parts by mass of the polyamide (A). When the content of the colorant (E) is 0.0005 parts by mass or more, a color with high visibility can be developed, and when it is 20 parts by mass or less, a decrease in the mechanical properties of the molded article can be suppressed.

[0089] From the viewpoint of satisfying the specifications required for applications in automotive parts and electrical and electronic parts, the polyamide resin composition of this embodiment preferably has a ΔE represented by the following formula (3) of greater than 1. From the viewpoint of improving visibility, ΔE is more preferably greater than 3, even more preferably greater than 10, and even more preferably greater than 30. The inorganic filler (C) and colorant (E) contained in the polyamide resin composition of this embodiment are preferably selected so as to satisfy this requirement.

[0090] ... (X)

[0091] In formula (X), ΔE is the value measured by CIE 1976 (L ＊ a ＊ b ＊ ) is the color difference defined by the color system. ＊ ｃｏｌ , a ＊ ｃｏｌ , and b ＊ ｃｏｌ The polyamide resin composition of this embodiment is CIE1976 (L ＊ a ＊ b ＊ ) L defined by the color system ＊ , a ＊ , and b ＊ That is, the polyamide resin composition of this embodiment has a CIE 1976 (L ＊ a ＊ b ＊ ) L defined by the color system ＊ L ＊ ｃｏｌ and a ＊ Gaa ＊ ｃｏｌand b ＊ Ga b ＊ ｃｏｌ It is. ＊ ｎａｔ , a ＊ ｎａｔ , and b ＊ ｎａｔ is a CIE1976 (L) of a colorant-free polyamide resin composition having the same composition as the polyamide resin composition except that it does not contain the colorant (E). ＊ a ＊ b ＊ ) L defined by the color system ＊ , a ＊ , and b ＊ That is, the CIE1976 (L) of a colorant-free polyamide resin composition having the same composition as the polyamide resin composition except that it does not contain the colorant (E) is ＊ a ＊ b ＊ ) L defined by the color system ＊ L ＊ ｎａｔ and a ＊ Gaa ＊ ｎａｔ and b ＊ Ga b ＊ ｎａｔ is.

[0092] The ΔE can be determined by the following method. A polyamide resin composition of this embodiment and a colorant-free polyamide resin composition having the same composition as the polyamide resin composition of this embodiment except that it does not contain the colorant (E) are prepared, and dumbbell-shaped tensile test pieces (Type A1) of each resin composition are prepared by a method in accordance with JIS K7139:2009. An image of each test piece is obtained using a colorimeter, and the L of each test piece is determined from this image. ＊ a ＊ b ＊ More specifically, it can be determined by the method described in the examples below.

[0093] [Flame-retardant synergist (F)] The polyamide resin composition of this embodiment may further contain a flame-retardant synergist (F). By using the flame-retardant synergist (F) in combination with the brominated flame retardant (B), the resulting molded article can exhibit even more excellent flame retardancy.

[0094] Examples of the flame retardant aid (F) include antimony compounds such as antimony oxides (e.g., diantimony trioxide, diantimony tetraoxide, diantimony pentoxide), and antimonates (e.g., sodium antimonate); melamine compounds (e.g., melamine orthophosphate, melamine pyrophosphate, melamine borate, melamine polyphosphate); tin oxides (e.g., tin monoxide, tin dioxide); iron oxides (e.g., ferric oxide, γ-iron oxide); metal oxides (e.g., manganese oxide, molybdenum oxide, cobalt oxide, bismuth oxide, tin oxide, nickel oxide, copper oxide, tungsten oxide); metal hydroxides (e.g., aluminum hydroxide); metal powders (e.g., aluminum, iron, titanium, manganese, zinc, molybdenum, cobalt, bismuth, chromium, tin, antimony, nickel, copper, tungsten, etc.); metal carbonates (e.g., zinc carbonate, barium carbonate); metal borates (e.g., zinc borate, calcium borate); zinc stannates (e.g., zinc tin trioxide); and silicones. However, those corresponding to the inorganic filler (C) and the colorant (E) are excluded. These may be used alone or in combination of two or more.

[0095] Among the above, at least one selected from the group consisting of antimony compounds, melamine compounds, metal oxides, metal hydroxides, metal borates, and zinc stannate is preferred, and at least one selected from the group consisting of diantimony trioxide, diantimony tetroxide, diantimony pentoxide, sodium antimonate, melamine orthophosphate, melamine pyrophosphate, melamine borate, melamine polyphosphate, aluminum hydroxide, zinc borate, and zinc tin trioxide is more preferred.

[0096] The flame retardant aid (F) is preferably contained in the polyamide resin composition of this embodiment in the form of a powder. The upper limit of its average particle size is preferably 30 μm, more preferably 15 μm, even more preferably 10 μm, and particularly preferably 7 μm. On the other hand, the lower limit of the average particle size of the flame retardant aid (F) is preferably 0.01 μm. When the average particle size is 0.01 to 30 μm, the flame retardancy of the resulting molded article is improved. In this specification, the "average particle size" refers to the volume-average particle size, and can be determined from the particle size at which the cumulative volume is 50% (50% particle size D50) in the particle size distribution measured using a laser diffraction particle size distribution analyzer.

[0097] When the polyamide resin composition of this embodiment contains the flame retardant synergist (F), the content of the flame retardant synergist (F) is preferably 1 to 20 parts by mass, more preferably 2 to 18 parts by mass, even more preferably 3 to 15 parts by mass, and still more preferably 4 to 10 parts by mass, per 100 parts by mass of the polyamide (A). This makes it possible to significantly achieve the above-mentioned effects.

[0098] [Other Components] The polyamide resin composition of the present embodiment may contain other components as needed in addition to the above-described polyamide (A), brominated flame retardant (B), inorganic filler (C), aromatic vinyl copolymer (D), colorant (E), and flame retardant aid (F) used as needed.

[0099] Examples of other components include stabilizers such as copper compounds; antioxidants such as hindered phenol antioxidants, hindered amine antioxidants, phosphorus antioxidants, and thio antioxidants; ultraviolet absorbers; light stabilizers; antistatic agents; heat stabilizers; crystal nucleating agents; plasticizers; lubricants; mold release agents; glidants; dispersants; oxygen absorbers; hydrogen sulfide adsorbents; crystallization retarders; impact modifiers such as α-olefin copolymers and rubbers; and anti-drip agents such as fluororesins.

[0100] The content of the other components is not particularly limited as long as it does not impair the effects of the present invention, but is preferably 0.02 to 200 parts by mass, more preferably 0.03 to 100 parts by mass, even more preferably 0.05 to 50 parts by mass, and still more preferably 0.1 to 20 parts by mass, relative to 100 parts by mass of polyamide (A).

[0101] In the polyamide resin composition of this embodiment, the total content of polyamide (A), brominated flame retardant (B), inorganic filler (C), aromatic vinyl copolymer (D), and colorant (E) is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 85% by mass or more, and even more preferably 90% by mass or more. The polyamide resin composition of this embodiment preferably contains 25 to 70 parts by mass of the brominated flame retardant (B), 30 to 250 parts by mass of the inorganic filler (C), 0.1 to 10 parts by mass of the aromatic vinyl copolymer (D), and 0.0005 to 20 parts by mass of the colorant (E) per 100 parts by mass of the polyamide (A).

[0102] (Method for Producing Polyamide Resin Composition) The method for producing the polyamide resin composition is not particularly limited, and known methods can be used. For example, a method of melt-kneading polyamide (A), brominated flame retardant (B), inorganic filler (C), aromatic vinyl copolymer (D), colorant (E), and optionally, flame retardant aid (F), as well as the other components described above, can be used. The melt-kneading method is not particularly limited, and any method that can uniformly mix the components can be preferably used. For example, a single-screw extruder, a twin-screw extruder, a kneader, a Banbury mixer, or the like is preferably used. The melt-kneading conditions are not particularly limited as long as the particle size of the brominated flame retardant (B) particles can be sufficiently reduced. For example, a method of melt-kneading for about 1 to 30 minutes at a temperature range about 10 to 50°C higher than the melting point of polyamide (A) can be used.

[0103] <Molded Article> A molded article can be obtained by subjecting the polyamide resin composition, for example, in the form of pellets, to various molding methods. The molding method for the molded article may be appropriately selected depending on the application, and methods such as injection molding, extrusion molding, blow molding, compression molding, press molding, and calendar molding can be used. Injection molding is preferred when manufacturing parts such as connectors. The molded article of the polyamide resin composition of this embodiment is preferably an injection molded article. In particular, the polyamide resin composition of this embodiment gives a flame-retardant polyamide resin molded article that has excellent blister resistance even when exposed to high temperatures during the reflow process, and therefore the molded article is suitable as an injection molded article used in applications that include a surface mounting process (hereinafter also referred to as an "SMT process").

[0104] A commercially available injection molding machine can be used for injection molding. Injection molding can be performed, for example, at an injection speed of 60 mm / s, a holding pressure of 60 MPa, a holding time of 1.0 second, a cooling time of 4.0 seconds, and a cycle time of 11.0 seconds. Depending on the composition, the injection time is approximately 0.15 seconds, and the filling pressure is approximately 60 MPa. The cylinder temperature can be set, for example, from the cylinder nozzle to 320°C, 320°C, 320°C, 320°C, and 300°C. Preferably, injection molding in this manner can produce a molded product in which the aforementioned Rs1 satisfies a specific range. Similarly, the aforementioned Rs2 can be obtained in a specific range. Similarly, the aforementioned As can be obtained in a specific range. Similarly, the aforementioned EqD×π can be obtained in a specific range.

[0105] <Applications> The molded article of the polyamide resin composition of this embodiment can be used as an electric part, an electronic part, an automobile part, an industrial part, a faucet part, a fiber, a film, a sheet, a household product, a leisure product, or any other molded article of any shape and application.

[0106] Examples of electrical and electronic components include connectors such as FPC connectors, BtoB connectors, card connectors, SMT connectors (coaxial connectors, etc.), and memory card connectors; SMT relays; SMT bobbins; sockets such as memory sockets and CPU sockets; switches such as command switches and SMT switches; optical components such as optical fiber components and optical sensors; LED application components such as LED reflectors; and electronic substrates such as solar cell substrates, LED mounting substrates, flexible printed wiring boards, and resin molded circuit boards.

[0107] Automotive parts include, for example, cooling parts such as thermostat housings, coolant control valve housings, thermal management module housings, radiator tanks, radiator hoses, water outlets, water inlets, water pump housings, and rear joints; intake and exhaust system parts such as intercooler tanks, intercooler cases, turbo duct pipes, EGR cooler cases, resonators, throttle bodies, intake manifolds, and tail pipes; fuel system parts such as fuel delivery pipes, gasoline tanks, quick connectors, canisters, pump modules, fuel piping, oil strainers, lock nuts, and seals; structural parts such as mount brackets, torque rods, and cylinder head covers; bearing retainers, gear tensioners, and head seals. drivetrain parts such as headlamp actuator gears, throttle valve gears, sliding door rollers, and peripheral clutch parts; brake system parts such as air brake tubes; automotive electrical parts such as wire harness connectors in the engine compartment, motor parts, sensors, ABS bobbins, combination switches, and on-board switches; and interior and exterior parts such as sliding door dampers, door mirror stays, door mirror brackets, inner mirror stays, roof rails, engine mount brackets, air cleaner inlet pipes, door checkers, plastic chains, emblems, clips, breaker covers, cup holders, airbags, fenders, spoilers, radiator supports, radiator grilles, louvers, air scoops, hood bulges, back doors, and fuel sender modules.

[0108] Examples of industrial parts include gas pipes, oil field drilling pipes, hoses, anti-termite cables (communication cables, pass cables, etc.), paint parts of powder coated products (inner coatings of water pipes, etc.), undersea oil field pipes, pressure-resistant hoses, hydraulic tubes, paint tubes, fuel pump housings and impellers, separators, supercharger ducts, butterfly valves, conveyor roller bearings, railway sleeper spring supports, outboard motor engine covers, generator engine covers, wind turbine blades, irrigation valves, large switches, and monofilaments (extruded threads) for fishing nets, etc.

[0109] Examples of faucet parts include housings for parts that transport tap water, housings for parts that store tap water, filter casing housings, faucet housings, pipe housings, housings for bathroom faucets (hot and cold water switching valves, water volume switching valves, etc.), housings for sanitary parts, housings for kitchen faucets, housings for water heaters, valve parts (shut-off balls, slides, cylinders) and valve part housings, housings for toilet stop valves, housings inside shower heads, valve housings for water heaters, fittings for residential piping (underfloor piping, etc.), fittings for bathroom faucets, fittings for water piping, pipe joints, and housings for water meters. Housings, water meter parts (bearings, propellers, pins) and water meters, gas meter housings, distributor housings, valve / pump housings for household appliances, steam-resistant parts for steam irons, inner containers for electric kettles, dishwasher parts (washing tubs, washing nozzles, baskets), pump housings, pump parts (e.g. turbine wheels, impellers), housings for water supply systems (hot water tanks, etc.), housings for heating systems, housings for cooling systems, water volume control valves, pressure reducing valves, relief valves, solenoid valves, three-way valves, thermovalves, water temperature sensors, water volume sensors, bathtub adapters, etc.

[0110] Examples of household products include valve / pump housings for tea and coffee makers; valve / pump housings for cooking appliances such as rice cookers and steamers; steam-resistant parts for cooking appliances such as rice cookers and steamers (such as rice cooker lids); sliding parts for cooking appliances such as rice cookers and steamers (such as gears); sliding parts for commercial cooking appliances (such as gears for gear pumps); steam-resistant parts for commercial cooking appliances (such as pipes for commercial rice cookers).

[0111] Examples of leisure goods include inner soles for sports shoes, racket frames and grommets, golf club heads and sleeves, fishing reels and rods, boat propellers, bicycle suspensions, gears, saddles, and bottle cages.

[0112] The molded article of the polyamide resin composition of this embodiment can be produced by injection molding, and therefore can be suitably used for electrical and electronic components that require the production of a large number of parts in a short period of time. Specifically, the molded article can be suitably used for electrical and electronic components that involve an SMT process, more specifically, for surface-mounted components such as SMT-compatible connectors, SMT relays, SMT bobbins, sockets, command switches, SMT switches, camera modules, power supply components, sensors, capacitor base plates, hard disk components, resistors, fuse holders, coil bobbins, and IC housings.

[0113] A particularly suitable example of a molded article made from the polyamide resin composition of this embodiment is a part of an SMT-compatible automotive connector. SMT-compatible automotive connectors generally include a housing and terminals made from a resin composition using a resin with a melting point of 260°C or higher. SMT-compatible automotive connectors may also include a seal ring, gasket, shell, and the like. Automotive connectors typically have larger external dimensions than connectors for consumer electronics. Furthermore, automotive connectors are exposed to higher temperatures during the SMT process, and blistering is likely to occur during the preheating step of the SMT process due to the difficulty in releasing moisture from the molded article. Furthermore, high flame retardancy is required. Furthermore, blistering is not acceptable due to the strict quality requirements for automotive applications. Therefore, molded articles are required to have excellent blister resistance even when exposed to high temperatures during the SMT process. Molded articles made from the polyamide resin composition of this embodiment can meet these requirements and are therefore suitable for use as part of automotive connectors.

[0114] The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited to these.

[0115] The evaluations in the examples and comparative examples were carried out according to the methods shown below.

[0116] <1. Color Value (ΔE)> The color value of the polyamide resin composition obtained in each example and comparative example, L ＊ a ＊ b ＊ For the measurement, dumbbell-shaped tensile test pieces (type A1) were prepared from the polyamide resin compositions obtained in each Example and Comparative Example by a method in accordance with JIS K7139:2009. col In addition, polyamide resin compositions having the same composition as the polyamide resin compositions obtained in the examples and comparative examples except that they did not contain the colorant (E) were prepared, and dumbbell-shaped tensile test pieces (Type A1) (Test Piece A) were prepared in the same manner. nat The measurement was carried out by acquiring an image using the following measurement device, light source, sensor and measurement geometry, transmitting the image to the following equipment, and then using the following software on the equipment to measure the L ＊ a＊ b ＊ Measurement device: RAL COLORCATCH NANO colorimeter manufactured by RAL gGmbH Light source: CIE standard light source D65 Sensor: CCD camera (224 x 224 pixels) Measurement geometry: 45° / 0° Software: RAL iCOLOURS (version 3.7.2) Equipment used: iPhone (registered trademark) 8 (iOS 13.3) manufactured by Apple ＊ a ＊ b ＊ From this, ΔE represented by the following formula (X) was calculated.

[0117] ... (X)

[0118] In addition, in formula (X), L ＊ ｃｏｌ , a ＊ ｃｏｌ , and b ＊ ｃｏｌ indicates the polyamide resin composition obtained in each example (test piece A col ) CIE1976 (L ＊ a ＊ b ＊ ) L defined by the color system ＊ , a ＊ , and b ＊ and L ＊ ｎａｔ , a ＊ ｎａｔ , and b ＊ ｎａｔ A colorant-free polyamide resin composition (test piece A) has the same composition as the above polyamide resin composition except that it does not contain the colorant (E). nat ) CIE1976 (L ＊ a ＊ b ＊ ) L defined by the color system ＊ , a ＊ , and b ＊ Table 1 shows ΔE.

[0119] <2. Evaluation of Flame Retardancy> Flame retardancy was evaluated in accordance with the provisions of the UL-94 standard. Using an injection molding machine (clamping force: 80 tons, screw diameter: φ26 mm) manufactured by Nissei Plastic Industrial Co., Ltd., the polyamide resin compositions obtained in the Examples and Comparative Examples were molded at a cylinder temperature (320°C) 14°C higher than the melting point of the polyamide (A) component, and a mold temperature of 140°C, to obtain multiple test pieces B1 having a thickness of 0.75 mm, a width of 13 mm, and a length of 125 mm. Similarly, multiple test pieces B2 having a thickness of 3.0 mm, a width of 13 mm, and a length of 125 mm were obtained.

[0120] Next, for the obtained test pieces B1 and B2, the upper end was clamped to fix each test piece vertically, and a predetermined blue flame 20±1 mm high was applied to the lower end for 10 seconds and then released, and the burning time (first time) of each test piece was measured. Immediately after the fire was extinguished, the flame was again applied to the lower end and released, and the burning time (second time) of each test piece was measured. The same measurement was repeated for five pieces, obtaining a total of 10 data points: five data points for the first burning time and five data points for the second burning time. The total of the 10 data points was designated T, and the maximum value of the 10 data points was designated M, and the test pieces were evaluated according to the following evaluation criteria. The presence or absence of dripping during flame exposure was also visually confirmed.

[0121] [Evaluation criteria] V-0: T was 50 seconds or less and M was 10 seconds or less, the flame did not spread to the clamp, and even when the flaming molten material fell, it did not ignite the cotton 12 inches below. V-1: T was 250 seconds or less and M was 30 seconds or less, the flame did not spread to the clamp, and even when the flaming molten material fell, it did not ignite the cotton 12 inches below. V-2: T was 250 seconds or less and M was 30 seconds or less, the flame did not spread to the clamp, and even when the flaming molten material fell, it ignited the cotton 12 inches below. X: If none of the evaluation criteria of UL94 were met.

[0122] 3. Calculation of Parameters Rs1, Rs2, As, EqD, and (bs / as)> 3-1. Preparation of Test Piece C Using an injection molding machine (clamping force: 18 tons, screw diameter: φ18 mm) manufactured by Sumitomo Heavy Industries, Ltd., the polyamide resin compositions obtained in the Examples and Comparative Examples were injection-molded in a mold having a film gate with a width of 10 mm and a height of 0.9 mm under conditions of a cylinder temperature (320°C) 14°C higher than the melting point of the polyamide component (A) and a mold temperature of 140°C, thereby preparing a plurality of sheet-like test pieces C made of the polyamide resin composition, each measuring 30 mm in length, 10 mm in width, and 1.0 mm in thickness. The injection molding was performed at an injection speed of 60 mm / s, a holding pressure of 60 MPa, a holding time of 1.0 second, a cooling time of 4.0 seconds, and a cycle time of 11.0 seconds. Although it depends on the composition, the injection time was about 0.15 seconds and the filling pressure was about 60 MPa. The cylinder temperatures were set to 320°C, 320°C, 320°C, 320°C, and 300°C, in that order from the cylinder nozzle.

[0123] 3-2. Cross-Section Observation of Test Specimen C The obtained test specimen C was cut with a razor, with the upper surface as the principal surface in the direction of resin flow during injection molding, to expose a thickness-wise cross section (coronal plane) as the cut surface (see Figure 1). The cut position of test specimen C was 0.1 cm (=1 mm) in the length direction (L direction) of test specimen C from the film gate (one end of test specimen C in the L direction), which is the starting point of the resin flow direction during injection molding, and parallel to the width direction (W direction) of test specimen C (dashed line in Figure 2). Next, test specimen C with the exposed thickness-wise cross section was temporarily embedded in epoxy resin. The cut surface of test specimen C was then polished using a mechanical polisher "SP-150" manufactured by Subtec Co., Ltd., to achieve a polished surface. In this way, test specimen C with a polished surface was prepared. Next, a backscattered electron image (SEM image) of the polished surface of test piece C was obtained at 23°C under high vacuum at a magnification of 5000x using a field emission scanning electron microscope "Regulus 8220" (detector: LA backscattered electron mode) manufactured by Hitachi High-Tech Corporation. At this time, the brightness and contrast of the image were adjusted using the brightness / contrast automatic adjustment button.

[0124] 3-3. Image Analysis of Test Piece C Next, from the acquired SEM image, an SEM image of a region in the thickness direction cross section of test piece C, which was 250 μm ± 8.8 μm deep from the main surface of test piece C and had a width of 25 μm perpendicular to the thickness direction (T direction), was adopted as the analysis region. The width of such an analysis region was adopted as a range of ± 12.5 μm from the center position (midpoint) in the width direction (W direction) of test piece C (see Figure 1). The analysis region is shown as the part surrounded by a dashed line identified as "region" in the partially enlarged view of the thickness direction cross section of test piece C in Figure 1. Figure 3 shows an SEM image of the analysis region of test piece C in Example 3. However, in Comparative Example 4, the particle diameter of the brominated flame retardant was too large to fit within the above observation field, so it was determined that measurement was impossible. The SEM image of the analysis area was imported into Thermo Fisher Scientific's image analysis software "Avizo 3D" (ver. 2022.2) (hereinafter also referred to simply as "analysis software") and image analysis was performed. The image was imported so that the top end of the SEM image parallel to the main surface of the test piece C was the top end of the image after import. The SEM image of the analysis area was converted to 0.02 μm / voxel data and operated according to the following procedure.

[0125] (1) Noise Removal The GPU Standard Mode of the "Non-Local Means Filter" processing of the analysis software was used to remove noise from the image.

[0126] (2) Classification In the images obtained in (1) above, the polyamide (A), brominated flame retardant (B), and flame retardant synergist (F) particles were binarized based on their respective brightness values, and markers were set. Except for Comparative Example 4, the images of the Examples and Comparative Examples did not contain inorganic filler (C). The intensity ranges were 0 to 100 for polyamide (A), 93 to 165 for brominated flame retardant (B), and 157 to 255 for flame retardant synergist (F), and the analysis was performed with each value set to avoid overlap. Next, the "Marker-Based Watershed" function of the analysis software was used. As a result, the polyamide (A), brominated flame retardant (B), and flame retardant synergist (F) particles were clearly distinguishable on the image.

[0127] (3) Fractionation In the image obtained in (2) above, the "Separate Objects" function of the analysis software was used for the particles of brominated flame retardant (B). This set a boundary line between adjacent particles of brominated flame retardant (B), allowing them to be treated as individually identifiable particles. Next, noise was removed. This removed dot holes of 10 pixels or less. Note that dot holes are an example of noise caused by reflection and scattering during photography to obtain an SEM image.

[0128] (4) Analysis of Objects Next, the images obtained in (3) above were subjected to the following image analysis using the functions of the analysis software, with the particles of the brominated flame retardant (B) as the object.

[0129] (4-1) AsAs(μm ２ In order to obtain the cross-sectional area (μm ) of each particle of the brominated flame retardant (B), the "Label Analysis" function of the analysis software was used as follows. The "Area" function of the "Label Analysis" function was used. ２ The numerical average value of these values ​​for the number of objects was calculated as As (μm ２ ) was adopted.

[0130] (4-2) Calculation of Rs1 in Equation (1)

[0131] (4-2-1) bs / as in Equation (1) The "FeretShape" function of the "Label Analysis" function of the analysis software was used. The angle was set in 18° increments, with the horizontal direction of the image being 0°. This resulted in the acquisition of a FeretShape value for each particle of the brominated flame retardant (B). The number average value of these values ​​for the number of objects was then adopted as the value of bs / as in Equation (1).

[0132] (4-2-2) Calculation of Rs1 Based on the following formula (1), Rs1 (μm ２ ) was calculated. Rs1 = (bs / as) × As (1) In this calculation, As (μm ２) and the bs / as value obtained in (4-2-1) above were used.

[0133] (4-3) Calculation of EqD and EqD × π To determine EqD (μm), the "Label Analysis" function of the analysis software was used as follows. The "EqDiameter" function of the "Label Analysis" function was used. This resulted in obtaining the diameter of a perfect circle having the same area as the cross-sectional area of ​​each particle of the brominated flame retardant (B). The number average value of these values ​​for the number of objects was then adopted as the value of EqD (μm). Next, EqD × π was calculated.

[0134] (4-4) Calculation of Rs2 from Equation (2) Rs2 (μm) was calculated based on the following equation (2): Rs2 = (bs / as) × EqD × π (2) For this calculation, the EqD (μm) obtained in (4-3) above and the value of bs / as obtained in (4-2-1) above were used.

[0135] <4. Evaluation of Blister Resistance> The test pieces C obtained in 3-1 above were left to stand for 168 hours under conditions of a temperature of 85°C and a relative humidity of 85%. Thereafter, a reflow test was performed on the test pieces C using a reflow system (TNX25-30EM, manufactured by Tamura Corporation). In the reflow test, the temperature was raised from 25°C to 150°C over 60 seconds, then raised to 180°C over 90 seconds, and further raised to the peak temperature over 60 seconds, and held at the peak temperature for 20 seconds. The peak temperature was 270°C.

[0136] After the reflow test, the appearance of each test piece was visually observed. If even a small blister occurred in one location on the surface of the test piece C, it was determined that a blister had occurred on the test piece C.

[0137] The blister incidence rate was calculated from the observation results of 100 test pieces C. Specifically, the blister incidence rate was calculated as the ratio (percentage) of the number of test pieces on which a blister occurred at least at one location among the 100 test pieces.

[0138] Blister resistance was evaluated using the following five-level index. Evaluation results of "A" and "B" indicate acceptable levels for practical use. A: Blister occurrence rate is 0% or more and less than 10% B: Blister occurrence rate is 10% or more and less than 25% C: Blister occurrence rate is 25% or more and less than 50% D: Blister occurrence rate is 50% or more and less than 75% E: Blister occurrence rate is 75% or more and less than 100%

[0139] <5. Evaluation of Bar Flow Length> Using an injection molding machine (clamping force: 80 tons, screw diameter: φ26 mm) manufactured by Nissei Plastic Industrial Co., Ltd., the polyamide resin compositions obtained in the Examples and Comparative Examples were molded using a mold having a width of 40 mm and a thickness of 0.5 mm at a cylinder temperature of 14°C higher than the melting point of the polyamide of component (A) (320°C). The polyamide resin compositions were molded under conditions of 1000 kgf for 5 shots, followed by 750 kgf for 10 shots, and then 750 kgf for 5 shots, and the flow lengths (mm) of the resulting polyamide molded products were measured, and the average value was taken as the bar flow length.

[0140] <6. Evaluation of Mechanical Properties> Test specimens were prepared as follows, and mechanical properties such as tensile properties and bending properties were evaluated using the test specimens.

[0141] 6-1. Preparation of Test Specimens D and E Using an injection molding machine (clamping force: 100 tons, screw diameter: φ32 mm) manufactured by Sumitomo Heavy Industries, Ltd., the polyamide resin compositions obtained in the Examples and Comparative Examples were molded using a T-runner mold at a cylinder temperature (320°C) 14°C higher than the melting point of the polyamide (A) component, and a mold temperature of 140°C to prepare multipurpose test specimens Type A1 (dumbbell-shaped test specimens as described in JIS K7139:2009: thickness 4 mm, total length 170 mm, parallel portion length 80 mm, central parallel portion width 10 mm) (hereinafter also referred to as "Test Specimen D"). A test specimen (hereinafter also referred to as "Test Specimen E") having the same shape as Test Specimen D but with a weld in the center of the parallel portion perpendicular to the longitudinal direction of the parallel portion was also molded.

[0142] 6-2. Tensile Properties: Tensile Breaking Strength and Tensile Breaking Strain Using the test piece D prepared in 6-1 above, the tensile breaking strength (MPa) and tensile breaking strain (%) were measured using a universal testing machine (manufactured by Instron) under conditions of a test speed of 1 mm / min and a gripping distance of 115 mm in accordance with ISO 527-1 (2012, 2nd edition).

[0143] 6-3. Tensile Properties: Weld Tensile Breaking Strength Using the test piece E prepared in 6-1 above, the weld tensile breaking strength (MPa) was measured using a universal testing machine (manufactured by Instron) in accordance with ISO 527-1 (2012, 2nd edition) at a test speed of 1 mm / min and a gripping distance of 115 mm.

[0144] 6-4. Flexural Properties: Flexural Strength and Flexural Modulus Using the test piece D prepared in 6-1 above, the flexural strength (MPa) and flexural modulus (GPa) were measured in accordance with ISO 178 (2012, 2nd edition) at a test speed of 2 mm / min and a support distance of 64 mm using a universal testing machine (manufactured by Instron).

[0145] Example 1 100 parts by mass of polyamide (A2) as the component (A), 49 parts by mass of pellets of brominated flame retardant (B-1) as the component (B), 1.2 parts by mass of aromatic vinyl copolymer (D-1) as the component (D), 0.5 parts by mass of colorant (E-1) which is carbon black as the component (E), 7.1 parts by mass of flame retardant aid (F-1) as the component (F), and 0.5 parts by mass of antioxidant, 1.2 parts by mass of anti-drip agent, and 0.7 parts by mass of mold release agent as other components were extruded in a twin-screw extruder ("MEGA" manufactured by STEER Engineering). The polyamide resin composition was melt-kneaded at 320°C by feeding it from the most upstream hopper of a "32L" (screw φ31.6 mm, L / D=52, rotation speed 150 rpm, discharge rate 10 kg / h) and 78 parts by mass of glass fiber (C1-2) as component (C) from a side feeder. The melt-kneaded polyamide resin composition was extruded into a strand, cooled, and cut to obtain pellets of the polyamide resin composition. Using the obtained pellets, test pieces of predetermined shapes were prepared according to the methods described above, and various physical properties were evaluated. The results are shown in Table 1.

[0146] Examples 2 to 9 and Comparative Examples 1 to 9 Pellets of the polyamide resin composition of each Example and Comparative Example were obtained by melt kneading in the same manner as in Example 1, except that the types and amounts of each component were changed to those shown in Tables 1 and 2. Furthermore, the obtained pellets were injection molded to prepare test pieces of predetermined shapes according to the methods described above, and various physical properties were evaluated. The results are shown in Tables 1 and 2.

[0147] The components shown in Tables 1 and 2 are as follows: [Polyamide (A)] Polyamide (A-1): A polyamide in which the dicarboxylic acid units are terephthalic acid units and the diamine units are 1,9-nonanediamine units and 2-methyl-1,8-octanediamine units (molar ratio 85 / 15), melting point: 306°C, glass transition temperature: 125°C, intrinsic viscosity [η]: 0.80 dl / g Polyamide (A-2): A polyamide in which the dicarboxylic acid units are terephthalic acid units and the diamine units are 1,9-nonanediamine units and 2-methyl-1,8-octanediamine units (molar ratio 85 / 15), melting point: 306°C, glass transition temperature: 125°C, intrinsic viscosity [η]: 0.93 dl / g Polyamide (A-3): A polyamide in which the dicarboxylic acid units are terephthalic acid units and the diamine units are 1,9-nonanediamine units and 2-methyl-1,8-octanediamine units (molar ratio 85 / 15), melting point: 306°C, glass transition temperature: 125°C, intrinsic viscosity [η]: 1.0 dl / g

[0148] [Brominated Flame Retardants (B)] Flame retardant (B-1): manufactured by LANXESS, trade name "Firemaster CP-44HF" (glycidyl methacrylate modified polybrominated styrene) Flame retardant (B-2): manufactured by Albemarle, trade name "SAYTEX HP-7010" (brominated polystyrene) Flame retardant (B-3): manufactured by LANXESS, trade name "PDBS-80" (brominated polystyrene)

[0149] [Inorganic filler (C)] Glass fiber (C1-1): manufactured by Central Glass Fiber Co., Ltd., trade name "ECS03-615" (cross-sectional shape: round, average fiber diameter: 9 μm, average cut fiber length: 3 mm, amount of sizing agent (surface treatment agent) attached: 0.2% by mass relative to the total mass of glass fiber (C1) Glass fiber (C1-2): manufactured by Nippon Electric Glass Co., Ltd., trade name "T-262H" (cross-sectional shape: round, average fiber diameter: 10.5 μm, average fiber length: 3 mm, amount of sizing agent (surface treatment agent) attached: 0.4% by mass relative to the total mass of glass fiber (C1)

[0150] [Aromatic vinyl copolymers (D)] Aromatic vinyl copolymer (D-1): manufactured by Polyscope, trade name "XIBOND 160" (styrene-maleic anhydride copolymer, acid value: 250 mg KOH / g, glass transition temperature: 150°C, weight average molecular weight (Mw): 115,000) Aromatic vinyl copolymer (D-2): manufactured by Polyscope, trade name "XIBOND 250" (styrene-maleic anhydride copolymer, acid value: 280 mg KOH / g, glass transition temperature: 130°C, weight average molecular weight (Mw): 10,000)

[0151] [Colorants (E)] Colorant (E-1): Carbon black manufactured by Mitsubishi Chemical Corporation, product name "#980B" Colorant (E-2): "Zinc sulfide" (white inorganic colorant, CAS number 1314-98-3) Colorant (E-3): "Iron-manganese composite oxide" (red inorganic colorant, CAS number 12062-81-6) Colorant (E-4): "Solvent Red 52" (red organic colorant, quinoline dye, CAS number 81-39-0) Colorant (E-5): "Pigment Blue 15" (blue organic colorant, phthalocyanine pigment, CAS number 147-14-8) Colorant (E-6): "Solvent Orange 63 (orange organic colorant, anthraquinone dye, CAS number 16924-75-0) Colorant (E-7): Solvent Red 179 (red organic colorant, perinone pigment, CAS number 6829-22-7)

[0152] [Flame retardant synergist (F)] Flame retardant synergist (F-1): Nippon Light Metal Co., Ltd., trade name "Flamtard S" (zinc stannate)

[0153] [Other ingredients] Antioxidant: Sumitomo Chemical Co., Ltd., trade name "Sumilizer GA-80" (3,9-bis{1,1-dimethyl-2-[β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl}-2,4,8,10-tetraoxaspiro[5.5]undecane) Anti-drip agent: Mitsui-DuPont Fluorochemicals Co., Ltd., trade name "640-J" (polytetrafluoroethylene powder) Mold release agent: Mitsui Chemicals, Inc., trade name "Hiwax 200P" (polyolefin wax)

[0154]

[0155]

[0156] From Table 1, it was found that all of the polyamide resin compositions obtained in Examples 1 to 9 were capable of giving flame-retardant polyamide resin molded articles having excellent blister resistance even when exposed to high temperatures during the reflow process.

[0157] In Table 2, the polyamide resin compositions obtained in Comparative Examples 1 to 9 were unable to give flame-retardant polyamide resin molded articles with excellent blister resistance even when exposed to high temperatures during the reflow process. The reason why Comparative Examples 1 to 9 did not have excellent blister resistance is that Rs1 represented by formula (1) was 0.2 μm ２ Therefore, in order to provide a flame-retardant polyamide resin molded article that is excellent in blister resistance even when exposed to high temperatures during the reflow process, a test piece is prepared by injection molding from a polyamide composition prepared by melt kneading, and Rs1 represented by formula (1) is 0.2 μm or more. ２ It has been found that it is sufficient to confirm that Rs2 expressed by the formula (2) is less than 1.7 μm.

[0158] In addition, in Table 2, the polyamide resin compositions obtained in Comparative Examples 1 to 9 were unable to give flame-retardant polyamide resin molded articles with excellent blister resistance even when exposed to high temperatures during the reflow process. The reason why the blister resistance was not excellent in Comparative Examples 1 to 9 was that As was 0.1 μm ２ Therefore, in order to provide a flame-retardant polyamide resin molded article that is excellent in blister resistance even when exposed to high temperatures during the reflow process, a test piece is prepared by injection molding from a polyamide composition prepared by melt kneading, and As is 0.1 μm or more. ２ It was found that it was sufficient to confirm that EqD×π was less than 1.0 μm.

[0159] Molded articles of the polyamide resin composition of the present invention are useful for various molded articles that require high reliability of electrical connections, particularly automobile parts and electric / electronic parts.

Claims

1. A polyamide resin composition comprising a polyamide (A) having a melting point of 280°C or higher, a brominated flame retardant (B), an inorganic filler (C), an aromatic vinyl copolymer (D) and a colorant (E), wherein the polyamide (A) contains diamine units, and 50 to 100 mol% of the diamine units are aliphatic diamine units having 4 to 18 carbon atoms, and the colorant (E) is at least one of an organic colorant and an inorganic colorant, and when particles of the brominated flame retardant (B) are observed in a region at a depth of 250 μm ± 8.8 μm from the main surface of a test piece having a length of 30 mm, a width of 10 mm, and a thickness of 1.0 mm made of the polyamide resin composition, and the width perpendicular to the thickness direction is 25 μm, the number average value As (μm ２ ) is 0.1 μm ２ A smaller polyamide resin composition.

2. The polyamide resin composition according to claim 1, wherein, when particles of the brominated flame retardant (B) in the region are observed, the product EqD×π (μm) of the number average value EqD of the diameters of true circles having the same area as the cross-sectional area of ​​the particles of the brominated flame retardant (B) and pi is smaller than 1.0 μm.

3. A polyamide resin composition comprising a polyamide (A) having a melting point of 280°C or higher, a brominated flame retardant (B), an inorganic filler (C), an aromatic vinyl copolymer (D) and a colorant (E), wherein the polyamide (A) contains diamine units, and 50 to 100 mol% of the diamine units are aliphatic diamine units having 4 to 18 carbon atoms, and the colorant (E) is at least one of an organic colorant and an inorganic colorant, and when particles of the brominated flame retardant (B) are observed in a region at a depth of 250 μm ± 8.8 μm from the main surface of a test piece having a length of 30 mm, a width of 10 mm, and a thickness of 1.0 mm, made of the polyamide resin composition, and a width of 25 μm perpendicular to the thickness direction, Rs1 (μm ２ ) is 0.2 μm ２ A polyamide resin composition having a smaller particle size than the above. Rs1=(bs / as)×As (1) [In the formula (1), bs / as is a number average value of the ratio of the perpendicular Feret diameter to the minimum Feret diameter among the Feret diameters of the particles of the brominated flame retardant (B) observed in the above region, and As is a number average value of the cross-sectional area of ​​the particles of the brominated flame retardant (B) observed in the above region (μm ２ ).

4. The polyamide resin composition according to claim 3, wherein Rs2 (μm) represented by the following formula (2) is smaller than 1.7 μm when the particles of the brominated flame retardant (B) in the region are observed: Rs2=(bs / as)×EqD×π (2) [In formula (2), bs / as is the number average value of the ratio of the perpendicular Feret diameter to the smallest Feret diameter among the Feret diameters of the particles of the brominated flame retardant (B) observed in the region, and EqD is the number average value (μm) of the diameter of a perfect circle having the same area as the cross-sectional area of ​​the particles of the brominated flame retardant (B) observed in the region.] 5. The polyamide resin composition according to any one of claims 1 to 4, wherein ΔE represented by the following formula (X) is greater than 1: ...(X) [In formula (X), ΔE is CIE1976(L ＊ a ＊ b ＊ ) color difference defined by the color system, L ＊ ｃｏｌ , a ＊ ｃｏｌ , and b ＊ ｃｏｌ The polyamide resin composition is CIE1976 (L ＊ a ＊ b ＊ ) L defined by the color system ＊ , a ＊ , and b ＊ And L ＊ ｎａｔ , a ＊ ｎａｔ , and b ＊ ｎａｔ The CIE1976 (L) of a colorant-free polyamide resin composition having the same composition as the polyamide resin composition except that it does not contain a colorant (E) is shown. ＊ a ＊ b ＊ ) L defined by the color system ＊ , a ＊ , and b ＊ It is.] 6. The polyamide resin composition according to any one of claims 1 to 5, wherein the organic colorant is at least one selected from the group consisting of anthraquinone dyes, perinone dyes, anthrapyridone dyes, and phthalocyanine dyes.

7. The polyamide resin composition according to any one of claims 1 to 6, wherein the inorganic colorant is at least one selected from the group consisting of carbon black, metal oxides, metal sulfides and composite metal oxides.

8. The polyamide resin composition according to any one of claims 1 to 7, wherein the inorganic colorant is at least one selected from the group consisting of metal oxides, metal sulfides and composite metal oxides.

9. The polyamide resin composition according to any one of claims 1 to 8, wherein the colorant (E) contains the organic colorant, and the content of the organic colorant is 0.0001 to 0.5 mass% relative to 100 mass% of the polyamide resin composition.

10. The polyamide resin composition according to any one of claims 1 to 9, wherein the colorant (E) contains the inorganic colorant, and the content of the inorganic colorant is 0.001 to 5.0 mass% relative to 100 mass% of the polyamide resin composition.

11. The polyamide resin composition according to any one of claims 1 to 10, wherein the brominated flame retardant (B) is at least one member selected from the group consisting of brominated polystyrene and polybrominated styrene.

12. The polyamide resin composition according to any one of claims 1 to 11, wherein the polyamide (A) contains dicarboxylic acid units, and in the polyamide (A), 50 mol % or more of the dicarboxylic acid units are terephthalic acid units, and the aliphatic diamine having 4 to 18 carbon atoms constituting the aliphatic diamine units having 4 to 18 carbon atoms is at least one selected from the group consisting of 1,4-butanediamine, 1,6-hexanediamine, 1,9-nonanediamine, 2-methyl-1,8octanediamine, and 1,10-decanediamine.

13. The polyamide resin composition according to claim 12, wherein the aliphatic diamine having 4 to 18 carbon atoms is at least one member selected from the group consisting of 1,9-nonanediamine and 2-methyl-1,8 octanediamine.

14. The polyamide resin composition according to any one of claims 1 to 13, wherein the aromatic vinyl copolymer (D) contains structural units derived from at least one selected from the group consisting of styrene and α-methylstyrene, and structural units derived from at least one selected from the group consisting of maleic anhydride and monoalkyl maleic anhydride having an alkyl group having from 1 to 3 carbon atoms, and the glass transition temperature of the aromatic vinyl copolymer (D) is 120°C or higher.

15. The polyamide resin composition according to claim 14, wherein the content of structural units derived from at least one selected from the group consisting of maleic anhydride and monoalkyl maleic anhydride having an alkyl group having from 1 to 3 carbon atoms in the aromatic vinyl copolymer (D) is 18 to 50 mass%.

16. The polyamide resin composition according to any one of claims 1 to 15, wherein the weight average molecular weight (Mw) of the aromatic vinyl copolymer (D) is 10,000 to 500,000.

17. The polyamide resin composition according to any one of claims 1 to 16, further comprising a flame retardant auxiliary (F).

18. The polyamide resin composition according to any one of claims 1 to 17, comprising, relative to 100 parts by mass of the polyamide (A), 25 to 70 parts by mass of the brominated flame retardant (B), 30 to 250 parts by mass of the inorganic filler (C), 0.1 to 10 parts by mass of the aromatic vinyl copolymer (D), and 0.0005 to 20 parts by mass of the colorant (E).

19. A method for producing a polyamide resin composition according to any one of claims 1 to 18, comprising melt-kneading the polyamide (A), the bromine-based flame retardant (B), the inorganic filler (C), the aromatic vinyl copolymer (D), the colorant (E), and, if necessary, the flame retardant auxiliary (F).

20. A molded article made from the polyamide resin composition according to any one of claims 1 to 18.

21. The molded article according to claim 20, which is a connector.

22. The molded article according to claim 20 or 21, which is an on-vehicle connector.

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