Polyarylene sulfide resin composition, insert molded article, and method for improving heat shock resistance of polyarylene sulfide resin composition

Abstract

Provided are a polyarylene sulfide resin composition having excellent heat shock resistance, an insert molded article, and a method for improving the heat shock resistance of the polyarylene sulfide resin composition. This polyarylene sulfide resin composition contains a polyarylene sulfide resin and a lubricant. The content of the lubricant is 0.5 parts by mass or more and 5.5 parts by mass or less based on 100 parts by mass of the polyarylene sulfide resin. The lubricant has a melting point or a softening point of 40 to 130°C.

Description

Polyarylene sulfide resin composition, insert molded article, and method for improving the heat shock resistance of polyarylene sulfide resin composition.

[0001] This disclosure relates to a polyarylene sulfide resin composition, an insert molded article, and a method for improving the heat shock resistance of a polyarylene sulfide resin composition.

[0002] Polyarylene sulfide resins (hereinafter sometimes referred to as "PAS resins"), exemplified by polyphenylene sulfide resin (hereinafter sometimes referred to as "PPS resin"), are widely used in electrical and electronic equipment components, automotive parts, and chemical equipment components due to their excellent heat resistance, mechanical properties, chemical resistance, dimensional stability, and flame retardancy. Insert molded products are molded products in which an insert member made of metal or the like and a resin member made of a thermoplastic resin composition are integrally molded. Because the thermal expansion and contraction rates due to temperature changes differ greatly between the metal or the like and the thermoplastic resin composition that constitute the insert molded product, the insert molded product may break due to temperature changes during use. In particular, when the insert molded product is used as a part around an automobile engine, excellent heat shock resistance is required. PAS resin alone is known to be brittle and lacks toughness, so when it is integrally molded with an insert member made of metal or inorganic solid material, for example, it is known to have poor durability when alternately exposed to high and low temperatures, so-called heat shock resistance (high and low temperature impact resistance). As an example of a technique to improve heat shock resistance, it is known that an elastomer is added to the PAS resin or a PAS resin with high toughness is used. Adding a soft elastomer to the PAS resin improves impact resistance and heat shock resistance, but because the elastomer is soft and has poor thermal stability, problems such as a decrease in strength and an increase in mold deposits occur. Also, if a PAS resin with high toughness and high molecular weight is used, the fluidity of the resin decreases, and the molding temperature must be raised to a higher temperature in order to mold accurately, which increases mold deposits. Patent document 1 describes a polyarylene sulfide resin composition in which a copolymer is blended with a polyarylene sulfide resin, and by using a PAS resin with high viscosity (high molecular weight), a polyarylene sulfide resin composition can maintain heat shock resistance and fluidity even with a small amount of copolymer added.

[0003] International Publication No. 2017 / 110807

[0004] The object of this disclosure is to provide a polyarylene sulfide resin composition, an insert molded article, and a method for improving the heat shock resistance of a polyarylene sulfide resin composition, which have excellent heat shock resistance.

[0005] This disclosure includes the following embodiments: a polyarylene sulfide resin composition comprising a polyarylene sulfide resin and a lubricant, wherein the content of the lubricant is 0.5 parts by mass or more and 5.5 parts by mass or less per 100 parts by mass of the polyarylene sulfide resin, and the melting point or softening point of the lubricant is 40 to 130°C.

[0006] This disclosure provides a polyarylene sulfide resin composition with excellent heat shock resistance, an insert molded article, and a method for improving the heat shock resistance of a polyarylene sulfide resin composition.

[0007] A schematic diagram of an insert molded product used to evaluate heat shock resistance, where (a) is a perspective view and (b) is a plan view. A diagram showing the insert member shown in Figure 1, where (a) is a perspective view and (b) is an enlarged plan view of the acute-angled portion. An explanatory diagram of the dimensions (unit: mm) of the insert molded product shown in Figure 1, where (a) is a plan view and (b) is a side view. A schematic diagram of the molded body manufactured in the evaluation of the amount of mold deposits in the embodiment (top: top view, bottom: side view).

[0008] One embodiment of the present disclosure will be described in detail below, but the scope of the present disclosure is not limited to the embodiment described herein, and various modifications can be made without departing from the spirit of the present disclosure. Each embodiment disclosed herein can be combined with any other features disclosed herein. If multiple upper and lower limits are given for a particular parameter, any combination of these upper and lower limits can be used to create a suitable numerical range. The lower and / or upper limits of the numerical ranges described herein may be replaced with numerical values ​​within that range, as shown in the examples. The expression "X to Y" indicating a numerical range means "X or greater and Y or less". Each numerical parameter is given as a value rounded to one digit below the given significant figures. If a particular description given for one embodiment also applies to other embodiments, that description may be omitted in the other embodiments.

[0009] [Polyarylene sulfide resin composition] The first embodiment of this disclosure relates to a polyarylene sulfide resin composition. The polyarylene sulfide resin composition according to this embodiment comprises a polyarylene sulfide resin and a lubricant, wherein the content of the lubricant is 0.5 parts by mass or more and 5.5 parts by mass or less per 100 parts by mass of the polyarylene sulfide resin, and the melting point or softening point of the lubricant is 40 to 130°C.

[0010] Conventionally, lubricants have been widely used to improve the fluidity of resin compositions and their release properties during molding. For such purposes, lubricants are used in small amounts, typically 0.3% by mass or less, in the resin composition. In the course of research, the inventors found that increasing the lubricant content can sometimes improve heat shock resistance. Further research by the inventors revealed, surprisingly, that when a lubricant having a specific range of melting or softening points is blended with a polyarylene sulfide resin in a certain proportion or higher, the heat shock resistance of the resin composition improves, leading to the completion of this disclosure. Furthermore, the resin composition of this disclosure allows for a reduction in the amount of elastomers or high molecular weight polyarylene sulfide resins that have been conventionally used to improve heat shock resistance, or eliminates the need for their blending altogether. Therefore, it is possible to reduce adverse effects such as a decrease in strength and an increase in mold deposits that can occur when adding elastomers or using high molecular weight polyarylene sulfide resins.

[0011] (Polyarylene sulfide (PAS) resin) Polyarylene sulfide resin (hereinafter also referred to as "PAS resin") is a resin having repeating units represented by the following general formula (I): -(Ar-S)- ... (I) (where Ar represents an arylene group.)

[0012] The arylene group is not particularly limited, but examples include p-phenylene group, m-phenylene group, o-phenylene group, substituted phenylene group, p,p'-diphenylene sulfone group, p,p'-biphenylene group, p,p'-diphenylene ether group, p,p'-diphenylene carbonyl group, naphthalene group, etc. The PAS resin can be a homopolymer using the same repeating unit as represented by the above general formula (I), or a copolymer containing different types of repeating units.

[0013] As a homopolymer, one having a p-phenylene group as the arylene group and consisting of repeating p-phenylene sulfide groups is preferred. This is because homopolymers with repeating p-phenylene sulfide groups have extremely high heat resistance and exhibit high strength and rigidity over a wide temperature range. By using such a homopolymer, a molded article with excellent physical properties can be obtained.

[0014] As the copolymer, a combination of two or more different arylene sulfide groups from among the arylene groups containing the above-mentioned arylene group can be used. Among these, a combination containing a p-phenylene sulfide group and an m-phenylene sulfide group is preferred from the viewpoint of obtaining a molded article with high physical properties such as heat resistance, moldability, and mechanical properties. A polymer containing 70 mol% or more of p-phenylene sulfide groups is more preferred, and a polymer containing 80 mol% or more is even more preferred. Note that the PAS resin having phenylene sulfide groups is a PPS resin.

[0015] PAS resins are generally known to have molecular structures that are substantially linear with no branching or crosslinking, or structures that have branching or crosslinking, depending on their manufacturing method. In this embodiment, both types are effective. Among them, high molecular weight polymers with a substantially linear structure obtained by condensation polymerization from monomers mainly composed of bifunctional halogen aromatic compounds are particularly preferred. In this embodiment, the PAS resin used may be a mixture of two or more PAS resins with different molecular weights.

[0016] The melt viscosity of the PAS resin is not particularly limited as long as it does not impair the effects of this disclosure, but at 310°C and a shear rate of 1200 sec －１ The melt viscosity measured is preferably 600 Pa·s or less, including in the case of the above-mentioned mixed system, and among those in the range of 5 to 500 Pa·s, is particularly preferred because it has an excellent balance of mechanical properties and fluidity.

[0017] In one embodiment, the melt viscosity of the PAS resin is set to 310°C and a shear rate of 1200 sec, from the viewpoint of excellent moldability. －１The melt viscosity measured is preferably 7 to 300 Pa·s, more preferably 10 to 250 Pa·s, and even more preferably 13 to 200 Pa·s.

[0018] The method for producing PAS resin is not particularly limited and can be produced by conventionally known production methods. When obtaining high molecular weight PAS resin, for example, it can be produced by synthesizing a low molecular weight PAS resin and then polymerizing it at high temperature in the presence of a known polymerization aid to increase its molecular weight.

[0019] In one embodiment, the PAS resin content in the PAS resin composition can be 10 to 99.95% by mass, 15 to 90% by mass, or 15 to 85% by mass, but is not limited thereto. In one embodiment, it is preferable that 80% or more by mass of the thermoplastic resin contained in the PAS resin composition is PAS resin, and it is more preferable that 90% or more by mass is PAS resin. In one embodiment, the thermoplastic resin contained in the PAS resin composition may consist solely of PAS resin.

[0020] (Lubricant) The polyarylene sulfide resin composition according to this embodiment contains a lubricant. In this embodiment, the lubricant has a melting or softening point of 40 to 130°C, and its content is 0.5 parts by mass or more and 5.5 parts by mass or less per 100 parts by mass of PAS resin. By including the above lubricant in the above content in the polyarylene sulfide resin composition, the heat shock resistance of the insert molded product is improved. The following reasons are considered to be the non-limiting mechanism by which such a unique effect occurs. That is, when an insert molded product is used in an environment with a large range of temperature changes, the insert portion is prone to strain due to the temperature change, and as a result, the insert portion is prone to cracking. A lubricant having a melting or softening point within the above range changes state from a solid state to a melted or softened state in an environment with a large range of temperature changes, and is therefore considered to have the effect of mitigating the strain of the molded product due to temperature changes. By setting the lubricant content to a predetermined amount, this effect is easily manifested, and the heat shock resistance is improved. In contrast, lubricants with a melting or softening point below 40°C or above 130°C do not undergo changes in state due to temperature changes in the temperature range expected in environments where insert molded products are used, such as the engine compartment of an automobile, and therefore do not effectively reduce strain in the molded product. In this disclosure, "lubricant" refers to an additive commonly used to improve mold release properties during resin molding, or to improve moldability by increasing the fluidity of the resin. Lubricants can improve mold release properties by reducing friction between the resin and the processing machine during resin molding, and can improve fluidity by reducing friction between resin particles. Lubricants that reduce friction between resin particles are called "internal lubricants," and lubricants that reduce friction between the resin and the metal surface of the molding machine are called "external lubricants."

[0021] In one embodiment, from the viewpoint of easily obtaining the effect of improving heat shock resistance, it is preferable that the lubricant includes an internal lubricant. Examples of the internal lubricant include paraffin wax, polyolefin wax such as polyethylene lubricant; ester wax such as fatty acid ester lubricant; and montanic acid wax. These may be used alone or in combination of two or more. In one embodiment, from the viewpoint of easily obtaining the effect of improving heat shock resistance, it is preferable that the internal lubricant includes one or more selected from pentaerythritol stearate ester and polyethylene wax.

[0022] In one embodiment, the melting or softening point of the lubricant is preferably 50 to 110°C, more preferably 55 to 110°C, even more preferably 60 to 110°C, even more preferably 60 to 105°C, and particularly preferably 60 to 100°C. Having the melting or softening point of the lubricant within this range makes it easier to improve heat shock resistance. The melting or softening point of the lubricant may be the manufacturer's catalog value, or it may be a value measured using a differential scanning calorimeter by the DSC method (method described in JIS K7121) under a nitrogen atmosphere and a heating rate of 10°C / min.

[0023] In one embodiment, the lubricant content is preferably 0.5 parts by mass or more and 2 parts by mass or less, more preferably 0.6 parts by mass or more and 2 parts by mass or less, even more preferably 0.7 parts by mass or more and 1.9 parts by mass or less, and particularly preferably 0.8 parts by mass or more and 1.8 parts by mass or less, per 100 parts by mass of polyarylene sulfide resin. When the lubricant content is within the above range, the heat shock resistance is more easily improved.

[0024] (Inorganic Filler) In one embodiment, the PAS resin composition preferably further contains an inorganic filler from the viewpoint of improving mechanical strength. Examples of inorganic fillers include fibrous inorganic fillers, plate-shaped inorganic fillers, and powder-shaped inorganic fillers. Examples of fibrous inorganic fillers include glass fibers, silica fibers, silica-alumina fibers, zirconia fibers, boron nitride fibers, silicon nitride fibers, boron fibers, potassium titanate fibers, wollastonite, etc., with glass fibers being the most preferred. From the viewpoint of further improving mechanical properties, the average fiber diameter of the fibrous inorganic filler is preferably 9 μm to 17 μm, and more preferably 9 μm to 15 μm. The average fiber length of the fibrous inorganic filler is not particularly limited, but considering the mechanical properties and moldability of the molded article, the average fiber length (cut length) in the initial shape is preferably 0.01 to 3.5 mm, more preferably 0.05 to 3.5 mm, even more preferably 0.1 to 3.5 mm, and particularly preferably 0.5 to 3 mm. Fibrous inorganic fillers can also use hollow fibers for purposes such as reducing the specific gravity of the resin composition. The "average fiber diameter" is calculated by measuring the longest straight-line distance in the cross-section of 10 fiber pieces using a scanning electron microscope and image processing software, and taking the arithmetic mean. The average fiber diameter can also be the manufacturer's value (a value published by the manufacturer in their catalog, etc.). The "average fiber length" is calculated by measuring the length of 1000 fiber pieces using a scanning electron microscope and image processing software, and taking the arithmetic mean. The average fiber length can also be the manufacturer's value (a value published by the manufacturer in their catalog, etc.).

[0025] Examples of plate-shaped inorganic fillers include glass flakes, mica, kaolin, clay, and alumina (plate-shaped). The average particle size (volume-based cumulative 50% diameter D50) of the plate-shaped inorganic filler is preferably 10 μm to 1000 μm, and more preferably 30 μm to 800 μm, in its initial form (form before melting and kneading). The average particle size (volume-based cumulative 50% diameter D50) can be measured by laser diffraction scattering.

[0026] Examples of granular inorganic fillers include silica, quartz powder, glass beads, glass powder, silicates such as calcium silicate, aluminum silicate, and diatomaceous earth, metal oxides such as iron oxide, titanium oxide, zinc oxide, and alumina (granular), metal carbonates such as calcium carbonate and magnesium carbonate, metal sulfates such as calcium sulfate and barium sulfate, and others such as silicon carbide, silicon nitride, and boron nitride.

[0027] The average particle size (volume-based cumulative 50% diameter D50) of the granular inorganic filler is preferably 0.1 μm to 50 μm, and more preferably 1 μm to 40 μm, in its initial form (form before melting and kneading). The average particle size (volume-based cumulative 50% diameter D50) can be measured by laser diffraction scattering. The inorganic filler may contain one or more selected from the various inorganic fillers described above.

[0028] The inorganic filler may or may not be surface-treated. From the viewpoint of further improving heat shock resistance, it is preferable that the inorganic filler be surface-treated. If it is surface-treated, it may be surface-treated with various surface treatment agents such as epoxy compounds, isocyanate compounds, silane compounds, titanate compounds, and fatty acids, which are generally known. For example, in the case of glass fibers, surface treatment can improve adhesion with PAS resin. The surface treatment agent may be applied to the inorganic filler in advance to perform surface treatment or convergence treatment before material preparation, or it may be added at the same time as material preparation. In one embodiment, it is preferable that the inorganic filler includes a fibrous inorganic filler from the viewpoint of further improving heat shock resistance. In one embodiment, the inorganic filler may include a plate-shaped inorganic filler and / or a granular inorganic filler. In one embodiment, it is preferable that the inorganic filler further includes a plate-shaped inorganic filler and / or a granular inorganic filler in addition to the fibrous inorganic filler. In another embodiment, it is more preferable that the inorganic filler consists only of a fibrous inorganic filler.

[0029] In one embodiment, the fibrous inorganic filler preferably contains glass fibers from the viewpoint of further improving heat shock resistance.

[0030] From the viewpoint of further improving heat resistance and mechanical strength, the inorganic filler content is preferably 5 to 250 parts by mass, more preferably 10 to 200 parts by mass, and even more preferably 20 to 150 parts by mass, per 100 parts by mass of PAS resin.

[0031] (Alkoxysilane Compounds) In one embodiment, the PAS resin composition preferably further contains alkoxysilane compounds. Further inclusion of alkoxysilane compounds can increase the strength of the molded article. The alkoxysilane compounds preferably contain one or more alkoxysilane compounds having one or more selected from epoxy groups, amino groups, vinyl groups, (meth)acrylic groups, isocyanate groups, and mercapto groups.

[0032] In one embodiment, the alkoxysilane compound is preferably represented by the following formula (II): R １ ｎ Si ( OR ２ ) ４－ｎ ... (II) In equation (II), R １ R is an alkyl group having 1 to 18 carbon atoms (preferably 1 to 10) and possessing an epoxy group, an amino group, a vinyl group, a (meth)acrylic group, an isocyanate group, or a mercapto group. ２ n is an alkyl group having 1 to 4 carbon atoms, and n is an integer from 1 to 3.

[0033] Examples of alkoxysilane compounds include epoxyalkoxysilanes, aminoalkoxysilanes, vinylalkoxysilanes, (meth)acrylalkoxysilanes, isocyanatealkoxysilanes, and mercaptoalkoxysilanes, and it is preferable to include one or more of these. The number of carbon atoms in the alkoxy group is preferably 1 to 10, and particularly preferably 1 to 4.

[0034] Examples of epoxyalkoxysilanes include γ-glycidoxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and γ-glycidoxypropyltriethoxysilane.

[0035] Examples of aminoalkoxysilanes include γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-diallylaminopropyltrimethoxysilane, and γ-diallylaminopropyltriethoxysilane.

[0036] Examples of vinylalkoxysilanes include vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltris(β-methoxyethoxy)silane.

[0037] Examples of (meth)acrylalkoxysilanes include γ-acryloxypropyltriethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, and γ-methacryloxypropylmethyldiethoxysilane.

[0038] Examples of isocyanatealkoxysilanes include γ-isocyanatopropyltriethoxysilane and γ-isocyanatopropyltrimethoxysilane.

[0039] Examples of mercaptoalkoxysilanes include γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane.

[0040] Among these, epoxyalkoxysilanes and aminoalkoxysilanes are more preferred, and γ-aminopropyltriethoxysilane is particularly preferred.

[0041] In one embodiment, the content of the alkoxysilane compound is 0.1 to 10 parts by mass, preferably 0.3 to 10 parts by mass, more preferably 0.5 to 10 parts by mass, relative to 100 parts by mass of the PAS resin. When the content of the alkoxysilane compound is 0.1 to 10 parts by mass relative to 100 parts by mass of the PAS resin, burrs during molding can be reduced.

[0042] In one embodiment, the content of the alkoxysilane compound may be 0.1 to 5.0 parts by mass, may be 0.3 to 3.0 parts by mass, or may be 0.5 to 1.0 parts by mass, relative to 100 parts by mass of the polyarylene sulfide resin.

[0043] In one embodiment, the content of the alkoxysilane compound may be 0.05 to 1.0% by mass, or may be 0.1 to 0.9% by mass, relative to 100 parts by mass of the PAS resin composition, but is not limited thereto.

[0044] (Other Additives) The PAS resin composition may optionally contain known substances generally added to thermoplastic resins, for example, flame retardants, colorants such as dyes and pigments, stabilizers such as antioxidants and ultraviolet absorbers, crystallization accelerators, crystal nucleating agents, and the like.

[0045] The PAS resin composition may contain an elastomer to further improve heat shock resistance. Examples of the elastomer include olefin copolymers. From the viewpoint of preventing the occurrence of mold deposit during molding, the content of the elastomer is preferably less than 35 parts by mass, more preferably 0.01 to 20 parts by mass, still more preferably 0.1 to 15 parts by mass, particularly preferably 0.1 to 10 parts by mass, relative to 100 parts by mass of the polyarylene sulfide resin. The PAS resin composition can improve the heat shock resistance of a molded article even without containing an elastomer. In one embodiment, the PAS resin composition may not contain an elastomer. Since the PAS resin composition does not contain an elastomer or can have a reduced content of the elastomer, adverse effects such as a decrease in strength of the resin composition and an increase in mold deposit are less likely to occur.

[0046] The PAS resin composition may optionally contain other thermoplastic resins other than PAS resin, as long as they do not impair the effects of the present invention. Examples of other thermoplastic resins include polyethersulfone resins and polysulfone resins. Two or more of these thermoplastic resins can also be used in mixture form. The content of other thermoplastic resin components can be, for example, 20% by mass or less, 15% by mass or less, or 10% by mass or less of the total resin composition constituting the resin molded article.

[0047] (Heat shock resistance test specimen) In one embodiment, in a test in which a heat shock resistance test specimen is cooled at -40°C for 1.5 hours and then heated at 180°C for 1.5 hours, the PAS resin composition is preferably 135 or more, more preferably 140 or more, even more preferably 145 or more, and particularly preferably 150 or more, until a crack occurs. The "heat shock resistance test specimen" is an insert molded body for evaluating heat shock resistance and has the following characteristics. The heat shock resistance test specimen has an insert member and a resin member that covers a part of the insert member. The insert member is columnar, and the shape of its top and bottom surfaces is teardrop-shaped, with one side being an arc shape and the other side being an acute angle shape. The resin member is formed using the PAS resin composition described above. The resin member has a thick portion and a thin portion, and the acute-angled portion of the insert member is positioned toward the thin portion of the resin member. In one embodiment, the heat shock resistance test specimen has a columnar insert member and a resin member that surrounds at least a portion of the columnar insert member around its entire circumference. At least a portion of the cross-section of the columnar insert member perpendicular to the height direction is formed into an acute angle shape with a radius of curvature of 0.2 mm at the tip, and the resin member has a thickness of 1 mm at the portion where the acute-angled tip of the insert member makes contact. Figures 1 to 3 show schematic diagrams of the heat shock resistance test specimen. Figure 1 shows an insert-molded heat shock resistance test specimen 1, Figure 2 shows an insert member 11, and Figure 3 shows the dimensions of the heat shock resistance test specimen 1. As shown in Figure 1, the heat shock resistance test specimen 1 is molded in such a state that a portion of the metal insert member 11 is embedded in the height direction of a cylindrical resin member 10 containing a PAS resin composition. The cylindrical resin member 10 is molded using a PAS resin composition. As shown in Figure 2, the insert member 11 is columnar, and its top and bottom surfaces have a teardrop shape, with one side being an arc shape and the other an acute angle shape. As shown in the enlarged view of Figure 2(b), the tip of the acute angle portion is arc-shaped, and its radius of curvature R is 0.2 mm.The insert member 11 is higher than the height of the cylindrical resin member 10, and a part thereof protrudes (see FIG. 1(a)). Further, as shown in FIG. 3(a), the center O of a circle having the arc of the insert member 11 as a part thereof. １ and the center O of the circle of the resin member 10 ２ do not coincide with each other, and the insert member 11 is arranged such that the acute-angle shaped side thereof is close to the side surface of the resin member 10. The distance d between the tip of the acute-angle shape of the insert member 11 and the side surface of the resin member 10 ｗ is 1 mm. In the resin member 10, the vicinity of the tip of the acute-angle shape of the insert member 11 forms a stress concentration portion and is the region having the smallest wall thickness. Note that numerical values of the dimensions of the test piece are shown in FIG. 3, and the unit thereof is mm. In the resin member 10 of the test piece 1, a trace of a resin injection port (gate mark) is formed on the side surface opposite to the side surface closest to the acute-angle shape of the insert member 11. In this case, in the resin member 10, a weld portion is formed on the side surface closest to the acute-angle shape of the insert member 11. An insert-molded article having such a shape has a weld portion formed in a thin-walled portion of the resin member, so that heat shock resistance tends to be easily lowered.

[0048] (Manufacturing Method) The method for manufacturing the PAS resin composition according to the present embodiment is not limited, and can be carried out by equipment and methods generally used for preparing synthetic resin compositions. Generally, necessary components are mixed, and melt-kneaded using a single-screw or twin-screw extruder. Thereafter, the mixture can be extruded to obtain molding pellets.

[0049] (Uses) The PAS resin composition according to the present embodiment can be widely used as materials for electrical and electronic equipment parts, materials for automobile parts, materials for chemical equipment parts, and the like. In particular, since the PAS resin composition according to the present embodiment is excellent in heat shock resistance, it can be preferably used for insert molding (for manufacturing insert-molded articles).

[0050] [Insert Molded Article] The second embodiment of this disclosure relates to an insert molded article. The insert molded article according to this embodiment has a resin member containing the above-described PAS resin composition and an insert member. In one embodiment, the insert molded article is integrally molded by insert molding, with the resin member containing the above-described PAS resin composition and the insert member. The PAS resin composition is as described above and is therefore omitted from this description.

[0051] The insert member preferably contains a metal, alloy, or inorganic solid. The metal, alloy, or inorganic solid constituting the insert member is not particularly limited, but it is preferable that it does not deform or melt when in contact with the resin composition during molding. Examples include metals such as aluminum, magnesium, copper, and iron, alloys of the above metals such as brass, and inorganic solids such as glass and ceramics. The shape and size of the insert molded product are not particularly limited and can be shaped according to the application.

[0052] The method for manufacturing insert molded articles is not limited and they can be manufactured by general injection molding. For example, an insert molded article can be obtained by placing an insert member made of metal or an inorganic solid in a mold and injecting a molten PAS resin composition into the mold.

[0053] [Method for improving the heat shock resistance of a polyarylene sulfide resin composition] A third embodiment of this disclosure relates to a method for improving the heat shock resistance of a polyarylene sulfide resin composition. The method for improving the heat shock resistance of a polyarylene sulfide resin composition according to this embodiment includes adding a lubricant in an amount of 0.5 parts by mass or more and 5.5 parts by mass or less per 100 parts by mass of the polyarylene sulfide resin to a resin composition containing a polyarylene sulfide resin, wherein the melting point or softening point of the lubricant is 40 to 130°C.

[0054] The type, content, and other physical properties of "heat shock resistance," "PAS resin composition," and "lubricant" are as described in the first embodiment above. The amount of PAS resin and lubricant added is the same as the amount of PAS resin and lubricant included in the PAS resin composition described above. Other details regarding the PAS resin composition and lubricant described in the first embodiment also apply to this embodiment.

[0055] In one embodiment, a method for improving the heat shock resistance of a polyarylene sulfide resin composition is a method in which, in a test in which the above-mentioned heat shock resistance test piece is cooled at -40°C for 1.5 hours and then heated at 180°C for 1.5 hours, the number of cycles until cracks occur is preferably 135 or more, more preferably 140 or more, even more preferably 145 or more, and particularly preferably 150 or more.

[0056] [Polyarylene sulfide resin composition containing a heat shock resistance enhancer] The fourth embodiment of this disclosure relates to a polyarylene sulfide resin composition containing a heat shock resistance enhancer. The polyarylene sulfide resin composition according to this embodiment comprises a polyarylene sulfide resin and a heat shock resistance enhancer comprising one or more selected from pentaerythritol stearate ester and polyethylene-based wax, wherein the content of the heat shock resistance enhancer is 0.5 parts by mass or more and 5.5 parts by mass or less per 100 parts by mass of the polyarylene sulfide resin. The polyarylene sulfide resin is as described in the first embodiment above.

[0057] (Heat shock resistance improver) The heat shock resistance improver contains one or more selected from pentaerythritol stearate and polyethylene-based wax. Pentaerythritol stearate and polyethylene-based wax have conventionally been used as lubricants (especially internal lubricants). Pentaerythritol stearate and polyethylene-based wax typically have a melting or softening point of 40 to 130°C, and by using a predetermined amount, the heat shock resistance of the insert molded product can be further improved.

[0058] In this context, "heat shock resistance enhancer" refers to an agent that improves the heat shock resistance of an insert molded product compared to a polyarylene sulfide resin composition that does not contain pentaerythritol stearate and polyethylene-based wax. In the first embodiment described above, the heat shock resistance of the resin composition is improved by incorporating a lubricant having a melting or softening point of 40 to 130°C. In this embodiment, the effect of further improving heat shock resistance by including one or more selected from pentaerythritol stearate and polyethylene-based wax as lubricants is utilized, and the agent is used as a heat shock resistance enhancer.

[0059] In one embodiment, the heat shock resistance enhancer may consist of only one or more selected from pentaerythritol stearate and polyethylene-based waxes.

[0060] The content of the heat shock resistance improver is 0.5 parts by mass or more and 5.5 parts by mass or less per 100 parts by mass of polyarylene sulfide resin, preferably 0.5 parts by mass or more and 2 parts by mass or less, more preferably 0.6 parts by mass or more and 2 parts by mass or less, even more preferably 0.7 parts by mass or more and 1.9 parts by mass or less, and particularly preferably 0.8 parts by mass or more and 1.8 parts by mass or less. When the content of the heat shock resistance improver is within the above range, heat shock resistance is more easily improved. Regarding the content described herein, the numerical values ​​are:

[0061] The resin composition according to this embodiment may contain inorganic fillers, alkoxysilane compounds, thermoplastic resins other than PAS resin, and other additives, similar to the resin composition in the first embodiment, and the types and content thereof are the same as in the first embodiment.

[0062] A non-limiting list of exemplary embodiments and combinations of exemplary embodiments of the present disclosure is disclosed below: [1] A polyarylene sulfide resin composition comprising a polyarylene sulfide resin and a lubricant, wherein the content of the lubricant is 0.5 parts by mass or more and 5.5 parts by mass or less per 100 parts by mass of the polyarylene sulfide resin, and the melting point or softening point of the lubricant is 40 to 130°C. [2] The polyarylene sulfide resin composition according to [1], wherein the melting point or softening point of the lubricant is 50 to 110°C. [3] The polyarylene sulfide resin composition according to [1] or [2], wherein the content of the lubricant is 0.5 parts by mass or more and 2 parts by mass or less per 100 parts by mass of the polyarylene sulfide resin. [4] The polyarylene sulfide resin composition according to any one of [1] to [3], wherein the lubricant comprises an internal lubricant. [5] The polyarylene sulfide resin composition according to any one of [1] to [4], wherein the lubricant comprises one or more selected from pentaerythritol stearate ester and polyethylene-based wax. [6] The polyarylene sulfide resin composition according to any one of [1] to [5], further comprising an inorganic filler. [7] The polyarylene sulfide resin composition according to any one of [1] to [6], comprising an inorganic filler in an amount of 5 to 250 parts by mass per 100 parts by mass of the polyarylene sulfide resin. [8] The polyarylene sulfide resin composition according to any one of [1] to [7], comprising a fibrous inorganic filler. [9] The polyarylene sulfide resin composition according to any one of [1] to [8], comprising glass fibers.

[10] The polyarylene sulfide resin composition according to any one of [1] to [9], further comprising an alkoxysilane compound.

[11] A polyarylene sulfide resin composition according to any one of [1] to

[10] , wherein in a test in which a heat shock resistance test specimen is cooled at -40°C for 1.5 hours and then heated at 180°C for 1.5 hours, the number of cycles until a crack occurs is 135 or more (provided that the heat shock resistance test specimen has a columnar insert member and a resin member surrounding at least a part of the columnar insert member around its entire circumference, the columnar insert member has at least a part of its cross section perpendicular to the height direction formed into an acute angle shape with a radius of curvature of 0.2 mm at the tip, and the resin member has a thickness of 1 mm at the part where the tip of the acute angle shape of the insert member is in contact.

[12] A polyarylene sulfide resin composition according to any one of [1] to

[11] for insert molding.

[13] A polyarylene sulfide resin composition comprising a polyarylene sulfide resin and a heat shock resistance improver comprising one or more selected from pentaerythritol stearate ester and polyethylene-based wax, wherein the content of the heat shock resistance improver is 0.5 parts by mass or more and 5.5 parts by mass or less per 100 parts by mass of the polyarylene sulfide resin.

[14] An insert molded article having a resin member comprising the polyarylene sulfide resin composition according to any one of [1] to

[13] and an insert member.

[15] A method for improving the heat shock resistance of a polyarylene sulfide resin composition, comprising adding a lubricant in an amount of 0.5 parts by mass or more and 5.5 parts by mass or less per 100 parts by mass of the polyarylene sulfide resin to a resin composition comprising the polyarylene sulfide resin, wherein the melting point or softening point of the lubricant is 40 to 130°C.

[0063] Each configuration and its combination in each embodiment is an example, and additions, omissions, substitutions, and other modifications can be made as appropriate without departing from the spirit of this disclosure. This disclosure is not limited by the embodiments.

[0064] The present disclosure will be further illustrated by the following examples, but these examples will not limit the interpretation of the present disclosure.

[0065] [Each Raw Material Component] The details of each raw material component used in the examples and comparative examples are as follows.

[0066] ・PPS-1: PPS resin, manufactured by Kureha Corporation, "Fortron KPS", melt viscosity 130 Pa·s ・PPS-2: PPS resin, manufactured by Kureha Corporation, "Fortron KPS", melt viscosity 30 Pa·s ・Lubricant-1: manufactured by NOF Corporation, pentaerythritol stearate ester, "Unistar H476", melting point 63℃ ・Lubricant-2: manufactured by Sanyo Chemical Industries, Ltd., polyethylene resin, "Sunwax 161-P", melting point 103℃ ・Lubricant-3: manufactured by ADEKA Corporation, pyromellitic acid ester, "ADEKA Sizer UL-100", melting point 25℃ or less (liquid at 25℃) ・Lubricant-4: manufactured by Kao Corporation, ethylenebis-stearate amide, "KAOWAX EB-G", melting point 144℃ - Silane compound: γ-aminopropyltriethoxysilane, "KBE-903P", manufactured by Shin-Etsu Chemical Co., Ltd. - Glass fiber: Chopped strand, ECS03T-717, manufactured by Nippon Electric Glass Co., Ltd., average fiber diameter 13 μm, average fiber length 3 mm

[0067] (Measurement of Melt Viscosity of PPS Resin) The melt viscosity of each of the above PPS resins, as well as the melt viscosity of the mixed resin of PPS-1 (50 parts by mass) and PPS-2 (50 parts by mass), were measured as follows: Using a capillary graph manufactured by Toyo Seiki Seisakusho, a flat die with a diameter of 1 mm and a length of 20 mm was used as the capillary, with a barrel temperature of 310°C and a shear rate of 1200 sec. －１ The melt viscosity was measured.

[0068] (Measurement of the melting point of the lubricants) The melting point (Tm) of each of the above lubricants was measured using a DSC device (Differential Scanning Calorimeter, DSC-Q1000, manufactured by TA INSTRUMENT Inc.) by the DSC method (method described in JIS K7121) under a nitrogen atmosphere and a heating rate of 10°C / min.

[0069] [Examples 1-4, Comparative Examples 1-5] The above PPS resin and lubricant were dry-blended in the compositions and proportions shown in Table 1 to obtain a mixture which was then fed into a twin-screw extruder at a cylinder temperature of 320°C. Glass fibers were also fed into the extruder from a side feeder and melt-kneaded to obtain PAS resin composition pellets.

[0070] (Evaluation of heat shock resistance (HS resistance)) Using each PAS resin composition and a metal insert member, test pieces shown in Figures 1 to 3 were insert-molded by injection molding, and their heat shock resistance (HS resistance) was evaluated. The explanation of Figures 1 to 3 is as described above.

[0071] The above test specimens were subjected to a thermal shock test using an ESPEC Corporation machine. The cycle of cooling at -40°C for 1.5 hours followed by heating at 180°C for 1.5 hours was repeated, and the weld area was observed every 20 cycles. The number of cycles at which cracks occurred in the weld area was evaluated as an indicator of thermal shock resistance. A higher number of cycles indicates superior thermal shock resistance. The results are shown in Table 1.

[0072] (Evaluation of Mold Adhesion Amount) Using each PAS resin composition and a mold with a detachable vent and cavity section, the molded body shown in Figure 4 was continuously molded for 4 hours (1000 times) in an injection molding machine under the following conditions. The weight of the vent section removed from the mold was measured before and after continuous molding. The change in weight of the vent section before and after continuous molding was calculated as the amount of mold adhesion to the vent section. ・Injection molding machine: FANUC ROBOSHOT S2000I30A ・Cylinder temperature: 340℃ ・Injection time: 2 seconds ・Cooling time: 10 seconds ・Mold temperature: 140℃ The results are shown in Table 1. Note that "-" in Table 1 means that the component is not included or that the evaluation was not performed.

[0073]

[0074] As shown in Table 1, the PAS resin composition of the example exhibited superior heat shock resistance compared to the PAS resin composition of the comparative example. In other words, the PAS resin composition of the example can provide an insert molded product with excellent heat shock resistance. Furthermore, as shown by the comparison between Example 1 and Example 3, even when the amount of lubricant added was approximately doubled, the amount of mold deposits during molding remained unchanged. In other words, even with a high amount of lubricant added, the PAS resin composition of the example makes it easier to maintain good gas discharge during molding over a long period of time, and as a result, burning of the molded product and deterioration of the mold are less likely to occur.

[0075] The polyarylene sulfide resin composition of this embodiment has excellent heat shock resistance and can therefore be suitably used in the manufacture of various insert molded products, thus possessing industrial applicability. The insert molded product of this embodiment has excellent heat shock resistance and can therefore be suitably used as various insert molded products, thus possessing industrial applicability. The method for improving the heat shock resistance of the polyarylene sulfide resin composition of this embodiment yields a polyarylene sulfide resin composition with excellent heat shock resistance and therefore possesses industrial applicability.

[0076] 1 Heat shock resistance test piece 10 Resin component 11 Insert component

Claims

1. A polyarylene sulfide resin composition comprising a polyarylene sulfide resin and a lubricant, wherein the content of the lubricant is 0.5 parts by mass or more and 5.5 parts by mass or less per 100 parts by mass of the polyarylene sulfide resin, and the melting point or softening point of the lubricant is 40 to 130°C.

2. The polyarylene sulfide resin composition according to claim 1, wherein the lubricant has a melting point or softening point of 50 to 110°C.

3. The polyarylene sulfide resin composition according to claim 1 or 2, wherein the content of the lubricant is 0.5 parts by mass or more and 2 parts by mass or less per 100 parts by mass of the polyarylene sulfide resin.

4. The polyarylene sulfide resin composition according to claim 1 or 2, wherein the lubricant comprises an internal lubricant.

5. The polyarylene sulfide resin composition according to claim 1 or 2, wherein the lubricant comprises one or more selected from pentaerythritol stearate ester and polyethylene-based waxes.

6. The polyarylene sulfide resin composition according to claim 1 or 2, further comprising an inorganic filler.

7. The polyarylene sulfide resin composition according to claim 1 or 2, comprising 5 to 250 parts by mass of an inorganic filler per 100 parts by mass of the polyarylene sulfide resin.

8. A polyarylene sulfide resin composition according to claim 1 or 2, comprising a fibrous inorganic filler.

9. The polyarylene sulfide resin composition according to claim 1 or 2, comprising glass fibers.

10. The polyarylene sulfide resin composition according to claim 1 or 2, further comprising an alkoxysilane compound.

11. In a test in which a heat shock resistance test specimen is cooled at -40°C for 1.5 hours and then heated at 180°C for 1.5 hours, the number of cycles until a crack occurs is 135 or more (provided that the heat shock resistance test specimen comprises a columnar insert member and a resin member surrounding at least a portion of the columnar insert member around its entire circumference, wherein at least a portion of the cross-section of the columnar insert member perpendicular to the height direction is formed into an acute angle shape with a radius of curvature of 0.2 mm at the tip, and the resin member has a thickness of 1 mm at the portion where the tip of the acute angle shape of the insert member is in contact). The polyarylene sulfide resin composition according to claim 1 or 2.

12. The polyarylene sulfide resin composition according to claim 1 or 2, for use in insert molding.

13. A polyarylene sulfide resin composition comprising a polyarylene sulfide resin and a heat shock resistance enhancer comprising one or more selected from pentaerythritol stearate ester and polyethylene-based wax, wherein the content of the heat shock resistance enhancer is 0.5 parts by mass or more and 5.5 parts by mass or less per 100 parts by mass of the polyarylene sulfide resin.

14. An insert molded article having a resin member containing the polyarylene sulfide resin composition according to claim 1 or 13, and an insert member.

15. A method for improving the heat shock resistance of a polyarylene sulfide resin composition, comprising adding a lubricant in an amount of 0.5 parts by mass or more and 5.5 parts by mass or less per 100 parts by mass of the polyarylene sulfide resin to a resin composition containing the polyarylene sulfide resin, wherein the melting point or softening point of the lubricant is 40 to 130°C.

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