JP7744271B2 - Semi-aromatic polyamide resin composition and molded article thereof - Google Patents

Description

The present invention relates to a semi-aromatic polyamide resin composition and a molded article thereof.

Various semi-aromatic polyamide resin compositions have been known as molding materials. For example, Patent Document 1 discloses a partially aromatic (semi-aromatic) copolyamide containing 40 to 90 weight percent of <A> units derived from terephthalic acid and hexamethylenediamine, 0 to 50 weight percent of <B> units derived from ε-caprolactam, and 0 to 60 weight percent of <C> units derived from adipic acid and hexamethylenediamine, wherein <B> and/or <C> account for at least 10 weight percent of the total, and the copolyamide contains less than 0.5 weight percent triamine. Patent Document 1 states that the partially aromatic copolyamide exhibits good thermoformability while maintaining mechanical strength.

Patent Document 2 discloses a polyamide resin composition comprising a crystalline copolyamide containing a predetermined amount of hexamethylene terephthalamide units and a predetermined amount of a modified or unmodified elastomer selected from a polyolefin elastomer and a diene elastomer. According to Patent Document 2, the polyamide resin composition is said to have excellent mechanical properties, heat resistance, and moldability.

The semi-aromatic polyamide resins described in these documents are significantly lighter than metals and have excellent mechanical strength and heat resistance, making them suitable for use, for example, as resin materials for automobile parts.

Japanese Patent Application Publication No. 2-41318 Japanese Patent Application Publication No. 5-98152

Conventional semi-aromatic polyamide resin compositions have high mechanical strength, but suffer from problems such as low flexibility and low elongation at break. Low elongation at break makes molded articles prone to breakage when assembling them. In response to this, compounding an elastomer, as described in Patent Document 2, can increase the elongation at break of molded articles to a certain extent, but it is not possible to increase the elongation at break sufficiently. Polyamide resin compositions using non-aromatic polyamides also have the characteristic of high elongation at break for molded articles. However, non-aromatic polyamide resin compositions suffer from the problem of low fluidity at high temperatures during molding. This low fluidity places significant restrictions on molding conditions and product shape.

The present invention was made in consideration of the above circumstances, and aims to provide a semi-aromatic polyamide resin composition and molded articles thereof that can produce molded articles with sufficiently high elongation at break and that have high fluidity at high temperatures.

The present invention relates to the following semi-aromatic polyamide resin composition and molded articles thereof.

The semi-aromatic polyamide resin composition of the present invention is a semi-aromatic polyamide resin composition comprising a semi-aromatic polyamide resin (A) having a melting point of 280°C or higher and 330°C or lower as measured by differential scanning calorimetry (DSC), an olefin polymer (B1), and a styrene-based thermoplastic elastomer (B2), wherein the semi-aromatic polyamide resin (A) comprises component units derived from a dicarboxylic acid and component units derived from a diamine, the component units derived from the dicarboxylic acid comprising component units derived from terephthalic acid in an amount of 45 mol% or higher, based on the total number of moles of the component units derived from the dicarboxylic acid, and the component units derived from the diamine comprise component units derived from linear alkyl esters having 4 to 18 carbon atoms, which account for 50 mol% or higher and 100 mol% or lower, based on the total number of moles of the component units derived from the diamine. The semi-aromatic polyamide resin (A) contains component units derived from alkylene diamine and component units derived from a branched alkylene diamine having from 4 to 18 carbon atoms, and the component units are from 0 mol % to 50 mol %. The olefin polymer (B1) contains a modified ethylene-α-olefin copolymer (B1-1) modified with an unsaturated carboxylic acid or a derivative thereof. The average content of component units derived from the unsaturated carboxylic acid or a derivative thereof in the olefin polymer (B1) is from 0.01 mass % to 5.0 mass %, and the total content of the olefin polymer (B1) and the styrene-based thermoplastic elastomer (B2) is from 10 mass % to 30 mass % based on the total mass of the semi-aromatic polyamide resin (A), the olefin polymer (B1), and the styrene-based thermoplastic elastomer (B2).

The molded article of the present invention is obtained by molding the semi-aromatic polyamide resin composition.

The present invention makes it possible to obtain molded articles with sufficiently high elongation at break, and provides semi-aromatic polyamide resin compositions and molded articles thereof that have high fluidity at high temperatures.

Embodiments of the present invention are described in detail below. Note that the present invention is not limited to the following embodiments.

In this specification, numerical ranges expressed using "to" mean ranges that include the numerical values written before and after "to" as the lower and upper limits, respectively. In numerical ranges described in stages in this specification, the upper or lower limit stated in a certain numerical range may be replaced with the upper or lower limit of another numerical range described in stages.

When used in a polyamide resin composition, the olefin polymer (B1) containing the modified ethylene-α-olefin copolymer (B1-1) increases the elongation at break of the molded article. However, according to the inventors' findings, using only the olefin polymer (B1) does not sufficiently increase the elongation at break of the molded article.

In response to this, the present inventors have found that when an olefin polymer (B1) containing a modified ethylene-α-olefin copolymer (B1-1) is combined with a styrene-based thermoplastic elastomer (B2), the elongation at break of the molded article is higher than when the olefin polymer (B1) or the styrene-based thermoplastic elastomer (B2) is used alone. The reason for this is not clear, but is thought to be as follows.

As described above, the use of an olefin polymer (B1) containing a modified ethylene-α-olefin copolymer (B1-1) can increase the elongation at break of a molded article. The styrene-based thermoplastic elastomer (B2) also has the effect of increasing the elongation at break of a molded article. It is believed that using these in combination results in the formation of a structure in which a phase of the styrene-based thermoplastic elastomer (B2) is dispersed within a phase of the olefin polymer (B1), or in which a phase of the olefin polymer (B1) is dispersed around a phase of the styrene-based thermoplastic elastomer (B2). It is believed that these structures are more likely to exist stably in the presence of the semi-aromatic polyamide resin (A). This is believed to enhance the elongation-at-break effect of both the olefin polymer (B1) and the styrene-based thermoplastic elastomer (B2) compared to when either is used alone, resulting in a sufficiently high elongation at break of the molded article.

Furthermore, in the present invention, by using a semi-aromatic polyamide resin (A) in combination with these, the fluidity of the polyamide resin composition at high temperatures can be improved. Furthermore, by using a styrene-based thermoplastic elastomer (B2), which has excellent elasticity, in combination with the olefin polymer (B1), the tensile strength at break and flexural strength of the molded article can also be further improved.

The configuration of the present invention is explained below.

1. Semi-aromatic Polyamide Resin Composition The semi-aromatic polyamide resin composition of the present invention contains at least a semi-aromatic polyamide resin (A), an olefin polymer (B1), and a styrene-based thermoplastic elastomer (B2).

1-1. Semi-aromatic polyamide resin (A)
The semi-aromatic polyamide resin (A) contains a component unit [a] derived from a dicarboxylic acid and a component unit [b] derived from a diamine.

(Component unit [a] derived from dicarboxylic acid)
The dicarboxylic acid-derived component units [a] include terephthalic acid-derived component units. The content of the terephthalic acid-derived component units is 45 mol% or more, preferably 50 mol% or more and 90 mol% or less, and more preferably 50 mol% or more and 80 mol% or less, based on the total number of moles of the dicarboxylic acid-derived component units [a].

The dicarboxylic acid-derived component unit [a] may further include a unit (a-2) derived from an aromatic dicarboxylic acid component other than terephthalic acid or a component unit (a-3) derived from an aliphatic dicarboxylic acid having from 4 to 20 carbon atoms.

Examples of aromatic dicarboxylic acids other than terephthalic acid include isophthalic acid, 2-methylterephthalic acid, and naphthalenedicarboxylic acid. Of these, isophthalic acid is preferred.

The aliphatic dicarboxylic acid is, for example, an aliphatic dicarboxylic acid having an alkylene group with 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.

The total content of units (a-2) derived from an aromatic dicarboxylic acid component other than terephthalic acid and component units (a-3) derived from an aliphatic dicarboxylic acid having from 4 to 20 carbon atoms is from 0 mol% to 55 mol%, preferably from 10 mol% to 50 mol%, and more preferably from 20 mol% to 50 mol%, based on the total number of moles of component units [a] derived from dicarboxylic acids.

For example, the moldability of the semi-aromatic polyamide resin (A) can be further improved by including a small amount of component units (a-3) derived from an aliphatic dicarboxylic acid in the dicarboxylic acid-derived component units [a]. In particular, semi-aromatic polyamide resin (A) containing 55 mol% or less of component units derived from an aliphatic dicarboxylic acid and 45 mol% or more of component units derived from terephthalic acid tends to have a low water absorption rate and a melting point of 280°C or higher. Molded articles obtained from such semi-aromatic polyamide resin (A) exhibit little dimensional change due to water absorption and can also exhibit sufficiently high heat resistance.

In addition to the above-mentioned constituent units, the semi-aromatic polyamide resin (A) may further contain a small amount of constituent units derived from a tribasic or higher polycarboxylic acid, such as trimellitic acid or pyromellitic acid. The content of such polycarboxylic acid-derived constituent units can typically be 0 mol % or more and 5 mol % or less, based on the total number of moles of dicarboxylic acid-derived constituent units [a].

(Diamine-derived component unit [b])
The diamine-derived component unit [b] includes a component unit (b-1) derived from a linear alkylenediamine having from 4 to 18 carbon atoms.

Examples of linear alkylenediamines include 1,4-diaminobutane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, and 1,12-diaminododecane. Of these, 1,6-diaminohexane, 1,8-diaminooctane, 1,10-diaminodecane, and 1,12-diaminododecane are preferred, with 1,6-diaminohexane being more preferred.

The content of component units (b-1) derived from linear alkylenediamines having from 4 to 18 carbon atoms is from 50 mol% to 100 mol%, preferably from 85 mol% to 100 mol%, and more preferably from 90 mol% to 100 mol%, based on the total number of moles of component units [b] derived from diamines.

The diamine-derived component unit [b] may further contain a branched alkylenediamine-derived component unit (b-2) having from 4 to 18 carbon atoms. Unless otherwise specified, the number of carbon atoms in the branched alkylenediamine is the sum of the number of carbon atoms in the main chain alkylene group and the number of carbon atoms in the side chain alkyl group.

Examples of branched alkylene diamines having 4 to 18 carbon atoms include 1-butyl-1,2-diaminoethane, 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, and 2,5-dimethyl-1,6-diamino- Hexane, 2,4-dimethyl-1,6-diamino-hexane, 3,3-dimethyl-1,6-diamino-hexane, 2,2-dimethyl-1,6-diamino-hexane, 2,2,4-trimethyl-1,6-diamino-hexane, 2,4,4-trimethyl-1,6-diamino-hexane, 2,4-diethyl-1,6-diamino-hexane, 2,3-dimethyl-1,7-diamino-heptane, 2,4-dimethyl-1,7-diamino-heptane, 2,5-dimethyl-1,7-diamino-heptane 2,2-dimethyl-1,7-diamino-heptane, 2-methyl-4-ethyl-1,7-diamino-heptane, 2-ethyl-4-methyl-1,7-diamino-heptane, 2,2,5,5-tetramethyl-1,7-diamino-heptane, 3-isopropyl-1,7-diamino-heptane, 3-isooctyl-1,7-diamino-heptane, 2-methyl-1,8-diaminooctane, 1,3-dimethyl-1,8-diamino-octane, 1,4-dimethyl-1,8-diamino-octane These include pentane, 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, branched alkyldiamines having one or two side chain alkyl groups with 1 to 2 carbon atoms and a main chain with 4 to 10 carbon atoms are preferred, with 2-methyl-1,5-diaminopentane being more preferred.

The content of component units (b-2) derived from branched alkylenediamine having 4 to 18 carbon atoms is 0 mol% to 50 mol%, preferably 0 mol% to 15 mol%, and more preferably 0 mol% to 10 mol%.

In this way, by having the diamine-derived component unit [b] contain the component units derived from two specific alkylenediamines in the amounts described above, the melting point of the semi-aromatic polyamide resin (A) can be lowered to a level at which the semi-aromatic polyamide resin composition does not cause gas burning during molding. It is also possible to increase the melt fluidity of the semi-aromatic polyamide resin composition during molding and improve the creep resistance of the molded body at high temperatures.

When the diamine-derived component unit [b] contains both component units (b-1) derived from a linear alkylenediamine having from 4 to 18 carbon atoms and component units (b-2) derived from a branched alkylenediamine having from 4 to 18 carbon atoms, melt fluidity during molding can be further improved if the content of component units (b-1) derived from linear alkylenediamine having from 4 to 18 carbon atoms is 99 mol% or less. Furthermore, if the content of component units (b-2) derived from branched alkylenediamine having from 4 to 18 carbon atoms is 50 mol% or less, the crystallization rate of the semi-aromatic polyamide resin (A) is less likely to slow down, and sufficient heat resistance is likely to be achieved.

Examples of repeating units composed of a component unit [a] derived from a dicarboxylic acid and a component unit [b] derived from a diamine include a repeating unit represented by the following formula [I-a]: In the following formula, ^R1 is an alkylene group having from 4 to 18 carbon atoms.

It is not necessary for all of the repeating units constituting the semi-aromatic polyamide resin (A) to be the repeating units represented by [I-a] above; the semi-aromatic polyamide resin (A) may further contain repeating units in which some of the component units (a-1) derived from terephthalic acid as described above have been replaced with other dicarboxylic acid components.

As described above, examples of component units derived from dicarboxylic acids other than terephthalic acid include component units (a-2) derived from aromatic dicarboxylic acids other than terephthalic acid and component units (a-3) derived from aliphatic dicarboxylic acids.

The repeating unit having the component unit (a-2) derived from an aromatic dicarboxylic acid other than terephthalic acid is preferably a repeating unit having a component unit derived from isophthalic acid, and can be represented by the following formula [I-b], where R ¹ is as defined above.

A repeating unit having a component unit (a-3) derived from an aliphatic dicarboxylic acid can be represented by the following formula [II]: In the following formula, ^R1 is as defined above, and n generally represents an integer of 4 or more and 20 or less, and preferably an integer of 6 or more and 12 or less.

The repeating units constituting the semi-aromatic polyamide resin (A) may have, as diamine-derived component units [b], component units (b-1) derived from a linear alkylenediamine having from 4 to 18 carbon atoms and component units (b-2) derived from a branched alkylenediamine having from 4 to 18 carbon atoms. In this case, the repeating units having component units derived from a branched alkyldiamine are preferably repeating units having component units derived from 2-methyl-1,5-diaminopentane, and can be represented by the following formula [III]: In the following formula, ^R2 is a divalent hydrocarbon group such as a p-phenylene group, an m-phenylene group, or an alkylene group, provided that from 45 mol % to 100 mol % of R2 is a p-phenylene group.

The intrinsic viscosity [η] of the semi-aromatic polyamide resin (A), measured in concentrated sulfuric acid at 25°C, is typically 0.5 dl/g or more and 3.0 dl/g or less, preferably 0.5 dl/g or more and 2.8 dl/g or less, and more preferably 0.6 dl/g or more and 2.5 dl/g or less.

The intrinsic viscosity [η] of the semi-aromatic polyamide resin (A) can be measured as follows: 0.5 g of the semi-aromatic polyamide resin (A) is dissolved in 50 ml of a 96.5% sulfuric acid solution to prepare a sample solution. The flow time of the obtained solution at 25°C ± 0.05°C is measured using an Ubbelohde viscometer, and the intrinsic viscosity [η] is calculated based on the following formula:
[η]=ηSP/(C*(1+0.205ηSP))
[η]: Intrinsic viscosity (dl/g)
ηSP: specific viscosity C: sample concentration (g/dl)
t: number of seconds for the sample solution to flow down (seconds)
t ₀ : Number of seconds (seconds) for blank sulfuric acid to flow
ηSP=(t−t ₀ )/t ₀

Furthermore, the melting point of the semi-aromatic polyamide resin (A) often does not exceed 330°C. That is, the melting point of the semi-aromatic polyamide resin (A) is usually 280°C or higher and 330°C or lower, and preferably 290°C or higher and 305°C or lower. Such semi-aromatic polyamide resin (A) has particularly excellent heat resistance, low water absorption, and little post-crystallization due to annealing of the molded product.

The glass transition temperature of the semi-aromatic polyamide resin (A) is typically 80°C or higher, and preferably 90°C or higher and 150°C or lower.

The melting point (Tm) and glass transition temperature (Tg) of the semi-aromatic polyamide resin (A) can be measured, for example, using a differential scanning calorimeter (DSC220C, manufactured by Seiko Instruments Inc.).

Specifically, approximately 5 mg of semi-aromatic polyamide resin (A) is sealed in a measuring aluminum pan and heated from room temperature to 350°C at 10°C/min. To completely melt the resin, it is held at 350°C for 3 minutes and then cooled to 30°C at 10°C/min. After leaving it at 30°C for 5 minutes, it is heated a second time to 350°C at 10°C/min. The temperature (°C) of the endothermic peak during this second heating is taken as the melting point (Tm) of the crystalline polyamide resin, and the inflection point corresponding to the glass transition is taken as the glass transition temperature (Tg).

The semi-aromatic polyamide resin (A) may be one type, or two or more types. For example, a semi-aromatic polyamide containing, as the dicarboxylic acid-derived component unit [a], component unit (a-1) derived from terephthalic acid but not other component units (a-2) or (a-3), may be combined with a semi-aromatic polyamide resin containing component unit (a-1) derived from terephthalic acid and other component units (a-2) or (a-3).

The semi-aromatic polyamide resin (A) may also be a combination of a semi-aromatic polyamide (A1) that contains, as the diamine-derived component unit [b], a component unit (b-1) derived from a linear alkylenediamine but does not contain a component unit (b-2) derived from a branched alkylenediamine, and a semi-aromatic polyamide resin (A2) that contains a component unit (b-1) derived from a linear alkylenediamine and a component unit (b-2) derived from a branched alkylenediamine. The content ratio (A2/A1) of these components is not particularly limited, but can be, for example, 0/100 to 100/0 (molar ratio), and preferably 50/50 to 100/0 (mass ratio).

Semi-aromatic polyamide resin (A) can be produced by polycondensation of a dicarboxylic acid component and a diamine component. Specifically, semi-aromatic polyamide resin (A) can be produced by blending a dicarboxylic acid component containing terephthalic acid and a diamine component containing a linear alkylenediamine in an aqueous medium, heating the mixture under pressure in the presence of a catalyst such as sodium hypophosphite to produce a polyamide precursor, and then melt-kneading the polyamide precursor. A molecular weight modifier such as benzoic acid can also be added when producing the polyamide precursor.

1-2. Olefin polymer (B1)
The olefin polymer (B1) includes a modified ethylene/α-olefin copolymer (B1-1).

1-2-1. Modified ethylene/α-olefin copolymer (B1-1)
The modified ethylene/α-olefin copolymer (B1-1) is an ethylene/α-olefin copolymer modified with an unsaturated carboxylic acid or a derivative thereof. That is, the modified ethylene/α-olefin copolymer (B1-1) contains a component unit derived from the unsaturated carboxylic acid or a derivative thereof. The modified site of the modified ethylene/α-olefin copolymer (B1-1) (the component unit derived from the unsaturated carboxylic acid or a derivative thereof) easily interacts with the molecular end group (e.g., amino group) of the semi-aromatic polyamide resin (A), and therefore the two have good compatibility.

Component units derived from unsaturated carboxylic acids or their derivatives have functional groups containing heteroatoms, such as carboxylic acid groups, ester groups, ether groups, aldehyde groups, and ketone groups. Of these, component units derived from unsaturated carboxylic acids or their derivatives preferably have a carboxylic acid group, and more preferably a maleic anhydride group.

The content (modification amount) of component units derived from unsaturated carboxylic acids or derivatives thereof in the modified ethylene-α-olefin copolymer (B1-1) may be set so that the average content (average modification amount) of component units derived from unsaturated carboxylic acids or derivatives thereof in the olefin polymer (B1) falls within the range described below. It is preferably 0.05% by mass or more and 5.0% by mass or less, relative to the modified ethylene-α-olefin copolymer (B1-1). A modification amount of 0.05% by mass or more allows for sufficient interaction with the semi-aromatic polyamide resin (A), thereby enhancing compatibility. Furthermore, a modification amount of 5.0% by mass or less prevents excessive increases in melt viscosity due to excessive interaction, thereby preventing a decrease in fluidity at high temperatures. From the same perspective, the modification amount is preferably 0.1% by mass or more and 3.0% by mass or less, more preferably 0.1% by mass or more and 2.0% by mass or less, and even more preferably 0.3% by mass or more and 2% by mass or less, relative to the modified ethylene-α-olefin copolymer (B1-1).

The content of component units derived from unsaturated carboxylic acid or derivatives thereof in the modified ethylene/α-olefin copolymer (B1-1) can be calculated from the charge ratio when preparing the modified ethylene/α-olefin copolymer (B1-1), or can be measured by NMR.

In the case of ^1H -NMR measurement, for example, a nuclear magnetic resonance spectrometer (ECX400 manufactured by JEOL Ltd.) is used, the solvent is deuterated ortho-dichlorobenzene, the sample concentration is 20 mg/0.6 mL, the measurement temperature is 120°C, the observation nucleus is ^1H (400 MHz), the sequence is single pulse, the pulse width is 5.12 μsec (45° pulse), the repetition time is 7.0 seconds, and the number of accumulations is 500 or more. The reference chemical shift is set to 0 ppm for hydrogen in tetramethylsilane, but similar results can also be obtained by setting the peak derived from the residual hydrogen in deuterated ortho-dichlorobenzene at 7.10 ppm as the reference value for the chemical shift. Peaks such as ^1H derived from functional group-containing compounds can be assigned by conventional methods.

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

The density of the modified ethylene/α-olefin copolymer (B1-1), measured in accordance with JIS K7112:1999, is preferably 0.800 g/cm ^or more and ^less than 0.890 g/cm. When the density of the modified ethylene/α-olefin copolymer (B1-1) is 0.800 g/cm ^{or more} , the strength of the resulting molded article is less likely to be impaired, and when it is ^less than 0.890 g/cm, the resulting molded article is imparted with appropriate flexibility and can be increased in elongation at break. From the same viewpoint, the density of the modified ethylene/α-olefin copolymer (B1-1) is more preferably 0.830 g/cm ^{or more} and less than 0.890 g/ ^cm , even more preferably 0.850 g/cm ^or more and ^less than 0.890 g/cm, and most preferably 0.860 g/cm ^or more and less ^than 0.890 g/cm. The density can be adjusted by the composition of ethylene and α-olefin, the polymerization temperature, hydrogen concentration, etc. during synthesis of the ethylene-α-olefin copolymer, which is the raw material.

The MFR (Melt Flow Rate) of the modified ethylene/α-olefin copolymer (B1-1) is preferably 0.05 g/10 min or more, as measured according to ASTM D1238 at 190°C under a load of 2.16 kg. An MFR of 0.05 g/10 min or more can further enhance the fluidity of the semi-aromatic polyamide resin composition at high temperatures. The upper limit of the MFR is not particularly limited, but is preferably 20 g/10 min or less.

As described above, the modified ethylene/α-olefin copolymer (B1-1) is obtained by graft-modifying the raw material ethylene/α-olefin copolymer with an unsaturated carboxylic acid or its derivative.

(Ethylene-α-olefin copolymer)
The ethylene/α-olefin copolymer used as a raw material may be a copolymer of ethylene and an α-olefin having from 3 to 20 carbon atoms. The content of component units derived from ethylene in the ethylene/α-olefin copolymer is, for example, from 70 mol % to 99.5 mol %, and preferably from 80 mol % to 99 mol %.

Examples of α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and 1-decene. Of these, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene are preferred. These α-olefins can be used alone or in combination of two or more. The content of component units derived from α-olefins in the ethylene/α-olefin copolymer is preferably 0.5 mol% to 30 mol% or more, and 1 mol% to 20 mol% or less.

(Unsaturated carboxylic acid or its derivative)
Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, maleic acid, fumaric acid, and itaconic acid. Examples of derivatives of unsaturated carboxylic acids include acid anhydrides, esters, amides, imides, and metal salts, specifically maleic anhydride, itaconic anhydride, citraconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, glycidyl acrylate, maleic acid monoethyl ester, maleic acid diethyl ester, fumaric acid monomethyl ester, fumaric acid dimethyl ester, itaconic acid monomethyl ester, itaconic acid diethyl ester, acrylamide, and methacrylamide. , maleic acid monoamide, maleic acid diamide, maleic acid N-monoethylamide, maleic acid N,N-diethylamide, maleic acid N-monobutylamide, maleic acid N,N-dibutylamide, fumaric acid monoamide, fumaric acid diamide, fumaric acid N-monobutylamide, fumaric acid N,N-dibutylamide, maleimide, N-butylmaleimide, N-phenylmaleimide, sodium acrylate, sodium methacrylate, potassium acrylate, potassium methacrylate, etc. Of these, maleic anhydride is most preferred.

(Graft modification)
The graft modification can be carried out by various conventionally known methods. For example, it may be carried out by a melt modification method in which an ethylene/α-olefin copolymer is melted using an extruder and a graft monomer is added to carry out graft copolymerization, or it may be carried out by a solution modification method in which an ethylene/α-olefin copolymer is dissolved in a solvent and a graft monomer is added to carry out graft copolymerization. In either case, it is preferable to carry out the reaction in the presence of a radical initiator in order to efficiently graft copolymerize the graft monomer.

Examples of radical initiators include organic peroxides and organic peresters, specifically organic peroxides such as benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(peroxidebenzoate)hexyne-3, 1,4-bis(tert-butylperoxyisopropyl)benzene, lauroyl peroxide, tert-butyl peracetate, 2,5-dimethyl-2,5-di(tert- Examples of suitable peroxides include organic peresters such as 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butyl perbenzoate, tert-butyl perphenyl acetate, tert-butyl perisobutyrate, tert-butyl per-sec-octoate, tert-butyl perpivalate, cumyl perpivalate, and tert-butyl perdiethyl acetate, and azo compounds such as azoisobutyronitrile and dimethyl azoisobutyrate. Among these, preferred are dialkyl peroxides such as dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(peroxybenzoate)hexyne-3, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and 1,4-bis(tert-butylperoxyisopropyl)benzene. The radical initiator is typically used in a proportion of 0.001% by mass or more and 1% by mass or less relative to the mass of the ethylene-α-olefin copolymer used as the raw material.

1-2-2. Unmodified ethylene/α-olefin copolymer (B1-2)
The olefin polymer (B1) may contain an unmodified ethylene/α-olefin copolymer (B1-2). The unmodified ethylene/α-olefin copolymer (B1-2) is an ethylene/α-olefin copolymer that has not been graft-modified. The unmodified ethylene/α-olefin copolymer (B1-2) can impart good melt fluidity to the semi-aromatic polyamide resin composition. Therefore, by further combining the unmodified ethylene/α-olefin copolymer (B1-2) with the modified ethylene/α-olefin copolymer (B1-1), the melt fluidity of the semi-aromatic polyamide resin composition can be further improved, compared to using the modified ethylene/α-olefin copolymer (B1-1) alone.

The density and MFR of the unmodified ethylene/α-olefin copolymer (B1-2) can be in the same range as the density of the modified ethylene/α-olefin copolymer (B1-1).

The unmodified ethylene/α-olefin copolymer (B1-2) may be any copolymer having such a density, and is not particularly limited, but may be the same as the ethylene/α-olefin copolymer used as the raw material for the modified ethylene/α-olefin copolymer (B1-1). That is, the composition, density, and MFR of the unmodified ethylene/α-olefin copolymer (B1-2) may be in the same range as the composition, density, and melt flow rate of the ethylene/α-olefin copolymer used as the raw material for the modified ethylene/α-olefin copolymer (B1-1). The unmodified ethylene/α-olefin copolymer (B1-2) may be the same as or different from the ethylene/α-olefin copolymer used as the raw material for the modified ethylene/α-olefin copolymer (B1-1).

1-2-3. Physical Properties The average content (average modification amount) of component units derived from unsaturated carboxylic acids or derivatives thereof in the entire olefin polymer (B1) is preferably 0.01% by mass or more and 5.0% by mass or less. An average content of 0.01% by mass or more facilitates improved dispersibility in the semi-aromatic polyamide resin (A). An average content of 5.0% by mass or less prevents excessive increases in melt viscosity due to excessive interaction between the olefin polymer (B1) and the semi-aromatic polyamide resin (A), making it less likely that fluidity at high temperatures will decrease, and therefore moldability will be less impaired. From the same viewpoint, the average content of component units derived from unsaturated carboxylic acids or derivatives thereof in the olefin polymer (B1) is more preferably 0.05% by mass or more and 5.0% by mass or less, even more preferably 0.10% by mass or more and 3.0% by mass or less, particularly preferably 0.10% by mass or more and 2.0% by mass or less, and most preferably 0.30% by mass or more and 2.0% by mass or less.

In the olefin polymer (B1), functional groups derived from unsaturated carboxylic acids or derivatives thereof react with or interact with the terminal groups of the semi-aromatic polyamide resin (A). Therefore, when the average content of component units having the above functional groups in the olefin polymer (B1) is at a certain level or higher, the semi-aromatic polyamide resin (A) and the olefin polymer (B1) bond or interact with each other, which tends to increase the elongation at break of the resulting molded article. Furthermore, by keeping the average content of component units having the above functional groups at 5.0% by mass or less, the melt fluidity of the resin composition is less likely to decrease.

The average content of component units derived from unsaturated carboxylic acids or derivatives thereof in the olefin polymer (B1) may be determined by measurement or calculated from the composition of the olefin polymer (B1) used in preparing the resin composition.

For example, the average content of component units derived from unsaturated carboxylic acids or derivatives thereof in olefin polymer (B1) can be measured by NMR. The measurement conditions can be the same as those in the examples described below.

The average content of component units derived from unsaturated carboxylic acids or derivatives thereof in the olefin polymer (B1) can be calculated from the following formula (1), where xi (mass %) is the content of component units derived from unsaturated carboxylic acids or the like in the modified or unmodified ethylene-α-olefin copolymer constituting the olefin polymer (B1) (modification amount) and Mi (parts by mass) is the content of the modified or unmodified ethylene-α-olefin copolymer in the olefin polymer (B1) (i is an integer of 2 or more).
Formula (1): Average content (average modification amount) (mass%) = (Σxi * Mi / ΣMi) × 100

For example, when the olefin polymer (B1) contains M1 (parts by mass) of a modified ethylene/α-olefin copolymer (B1-1) (content of component units derived from unsaturated carboxylic acid: x1 (% by mass)) and M2 (parts by mass) of an unmodified ethylene/α-olefin copolymer (B1-2) (content of component units derived from unsaturated carboxylic acid: x2 (% by mass)), the average content of component units derived from unsaturated carboxylic acid in the olefin polymer (B1) (average modification amount) can be calculated as follows: {(x1 * M1 + x2 * M2) / (M1 + M2)} × 100. Note that when the olefin polymer (B1) consists of only one type of modified ethylene/α-olefin copolymer, the average modification amount of the olefin polymer (B1) will be the same as the modification amount of the modified ethylene/α-olefin copolymer (B1-1).

The average content of component units derived from unsaturated carboxylic acids or derivatives thereof in the olefin polymer (B1) can be adjusted by the content of component units derived from unsaturated carboxylic acids or derivatives thereof in the modified ethylene/α-olefin copolymer (B1-1), the content ratio of the modified ethylene/α-olefin copolymer (B1-1) to the unmodified ethylene/α-olefin copolymer (B1-2), etc.

The average density of the olefin polymer (B1) is preferably 0.800 g/ ^cm3 or more and less than 0.890 g/ ^cm3 , more preferably 0.830 g/ ^cm3 or more and less than 0.890 g/ ^cm3 , even more preferably 0.850 g/ ^cm3 or more and less than 0.890 g/ ^cm3 , and most preferably 0.860 g/ ^cm3 or more and less than 0.890 g/ ^cm3 .

The average density of the olefin polymer (B1) is preferably determined by measurement (for example, a method in accordance with JIS K7112:1999). When the olefin polymer (B1) contains two or more types of modified or unmodified ethylene-α-olefin copolymers, the average density may be calculated based on the following formula:

When the density of the modified or unmodified ethylene/α-olefin copolymer constituting the olefin polymer (B1) is di (mass %) and the content of the modified or unmodified ethylene/α-olefin copolymer in the olefin polymer (B1) is Mi (parts by mass) (where i is an integer of 2 or more), it can be calculated from the following formula (2):
Formula (2): Average density (g/cm ³ )=ΣMi/Σ(Mi/di)
(di: density of each polymer, Mi: content of each polymer (parts by mass), i: number of polymer species)

The MFR of the olefin polymer (B1), measured according to ASTM D1238 at 190°C under a load of 2.16 kg, is preferably 0.05 g/10 min or more. An MFR of 0.05 g/10 min or more can further enhance the fluidity of the semi-aromatic polyamide resin composition at high temperatures. There is no particular upper limit for the MFR, but it is preferably 20 g/10 min or less.

1-3. Styrene-based thermoplastic elastomer (B2)
The styrene-based thermoplastic elastomer (B2) is blended into the semi-aromatic polyamide resin composition to improve the tensile elongation at break, tensile strength at break, flexural strength, flexural modulus, fluidity, etc. of the resulting molded article.

Examples of styrene-based thermoplastic elastomers include styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene copolymer (SIS), styrene-ethylene/butylene-styrene copolymer (SEBS), and styrene-ethylene/propylene-styrene copolymer (SEPS). Of these, styrene-ethylene/butylene-styrene copolymer (SEBS) is preferred from the viewpoint of improving fluidity and elongation at break.

From the viewpoint of improving compatibility with the semi-aromatic polyamide resin (A) and the olefin polymer (B1), the styrene-based thermoplastic elastomer (B2) preferably contains a styrene-based thermoplastic elastomer modified with an unsaturated carboxylic acid or its derivative (hereinafter referred to as modified elastomer (B2-1)). The modified elastomer (B2-1) contains component units derived from an unsaturated carboxylic acid or its derivative.

1-3-1. Modified elastomer (B2-1)
The content (modification amount) of component units derived from unsaturated carboxylic acids or derivatives thereof in the modified elastomer (B2-1) may be such that the average content (average modification amount) of component units derived from unsaturated carboxylic acids or derivatives thereof in the styrene-based thermoplastic elastomer (B2) falls within the range described below. For example, the content (modification amount) is preferably 0.05% by mass or more and 5.0% by mass or less, more preferably 0.10% by mass or more and 3.0% by mass or less, more preferably 0.10% by mass or more and 2.0% by mass or less, and particularly preferably 0.30% by mass or more and 2.0% by mass or less, relative to the mass of the modified elastomer (B2-1). When the content (modification amount) is 0.05% by mass or more, the modified elastomer (B2-1) can sufficiently interact with the modified ethylene-α-olefin copolymer (B1-1), thereby improving compatibility. Furthermore, when the content is 5.0% by mass or less, excessive increases in melt viscosity due to excessive interaction are suppressed, and melt fluidity is less likely to decrease. The content (modification amount) can be calculated from the charge ratio when preparing the modified elastomer (B2-1) in the same manner as in the modified ethylene/α-olefin copolymer (B1-1), or can be measured by the NMR method.

The MFR of the modified elastomer (B2-1), measured according to ASTM D1238 at 190°C under a load of 2.16 kg, is preferably 0.1 g/10 min or more and 50 g/10 min or less, and more preferably 0.2 g/10 min or more and 20 g/10 min or less. An MFR of 0.1 g/10 min or more can further enhance the fluidity of the semi-aromatic polyamide resin composition at high temperatures, and an MFR of 50 g/10 min or less can facilitate injection molding of the resulting resin composition.

The modified elastomer (B2-1) is obtained by graft-modifying an unmodified styrene-based thermoplastic elastomer with an unsaturated carboxylic acid or its derivative.

The content of styrene-derived component units in the styrene-based thermoplastic elastomer is preferably 20 mol% or more and 80 mol% or less, and more preferably 30 mol% or more and 65 mol% or less.

(Unsaturated carboxylic acid or its derivative)
The unsaturated carboxylic acid or its derivative is the same as that described above.

(Graft modification)
Graft modification can be carried out by various conventionally known methods. For example, it may be carried out by a melt modification method in which an unmodified styrene-based thermoplastic elastomer is melted using an extruder, and a graft monomer is added to carry out graft copolymerization. From the viewpoint of efficiently graft copolymerizing the graft monomer, it is preferable to carry out the reaction in the presence of a radical initiator. The radical initiator is the same as described above.

1-3-2. Unmodified elastomer (B2-2)
The elastomer (B2) may contain an unmodified elastomer (B2-2). The unmodified elastomer (B2-2) is a styrene-based thermoplastic elastomer that is not modified with an unsaturated carboxylic acid or a derivative thereof. The unmodified elastomer (B2-2) can impart good melt fluidity to the semi-aromatic polyamide resin composition.

The unmodified elastomer (B2-2) can be, for example, a styrene-based thermoplastic elastomer used as a raw material for the modified elastomer (B2-1). That is, the composition and melt flow rate of the unmodified elastomer (B2-2) can be in the same range as the composition and melt flow rate of the styrene-based thermoplastic elastomer used as a raw material for the modified elastomer (B2-1). Note that the unmodified elastomer (B2-2) may be different from the styrene-based thermoplastic elastomer used as a raw material for the modified elastomer (B2-1).

1-3-3. Physical Properties The average content (average modification amount) of component units derived from unsaturated carboxylic acids or their derivatives in the styrene-based thermoplastic elastomer (B2) is preferably 0.05% by mass or more and 5.0% by mass or less, based on the styrene-based thermoplastic elastomer (B2). When the average content (average modification amount) is 0.05% by mass or more, the styrene-based thermoplastic elastomer (B2) can sufficiently interact with the semi-aromatic polyamide resin (A), thereby improving compatibility. Furthermore, when the average content (average modification amount) is 5.0% by mass or less, excessive increases in melt viscosity due to excessive interaction between the styrene-based thermoplastic elastomer (B2) and the semi-aromatic polyamide resin (A) are suppressed, thereby preventing a decrease in melt fluidity and thus preventing a loss of moldability. The average content (average modification amount) can be calculated using formula (1), as described above.

The average content of component units derived from unsaturated carboxylic acids or derivatives thereof in the styrene-based thermoplastic elastomer (B2) can be adjusted by the amount of modification of the modified elastomer (B2-1) and the content ratio of the modified elastomer (B2-1) to the unmodified elastomer (B2-2).

The mass ratio (B1/B2) of the olefin polymer (B1) to the styrene-based thermoplastic elastomer (B2) preferably satisfies 0.01 < B1/B2 < 99. When B1/B2 exceeds 0.01, the molded article can be imparted with appropriate flexibility and can have an increased elongation at break. When B1/B2 is less than 99, the strength of the molded article is less likely to be impaired. From the viewpoint of further increasing the elongation at break, tensile strength at break, and flexural strength of the molded article and further enhancing the fluidity of the semi-aromatic polyamide resin composition, it is more preferable that B1/B2 be 0.05 ≦ B1/B2 ≦ 10, even more preferably that 0.08 ≦ B1/B2 ≦ 8, even more preferably that 0.09 ≦ B1/B2 ≦ 6, particularly preferably that 0.01 ≦ B1/B2 ≦ 3, and most preferably that 0.05 ≦ B1/B2 ≦ 1. In particular, when the content of the styrene-based thermoplastic elastomer (B2) relative to the olefin polymer (B1) is high, it is believed that the interaction between the aromatic rings contained in the styrene-based thermoplastic elastomer (B2) and the aromatic rings of the polyamide is more pronounced, which tends to result in more sufficient increases in fluidity and elongation at break. From this perspective, it is preferable that B1/B2 ≦ 3, and more preferably that B1/B2 ≦ 1.

1-4. Other Components The semi-aromatic polyamide resin composition of the present invention may further contain other components in addition to those described above, provided that the effects of the present invention are not impaired. Examples of such other components include additives such as inorganic fillers, organic fillers, organic flame retardants, lubricants, antioxidants (heat stabilizers), heat stabilizers, weather stabilizers, antistatic agents, antislip agents, antiblocking agents, antifogging agents, pigments, dyes, natural oils, synthetic oils, and waxes. Furthermore, the composition may further contain other heat-resistant resins.

[Inorganic filler (C)]
The inorganic filler (C) may be an inorganic filler having a fibrous, powdery, granular, plate-like, needle-like, cloth-like or mat-like shape.

Examples of fibrous inorganic fillers include glass fiber, carbon fiber, asbestos fiber, and boron fiber. Of these, glass fiber is particularly preferred. The use of glass fiber improves moldability and also improves mechanical properties such as strength (elastic modulus) and heat resistance properties such as heat distortion temperature of molded articles containing the inorganic filler.

The average length of the fibrous inorganic filler is typically 0.1 mm or more and 20 mm or less, and preferably 0.3 mm or more and 6 mm or less. The aspect ratio of the fibrous inorganic filler is typically 10 or more and 2000 or less, and preferably 30 or more and 600 or less.

In addition to fibrous inorganic fillers, other fillers in powder, granule, plate-like, needle-like, cloth-like, or mat-like shapes can also be used. Examples of such other fillers include powder-like or plate-like inorganic compounds such as silica, silica alumina, alumina, calcium carbonate, titanium dioxide, talc, wollastonite, diatomaceous earth, clay, kaolin, spherical glass, mica, gypsum, red iron oxide, magnesium oxide, and zinc oxide, as well as needle-like inorganic compounds such as potassium titanate. Two or more of these fillers can also be used in combination.

The average particle size of other fillers is typically 0.1 μm or more and 200 μm or less, and preferably 1 μm or more and 100 μm or less.

Fiber fillers and other fillers can also be treated with silane coupling agents or titanium coupling agents before use.

The inorganic filler (C) preferably contains at least one of a fibrous filler and another filler, and more preferably contains at least one of a fibrous filler and talc.

[Organic filler]
Examples of the organic filler include wholly aromatic polyamides such as polyparaphenylene terephthalamide, polymetaphenylene terephthalamide, polyparaphenylene isophthalamide, polymetaphenylene isophthalamide, condensates of diaminodiphenyl ether and terephthalic acid (isophthalic acid) and condensates of para(meta)aminobenzoic acid, wholly aromatic polyamideimides such as condensates of diaminodiphenyl ether and trimellitic anhydride or pyromellitic anhydride, wholly aromatic polyesters, wholly aromatic polyimides, heterocycle-containing compounds such as polybenzimidazole and polyimidazophenanthroline, and secondary processed products such as powder, plate, fiber, or cloth formed from polytetrafluoroethylene or the like.

[Organic flame retardants]
The organic flame retardant may be a polybrominated styrene, a brominated polyethylene ether, or a brominated polystyrene, each of which has as its main constituent a component unit produced from a brominated styrene monomer and represented by the following formula [IV]: In the following formula, m is a number of 1 to 5.

The polybrominated styrene preferably contains 60% by weight or more of dibrominated styrene units, and particularly preferably 70% by weight or more. The polybrominated styrene may also be copolymerized with 40% by weight or less, preferably 30% by weight or less, of monobrominated styrene and/or tribrominated styrene in addition to dibrominated styrene.

In addition to the organic flame retardants described above, the semi-aromatic polyamide resin composition of the present invention can also use at least one flame retardant aid selected from antimony oxide, sodium antimonate, tin oxide, iron oxide, zinc oxide, and zinc nitrate. Sodium antimonate is particularly preferred, and substantially anhydrous sodium antimonate that has been heat-treated at a high temperature of 550°C or higher is particularly preferred.

[Lubricant (D)]
The lubricant (D) can further increase the fluidity of the semi-aromatic polyamide resin composition during melt-kneading and reduce mold release resistance.

Higher fatty acids, their metal salts, esters, or amides can be used as lubricants (D).

The higher fatty acid has 8 or more carbon atoms, and preferably has 8 to 40 carbon atoms. The fatty acid is preferably a monocarboxylic acid. Examples of higher fatty acids include saturated fatty acids such as octylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, 12-hydroxystearic acid, behenic acid, montanic acid, and sebacic acid, and unsaturated fatty acids such as erucic acid, oleic acid, and ricinoleic acid. Of these, montanic acid, 12-hydroxystearic acid, and behenic acid are preferred.

Higher fatty acid metal salts are metal salts of the above-mentioned higher fatty acids. Examples of metal elements that form metal salts include Group 1 elements (alkali metals) such as sodium and potassium; Group 2 elements (alkaline earth metals) such as calcium, magnesium, and barium; and Group 3 elements such as zinc and aluminum, with calcium salts, magnesium salts, zinc salts, and aluminum salts being preferred. Examples of such higher fatty acid metal salts include calcium 12-hydroxystearate, zinc 12-hydroxystearate, magnesium 12-hydroxystearate, aluminum 12-hydroxystearate, calcium behenate, zinc behenate, magnesium behenate, sodium montanate, calcium montanate, zinc montanate, magnesium montanate, and aluminum montanate. Of these, metal montanate and metal 12-hydroxystearate are preferred.

Higher fatty acid esters are esters of the above-mentioned higher fatty acids with alcohols (preferably fatty alcohols having 8 to 40 carbon atoms). Examples of fatty alcohols include stearyl alcohol, behenyl alcohol, and lauryl alcohol. Examples of higher fatty acid esters include stearyl stearate and behenyl behenate.

Examples of higher fatty acid amides include stearic acid amide, oleic acid amide, erucic acid amide, ethylene bisstearylamide, ethylene bisoleylamide, N-stearylstearylamide, and N-stearylerucamide.

[Antioxidant (E)]
Examples of the antioxidant (E) include phosphorus-based antioxidants, phenol-based antioxidants, amine-based antioxidants, and sulfur-based antioxidants.

Examples of phosphorus-based antioxidants include 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, triphenyl phosphite, 2-ethylhexyl acid phosphate, dilauryl phosphite, tri-iso-octyl phosphite, tris(2,4-di-tert-butylphenyl) phosphite, trilauryl phosphite, trilauryl-di-thiophosphite, trilauryl-tri-thiophosphite, trisnonylphenyl phosphite, distearyl pentaerythritol diphosphite, tris(mononylphenyl) phosphite, tris(dinonylphenyl) phosphite, trioctadecyl phosphite, 1,1,3-tris(2-methyl-di-tridecylphosphite-5-tert-butylphenyl)butane, 4,4'-butylidene-bis(3-methyl-6-tert-butyl)tridecyl sil phosphite, 4,4'-butylidene-bis(3-methyl-6-tert-butyl-di-tridecyl)phosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol-di-phosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol-di-phosphite, tetrakis(2,4-di-tert-butylphenyl)4,4'-bisphenylene diphosphite, distearyl pentaerythritol diphosphite, tridecyl phosphite, tristearyl phosphite, 2,2'-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite, sorbitol-tris-phosphite-distearyl-mono-C30-diol ester and bis(2,4,6-tri-tert-butylphenyl)pentaerythritol diphosphite. Among these are pentaerythritol-diphosphite-based phosphorus antioxidants such as bis(2,4-di-tert-butylphenyl)pentaerythritol-diphosphite and bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol-diphosphite, as well as tetrakis(2,4-di-tert-butylphenyl)4,4'-bisphenylene diphosphite.

Examples of phenolic antioxidants include 3,9-bis{2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyl]-1,1-dimethylethyl}-2,4,8,10-tetraoxaspiro[5,5]undecane, 2,6-di-tert-butyl-p-cresol, 2,4,6-tri-tert-butylphenol, n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenol)propionate, styrenated phenol, 4-hydroxy-methyl-2,6-di-tert-butyl ethylphenol, 2,5-di-tert-butyl-hydroquinone, cyclohexylphenol, butylhydroxyanisole, 2,2'-methylene-bis-(4-methyl-6-tert-butylphenol), 2,2'-methylene-bis-(4-ethyl-6-tert-butylphenol), 4,4'-iso-propylidenebisphenol, 4,4'-butylidene-bis(3-methyl-6-tert-butylphenol), 1,1-bis-(4-hydroxy-phenyl)cyclohexane, 4,4'-methylene-bis-(2,6-di- tert-butylphenol), 2,6-bis(2'-hydroxy-3'-tert-butyl-5'-methylmethylbenzyl)4-methyl-phenol, 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butyl-phenyl)butane, 1,3,5-tris-methyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxy-benzyl)benzene, tetrakis[methylene-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane, tris(3,5-di-tert -butyl-4-hydroxyphenyl)isocyanurate, tris[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl-oxyethyl]isocyanate, 4,4'-thiobis(3-methyl-6-tert-butylphenol), 2,2'-thiobis(4-methyl-6-tert-butylphenol), 4,4'-thiobis(2-methyl-6-tert-butylphenol), and N,N'-hexamethylenebis(3,5-di-tert-butylphenol-4-hydroxycinnamamide).

Examples of amine antioxidants include 4,4'-bis(α,α-dimethylbenzyl)diphenylamine, phenyl-α-naphthylamine, phenyl-β-naphthylamine, N,N'-diphenyl-p-phenylenediamine, N,N'-di-β-naphthyl-p-phenylenediamine, N-cyclohexyl-N'-phenyl-p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, aldol-α-naphthylamine, 2,2,4-trimethyl-1,2-dihydroquinone polymer, and 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline.

Examples of sulfur-based antioxidants include thiobis(β-naphthol), thiobis(N-phenyl-β-naphthylamine), 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, dodecyl mercaptan, tetramethylthiuram monosulfide, tetramethylthiuram disulfide, nickel dibutyldithiocarbamate, nickel isopropyl xanthate, dilauryl thiodipropionate, and distearyl thiodipropionate.

[Other heat-resistant resins]
Examples of other heat-resistant resins include PPS (polyphenylene sulfide), PPE (polyphenyl ether), PES (polyether sulfone), PEI (polyether imide), LCP (liquid crystal polymer), and modified products of these resins. Polyphenylene sulfide is particularly preferred.

1-5. Composition of Semi-Aromatic Polyamide Resin Composition In the semi-aromatic polyamide resin composition of the present invention, the content of the semi-aromatic polyamide resin (A) is preferably 70% by mass or more and 90% by mass or less, more preferably 70% by mass or more and 85% by mass or less, even more preferably 73% by mass or more and 83% by mass or less, and particularly preferably 73% by mass or more and 80% by mass or less, relative to the total mass of (A), (B1), and (B2). When the content of the semi-aromatic polyamide resin (A) is 70% by mass or more, the strength and heat resistance of the molded article are easily increased, and the fluidity of the polyamide resin composition in high-temperature environments can be further improved. When the content is 90% by mass or less, the strength and heat resistance of the molded article are less likely to be impaired.

In the semi-aromatic polyamide resin composition of the present invention, the content of olefin polymer (B1) can be adjusted as appropriate so as to fall within the range of the total content of olefin polymer (B1) and styrene-based thermoplastic elastomer (B2) described below, but is preferably 1% by mass or more and 25% by mass or less, and more preferably 1% by mass or more and 15% by mass or less, relative to the total mass of (A), (B1), and (B2). When the content of olefin polymer (B1) is 1% by mass or more, the elongation at break of the resulting molded article can be further increased, and when it is 15% by mass or less, the strength of the molded article can be further increased.

In the semi-aromatic polyamide resin composition of the present invention, the content of the styrene-based thermoplastic elastomer (B2) can be adjusted as appropriate so that it falls within the range of the total content of the olefin polymer (B1) and the styrene-based thermoplastic elastomer (B2), as described below. However, it is preferably 1% by mass or more and 30% by mass or less, and more preferably 1% by mass or more and 25% by mass or less, relative to the total mass of (A), (B1), and (B2). When the content of the olefin polymer (B1) is 1% by mass or more, the elongation at break of the resulting molded article can be further increased, and when it is 25% by mass or less, the strength of the molded article can be further increased.

In the semi-aromatic polyamide resin composition of the present invention, the total content of the olefin polymer (B1) and the styrene-based thermoplastic elastomer (B2) is 10% by mass or more and 30% by mass or less, preferably 15% by mass or more and 30% by mass or less, more preferably 17% by mass or more and 27% by mass or less, and even more preferably 20% by mass or more and 27% by mass or less, based on the total mass of (A), (B1), and (B2). When the total content of the olefin polymer (B1) and the styrene-based thermoplastic elastomer (B2) is a certain level or more, the elongation at break of the resulting molded article can be further increased. When the total content of the olefin polymer (B1) and the styrene-based thermoplastic elastomer (B2) is a certain level or less, the strength of the molded article can be further increased. In addition, the melt viscosity of the semi-aromatic polyamide resin composition can be adjusted to a viscosity that is more easily molded, thereby increasing fluidity and facilitating stable molding.

As described above, the semi-aromatic polyamide resin composition of the present invention may further contain an inorganic filler (C), a lubricant (F), and an antioxidant (G).

In the semi-aromatic polyamide resin composition of the present invention, the content of inorganic filler (C) can be from 0% to 200% by mass, preferably from 0.01% to 100% by mass, and more preferably from 1% to 50% by mass, relative to the total mass of (A), (B1), and (B2). A content of inorganic filler (C) of 0.01% by mass or more facilitates increasing the strength of the molded article, while a content of 100% by mass or less prevents impairment of the melt fluidity of the resin composition.

In the semi-aromatic polyamide resin composition of the present invention, the content of lubricant (D) can be 0.01% by mass or more and 1.0% by mass or less, preferably 0.05% by mass or more and 0.5% by mass or less, and more preferably 0.06% by mass or more and 0.4% by mass or less, relative to the total mass of (A), (B1), and (B2). A content of lubricant (F) of 0.06% by mass or more can further enhance the fluidity of the semi-aromatic polyamide resin composition during melt-kneading, and a content of 0.4% by mass or less can prevent the mechanical strength of the resulting molded article from being impaired and prevent poor appearance due to bleed-out.

In the semi-aromatic polyamide resin composition of the present invention, the content of antioxidant (E) can be from 0% to 2% by mass, preferably from 0.1% to 5% by mass, and more preferably from 0.1% to 1.0% by mass, based on the total mass of (A), (B1), and (B2). When the content of antioxidant (E) is 0.1% by mass or more, thermal degradation of the molded product is more easily suppressed, and when it is 5% by mass or less, discoloration is less likely to occur.

1-6. Method for Producing Semi-Aromatic Polyamide Resin Composition The semi-aromatic polyamide resin composition of the present invention can be produced by any method. For example, the semi-aromatic polyamide resin composition of the present invention can be produced through the steps of preparing an olefin polymer (B1) and a styrene-based thermoplastic elastomer (B2), melt-kneading the prepared olefin polymer (B1) and styrene-based thermoplastic elastomer (B2) with the semi-aromatic polyamide resin (A), and, if necessary, granulating or pulverizing the mixture.

Furthermore, prior to the melt-kneading step, a step of mixing at least the semi-aromatic polyamide resin (A), the olefin polymer (B1), and the styrene-based thermoplastic elastomer (B2) may be carried out. The mixing method may be, for example, a Henschel mixer, a V blender, a ribbon blender, or a tumbler blender.

2. Molded Article The molded article of the present invention is obtained by molding the semi-aromatic polyamide resin composition of the present invention.

In other words, the semi-aromatic polyamide resin composition prepared as described above can be used to produce molded articles of the desired shape by conventional melt molding methods, such as compression molding, injection molding, or extrusion molding.

For example, the semi-aromatic polyamide resin composition of the present invention can be placed in a molten state in an injection molding machine whose cylinder temperature is adjusted to a temperature equal to or higher than the melting point of the semi-aromatic polyamide resin (A), for example, approximately 300°C to 350°C, and then introduced into a mold of a predetermined shape to produce a molded article.

The shape of the molded article produced using the semi-aromatic polyamide resin composition of the present invention is not particularly limited, and various shapes can be used depending on the application.

The polyamide resin composition of the present invention is also suitable as a resin for forming various molded articles, preferably automotive interior/exterior parts, engine room interior parts, and automotive electrical parts. Examples of molded articles obtained from the semi-aromatic polyamide resin composition of the present invention include automotive exterior parts such as radiator grilles, rear spoilers, wheel covers, hubcaps, cowl vent grilles, air outlet louvers, air scoops, hood bulges, fenders, and tailgates; automotive engine room parts such as cylinder head covers, engine mounts, air intake manifolds, throttle bodies, air intake pipes, radiator tanks, radiator supports, water pump housings such as water pump inlets and water pump outlets, water jacket spacers, thermostat housings such as thermostat housings, cooling fans, fan shrouds, oil pans, oil filter housings, oil filler caps, oil level gauges, timing belts, timing belt covers, and engine covers; and automotive engine room parts such as fuel caps, fuel filler tubes, automotive fuel tanks, fuel sensors, etc. These include automotive fuel system parts such as fuel delivery modules, fuel cut-off valves, quick connectors, canisters, fuel delivery pipes, and fuel filler necks; automotive drive system parts such as shift lever housings and propeller shafts; automotive chassis parts such as stabilizer bar linkage rods; automotive functional parts such as window regulators, door locks, door handles, outside door mirror stays, accelerator pedals, pedal modules, seal rings, bearings, bearing retainers, gears, and actuators; automotive electronic parts such as wire harness connectors, relay blocks, sensor housings, encapsulations, ignition coils, and distributor caps; general-purpose equipment fuel system parts such as fuel tanks for general-purpose equipment (such as brush cutters, lawn mowers, and chainsaws); as well as electrical and electronic parts such as connectors and LED reflectors, building materials, various housings, and exterior parts.

Molded articles made from the semi-aromatic polyamide resin composition of the present invention have good strength and elongation at break. Therefore, they are suitable for automotive fuel tanks, quick connectors, bearing retainers, fuel tanks for general-purpose equipment, fuel caps, fuel filler necks, fuel sender modules, wheel caps, fenders or back doors, various housings, exterior parts, and the like. Examples of various housings and exterior parts include small housings, exterior molded products, and mobile phone housings, and they are particularly suitable for use as mobile phone housings. The semi-aromatic polyamide resin composition of the present invention is also preferably used as a resin for manufacturing connectors that interconnect electronic circuits.

The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to the descriptions in the examples.

1. Constituent Materials 1-1. Semi-aromatic polyamide resin (A)
<Preparation of Semi-Aromatic Polyamide (PA-1)>
2,800 g (24.1 mol) of 1,6-diaminohexane, 2,184 g (13.2 mol) of terephthalic acid, 1,572 g (10.8 mol) of adipic acid, 5.67 g (5.4 × ¹⁰ mol) of sodium hypophosphite monohydrate as a catalyst, 36.5 g (0.30 mol) of benzoic acid as a molecular weight modifier, and 409 ml of ion-exchanged water were placed in an autoclave with a capacity 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 raised to 3.02 MPa. After continuing the reaction for 1 hour, the low-order condensate was discharged into the atmosphere from a spray nozzle installed at the bottom of the autoclave and extracted. Thereafter, the low-order condensate was cooled to room temperature, pulverized in a pulverizer to a particle size of 1.5 mm or less, and dried at 110 ° C for 24 hours. The resulting low-order condensate had a water content of 3,000 ppm and an intrinsic viscosity [η] of 0.15 dl/g, yielding 5,440 g of a polyamide precursor.

The polyamide precursor was then dried and melt-polymerized using a twin-screw extruder at a cylinder temperature of 330°C to obtain a semi-aromatic polyamide (PA-1).

The composition of the resulting semi-aromatic polyamide (PA-1) was such that, among the dicarboxylic acid-derived component units, the content of terephthalic acid-derived component units was 55 mol %, the content of adipic acid-derived component units was 45 mol %, and among the diamine-derived component units, the content of 1,6-diaminohexane-derived component units was 100 mol %. Furthermore, the semi-aromatic polyamide (PA-1) had an intrinsic viscosity [η] of 1.0 dl/g and a melting point Tm of 310°C.

1-2. Other polyamide resins (A')
<Polyamide (PA-2)>
Nylon 6 (Amilan CM1017, manufactured by Toray Industries, Inc.) was used. The melting point Tm of polyamide (PA-2) was 225°C.

The intrinsic viscosity [η] of semi-aromatic polyamide (PA-1) was measured using the following method.

[Intrinsic viscosity [η]]
The intrinsic viscosity [η] of the resulting semi-aromatic polyamide resin was measured as follows: 0.5 g of the semi-aromatic polyamide resin was dissolved in 50 ml of a 96.5% sulfuric acid solution. The flow time of the resulting solution at 25°C ± 0.05°C was measured using an Ubbelohde viscometer, and the intrinsic viscosity [η] was calculated based on the formula: [η] = η/(C(1 + 0.205η)).
[η]: Intrinsic viscosity (dl/g)
ηSP: specific viscosity C: sample concentration (g/dl)
t: number of seconds for the sample solution to flow down (seconds)
t ₀ : Number of seconds (seconds) for blank sulfuric acid to flow
ηSP=(t−t ₀ )/t ₀

The melting points Tm of semi-aromatic polyamide (PA-1) and polyamide (PA-2) were measured using the following method.

[Melting point Tm]
The melting points Tm of the semi-aromatic polyamide (PA-1) and polyamide (PA-2) were measured using a differential scanning calorimeter (DSC220C, manufactured by Seiko Instruments Inc.) as follows.

Approximately 5 mg of semi-aromatic polyamide (PA-1) or polyamide (PA-2) was sealed in a measuring aluminum pan and heated from room temperature to 350°C at 10°C/min. To completely melt the resin, it was held at 350°C for 3 minutes and then cooled to 30°C at 10°C/min. After leaving it at 30°C for 5 minutes, it was heated a second time to 350°C at 10°C/min. The temperature (°C) of the endothermic peak during this second heating was taken as the melting point (Tm) of the polyamide.

1-2. Olefin polymer (B1)
(Polymer (B1-1))
<Preparation of Modified Ethylene/1-Butene Copolymer (PO-1-1)>
An ethylene-1-butene copolymer (PO-2-1) was prepared using a Ti-based catalyst.
The ethylene/1-butene copolymer (PO-2-1) had an ethylene content of 81 mol %, a density of 0.861 g/cm ³ , and an MFR (ASTM D 1238, 190°C, 2.16 kg load) of 0.5 g/10 min.

100 parts by mass of the ethylene-1-butene copolymer (PO-2-1) prepared above, 1.2 parts by mass of maleic anhydride, and 0.06 parts by mass of peroxide (Perhexyne-25B, manufactured by NOF Corporation) were mixed in a Henschel mixer, and the resulting mixture was melt-graft-modified in a 65 mmφ single-screw extruder set to 230°C to obtain a modified ethylene-1-butene copolymer (PO-1-1).

<Preparation of Modified Ethylene/1-Butene Copolymer (PO-1-2)>
An ethylene-1-butene copolymer (PO-2-2) was prepared using a Ti-based catalyst.
The ethylene/1-butene copolymer (PO-2-2) had an ethylene content of 85 mol %, a density of 0.870 g/cm ³ , and an MFR (ASTM D 1238, 190°C, 2.16 kg load) of 0.6 g/10 min.

100 parts by mass of the ethylene/1-butene copolymer (PO-2-2) prepared above, 1.2 parts by mass of maleic anhydride, and 0.06 parts by mass of peroxide (Perhexyne-25B, manufactured by NOF Corporation) were mixed in a Henschel mixer, and the resulting mixture was melt-graft-modified in a 65 mmφ single-screw extruder set to 230°C to obtain a modified ethylene/1-butene copolymer (PO1-2).

1-3. Styrene-based thermoplastic elastomer (B2)
<Modified styrene-ethylene/butylene-styrene copolymer (B2)>
A modified styrene-ethylene/butylene-styrene copolymer (Tuftec M1913, manufactured by Asahi Kasei Corporation) was used.

The compositions and physical properties of the olefin polymer (B1) and the styrene-based thermoplastic elastomer (B2) are shown in Table 1.

The modification amount, density, and MFR of each copolymer were measured using the following methods.

[Amount of modification]
The content (modification amount) (mass %) of component units derived from maleic anhydride in each copolymer was measured by NMR under the following conditions.
Measurement device: Nuclear magnetic resonance device (ECP500 type, manufactured by JEOL Ltd.)
Observed nucleus: ^13C (125MHz)
Sequence: Single pulse proton decoupling
Pulse width: 4.7 μsec (45° pulse)
Repeat time: 5.5 seconds
Accumulation count: 10,000 times or more
Solvent: orthodichlorobenzene/deuterated benzene (volume ratio: 80/20) mixed solvent
Sample concentration: 55 mg/0.6 mL
Measurement temperature: 120℃
Reference value of chemical shift: 27.50 ppm

[density]
The density was measured at a temperature of 23°C using a density gradient tube in accordance with JIS K7112:1999.

[MFR]
The MFR was measured in accordance with ASTM D1238 at 190°C under a load of 2.16 kg.

1-4. Other Components <Inorganic Filler (C)>
Talc (average particle size 1.6 μm)

<Sliding material (D)>
Sodium montanate

<Antioxidant (E)>
phenolic antioxidants

2. Preparation of Semi-Aromatic Polyamide Resin Compositions (Examples 1 to 5 and Comparative Examples 1 to 11)
Semi-aromatic polyamide resin (A), olefin polymer (B1), styrene-based thermoplastic elastomer (B2), inorganic filler (C), lubricant (D), and antioxidant (E) were mixed in a tumbler blender to obtain the compositions shown in Tables 2 to 4, and then melt-kneaded at a cylinder temperature of 310°C using a 30 mmφ vented twin-screw extruder. The kneaded mixture was then extruded into strands and cooled in a water tank. The strands were then taken up in a pelletizer and cut to obtain pellets of semi-aromatic polyamide resin compositions.

The tensile strength and elongation at break, flexural strength and flexural modulus, and injection flowability of the resulting semi-aromatic polyamide resin composition were evaluated using the following methods.

[Tensile strength at break, tensile elongation at break]
The obtained polyamide resin composition was molded using the following injection molding machine under the following molding conditions to obtain an ASTM dumbbell-shaped test piece Type I having a thickness of 3.2 mm.
(Molding conditions)
Molding machine: Toshiba Machine Co., Ltd. EC75N-2A
Cylinder temperature: 320°C (Examples 1 to 5, Comparative Examples 1 to 4), 250°C (Comparative Examples 5 to 11)
Mold temperature: 50°C
Injection setting speed: 100mm/sec
The obtained test piece was left for 24 hours in a nitrogen atmosphere at a temperature of 23° C. Then, a tensile test was carried out in an atmosphere at a temperature of 23° C. and a relative humidity of 50%, and the tensile strength at break (MPa) and the tensile elongation at break (%) were measured.

[Flexural strength, flexural modulus]
The obtained semi-aromatic polyamide resin composition was injection molded under the following molding conditions to prepare a test piece having a length of 127 mm, a width of 12.7 mm and a thickness of 3.2 mm.
Molding machine: Toshiba Machine Co., Ltd. EC75N-2A
Cylinder temperature: 320°C (Examples 1 to 5, Comparative Examples 1 to 4), 250°C (Comparative Examples 5 to 11)
Mold temperature: 50°C
The obtained test piece was left for 24 hours in a nitrogen atmosphere at a temperature of 23° C. Then, a bending test was carried out in an atmosphere of a temperature of 23° C. and a relative humidity of 50% using a bending tester (NTESCO AB5) with a span of 51 mm and a bending speed of 5 mm/min, to measure the bending strength (MPa) and bending modulus (MPa).

[Flow length test (injection flowability)]
Using a bar flow mold having a width of 10 mm and a thickness of 0.5 mm, injection was carried out under the following conditions, and the flow length (mm) of the resin in the mold was measured.
Injection molding machine: Sodick Plustec Co., Ltd., Tupearl TR40S3A
Injection pressure setting: 2000 kg/ ^cm2
Cylinder set temperature: 320°C (Examples 1 to 5, Comparative Examples 1 to 4), 250°C (Comparative Examples 5 to 11)
Mold temperature: 50°C

The evaluation results for Examples 1 to 5 are shown in Table 2, the evaluation results for Comparative Examples 1 to 4 are shown in Table 3, and the evaluation results for Comparative Examples 5 to 11 are shown in Table 4.

As shown in Table 2, Examples 1 to 5, which contained semi-aromatic polyamide (A), olefin polymer (B1), and styrene-based thermoplastic elastomer (B2), and in which the combined content of olefin polymer (B1) and styrene-based thermoplastic elastomer (B2) was 10 to 30 parts by mass per 100 parts by mass of the combined total of (A), (B1), and (B2), all exhibited high tensile elongation at break and fluidity. It is believed that blending olefin polymer (B1) and styrene-based thermoplastic elastomer (B2) formed a structure in which a phase of styrene-based thermoplastic elastomer (B2) was dispersed within a phase of olefin polymer (B1), or formed a structure in which a phase of olefin polymer (B1) was dispersed within a phase of styrene-based thermoplastic elastomer (B2), significantly improving tensile elongation at break and fluidity.

In particular, Examples 3 to 5, in which the ratio of the styrene-based thermoplastic elastomer (B2) content to the olefin polymer (B1) content was high, were found to have higher breaking elongation and fluidity.

In contrast, as shown in Tables 3 and 4, Comparative Examples 1 to 11, which contained only either the olefin polymer (B1) or the styrene-based thermoplastic elastomer (B2), were unable to increase both the tensile elongation at break and the fluidity. In particular, Comparative Examples 5 to 11, which did not contain the semi-aromatic polyamide (A), were able to increase the elongation at break, but the fluidity was significantly reduced, and even when the olefin polymer (B1) and the styrene-based thermoplastic elastomer were used, the fluidity was not improved (Comparative Example 11).

Molded articles made from the semi-aromatic polyamide resin composition of the present invention have good strength, elongation at break, and fluidity at high temperatures. Therefore, it is expected that this will broaden the applicability of semi-aromatic polyamide resin compositions to various housings, exterior components, and other applications, and contribute to the further spread of semi-aromatic polyamide resin compositions.

Claims (11)

a semi-aromatic polyamide resin (A) having a melting point measured by a differential scanning calorimeter (DSC) of 280°C or higher and 330°C or lower;
an olefin polymer (B1);
a styrene-based thermoplastic elastomer (B2);
A semi-aromatic polyamide resin composition comprising:
The semi-aromatic polyamide resin (A) contains a component unit derived from a dicarboxylic acid and a component unit derived from a diamine,
the component units derived from the dicarboxylic acid contain component units derived from terephthalic acid in an amount of 45 mol% or more relative to the total number of moles of the component units derived from the dicarboxylic acid,
the diamine-derived component units include, relative to the total number of moles of the diamine-derived component units, component units derived from linear alkylenediamines having from 4 to 18 carbon atoms, which account for from 50 mol % to 100 mol %; and component units derived from branched alkylenediamines having from 4 to 18 carbon atoms, which account for from 0 mol % to 50 mol %;
The olefin polymer (B1) is
It contains a modified ethylene/α-olefin copolymer (B1-1) modified with an unsaturated carboxylic acid or a derivative thereof,
the average content of the component units derived from the unsaturated carboxylic acid or a derivative thereof in the olefin polymer (B1) is 0.01% by mass or more and 5.0% by mass or less;
the total content of the olefin polymer (B1) and the styrene-based thermoplastic elastomer (B2) is 10% by mass or more and 30% by mass or less based on the total mass of the semi-aromatic polyamide resin (A), the olefin polymer (B1), and the styrene-based thermoplastic elastomer (B2);
Semi-aromatic polyamide resin composition. The semi-aromatic polyamide resin composition according to claim 1, wherein the styrene-based thermoplastic elastomer (B2) is a styrene-based thermoplastic elastomer selected from the group consisting of styrene-butadiene-styrene copolymer (SBS), styrene-isoprene-styrene copolymer (SIS), styrene-ethylene/butylene-styrene copolymer (SEBS), and styrene-ethylene/propylene-styrene copolymer (SEPS). The semi-aromatic polyamide resin composition according to claim 1 or 2, wherein the mass ratio (B1/B2) of the olefin polymer (B1) to the styrene-based thermoplastic elastomer (B2) satisfies 0.01 < B1/B2 < 99. The semi-aromatic polyamide resin composition according to any one of claims 1 to 3, wherein the content of component units derived from the unsaturated carboxylic acid or its derivative in the modified ethylene-α-olefin copolymer (B1-1) is 0.05% by mass or more and 5.0% by mass or less. The styrene-based thermoplastic elastomer (B2) includes a modified elastomer (B2-1) modified with an unsaturated carboxylic acid or a derivative thereof,
The semi-aromatic polyamide resin composition according to any one of claims 1 to 4, wherein the average content of component units derived from the unsaturated carboxylic acid or a derivative thereof in the styrene-based thermoplastic elastomer (B2) is 0.05 mass% or more and 5.0 mass% or less. The semi-aromatic polyamide resin composition according to any one of claims 1 to 5, wherein the density of the modified ethylene/α-olefin copolymer (B1-1) is 0.800 g/ ^cm3 or more and less than 0.890 g/ ^cm3 . The semi-aromatic polyamide resin composition according to any one of claims 1 to 6, wherein the mass ratio (B1/B2) of the olefin polymer (B1) to the styrene-based thermoplastic elastomer (B2) satisfies 0.08 < B1/B2 < 8.0. The component unit derived from the diamine is
the component units derived from the linear alkylenediamine having from 4 to 18 carbon atoms account for from 85 mol% to 100 mol% of the total number of moles of the component units derived from the diamine, and the component units derived from the branched alkylenediamine having from 4 to 18 carbon atoms account for from 0 mol% to 15 mol% of the total number of moles of the component units derived from the diamine,
The semi-aromatic polyamide resin composition according to any one of claims 1 to 7. The linear alkylenediamine having 4 to 18 carbon atoms is 1,6-diaminohexane.
The semi-aromatic polyamide resin composition according to any one of claims 1 to 8. Further containing an inorganic filler (C),
The semi-aromatic polyamide resin composition according to any one of claims 1 to 9. A molded product obtained by molding the semi-aromatic polyamide resin composition according to any one of claims 1 to 10.
Molded body.