Polyamide resin composition and molding

Abstract

To provide a polyamide resin composition which can suppress warpage of a molding immediately after molding and after reflow while enhancing reflow heat resistance of the molding, and a molding of the same.SOLUTION: A polyamide resin composition contains a polyamide resin (A) having a melting point measured by a differential scan calorimeter (DSC) of 280°C or higher, and a fibrous reinforcement material (B), wherein the fibrous reinforcement material (B) contains a reinforcement material (B-1) having an aspect ratio of a cross section of 1.5 or more, and a reinforcement material (B-2) having an aspect ratio of a cross section of less than 1.5, and a content of the reinforcement material (B-1) is 15 mass% or more and 85 mass% or less with respect to the total mass of the reinforcement material (B-1) and the reinforcement material (B-2).SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Conventionally, polyamide resin compositions have been known as molding materials. Polyamide resin compositions are widely used, for example, as materials for various parts such as automotive parts and electrical and electronic parts, and are known to be excellent in the mechanical strength of molded articles.

[0003] From the viewpoint of improving the mechanical strength and rigidity of molded articles, it is known to include fibrous reinforcing materials such as glass fibers in polyamide resin compositions.

[0004] For example, Patent Document 1 discloses a resin composition containing a polyamide resin and glass fibers containing a specific component in a specific amount. In Patent Document 1, by using glass fibers having a circular or flat cross section, the fluidity of the resin composition was increased, and a molded article excellent in heat resistance, high-temperature rigidity, mechanical strength, impact resistance, and surface appearance could be produced.

[0005] Further, Patent Document 2 discloses a polyamide resin composition containing two specific polyamides and glass fibers having a cross-sectional area within a specific range. In Patent Document 2, the molded article of the polyamide resin was said to have a high resonance frequency, good molded article appearance, high strength, and high impact resistance.

[0006] Further, Patent Document 3 discloses a polyamide resin composition containing an aliphatic or semi-aromatic semi-crystalline polyamide and a filler such as glass fibers. According to Patent Document 3, the molded article of the polyamide resin composition was said to have high mechanical strength.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0008] As described in Patent Documents 1 to 3, polyamide resin compositions containing fibrous reinforcing materials are known.

[0009] By the way, when a molded article of a polyamide resin composition containing a semi-aromatic polyamide resin is used for automotive parts and electrical and electronic parts, etc., the molded article may be subjected to reflow soldering to a substrate. At this time, due to heating (reflow treatment) in the reflow process, the moisture contained in the molded article vaporizes, and blisters (swelling) may occur in the molded article due to the vapor pressure caused by the vaporization. From the viewpoint of improving the appearance and dimensional accuracy of the molded article, it is desirable to use a polyamide resin composition in which blisters are less likely to occur due to heating (high reflow heat resistance).

[0010] In addition, the molded article of the polyamide resin composition may warp after molding and after reflow treatment. From the viewpoint of making the molded article into a desired shape, it is desirable to use a polyamide resin composition in which warping of the molded article is less likely to occur after molding and after reflow treatment.

[0011] According to the studies of the present inventors, in the polyamide resin compositions described in Patent Documents 1 to 3, it was not possible to achieve both improvement in the reflow heat resistance of the molded article and suppression of the warping.

[0012] An object of the present invention is to provide a polyamide resin composition capable of enhancing the reflow heat resistance of a molded article and suppressing the warping of the molded article after molding and after reflow treatment, and a molded article thereof.

Means for Solving the Problems

[0013] One aspect of the present invention for solving the above problems relates to the polyamide resin compositions of the following [1] to [6]. [1] A semi-aromatic polyamide resin (A) having a melting point of 280° C. or higher measured by a differential scanning calorimeter (DSC), and a fibrous reinforcing material (B), wherein the fibrous reinforcing material (B) includes a reinforcing material (B-1) having an aspect ratio of the cross-section of 1.5 or more and a reinforcing material (B-2) having an aspect ratio of the cross-section of less than 1.5, and the content of the reinforcing material (B-1) is 15% by mass or more and 85% by mass or less with respect to the total mass of the reinforcing material (B-1) and the reinforcing material (B-2). A polyamide resin composition. [2] The polyamide resin composition according to [1], wherein the content of the reinforcing material (B-1) is 50% by mass or more and 83% by mass or less with respect to the total mass of the reinforcing material (B-1) and the reinforcing material (B-2). [3] The polyamide resin composition according to [1] or [2], wherein the aspect ratio of the cross-section of the reinforcing material (B-1) is 3.0 or more. [4] The polyamide resin composition according to any one of [1] to [3], wherein the content of the fibrous reinforcing material (B) is 20% by mass or more and 40% by mass or less with respect to the total mass of the polyamide resin composition. [5] The polyamide resin composition according to any one of [1] to [4], wherein the heat of fusion (ΔH) measured by a differential scanning calorimeter (DSC) is 10 J / g or more and 100 J / g or less. [6] The polyamide resin composition according to any one of [1] to [5], wherein the number of types of polyamide resins contained in the semi-aromatic polyamide resin (A) is one type.

[0014] One aspect of the present invention for solving the above problems relates to the molded article of the following [7]. [7] A molded article obtained by molding the polyamide resin composition according to any one of [1] to [6]. [Advantages of the Invention]

[0015] According to the present invention, it is possible to provide a polyamide resin composition capable of enhancing the reflow heat resistance of a molded article and suppressing warpage of the molded article after molding and after reflow treatment, and a molded article thereof.

Brief Description of Drawings

[0016]

Figure 1

Embodiments for Carrying Out the Invention

[0017] Hereinafter, embodiments of the present invention will be described in detail. Note that the present invention is not limited to the following embodiments.

[0018] 1. Polyamide Resin Composition The polyamide resin composition according to the present embodiment includes a semi-aromatic polyamide resin (A) having a melting point of 280°C or higher measured by a differential scanning calorimeter (DSC), and a fibrous reinforcing material (B). The fibrous reinforcing material (B) includes a reinforcing material (B-1) having an aspect ratio of the cross-section of 1.5 or more and a reinforcing material (B-2) having an aspect ratio of the cross-section of less than 1.5. The content of the reinforcing material (B-1) is 15% by mass or more and 85% by mass or less based on the total mass of the reinforcing material (B-1) and the reinforcing material (B-2).

[0019] The inventors of the present invention have found that by using the above polyamide resin composition, it is possible to enhance the reflow heat resistance of a molded article and suppress warpage of the molded article after molding and after reflow treatment.

[0020] When the polyamide resin composition is molded, it is poured into a mold in a molten state. Then, as the polyamide resin composition cools and the polyamide resin solidifies, volume shrinkage occurs due to the crystallization of the polyamide resin. At this time, if there is anisotropy in the volume shrinkage rate of the polyamide resin composition, the molded body is likely to warp and deform. Further, when the molded body after molding is subjected to a reflow process, crystallization of the non-crystallized portion of the polyamide resin proceeds due to heating and cooling in the reflow process, resulting in further volume shrinkage of the polyamide resin composition. At this time, if there is anisotropy in the volume shrinkage rate of the polyamide resin composition, the warping deformation of the molded body is even more likely to occur.

[0021] When a fibrous reinforcing material is included in the polyamide resin composition, it is considered that the fibrous reinforcing material is arranged such that the longitudinal direction of the fibrous reinforcing material is parallel to the flow direction of the polyamide resin composition during the molding of the polyamide resin composition. That is, in the molded body, the fibrous reinforcing materials are likely to be arranged such that each of the fibrous reinforcing materials follows the above flow direction. Here, when the length in the direction orthogonal to the longitudinal direction of the fibrous reinforcing material is not sufficient, the reinforcing effect on the polyamide resin composition in the orthogonal direction is significantly smaller than the reinforcing effect on the polyamide resin composition in the longitudinal direction. Therefore, in the polyamide resin composition in which the fibrous reinforcing material is oriented along the flow direction as described above, the volume shrinkage rate in the flow direction is likely to be significantly smaller than the volume shrinkage rate in the direction orthogonal to the flow direction, and as a result, anisotropy in the volume shrinkage rate is likely to occur. Therefore, when a fibrous reinforcing material having an insufficient length in the direction orthogonal to the longitudinal direction is included in the polyamide resin composition, the volume shrinkage rate will differ between the flow direction of the polyamide resin composition and the direction orthogonal to the flow direction, and the warping deformation of the molded body is likely to occur.

[0022] Here, it is known that by using a fibrous reinforcing material having a substantially flat cross-section and having a sufficient length in the direction orthogonal to the flow direction instead of the generally widely used fibrous reinforcing material having a substantially circular cross-section as the fibrous reinforcing material, anisotropy in the volume shrinkage rate can be reduced and warping deformation of the molded body can be suppressed.

[0023] However, as a result of investigations by the present inventors, it has been found that when a fibrous reinforcing material having a substantially flat cross-section is used, warpage deformation of the molded body can be suppressed, but blisters are likely to occur when the molded body is subjected to a reflow process. This is presumably because when the fibrous reinforcing material having a substantially flat cross-section is oriented in the molded body, the path through which moisture contained inside the molded body moves to the outside of the molded body is blocked or lengthened, preventing movement to the outside of the molded body, and making it easier for moisture to be retained inside the molded body. When the reflow process is performed with moisture retained inside the molded body, the moisture retained inside vaporizes and blisters are likely to form on the surface of the molded body.

[0024] Therefore, as a result of further investigations by the present inventors, as the fibrous reinforcing material (B), a reinforcing material (B-1) having an aspect ratio of the cross-section of 1.5 or more and a reinforcing material (B-2) having an aspect ratio of the cross-section of less than 1.5 are used in combination such that the content of the reinforcing material (B-1) is 15% by mass or more and 85% by mass or less with respect to the total mass of the reinforcing material (B-1) and the reinforcing material (B-2), it has been found that the reflow heat resistance of the molded body can be enhanced and warpage of the molded body after molding and after the reflow process can be suppressed.

[0025] The reinforcing material (B-2) has a shorter length in the direction perpendicular to the flow direction in a state of being oriented along the flow direction than the reinforcing material (B-1). Therefore, it is considered that when a certain amount or more of the reinforcing material (B-2) is included, a path for moisture contained inside the molded body to move is likely to be formed inside the molded body. As a result, the moisture is likely to move to the outside of the molded body, and the amount of moisture contained inside the molded body decreases during the reflow process, making it less likely for blisters to occur.

[0026] 1-1. Semi-aromatic polyamide resin (A) The semi-aromatic polyamide resin (A) is a polyamide resin having a melting point of 280°C or higher as measured by a differential scanning calorimeter (DSC). The semi-aromatic polyamide resin (A) forms crystals in the molded article and can enhance the mechanical strength (such as flexural strength) of the molded article. Further, since the semi-aromatic polyamide resin (A) has a high melting point, it is possible to suppress the melting of the polyamide resin in the reflow process. The method for measuring the melting point of the semi-aromatic polyamide resin (A) will be described later.

[0027] The semi-aromatic polyamide resin (A) is, for example, a polyamide resin containing a component unit (Aa) derived from a dicarboxylic acid and a component unit (Ab) derived from a diamine. Hereinafter, the polyamide resin containing the component unit (Aa) derived from a dicarboxylic acid and the component unit (Ab) derived from a diamine will be described.

[0028] (Component unit (Aa) derived from a dicarboxylic acid) The component unit (Aa) derived from a dicarboxylic acid preferably contains a component unit derived from an aromatic dicarboxylic acid, and more preferably contains a component unit derived from terephthalic acid.

[0029] The content of the component unit derived from an aromatic dicarboxylic acid is preferably 40 mol% or more and 100 mol% or less, more preferably 50 mol% or more and 100 mol% or less, and even more preferably 60 mol% or more and 80 mol% or less, based on the total number of moles of the component unit (Aa) derived from a dicarboxylic acid.

[0030] The content of the component unit derived from terephthalic acid is preferably 40 mol% or more and 100 mol% or less, more preferably 50 mol% or more and 100 mol% or less, still more preferably 60 mol% or more and 80 mol% or less, further preferably 40 mol% or more and 65 mol% or less, and particularly preferably 55 mol% or more and 65 mol% or less, based on the total number of moles of the component units (Aa) derived from dicarboxylic acids. When the above content is 20 mol% or more, the aromatic ring concentration in the polyamide resin (A) increases, and the polyamide resin tends to carbonize. As a result, the flame retardancy of the molded body tends to increase.

[0031] The component unit (Aa) derived from dicarboxylic acid may contain component units derived from other dicarboxylic acids. Examples of other dicarboxylic acids include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and aromatic dicarboxylic acids other than terephthalic acid. Among these, aliphatic dicarboxylic acids are preferred.

[0032] Examples of the above aliphatic dicarboxylic acids include aliphatic dicarboxylic acids having 4 to 20 carbon atoms. The number of carbon atoms is preferably 6 to 12. Examples of such aliphatic dicarboxylic acids include adipic acid, azelaic acid, and sebacic acid. Among these, adipic acid and sebacic acid are preferred, and adipic acid is more preferred.

[0033] The content of the component unit derived from the above aliphatic dicarboxylic acid is preferably 0 mol% or more and 60 mol% or less, more preferably 30 mol% or more and 60 mol% or less, still more preferably 30 mol% or more and 45 mol% or less, and particularly preferably 35 mol% or more and 45 mol% or less, based on the total number of moles of the component units (Aa) derived from dicarboxylic acids.

[0034] Examples of the above alicyclic dicarboxylic acids include cyclohexanedicarboxylic acid and its esters.

[0035] Examples of aromatic dicarboxylic acids other than terephthalic acid include isophthalic acid, 2-methylterephthalic acid, and naphthalenedicarboxylic acid.

[0036] The content of the component unit derived from an alicyclic dicarboxylic acid or an aromatic dicarboxylic acid other than terephthalic acid is preferably 20 mol% or more and 80 mol% or less, more preferably 25 mol% or more and 75 mol% or less, based on the total number of moles of the component unit (Aa) derived from the dicarboxylic acid.

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

[0038] The aliphatic diamine preferably has 4 to 12 carbon atoms, more preferably 6 to 12 carbon atoms. Examples of the aliphatic diamine include linear alkylenediamine and branched alkylenediamine.

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

[0040] Examples of the branched-chain alkylene diamine include 2,2-dimethyldiaminopropane, 1,1-dimethyl-1,4-diaminobutane, 1-ethyl-1,4-diaminobutane, 1,2-dimethyl-1,4-diaminobutane, 1,3-dimethyl-1,4-diaminobutane, 1,4-dimethyl-1,4-diaminobutane, 2,3-dimethyl-1,4-diaminobutane, 2-methyl-1,5-diaminopentane, 2,5-dimethyl-1,6-diaminohexane, 2,4-dimethyl-1,6-diaminohexane, 3,3-dimethyl-1,6-diaminohexane, 2,2-dimethyl-1,6-diaminohexane, 2,2,4-trimethyl-1,6-diaminohexane, 2,4,4-trimethyl-1,6-diaminohexane, 2,4-diethyl-1,6-diaminohexane, 2,3-dimethyl-1,7-diaminoheptane, 2,4-dimethyl-1,7-diaminoheptane, 2,5-dimethyl-1,7-diaminoheptane, 2,2-dimethyl-1,7-diaminoheptane, 2-methyl-4-ethyl-1,7-diaminoheptane, 2-ethyl-4-methyl-1,7-diaminoheptane, 2,2,5,5-tetramethyl-1,7-diaminoheptane, 3-isopropyl-1,7-diaminoheptane, 3-isooctyl-1,7-diaminoheptane, 2-methyl-1,8-diaminooctane, 1,3-dimethyl-1,8-diaminooctane, 1,4-dimethyl-1,8-diaminooctane, 2,4-dimethyl-1,8-diaminooctane, 3,4-dimethyl-1,8-diaminooctane, 4,5-dimethyl-1,8-diaminooctane, 2,2-dimethyl-1,8-diaminooctane, 3,3-dimethyl-1,8-diaminooctane, 4,4-dimethyl-1,8-diaminooctane, 3,3,5-trimethyl-1,8-diaminooctane, 2,4-diethyl-1,8-diaminooctane, and 5-methyl-1,9-diaminononane. Among these, 2-methyl-1,8-diaminooctane is preferred.

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

[0042] Examples of the alicyclic diamine having 4 to 20 carbon atoms include 1,4-diaminocyclohexane, 1,3-diaminocyclohexane, 1,3-bis(aminomethyl)cyclohexane, 2,5-bisaminomethylnorbornane, and 2,6-bisaminomethylnorbornane. Examples of the aromatic diamine include metaxylylenediamine.

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

[0044] Each constitutional unit of the semi-aromatic polyamide resin (A) and its ratio can be calculated from the charging ratio during the preparation of the semi-aromatic polyamide resin (A) or measured by the NMR method.

[0045] 1 In the case of 1H-NMR measurement, for example, a nuclear magnetic resonance apparatus (ECX400 type manufactured by JEOL Ltd.) is used, the solvent is deuterated orthodichlorobenzene, the sample concentration is 20 mg / 0.6 mL, the measurement temperature is 120 °C, and the observed nucleus is 1 1H (400 MHz), the sequence is a single pulse, the pulse width is 5.12 μs (45° pulse), the repetition time is 7.0 s, and the number of integration times is 500 times or more. The reference chemical shift is set to 0 ppm for the hydrogen of tetramethylsilane. However, the same result can also be obtained by setting the peak derived from the residual hydrogen of deuterated orthodichlorobenzene to 7.10 ppm as the reference value of the chemical shift. The 1 peaks such as 1H derived from the functional group-containing compound can be assigned by a conventional method.

[0046] 13In the case of \(^{13}\)C-NMR measurement, for example, a nuclear magnetic resonance apparatus (ECP500 type manufactured by JEOL Ltd.) is used as the measurement device, an ortho-dichlorobenzene / heavy benzene (80 / 20 vol%) mixed solvent is used as the solvent, the measurement temperature is 120 °C, and the observed nucleus is 13 \(^{13}\)C (125 MHz), single pulse proton decoupling, 45° pulse, the repetition time is 5.5 seconds, the number of integrations is 10,000 times or more, and the chemical shift reference value is 27.50 ppm. The assignment of various signals is carried out based on conventional methods, and quantification can be carried out based on the integrated value of the signal intensity.

[0047] Specific examples of the semi-aromatic polyamide resin (A) include polyamide 6T6I, polyamide 6T66, polyamide 6TDT, and the like.

[0048] The semi-aromatic polyamide resin (A) may contain only one kind of semi-aromatic polyamide resin, or may contain two or more kinds of semi-aromatic polyamide resins, but it is preferable to contain only one kind of semi-aromatic polyamide resin. By using only one kind of semi-aromatic polyamide resin, the crystallinity of the semi-aromatic polyamide resin (A) can be increased compared to when using two or more kinds of semi-aromatic polyamide resins. This is presumably because the molecules of the resin can be arranged to more easily form crystal parts without causing compatibility between multiple kinds of semi-aromatic polyamide resins. And by further increasing the crystallinity of the semi-aromatic polyamide resin (A), the molecular chain movement at high temperatures can be suppressed, so that the deformation of the molded body during the reflow process can be suppressed. As a result, the generation of blisters due to the vaporization of moisture inside the molded body can be suppressed, and the reflow heat resistance can be further enhanced. In this specification, even if the types of component units contained in the semi-aromatic polyamide resin (A) are the same, those with different contents of the above component units are treated as two or more kinds of semi-aromatic polyamide resins.

[0049] Note that the component unit derived from the dicarboxylic acid of the semi-aromatic polyamide resin (A) may contain a component unit derived from a biomass-derived dicarboxylic acid, and the component unit derived from the diamine may contain a component unit derived from a biomass-derived diamine. Further, the semi-aromatic polyamide resin (A) may be a biomass-derived semi-aromatic polyamide resin (A) obtained by polymerizing a raw material group containing a biomass-derived raw material.

[0050] (Physical properties) From the viewpoint of further enhancing the mechanical strength of the molded article, the melting point of the semi-aromatic polyamide resin (A) is 280°C or higher, preferably 290°C or higher, and more preferably 300°C or higher. Further, from the viewpoint of suppressing the decomposition of the amide bond of the semi-aromatic polyamide resin (A), the melting point of the semi-aromatic polyamide resin (A) is preferably 320°C or lower.

[0051] The melting point of the semi-aromatic polyamide resin (A) can be adjusted to the above range by adjusting the composition of the semi-aromatic polyamide resin (A). For example, the melting point can be increased by increasing the content ratio of the component unit derived from terephthalic acid described later.

[0052] Further, the semi-aromatic polyamide resin (A) preferably has a glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) of 70°C or higher and 145°C or lower, more preferably 75°C or higher and 125°C or lower, and even more preferably 80°C or higher and 100°C or lower. When the glass transition temperature (Tg) is 70°C or higher, the temperature at which the molecular mobility becomes active in a high-temperature environment increases, so that the molecular mobility can be suppressed and blister generation can be further suppressed. As a result, the reflow heat resistance can be further enhanced. Further, when the glass transition temperature (Tg) is 145°C or lower, the fluidity of the resin composition can be easily maintained without excessively increasing the mold temperature during molding, and the moldability can be improved.

[0053] The heat of fusion (ΔH) measured by differential scanning calorimetry (DSC) of the semi-aromatic polyamide resin (A) is preferably more than 5 J / g. The heat of fusion is an index of the crystallinity of the resin, and the larger the heat of fusion, the higher the crystallinity. When the heat of fusion (ΔH) of the semi-aromatic polyamide resin (A) exceeds 5 J / g, the crystallinity increases, so that the mechanical strength (such as flexural strength) of the obtained molded article can be increased.

[0054] The melting point and the heat of fusion (ΔH) of the semi-aromatic polyamide resin (A) can be measured using a differential scanning calorimeter (DSC220C type, manufactured by Seiko Instruments Inc.).

[0055] Specifically, about 5 mg of the semi-aromatic polyamide resin (A) is sealed in a measurement aluminum pan and heated from room temperature to 350 °C at 10 °C / min. To completely melt the resin, it is held at 350 °C for 3 minutes, then cooled to 30 °C at 10 °C / min. After leaving it at 30 °C for 5 minutes, the second heating is performed from 30 °C to 350 °C at 10 °C / min. The temperature (°C) of the endothermic peak in this second heating is defined as the melting point (Tm) of the semi-aromatic polyamide resin (A), and the inflection point corresponding to the glass transition is defined as the glass transition temperature (Tg). The heat of fusion (ΔH) is determined from the area of the endothermic peak during melting in the first heating process in accordance with JIS K7122.

[0056] The intrinsic viscosity [η] of the semi-aromatic polyamide resin (A), measured in 96.5% sulfuric acid at 25°C, is preferably 0.9 dl / g or more and 1.2 dl / g or less, more preferably 1.0 dl / g or more and 1.2 dl / g or less, and particularly preferably 1.0 dl / g or more and 1.1 dl / g or less. When the intrinsic viscosity [η] of the semi-aromatic polyamide resin (A) is 0.9 dl / g or more, it is easy to sufficiently increase the mechanical strength (such as flexural strength) of the molded article, and when it is 1.2 dl / g or less, the fluidity during molding of the resin composition is less likely to be impaired. The intrinsic viscosity [η] can be adjusted by adjusting the molar ratio of the component unit (Aa) derived from dicarboxylic acid and the component unit (Ab) derived from diamine. Specifically, the closer the molar ratio of the component unit (Aa) derived from carboxylic acid and the component unit (Ab) derived from diamine is to 1:1, the higher the intrinsic viscosity can be increased. It can also be adjusted by the amount of end capping of the semi-aromatic polyamide resin (A), etc.

[0057] The intrinsic viscosity [η] of the semi-aromatic polyamide resin (A) can be measured as follows. Dissolve 0.5 g of the polyamide resin (A) in 50 ml of a 96.5% sulfuric acid solution to obtain a sample solution. Measure the flow-down seconds of the obtained solution under the condition of 25°C ± 0.05°C using an Ubbelohde viscometer, and calculate based on the following formula. [η]=ηSP / (C*(1 + 0.205ηSP)) [η]: Intrinsic viscosity (dl / g) ηSP: Specific viscosity C: Sample concentration (g / dl) t: Flow-down seconds of the sample solution (seconds) t0: Flow-down seconds of the blank sulfuric acid (seconds) ηSP=(t - t0) / t0

[0058] The semi-aromatic polyamide resin (A) can be produced in the same manner as known polyamide resins. For example, it can be produced by polycondensing a dicarboxylic acid and a diamine in a homogeneous solution. Specifically, a lower condensate can be obtained by heating a dicarboxylic acid and a diamine in the presence of a catalyst as described in WO 03 / 085029, and then polycondensing by applying a shear stress to the melt of this lower condensate.

[0059] The content of the semi-aromatic polyamide resin (A) is preferably 20% by mass or more and 80% by mass or less, more preferably 30% by mass or more and 70% by mass or less, and even more preferably 35% by mass or more and 60% by mass or less, based on the total mass of the polyamide resin composition. When the above content is 20% by mass or more, the flexural strength and toughness of the polyamide resin composition can be further increased. When the above content is 80% by mass or less, other components such as the fibrous reinforcing material (B) and the flame retardant described later can be sufficiently contained in the polyamide resin composition.

[0060] 1-2. Fibrous reinforcing material (B) In the present embodiment, the fibrous reinforcing material (B) includes a reinforcing material (B-1) having an aspect ratio of the cross-section of 1.5 or more (hereinafter simply referred to as "reinforcing material (B-1)") and a reinforcing material (B-2) having an aspect ratio of the cross-section of less than 1.5 (hereinafter simply referred to as "reinforcing material (B-2)"). In this specification, the "cross-section" of the fibrous reinforcing material (B) refers to the cross-section cut in a direction perpendicular to the length direction of the fiber. The "aspect ratio" refers to the value of the first line segment / the second line segment when, among the line segments connecting the mutually opposing edges in the above cross-section passing through the center of the above cross-section, the longest line segment is defined as the first line segment and the line segment perpendicular to the longest line segment is defined as the second line segment.

[0061] (Reinforcing material (B-1)) The reinforcing material (B-1) preferably has an aspect ratio of the cross-section of 2.0 or more, more preferably 3.0 or more, and even more preferably 4.0 or more. When the aspect ratio is 2.0 or more, the length in the direction orthogonal to the length direction of the reinforcing material (B-1) (the flow direction of the polyamide resin composition during molding) becomes larger. Therefore, in addition to the volume shrinkage in the flow direction of the molded body, the volume shrinkage in the orthogonal direction can be more suppressed. As a result, the difference in volume shrinkage rate between the flow direction and the orthogonal direction can be further reduced, and the warpage of the molded body immediately after molding and after the reflow treatment can be more suppressed. For the same reason, when the aspect ratio is 3.0 or more, the warpage can be more sufficiently suppressed. The upper limit value of the aspect ratio is, for example, 8.0. The aspect ratio can be obtained by determining the weight average major axis diameter (Dw) and the weight average minor axis diameter (dw) by the method described later and calculating their ratio (Dw / dw). The shape of the cross-section of the reinforcing material (B-1) is, for example, elliptical and flat.

[0062] The type of the reinforcing material (B-1) is not particularly limited. For example, it includes glass fiber, carbon fiber, wollastonite, potassium titanate whisker, calcium carbonate whisker, aluminum borate whisker, magnesium sulfate whisker, sepiolite, zonnolite, zinc oxide whisker, mild fiber, cut fiber, wholly aromatic polyamide fiber (for example, polyparaphenylene terephthalamide fiber, polymetaphenylene terephthalamide fiber, polyparaphenylene isophthalamide fiber, polymetaphenylene isophthalamide fiber, and fiber obtained from a condensate of diaminodiphenyl ether and terephthalic acid or isophthalic acid, etc.), boron fiber, liquid crystal polyester fiber, etc. Among these, glass fiber and carbon fiber are preferred, and glass fiber is more preferred because they can easily enhance the strength (rigidity) and heat resistance of the obtained polyamide resin composition.

[0063] The average fiber diameter (weight average major axis (Dw)) of the reinforcing material (B-1) is, for example, 1 μm or more and 50 μm or less, preferably 5 μm or more and 30 μm or less. The average fiber length of the reinforcing material (B-1) is, for example, 10 μm or more and 3000 μm or less, preferably 100 μm or more and 1000 μm or less. In this specification, the "fiber diameter" refers to the length of the longest line segment (the first line segment above) among the line segments connecting opposite edges in the cross-section of the fibrous reinforcing agent.

[0064] The average fiber length of the reinforcing material (B-1) can be measured by the following method. 1) After dissolving the polyamide resin composition in a hexafluoroisopropanol / chloroform solution (0.1 / 0.9% by volume), collect the filtrate obtained by filtration. 2) Disperse the filtrate obtained in 1) above in water, and measure the major axis and minor axis (let the major axis be Di and the minor axis be di. Here, the major axis refers to the first line segment in the fiber cross-section, and the minor axis refers to the second line segment) and the fiber length (Li) of 300 arbitrary fibers each with an optical microscope (magnification: 50 times). Let the number of fibers with a fiber length of Li be qi, and calculate the weight average length (Lw) based on the following formula, and take this as the average fiber length of the reinforcing material (B-1). Weight average length (Lw) = (Σqi × Li 2 ) / (Σqi × Li) Similarly, let the number of fibers with a major axis of Di be Ri and the number of fibers with a minor axis of di be ri, and calculate the weight average diameter (weight average major axis Dw, weight average minor axis dw) based on the following formula, and take this as the average major axis and average minor axis of the reinforcing material (B-1). Weight average major axis (Dw) = (ΣRi × Di 2 ) / (ΣRi × Di) Weight average minor axis (dw) = (Σri × di 2 ) / (Σri × di)

[0065] The content of the reinforcing material (B-1) is 15% by mass or more and 85% by mass or less, preferably 30% by mass or more and 85% by mass or less, more preferably 40% by mass or more and 85% by mass or less, still more preferably 50% by mass or more and 85% by mass or less, and particularly preferably 50% by mass or more and 70% by mass or less with respect to the total mass of the reinforcing material (B-1) and the reinforcing material (B-2). When the above content is 50% by mass or more, in addition to the volume shrinkage of the molded body in the above flow direction, the volume shrinkage in the above orthogonal direction can be more suppressed. As a result, the warpage of the molded body immediately after molding and after the reflow treatment can be more suppressed.

[0066] (Reinforcing material (B-2)) The reinforcing material (B-2) preferably has an aspect ratio of the cross section of 1.0 or more and less than 1.5, and more preferably 1.0 or more and 1.3 or less. The aspect ratio of the reinforcing material (B-2) can be determined in the same manner as the reinforcing material (B-1). The cross-sectional shape of the reinforcing material (B-2) is, for example, elliptical and circular, and preferably circular.

[0067] The type of the reinforcing material (B-2) is not particularly limited. For example, it includes glass fiber, carbon fiber, wollastonite, potassium titanate whisker, calcium carbonate whisker, aluminum borate whisker, magnesium sulfate whisker, sepiolite, zonnolite, zinc oxide whisker, mild fiber, cut fiber, wholly aromatic polyamide fiber (for example, polyparaphenylene terephthalamide fiber, polymetaphenylene terephthalamide fiber, polyparaphenylene isophthalamide fiber, polymetaphenylene isophthalamide fiber, and fiber obtained from the condensate of diaminodiphenyl ether and terephthalic acid or isophthalic acid, etc.), boron fiber, liquid crystal polyester fiber, etc. Among these, glass fiber and carbon fiber are preferred, and glass fiber is more preferred because it is easy to increase the strength (rigidity) and heat resistance of the obtained polyamide resin composition.

[0068] The average fiber diameter (weight average major axis (Dw)) of the reinforcing material (B-2) is, for example, 1 μm or more and 50 μm or less, preferably 5 μm or more and 30 μm or less, and more preferably 5 μm or more and 20 μm or less. Further, the average fiber length of the reinforcing material (B-2) is, for example, 500 μm or more and 10 mm or less, preferably 700 μm or more and 5 mm or less. The above average fiber diameter and the above average fiber length can be measured in the same manner as the method described for the reinforcing material (B-1).

[0069] The content of the fibrous reinforcing material (B-2) is 15% by mass or more and 85% by mass or less, preferably 15% by mass or more and 70% by mass or less, more preferably 15% by mass or more and 60% by mass or less, still more preferably 15% by mass or more and 50% by mass or less, and even more preferably 30% by mass or more and 50% by mass or less, based on the total mass of the reinforcing material (B-1) and the reinforcing material (B-2).

[0070] The fibrous reinforcing material (B) may be converged by a converging agent. Examples of the converging agent include acrylic, acrylic / maleic acid modified, epoxy, urethane, urethane / maleic acid modified, and urethane / epoxy modified compounds, and the converging agent may be used alone or in combination. Among these, the urethane type is preferred.

[0071] The content of the fibrous reinforcing material (B) is preferably 20% by mass or more and 40% by mass or less, more preferably 25% by mass or more and 35% by mass or less, based on the total mass of the polyamide resin composition. When the above content is 20% by mass or more, the strength of the molded body of the polyamide resin composition can be further increased. As a result, the molded body is less likely to be deformed during the reflow process, and blisters are less likely to occur. Consequently, the reflow heat resistance can be further enhanced. Also, when the above content is 40% by mass or less, the total contact area between the semi-aromatic polyamide resin (A) and the fibrous reinforcing material (B) can be reduced. Thereby, the area of the interface between the fibrous reinforcing material, which is a fragile layer, and the polyamide resin can be decreased, so that the occurrence of blisters at the interface between the semi-aromatic polyamide resin (A) and the fibrous reinforcing material (B) can be suppressed. That is, it is considered that when the above content is 40% by mass or less, blisters are less likely to occur.

[0072] 1-3. Other Components The polyamide resin composition may contain other known components.

[0073] Examples of other components include flame retardants, flame retardant aids, nucleating agents, lubricants, drip preventives, halogen scavengers, colorants, heat stabilizers, corrosion resistance improvers, drip preventives, ion scavengers, elastomers (rubbers), antistatic agents, mold release agents, antioxidants (such as phenols, amines, sulfurs, and phosphors), heat stabilizers other than the above (such as lactone compounds, vitamin Es, hydroquinones, etc.), light stabilizers (such as benzotriazoles, triazines, benzophenones, benzoates, hindered amines, and oxanilides, etc.), and other polymers (such as olefin copolymers such as polyolefins, ethylene-propylene copolymers, ethylene-1-butene copolymers, etc., olefin copolymers such as propylene-1-butene copolymers, polystyrene, polycarbonate, polyacetal, polysulfone, polyphenylene oxide, fluororesins, silicone resins, and LCP, etc.).

[0074] (Flame Retardant) Examples of the flame retardant include halogen-containing compounds and phosphinate compounds. Examples of the halogen-containing compounds include brominated polystyrene, polybrominated styrene, brominated polyphenylene ether, and the like. Examples of the phosphinate compounds are the compounds represented by the following formula (I) and formula (II).

[0075] [Chemical formula]

[0076] In formula (I) and formula (II), R 1 and R 2 are each independently a linear or branched alkyl group or aryl group having 1 to 6 carbon atoms. R 3 is a linear or branched alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 10 carbon atoms, an alkylarylene group having 6 to 10 carbon atoms, or an arylalkylene group having 6 to 10 carbon atoms. M is Mg, Ca, Al, Sb, Sn, Ge, Ti, Zn, Fe, Zr, Ce, Bi, Sr, Mn, Li, Na, K, and / or a protonated nitrogen base. m, n, and x are each independently an integer of 1 to 4.

[0077] Specific examples of the phosphinate compounds include calcium dimethylphosphinate, magnesium dimethylphosphinate, aluminum dimethylphosphinate, zinc dimethylphosphinate, calcium ethylmethylphosphinate, magnesium ethylmethylphosphinate, aluminum ethylmethylphosphinate, zinc ethylmethylphosphinate, calcium diethylphosphinate, magnesium diethylphosphinate, aluminum diethylphosphinate, zinc diethylphosphinate, calcium methyl-n-propylphosphinate, magnesium methyl-n-propylphosphinate, aluminum methyl-n-propylphosphinate, zinc methyl-n-propylphosphinate, calcium methanedi(methylphosphinate), magnesium methanedi(methylphosphinate), aluminum methanedi(methylphosphinate), zinc methanedi(methylphosphinate), calcium benzene-1,4-(dimethylphosphinate), magnesium benzene-1,4-(dimethylphosphinate), aluminum benzene-1,4-(dimethylphosphinate), zinc benzene-1,4-(dimethylphosphinate), calcium methylphenylphosphinate, magnesium methylphenylphosphinate, aluminum methylphenylphosphinate, zinc methylphenylphosphinate, calcium diphenylphosphinate, magnesium diphenylphosphinate, aluminum diphenylphosphinate, zinc diphenylphosphinate, and the like. Preferably, they are calcium dimethylphosphinate, aluminum dimethylphosphinate, zinc dimethylphosphinate, calcium ethylmethylphosphinate, aluminum ethylmethylphosphinate, zinc ethylmethylphosphinate, calcium diethylphosphinate, aluminum diethylphosphinate, zinc diethylphosphinate; more preferably, it is aluminum diethylphosphinate.

[0078] (Flame Retardant Aid) Examples of the flame retardant aid include metal oxides and metal hydroxides. Specifically, zinc borate, boehmite, zinc stannate, iron oxide, zinc oxide, tin oxide are preferred, and more preferably zinc borate.

[0079] The content of the flame retardant is preferably 0.5% by mass or more and 5.0% by mass or less, more preferably 1.0% by mass or more and 3.0% by mass or less, based on the total mass of the polyamide resin composition.

[0080] (Nucleating agent) The nucleating agent can promote the crystallization of the semi-aromatic polyamide resin (A). Therefore, the tensile strength and modulus of elasticity of the resin member can be further increased.

[0081] Examples of the nucleating agent include metal salt-based compounds such as sodium 2,2-methylenebis(4,6-di-t-butylphenyl) phosphate, aluminum tris(p-t-butylbenzoate), and stearates; sorbitol-based compounds such as bis(p-methylbenzylidene)sorbitol and bis(4-ethylbenzylidene)sorbitol; and inorganic substances such as talc, calcium carbonate, and hydrotalcite. Among these, talc is preferred from the viewpoint of further increasing the crystallinity of the resin member. These nucleating agents may be used alone or in combination of two or more.

[0082] Talc generally contains magnesium hydrosilicate (SiO2: 58 - 64%, MgO: 28 - 32%, Al2O3: 0.5 - 5%, Fe2O3: 0.3 - 5%) as the main component. The average particle size of talc is not particularly limited, but is preferably 1 - 15 μm. When the average particle size of talc is within the above range, it is easy to disperse talc in the polyamide resin (A) without impairing the fluidity of the polyamide resin composition. From the same viewpoint, the average particle size of talc is more preferably 1 - 7.5 μm. The average particle size of talc can be measured by the laser diffraction method, for example, the laser diffraction method using a Shimadzu particle size distribution analyzer (SALD-2000A type) manufactured by Shimadzu Corporation.

[0083] The content of the nucleating agent is preferably 0.10 parts by mass or more and 5.00 parts by mass or less, more preferably 0.10 parts by mass or more and 3.00 parts by mass or less, based on the total mass of the polyamide resin composition. When the content of the nucleating agent is within the above range, it is easy to sufficiently increase the crystallinity of the resin member, and sufficient mechanical strength can be easily obtained.

[0084] (Lubricant) The lubricant improves the injection fluidity of the polyamide resin composition and improves the appearance of the resulting resin member. The lubricant can be a fatty acid metal salt such as a metal salt of oxycarboxylic acid and a metal salt of higher fatty acid.

[0085] The oxycarboxylic acid constituting the above metal salt of oxycarboxylic acid may be an aliphatic oxycarboxylic acid or an aromatic oxycarboxylic acid. Examples of the above aliphatic oxycarboxylic acids include aliphatic oxycarboxylic acids having 10 to 30 carbon atoms such as α-hydroxymyristic acid, α-hydroxypalmitic acid, α-hydroxystearic acid, α-hydroxyeicosanoic acid, α-hydroxydocosanoic acid, α-hydroxytetraeicosanoic acid, α-hydroxyhexaeicosanoic acid, α-hydroxyoctaeicosanoic acid, α-hydroxytriacontanoic acid, β-hydroxymyristic acid, 10-hydroxydecanoic acid, 15-hydroxypentadecanoic acid, 16-hydroxyhexadecanoic acid, 12-hydroxystearic acid, and ricinoleic acid. Examples of the above aromatic oxycarboxylic acids include salicylic acid, m-hydroxybenzoic acid, p-hydroxybenzoic acid, gallic acid, mandelic acid, and tropic acid.

[0086] Examples of the metal constituting the above metal salt of oxycarboxylic acid include alkali metals such as lithium, and alkaline earth metals such as magnesium, calcium, and barium.

[0087] Among these, the metal salt of oxycarboxylic acid is preferably a metal salt of 12-hydroxystearic acid, more preferably magnesium 12-hydroxystearate and calcium 12-hydroxystearate.

[0088] Examples of the higher fatty acid constituting the above-mentioned metal salt of higher fatty acid include higher fatty acids having 15 to 30 carbon atoms such as stearic acid, oleic acid, behenic acid, docosanoic acid, and montanic acid.

[0089] Examples of the metal constituting the above-mentioned metal salt of higher fatty acid include calcium, magnesium, barium, lithium, aluminum, zinc, sodium, potassium, and the like.

[0090] Among these, the above-mentioned metal salt of higher fatty acid is preferably calcium stearate, magnesium stearate, barium stearate, calcium behenate, sodium montanate, and calcium montanate.

[0091] The content of the lubricant is preferably 0.01% by mass or more and 1.30% by mass or less based on the total mass of the polyamide resin composition. When the content of the lubricant is 0.01% by mass or more, the fluidity during molding is likely to increase, and the appearance of the resulting molded product is likely to improve. When the content of the lubricant is 1.30% by mass or less, gas generated by the decomposition of the lubricant is less likely to be generated during molding, and the appearance of the product is likely to be good.

[0092] (Drip inhibitor) The drip inhibitor is an additive for suppressing the dripping of resin droplets in the combustion test of the molded body of the polyamide resin composition (for example, the test of UL94 standard (1991)). Examples of the drip inhibitor include maleic acid-modified styrene-ethylene-butylene-styrene (SEBS) copolymer, fluororesin, and the like.

[0093] (Halogen scavenger) The halogen scavenger is preferably contained in the polyamide resin composition when a halogen-containing compound is used as the above-mentioned flame retardant. The halogen scavenger can capture halide ions generated when the molded body of the polyamide resin composition containing the halogen-containing compound is burned, and suppress the generation of harmful substances. Examples of the halogen scavenger include hydrotalcite and the like.

[0094] 1-4. Method for producing polyamide resin composition The polyamide resin composition can be produced by mixing the above-mentioned semi-aromatic polyamide resin (A), fibrous reinforcing material (B), phosphinate compound (C) and, if necessary, other components by a known resin kneading method, such as a Henschel mixer, V blender, ribbon blender, or tumbler blender, or by melt-kneading with a single-screw extruder, multi-screw extruder, kneader, or Banbury mixer after mixing and then granulating or pulverizing. At this time, the melting temperature during melt-kneading is preferably not less than the melting point (Tm) + 10°C of the semi-aromatic polyamide resin (A) and not more than the melting point (Tm) + 20°C of the semi-aromatic polyamide resin (A).

[0095] 1-5. Physical properties of polyamide resin composition In the polyamide resin composition of this embodiment, the heat of fusion (ΔH) measured by a differential scanning calorimeter (DSC) is preferably 5 J / g or more, more preferably 10 J / g or more, still more preferably 15 J / g or more, particularly preferably 20 J / g or more, and most preferably 25 J / g or more. When the heat of fusion (ΔH) of the polyamide resin composition is 5 J / g or more, the crystallinity of the polyamide resin composition can be further enhanced, and the reflow heat resistance of the molded article can be further enhanced. For the same reason, when the above heat of fusion (ΔH) is 10 J / g or more, the reflow heat resistance of the molded article can be more sufficiently enhanced. The upper limit value of the above heat of fusion (ΔH) is not particularly limited, but is, for example, 100 J / g, preferably 80 J / g, and more preferably 60 J / g.

[0096] The heat of fusion (ΔH) of the polyamide resin composition can be measured using a differential scanning calorimeter (DSC220C type, manufactured by Seiko Instruments Inc.).

[0097] Specifically, about 5 mg of the polyamide resin composition is sealed in a measurement aluminum pan and heated from room temperature to 350 °C at 10 °C / min. To completely melt the resin, it is held at 350 °C for 3 minutes and then cooled to 30 °C at 10 °C / min. The heat of fusion (ΔH) of the polyamide resin composition is determined from the area of the endothermic peak during melting in the above-mentioned heating process in accordance with JIS K7122.

[0098] 2. Molded article The molded article of the present invention is formed by molding the polyamide resin composition of the present invention. With the above-mentioned polyamide resin composition, the reflow heat resistance is enhanced, and the warpage of the molded article after molding and after the reflow treatment is suppressed.

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

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

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

Examples

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

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

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

[0105] The limiting viscosity [η] of the obtained polyamide resin PA-1 was 0.8 dl / g, the melting point (Tm) was 320°C, the glass transition temperature (Tg) was 95°C, and the heat of fusion (ΔH) was 49 J / g. Also, the composition of the obtained polyamide resin PA-1 was such that the content of the component unit derived from terephthalic acid was 62.5 mol% and the content of the component unit derived from adipic acid was 37.5 mol% with respect to the total number of moles of the component units derived from dicarboxylic acids, and the content of the component unit derived from 1,6-diaminohexane was 100 mol% with respect to the total number of moles of the component units derived from diamines.

[0106] 1-2. Fibrous Reinforcing Material (B) 1-2-1. Reinforcing Material (B-1) Reinforcing Material (B-1a): Glass Fiber (CSG-3PA820S, manufactured by Nitto Boseki Co., Ltd., aspect ratio of cross-sectional shape: 4) Reinforcing Material (B-1b): Glass Fiber (CSG 3PL-810, manufactured by Nitto Boseki Co., Ltd., aspect ratio of cross-sectional shape: 2)

[0107] 1-2-2. Reinforcing Material (B-2) Glass Fiber (ECS03-615, manufactured by Central Glass Co., Ltd., aspect ratio of cross-sectional shape: 1)

[0108] 1-3. Other Components 1-3-1. Flame Retardant Brominated Polystyrene (manufactured by Albemarle Corporation, HP-3010, bromine content: 68% by mass, number average molecular weight (Mn): 3400, weight average molecular weight (Mw): 4000, Mw / Mn: 1.2)

[0109] 1-3-2. Flame Retardant Aid Sodium Antimonate (manufactured by Nippon Mining & Metals Co., Ltd., SA-A)

[0110] 1-3-3. Nucleating Agent Talc (manufactured by Matsumura Sangyo Co., Ltd., High Filler #5000PJ, average particle diameter 4.5 μm)

[0111] 1-3-4. Lubricant Calcium Montanate (manufactured by Clariant Japan Ltd., Licomont CAV102)

[0112] 1-3-5. Drip Suppressant m-SEBS (Maleated SEBS, manufactured by Asahi Chemical Industry Co., Ltd., Tough Tech M1913)

[0113] 1-3-6. Halogen Scavenger Hydrotalcite (manufactured by Toda Kogyo Corporation, NAOX-33)

[0114] 2. Measurement The physical properties of each of the above resins were measured by the following methods.

[0115] <Melting point (Tm), glass transition temperature (Tg)> The melting point (Tm) and glass transition temperature (Tg) of the polyamide resin were measured using differential scanning calorimetry (DSC220C type, manufactured by Seiko Instruments Inc.). Specifically, approximately 5 mg of the polyamide resin was sealed in a measurement aluminum pan and set for differential scanning calorimetry. Then, it was heated from room temperature to 350 °C at a rate of 10 °C / min. To completely melt the resin, it was held at 350 °C for 3 minutes and then cooled to 30 °C at a rate of 10 °C / min. After leaving it at 30 °C for 5 minutes, the second heating was carried out from 30 °C to 350 °C at a rate of 10 °C / min. The temperature (°C) of the endothermic peak in this second heating was defined as the melting point (Tm) of the polyamide resin, and the inflection point corresponding to the glass transition was defined as the glass transition temperature (Tg).

[0116] <Heat of fusion (ΔH)> The heat of fusion (ΔH) of the polyamide resin was determined from the area of the exothermic peak of crystallization in the first heating process in accordance with JIS K 7122 (2012).

[0117] <Limiting viscosity [η]> The limiting viscosity [η] of the polyamide resin was measured by dissolving 0.5 g of the polyamide resin in 50 ml of a 96.5% sulfuric acid solution and measuring the flow-down seconds of the resulting solution under the condition of 25 °C ± 0.05 °C using an Ubbelohde viscometer, and calculated based on the formula: [η] = ηSP / (C(1 + 0.205ηSP)). [η]: Limiting viscosity (dl / g) ηSP: Specific viscosity C: Sample concentration (g / dl) t: Flow-down seconds of the sample solution (seconds) t0: Flow-down seconds of the blank sulfuric acid (seconds) ηSP = (t - t0) / t0

[0118] 3. Preparation of polyamide resin composition The above materials were mixed in a tumbler blender at the composition ratios (unit: parts by mass) shown in Table 1, and melt-kneaded at a cylinder temperature of 300 to 335 °C using a vented twin-screw extruder with a diameter of 30 mm. Then, the kneaded material was extruded into strands and cooled in a water bath. Thereafter, the strands were taken up by a pelletizer and cut to obtain pelletized polyamide resin compositions 1 to 7.

[0119] <Heat of fusion of polyamide resin composition> The heat of fusion (ΔH) of each polyamide resin composition was measured using a differential scanning calorimeter (DSC220C type, manufactured by Seiko Instruments Inc.).

[0120] Specifically, about 5 mg of the polyamide resin composition was sealed in a measurement aluminum pan and heated from room temperature to 350 °C at 10 °C / min. To completely melt the resin composition, it was held at 360 °C for 3 minutes, then cooled to 30 °C at 10 °C / min. After leaving it at 30 °C for 5 minutes, the second heating was carried out from 30 °C to 360 °C at 10 °C / min. Then, the heat of fusion (ΔH) of the polyamide resin composition was determined from the area of the endothermic peak of crystallization in the first heating process in accordance with JIS K7122 (2012).

[0121] <Aspect ratio of fibrous reinforcing material (B)> The aspect ratio of the cross-section of the fibrous reinforcing material (B) was determined by measuring the weight average major axis (Dw) and the weight average minor axis (dw) of the fibrous reinforcing material (B) by the following method and calculating Dw / dw. 1) After dissolving the polyamide resin composition in a hexafluoroisopropanol / chloroform solution (0.1 / 0.9% by volume), the filtrate obtained by filtration was collected. 2) Disperse the filtrate obtained in 1) above in water, and measure the major axis and minor axis of any 300 fibers each (let the major axis be Di and the minor axis be di. Here, the major axis refers to the first line segment in the fiber cross-section, and the minor axis refers to the second line segment). Let the number of fibers with a major axis of Di be Ri, and the number of fibers with a minor axis of di be ri, and calculate the weight average diameter (weight average major axis Dw, weight average minor axis dw) based on the following formula. Weight average major axis (Dw) = (ΣRi × Di 2 ) / (ΣRi × Di) Weight average minor axis (dw) = (Σri × di 2 ) / (Σri × di)

[0122] 4. Evaluation <Flexural Strength and Toughness> Test pieces with a length of 64 mm, a width of 6 mm, and a thickness of 0.8 mm were prepared by injection molding. The injection molding machine, the cylinder temperature of the injection molding machine, and the mold temperature are shown below. Injection molding machine: Toshiba TR40S3A (manufactured by Sodick Plastic Co., Ltd.) Injection molding machine cylinder temperature: Melting point of polyamide resin + 10 °C Mold temperature: 120 °C The prepared test pieces were left standing for 24 hours at a temperature of 23 °C under a nitrogen atmosphere. Then, a flexural test was performed using a flexural testing machine (AB5 manufactured by NTESCO) in an atmosphere of 23 °C and 50% relative humidity. The test conditions were a span of 26 mm and a flexural speed of 5 mm / min. From the flexural test, the flexural strength and the energy (toughness) required to break the test piece were measured.

[0123] <Flow Length> Each polyamide resin composition was injection molded under the following conditions using a bar flow mold with a width of 10 mm and a thickness of 0.5 mm, and the flow length (mm) of the resin in the mold was measured. Injection molding machine: Toshiba TR40S3A (manufactured by Sodick Plastic Co., Ltd.) Injection setting pressure: 2000 kg / cm 2 Injection molding machine cylinder temperature: Melting point of polyamide resin + 10 °C Mold temperature: 120 °C

[0124] <Reflow heat resistance temperature> Each polyamide resin composition was injection molded under the following conditions to prepare test pieces with a length of 64 mm, a width of 6 mm, and a thickness of 0.8 mm. Molding machine: Toshiba TR40S3A (manufactured by Sodick Plastics Co., Ltd.) Molding machine cylinder temperature: Melting point of each polyamide resin + 10 °C Mold temperature: 120 °C

[0125] The prepared test pieces were conditioned at a temperature of 40 °C and a relative humidity of 95% for 96 hours. The conditioned test pieces were placed on a glass epoxy substrate with a thickness of 1 mm. A temperature sensor was installed on this substrate. The glass epoxy substrate with the test pieces placed on it was set in an air reflow soldering apparatus (AIS-20-82-C, manufactured by Atech Technotron Co., Ltd.), and the reflow process with the temperature profile shown in Figure 1 was performed. As shown in Figure 1, the temperature was raised to 230 °C at a predetermined speed; then, after heating to a predetermined set temperature (a is 270 °C, b is 265 °C, c is 260 °C, d is 255 °C, e is 235 °C in Figure 1) in 20 seconds; the temperature was then lowered to 230 °C. At this time, the maximum value of the set temperature at which the test pieces did not melt and no blisters occurred on the surface was determined, and this maximum value of the set temperature was defined as the reflow heat resistance temperature.

[0126] <Flame retardancy> Each polyamide resin composition was injection molded under the following conditions to prepare test pieces of 1 / 32 inch × 1 / 2 × 5 inches. Using the prepared test pieces, a vertical burning test was conducted in accordance with the UL94 standard (UL Test No. UL94 dated June 18, 1991) to evaluate the flame retardancy. Molding machine: Toshiba TR40S3A (manufactured by Sodick Plastics Co., Ltd.) Molding machine cylinder temperature: Melting point of polyamide resin + 10 °C Mold temperature: 120 °C

[0127] <Amount of warpage> (Evaluation method) A test piece with a length of 50 mm, a width of 30 mm, and a thickness of 0.6 mm was prepared by injection molding. The preparation conditions of the molded body are shown below. Molding machine: Allrounder 270S (manufactured by Arburg Co., Ltd.) Molding machine cylinder temperature: Melting point of polyamide resin (Tm) + 10 °C Mold temperature: 120 °C Gate position: Center in the 30 mm width direction of the test piece Gate size: Width 2 mm Injection speed: 30 cc / s Injection pressure: 2500 bar (maximum) Holding pressure: 300 bar Holding time: 1 s Cooling time: 15 s The prepared test piece was left at 23 °C for 24 hours. Next, the difference between the minimum height and the maximum height of the test piece when placed on the surface plate was defined as the "warpage amount after molding". Furthermore, the test piece was passed through a reflow furnace with a peak temperature of 260 °C using the same testing machine as the reflow heat resistance test and cooled to 23 °C. The difference between the warpage amount of the test piece after cooling and the warpage amount after molding was defined as the "warpage amount after reflow".

[0128] <Measurement of linear expansion coefficient> The sufficiently dried resin composition was injection molded using an injection molding machine (SE75EV - A, manufactured by Sumitomo Heavy Industries, Ltd.) (molding machine cylinder temperature: melting point of polyamide resin (Tm) + 10 °C, mold temperature: 120 °C) to obtain a multi-purpose test piece type A described in ISO standard 3167. The test piece was cut into 10 mm × 4 mm × 4 mm (thickness) with respect to the flow direction (MD) of the polyamide resin composition during molding and the direction (TD) perpendicular to the flow direction. The linear expansion coefficients in the above flow direction (MD) and the above perpendicular direction (TD) were measured in accordance with ISO 11359 - 2 under the following conditions using an apparatus TMA - SS7100 (manufactured by Seiko Instruments Inc.). Molding machine: SE50DU, manufactured by Sumitomo Heavy Industries, Ltd. Measurement mode: Compression expansion mode Temperature range: 23 °C to 270 °C Test load: 49 mN (5 gf) Heating and cooling rate: 5 °C / min Measurement atmosphere: Nitrogen (100 mL / min) Probe diameter: 2.9 mm φ Number of tests n: n = 3 Vacuum drying: 110 °C × 10 hr

[0129] Table 1 shows the composition and evaluation results of each polyamide resin composition. The numerical values in the composition of Table 1 represent parts by mass.

[0130] [Table 1]

[0131] From the results of polyamide resin compositions 1 to 4, it was found that when the content of the reinforcing material (B-1) is 15% by mass or more and 85% by mass or less based on the total mass of the reinforcing material (B-1) and the reinforcing material (B-2), the reflow heat resistance of the molded body can be enhanced while suppressing the warpage of the molded body immediately after molding and after reflow.

Industrial Applicability

[0132] The polyamide resin composition of the present invention can enhance the reflow heat resistance of the molded body while suppressing the warpage of the molded body immediately after molding and after reflow. Therefore, the present invention is useful, for example, in the field of electronic components.

Claims

1. A semi-aromatic polyamide resin (A) having a melting point of 280°C or higher as measured by a differential scanning calorimeter (DSC), and a fibrous reinforcing material (B), wherein the fibrous reinforcing material (B) includes a reinforcing material (B-1) having an aspect ratio of the cross section of 1.5 or more and a reinforcing material (B-2) having an aspect ratio of the cross section of less than 1.5, wherein the content of the reinforcing material (B-1) is 15% by mass or more and 85% by mass or less based on the total mass of the reinforcing material (B-1) and the reinforcing material (B-2), a polyamide resin composition.

2. wherein the content of the reinforcing material (B-1) is 50% by mass or more and 83% by mass or less based on the total mass of the reinforcing material (B-1) and the reinforcing material (B-2), the polyamide resin composition according to Claim 1.

3. wherein the aspect ratio of the cross section of the reinforcing material (B-1) is 3.0 or more, the polyamide resin composition according to Claim 1.

4. wherein the content of the fibrous reinforcing material (B) is 20% by mass or more and 40% by mass or less based on the total mass of the polyamide resin composition, the polyamide resin composition according to Claim 1.

5. wherein the heat of fusion (ΔH) measured by a differential scanning calorimeter (DSC) is 10 J / g or more and 100 J / g or less, the polyamide resin composition according to Claim 1.

6. wherein the number of types of polyamide resins contained in the semi-aromatic polyamide resin (A) is one type, the polyamide resin composition according to Claim 1.

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

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