Resin compositions, pellets, and molded articles

Abstract

To provide resin compositions, pellets, and molded articles that exhibit excellent sliding properties and mechanical properties, even without containing alkali metal carbonates and / or alkaline earth metal carbonates. [Solution] The resin composition according to this disclosure comprises (A) 100 parts by mass of polyamide resin, (B) 15 parts by mass or more and less than 42 parts by mass of glass fiber, (C) 4.1 to 30.0 parts by mass of polyolefin having an acid value of 2.0 mgKOH / g or less as measured in accordance with JIS K0070 and a weight-average molecular weight of 1000 to 20000, and (D) a melt volume rate (MVR) of 0.5 to 20.5 cm² as measured in accordance with ISO 1133 at 210°C and a load of 5 kgf. 3 The solution is / 10 min and contains 0.1 to 5.1 parts by mass of a polyolefin having polar groups (excluding those that fall under (C) polyolefin), and the content of alkali metal carbonates and / or alkaline earth metal carbonates is less than 2 parts by mass per 100 parts by mass of (A) polyamide resin.

Description

[Technical Field]

[0001] The present invention relates to resin compositions, pellets, molded articles, and methods for producing resin compositions. In particular, it relates to resin compositions mainly composed of polyamide resin. [Background technology]

[0002] The use of polyamide resins in sliding parts has been considered for some time. For example, Patent Document 1 discloses a polyamide resin composition comprising (A) a polyamide resin and (B) a polyolefin wax, wherein the (A) polyamide resin comprises (a-1) 10 to 90% by mass of a semi-aromatic polyamide resin and (a-2) 10 to 90% by mass of an aliphatic polyamide resin having a lower melting point and a glass transition temperature 20°C or more lower than the (a-1) semi-aromatic polyamide resin. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2017-171880 [Overview of the project] [Problems that the invention aims to solve]

[0004] In resin compositions exhibiting excellent sliding properties as described above, it is conceivable to incorporate calcium carbonate to further improve sliding properties. However, incorporating calcium carbonate can sometimes lead to calcium carbonate salts acting as fracture initiation points in molded products, resulting in inferior mechanical properties. The present invention aims to solve these problems and to provide a resin composition, pellets, and molded articles that have excellent sliding properties and mechanical properties, even without containing alkali metal carbonates and / or alkaline earth metal carbonates. [Means for solving the problem]

[0005] Under the above-mentioned problems, the inventors conducted research and found that by blending a polyolefin with no acidic groups and a relatively small molecular weight with a polyolefin having polar groups and a melt volume rate (MVR) within a predetermined range into a polyamide resin, and by adjusting the amount of glass fiber blended, it is possible to obtain a molded product with excellent mechanical properties and sliding properties even without containing alkali metal carbonates and / or alkaline earth metal carbonates, thus solving the above-mentioned problems. Specifically, the above problem was solved by the following means. [1] (A) Per 100 parts by mass of polyamide resin, (B) Glass fiber 15 parts by mass or more and less than 42 parts by mass, (C)4.1 to 30.0 parts by mass of polyolefin having an acid value of 2.0 mgKOH / g or less as measured according to JIS K0070 and a weight-average molecular weight of 1000 to 20000, (D) In ​​accordance with ISO 1133, the melt volume rate (MVR) measured under conditions of 210°C and a load of 5 kgf was 0.5 to 20.5 cm³. 3 It is / 10 min and contains 0.1 to 5.1 parts by mass of a polyolefin having a polar group (excluding those that fall under (C) polyolefin), A resin composition in which the content of alkali metal carbonates and / or alkaline earth metal carbonates is less than 2 parts by mass per 100 parts by mass of (A) polyamide resin. [2] The resin composition according to [1], wherein the content of the inorganic filler other than (B) glass fibers is less than 2 parts by mass per 100 parts by mass of (A) polyamide resin. [3] The resin composition according to [1] or [2], wherein the (A) polyamide resin comprises a semi-aromatic polyamide resin. [4] The average cross-sectional area of ​​the glass fibers (B) is 15 to 100 μm² 2 The resin composition described in any one of [1] to [3]. [5] The resin composition according to any one of [1] to [4], wherein the (D) polyolefin comprises a maleic anhydride-modified polyolefin. [6] The content of the inorganic filler excluding the (B) glass fiber is less than 2 parts by mass with respect to 100 parts by mass of the (A) polyamide resin. The (A) polyamide resin includes a semi-aromatic polyamide resin. The average cross-sectional area of the (B) glass fiber is 40 to 100 μm². 2 and The resin composition according to any one of [1] to [5], wherein the (D) polyolefin includes a maleic anhydride-modified polyolefin. [7] Pellets of the resin composition according to any one of [1] to [6]. [8] A molded article formed from the resin composition according to any one of [1] to [6].

Advantages of the Invention

[0006] According to the present invention, it has become possible to provide a resin composition excellent in slidability and mechanical properties, as well as pellets and molded articles, even without containing a carbonate of an alkali metal and / or a carbonate of an alkaline earth metal.

Embodiments for Carrying Out the Invention

[0007] Hereinafter, embodiments for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail. The following present embodiment is an exemplification for explaining the present invention, and the present invention is not limited only to the present embodiment. In this specification, "~" is used in the sense of including the numerical values described before and after it as lower and upper limits. "A~B" means A or more and B or less. Also, any combination of the upper limit value and the lower limit value of the numerical values in this specification can be cited as an example of the present embodiment.

[0008] In this specification, various physical property values and characteristic values are those at 23°C unless otherwise specified.

[0009] In this specification, the weight average molecular weight and the number average molecular weight are values measured by the following method unless otherwise specified. Weight-average molecular weight (Mw) and number-average molecular weight (Mn) were measured using high-temperature gel permeation chromatography (GPC), and calibration curves were created using standard polystyrene. The molecular weight was then determined by substituting polyethylene for standard polystyrene. The polyolefin used for measurement was added to o-dichlorobenzene, an eluent heated to 140°C, and melted. The molten sample was then filtered to remove insoluble components. Next, the dissolved sample was packed into a 140°C column using a high-temperature GPC (gel permeation chromatography) apparatus, and molecular weight measurement was performed.

[0010] In this specification, unless otherwise specified, the melting point (Tm) and glass transition temperature (Tg) shall be values ​​measured by differential scanning calorimetry (DSC) in accordance with ISO 11357. Specifically, a differential scanning calorimeter is used. The resin is placed in the measurement pan of the differential scanning calorimeter, heated to a temperature above the melting point at a heating rate of 10°C / min under a nitrogen atmosphere, and then rapidly cooled before measurement. The measurement conditions involve heating at a heating rate of 10°C / min, holding at 350°C for 5 minutes, and then cooling at a cooling rate of -10°C / min down to 30°C to determine the glass transition temperature (Tg) and melting point (Tm). The differential scanning calorimeter used is the "DSC-7020" manufactured by Hitachi High-Tech Science Co., Ltd.

[0011] The resin composition of this embodiment consists of (A) 100 parts by mass of polyamide resin, (B) 15 to less than 42 parts by mass of glass fiber, (C) 4.1 to 30.0 parts by mass of polyolefin having an acid value of 2.0 mgKOH / g or less as measured according to JIS K0070 and a weight-average molecular weight of 1000 to 20000, and (D) a melt volume rate (MVR) of 0.5 to 20.5 cm² as measured in accordance with ISO 1133 at 210°C and a load of 5 kgf. 3 The solution is / 10 min and contains 0.1 to 5.1 parts by mass of a polyolefin having polar groups (excluding those corresponding to (C) polyolefin), and is characterized in that the content of alkali metal carbonates and / or alkaline earth metal carbonates is less than 2 parts by mass per 100 parts by mass of (A) polyamide resin. By adopting this configuration, a resin composition with excellent sliding properties and mechanical properties can be obtained even without containing alkali metal carbonates and / or alkaline earth metal carbonates. (A) By blending a polyamide resin with an alkali metal carbonate and / or an alkaline earth metal carbonate and (C) a polyolefin having an acid value of 2.0 mgKOH / g or less as measured according to JIS K0070 and a weight-average molecular weight of 1000 to 20000, the sliding properties can be improved. However, if the amount of alkali metal carbonate and / or alkaline earth metal carbonate is high, these metal carbonates can become the starting point for fracture in the molded product. Therefore, in this embodiment, alkali metal carbonates and / or alkaline earth metal carbonates are either not included, or the amount included is less than 2 parts by mass per 100 parts by mass of (A) polyamide resin, and the amount of glass fiber is reduced to the minimum amount that can maintain mechanical properties. However, it was presumed that (A) polyamide resin and (C) polyolefin are not compatible and tend to have inferior mechanical properties. In this embodiment, in order to make (A) polyamide resin and (C) polyolefin compatible, (D) the melt volume rate (MVR) measured at 210°C and a load of 5 kgf in accordance with ISO 1133 was set to 0.5 to 20.5 cm 3 The process involved a 10-minute interval and the incorporation of a polyolefin having polar groups. As a result, it is presumed that the (A) polyamide resin and (C) olefin component were sufficiently compatible, resulting in a resin composition with excellent sliding properties and superior flexural strength.

[0012] The embodiments of the present invention will be described in detail below, but the description of the constituent elements described below is merely one example of an embodiment of the present invention and is not limited to these.

[0013] <(A) Polyamide resin> The resin composition of this embodiment includes a polyamide resin. The polyamide resin used in this embodiment is not of any particular type and may be an aliphatic polyamide resin or a semi-aromatic polyamide resin, but a semi-aromatic polyamide resin is more preferable.

[0014] Examples of aliphatic polyamide resins include polyamide 4, polyamide 46, polyamide 6, polyamide 66, polyamide 666, polyamide 610, polyamide 11, and polyamide 12, with polyamide 6, polyamide 66, and polyamide 666 being preferred, and polyamide 66 being more preferred. As described above, the polyamide resin used in this embodiment preferably includes a semi-aromatic polyamide resin. For example, it is more preferable that 90% by mass or more of the polyamide resin contained in the resin composition of this embodiment is a semi-aromatic polyamide resin. Here, a semi-aromatic polyamide resin is composed of diamine-derived structural units and dicarboxylic acid-derived structural units, wherein 20 to 80 mol% (preferably 30 to 80 mol%, more preferably 40 to 70 mol%) of the total structural units of the diamine-derived structural units and dicarboxylic acid-derived structural units contain aromatic rings.

[0015] Examples of semi-aromatic polyamide resins include terephthalic acid-based polyamide resins (polyamide 6T, polyamide 9T, polyamide 10T) and xylylenediamine-based polyamide resins, which will be discussed later.

[0016] The polyamide resin used in this embodiment may be recycled polyamide resin (including recovered products, material recycled products, chemical recycled products, etc.), rejected products, or scraps generated when molding molded products from resin compositions.

[0017] In this embodiment, a polyamide resin containing diamine-derived structural units and dicarboxylic acid-derived structural units, wherein 70 mol% or more of the diamine-derived structural units are derived from xylylenediamine (hereinafter sometimes referred to as "xylylenediamine-based polyamide resin") is preferred.

[0018] The diamine-derived structural units of the xylylenediamine-based polyamide resin are more preferably derived from xylylenediamine (preferably para-xylylenediamine and / or meta-xylylenediamine) in an amount of 75 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and particularly most preferably 99 mol% or more.

[0019] The xylylenediamine is preferably para-xylylenediamine and / or meta-xylylenediamine. The xylylenediamine preferably contains 0 to 100 mol% meta-xylylenediamine and 100 to 0 mol% para-xylylenediamine (provided that the sum of meta-xylylenediamine and para-xylylenediamine does not exceed 100 mol%), more preferably 10 to 100 mol% meta-xylylenediamine and 90 to 0 mol% para-xylylenediamine, even more preferably 20 to 100 mol% meta-xylylenediamine and 80 to 0 mol% para-xylylenediamine, even more preferably 40 to 100 mol% meta-xylylenediamine and 60 to 0 mol% para-xylylenediamine, and even more preferably 60 to 100 mol% meta-xylylenediamine and 40 to 0 mol% para-xylylenediamine. In xylylenediamine-based polyamide resins, it is preferable that the total of constituent units derived from para-xylylenediamine and meta-xylylenediamine constitutes preferably 80 mol% or more, more preferably 85 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, even more preferably 98 mol% or more, and even more preferably 99 mol% or more of the constituent units derived from diamine. The upper limit of the total of the constituent units derived from para-xylylenediamine and meta-xylylenediamine is 100 mol%.

[0020] Diamines other than meta-xylylenediamine and para-xylylenediamine that can be used as raw material diamine components for xylylenediamine-based polyamide resins include aliphatic diamines such as tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4-trimethyl-hexamethylenediamine, and 2,4,4-trimethylhexamethylenediamine, as well as 1,3-bis( Examples include alicyclic diamines such as aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, 1,3-diaminocyclohexane, 1,4-diaminocyclohexane, bis(4-aminocyclohexyl)methane, 2,2-bis(4-aminocyclohexyl)propane, bis(aminomethyl)decalin, and bis(aminomethyl)tricyclodecane, as well as aromatic ring-containing diamines such as bis(4-aminophenyl) ether, paraphenylenediamine, and bis(aminomethyl)naphthalene. One or more of these can be used in combination.

[0021] On the other hand, of the xylylenediamine-based polyamide resin, preferably 70 mol% or more, more preferably 75 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and especially most preferably 99 mol% or more, are derived from α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms (preferably adipic acid).

[0022] Preferred α,ω-linear aliphatic dicarboxylic acids having 4 to 20 carbon atoms for use as raw material dicarboxylic acid components in xylylenediamine-based polyamide resins include, for example, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, undecanediic acid, and 1,12-dodecanediic acid. One or more of these can be used in combination, but among these, at least one of adipic acid, sebacic acid, and 1,12-dodecanediic acid is preferred, with adipic acid and / or sebacic acid being more preferred, and adipic acid being even more preferred, since the melting point of the polyamide resin is within a range suitable for molding.

[0023] Examples of dicarboxylic acid components other than those mentioned above include phthalate compounds such as isophthalic acid, terephthalic acid, and orthophthalic acid, and isomers of naphthalenedicarboxylic acids such as 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid. One or more of these can be used in combination.

[0024] It should be noted that while xylylenediamine-based polyamide resins are mainly composed of diamine-derived and dicarboxylic acid-derived structural units, they do not completely exclude other structural units, and may also contain structural units derived from lactams such as ε-caprolactam and laurolactam, and aliphatic aminocarboxylic acids such as aminocaproic acid and aminoundecanoic acid. Here, "main component" refers to the structural unit in the xylylenediamine-based polyamide resin in which the total number of diamine-derived and dicarboxylic acid-derived structural units is the largest among all structural units. In this embodiment, it is preferable that the total of diamine-derived and dicarboxylic acid-derived structural units in the xylylenediamine-based polyamide resin accounts for 90% by mass or more of the total structural units, more preferably 95% by mass or more, even more preferably 97% by mass or more, and even more preferably 99% by mass or more.

[0025] It is also preferable to use polyamide resins manufactured using biomass raw materials (biomass polyamide resins) for xylylenediamine-based polyamide resins. By using biomass polyamide resins, it is possible to reduce the environmental impact. In xylylenediamine-based polyamide resins, bio-adipic acid can be used as a biomass raw material. Alternatively, adipic acid certified under Mass Balance Certification (ISCC PLUS) can be used. Mass Balance Certification quantifies the extent to which renewable and bio-based raw materials are used in each factory or production facility, and how much of that is used in the production and shipment of products, guaranteeing quality along with the certification itself.

[0026] In the resin composition of this embodiment, the content of xylylenediamine-based polyamide resin in 100 parts by mass of polyamide resin is preferably 70 parts by mass or more, more preferably 75 parts by mass or more, even more preferably 80 parts by mass or more, and may also be 100 parts by mass or less. Furthermore, the polyamide resin used in the resin composition of this embodiment is particularly preferably a blend of xylylenediamine-based polyamide resin and polyamide 66.

[0027] The melting point of the polyamide resin is preferably 150°C or higher, more preferably 180°C or higher, even more preferably 200°C or higher, preferably 350°C or lower, more preferably 330°C or lower, and even more preferably 300°C or lower.

[0028] The polyamide resin preferably has a lower limit of number-average molecular weight (Mn) of 6,000 or more, more preferably 8,000 or more, even more preferably 10,000 or more, and more preferably 100,000 or less, and more preferably 50,000 or less. Within this range, heat resistance, elastic modulus, dimensional stability, and moldability are improved.

[0029] The content of (A) polyamide resin in the resin composition of this embodiment is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, even more preferably 60% by mass or more, even more preferably 65% ​​by mass or more, and also preferably 80% by mass or less, and may be 75% by mass or less. Setting it above the lower limit allows the blending ratio of reinforcing fibers to be suppressed to some extent, and tends to make it easier to adjust the fluidity balance of the resin composition. Setting it below the upper limit allows the blending ratio of reinforcing fibers to be increased, and tends to make it easier to obtain high physical properties in terms of rigidity and strength. The resin composition of this embodiment may contain only one type of polyamide resin (A), or it may contain two or more types. When it contains two or more types, it is preferable that the total amount is within the above range.

[0030] <(B) Glass fiber> The resin composition of the present embodiment contains (B) glass fiber in a proportion of 15 parts by mass or more and less than 42 parts by mass with respect to 100 parts by mass of (A) polyamide resin. By blending (B) glass fiber, a molded product excellent in mechanical properties can be obtained. (B) Glass fiber refers to a fiber having a circular or polygonal cross-sectional shape cut at right angles to the length direction and presenting a fibrous appearance. (B) Glass fiber is composed of a glass composition such as A glass, C glass, E glass, S glass, R glass, M glass, D glass, etc. In particular, E glass (alkali-free glass) is preferable. (B) It is more preferable to use glass fiber that has been surface-treated with a surface treatment agent such as a coupling agent. Glass fiber with a surface treatment agent attached is preferable because it is excellent in durability, heat and humidity resistance, hydrolysis resistance, and heat shock resistance.

[0031] (B) The glass fiber used in the resin composition of the present embodiment may be single fiber or a plurality of single fibers twisted together. (B) The form of glass fiber may be any of "glass roving" obtained by continuously winding single fiber or a plurality of single fibers twisted together, "chopped strand" cut to a length of 1 to 10 mm, "milled fiber" ground to a length of 10 to 500 μm, etc. Such glass fiber is commercially available under the trade names of "Glassron Chopped Strand" and "Glassron Milled Fiber" from Asahi Fiber Glass Co., Ltd. and is easily available. (B) Glass fiber with different forms can also be used in combination. In the present embodiment, chopped strand with a cut length of 1 to 10 mm (preferably a cut length of 1 to 5 mm) is preferable.

[0032] (B) The glass fiber used in the present embodiment preferably has an average cross-sectional area of 15 μm 2 or more, more preferably 20 μm 2 or more, still more preferably 25 μm 2 or more, and preferably 100 μm 2 or less, more preferably 85 μm 2It is more preferable that the following conditions are met. Setting the value above the lower limit allows for a reduction in the number of glass fibers per unit of material, which tends to reduce the number of fracture initiation points. Setting the value below the upper limit allows for a reduction in the number of glass fibers per unit of material, which reduces the number of times the mating material in sliding parts is abraded, which tends to further improve sliding performance. If the resin composition of this embodiment contains two or more types of glass fibers with different cross-sectional areas, the average cross-sectional area of ​​the glass fibers shall be the sum (weighted average) of the values ​​obtained by multiplying the cross-sectional area of ​​each glass fiber by the mass fraction of each glass fiber. The average cross-sectional area of ​​glass fibers is calculated by selecting 100 fibers using a scanning electron microscope (SEM), measuring the diameter of each fiber, and then calculating the average fiber diameter. The cross-sectional area is then calculated from the average fiber diameter.

[0033] Furthermore, the (B) glass fiber used in this embodiment may have a circular or flattened cross-section, but a flattened cross-section is preferred.

[0034] The content of (B) glass fibers in the resin composition used in this embodiment is 15 parts by mass or more and less than 42 parts by mass per 100 parts by mass of (A) polyamide resin. Setting the content above the lower limit tends to further improve the mechanical strength of the resulting molded article. Setting the content below the upper limit tends to further improve the sliding properties of the resulting molded article. The content of (B) glass fibers is preferably 20 parts by mass or more, may be 25 parts by mass or more, more preferably 40 parts by mass or less, even more preferably 35 parts by mass or less, and most preferably 30 parts by mass or less, per 100 parts by mass of (A) polyamide resin. The content of (B) glass fibers in the resin composition of this embodiment is preferably 10% by mass or more, more preferably 15% by mass or more, preferably less than 30% by mass, and more preferably 25% by mass or less. The resin composition of this embodiment may contain only one type of (B) glass fiber, or it may contain two or more types. If it contains two or more types, the total amount will be within the above range. Note that the content of (B) glass fiber in this embodiment includes the amount of sizing agent and surface treatment agent.

[0035] In the resin composition of this embodiment, the content of inorganic fillers other than (B) glass fibers is preferably less than 2 parts by mass, more preferably less than 1 part by mass, and even more preferably less than 0.5 parts by mass, per 100 parts by mass of (A) polyamide resin. Furthermore, the lower limit of the content is preferably 0 parts by mass. In addition, (B) inorganic fillers other than glass fibers that also correspond to nucleating agents described later are treated as nucleating agents in this specification.

[0036] <(C)Polyolefins with an acid value of 2.0 mgKOH / g or less, measured according to JIS K0070, and a weight-average molecular weight of 1000 to 20000> The resin composition of this embodiment contains (C) a polyolefin having an acid value of 2.0 mgKOH / g or less as measured according to JIS K0070 and a weight-average molecular weight of 1000 to 20000, in an amount of 4.1 to 30.0 parts by mass per 100 parts by mass of (A) polyamide resin. The inclusion of (C) polyolefin improves the sliding properties of the resulting molded article. The (C) polyolefin mentioned above is exemplified by polyethylene, polypropylene, and polyethylene / polypropylene copolymer, with polyethylene being preferred. In this embodiment, the weight-average molecular weight of (C) polyolefin is 1000 or more, preferably 2000 or more, more preferably 3000 or more, even more preferably 3500 or more, and also 20000 or less, preferably 18000 or less, more preferably 15000 or less, even more preferably 10000 or less, even more preferably 8000 or less, and even more preferably 6000 or less. Setting it above the lower limit tends to further improve the effect of suppressing the deterioration of physical properties due to polyolefin. Also, setting it below the upper limit tends to further improve the effect of polyolefin easily precipitating on the surface of the molded product, thereby improving sliding properties. (C) If the mixture contains two or more types of polyolefins, the weight-average molecular weight of the polyolefins shall be the weight-average molecular weight of the mixture.

[0037] The aforementioned (C) polyolefin has an acid value of 2.0 mgKOH / g or less, as measured according to JIS K0070, but it is preferable that the acid value is less than 1.0 mgKOH / g. Furthermore, the lower limit of the acid value is 0 mgKOH / g. (C) If the mixture contains two or more types of polyolefins, the acid value of the polyolefins shall be the acid value of the mixture.

[0038] The resin composition of this embodiment may contain only one type of (C) polyolefin, or it may contain two or more types. When it contains two or more types, it is preferable that the weight-average molecular weight of the mixture is within the above range.

[0039] The content of (C) polyolefin in the resin composition of this embodiment is 4.1 parts by mass or more, preferably 4.5 parts by mass or more, more preferably 5.0 parts by mass or more, and also 30.0 parts by mass or less, preferably 25.0 parts by mass or less, more preferably 20.0 parts by mass or less, even more preferably 15.0 parts by mass or less, even more preferably 10.0 parts by mass or less, and even more preferably 7.0 parts by mass or less. Setting the content above the lower limit tends to lower the coefficient of friction of the resulting molded article. Setting the content below the upper limit tends to further improve the physical properties of the resulting molded article. The resin composition of this embodiment may contain only one type of (C) polyolefin, or it may contain two or more types. When it contains two or more types, it is preferable that the total amount is within the above range.

[0040] <(D) In ​​accordance with ISO1133, the melt volume rate (MVR) measured under conditions of 210°C and a load of 5 kgf was 0.5 to 20.5 cm³. 3 / 10 minutes, and a polyolefin having polar groups> The resin composition of this embodiment has a melt volume rate (MVR) of 0.5 to 20.5 cm³ measured under the conditions of (D)ISO1133, 210°C, and a load of 5 kgf. 3 The ratio is 10 min, and the mixture contains (D) polyolefin having polar groups in an amount of 0.1 to 5.1 parts by mass per 100 parts by mass of (A) polyamide resin. The inclusion of (D) polyolefin results in a molded product with superior mechanical strength. The (D) polyolefin is exemplified by polyethylene, polypropylene, and polyethylene / polypropylene copolymer, with polyethylene being preferred.

[0041] The polar group is preferably an acidic group, more preferably a carboxylic acid-containing group, and even more preferably a maleic anhydride group. In other words, the (D) polyolefin in this embodiment is preferably a maleic anhydride-modified polyolefin. Furthermore, when the polar group is an acidic group, the acid value of (D) polyolefin is preferably 1.0 mg KOH / g or more, more preferably 5 mg KOH / g or more, even more preferably 10 mg KOH / g or more, even more preferably 15 mg KOH / g or more, even more preferably 17 mg KOH / g or more, and also preferably 100 mg KOH / g or less. It is more preferable that the amount be 70 mg KOH / g or less, even more preferable that it be 50 mg KOH / g or less, even more preferable that it be 40 mg KOH / g or less, and even more preferable that it be 30 mg KOH / g or less. Setting it above the lower limit tends to further improve the effect of increasing mechanical strength due to the reaction between the amide group and the acid group. Also, setting it below the upper limit tends to further improve the effect of suppressing the decrease in sliding properties. When the resin material of this embodiment contains two or more types of (D) polyolefins, it is preferable that the acid value of the mixture falls within the above range.

[0042] (D) The MVR of polyolefins is 0.5 cm 3 / 10 minutes or more and 1.0 cm 3 Preferably 10 minutes or more, and 3.0 cm 3 More preferably 10 minutes or longer, and 5.0 cm 3 It is even more preferable that it be 10 minutes or longer, and 8.0 cm 3 It is even more preferable that it be 10 minutes or longer, and 10.0 cm 3 It is even more preferable that the duration be 10 minutes or longer, and also 20.5 cm. 3 Less than 10 minutes, 18.0cm 3 Preferably 10 minutes or less, and 16.0 cm 3 It is more preferable that the interval be 10 minutes or less. By setting it above the lower limit, (D) polyolefin functions effectively as a compatibilizer, and the mechanical properties of the resulting molded article tend to improve. Also, by setting it below the upper limit, the sliding properties of the resulting molded article tend to improve. When the resin composition of this embodiment contains two or more (D) polyolefins, it is preferable that the MVR of the mixture falls within the above range.

[0043] The content of (D) polyolefin in the resin composition of this embodiment is 0.1 parts by mass or more, preferably 0.1 parts by mass or more, more preferably 1.0 part by mass or more, and 5.1 parts by mass or less, preferably 4.0 parts by mass or less, more preferably 3.0 parts by mass or less, and even more preferably 2.0 parts by mass or less, with respect to 100 parts by mass of (A) polyamide resin. Setting the content above the lower limit allows (D) polyolefin to act as a compatibilizer, which tends to further improve the strength of the resulting molded article. Setting the content below the upper limit tends to further improve the sliding properties. The resin composition of this embodiment may contain only one type of (D) polyolefin, or it may contain two or more types. When it contains two or more types, it is preferable that the total amount is within the above range.

[0044] In the resin composition of this embodiment, the mass ratio of (C) to (D) ((C) / (D)) is preferably 2.0 or higher, more preferably 3.1 or higher, even more preferably 3.3 or higher, even more preferably 3.5 or higher, and also preferably 6.0 or lower, more preferably 5.0 or lower, and even more preferably 4.5 or lower. Setting the mass ratio of (C) to (D) ((C) / (D)) to be above the lower limit tends to further improve the sliding properties of the resulting molded article, and setting it to be below the upper limit tends to improve the sliding properties and mechanical strength of the resulting molded article in a well-balanced manner.

[0045] <Nuclear agent> The resin composition of this embodiment may contain a nucleating agent. Including a nucleating agent can improve the appearance of the resulting molded article. The nucleating agent may be an organic crystalline nucleating agent or an inorganic crystalline nucleating agent, but an amorphous nucleating agent is preferred, and talc is more preferred. The talc may be surface-treated with at least one compound selected from polyorganohydrogensiloxanes and organopolysiloxanes. In this case, the amount of siloxane compound attached to the talc is preferably 0.1 to 5% by mass of the talc. If the resin composition of this embodiment contains a nucleating agent, its content is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.3% by mass or more, and even more preferably 0.4% by mass or more, based on 100% by mass of the resin composition. Furthermore, the upper limit of the nucleating agent content is preferably 2% by mass or less, more preferably 1.5% by mass or less, even more preferably 1.2% by mass or less, and even more preferably 0.8% by mass or less, based on 100% by mass of the resin composition. The resin composition of this embodiment may contain only one nucleating agent or two or more. When two or more are included, it is preferable that the total amount is within the above range.

[0046] <Release agent> The resin composition of this embodiment preferably contains a mold release agent. Release agents are primarily used to improve the productivity of molding resin compositions. Examples of release agents include aliphatic carboxylic acid amides, aliphatic carboxylic acids, esters of aliphatic carboxylic acids and alcohols, aliphatic hydrocarbon compounds with a number average molecular weight of 200 to 15,000, polysiloxane-based silicone oils, and higher fatty acid metal salts, with higher fatty acid metal salts being preferred. In particular, in the resin composition of this embodiment, since the amount of glass fibers is 20 to 50% by mass of the resin composition, higher fatty acid metal salts, which are generally strongly alkaline release agents, can also be preferably used. The higher fatty acids constituting the higher fatty acid metal salt are preferably fatty acids having 8 or more carbon atoms, and more preferably fatty acids having 8 to 40 carbon atoms. The fatty acids are preferably monocarboxylic acids. Examples of higher fatty acids include saturated fatty acids such as octic acid, lauric acid, myristic acid, palmitic acid, stearic acid, 12-hydroxystearic acid, behenic acid, montanic acid, and sebacic acid, as well as unsaturated fatty acids such as erucic acid, oleic acid, and ricinoleic acid. Preferably, montanic acid, 12-hydroxystearic acid, and behenic acid are used, and more preferably montanic acid. The higher fatty acid metal salts that can be used in this embodiment are preferably 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. Preferably, the salts are calcium salts, magnesium salts, zinc salts, and aluminum salts, and more preferably calcium salts. Examples of higher fatty acid metal salts include calcium 12-hydroxystearate, zinc 12-hydroxystearate, magnesium 12-hydroxystearate, aluminum 12-hydroxystearate, calcium behenate, zinc behenate, magnesium behenate, calcium montana, zinc montana, magnesium montana, and aluminum montana, with calcium montana being preferred.

[0047] For further details regarding the release agent, please refer to paragraphs 0037-0042 of Japanese Patent Publication No. 2016-196563, paragraphs 0067-0070 of Japanese Patent Publication No. 2021-161125, and paragraphs 0048-0058 of Japanese Patent Publication No. 2016-078318, in addition to the above, and these contents are incorporated herein by reference.

[0048] The release agent content is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, based on 100% by mass of the resin composition. The upper limit is preferably 1% by mass or less, more preferably 0.8% by mass or less, and even more preferably 0.5% by mass or less. By setting the content within this range, good release properties can be achieved when performing mold molding such as injection molding, and mold contamination can be effectively suppressed. The release agent may be used alone or in combination of two or more types. When using two or more types, it is preferable that the total amount be within the above range.

[0049] <Coloring agent> The resin composition of this embodiment may contain a coloring agent, particularly a black coloring agent. While there are no specific requirements for the type of black colorant, examples include pigments such as carbon black and titanium black, as well as nigrosine and aniline black, with carbon black being preferred.

[0050] Any conventionally known carbon black can be used as the carbon black in this embodiment. Examples include furnace black, channel black, Ketjen black, and acetylene black. In particular, a carbon black with excellent opacity and a DBP absorption of 30-300 g / 100 cm² can be used. 3 Using carbon black, especially furnace black, is preferable because it allows for the development of a stable color tone.

[0051] Carbon black may be included as a masterbatch. When included as a masterbatch, it is preferable that the masterbatch be based on a polyamide resin.

[0052] The content of the coloring agent (preferably a black coloring agent) in the resin composition of this embodiment is preferably 0.1% by mass or more, preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, and most preferably 1% by mass or less, based on 100% by mass of the resin composition. By keeping it below the above upper limit, higher mechanical properties tend to be obtained. The resin composition of this embodiment may contain only one coloring agent or two or more. When two or more coloring agents are included, it is preferable that the total amount is within the above range.

[0053] <Alkali metal carbonates and / or alkaline earth metal carbonates> The resin composition of this embodiment contains less than 2 parts by mass of alkali metal carbonates and / or alkaline earth metal carbonates per 100 parts by mass of (A) polyamide resin. This configuration effectively suppresses the formation of fracture initiations in the molded product, resulting in a molded product with excellent mechanical properties. The content of alkali metal carbonates and / or alkaline earth metal carbonates is preferably less than 1.5 parts by mass, more preferably less than 1.0 part by mass, even more preferably less than 0.5 parts by mass, even more preferably less than 0.3 parts by mass, even more preferably less than 0.1 parts by mass, even more preferably less than 0.01 parts by mass, and especially most preferably less than 0.0001 parts by mass, per 100 parts by mass of (A) polyamide resin. The lower limit of the content is preferably 0 parts by mass.

[0054] <Other additives> The resin composition of this embodiment may also contain additives other than those mentioned above. Other additives include flame retardants, flame retardant enhancers, light stabilizers, heat stabilizers (antioxidants), ultraviolet absorbers, fluorescent whitening agents, anti-dripping agents, antistatic agents, anti-fogging agents, anti-blocking agents, flow improvers, plasticizers, dispersants, antimicrobial agents, alkalis, hydrolysis resistance improvers, matting agents, plasticizers, dispersants, antistatic agents, color inhibitors, and gelling inhibitors. Details of these can be found in paragraphs 0130-0155 of Japanese Patent No. 4894982, which are incorporated herein by reference. Furthermore, the resin composition of this embodiment may contain additives described in paragraphs 0047 to 0103 of International Publication No. 2021 / 241471, without departing from the spirit of the present invention, and this is incorporated herein. The other additives, in total, are preferably 20.0% by mass or less of the resin composition, more preferably less than 10.0% by mass, even more preferably less than 5.0% by mass, and even more preferably less than 1.0% by mass. Only one type of other additive may be used, or two or more types may be used in combination. In this embodiment, the resin composition is prepared such that the total amount of each component is 100% by mass, with the contents of (A) polyamide resin, (B) glass fiber, (C) polyolefin, (D) polyolefin, and other components added as needed being adjusted accordingly. In this embodiment, an example is given in which the total amount of (A) polyamide resin, (B) glass fiber, (C) polyolefin, (D) polyolefin, and release agents, nucleating agents, and colorants added as needed constitutes 99% by mass or more of the resin composition.

[0055] <Method for producing resin compositions> In this embodiment, the method for producing the resin composition is not particularly specified, and a wide range of known methods for producing thermoplastic resin compositions can be used. Specifically, the resin composition can be produced by pre-mixing each component using various mixers such as a tumbler or a Henschel mixer, and then melt-kneading them using a Banbury mixer, rolls, brabender, single-screw extruder, twin-screw extruder, kneader, etc. In this embodiment, melt-kneading using a twin-screw extruder is preferred.

[0056] Furthermore, for example, a resin composition can be manufactured by supplying the components to an extruder using a feeder, either without pre-mixing them or by pre-mixing only some of the components, and then melt-kneading them together. Furthermore, for example, a composition obtained by pre-mixing some of the components and supplying it to an extruder for melt-kneading can be used as a masterbatch, and pellets can be produced by mixing this masterbatch with the remaining components again and melt-kneading it.

[0057] The cylinder temperature is preferably 20°C or higher than the melting point of the polyamide resin, more preferably 30°C or higher than the melting point of the polyamide resin, even more preferably 40°C or higher than the melting point of the polyamide resin, and preferably 100°C or lower than the melting point of the polyamide resin, more preferably 80°C or lower than the melting point of the polyamide resin, and even more preferably 70°C or lower than the melting point of the polyamide resin. Setting the temperature above the lower limit tends to improve the fluidity of (A) polyamide resin and (C) olefin, and further improve their compatibility. Setting the temperature below the upper limit tends to effectively suppress vent-up during manufacturing.

[0058] <Physical properties of resin compositions> The resin composition of this embodiment has an abrasion amount of 30 x 10, measured according to the JIS K7218 (A) method. -2 mm 3 Preferably, it is less than or equal to / kgf·km, and 2.0x10 -2 mm 3 It is more preferable that it be less than or equal to / kgf·km, and also 0.1x10 -2 mm 3 A value of / kgf·km or higher is practical.

[0059] In this embodiment, the resin composition is measured under conditions of a linear velocity of 100 mm / second, with an initial pressurizing load of 5 kgf, and the pressurizing load is increased by 5 kgf every minute. The measured coefficient of dynamic friction is preferably less than 0.09, more preferably 0.08 or less, and practically 0.0001 or more. The Charpy impact strength, wear amount, and coefficient of dynamic friction described above are measured according to the examples described later.

[0060] <Molded products> The molded article of this embodiment is formed from the resin composition or pellets of this embodiment. In this embodiment, molded articles may be manufactured by molding pellets obtained by pelletizing a resin composition using various molding methods. Alternatively, molded articles may be manufactured by directly molding a resin composition that has been melt-kneaded in a kneader without going through pellets. The above resin composition (e.g., pellets) is molded into a molded product using various molding methods. There are no particular restrictions on the shape of the molded product, and it can be appropriately selected according to the application and purpose of the molded product. Examples include flat plates, rods, cylindrical shapes, annular shapes, circular shapes, elliptical shapes, polygonal shapes, irregular shapes, hollow shapes, frame shapes, box shapes, panel shapes, button shapes, etc.

[0061] The method for molding the molded product is not particularly limited, and conventionally known molding methods can be used. Examples include injection molding, injection compression molding, extrusion molding, shape extrusion, transfer molding, hollow molding, gas-assisted hollow molding, blow molding, extrusion blow molding, IMC (in-mold coating) molding, rotational molding, multilayer molding, two-color molding, insert molding, sandwich molding, foam molding, and pressure molding. In particular, the resin composition of this embodiment is suitable for molded products obtained by injection molding, injection compression molding, and extrusion molding, and is especially suitable for molded products obtained by injection molding (injection molded products). However, it goes without saying that the resin composition of this embodiment is not limited to molded products obtained by these methods.

[0062] <Application> The application fields of the molded products of this embodiment are not specifically defined, but they can be widely used in automobile and other transport equipment parts, general machinery parts, precision machinery parts, electronic and electrical equipment parts, office automation equipment parts, building materials and housing equipment related parts, medical devices, leisure and sports goods, amusement equipment, medical supplies, daily necessities such as food packaging films, defense and aerospace products, etc. In particular, the molded product of this embodiment is suitably used as a sliding part. More specifically, it is suitable for bearing components that combine static elimination and electrical contact functions in the bearings of various rollers in copiers and printers, switching components, cassettes and trays used in semiconductor device manufacturing processes, lamps in hard disk drives, gears, rotating shafts, bearings, various gears, cams, end face materials for mechanical seals in power equipment, valve seats for valves, sealing members such as V-rings, rod packings, piston rings, and rider rings, and rotating shafts, rotating sleeves, pistons, and impellers of compressors. [Examples]

[0063] The present invention will be described in more detail below with reference to examples. The materials, amounts used, proportions, processing content, and processing procedures shown in the following examples can be modified as appropriate, as long as they do not depart from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below. If the measuring instruments used in the examples are difficult to obtain due to discontinuation or other reasons, measurements can be taken using other instruments with equivalent performance.

[0064] 1.Raw materials The following raw materials, as shown in Table 1, were used. [Table 1]

[0065] <Synthesis Example 1: Synthesis of PAMP6 (M / P molar ratio = 7:3)> In a reaction vessel equipped with a stirrer, condenser, condenser, thermometer, dropping device, nitrogen inlet tube, and strand die, 7220 g (49.4 mol) of adipic acid and 11.66 g of sodium acetate / sodium hypophosphite monohydrate (molar ratio = 1 / 1.5) were charged. After thorough nitrogen purging, the mixture was heated and melted to 170°C while stirring the system under a small stream of nitrogen. 6647 g (48.8 mol%, manufactured by Mitsubishi Gas Chemical Co., Ltd.) of mixed xylylenediamine with a molar ratio of metaxylylenediamine to paraxylylenediamine of 7 / 3 was added dropwise while stirring, and the internal temperature was continuously raised to 260°C over 2.5 hours while removing the condensation water produced from the system. After the dropwise addition was complete, the internal temperature was increased further, and when it reached 270°C, the pressure inside the reaction vessel was reduced, and the internal temperature was further increased to 280°C to continue the melt polycondensation reaction for 20 minutes. After that, the system was pressurized with nitrogen, and the obtained polymer was removed from the strand die and pelletized to obtain polyamide resin (PAMP6). The melting point was measured to be 256°C.

[0066] <Manufacturing of carbon black masterbatch> PAMP6 and carbon black components were blended in a tumbler, fed into a twin-screw extruder (Shibaura Machinery Co., Ltd., TEM26SS) from the base, and melt-kneaded to produce carbon black masterbatch pellets (CB concentration 30% by mass).

[0067] 3. Examples 1-3, Comparative Examples 1-8 <Compound> Each component was weighed to achieve the composition shown in Tables 2 and 3 below. The components, excluding the glass fibers, were blended in a tumbler. The mixture was then fed into a twin-screw extruder (Shibaura Machine Co., Ltd., TEM26SS) from the base, melted, and then the glass fibers were side-fed from one location to produce pellets. The temperature settings (cylinder temperature) of the twin-screw extruder are shown in Table 2 or Table 3. The values ​​of each component in Tables 2 and 3 are shown in mass percent.

[0068] <Bending properties> The pellets obtained by the above manufacturing method were dried at 120°C for 4 hours, and then ISO tensile test specimens (4 mm thick) were injection molded using an injection molding machine (NEX-140III, manufactured by Nissei Plastic Industrial Co., Ltd.) under the conditions of cylinder temperature 280°C, mold temperature 130°C, and molding cycle of 50 seconds. In accordance with ISO 178, the bending strength (in MPa) and bending modulus (in GPa) were measured at a temperature of 23°C.

[0069] <Charpy impact strength> The pellets obtained by the above manufacturing method were dried at 120°C for 4 hours, and then ISO tensile test specimens (4 mm thick) were injection molded using an injection molding machine (NEX-140III, manufactured by Nissei Plastic Industrial Co., Ltd.) under the conditions of cylinder temperature 280°C, mold temperature 130°C, and molding cycle of 50 seconds. In accordance with the ISO 179 standard, Charpy impact strength (notched Charpy and unnotched Charpy) was measured at a temperature of 23°C. The unit is kJ / m 2 As shown.

[0070] <Abrasion and friction test (coefficient of kinetic friction)> After drying the resin pellets obtained by the above manufacturing method at 120°C for 4 hours, a contact area of ​​2 cm² was used with NS-40 manufactured by Nissei Plastic Industrial Co., Ltd. 2 A hollow cylindrical test specimen (molded body) was injection molded. The cylinder temperature was 280°C and the mold temperature was 130°C. To prevent excessive fracture of the glass fibers due to high shear, the maximum injection pressure during injection molding was limited to 80% of the injection equipment capacity. Friction and wear tests were conducted between hollow cylindrical test specimens under a linear velocity of 100 mm / second, with an initial pressure of 5 kgf, and the pressure was increased by 5 kgf every minute.

[0071] <Sliding properties (specific friction)> After drying the resin pellets obtained by the above manufacturing method at 120°C for 4 hours, a contact area of ​​2 cm² was used with NS-40 manufactured by Nissei Plastic Industrial Co., Ltd. 2 A hollow cylindrical test specimen (molded body) was injection molded. The cylinder temperature was 280°C and the mold temperature was 130°C. To prevent excessive fracture of the glass fibers due to high shear, the maximum injection pressure during injection molding was limited to 80% of the injection equipment capacity. In accordance with JIS K7218(A) method, friction and wear tests were conducted on hollow cylindrical test specimens at a temperature of 23°C and 50% humidity for 20 hours under a linear speed of 100 mm / sec and a pressurized load of 10 kgf. The specific wear amount for the same material was measured for both the fixed and movable test specimens. The specific wear amount was calculated by dividing the volume of the worn-down specimen by the total distance traveled and the pressurized load. The unit of specific wear amount is ×10⁻⁶. -2 mm 3 This is shown as / (kgf·km).

[0072] [Table 2]

[0073] [Table 3]

[0074] The unit of specific friction in Tables 2 and 3 above is x10 -2 mm 3 It is / kgf·km.

[0075] Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications are possible without departing from the intent and scope of the invention.

Claims

1. (A) Per 100 parts by mass of polyamide resin, (B) Glass fiber 15 parts by mass or more and less than 42 parts by mass, (C) 4.1 to 30.0 parts by mass of polyolefin having an acid value of 2.0 mgKOH / g or less measured according to JIS K0070 and a weight-average molecular weight of 1000 to 20000, (D) In ​​accordance with ISO 1133, the melt volume rate (MVR) measured at 210°C and a load of 5 kgf was 0.5 to 20.5 cm³. ３ / 10 minutes, and comprising 0.1 to 5.1 parts by mass of a polyolefin having a polar group (excluding those corresponding to (C) polyolefin), A resin composition in which the content of alkali metal carbonates and / or alkaline earth metal carbonates is less than 2 parts by mass per 100 parts by mass of (A) polyamide resin.

2. The resin composition according to claim 1, wherein the content of the inorganic filler other than the glass fibers (B) is less than 2 parts by mass per 100 parts by mass of the polyamide resin (A).

3. The resin composition according to claim 1 or 2, wherein the (A) polyamide resin comprises a semi-aromatic polyamide resin.

4. The average cross-sectional area of ​​the glass fibers (B) is 15 to 100 μm². ２ The resin composition according to claim 1 or 2.

5. The resin composition according to claim 1 or 2, wherein the (D) polyolefin comprises a maleic anhydride-modified polyolefin.

6. The content of the inorganic filler excluding the glass fibers (B) is less than 2 parts by mass per 100 parts by mass of the polyamide resin (A). The (A) polyamide resin includes a semi-aromatic polyamide resin, The average cross-sectional area of ​​the glass fibers (B) is 40 to 100 μm². ２ And, The resin composition according to claim 1, wherein the (D) polyolefin comprises a maleic anhydride-modified polyolefin.

7. Pellets of the resin composition according to claim 1, 2, or 6.

8. A molded article formed from the resin composition according to claim 1, 2, or 6.

Images